fix: vendor deps and fix CI go-version, timeout, GOTOOLCHAIN (HAN-414)

- Run go mod vendor to eliminate proxy.golang.org network dependency - Set GOFLAGS=-mod=vendor at job env level so all go commands use vendor/ - Fix go-version from 1.23 to 1.24.0 to match go.mod - Move GOTOOLCHAIN=local to job-level env (not per-step inline) - Set cache: false on setup-go (cache is irrelevant with vendoring) - Add timeout-minutes: 15 so failures are caught quickly instead of 3h Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Co-authored-by: multica-agent <github@multica.ai>
2026-06-11 09:08:51 +10:00
parent 1f23f482c1
commit db806835aa
787 changed files with 390251 additions and 7 deletions
@@ -0,0 +1,27 @@
+Copyright 2009 The Go Authors.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google LLC nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.
@@ -0,0 +1,41 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+import "fmt"
+
+// Assemble converts insts into raw instructions suitable for loading
+// into a BPF virtual machine.
+//
+// Currently, no optimization is attempted, the assembled program flow
+// is exactly as provided.
+func Assemble(insts []Instruction) ([]RawInstruction, error) {
+	ret := make([]RawInstruction, len(insts))
+	var err error
+	for i, inst := range insts {
+		ret[i], err = inst.Assemble()
+		if err != nil {
+			return nil, fmt.Errorf("assembling instruction %d: %s", i+1, err)
+		}
+	}
+	return ret, nil
+}
+
+// Disassemble attempts to parse raw back into
+// Instructions. Unrecognized RawInstructions are assumed to be an
+// extension not implemented by this package, and are passed through
+// unchanged to the output. The allDecoded value reports whether insts
+// contains no RawInstructions.
+func Disassemble(raw []RawInstruction) (insts []Instruction, allDecoded bool) {
+	insts = make([]Instruction, len(raw))
+	allDecoded = true
+	for i, r := range raw {
+		insts[i] = r.Disassemble()
+		if _, ok := insts[i].(RawInstruction); ok {
+			allDecoded = false
+		}
+	}
+	return insts, allDecoded
+}
@@ -0,0 +1,222 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+// A Register is a register of the BPF virtual machine.
+type Register uint16
+
+const (
+	// RegA is the accumulator register. RegA is always the
+	// destination register of ALU operations.
+	RegA Register = iota
+	// RegX is the indirection register, used by LoadIndirect
+	// operations.
+	RegX
+)
+
+// An ALUOp is an arithmetic or logic operation.
+type ALUOp uint16
+
+// ALU binary operation types.
+const (
+	ALUOpAdd ALUOp = iota << 4
+	ALUOpSub
+	ALUOpMul
+	ALUOpDiv
+	ALUOpOr
+	ALUOpAnd
+	ALUOpShiftLeft
+	ALUOpShiftRight
+	aluOpNeg // Not exported because it's the only unary ALU operation, and gets its own instruction type.
+	ALUOpMod
+	ALUOpXor
+)
+
+// A JumpTest is a comparison operator used in conditional jumps.
+type JumpTest uint16
+
+// Supported operators for conditional jumps.
+// K can be RegX for JumpIfX
+const (
+	// K == A
+	JumpEqual JumpTest = iota
+	// K != A
+	JumpNotEqual
+	// K > A
+	JumpGreaterThan
+	// K < A
+	JumpLessThan
+	// K >= A
+	JumpGreaterOrEqual
+	// K <= A
+	JumpLessOrEqual
+	// K & A != 0
+	JumpBitsSet
+	// K & A == 0
+	JumpBitsNotSet
+)
+
+// An Extension is a function call provided by the kernel that
+// performs advanced operations that are expensive or impossible
+// within the BPF virtual machine.
+//
+// Extensions are only implemented by the Linux kernel.
+//
+// TODO: should we prune this list? Some of these extensions seem
+// either broken or near-impossible to use correctly, whereas other
+// (len, random, ifindex) are quite useful.
+type Extension int
+
+// Extension functions available in the Linux kernel.
+const (
+	// extOffset is the negative maximum number of instructions used
+	// to load instructions by overloading the K argument.
+	extOffset = -0x1000
+	// ExtLen returns the length of the packet.
+	ExtLen Extension = 1
+	// ExtProto returns the packet's L3 protocol type.
+	ExtProto Extension = 0
+	// ExtType returns the packet's type (skb->pkt_type in the kernel)
+	//
+	// TODO: better documentation. How nice an API do we want to
+	// provide for these esoteric extensions?
+	ExtType Extension = 4
+	// ExtPayloadOffset returns the offset of the packet payload, or
+	// the first protocol header that the kernel does not know how to
+	// parse.
+	ExtPayloadOffset Extension = 52
+	// ExtInterfaceIndex returns the index of the interface on which
+	// the packet was received.
+	ExtInterfaceIndex Extension = 8
+	// ExtNetlinkAttr returns the netlink attribute of type X at
+	// offset A.
+	ExtNetlinkAttr Extension = 12
+	// ExtNetlinkAttrNested returns the nested netlink attribute of
+	// type X at offset A.
+	ExtNetlinkAttrNested Extension = 16
+	// ExtMark returns the packet's mark value.
+	ExtMark Extension = 20
+	// ExtQueue returns the packet's assigned hardware queue.
+	ExtQueue Extension = 24
+	// ExtLinkLayerType returns the packet's hardware address type
+	// (e.g. Ethernet, Infiniband).
+	ExtLinkLayerType Extension = 28
+	// ExtRXHash returns the packets receive hash.
+	//
+	// TODO: figure out what this rxhash actually is.
+	ExtRXHash Extension = 32
+	// ExtCPUID returns the ID of the CPU processing the current
+	// packet.
+	ExtCPUID Extension = 36
+	// ExtVLANTag returns the packet's VLAN tag.
+	ExtVLANTag Extension = 44
+	// ExtVLANTagPresent returns non-zero if the packet has a VLAN
+	// tag.
+	//
+	// TODO: I think this might be a lie: it reads bit 0x1000 of the
+	// VLAN header, which changed meaning in recent revisions of the
+	// spec - this extension may now return meaningless information.
+	ExtVLANTagPresent Extension = 48
+	// ExtVLANProto returns 0x8100 if the frame has a VLAN header,
+	// 0x88a8 if the frame has a "Q-in-Q" double VLAN header, or some
+	// other value if no VLAN information is present.
+	ExtVLANProto Extension = 60
+	// ExtRand returns a uniformly random uint32.
+	ExtRand Extension = 56
+)
+
+// The following gives names to various bit patterns used in opcode construction.
+
+const (
+	opMaskCls uint16 = 0x7
+	// opClsLoad masks
+	opMaskLoadDest  = 0x01
+	opMaskLoadWidth = 0x18
+	opMaskLoadMode  = 0xe0
+	// opClsALU & opClsJump
+	opMaskOperand  = 0x08
+	opMaskOperator = 0xf0
+)
+
+const (
+	// +---------------+-----------------+---+---+---+
+	// | AddrMode (3b) | LoadWidth (2b)  | 0 | 0 | 0 |
+	// +---------------+-----------------+---+---+---+
+	opClsLoadA uint16 = iota
+	// +---------------+-----------------+---+---+---+
+	// | AddrMode (3b) | LoadWidth (2b)  | 0 | 0 | 1 |
+	// +---------------+-----------------+---+---+---+
+	opClsLoadX
+	// +---+---+---+---+---+---+---+---+
+	// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 |
+	// +---+---+---+---+---+---+---+---+
+	opClsStoreA
+	// +---+---+---+---+---+---+---+---+
+	// | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
+	// +---+---+---+---+---+---+---+---+
+	opClsStoreX
+	// +---------------+-----------------+---+---+---+
+	// | Operator (4b) | OperandSrc (1b) | 1 | 0 | 0 |
+	// +---------------+-----------------+---+---+---+
+	opClsALU
+	// +-----------------------------+---+---+---+---+
+	// |      TestOperator (4b)      | 0 | 1 | 0 | 1 |
+	// +-----------------------------+---+---+---+---+
+	opClsJump
+	// +---+-------------------------+---+---+---+---+
+	// | 0 | 0 | 0 |   RetSrc (1b)   | 0 | 1 | 1 | 0 |
+	// +---+-------------------------+---+---+---+---+
+	opClsReturn
+	// +---+-------------------------+---+---+---+---+
+	// | 0 | 0 | 0 |  TXAorTAX (1b)  | 0 | 1 | 1 | 1 |
+	// +---+-------------------------+---+---+---+---+
+	opClsMisc
+)
+
+const (
+	opAddrModeImmediate uint16 = iota << 5
+	opAddrModeAbsolute
+	opAddrModeIndirect
+	opAddrModeScratch
+	opAddrModePacketLen // actually an extension, not an addressing mode.
+	opAddrModeMemShift
+)
+
+const (
+	opLoadWidth4 uint16 = iota << 3
+	opLoadWidth2
+	opLoadWidth1
+)
+
+// Operand for ALU and Jump instructions
+type opOperand uint16
+
+// Supported operand sources.
+const (
+	opOperandConstant opOperand = iota << 3
+	opOperandX
+)
+
+// An jumpOp is a conditional jump condition.
+type jumpOp uint16
+
+// Supported jump conditions.
+const (
+	opJumpAlways jumpOp = iota << 4
+	opJumpEqual
+	opJumpGT
+	opJumpGE
+	opJumpSet
+)
+
+const (
+	opRetSrcConstant uint16 = iota << 4
+	opRetSrcA
+)
+
+const (
+	opMiscTAX = 0x00
+	opMiscTXA = 0x80
+)
@@ -0,0 +1,80 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package bpf implements marshaling and unmarshaling of programs for the
+Berkeley Packet Filter virtual machine, and provides a Go implementation
+of the virtual machine.
+
+BPF's main use is to specify a packet filter for network taps, so that
+the kernel doesn't have to expensively copy every packet it sees to
+userspace. However, it's been repurposed to other areas where running
+user code in-kernel is needed. For example, Linux's seccomp uses BPF
+to apply security policies to system calls. For simplicity, this
+documentation refers only to packets, but other uses of BPF have their
+own data payloads.
+
+BPF programs run in a restricted virtual machine. It has almost no
+access to kernel functions, and while conditional branches are
+allowed, they can only jump forwards, to guarantee that there are no
+infinite loops.
+
+# The virtual machine
+
+The BPF VM is an accumulator machine. Its main register, called
+register A, is an implicit source and destination in all arithmetic
+and logic operations. The machine also has 16 scratch registers for
+temporary storage, and an indirection register (register X) for
+indirect memory access. All registers are 32 bits wide.
+
+Each run of a BPF program is given one packet, which is placed in the
+VM's read-only "main memory". LoadAbsolute and LoadIndirect
+instructions can fetch up to 32 bits at a time into register A for
+examination.
+
+The goal of a BPF program is to produce and return a verdict (uint32),
+which tells the kernel what to do with the packet. In the context of
+packet filtering, the returned value is the number of bytes of the
+packet to forward to userspace, or 0 to ignore the packet. Other
+contexts like seccomp define their own return values.
+
+In order to simplify programs, attempts to read past the end of the
+packet terminate the program execution with a verdict of 0 (ignore
+packet). This means that the vast majority of BPF programs don't need
+to do any explicit bounds checking.
+
+In addition to the bytes of the packet, some BPF programs have access
+to extensions, which are essentially calls to kernel utility
+functions. Currently, the only extensions supported by this package
+are the Linux packet filter extensions.
+
+# Examples
+
+This packet filter selects all ARP packets.
+
+	bpf.Assemble([]bpf.Instruction{
+		// Load "EtherType" field from the ethernet header.
+		bpf.LoadAbsolute{Off: 12, Size: 2},
+		// Skip over the next instruction if EtherType is not ARP.
+		bpf.JumpIf{Cond: bpf.JumpNotEqual, Val: 0x0806, SkipTrue: 1},
+		// Verdict is "send up to 4k of the packet to userspace."
+		bpf.RetConstant{Val: 4096},
+		// Verdict is "ignore packet."
+		bpf.RetConstant{Val: 0},
+	})
+
+This packet filter captures a random 1% sample of traffic.
+
+	bpf.Assemble([]bpf.Instruction{
+		// Get a 32-bit random number from the Linux kernel.
+		bpf.LoadExtension{Num: bpf.ExtRand},
+		// 1% dice roll?
+		bpf.JumpIf{Cond: bpf.JumpLessThan, Val: 2^32/100, SkipFalse: 1},
+		// Capture.
+		bpf.RetConstant{Val: 4096},
+		// Ignore.
+		bpf.RetConstant{Val: 0},
+	})
+*/
+package bpf // import "golang.org/x/net/bpf"
@@ -0,0 +1,726 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+import "fmt"
+
+// An Instruction is one instruction executed by the BPF virtual
+// machine.
+type Instruction interface {
+	// Assemble assembles the Instruction into a RawInstruction.
+	Assemble() (RawInstruction, error)
+}
+
+// A RawInstruction is a raw BPF virtual machine instruction.
+type RawInstruction struct {
+	// Operation to execute.
+	Op uint16
+	// For conditional jump instructions, the number of instructions
+	// to skip if the condition is true/false.
+	Jt uint8
+	Jf uint8
+	// Constant parameter. The meaning depends on the Op.
+	K uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (ri RawInstruction) Assemble() (RawInstruction, error) { return ri, nil }
+
+// Disassemble parses ri into an Instruction and returns it. If ri is
+// not recognized by this package, ri itself is returned.
+func (ri RawInstruction) Disassemble() Instruction {
+	switch ri.Op & opMaskCls {
+	case opClsLoadA, opClsLoadX:
+		reg := Register(ri.Op & opMaskLoadDest)
+		sz := 0
+		switch ri.Op & opMaskLoadWidth {
+		case opLoadWidth4:
+			sz = 4
+		case opLoadWidth2:
+			sz = 2
+		case opLoadWidth1:
+			sz = 1
+		default:
+			return ri
+		}
+		switch ri.Op & opMaskLoadMode {
+		case opAddrModeImmediate:
+			if sz != 4 {
+				return ri
+			}
+			return LoadConstant{Dst: reg, Val: ri.K}
+		case opAddrModeScratch:
+			if sz != 4 || ri.K > 15 {
+				return ri
+			}
+			return LoadScratch{Dst: reg, N: int(ri.K)}
+		case opAddrModeAbsolute:
+			if ri.K > extOffset+0xffffffff {
+				return LoadExtension{Num: Extension(-extOffset + ri.K)}
+			}
+			return LoadAbsolute{Size: sz, Off: ri.K}
+		case opAddrModeIndirect:
+			return LoadIndirect{Size: sz, Off: ri.K}
+		case opAddrModePacketLen:
+			if sz != 4 {
+				return ri
+			}
+			return LoadExtension{Num: ExtLen}
+		case opAddrModeMemShift:
+			return LoadMemShift{Off: ri.K}
+		default:
+			return ri
+		}
+
+	case opClsStoreA:
+		if ri.Op != opClsStoreA || ri.K > 15 {
+			return ri
+		}
+		return StoreScratch{Src: RegA, N: int(ri.K)}
+
+	case opClsStoreX:
+		if ri.Op != opClsStoreX || ri.K > 15 {
+			return ri
+		}
+		return StoreScratch{Src: RegX, N: int(ri.K)}
+
+	case opClsALU:
+		switch op := ALUOp(ri.Op & opMaskOperator); op {
+		case ALUOpAdd, ALUOpSub, ALUOpMul, ALUOpDiv, ALUOpOr, ALUOpAnd, ALUOpShiftLeft, ALUOpShiftRight, ALUOpMod, ALUOpXor:
+			switch operand := opOperand(ri.Op & opMaskOperand); operand {
+			case opOperandX:
+				return ALUOpX{Op: op}
+			case opOperandConstant:
+				return ALUOpConstant{Op: op, Val: ri.K}
+			default:
+				return ri
+			}
+		case aluOpNeg:
+			return NegateA{}
+		default:
+			return ri
+		}
+
+	case opClsJump:
+		switch op := jumpOp(ri.Op & opMaskOperator); op {
+		case opJumpAlways:
+			return Jump{Skip: ri.K}
+		case opJumpEqual, opJumpGT, opJumpGE, opJumpSet:
+			cond, skipTrue, skipFalse := jumpOpToTest(op, ri.Jt, ri.Jf)
+			switch operand := opOperand(ri.Op & opMaskOperand); operand {
+			case opOperandX:
+				return JumpIfX{Cond: cond, SkipTrue: skipTrue, SkipFalse: skipFalse}
+			case opOperandConstant:
+				return JumpIf{Cond: cond, Val: ri.K, SkipTrue: skipTrue, SkipFalse: skipFalse}
+			default:
+				return ri
+			}
+		default:
+			return ri
+		}
+
+	case opClsReturn:
+		switch ri.Op {
+		case opClsReturn | opRetSrcA:
+			return RetA{}
+		case opClsReturn | opRetSrcConstant:
+			return RetConstant{Val: ri.K}
+		default:
+			return ri
+		}
+
+	case opClsMisc:
+		switch ri.Op {
+		case opClsMisc | opMiscTAX:
+			return TAX{}
+		case opClsMisc | opMiscTXA:
+			return TXA{}
+		default:
+			return ri
+		}
+
+	default:
+		panic("unreachable") // switch is exhaustive on the bit pattern
+	}
+}
+
+func jumpOpToTest(op jumpOp, skipTrue uint8, skipFalse uint8) (JumpTest, uint8, uint8) {
+	var test JumpTest
+
+	// Decode "fake" jump conditions that don't appear in machine code
+	// Ensures the Assemble -> Disassemble stage recreates the same instructions
+	// See https://github.com/golang/go/issues/18470
+	if skipTrue == 0 {
+		switch op {
+		case opJumpEqual:
+			test = JumpNotEqual
+		case opJumpGT:
+			test = JumpLessOrEqual
+		case opJumpGE:
+			test = JumpLessThan
+		case opJumpSet:
+			test = JumpBitsNotSet
+		}
+
+		return test, skipFalse, 0
+	}
+
+	switch op {
+	case opJumpEqual:
+		test = JumpEqual
+	case opJumpGT:
+		test = JumpGreaterThan
+	case opJumpGE:
+		test = JumpGreaterOrEqual
+	case opJumpSet:
+		test = JumpBitsSet
+	}
+
+	return test, skipTrue, skipFalse
+}
+
+// LoadConstant loads Val into register Dst.
+type LoadConstant struct {
+	Dst Register
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadConstant) Assemble() (RawInstruction, error) {
+	return assembleLoad(a.Dst, 4, opAddrModeImmediate, a.Val)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadConstant) String() string {
+	switch a.Dst {
+	case RegA:
+		return fmt.Sprintf("ld #%d", a.Val)
+	case RegX:
+		return fmt.Sprintf("ldx #%d", a.Val)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadScratch loads scratch[N] into register Dst.
+type LoadScratch struct {
+	Dst Register
+	N   int // 0-15
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadScratch) Assemble() (RawInstruction, error) {
+	if a.N < 0 || a.N > 15 {
+		return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
+	}
+	return assembleLoad(a.Dst, 4, opAddrModeScratch, uint32(a.N))
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadScratch) String() string {
+	switch a.Dst {
+	case RegA:
+		return fmt.Sprintf("ld M[%d]", a.N)
+	case RegX:
+		return fmt.Sprintf("ldx M[%d]", a.N)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadAbsolute loads packet[Off:Off+Size] as an integer value into
+// register A.
+type LoadAbsolute struct {
+	Off  uint32
+	Size int // 1, 2 or 4
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadAbsolute) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegA, a.Size, opAddrModeAbsolute, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadAbsolute) String() string {
+	switch a.Size {
+	case 1: // byte
+		return fmt.Sprintf("ldb [%d]", a.Off)
+	case 2: // half word
+		return fmt.Sprintf("ldh [%d]", a.Off)
+	case 4: // word
+		if a.Off > extOffset+0xffffffff {
+			return LoadExtension{Num: Extension(a.Off + 0x1000)}.String()
+		}
+		return fmt.Sprintf("ld [%d]", a.Off)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadIndirect loads packet[X+Off:X+Off+Size] as an integer value
+// into register A.
+type LoadIndirect struct {
+	Off  uint32
+	Size int // 1, 2 or 4
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadIndirect) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegA, a.Size, opAddrModeIndirect, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadIndirect) String() string {
+	switch a.Size {
+	case 1: // byte
+		return fmt.Sprintf("ldb [x + %d]", a.Off)
+	case 2: // half word
+		return fmt.Sprintf("ldh [x + %d]", a.Off)
+	case 4: // word
+		return fmt.Sprintf("ld [x + %d]", a.Off)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// LoadMemShift multiplies the first 4 bits of the byte at packet[Off]
+// by 4 and stores the result in register X.
+//
+// This instruction is mainly useful to load into X the length of an
+// IPv4 packet header in a single instruction, rather than have to do
+// the arithmetic on the header's first byte by hand.
+type LoadMemShift struct {
+	Off uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadMemShift) Assemble() (RawInstruction, error) {
+	return assembleLoad(RegX, 1, opAddrModeMemShift, a.Off)
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadMemShift) String() string {
+	return fmt.Sprintf("ldx 4*([%d]&0xf)", a.Off)
+}
+
+// LoadExtension invokes a linux-specific extension and stores the
+// result in register A.
+type LoadExtension struct {
+	Num Extension
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a LoadExtension) Assemble() (RawInstruction, error) {
+	if a.Num == ExtLen {
+		return assembleLoad(RegA, 4, opAddrModePacketLen, 0)
+	}
+	return assembleLoad(RegA, 4, opAddrModeAbsolute, uint32(extOffset+a.Num))
+}
+
+// String returns the instruction in assembler notation.
+func (a LoadExtension) String() string {
+	switch a.Num {
+	case ExtLen:
+		return "ld #len"
+	case ExtProto:
+		return "ld #proto"
+	case ExtType:
+		return "ld #type"
+	case ExtPayloadOffset:
+		return "ld #poff"
+	case ExtInterfaceIndex:
+		return "ld #ifidx"
+	case ExtNetlinkAttr:
+		return "ld #nla"
+	case ExtNetlinkAttrNested:
+		return "ld #nlan"
+	case ExtMark:
+		return "ld #mark"
+	case ExtQueue:
+		return "ld #queue"
+	case ExtLinkLayerType:
+		return "ld #hatype"
+	case ExtRXHash:
+		return "ld #rxhash"
+	case ExtCPUID:
+		return "ld #cpu"
+	case ExtVLANTag:
+		return "ld #vlan_tci"
+	case ExtVLANTagPresent:
+		return "ld #vlan_avail"
+	case ExtVLANProto:
+		return "ld #vlan_tpid"
+	case ExtRand:
+		return "ld #rand"
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// StoreScratch stores register Src into scratch[N].
+type StoreScratch struct {
+	Src Register
+	N   int // 0-15
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a StoreScratch) Assemble() (RawInstruction, error) {
+	if a.N < 0 || a.N > 15 {
+		return RawInstruction{}, fmt.Errorf("invalid scratch slot %d", a.N)
+	}
+	var op uint16
+	switch a.Src {
+	case RegA:
+		op = opClsStoreA
+	case RegX:
+		op = opClsStoreX
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid source register %v", a.Src)
+	}
+
+	return RawInstruction{
+		Op: op,
+		K:  uint32(a.N),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a StoreScratch) String() string {
+	switch a.Src {
+	case RegA:
+		return fmt.Sprintf("st M[%d]", a.N)
+	case RegX:
+		return fmt.Sprintf("stx M[%d]", a.N)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// ALUOpConstant executes A = A <Op> Val.
+type ALUOpConstant struct {
+	Op  ALUOp
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a ALUOpConstant) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | uint16(opOperandConstant) | uint16(a.Op),
+		K:  a.Val,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a ALUOpConstant) String() string {
+	switch a.Op {
+	case ALUOpAdd:
+		return fmt.Sprintf("add #%d", a.Val)
+	case ALUOpSub:
+		return fmt.Sprintf("sub #%d", a.Val)
+	case ALUOpMul:
+		return fmt.Sprintf("mul #%d", a.Val)
+	case ALUOpDiv:
+		return fmt.Sprintf("div #%d", a.Val)
+	case ALUOpMod:
+		return fmt.Sprintf("mod #%d", a.Val)
+	case ALUOpAnd:
+		return fmt.Sprintf("and #%d", a.Val)
+	case ALUOpOr:
+		return fmt.Sprintf("or #%d", a.Val)
+	case ALUOpXor:
+		return fmt.Sprintf("xor #%d", a.Val)
+	case ALUOpShiftLeft:
+		return fmt.Sprintf("lsh #%d", a.Val)
+	case ALUOpShiftRight:
+		return fmt.Sprintf("rsh #%d", a.Val)
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// ALUOpX executes A = A <Op> X
+type ALUOpX struct {
+	Op ALUOp
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a ALUOpX) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | uint16(opOperandX) | uint16(a.Op),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a ALUOpX) String() string {
+	switch a.Op {
+	case ALUOpAdd:
+		return "add x"
+	case ALUOpSub:
+		return "sub x"
+	case ALUOpMul:
+		return "mul x"
+	case ALUOpDiv:
+		return "div x"
+	case ALUOpMod:
+		return "mod x"
+	case ALUOpAnd:
+		return "and x"
+	case ALUOpOr:
+		return "or x"
+	case ALUOpXor:
+		return "xor x"
+	case ALUOpShiftLeft:
+		return "lsh x"
+	case ALUOpShiftRight:
+		return "rsh x"
+	default:
+		return fmt.Sprintf("unknown instruction: %#v", a)
+	}
+}
+
+// NegateA executes A = -A.
+type NegateA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a NegateA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsALU | uint16(aluOpNeg),
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a NegateA) String() string {
+	return fmt.Sprintf("neg")
+}
+
+// Jump skips the following Skip instructions in the program.
+type Jump struct {
+	Skip uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a Jump) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsJump | uint16(opJumpAlways),
+		K:  a.Skip,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a Jump) String() string {
+	return fmt.Sprintf("ja %d", a.Skip)
+}
+
+// JumpIf skips the following Skip instructions in the program if A
+// <Cond> Val is true.
+type JumpIf struct {
+	Cond      JumpTest
+	Val       uint32
+	SkipTrue  uint8
+	SkipFalse uint8
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a JumpIf) Assemble() (RawInstruction, error) {
+	return jumpToRaw(a.Cond, opOperandConstant, a.Val, a.SkipTrue, a.SkipFalse)
+}
+
+// String returns the instruction in assembler notation.
+func (a JumpIf) String() string {
+	return jumpToString(a.Cond, fmt.Sprintf("#%d", a.Val), a.SkipTrue, a.SkipFalse)
+}
+
+// JumpIfX skips the following Skip instructions in the program if A
+// <Cond> X is true.
+type JumpIfX struct {
+	Cond      JumpTest
+	SkipTrue  uint8
+	SkipFalse uint8
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a JumpIfX) Assemble() (RawInstruction, error) {
+	return jumpToRaw(a.Cond, opOperandX, 0, a.SkipTrue, a.SkipFalse)
+}
+
+// String returns the instruction in assembler notation.
+func (a JumpIfX) String() string {
+	return jumpToString(a.Cond, "x", a.SkipTrue, a.SkipFalse)
+}
+
+// jumpToRaw assembles a jump instruction into a RawInstruction
+func jumpToRaw(test JumpTest, operand opOperand, k uint32, skipTrue, skipFalse uint8) (RawInstruction, error) {
+	var (
+		cond jumpOp
+		flip bool
+	)
+	switch test {
+	case JumpEqual:
+		cond = opJumpEqual
+	case JumpNotEqual:
+		cond, flip = opJumpEqual, true
+	case JumpGreaterThan:
+		cond = opJumpGT
+	case JumpLessThan:
+		cond, flip = opJumpGE, true
+	case JumpGreaterOrEqual:
+		cond = opJumpGE
+	case JumpLessOrEqual:
+		cond, flip = opJumpGT, true
+	case JumpBitsSet:
+		cond = opJumpSet
+	case JumpBitsNotSet:
+		cond, flip = opJumpSet, true
+	default:
+		return RawInstruction{}, fmt.Errorf("unknown JumpTest %v", test)
+	}
+	jt, jf := skipTrue, skipFalse
+	if flip {
+		jt, jf = jf, jt
+	}
+	return RawInstruction{
+		Op: opClsJump | uint16(cond) | uint16(operand),
+		Jt: jt,
+		Jf: jf,
+		K:  k,
+	}, nil
+}
+
+// jumpToString converts a jump instruction to assembler notation
+func jumpToString(cond JumpTest, operand string, skipTrue, skipFalse uint8) string {
+	switch cond {
+	// K == A
+	case JumpEqual:
+		return conditionalJump(operand, skipTrue, skipFalse, "jeq", "jneq")
+	// K != A
+	case JumpNotEqual:
+		return fmt.Sprintf("jneq %s,%d", operand, skipTrue)
+	// K > A
+	case JumpGreaterThan:
+		return conditionalJump(operand, skipTrue, skipFalse, "jgt", "jle")
+	// K < A
+	case JumpLessThan:
+		return fmt.Sprintf("jlt %s,%d", operand, skipTrue)
+	// K >= A
+	case JumpGreaterOrEqual:
+		return conditionalJump(operand, skipTrue, skipFalse, "jge", "jlt")
+	// K <= A
+	case JumpLessOrEqual:
+		return fmt.Sprintf("jle %s,%d", operand, skipTrue)
+	// K & A != 0
+	case JumpBitsSet:
+		if skipFalse > 0 {
+			return fmt.Sprintf("jset %s,%d,%d", operand, skipTrue, skipFalse)
+		}
+		return fmt.Sprintf("jset %s,%d", operand, skipTrue)
+	// K & A == 0, there is no assembler instruction for JumpBitNotSet, use JumpBitSet and invert skips
+	case JumpBitsNotSet:
+		return jumpToString(JumpBitsSet, operand, skipFalse, skipTrue)
+	default:
+		return fmt.Sprintf("unknown JumpTest %#v", cond)
+	}
+}
+
+func conditionalJump(operand string, skipTrue, skipFalse uint8, positiveJump, negativeJump string) string {
+	if skipTrue > 0 {
+		if skipFalse > 0 {
+			return fmt.Sprintf("%s %s,%d,%d", positiveJump, operand, skipTrue, skipFalse)
+		}
+		return fmt.Sprintf("%s %s,%d", positiveJump, operand, skipTrue)
+	}
+	return fmt.Sprintf("%s %s,%d", negativeJump, operand, skipFalse)
+}
+
+// RetA exits the BPF program, returning the value of register A.
+type RetA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a RetA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsReturn | opRetSrcA,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a RetA) String() string {
+	return fmt.Sprintf("ret a")
+}
+
+// RetConstant exits the BPF program, returning a constant value.
+type RetConstant struct {
+	Val uint32
+}
+
+// Assemble implements the Instruction Assemble method.
+func (a RetConstant) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsReturn | opRetSrcConstant,
+		K:  a.Val,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a RetConstant) String() string {
+	return fmt.Sprintf("ret #%d", a.Val)
+}
+
+// TXA copies the value of register X to register A.
+type TXA struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a TXA) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsMisc | opMiscTXA,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a TXA) String() string {
+	return fmt.Sprintf("txa")
+}
+
+// TAX copies the value of register A to register X.
+type TAX struct{}
+
+// Assemble implements the Instruction Assemble method.
+func (a TAX) Assemble() (RawInstruction, error) {
+	return RawInstruction{
+		Op: opClsMisc | opMiscTAX,
+	}, nil
+}
+
+// String returns the instruction in assembler notation.
+func (a TAX) String() string {
+	return fmt.Sprintf("tax")
+}
+
+func assembleLoad(dst Register, loadSize int, mode uint16, k uint32) (RawInstruction, error) {
+	var (
+		cls uint16
+		sz  uint16
+	)
+	switch dst {
+	case RegA:
+		cls = opClsLoadA
+	case RegX:
+		cls = opClsLoadX
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid target register %v", dst)
+	}
+	switch loadSize {
+	case 1:
+		sz = opLoadWidth1
+	case 2:
+		sz = opLoadWidth2
+	case 4:
+		sz = opLoadWidth4
+	default:
+		return RawInstruction{}, fmt.Errorf("invalid load byte length %d", sz)
+	}
+	return RawInstruction{
+		Op: cls | sz | mode,
+		K:  k,
+	}, nil
+}
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+// A Setter is a type which can attach a compiled BPF filter to itself.
+type Setter interface {
+	SetBPF(filter []RawInstruction) error
+}
@@ -0,0 +1,150 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+import (
+	"errors"
+	"fmt"
+)
+
+// A VM is an emulated BPF virtual machine.
+type VM struct {
+	filter []Instruction
+}
+
+// NewVM returns a new VM using the input BPF program.
+func NewVM(filter []Instruction) (*VM, error) {
+	if len(filter) == 0 {
+		return nil, errors.New("one or more Instructions must be specified")
+	}
+
+	for i, ins := range filter {
+		check := len(filter) - (i + 1)
+		switch ins := ins.(type) {
+		// Check for out-of-bounds jumps in instructions
+		case Jump:
+			if check <= int(ins.Skip) {
+				return nil, fmt.Errorf("cannot jump %d instructions; jumping past program bounds", ins.Skip)
+			}
+		case JumpIf:
+			if check <= int(ins.SkipTrue) {
+				return nil, fmt.Errorf("cannot jump %d instructions in true case; jumping past program bounds", ins.SkipTrue)
+			}
+			if check <= int(ins.SkipFalse) {
+				return nil, fmt.Errorf("cannot jump %d instructions in false case; jumping past program bounds", ins.SkipFalse)
+			}
+		case JumpIfX:
+			if check <= int(ins.SkipTrue) {
+				return nil, fmt.Errorf("cannot jump %d instructions in true case; jumping past program bounds", ins.SkipTrue)
+			}
+			if check <= int(ins.SkipFalse) {
+				return nil, fmt.Errorf("cannot jump %d instructions in false case; jumping past program bounds", ins.SkipFalse)
+			}
+		// Check for division or modulus by zero
+		case ALUOpConstant:
+			if ins.Val != 0 {
+				break
+			}
+
+			switch ins.Op {
+			case ALUOpDiv, ALUOpMod:
+				return nil, errors.New("cannot divide by zero using ALUOpConstant")
+			}
+		// Check for unknown extensions
+		case LoadExtension:
+			switch ins.Num {
+			case ExtLen:
+			default:
+				return nil, fmt.Errorf("extension %d not implemented", ins.Num)
+			}
+		}
+	}
+
+	// Make sure last instruction is a return instruction
+	switch filter[len(filter)-1].(type) {
+	case RetA, RetConstant:
+	default:
+		return nil, errors.New("BPF program must end with RetA or RetConstant")
+	}
+
+	// Though our VM works using disassembled instructions, we
+	// attempt to assemble the input filter anyway to ensure it is compatible
+	// with an operating system VM.
+	_, err := Assemble(filter)
+
+	return &VM{
+		filter: filter,
+	}, err
+}
+
+// Run runs the VM's BPF program against the input bytes.
+// Run returns the number of bytes accepted by the BPF program, and any errors
+// which occurred while processing the program.
+func (v *VM) Run(in []byte) (int, error) {
+	var (
+		// Registers of the virtual machine
+		regA       uint32
+		regX       uint32
+		regScratch [16]uint32
+
+		// OK is true if the program should continue processing the next
+		// instruction, or false if not, causing the loop to break
+		ok = true
+	)
+
+	// TODO(mdlayher): implement:
+	// - NegateA:
+	//   - would require a change from uint32 registers to int32
+	//     registers
+
+	// TODO(mdlayher): add interop tests that check signedness of ALU
+	// operations against kernel implementation, and make sure Go
+	// implementation matches behavior
+
+	for i := 0; i < len(v.filter) && ok; i++ {
+		ins := v.filter[i]
+
+		switch ins := ins.(type) {
+		case ALUOpConstant:
+			regA = aluOpConstant(ins, regA)
+		case ALUOpX:
+			regA, ok = aluOpX(ins, regA, regX)
+		case Jump:
+			i += int(ins.Skip)
+		case JumpIf:
+			jump := jumpIf(ins, regA)
+			i += jump
+		case JumpIfX:
+			jump := jumpIfX(ins, regA, regX)
+			i += jump
+		case LoadAbsolute:
+			regA, ok = loadAbsolute(ins, in)
+		case LoadConstant:
+			regA, regX = loadConstant(ins, regA, regX)
+		case LoadExtension:
+			regA = loadExtension(ins, in)
+		case LoadIndirect:
+			regA, ok = loadIndirect(ins, in, regX)
+		case LoadMemShift:
+			regX, ok = loadMemShift(ins, in)
+		case LoadScratch:
+			regA, regX = loadScratch(ins, regScratch, regA, regX)
+		case RetA:
+			return int(regA), nil
+		case RetConstant:
+			return int(ins.Val), nil
+		case StoreScratch:
+			regScratch = storeScratch(ins, regScratch, regA, regX)
+		case TAX:
+			regX = regA
+		case TXA:
+			regA = regX
+		default:
+			return 0, fmt.Errorf("unknown Instruction at index %d: %T", i, ins)
+		}
+	}
+
+	return 0, nil
+}
@@ -0,0 +1,182 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bpf
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+func aluOpConstant(ins ALUOpConstant, regA uint32) uint32 {
+	return aluOpCommon(ins.Op, regA, ins.Val)
+}
+
+func aluOpX(ins ALUOpX, regA uint32, regX uint32) (uint32, bool) {
+	// Guard against division or modulus by zero by terminating
+	// the program, as the OS BPF VM does
+	if regX == 0 {
+		switch ins.Op {
+		case ALUOpDiv, ALUOpMod:
+			return 0, false
+		}
+	}
+
+	return aluOpCommon(ins.Op, regA, regX), true
+}
+
+func aluOpCommon(op ALUOp, regA uint32, value uint32) uint32 {
+	switch op {
+	case ALUOpAdd:
+		return regA + value
+	case ALUOpSub:
+		return regA - value
+	case ALUOpMul:
+		return regA * value
+	case ALUOpDiv:
+		// Division by zero not permitted by NewVM and aluOpX checks
+		return regA / value
+	case ALUOpOr:
+		return regA | value
+	case ALUOpAnd:
+		return regA & value
+	case ALUOpShiftLeft:
+		return regA << value
+	case ALUOpShiftRight:
+		return regA >> value
+	case ALUOpMod:
+		// Modulus by zero not permitted by NewVM and aluOpX checks
+		return regA % value
+	case ALUOpXor:
+		return regA ^ value
+	default:
+		return regA
+	}
+}
+
+func jumpIf(ins JumpIf, regA uint32) int {
+	return jumpIfCommon(ins.Cond, ins.SkipTrue, ins.SkipFalse, regA, ins.Val)
+}
+
+func jumpIfX(ins JumpIfX, regA uint32, regX uint32) int {
+	return jumpIfCommon(ins.Cond, ins.SkipTrue, ins.SkipFalse, regA, regX)
+}
+
+func jumpIfCommon(cond JumpTest, skipTrue, skipFalse uint8, regA uint32, value uint32) int {
+	var ok bool
+
+	switch cond {
+	case JumpEqual:
+		ok = regA == value
+	case JumpNotEqual:
+		ok = regA != value
+	case JumpGreaterThan:
+		ok = regA > value
+	case JumpLessThan:
+		ok = regA < value
+	case JumpGreaterOrEqual:
+		ok = regA >= value
+	case JumpLessOrEqual:
+		ok = regA <= value
+	case JumpBitsSet:
+		ok = (regA & value) != 0
+	case JumpBitsNotSet:
+		ok = (regA & value) == 0
+	}
+
+	if ok {
+		return int(skipTrue)
+	}
+
+	return int(skipFalse)
+}
+
+func loadAbsolute(ins LoadAbsolute, in []byte) (uint32, bool) {
+	offset := int(ins.Off)
+	size := ins.Size
+
+	return loadCommon(in, offset, size)
+}
+
+func loadConstant(ins LoadConstant, regA uint32, regX uint32) (uint32, uint32) {
+	switch ins.Dst {
+	case RegA:
+		regA = ins.Val
+	case RegX:
+		regX = ins.Val
+	}
+
+	return regA, regX
+}
+
+func loadExtension(ins LoadExtension, in []byte) uint32 {
+	switch ins.Num {
+	case ExtLen:
+		return uint32(len(in))
+	default:
+		panic(fmt.Sprintf("unimplemented extension: %d", ins.Num))
+	}
+}
+
+func loadIndirect(ins LoadIndirect, in []byte, regX uint32) (uint32, bool) {
+	offset := int(ins.Off) + int(regX)
+	size := ins.Size
+
+	return loadCommon(in, offset, size)
+}
+
+func loadMemShift(ins LoadMemShift, in []byte) (uint32, bool) {
+	offset := int(ins.Off)
+
+	// Size of LoadMemShift is always 1 byte
+	if !inBounds(len(in), offset, 1) {
+		return 0, false
+	}
+
+	// Mask off high 4 bits and multiply low 4 bits by 4
+	return uint32(in[offset]&0x0f) * 4, true
+}
+
+func inBounds(inLen int, offset int, size int) bool {
+	return offset+size <= inLen
+}
+
+func loadCommon(in []byte, offset int, size int) (uint32, bool) {
+	if !inBounds(len(in), offset, size) {
+		return 0, false
+	}
+
+	switch size {
+	case 1:
+		return uint32(in[offset]), true
+	case 2:
+		return uint32(binary.BigEndian.Uint16(in[offset : offset+size])), true
+	case 4:
+		return uint32(binary.BigEndian.Uint32(in[offset : offset+size])), true
+	default:
+		panic(fmt.Sprintf("invalid load size: %d", size))
+	}
+}
+
+func loadScratch(ins LoadScratch, regScratch [16]uint32, regA uint32, regX uint32) (uint32, uint32) {
+	switch ins.Dst {
+	case RegA:
+		regA = regScratch[ins.N]
+	case RegX:
+		regX = regScratch[ins.N]
+	}
+
+	return regA, regX
+}
+
+func storeScratch(ins StoreScratch, regScratch [16]uint32, regA uint32, regX uint32) [16]uint32 {
+	switch ins.Src {
+	case RegA:
+		regScratch[ins.N] = regA
+	case RegX:
+		regScratch[ins.N] = regX
+	}
+
+	return regScratch
+}
@@ -0,0 +1,13 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.18
+
+package idna
+
+// Transitional processing is disabled by default in Go 1.18.
+// https://golang.org/issue/47510
+const transitionalLookup = false
@@ -0,0 +1,769 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.10
+
+// Package idna implements IDNA2008 using the compatibility processing
+// defined by UTS (Unicode Technical Standard) #46, which defines a standard to
+// deal with the transition from IDNA2003.
+//
+// IDNA2008 (Internationalized Domain Names for Applications), is defined in RFC
+// 5890, RFC 5891, RFC 5892, RFC 5893 and RFC 5894.
+// UTS #46 is defined in https://www.unicode.org/reports/tr46.
+// See https://unicode.org/cldr/utility/idna.jsp for a visualization of the
+// differences between these two standards.
+package idna // import "golang.org/x/net/idna"
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/text/secure/bidirule"
+	"golang.org/x/text/unicode/bidi"
+	"golang.org/x/text/unicode/norm"
+)
+
+// NOTE: Unlike common practice in Go APIs, the functions will return a
+// sanitized domain name in case of errors. Browsers sometimes use a partially
+// evaluated string as lookup.
+// TODO: the current error handling is, in my opinion, the least opinionated.
+// Other strategies are also viable, though:
+// Option 1) Return an empty string in case of error, but allow the user to
+//    specify explicitly which errors to ignore.
+// Option 2) Return the partially evaluated string if it is itself a valid
+//    string, otherwise return the empty string in case of error.
+// Option 3) Option 1 and 2.
+// Option 4) Always return an empty string for now and implement Option 1 as
+//    needed, and document that the return string may not be empty in case of
+//    error in the future.
+// I think Option 1 is best, but it is quite opinionated.
+
+// ToASCII is a wrapper for Punycode.ToASCII.
+func ToASCII(s string) (string, error) {
+	return Punycode.process(s, true)
+}
+
+// ToUnicode is a wrapper for Punycode.ToUnicode.
+func ToUnicode(s string) (string, error) {
+	return Punycode.process(s, false)
+}
+
+// An Option configures a Profile at creation time.
+type Option func(*options)
+
+// Transitional sets a Profile to use the Transitional mapping as defined in UTS
+// #46. This will cause, for example, "ß" to be mapped to "ss". Using the
+// transitional mapping provides a compromise between IDNA2003 and IDNA2008
+// compatibility. It is used by some browsers when resolving domain names. This
+// option is only meaningful if combined with MapForLookup.
+func Transitional(transitional bool) Option {
+	return func(o *options) { o.transitional = transitional }
+}
+
+// VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
+// are longer than allowed by the RFC.
+//
+// This option corresponds to the VerifyDnsLength flag in UTS #46.
+func VerifyDNSLength(verify bool) Option {
+	return func(o *options) { o.verifyDNSLength = verify }
+}
+
+// RemoveLeadingDots removes leading label separators. Leading runes that map to
+// dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
+func RemoveLeadingDots(remove bool) Option {
+	return func(o *options) { o.removeLeadingDots = remove }
+}
+
+// ValidateLabels sets whether to check the mandatory label validation criteria
+// as defined in Section 5.4 of RFC 5891. This includes testing for correct use
+// of hyphens ('-'), normalization, validity of runes, and the context rules.
+// In particular, ValidateLabels also sets the CheckHyphens and CheckJoiners flags
+// in UTS #46.
+func ValidateLabels(enable bool) Option {
+	return func(o *options) {
+		// Don't override existing mappings, but set one that at least checks
+		// normalization if it is not set.
+		if o.mapping == nil && enable {
+			o.mapping = normalize
+		}
+		o.trie = trie
+		o.checkJoiners = enable
+		o.checkHyphens = enable
+		if enable {
+			o.fromPuny = validateFromPunycode
+		} else {
+			o.fromPuny = nil
+		}
+	}
+}
+
+// CheckHyphens sets whether to check for correct use of hyphens ('-') in
+// labels. Most web browsers do not have this option set, since labels such as
+// "r3---sn-apo3qvuoxuxbt-j5pe" are in common use.
+//
+// This option corresponds to the CheckHyphens flag in UTS #46.
+func CheckHyphens(enable bool) Option {
+	return func(o *options) { o.checkHyphens = enable }
+}
+
+// CheckJoiners sets whether to check the ContextJ rules as defined in Appendix
+// A of RFC 5892, concerning the use of joiner runes.
+//
+// This option corresponds to the CheckJoiners flag in UTS #46.
+func CheckJoiners(enable bool) Option {
+	return func(o *options) {
+		o.trie = trie
+		o.checkJoiners = enable
+	}
+}
+
+// StrictDomainName limits the set of permissible ASCII characters to those
+// allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
+// hyphen). This is set by default for MapForLookup and ValidateForRegistration,
+// but is only useful if ValidateLabels is set.
+//
+// This option is useful, for instance, for browsers that allow characters
+// outside this range, for example a '_' (U+005F LOW LINE). See
+// http://www.rfc-editor.org/std/std3.txt for more details.
+//
+// This option corresponds to the UseSTD3ASCIIRules flag in UTS #46.
+func StrictDomainName(use bool) Option {
+	return func(o *options) { o.useSTD3Rules = use }
+}
+
+// NOTE: the following options pull in tables. The tables should not be linked
+// in as long as the options are not used.
+
+// BidiRule enables the Bidi rule as defined in RFC 5893. Any application
+// that relies on proper validation of labels should include this rule.
+//
+// This option corresponds to the CheckBidi flag in UTS #46.
+func BidiRule() Option {
+	return func(o *options) { o.bidirule = bidirule.ValidString }
+}
+
+// ValidateForRegistration sets validation options to verify that a given IDN is
+// properly formatted for registration as defined by Section 4 of RFC 5891.
+func ValidateForRegistration() Option {
+	return func(o *options) {
+		o.mapping = validateRegistration
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+		VerifyDNSLength(true)(o)
+		BidiRule()(o)
+	}
+}
+
+// MapForLookup sets validation and mapping options such that a given IDN is
+// transformed for domain name lookup according to the requirements set out in
+// Section 5 of RFC 5891. The mappings follow the recommendations of RFC 5894,
+// RFC 5895 and UTS 46. It does not add the Bidi Rule. Use the BidiRule option
+// to add this check.
+//
+// The mappings include normalization and mapping case, width and other
+// compatibility mappings.
+func MapForLookup() Option {
+	return func(o *options) {
+		o.mapping = validateAndMap
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+	}
+}
+
+type options struct {
+	transitional      bool
+	useSTD3Rules      bool
+	checkHyphens      bool
+	checkJoiners      bool
+	verifyDNSLength   bool
+	removeLeadingDots bool
+
+	trie *idnaTrie
+
+	// fromPuny calls validation rules when converting A-labels to U-labels.
+	fromPuny func(p *Profile, s string) error
+
+	// mapping implements a validation and mapping step as defined in RFC 5895
+	// or UTS 46, tailored to, for example, domain registration or lookup.
+	mapping func(p *Profile, s string) (mapped string, isBidi bool, err error)
+
+	// bidirule, if specified, checks whether s conforms to the Bidi Rule
+	// defined in RFC 5893.
+	bidirule func(s string) bool
+}
+
+// A Profile defines the configuration of an IDNA mapper.
+type Profile struct {
+	options
+}
+
+func apply(o *options, opts []Option) {
+	for _, f := range opts {
+		f(o)
+	}
+}
+
+// New creates a new Profile.
+//
+// With no options, the returned Profile is the most permissive and equals the
+// Punycode Profile. Options can be passed to further restrict the Profile. The
+// MapForLookup and ValidateForRegistration options set a collection of options,
+// for lookup and registration purposes respectively, which can be tailored by
+// adding more fine-grained options, where later options override earlier
+// options.
+func New(o ...Option) *Profile {
+	p := &Profile{}
+	apply(&p.options, o)
+	return p
+}
+
+// ToASCII converts a domain or domain label to its ASCII form. For example,
+// ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
+// ToASCII("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToASCII(s string) (string, error) {
+	return p.process(s, true)
+}
+
+// ToUnicode converts a domain or domain label to its Unicode form. For example,
+// ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and
+// ToUnicode("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToUnicode(s string) (string, error) {
+	pp := *p
+	pp.transitional = false
+	return pp.process(s, false)
+}
+
+// String reports a string with a description of the profile for debugging
+// purposes. The string format may change with different versions.
+func (p *Profile) String() string {
+	s := ""
+	if p.transitional {
+		s = "Transitional"
+	} else {
+		s = "NonTransitional"
+	}
+	if p.useSTD3Rules {
+		s += ":UseSTD3Rules"
+	}
+	if p.checkHyphens {
+		s += ":CheckHyphens"
+	}
+	if p.checkJoiners {
+		s += ":CheckJoiners"
+	}
+	if p.verifyDNSLength {
+		s += ":VerifyDNSLength"
+	}
+	return s
+}
+
+var (
+	// Punycode is a Profile that does raw punycode processing with a minimum
+	// of validation.
+	Punycode *Profile = punycode
+
+	// Lookup is the recommended profile for looking up domain names, according
+	// to Section 5 of RFC 5891. The exact configuration of this profile may
+	// change over time.
+	Lookup *Profile = lookup
+
+	// Display is the recommended profile for displaying domain names.
+	// The configuration of this profile may change over time.
+	Display *Profile = display
+
+	// Registration is the recommended profile for checking whether a given
+	// IDN is valid for registration, according to Section 4 of RFC 5891.
+	Registration *Profile = registration
+
+	punycode = &Profile{}
+	lookup   = &Profile{options{
+		transitional: transitionalLookup,
+		useSTD3Rules: true,
+		checkHyphens: true,
+		checkJoiners: true,
+		trie:         trie,
+		fromPuny:     validateFromPunycode,
+		mapping:      validateAndMap,
+		bidirule:     bidirule.ValidString,
+	}}
+	display = &Profile{options{
+		useSTD3Rules: true,
+		checkHyphens: true,
+		checkJoiners: true,
+		trie:         trie,
+		fromPuny:     validateFromPunycode,
+		mapping:      validateAndMap,
+		bidirule:     bidirule.ValidString,
+	}}
+	registration = &Profile{options{
+		useSTD3Rules:    true,
+		verifyDNSLength: true,
+		checkHyphens:    true,
+		checkJoiners:    true,
+		trie:            trie,
+		fromPuny:        validateFromPunycode,
+		mapping:         validateRegistration,
+		bidirule:        bidirule.ValidString,
+	}}
+
+	// TODO: profiles
+	// Register: recommended for approving domain names: don't do any mappings
+	// but rather reject on invalid input. Bundle or block deviation characters.
+)
+
+type labelError struct{ label, code_ string }
+
+func (e labelError) code() string { return e.code_ }
+func (e labelError) Error() string {
+	return fmt.Sprintf("idna: invalid label %q", e.label)
+}
+
+type runeError rune
+
+func (e runeError) code() string { return "P1" }
+func (e runeError) Error() string {
+	return fmt.Sprintf("idna: disallowed rune %U", e)
+}
+
+// process implements the algorithm described in section 4 of UTS #46,
+// see https://www.unicode.org/reports/tr46.
+func (p *Profile) process(s string, toASCII bool) (string, error) {
+	var err error
+	var isBidi bool
+	if p.mapping != nil {
+		s, isBidi, err = p.mapping(p, s)
+	}
+	// Remove leading empty labels.
+	if p.removeLeadingDots {
+		for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
+		}
+	}
+	// TODO: allow for a quick check of the tables data.
+	// It seems like we should only create this error on ToASCII, but the
+	// UTS 46 conformance tests suggests we should always check this.
+	if err == nil && p.verifyDNSLength && s == "" {
+		err = &labelError{s, "A4"}
+	}
+	labels := labelIter{orig: s}
+	for ; !labels.done(); labels.next() {
+		label := labels.label()
+		if label == "" {
+			// Empty labels are not okay. The label iterator skips the last
+			// label if it is empty.
+			if err == nil && p.verifyDNSLength {
+				err = &labelError{s, "A4"}
+			}
+			continue
+		}
+		if strings.HasPrefix(label, acePrefix) {
+			u, err2 := decode(label[len(acePrefix):])
+			if err2 != nil {
+				if err == nil {
+					err = err2
+				}
+				// Spec says keep the old label.
+				continue
+			}
+			isBidi = isBidi || bidirule.DirectionString(u) != bidi.LeftToRight
+			labels.set(u)
+			if err == nil && p.fromPuny != nil {
+				err = p.fromPuny(p, u)
+			}
+			if err == nil {
+				// This should be called on NonTransitional, according to the
+				// spec, but that currently does not have any effect. Use the
+				// original profile to preserve options.
+				err = p.validateLabel(u)
+			}
+		} else if err == nil {
+			err = p.validateLabel(label)
+		}
+	}
+	if isBidi && p.bidirule != nil && err == nil {
+		for labels.reset(); !labels.done(); labels.next() {
+			if !p.bidirule(labels.label()) {
+				err = &labelError{s, "B"}
+				break
+			}
+		}
+	}
+	if toASCII {
+		for labels.reset(); !labels.done(); labels.next() {
+			label := labels.label()
+			if !ascii(label) {
+				a, err2 := encode(acePrefix, label)
+				if err == nil {
+					err = err2
+				}
+				label = a
+				labels.set(a)
+			}
+			n := len(label)
+			if p.verifyDNSLength && err == nil && (n == 0 || n > 63) {
+				err = &labelError{label, "A4"}
+			}
+		}
+	}
+	s = labels.result()
+	if toASCII && p.verifyDNSLength && err == nil {
+		// Compute the length of the domain name minus the root label and its dot.
+		n := len(s)
+		if n > 0 && s[n-1] == '.' {
+			n--
+		}
+		if len(s) < 1 || n > 253 {
+			err = &labelError{s, "A4"}
+		}
+	}
+	return s, err
+}
+
+func normalize(p *Profile, s string) (mapped string, isBidi bool, err error) {
+	// TODO: consider first doing a quick check to see if any of these checks
+	// need to be done. This will make it slower in the general case, but
+	// faster in the common case.
+	mapped = norm.NFC.String(s)
+	isBidi = bidirule.DirectionString(mapped) == bidi.RightToLeft
+	return mapped, isBidi, nil
+}
+
+func validateRegistration(p *Profile, s string) (idem string, bidi bool, err error) {
+	// TODO: filter need for normalization in loop below.
+	if !norm.NFC.IsNormalString(s) {
+		return s, false, &labelError{s, "V1"}
+	}
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			return s, bidi, runeError(utf8.RuneError)
+		}
+		bidi = bidi || info(v).isBidi(s[i:])
+		// Copy bytes not copied so far.
+		switch p.simplify(info(v).category()) {
+		// TODO: handle the NV8 defined in the Unicode idna data set to allow
+		// for strict conformance to IDNA2008.
+		case valid, deviation:
+		case disallowed, mapped, unknown, ignored:
+			r, _ := utf8.DecodeRuneInString(s[i:])
+			return s, bidi, runeError(r)
+		}
+		i += sz
+	}
+	return s, bidi, nil
+}
+
+func (c info) isBidi(s string) bool {
+	if !c.isMapped() {
+		return c&attributesMask == rtl
+	}
+	// TODO: also store bidi info for mapped data. This is possible, but a bit
+	// cumbersome and not for the common case.
+	p, _ := bidi.LookupString(s)
+	switch p.Class() {
+	case bidi.R, bidi.AL, bidi.AN:
+		return true
+	}
+	return false
+}
+
+func validateAndMap(p *Profile, s string) (vm string, bidi bool, err error) {
+	var (
+		b []byte
+		k int
+	)
+	// combinedInfoBits contains the or-ed bits of all runes. We use this
+	// to derive the mayNeedNorm bit later. This may trigger normalization
+	// overeagerly, but it will not do so in the common case. The end result
+	// is another 10% saving on BenchmarkProfile for the common case.
+	var combinedInfoBits info
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			b = append(b, s[k:i]...)
+			b = append(b, "\ufffd"...)
+			k = len(s)
+			if err == nil {
+				err = runeError(utf8.RuneError)
+			}
+			break
+		}
+		combinedInfoBits |= info(v)
+		bidi = bidi || info(v).isBidi(s[i:])
+		start := i
+		i += sz
+		// Copy bytes not copied so far.
+		switch p.simplify(info(v).category()) {
+		case valid:
+			continue
+		case disallowed:
+			if err == nil {
+				r, _ := utf8.DecodeRuneInString(s[start:])
+				err = runeError(r)
+			}
+			continue
+		case mapped, deviation:
+			b = append(b, s[k:start]...)
+			b = info(v).appendMapping(b, s[start:i])
+		case ignored:
+			b = append(b, s[k:start]...)
+			// drop the rune
+		case unknown:
+			b = append(b, s[k:start]...)
+			b = append(b, "\ufffd"...)
+		}
+		k = i
+	}
+	if k == 0 {
+		// No changes so far.
+		if combinedInfoBits&mayNeedNorm != 0 {
+			s = norm.NFC.String(s)
+		}
+	} else {
+		b = append(b, s[k:]...)
+		if norm.NFC.QuickSpan(b) != len(b) {
+			b = norm.NFC.Bytes(b)
+		}
+		// TODO: the punycode converters require strings as input.
+		s = string(b)
+	}
+	return s, bidi, err
+}
+
+// A labelIter allows iterating over domain name labels.
+type labelIter struct {
+	orig     string
+	slice    []string
+	curStart int
+	curEnd   int
+	i        int
+}
+
+func (l *labelIter) reset() {
+	l.curStart = 0
+	l.curEnd = 0
+	l.i = 0
+}
+
+func (l *labelIter) done() bool {
+	return l.curStart >= len(l.orig)
+}
+
+func (l *labelIter) result() string {
+	if l.slice != nil {
+		return strings.Join(l.slice, ".")
+	}
+	return l.orig
+}
+
+func (l *labelIter) label() string {
+	if l.slice != nil {
+		return l.slice[l.i]
+	}
+	p := strings.IndexByte(l.orig[l.curStart:], '.')
+	l.curEnd = l.curStart + p
+	if p == -1 {
+		l.curEnd = len(l.orig)
+	}
+	return l.orig[l.curStart:l.curEnd]
+}
+
+// next sets the value to the next label. It skips the last label if it is empty.
+func (l *labelIter) next() {
+	l.i++
+	if l.slice != nil {
+		if l.i >= len(l.slice) || l.i == len(l.slice)-1 && l.slice[l.i] == "" {
+			l.curStart = len(l.orig)
+		}
+	} else {
+		l.curStart = l.curEnd + 1
+		if l.curStart == len(l.orig)-1 && l.orig[l.curStart] == '.' {
+			l.curStart = len(l.orig)
+		}
+	}
+}
+
+func (l *labelIter) set(s string) {
+	if l.slice == nil {
+		l.slice = strings.Split(l.orig, ".")
+	}
+	l.slice[l.i] = s
+}
+
+// acePrefix is the ASCII Compatible Encoding prefix.
+const acePrefix = "xn--"
+
+func (p *Profile) simplify(cat category) category {
+	switch cat {
+	case disallowedSTD3Mapped:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = mapped
+		}
+	case disallowedSTD3Valid:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = valid
+		}
+	case deviation:
+		if !p.transitional {
+			cat = valid
+		}
+	case validNV8, validXV8:
+		// TODO: handle V2008
+		cat = valid
+	}
+	return cat
+}
+
+func validateFromPunycode(p *Profile, s string) error {
+	if !norm.NFC.IsNormalString(s) {
+		return &labelError{s, "V1"}
+	}
+	// TODO: detect whether string may have to be normalized in the following
+	// loop.
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			return runeError(utf8.RuneError)
+		}
+		if c := p.simplify(info(v).category()); c != valid && c != deviation {
+			return &labelError{s, "V6"}
+		}
+		i += sz
+	}
+	return nil
+}
+
+const (
+	zwnj = "\u200c"
+	zwj  = "\u200d"
+)
+
+type joinState int8
+
+const (
+	stateStart joinState = iota
+	stateVirama
+	stateBefore
+	stateBeforeVirama
+	stateAfter
+	stateFAIL
+)
+
+var joinStates = [][numJoinTypes]joinState{
+	stateStart: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateVirama,
+	},
+	stateVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+	},
+	stateBefore: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joiningT:   stateBefore,
+		joinZWNJ:   stateAfter,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateBeforeVirama,
+	},
+	stateBeforeVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+		joiningT: stateBefore,
+	},
+	stateAfter: {
+		joiningL:   stateFAIL,
+		joiningD:   stateBefore,
+		joiningT:   stateAfter,
+		joiningR:   stateStart,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateAfter, // no-op as we can't accept joiners here
+	},
+	stateFAIL: {
+		0:          stateFAIL,
+		joiningL:   stateFAIL,
+		joiningD:   stateFAIL,
+		joiningT:   stateFAIL,
+		joiningR:   stateFAIL,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateFAIL,
+	},
+}
+
+// validateLabel validates the criteria from Section 4.1. Item 1, 4, and 6 are
+// already implicitly satisfied by the overall implementation.
+func (p *Profile) validateLabel(s string) (err error) {
+	if s == "" {
+		if p.verifyDNSLength {
+			return &labelError{s, "A4"}
+		}
+		return nil
+	}
+	if p.checkHyphens {
+		if len(s) > 4 && s[2] == '-' && s[3] == '-' {
+			return &labelError{s, "V2"}
+		}
+		if s[0] == '-' || s[len(s)-1] == '-' {
+			return &labelError{s, "V3"}
+		}
+	}
+	if !p.checkJoiners {
+		return nil
+	}
+	trie := p.trie // p.checkJoiners is only set if trie is set.
+	// TODO: merge the use of this in the trie.
+	v, sz := trie.lookupString(s)
+	x := info(v)
+	if x.isModifier() {
+		return &labelError{s, "V5"}
+	}
+	// Quickly return in the absence of zero-width (non) joiners.
+	if strings.Index(s, zwj) == -1 && strings.Index(s, zwnj) == -1 {
+		return nil
+	}
+	st := stateStart
+	for i := 0; ; {
+		jt := x.joinType()
+		if s[i:i+sz] == zwj {
+			jt = joinZWJ
+		} else if s[i:i+sz] == zwnj {
+			jt = joinZWNJ
+		}
+		st = joinStates[st][jt]
+		if x.isViramaModifier() {
+			st = joinStates[st][joinVirama]
+		}
+		if i += sz; i == len(s) {
+			break
+		}
+		v, sz = trie.lookupString(s[i:])
+		x = info(v)
+	}
+	if st == stateFAIL || st == stateAfter {
+		return &labelError{s, "C"}
+	}
+	return nil
+}
+
+func ascii(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return false
+		}
+	}
+	return true
+}
@@ -0,0 +1,717 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.10
+
+// Package idna implements IDNA2008 using the compatibility processing
+// defined by UTS (Unicode Technical Standard) #46, which defines a standard to
+// deal with the transition from IDNA2003.
+//
+// IDNA2008 (Internationalized Domain Names for Applications), is defined in RFC
+// 5890, RFC 5891, RFC 5892, RFC 5893 and RFC 5894.
+// UTS #46 is defined in https://www.unicode.org/reports/tr46.
+// See https://unicode.org/cldr/utility/idna.jsp for a visualization of the
+// differences between these two standards.
+package idna // import "golang.org/x/net/idna"
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/text/secure/bidirule"
+	"golang.org/x/text/unicode/norm"
+)
+
+// NOTE: Unlike common practice in Go APIs, the functions will return a
+// sanitized domain name in case of errors. Browsers sometimes use a partially
+// evaluated string as lookup.
+// TODO: the current error handling is, in my opinion, the least opinionated.
+// Other strategies are also viable, though:
+// Option 1) Return an empty string in case of error, but allow the user to
+//    specify explicitly which errors to ignore.
+// Option 2) Return the partially evaluated string if it is itself a valid
+//    string, otherwise return the empty string in case of error.
+// Option 3) Option 1 and 2.
+// Option 4) Always return an empty string for now and implement Option 1 as
+//    needed, and document that the return string may not be empty in case of
+//    error in the future.
+// I think Option 1 is best, but it is quite opinionated.
+
+// ToASCII is a wrapper for Punycode.ToASCII.
+func ToASCII(s string) (string, error) {
+	return Punycode.process(s, true)
+}
+
+// ToUnicode is a wrapper for Punycode.ToUnicode.
+func ToUnicode(s string) (string, error) {
+	return Punycode.process(s, false)
+}
+
+// An Option configures a Profile at creation time.
+type Option func(*options)
+
+// Transitional sets a Profile to use the Transitional mapping as defined in UTS
+// #46. This will cause, for example, "ß" to be mapped to "ss". Using the
+// transitional mapping provides a compromise between IDNA2003 and IDNA2008
+// compatibility. It is used by some browsers when resolving domain names. This
+// option is only meaningful if combined with MapForLookup.
+func Transitional(transitional bool) Option {
+	return func(o *options) { o.transitional = transitional }
+}
+
+// VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
+// are longer than allowed by the RFC.
+//
+// This option corresponds to the VerifyDnsLength flag in UTS #46.
+func VerifyDNSLength(verify bool) Option {
+	return func(o *options) { o.verifyDNSLength = verify }
+}
+
+// RemoveLeadingDots removes leading label separators. Leading runes that map to
+// dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
+func RemoveLeadingDots(remove bool) Option {
+	return func(o *options) { o.removeLeadingDots = remove }
+}
+
+// ValidateLabels sets whether to check the mandatory label validation criteria
+// as defined in Section 5.4 of RFC 5891. This includes testing for correct use
+// of hyphens ('-'), normalization, validity of runes, and the context rules.
+// In particular, ValidateLabels also sets the CheckHyphens and CheckJoiners flags
+// in UTS #46.
+func ValidateLabels(enable bool) Option {
+	return func(o *options) {
+		// Don't override existing mappings, but set one that at least checks
+		// normalization if it is not set.
+		if o.mapping == nil && enable {
+			o.mapping = normalize
+		}
+		o.trie = trie
+		o.checkJoiners = enable
+		o.checkHyphens = enable
+		if enable {
+			o.fromPuny = validateFromPunycode
+		} else {
+			o.fromPuny = nil
+		}
+	}
+}
+
+// CheckHyphens sets whether to check for correct use of hyphens ('-') in
+// labels. Most web browsers do not have this option set, since labels such as
+// "r3---sn-apo3qvuoxuxbt-j5pe" are in common use.
+//
+// This option corresponds to the CheckHyphens flag in UTS #46.
+func CheckHyphens(enable bool) Option {
+	return func(o *options) { o.checkHyphens = enable }
+}
+
+// CheckJoiners sets whether to check the ContextJ rules as defined in Appendix
+// A of RFC 5892, concerning the use of joiner runes.
+//
+// This option corresponds to the CheckJoiners flag in UTS #46.
+func CheckJoiners(enable bool) Option {
+	return func(o *options) {
+		o.trie = trie
+		o.checkJoiners = enable
+	}
+}
+
+// StrictDomainName limits the set of permissible ASCII characters to those
+// allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
+// hyphen). This is set by default for MapForLookup and ValidateForRegistration,
+// but is only useful if ValidateLabels is set.
+//
+// This option is useful, for instance, for browsers that allow characters
+// outside this range, for example a '_' (U+005F LOW LINE). See
+// http://www.rfc-editor.org/std/std3.txt for more details.
+//
+// This option corresponds to the UseSTD3ASCIIRules flag in UTS #46.
+func StrictDomainName(use bool) Option {
+	return func(o *options) { o.useSTD3Rules = use }
+}
+
+// NOTE: the following options pull in tables. The tables should not be linked
+// in as long as the options are not used.
+
+// BidiRule enables the Bidi rule as defined in RFC 5893. Any application
+// that relies on proper validation of labels should include this rule.
+//
+// This option corresponds to the CheckBidi flag in UTS #46.
+func BidiRule() Option {
+	return func(o *options) { o.bidirule = bidirule.ValidString }
+}
+
+// ValidateForRegistration sets validation options to verify that a given IDN is
+// properly formatted for registration as defined by Section 4 of RFC 5891.
+func ValidateForRegistration() Option {
+	return func(o *options) {
+		o.mapping = validateRegistration
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+		VerifyDNSLength(true)(o)
+		BidiRule()(o)
+	}
+}
+
+// MapForLookup sets validation and mapping options such that a given IDN is
+// transformed for domain name lookup according to the requirements set out in
+// Section 5 of RFC 5891. The mappings follow the recommendations of RFC 5894,
+// RFC 5895 and UTS 46. It does not add the Bidi Rule. Use the BidiRule option
+// to add this check.
+//
+// The mappings include normalization and mapping case, width and other
+// compatibility mappings.
+func MapForLookup() Option {
+	return func(o *options) {
+		o.mapping = validateAndMap
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+		RemoveLeadingDots(true)(o)
+	}
+}
+
+type options struct {
+	transitional      bool
+	useSTD3Rules      bool
+	checkHyphens      bool
+	checkJoiners      bool
+	verifyDNSLength   bool
+	removeLeadingDots bool
+
+	trie *idnaTrie
+
+	// fromPuny calls validation rules when converting A-labels to U-labels.
+	fromPuny func(p *Profile, s string) error
+
+	// mapping implements a validation and mapping step as defined in RFC 5895
+	// or UTS 46, tailored to, for example, domain registration or lookup.
+	mapping func(p *Profile, s string) (string, error)
+
+	// bidirule, if specified, checks whether s conforms to the Bidi Rule
+	// defined in RFC 5893.
+	bidirule func(s string) bool
+}
+
+// A Profile defines the configuration of a IDNA mapper.
+type Profile struct {
+	options
+}
+
+func apply(o *options, opts []Option) {
+	for _, f := range opts {
+		f(o)
+	}
+}
+
+// New creates a new Profile.
+//
+// With no options, the returned Profile is the most permissive and equals the
+// Punycode Profile. Options can be passed to further restrict the Profile. The
+// MapForLookup and ValidateForRegistration options set a collection of options,
+// for lookup and registration purposes respectively, which can be tailored by
+// adding more fine-grained options, where later options override earlier
+// options.
+func New(o ...Option) *Profile {
+	p := &Profile{}
+	apply(&p.options, o)
+	return p
+}
+
+// ToASCII converts a domain or domain label to its ASCII form. For example,
+// ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
+// ToASCII("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToASCII(s string) (string, error) {
+	return p.process(s, true)
+}
+
+// ToUnicode converts a domain or domain label to its Unicode form. For example,
+// ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and
+// ToUnicode("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToUnicode(s string) (string, error) {
+	pp := *p
+	pp.transitional = false
+	return pp.process(s, false)
+}
+
+// String reports a string with a description of the profile for debugging
+// purposes. The string format may change with different versions.
+func (p *Profile) String() string {
+	s := ""
+	if p.transitional {
+		s = "Transitional"
+	} else {
+		s = "NonTransitional"
+	}
+	if p.useSTD3Rules {
+		s += ":UseSTD3Rules"
+	}
+	if p.checkHyphens {
+		s += ":CheckHyphens"
+	}
+	if p.checkJoiners {
+		s += ":CheckJoiners"
+	}
+	if p.verifyDNSLength {
+		s += ":VerifyDNSLength"
+	}
+	return s
+}
+
+var (
+	// Punycode is a Profile that does raw punycode processing with a minimum
+	// of validation.
+	Punycode *Profile = punycode
+
+	// Lookup is the recommended profile for looking up domain names, according
+	// to Section 5 of RFC 5891. The exact configuration of this profile may
+	// change over time.
+	Lookup *Profile = lookup
+
+	// Display is the recommended profile for displaying domain names.
+	// The configuration of this profile may change over time.
+	Display *Profile = display
+
+	// Registration is the recommended profile for checking whether a given
+	// IDN is valid for registration, according to Section 4 of RFC 5891.
+	Registration *Profile = registration
+
+	punycode = &Profile{}
+	lookup   = &Profile{options{
+		transitional:      true,
+		removeLeadingDots: true,
+		useSTD3Rules:      true,
+		checkHyphens:      true,
+		checkJoiners:      true,
+		trie:              trie,
+		fromPuny:          validateFromPunycode,
+		mapping:           validateAndMap,
+		bidirule:          bidirule.ValidString,
+	}}
+	display = &Profile{options{
+		useSTD3Rules:      true,
+		removeLeadingDots: true,
+		checkHyphens:      true,
+		checkJoiners:      true,
+		trie:              trie,
+		fromPuny:          validateFromPunycode,
+		mapping:           validateAndMap,
+		bidirule:          bidirule.ValidString,
+	}}
+	registration = &Profile{options{
+		useSTD3Rules:    true,
+		verifyDNSLength: true,
+		checkHyphens:    true,
+		checkJoiners:    true,
+		trie:            trie,
+		fromPuny:        validateFromPunycode,
+		mapping:         validateRegistration,
+		bidirule:        bidirule.ValidString,
+	}}
+
+	// TODO: profiles
+	// Register: recommended for approving domain names: don't do any mappings
+	// but rather reject on invalid input. Bundle or block deviation characters.
+)
+
+type labelError struct{ label, code_ string }
+
+func (e labelError) code() string { return e.code_ }
+func (e labelError) Error() string {
+	return fmt.Sprintf("idna: invalid label %q", e.label)
+}
+
+type runeError rune
+
+func (e runeError) code() string { return "P1" }
+func (e runeError) Error() string {
+	return fmt.Sprintf("idna: disallowed rune %U", e)
+}
+
+// process implements the algorithm described in section 4 of UTS #46,
+// see https://www.unicode.org/reports/tr46.
+func (p *Profile) process(s string, toASCII bool) (string, error) {
+	var err error
+	if p.mapping != nil {
+		s, err = p.mapping(p, s)
+	}
+	// Remove leading empty labels.
+	if p.removeLeadingDots {
+		for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
+		}
+	}
+	// It seems like we should only create this error on ToASCII, but the
+	// UTS 46 conformance tests suggests we should always check this.
+	if err == nil && p.verifyDNSLength && s == "" {
+		err = &labelError{s, "A4"}
+	}
+	labels := labelIter{orig: s}
+	for ; !labels.done(); labels.next() {
+		label := labels.label()
+		if label == "" {
+			// Empty labels are not okay. The label iterator skips the last
+			// label if it is empty.
+			if err == nil && p.verifyDNSLength {
+				err = &labelError{s, "A4"}
+			}
+			continue
+		}
+		if strings.HasPrefix(label, acePrefix) {
+			u, err2 := decode(label[len(acePrefix):])
+			if err2 != nil {
+				if err == nil {
+					err = err2
+				}
+				// Spec says keep the old label.
+				continue
+			}
+			labels.set(u)
+			if err == nil && p.fromPuny != nil {
+				err = p.fromPuny(p, u)
+			}
+			if err == nil {
+				// This should be called on NonTransitional, according to the
+				// spec, but that currently does not have any effect. Use the
+				// original profile to preserve options.
+				err = p.validateLabel(u)
+			}
+		} else if err == nil {
+			err = p.validateLabel(label)
+		}
+	}
+	if toASCII {
+		for labels.reset(); !labels.done(); labels.next() {
+			label := labels.label()
+			if !ascii(label) {
+				a, err2 := encode(acePrefix, label)
+				if err == nil {
+					err = err2
+				}
+				label = a
+				labels.set(a)
+			}
+			n := len(label)
+			if p.verifyDNSLength && err == nil && (n == 0 || n > 63) {
+				err = &labelError{label, "A4"}
+			}
+		}
+	}
+	s = labels.result()
+	if toASCII && p.verifyDNSLength && err == nil {
+		// Compute the length of the domain name minus the root label and its dot.
+		n := len(s)
+		if n > 0 && s[n-1] == '.' {
+			n--
+		}
+		if len(s) < 1 || n > 253 {
+			err = &labelError{s, "A4"}
+		}
+	}
+	return s, err
+}
+
+func normalize(p *Profile, s string) (string, error) {
+	return norm.NFC.String(s), nil
+}
+
+func validateRegistration(p *Profile, s string) (string, error) {
+	if !norm.NFC.IsNormalString(s) {
+		return s, &labelError{s, "V1"}
+	}
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		// Copy bytes not copied so far.
+		switch p.simplify(info(v).category()) {
+		// TODO: handle the NV8 defined in the Unicode idna data set to allow
+		// for strict conformance to IDNA2008.
+		case valid, deviation:
+		case disallowed, mapped, unknown, ignored:
+			r, _ := utf8.DecodeRuneInString(s[i:])
+			return s, runeError(r)
+		}
+		i += sz
+	}
+	return s, nil
+}
+
+func validateAndMap(p *Profile, s string) (string, error) {
+	var (
+		err error
+		b   []byte
+		k   int
+	)
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		start := i
+		i += sz
+		// Copy bytes not copied so far.
+		switch p.simplify(info(v).category()) {
+		case valid:
+			continue
+		case disallowed:
+			if err == nil {
+				r, _ := utf8.DecodeRuneInString(s[start:])
+				err = runeError(r)
+			}
+			continue
+		case mapped, deviation:
+			b = append(b, s[k:start]...)
+			b = info(v).appendMapping(b, s[start:i])
+		case ignored:
+			b = append(b, s[k:start]...)
+			// drop the rune
+		case unknown:
+			b = append(b, s[k:start]...)
+			b = append(b, "\ufffd"...)
+		}
+		k = i
+	}
+	if k == 0 {
+		// No changes so far.
+		s = norm.NFC.String(s)
+	} else {
+		b = append(b, s[k:]...)
+		if norm.NFC.QuickSpan(b) != len(b) {
+			b = norm.NFC.Bytes(b)
+		}
+		// TODO: the punycode converters require strings as input.
+		s = string(b)
+	}
+	return s, err
+}
+
+// A labelIter allows iterating over domain name labels.
+type labelIter struct {
+	orig     string
+	slice    []string
+	curStart int
+	curEnd   int
+	i        int
+}
+
+func (l *labelIter) reset() {
+	l.curStart = 0
+	l.curEnd = 0
+	l.i = 0
+}
+
+func (l *labelIter) done() bool {
+	return l.curStart >= len(l.orig)
+}
+
+func (l *labelIter) result() string {
+	if l.slice != nil {
+		return strings.Join(l.slice, ".")
+	}
+	return l.orig
+}
+
+func (l *labelIter) label() string {
+	if l.slice != nil {
+		return l.slice[l.i]
+	}
+	p := strings.IndexByte(l.orig[l.curStart:], '.')
+	l.curEnd = l.curStart + p
+	if p == -1 {
+		l.curEnd = len(l.orig)
+	}
+	return l.orig[l.curStart:l.curEnd]
+}
+
+// next sets the value to the next label. It skips the last label if it is empty.
+func (l *labelIter) next() {
+	l.i++
+	if l.slice != nil {
+		if l.i >= len(l.slice) || l.i == len(l.slice)-1 && l.slice[l.i] == "" {
+			l.curStart = len(l.orig)
+		}
+	} else {
+		l.curStart = l.curEnd + 1
+		if l.curStart == len(l.orig)-1 && l.orig[l.curStart] == '.' {
+			l.curStart = len(l.orig)
+		}
+	}
+}
+
+func (l *labelIter) set(s string) {
+	if l.slice == nil {
+		l.slice = strings.Split(l.orig, ".")
+	}
+	l.slice[l.i] = s
+}
+
+// acePrefix is the ASCII Compatible Encoding prefix.
+const acePrefix = "xn--"
+
+func (p *Profile) simplify(cat category) category {
+	switch cat {
+	case disallowedSTD3Mapped:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = mapped
+		}
+	case disallowedSTD3Valid:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = valid
+		}
+	case deviation:
+		if !p.transitional {
+			cat = valid
+		}
+	case validNV8, validXV8:
+		// TODO: handle V2008
+		cat = valid
+	}
+	return cat
+}
+
+func validateFromPunycode(p *Profile, s string) error {
+	if !norm.NFC.IsNormalString(s) {
+		return &labelError{s, "V1"}
+	}
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if c := p.simplify(info(v).category()); c != valid && c != deviation {
+			return &labelError{s, "V6"}
+		}
+		i += sz
+	}
+	return nil
+}
+
+const (
+	zwnj = "\u200c"
+	zwj  = "\u200d"
+)
+
+type joinState int8
+
+const (
+	stateStart joinState = iota
+	stateVirama
+	stateBefore
+	stateBeforeVirama
+	stateAfter
+	stateFAIL
+)
+
+var joinStates = [][numJoinTypes]joinState{
+	stateStart: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateVirama,
+	},
+	stateVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+	},
+	stateBefore: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joiningT:   stateBefore,
+		joinZWNJ:   stateAfter,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateBeforeVirama,
+	},
+	stateBeforeVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+		joiningT: stateBefore,
+	},
+	stateAfter: {
+		joiningL:   stateFAIL,
+		joiningD:   stateBefore,
+		joiningT:   stateAfter,
+		joiningR:   stateStart,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateAfter, // no-op as we can't accept joiners here
+	},
+	stateFAIL: {
+		0:          stateFAIL,
+		joiningL:   stateFAIL,
+		joiningD:   stateFAIL,
+		joiningT:   stateFAIL,
+		joiningR:   stateFAIL,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateFAIL,
+	},
+}
+
+// validateLabel validates the criteria from Section 4.1. Item 1, 4, and 6 are
+// already implicitly satisfied by the overall implementation.
+func (p *Profile) validateLabel(s string) error {
+	if s == "" {
+		if p.verifyDNSLength {
+			return &labelError{s, "A4"}
+		}
+		return nil
+	}
+	if p.bidirule != nil && !p.bidirule(s) {
+		return &labelError{s, "B"}
+	}
+	if p.checkHyphens {
+		if len(s) > 4 && s[2] == '-' && s[3] == '-' {
+			return &labelError{s, "V2"}
+		}
+		if s[0] == '-' || s[len(s)-1] == '-' {
+			return &labelError{s, "V3"}
+		}
+	}
+	if !p.checkJoiners {
+		return nil
+	}
+	trie := p.trie // p.checkJoiners is only set if trie is set.
+	// TODO: merge the use of this in the trie.
+	v, sz := trie.lookupString(s)
+	x := info(v)
+	if x.isModifier() {
+		return &labelError{s, "V5"}
+	}
+	// Quickly return in the absence of zero-width (non) joiners.
+	if strings.Index(s, zwj) == -1 && strings.Index(s, zwnj) == -1 {
+		return nil
+	}
+	st := stateStart
+	for i := 0; ; {
+		jt := x.joinType()
+		if s[i:i+sz] == zwj {
+			jt = joinZWJ
+		} else if s[i:i+sz] == zwnj {
+			jt = joinZWNJ
+		}
+		st = joinStates[st][jt]
+		if x.isViramaModifier() {
+			st = joinStates[st][joinVirama]
+		}
+		if i += sz; i == len(s) {
+			break
+		}
+		v, sz = trie.lookupString(s[i:])
+		x = info(v)
+	}
+	if st == stateFAIL || st == stateAfter {
+		return &labelError{s, "C"}
+	}
+	return nil
+}
+
+func ascii(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return false
+		}
+	}
+	return true
+}
@@ -0,0 +1,11 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.18
+
+package idna
+
+const transitionalLookup = true
@@ -0,0 +1,217 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package idna
+
+// This file implements the Punycode algorithm from RFC 3492.
+
+import (
+	"math"
+	"strings"
+	"unicode/utf8"
+)
+
+// These parameter values are specified in section 5.
+//
+// All computation is done with int32s, so that overflow behavior is identical
+// regardless of whether int is 32-bit or 64-bit.
+const (
+	base        int32 = 36
+	damp        int32 = 700
+	initialBias int32 = 72
+	initialN    int32 = 128
+	skew        int32 = 38
+	tmax        int32 = 26
+	tmin        int32 = 1
+)
+
+func punyError(s string) error { return &labelError{s, "A3"} }
+
+// decode decodes a string as specified in section 6.2.
+func decode(encoded string) (string, error) {
+	if encoded == "" {
+		return "", nil
+	}
+	pos := 1 + strings.LastIndex(encoded, "-")
+	if pos == 1 {
+		return "", punyError(encoded)
+	}
+	if pos == len(encoded) {
+		return encoded[:len(encoded)-1], nil
+	}
+	output := make([]rune, 0, len(encoded))
+	if pos != 0 {
+		for _, r := range encoded[:pos-1] {
+			output = append(output, r)
+		}
+	}
+	i, n, bias := int32(0), initialN, initialBias
+	overflow := false
+	for pos < len(encoded) {
+		oldI, w := i, int32(1)
+		for k := base; ; k += base {
+			if pos == len(encoded) {
+				return "", punyError(encoded)
+			}
+			digit, ok := decodeDigit(encoded[pos])
+			if !ok {
+				return "", punyError(encoded)
+			}
+			pos++
+			i, overflow = madd(i, digit, w)
+			if overflow {
+				return "", punyError(encoded)
+			}
+			t := k - bias
+			if k <= bias {
+				t = tmin
+			} else if k >= bias+tmax {
+				t = tmax
+			}
+			if digit < t {
+				break
+			}
+			w, overflow = madd(0, w, base-t)
+			if overflow {
+				return "", punyError(encoded)
+			}
+		}
+		if len(output) >= 1024 {
+			return "", punyError(encoded)
+		}
+		x := int32(len(output) + 1)
+		bias = adapt(i-oldI, x, oldI == 0)
+		n += i / x
+		i %= x
+		if n < 0 || n > utf8.MaxRune {
+			return "", punyError(encoded)
+		}
+		output = append(output, 0)
+		copy(output[i+1:], output[i:])
+		output[i] = n
+		i++
+	}
+	return string(output), nil
+}
+
+// encode encodes a string as specified in section 6.3 and prepends prefix to
+// the result.
+//
+// The "while h < length(input)" line in the specification becomes "for
+// remaining != 0" in the Go code, because len(s) in Go is in bytes, not runes.
+func encode(prefix, s string) (string, error) {
+	output := make([]byte, len(prefix), len(prefix)+1+2*len(s))
+	copy(output, prefix)
+	delta, n, bias := int32(0), initialN, initialBias
+	b, remaining := int32(0), int32(0)
+	for _, r := range s {
+		if r < 0x80 {
+			b++
+			output = append(output, byte(r))
+		} else {
+			remaining++
+		}
+	}
+	h := b
+	if b > 0 {
+		output = append(output, '-')
+	}
+	overflow := false
+	for remaining != 0 {
+		m := int32(0x7fffffff)
+		for _, r := range s {
+			if m > r && r >= n {
+				m = r
+			}
+		}
+		delta, overflow = madd(delta, m-n, h+1)
+		if overflow {
+			return "", punyError(s)
+		}
+		n = m
+		for _, r := range s {
+			if r < n {
+				delta++
+				if delta < 0 {
+					return "", punyError(s)
+				}
+				continue
+			}
+			if r > n {
+				continue
+			}
+			q := delta
+			for k := base; ; k += base {
+				t := k - bias
+				if k <= bias {
+					t = tmin
+				} else if k >= bias+tmax {
+					t = tmax
+				}
+				if q < t {
+					break
+				}
+				output = append(output, encodeDigit(t+(q-t)%(base-t)))
+				q = (q - t) / (base - t)
+			}
+			output = append(output, encodeDigit(q))
+			bias = adapt(delta, h+1, h == b)
+			delta = 0
+			h++
+			remaining--
+		}
+		delta++
+		n++
+	}
+	return string(output), nil
+}
+
+// madd computes a + (b * c), detecting overflow.
+func madd(a, b, c int32) (next int32, overflow bool) {
+	p := int64(b) * int64(c)
+	if p > math.MaxInt32-int64(a) {
+		return 0, true
+	}
+	return a + int32(p), false
+}
+
+func decodeDigit(x byte) (digit int32, ok bool) {
+	switch {
+	case '0' <= x && x <= '9':
+		return int32(x - ('0' - 26)), true
+	case 'A' <= x && x <= 'Z':
+		return int32(x - 'A'), true
+	case 'a' <= x && x <= 'z':
+		return int32(x - 'a'), true
+	}
+	return 0, false
+}
+
+func encodeDigit(digit int32) byte {
+	switch {
+	case 0 <= digit && digit < 26:
+		return byte(digit + 'a')
+	case 26 <= digit && digit < 36:
+		return byte(digit + ('0' - 26))
+	}
+	panic("idna: internal error in punycode encoding")
+}
+
+// adapt is the bias adaptation function specified in section 6.1.
+func adapt(delta, numPoints int32, firstTime bool) int32 {
+	if firstTime {
+		delta /= damp
+	} else {
+		delta /= 2
+	}
+	delta += delta / numPoints
+	k := int32(0)
+	for delta > ((base-tmin)*tmax)/2 {
+		delta /= base - tmin
+		k += base
+	}
+	return k + (base-tmin+1)*delta/(delta+skew)
+}
@@ -0,0 +1,51 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package idna
+
+// Sparse block handling code.
+
+type valueRange struct {
+	value  uint16 // header: value:stride
+	lo, hi byte   // header: lo:n
+}
+
+type sparseBlocks struct {
+	values []valueRange
+	offset []uint16
+}
+
+var idnaSparse = sparseBlocks{
+	values: idnaSparseValues[:],
+	offset: idnaSparseOffset[:],
+}
+
+// Don't use newIdnaTrie to avoid unconditional linking in of the table.
+var trie = &idnaTrie{}
+
+// lookup determines the type of block n and looks up the value for b.
+// For n < t.cutoff, the block is a simple lookup table. Otherwise, the block
+// is a list of ranges with an accompanying value. Given a matching range r,
+// the value for b is by r.value + (b - r.lo) * stride.
+func (t *sparseBlocks) lookup(n uint32, b byte) uint16 {
+	offset := t.offset[n]
+	header := t.values[offset]
+	lo := offset + 1
+	hi := lo + uint16(header.lo)
+	for lo < hi {
+		m := lo + (hi-lo)/2
+		r := t.values[m]
+		if r.lo <= b && b <= r.hi {
+			return r.value + uint16(b-r.lo)*header.value
+		}
+		if b < r.lo {
+			hi = m
+		} else {
+			lo = m + 1
+		}
+	}
+	return 0
+}
@@ -0,0 +1,30 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !go1.16
+
+package idna
+
+// appendMapping appends the mapping for the respective rune. isMapped must be
+// true. A mapping is a categorization of a rune as defined in UTS #46.
+func (c info) appendMapping(b []byte, s string) []byte {
+	index := int(c >> indexShift)
+	if c&xorBit == 0 {
+		s := mappings[index:]
+		return append(b, s[1:s[0]+1]...)
+	}
+	b = append(b, s...)
+	if c&inlineXOR == inlineXOR {
+		// TODO: support and handle two-byte inline masks
+		b[len(b)-1] ^= byte(index)
+	} else {
+		for p := len(b) - int(xorData[index]); p < len(b); p++ {
+			index++
+			b[p] ^= xorData[index]
+		}
+	}
+	return b
+}
@@ -0,0 +1,30 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.16
+
+package idna
+
+// appendMapping appends the mapping for the respective rune. isMapped must be
+// true. A mapping is a categorization of a rune as defined in UTS #46.
+func (c info) appendMapping(b []byte, s string) []byte {
+	index := int(c >> indexShift)
+	if c&xorBit == 0 {
+		p := index
+		return append(b, mappings[mappingIndex[p]:mappingIndex[p+1]]...)
+	}
+	b = append(b, s...)
+	if c&inlineXOR == inlineXOR {
+		// TODO: support and handle two-byte inline masks
+		b[len(b)-1] ^= byte(index)
+	} else {
+		for p := len(b) - int(xorData[index]); p < len(b); p++ {
+			index++
+			b[p] ^= xorData[index]
+		}
+	}
+	return b
+}
@@ -0,0 +1,119 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package idna
+
+// This file contains definitions for interpreting the trie value of the idna
+// trie generated by "go run gen*.go". It is shared by both the generator
+// program and the resultant package. Sharing is achieved by the generator
+// copying gen_trieval.go to trieval.go and changing what's above this comment.
+
+// info holds information from the IDNA mapping table for a single rune. It is
+// the value returned by a trie lookup. In most cases, all information fits in
+// a 16-bit value. For mappings, this value may contain an index into a slice
+// with the mapped string. Such mappings can consist of the actual mapped value
+// or an XOR pattern to be applied to the bytes of the UTF8 encoding of the
+// input rune. This technique is used by the cases packages and reduces the
+// table size significantly.
+//
+// The per-rune values have the following format:
+//
+//	if mapped {
+//	  if inlinedXOR {
+//	    15..13 inline XOR marker
+//	    12..11 unused
+//	    10..3  inline XOR mask
+//	  } else {
+//	    15..3  index into xor or mapping table
+//	  }
+//	} else {
+//	    15..14 unused
+//	    13     mayNeedNorm
+//	    12..11 attributes
+//	    10..8  joining type
+//	     7..3  category type
+//	}
+//	   2  use xor pattern
+//	1..0  mapped category
+//
+// See the definitions below for a more detailed description of the various
+// bits.
+type info uint16
+
+const (
+	catSmallMask = 0x3
+	catBigMask   = 0xF8
+	indexShift   = 3
+	xorBit       = 0x4    // interpret the index as an xor pattern
+	inlineXOR    = 0xE000 // These bits are set if the XOR pattern is inlined.
+
+	joinShift = 8
+	joinMask  = 0x07
+
+	// Attributes
+	attributesMask = 0x1800
+	viramaModifier = 0x1800
+	modifier       = 0x1000
+	rtl            = 0x0800
+
+	mayNeedNorm = 0x2000
+)
+
+// A category corresponds to a category defined in the IDNA mapping table.
+type category uint16
+
+const (
+	unknown              category = 0 // not currently defined in unicode.
+	mapped               category = 1
+	disallowedSTD3Mapped category = 2
+	deviation            category = 3
+)
+
+const (
+	valid               category = 0x08
+	validNV8            category = 0x18
+	validXV8            category = 0x28
+	disallowed          category = 0x40
+	disallowedSTD3Valid category = 0x80
+	ignored             category = 0xC0
+)
+
+// join types and additional rune information
+const (
+	joiningL = (iota + 1)
+	joiningD
+	joiningT
+	joiningR
+
+	//the following types are derived during processing
+	joinZWJ
+	joinZWNJ
+	joinVirama
+	numJoinTypes
+)
+
+func (c info) isMapped() bool {
+	return c&0x3 != 0
+}
+
+func (c info) category() category {
+	small := c & catSmallMask
+	if small != 0 {
+		return category(small)
+	}
+	return category(c & catBigMask)
+}
+
+func (c info) joinType() info {
+	if c.isMapped() {
+		return 0
+	}
+	return (c >> joinShift) & joinMask
+}
+
+func (c info) isModifier() bool {
+	return c&(modifier|catSmallMask) == modifier
+}
+
+func (c info) isViramaModifier() bool {
+	return c&(attributesMask|catSmallMask) == viramaModifier
+}
@@ -0,0 +1,223 @@
+// go generate gen.go
+// Code generated by the command above; DO NOT EDIT.
+
+// Package iana provides protocol number resources managed by the Internet Assigned Numbers Authority (IANA).
+package iana // import "golang.org/x/net/internal/iana"
+
+// Differentiated Services Field Codepoints (DSCP), Updated: 2018-05-04
+const (
+	DiffServCS0           = 0x00 // CS0
+	DiffServCS1           = 0x20 // CS1
+	DiffServCS2           = 0x40 // CS2
+	DiffServCS3           = 0x60 // CS3
+	DiffServCS4           = 0x80 // CS4
+	DiffServCS5           = 0xa0 // CS5
+	DiffServCS6           = 0xc0 // CS6
+	DiffServCS7           = 0xe0 // CS7
+	DiffServAF11          = 0x28 // AF11
+	DiffServAF12          = 0x30 // AF12
+	DiffServAF13          = 0x38 // AF13
+	DiffServAF21          = 0x48 // AF21
+	DiffServAF22          = 0x50 // AF22
+	DiffServAF23          = 0x58 // AF23
+	DiffServAF31          = 0x68 // AF31
+	DiffServAF32          = 0x70 // AF32
+	DiffServAF33          = 0x78 // AF33
+	DiffServAF41          = 0x88 // AF41
+	DiffServAF42          = 0x90 // AF42
+	DiffServAF43          = 0x98 // AF43
+	DiffServEF            = 0xb8 // EF
+	DiffServVOICEADMIT    = 0xb0 // VOICE-ADMIT
+	NotECNTransport       = 0x00 // Not-ECT (Not ECN-Capable Transport)
+	ECNTransport1         = 0x01 // ECT(1) (ECN-Capable Transport(1))
+	ECNTransport0         = 0x02 // ECT(0) (ECN-Capable Transport(0))
+	CongestionExperienced = 0x03 // CE (Congestion Experienced)
+)
+
+// Protocol Numbers, Updated: 2017-10-13
+const (
+	ProtocolIP             = 0   // IPv4 encapsulation, pseudo protocol number
+	ProtocolHOPOPT         = 0   // IPv6 Hop-by-Hop Option
+	ProtocolICMP           = 1   // Internet Control Message
+	ProtocolIGMP           = 2   // Internet Group Management
+	ProtocolGGP            = 3   // Gateway-to-Gateway
+	ProtocolIPv4           = 4   // IPv4 encapsulation
+	ProtocolST             = 5   // Stream
+	ProtocolTCP            = 6   // Transmission Control
+	ProtocolCBT            = 7   // CBT
+	ProtocolEGP            = 8   // Exterior Gateway Protocol
+	ProtocolIGP            = 9   // any private interior gateway (used by Cisco for their IGRP)
+	ProtocolBBNRCCMON      = 10  // BBN RCC Monitoring
+	ProtocolNVPII          = 11  // Network Voice Protocol
+	ProtocolPUP            = 12  // PUP
+	ProtocolEMCON          = 14  // EMCON
+	ProtocolXNET           = 15  // Cross Net Debugger
+	ProtocolCHAOS          = 16  // Chaos
+	ProtocolUDP            = 17  // User Datagram
+	ProtocolMUX            = 18  // Multiplexing
+	ProtocolDCNMEAS        = 19  // DCN Measurement Subsystems
+	ProtocolHMP            = 20  // Host Monitoring
+	ProtocolPRM            = 21  // Packet Radio Measurement
+	ProtocolXNSIDP         = 22  // XEROX NS IDP
+	ProtocolTRUNK1         = 23  // Trunk-1
+	ProtocolTRUNK2         = 24  // Trunk-2
+	ProtocolLEAF1          = 25  // Leaf-1
+	ProtocolLEAF2          = 26  // Leaf-2
+	ProtocolRDP            = 27  // Reliable Data Protocol
+	ProtocolIRTP           = 28  // Internet Reliable Transaction
+	ProtocolISOTP4         = 29  // ISO Transport Protocol Class 4
+	ProtocolNETBLT         = 30  // Bulk Data Transfer Protocol
+	ProtocolMFENSP         = 31  // MFE Network Services Protocol
+	ProtocolMERITINP       = 32  // MERIT Internodal Protocol
+	ProtocolDCCP           = 33  // Datagram Congestion Control Protocol
+	Protocol3PC            = 34  // Third Party Connect Protocol
+	ProtocolIDPR           = 35  // Inter-Domain Policy Routing Protocol
+	ProtocolXTP            = 36  // XTP
+	ProtocolDDP            = 37  // Datagram Delivery Protocol
+	ProtocolIDPRCMTP       = 38  // IDPR Control Message Transport Proto
+	ProtocolTPPP           = 39  // TP++ Transport Protocol
+	ProtocolIL             = 40  // IL Transport Protocol
+	ProtocolIPv6           = 41  // IPv6 encapsulation
+	ProtocolSDRP           = 42  // Source Demand Routing Protocol
+	ProtocolIPv6Route      = 43  // Routing Header for IPv6
+	ProtocolIPv6Frag       = 44  // Fragment Header for IPv6
+	ProtocolIDRP           = 45  // Inter-Domain Routing Protocol
+	ProtocolRSVP           = 46  // Reservation Protocol
+	ProtocolGRE            = 47  // Generic Routing Encapsulation
+	ProtocolDSR            = 48  // Dynamic Source Routing Protocol
+	ProtocolBNA            = 49  // BNA
+	ProtocolESP            = 50  // Encap Security Payload
+	ProtocolAH             = 51  // Authentication Header
+	ProtocolINLSP          = 52  // Integrated Net Layer Security  TUBA
+	ProtocolNARP           = 54  // NBMA Address Resolution Protocol
+	ProtocolMOBILE         = 55  // IP Mobility
+	ProtocolTLSP           = 56  // Transport Layer Security Protocol using Kryptonet key management
+	ProtocolSKIP           = 57  // SKIP
+	ProtocolIPv6ICMP       = 58  // ICMP for IPv6
+	ProtocolIPv6NoNxt      = 59  // No Next Header for IPv6
+	ProtocolIPv6Opts       = 60  // Destination Options for IPv6
+	ProtocolCFTP           = 62  // CFTP
+	ProtocolSATEXPAK       = 64  // SATNET and Backroom EXPAK
+	ProtocolKRYPTOLAN      = 65  // Kryptolan
+	ProtocolRVD            = 66  // MIT Remote Virtual Disk Protocol
+	ProtocolIPPC           = 67  // Internet Pluribus Packet Core
+	ProtocolSATMON         = 69  // SATNET Monitoring
+	ProtocolVISA           = 70  // VISA Protocol
+	ProtocolIPCV           = 71  // Internet Packet Core Utility
+	ProtocolCPNX           = 72  // Computer Protocol Network Executive
+	ProtocolCPHB           = 73  // Computer Protocol Heart Beat
+	ProtocolWSN            = 74  // Wang Span Network
+	ProtocolPVP            = 75  // Packet Video Protocol
+	ProtocolBRSATMON       = 76  // Backroom SATNET Monitoring
+	ProtocolSUNND          = 77  // SUN ND PROTOCOL-Temporary
+	ProtocolWBMON          = 78  // WIDEBAND Monitoring
+	ProtocolWBEXPAK        = 79  // WIDEBAND EXPAK
+	ProtocolISOIP          = 80  // ISO Internet Protocol
+	ProtocolVMTP           = 81  // VMTP
+	ProtocolSECUREVMTP     = 82  // SECURE-VMTP
+	ProtocolVINES          = 83  // VINES
+	ProtocolTTP            = 84  // Transaction Transport Protocol
+	ProtocolIPTM           = 84  // Internet Protocol Traffic Manager
+	ProtocolNSFNETIGP      = 85  // NSFNET-IGP
+	ProtocolDGP            = 86  // Dissimilar Gateway Protocol
+	ProtocolTCF            = 87  // TCF
+	ProtocolEIGRP          = 88  // EIGRP
+	ProtocolOSPFIGP        = 89  // OSPFIGP
+	ProtocolSpriteRPC      = 90  // Sprite RPC Protocol
+	ProtocolLARP           = 91  // Locus Address Resolution Protocol
+	ProtocolMTP            = 92  // Multicast Transport Protocol
+	ProtocolAX25           = 93  // AX.25 Frames
+	ProtocolIPIP           = 94  // IP-within-IP Encapsulation Protocol
+	ProtocolSCCSP          = 96  // Semaphore Communications Sec. Pro.
+	ProtocolETHERIP        = 97  // Ethernet-within-IP Encapsulation
+	ProtocolENCAP          = 98  // Encapsulation Header
+	ProtocolGMTP           = 100 // GMTP
+	ProtocolIFMP           = 101 // Ipsilon Flow Management Protocol
+	ProtocolPNNI           = 102 // PNNI over IP
+	ProtocolPIM            = 103 // Protocol Independent Multicast
+	ProtocolARIS           = 104 // ARIS
+	ProtocolSCPS           = 105 // SCPS
+	ProtocolQNX            = 106 // QNX
+	ProtocolAN             = 107 // Active Networks
+	ProtocolIPComp         = 108 // IP Payload Compression Protocol
+	ProtocolSNP            = 109 // Sitara Networks Protocol
+	ProtocolCompaqPeer     = 110 // Compaq Peer Protocol
+	ProtocolIPXinIP        = 111 // IPX in IP
+	ProtocolVRRP           = 112 // Virtual Router Redundancy Protocol
+	ProtocolPGM            = 113 // PGM Reliable Transport Protocol
+	ProtocolL2TP           = 115 // Layer Two Tunneling Protocol
+	ProtocolDDX            = 116 // D-II Data Exchange (DDX)
+	ProtocolIATP           = 117 // Interactive Agent Transfer Protocol
+	ProtocolSTP            = 118 // Schedule Transfer Protocol
+	ProtocolSRP            = 119 // SpectraLink Radio Protocol
+	ProtocolUTI            = 120 // UTI
+	ProtocolSMP            = 121 // Simple Message Protocol
+	ProtocolPTP            = 123 // Performance Transparency Protocol
+	ProtocolISIS           = 124 // ISIS over IPv4
+	ProtocolFIRE           = 125 // FIRE
+	ProtocolCRTP           = 126 // Combat Radio Transport Protocol
+	ProtocolCRUDP          = 127 // Combat Radio User Datagram
+	ProtocolSSCOPMCE       = 128 // SSCOPMCE
+	ProtocolIPLT           = 129 // IPLT
+	ProtocolSPS            = 130 // Secure Packet Shield
+	ProtocolPIPE           = 131 // Private IP Encapsulation within IP
+	ProtocolSCTP           = 132 // Stream Control Transmission Protocol
+	ProtocolFC             = 133 // Fibre Channel
+	ProtocolRSVPE2EIGNORE  = 134 // RSVP-E2E-IGNORE
+	ProtocolMobilityHeader = 135 // Mobility Header
+	ProtocolUDPLite        = 136 // UDPLite
+	ProtocolMPLSinIP       = 137 // MPLS-in-IP
+	ProtocolMANET          = 138 // MANET Protocols
+	ProtocolHIP            = 139 // Host Identity Protocol
+	ProtocolShim6          = 140 // Shim6 Protocol
+	ProtocolWESP           = 141 // Wrapped Encapsulating Security Payload
+	ProtocolROHC           = 142 // Robust Header Compression
+	ProtocolReserved       = 255 // Reserved
+)
+
+// Address Family Numbers, Updated: 2018-04-02
+const (
+	AddrFamilyIPv4                          = 1     // IP (IP version 4)
+	AddrFamilyIPv6                          = 2     // IP6 (IP version 6)
+	AddrFamilyNSAP                          = 3     // NSAP
+	AddrFamilyHDLC                          = 4     // HDLC (8-bit multidrop)
+	AddrFamilyBBN1822                       = 5     // BBN 1822
+	AddrFamily802                           = 6     // 802 (includes all 802 media plus Ethernet "canonical format")
+	AddrFamilyE163                          = 7     // E.163
+	AddrFamilyE164                          = 8     // E.164 (SMDS, Frame Relay, ATM)
+	AddrFamilyF69                           = 9     // F.69 (Telex)
+	AddrFamilyX121                          = 10    // X.121 (X.25, Frame Relay)
+	AddrFamilyIPX                           = 11    // IPX
+	AddrFamilyAppletalk                     = 12    // Appletalk
+	AddrFamilyDecnetIV                      = 13    // Decnet IV
+	AddrFamilyBanyanVines                   = 14    // Banyan Vines
+	AddrFamilyE164withSubaddress            = 15    // E.164 with NSAP format subaddress
+	AddrFamilyDNS                           = 16    // DNS (Domain Name System)
+	AddrFamilyDistinguishedName             = 17    // Distinguished Name
+	AddrFamilyASNumber                      = 18    // AS Number
+	AddrFamilyXTPoverIPv4                   = 19    // XTP over IP version 4
+	AddrFamilyXTPoverIPv6                   = 20    // XTP over IP version 6
+	AddrFamilyXTPnativemodeXTP              = 21    // XTP native mode XTP
+	AddrFamilyFibreChannelWorldWidePortName = 22    // Fibre Channel World-Wide Port Name
+	AddrFamilyFibreChannelWorldWideNodeName = 23    // Fibre Channel World-Wide Node Name
+	AddrFamilyGWID                          = 24    // GWID
+	AddrFamilyL2VPN                         = 25    // AFI for L2VPN information
+	AddrFamilyMPLSTPSectionEndpointID       = 26    // MPLS-TP Section Endpoint Identifier
+	AddrFamilyMPLSTPLSPEndpointID           = 27    // MPLS-TP LSP Endpoint Identifier
+	AddrFamilyMPLSTPPseudowireEndpointID    = 28    // MPLS-TP Pseudowire Endpoint Identifier
+	AddrFamilyMTIPv4                        = 29    // MT IP: Multi-Topology IP version 4
+	AddrFamilyMTIPv6                        = 30    // MT IPv6: Multi-Topology IP version 6
+	AddrFamilyEIGRPCommonServiceFamily      = 16384 // EIGRP Common Service Family
+	AddrFamilyEIGRPIPv4ServiceFamily        = 16385 // EIGRP IPv4 Service Family
+	AddrFamilyEIGRPIPv6ServiceFamily        = 16386 // EIGRP IPv6 Service Family
+	AddrFamilyLISPCanonicalAddressFormat    = 16387 // LISP Canonical Address Format (LCAF)
+	AddrFamilyBGPLS                         = 16388 // BGP-LS
+	AddrFamily48bitMAC                      = 16389 // 48-bit MAC
+	AddrFamily64bitMAC                      = 16390 // 64-bit MAC
+	AddrFamilyOUI                           = 16391 // OUI
+	AddrFamilyMACFinal24bits                = 16392 // MAC/24
+	AddrFamilyMACFinal40bits                = 16393 // MAC/40
+	AddrFamilyIPv6Initial64bits             = 16394 // IPv6/64
+	AddrFamilyRBridgePortID                 = 16395 // RBridge Port ID
+	AddrFamilyTRILLNickname                 = 16396 // TRILL Nickname
+)
@@ -0,0 +1,11 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+
+package socket
+
+func (h *cmsghdr) len() int { return int(h.Len) }
+func (h *cmsghdr) lvl() int { return int(h.Level) }
+func (h *cmsghdr) typ() int { return int(h.Type) }
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || netbsd || openbsd
+
+package socket
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = uint32(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm || mips || mipsle || 386 || ppc) && linux
+
+package socket
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = uint32(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm64 || amd64 || loong64 || ppc64 || ppc64le || mips64 || mips64le || riscv64 || s390x) && linux
+
+package socket
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = uint64(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build amd64 && solaris
+
+package socket
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = uint32(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}
@@ -0,0 +1,27 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !zos
+
+package socket
+
+func controlHeaderLen() int {
+	return 0
+}
+
+func controlMessageLen(dataLen int) int {
+	return 0
+}
+
+func controlMessageSpace(dataLen int) int {
+	return 0
+}
+
+type cmsghdr struct{}
+
+func (h *cmsghdr) len() int { return 0 }
+func (h *cmsghdr) lvl() int { return 0 }
+func (h *cmsghdr) typ() int { return 0 }
+
+func (h *cmsghdr) set(l, lvl, typ int) {}
@@ -0,0 +1,21 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+
+package socket
+
+import "golang.org/x/sys/unix"
+
+func controlHeaderLen() int {
+	return unix.CmsgLen(0)
+}
+
+func controlMessageLen(dataLen int) int {
+	return unix.CmsgLen(dataLen)
+}
+
+func controlMessageSpace(dataLen int) int {
+	return unix.CmsgSpace(dataLen)
+}
@@ -0,0 +1,11 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+func (h *cmsghdr) set(l, lvl, typ int) {
+	h.Len = int32(l)
+	h.Level = int32(lvl)
+	h.Type = int32(typ)
+}
@@ -0,0 +1,25 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package socket
+
+import (
+	"syscall"
+)
+
+// ioComplete checks the flags and result of a syscall, to be used as return
+// value in a syscall.RawConn.Read or Write callback.
+func ioComplete(flags int, operr error) bool {
+	if flags&syscall.MSG_DONTWAIT != 0 {
+		// Caller explicitly said don't wait, so always return immediately.
+		return true
+	}
+	if operr == syscall.EAGAIN || operr == syscall.EWOULDBLOCK {
+		// No data available, block for I/O and try again.
+		return false
+	}
+	return true
+}
@@ -0,0 +1,21 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || windows || zos
+
+package socket
+
+import (
+	"syscall"
+)
+
+// ioComplete checks the flags and result of a syscall, to be used as return
+// value in a syscall.RawConn.Read or Write callback.
+func ioComplete(flags int, operr error) bool {
+	if operr == syscall.EAGAIN || operr == syscall.EWOULDBLOCK {
+		// No data available, block for I/O and try again.
+		return false
+	}
+	return true
+}
@@ -0,0 +1,7 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build darwin && go1.12
+
+// This exists solely so we can linkname in symbols from syscall.
@@ -0,0 +1,31 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+
+package socket
+
+import "syscall"
+
+var (
+	errEAGAIN error = syscall.EAGAIN
+	errEINVAL error = syscall.EINVAL
+	errENOENT error = syscall.ENOENT
+)
+
+// errnoErr returns common boxed Errno values, to prevent allocations
+// at runtime.
+func errnoErr(errno syscall.Errno) error {
+	switch errno {
+	case 0:
+		return nil
+	case syscall.EAGAIN:
+		return errEAGAIN
+	case syscall.EINVAL:
+		return errEINVAL
+	case syscall.ENOENT:
+		return errENOENT
+	}
+	return errno
+}
@@ -0,0 +1,26 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import "syscall"
+
+var (
+	errERROR_IO_PENDING error = syscall.ERROR_IO_PENDING
+	errEINVAL           error = syscall.EINVAL
+)
+
+// errnoErr returns common boxed Errno values, to prevent allocations
+// at runtime.
+func errnoErr(errno syscall.Errno) error {
+	switch errno {
+	case 0:
+		return nil
+	case syscall.ERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	case syscall.EINVAL:
+		return errEINVAL
+	}
+	return errno
+}
@@ -0,0 +1,18 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm || mips || mipsle || 386 || ppc) && (darwin || dragonfly || freebsd || linux || netbsd || openbsd)
+
+package socket
+
+import "unsafe"
+
+func (v *iovec) set(b []byte) {
+	l := len(b)
+	if l == 0 {
+		return
+	}
+	v.Base = (*byte)(unsafe.Pointer(&b[0]))
+	v.Len = uint32(l)
+}
@@ -0,0 +1,18 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm64 || amd64 || loong64 || ppc64 || ppc64le || mips64 || mips64le || riscv64 || s390x) && (aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || zos)
+
+package socket
+
+import "unsafe"
+
+func (v *iovec) set(b []byte) {
+	l := len(b)
+	if l == 0 {
+		return
+	}
+	v.Base = (*byte)(unsafe.Pointer(&b[0]))
+	v.Len = uint64(l)
+}
@@ -0,0 +1,18 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build amd64 && solaris
+
+package socket
+
+import "unsafe"
+
+func (v *iovec) set(b []byte) {
+	l := len(b)
+	if l == 0 {
+		return
+	}
+	v.Base = (*int8)(unsafe.Pointer(&b[0]))
+	v.Len = uint64(l)
+}
@@ -0,0 +1,11 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !zos
+
+package socket
+
+type iovec struct{}
+
+func (v *iovec) set(b []byte) {}
@@ -0,0 +1,21 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !linux && !netbsd
+
+package socket
+
+import "net"
+
+type mmsghdr struct{}
+
+type mmsghdrs []mmsghdr
+
+func (hs mmsghdrs) pack(ms []Message, parseFn func([]byte, string) (net.Addr, error), marshalFn func(net.Addr) []byte) error {
+	return nil
+}
+
+func (hs mmsghdrs) unpack(ms []Message, parseFn func([]byte, string) (net.Addr, error), hint string) error {
+	return nil
+}
@@ -0,0 +1,195 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || linux || netbsd
+
+package socket
+
+import (
+	"net"
+	"os"
+	"sync"
+	"syscall"
+)
+
+type mmsghdrs []mmsghdr
+
+func (hs mmsghdrs) unpack(ms []Message, parseFn func([]byte, string) (net.Addr, error), hint string) error {
+	for i := range hs {
+		ms[i].N = int(hs[i].Len)
+		ms[i].NN = hs[i].Hdr.controllen()
+		ms[i].Flags = hs[i].Hdr.flags()
+		if parseFn != nil {
+			var err error
+			ms[i].Addr, err = parseFn(hs[i].Hdr.name(), hint)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// mmsghdrsPacker packs Message-slices into mmsghdrs (re-)using pre-allocated buffers.
+type mmsghdrsPacker struct {
+	// hs are the pre-allocated mmsghdrs.
+	hs mmsghdrs
+	// sockaddrs is the pre-allocated buffer for the Hdr.Name buffers.
+	// We use one large buffer for all messages and slice it up.
+	sockaddrs []byte
+	// vs are the pre-allocated iovecs.
+	// We allocate one large buffer for all messages and slice it up. This allows to reuse the buffer
+	// if the number of buffers per message is distributed differently between calls.
+	vs []iovec
+}
+
+func (p *mmsghdrsPacker) prepare(ms []Message) {
+	n := len(ms)
+	if n <= cap(p.hs) {
+		p.hs = p.hs[:n]
+	} else {
+		p.hs = make(mmsghdrs, n)
+	}
+	if n*sizeofSockaddrInet6 <= cap(p.sockaddrs) {
+		p.sockaddrs = p.sockaddrs[:n*sizeofSockaddrInet6]
+	} else {
+		p.sockaddrs = make([]byte, n*sizeofSockaddrInet6)
+	}
+
+	nb := 0
+	for _, m := range ms {
+		nb += len(m.Buffers)
+	}
+	if nb <= cap(p.vs) {
+		p.vs = p.vs[:nb]
+	} else {
+		p.vs = make([]iovec, nb)
+	}
+}
+
+func (p *mmsghdrsPacker) pack(ms []Message, parseFn func([]byte, string) (net.Addr, error), marshalFn func(net.Addr, []byte) int) mmsghdrs {
+	p.prepare(ms)
+	hs := p.hs
+	vsRest := p.vs
+	saRest := p.sockaddrs
+	for i := range hs {
+		nvs := len(ms[i].Buffers)
+		vs := vsRest[:nvs]
+		vsRest = vsRest[nvs:]
+
+		var sa []byte
+		if parseFn != nil {
+			sa = saRest[:sizeofSockaddrInet6]
+			saRest = saRest[sizeofSockaddrInet6:]
+		} else if marshalFn != nil {
+			n := marshalFn(ms[i].Addr, saRest)
+			if n > 0 {
+				sa = saRest[:n]
+				saRest = saRest[n:]
+			}
+		}
+		hs[i].Hdr.pack(vs, ms[i].Buffers, ms[i].OOB, sa)
+	}
+	return hs
+}
+
+// syscaller is a helper to invoke recvmmsg and sendmmsg via the RawConn.Read/Write interface.
+// It is reusable, to amortize the overhead of allocating a closure for the function passed to
+// RawConn.Read/Write.
+type syscaller struct {
+	n     int
+	operr error
+	hs    mmsghdrs
+	flags int
+
+	boundRecvmmsgF func(uintptr) bool
+	boundSendmmsgF func(uintptr) bool
+}
+
+func (r *syscaller) init() {
+	r.boundRecvmmsgF = r.recvmmsgF
+	r.boundSendmmsgF = r.sendmmsgF
+}
+
+func (r *syscaller) recvmmsg(c syscall.RawConn, hs mmsghdrs, flags int) (int, error) {
+	r.n = 0
+	r.operr = nil
+	r.hs = hs
+	r.flags = flags
+	if err := c.Read(r.boundRecvmmsgF); err != nil {
+		return r.n, err
+	}
+	if r.operr != nil {
+		return r.n, os.NewSyscallError("recvmmsg", r.operr)
+	}
+	return r.n, nil
+}
+
+func (r *syscaller) recvmmsgF(s uintptr) bool {
+	r.n, r.operr = recvmmsg(s, r.hs, r.flags)
+	return ioComplete(r.flags, r.operr)
+}
+
+func (r *syscaller) sendmmsg(c syscall.RawConn, hs mmsghdrs, flags int) (int, error) {
+	r.n = 0
+	r.operr = nil
+	r.hs = hs
+	r.flags = flags
+	if err := c.Write(r.boundSendmmsgF); err != nil {
+		return r.n, err
+	}
+	if r.operr != nil {
+		return r.n, os.NewSyscallError("sendmmsg", r.operr)
+	}
+	return r.n, nil
+}
+
+func (r *syscaller) sendmmsgF(s uintptr) bool {
+	r.n, r.operr = sendmmsg(s, r.hs, r.flags)
+	return ioComplete(r.flags, r.operr)
+}
+
+// mmsgTmps holds reusable temporary helpers for recvmmsg and sendmmsg.
+type mmsgTmps struct {
+	packer    mmsghdrsPacker
+	syscaller syscaller
+}
+
+var defaultMmsgTmpsPool = mmsgTmpsPool{
+	p: sync.Pool{
+		New: func() interface{} {
+			tmps := new(mmsgTmps)
+			tmps.syscaller.init()
+			return tmps
+		},
+	},
+}
+
+type mmsgTmpsPool struct {
+	p sync.Pool
+}
+
+func (p *mmsgTmpsPool) Get() *mmsgTmps {
+	m := p.p.Get().(*mmsgTmps)
+	// Clear fields up to the len (not the cap) of the slice,
+	// assuming that the previous caller only used that many elements.
+	for i := range m.packer.sockaddrs {
+		m.packer.sockaddrs[i] = 0
+	}
+	m.packer.sockaddrs = m.packer.sockaddrs[:0]
+	for i := range m.packer.vs {
+		m.packer.vs[i] = iovec{}
+	}
+	m.packer.vs = m.packer.vs[:0]
+	for i := range m.packer.hs {
+		m.packer.hs[i].Len = 0
+		m.packer.hs[i].Hdr = msghdr{}
+	}
+	m.packer.hs = m.packer.hs[:0]
+	return m
+}
+
+func (p *mmsgTmpsPool) Put(tmps *mmsgTmps) {
+	p.p.Put(tmps)
+}
@@ -0,0 +1,39 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || netbsd || openbsd
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
+	for i := range vs {
+		vs[i].set(bs[i])
+	}
+	h.setIov(vs)
+	if len(oob) > 0 {
+		h.Control = (*byte)(unsafe.Pointer(&oob[0]))
+		h.Controllen = uint32(len(oob))
+	}
+	if sa != nil {
+		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
+		h.Namelen = uint32(len(sa))
+	}
+}
+
+func (h *msghdr) name() []byte {
+	if h.Name != nil && h.Namelen > 0 {
+		return (*[sizeofSockaddrInet6]byte)(unsafe.Pointer(h.Name))[:h.Namelen]
+	}
+	return nil
+}
+
+func (h *msghdr) controllen() int {
+	return int(h.Controllen)
+}
+
+func (h *msghdr) flags() int {
+	return int(h.Flags)
+}
@@ -0,0 +1,16 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || netbsd
+
+package socket
+
+func (h *msghdr) setIov(vs []iovec) {
+	l := len(vs)
+	if l == 0 {
+		return
+	}
+	h.Iov = &vs[0]
+	h.Iovlen = int32(l)
+}
@@ -0,0 +1,36 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
+	for i := range vs {
+		vs[i].set(bs[i])
+	}
+	h.setIov(vs)
+	if len(oob) > 0 {
+		h.setControl(oob)
+	}
+	if sa != nil {
+		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
+		h.Namelen = uint32(len(sa))
+	}
+}
+
+func (h *msghdr) name() []byte {
+	if h.Name != nil && h.Namelen > 0 {
+		return (*[sizeofSockaddrInet6]byte)(unsafe.Pointer(h.Name))[:h.Namelen]
+	}
+	return nil
+}
+
+func (h *msghdr) controllen() int {
+	return int(h.Controllen)
+}
+
+func (h *msghdr) flags() int {
+	return int(h.Flags)
+}
@@ -0,0 +1,23 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm || mips || mipsle || 386 || ppc) && linux
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) setIov(vs []iovec) {
+	l := len(vs)
+	if l == 0 {
+		return
+	}
+	h.Iov = &vs[0]
+	h.Iovlen = uint32(l)
+}
+
+func (h *msghdr) setControl(b []byte) {
+	h.Control = (*byte)(unsafe.Pointer(&b[0]))
+	h.Controllen = uint32(len(b))
+}
@@ -0,0 +1,23 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (arm64 || amd64 || loong64 || ppc64 || ppc64le || mips64 || mips64le || riscv64 || s390x) && linux
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) setIov(vs []iovec) {
+	l := len(vs)
+	if l == 0 {
+		return
+	}
+	h.Iov = &vs[0]
+	h.Iovlen = uint64(l)
+}
+
+func (h *msghdr) setControl(b []byte) {
+	h.Control = (*byte)(unsafe.Pointer(&b[0]))
+	h.Controllen = uint64(len(b))
+}
@@ -0,0 +1,14 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+func (h *msghdr) setIov(vs []iovec) {
+	l := len(vs)
+	if l == 0 {
+		return
+	}
+	h.Iov = &vs[0]
+	h.Iovlen = uint32(l)
+}
@@ -0,0 +1,35 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build amd64 && solaris
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
+	for i := range vs {
+		vs[i].set(bs[i])
+	}
+	if len(vs) > 0 {
+		h.Iov = &vs[0]
+		h.Iovlen = int32(len(vs))
+	}
+	if len(oob) > 0 {
+		h.Accrights = (*int8)(unsafe.Pointer(&oob[0]))
+		h.Accrightslen = int32(len(oob))
+	}
+	if sa != nil {
+		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
+		h.Namelen = uint32(len(sa))
+	}
+}
+
+func (h *msghdr) controllen() int {
+	return int(h.Accrightslen)
+}
+
+func (h *msghdr) flags() int {
+	return int(NativeEndian.Uint32(h.Pad_cgo_2[:]))
+}
@@ -0,0 +1,14 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !zos
+
+package socket
+
+type msghdr struct{}
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {}
+func (h *msghdr) name() []byte                                        { return nil }
+func (h *msghdr) controllen() int                                     { return 0 }
+func (h *msghdr) flags() int                                          { return 0 }
@@ -0,0 +1,35 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build s390x && zos
+
+package socket
+
+import "unsafe"
+
+func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
+	for i := range vs {
+		vs[i].set(bs[i])
+	}
+	if len(vs) > 0 {
+		h.Iov = &vs[0]
+		h.Iovlen = int32(len(vs))
+	}
+	if len(oob) > 0 {
+		h.Control = (*byte)(unsafe.Pointer(&oob[0]))
+		h.Controllen = uint32(len(oob))
+	}
+	if sa != nil {
+		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
+		h.Namelen = uint32(len(sa))
+	}
+}
+
+func (h *msghdr) controllen() int {
+	return int(h.Controllen)
+}
+
+func (h *msghdr) flags() int {
+	return int(h.Flags)
+}
@@ -0,0 +1,12 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !race
+
+package socket
+
+func (m *Message) raceRead() {
+}
+func (m *Message) raceWrite() {
+}
@@ -0,0 +1,37 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build race
+
+package socket
+
+import (
+	"runtime"
+	"unsafe"
+)
+
+// This package reads and writes the Message buffers using a
+// direct system call, which the race detector can't see.
+// These functions tell the race detector what is going on during the syscall.
+
+func (m *Message) raceRead() {
+	for _, b := range m.Buffers {
+		if len(b) > 0 {
+			runtime.RaceReadRange(unsafe.Pointer(&b[0]), len(b))
+		}
+	}
+	if b := m.OOB; len(b) > 0 {
+		runtime.RaceReadRange(unsafe.Pointer(&b[0]), len(b))
+	}
+}
+func (m *Message) raceWrite() {
+	for _, b := range m.Buffers {
+		if len(b) > 0 {
+			runtime.RaceWriteRange(unsafe.Pointer(&b[0]), len(b))
+		}
+	}
+	if b := m.OOB; len(b) > 0 {
+		runtime.RaceWriteRange(unsafe.Pointer(&b[0]), len(b))
+	}
+}
@@ -0,0 +1,91 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"errors"
+	"net"
+	"os"
+	"syscall"
+)
+
+// A Conn represents a raw connection.
+type Conn struct {
+	network string
+	c       syscall.RawConn
+}
+
+// tcpConn is an interface implemented by net.TCPConn.
+// It can be used for interface assertions to check if a net.Conn is a TCP connection.
+type tcpConn interface {
+	SyscallConn() (syscall.RawConn, error)
+	SetLinger(int) error
+}
+
+var _ tcpConn = (*net.TCPConn)(nil)
+
+// udpConn is an interface implemented by net.UDPConn.
+// It can be used for interface assertions to check if a net.Conn is a UDP connection.
+type udpConn interface {
+	SyscallConn() (syscall.RawConn, error)
+	ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *net.UDPAddr, err error)
+}
+
+var _ udpConn = (*net.UDPConn)(nil)
+
+// ipConn is an interface implemented by net.IPConn.
+// It can be used for interface assertions to check if a net.Conn is an IP connection.
+type ipConn interface {
+	SyscallConn() (syscall.RawConn, error)
+	ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *net.IPAddr, err error)
+}
+
+var _ ipConn = (*net.IPConn)(nil)
+
+// NewConn returns a new raw connection.
+func NewConn(c net.Conn) (*Conn, error) {
+	var err error
+	var cc Conn
+	switch c := c.(type) {
+	case tcpConn:
+		cc.network = "tcp"
+		cc.c, err = c.SyscallConn()
+	case udpConn:
+		cc.network = "udp"
+		cc.c, err = c.SyscallConn()
+	case ipConn:
+		cc.network = "ip"
+		cc.c, err = c.SyscallConn()
+	default:
+		return nil, errors.New("unknown connection type")
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &cc, nil
+}
+
+func (o *Option) get(c *Conn, b []byte) (int, error) {
+	var operr error
+	var n int
+	fn := func(s uintptr) {
+		n, operr = getsockopt(s, o.Level, o.Name, b)
+	}
+	if err := c.c.Control(fn); err != nil {
+		return 0, err
+	}
+	return n, os.NewSyscallError("getsockopt", operr)
+}
+
+func (o *Option) set(c *Conn, b []byte) error {
+	var operr error
+	fn := func(s uintptr) {
+		operr = setsockopt(s, o.Level, o.Name, b)
+	}
+	if err := c.c.Control(fn); err != nil {
+		return err
+	}
+	return os.NewSyscallError("setsockopt", operr)
+}
@@ -0,0 +1,53 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux
+
+package socket
+
+import (
+	"net"
+)
+
+func (c *Conn) recvMsgs(ms []Message, flags int) (int, error) {
+	for i := range ms {
+		ms[i].raceWrite()
+	}
+	tmps := defaultMmsgTmpsPool.Get()
+	defer defaultMmsgTmpsPool.Put(tmps)
+	var parseFn func([]byte, string) (net.Addr, error)
+	if c.network != "tcp" {
+		parseFn = parseInetAddr
+	}
+	hs := tmps.packer.pack(ms, parseFn, nil)
+	n, err := tmps.syscaller.recvmmsg(c.c, hs, flags)
+	if err != nil {
+		return n, err
+	}
+	if err := hs[:n].unpack(ms[:n], parseFn, c.network); err != nil {
+		return n, err
+	}
+	return n, nil
+}
+
+func (c *Conn) sendMsgs(ms []Message, flags int) (int, error) {
+	for i := range ms {
+		ms[i].raceRead()
+	}
+	tmps := defaultMmsgTmpsPool.Get()
+	defer defaultMmsgTmpsPool.Put(tmps)
+	var marshalFn func(net.Addr, []byte) int
+	if c.network != "tcp" {
+		marshalFn = marshalInetAddr
+	}
+	hs := tmps.packer.pack(ms, nil, marshalFn)
+	n, err := tmps.syscaller.sendmmsg(c.c, hs, flags)
+	if err != nil {
+		return n, err
+	}
+	if err := hs[:n].unpack(ms[:n], nil, ""); err != nil {
+		return n, err
+	}
+	return n, nil
+}
@@ -0,0 +1,59 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || windows || zos
+
+package socket
+
+import (
+	"net"
+	"os"
+)
+
+func (c *Conn) recvMsg(m *Message, flags int) error {
+	m.raceWrite()
+	var (
+		operr     error
+		n         int
+		oobn      int
+		recvflags int
+		from      net.Addr
+	)
+	fn := func(s uintptr) bool {
+		n, oobn, recvflags, from, operr = recvmsg(s, m.Buffers, m.OOB, flags, c.network)
+		return ioComplete(flags, operr)
+	}
+	if err := c.c.Read(fn); err != nil {
+		return err
+	}
+	if operr != nil {
+		return os.NewSyscallError("recvmsg", operr)
+	}
+	m.Addr = from
+	m.N = n
+	m.NN = oobn
+	m.Flags = recvflags
+	return nil
+}
+
+func (c *Conn) sendMsg(m *Message, flags int) error {
+	m.raceRead()
+	var (
+		operr error
+		n     int
+	)
+	fn := func(s uintptr) bool {
+		n, operr = sendmsg(s, m.Buffers, m.OOB, m.Addr, flags)
+		return ioComplete(flags, operr)
+	}
+	if err := c.c.Write(fn); err != nil {
+		return err
+	}
+	if operr != nil {
+		return os.NewSyscallError("sendmsg", operr)
+	}
+	m.N = n
+	m.NN = len(m.OOB)
+	return nil
+}
@@ -0,0 +1,15 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !linux
+
+package socket
+
+func (c *Conn) recvMsgs(ms []Message, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func (c *Conn) sendMsgs(ms []Message, flags int) (int, error) {
+	return 0, errNotImplemented
+}
@@ -0,0 +1,15 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !windows && !zos
+
+package socket
+
+func (c *Conn) recvMsg(m *Message, flags int) error {
+	return errNotImplemented
+}
+
+func (c *Conn) sendMsg(m *Message, flags int) error {
+	return errNotImplemented
+}
@@ -0,0 +1,280 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package socket provides a portable interface for socket system
+// calls.
+package socket // import "golang.org/x/net/internal/socket"
+
+import (
+	"errors"
+	"net"
+	"runtime"
+	"unsafe"
+)
+
+var errNotImplemented = errors.New("not implemented on " + runtime.GOOS + "/" + runtime.GOARCH)
+
+// An Option represents a sticky socket option.
+type Option struct {
+	Level int // level
+	Name  int // name; must be equal or greater than 1
+	Len   int // length of value in bytes; must be equal or greater than 1
+}
+
+// Get reads a value for the option from the kernel.
+// It returns the number of bytes written into b.
+func (o *Option) Get(c *Conn, b []byte) (int, error) {
+	if o.Name < 1 || o.Len < 1 {
+		return 0, errors.New("invalid option")
+	}
+	if len(b) < o.Len {
+		return 0, errors.New("short buffer")
+	}
+	return o.get(c, b)
+}
+
+// GetInt returns an integer value for the option.
+//
+// The Len field of Option must be either 1 or 4.
+func (o *Option) GetInt(c *Conn) (int, error) {
+	if o.Len != 1 && o.Len != 4 {
+		return 0, errors.New("invalid option")
+	}
+	var b []byte
+	var bb [4]byte
+	if o.Len == 1 {
+		b = bb[:1]
+	} else {
+		b = bb[:4]
+	}
+	n, err := o.get(c, b)
+	if err != nil {
+		return 0, err
+	}
+	if n != o.Len {
+		return 0, errors.New("invalid option length")
+	}
+	if o.Len == 1 {
+		return int(b[0]), nil
+	}
+	return int(NativeEndian.Uint32(b[:4])), nil
+}
+
+// Set writes the option and value to the kernel.
+func (o *Option) Set(c *Conn, b []byte) error {
+	if o.Name < 1 || o.Len < 1 {
+		return errors.New("invalid option")
+	}
+	if len(b) < o.Len {
+		return errors.New("short buffer")
+	}
+	return o.set(c, b)
+}
+
+// SetInt writes the option and value to the kernel.
+//
+// The Len field of Option must be either 1 or 4.
+func (o *Option) SetInt(c *Conn, v int) error {
+	if o.Len != 1 && o.Len != 4 {
+		return errors.New("invalid option")
+	}
+	var b []byte
+	if o.Len == 1 {
+		b = []byte{byte(v)}
+	} else {
+		var bb [4]byte
+		NativeEndian.PutUint32(bb[:o.Len], uint32(v))
+		b = bb[:4]
+	}
+	return o.set(c, b)
+}
+
+// ControlMessageSpace returns the whole length of control message.
+func ControlMessageSpace(dataLen int) int {
+	return controlMessageSpace(dataLen)
+}
+
+// A ControlMessage represents the head message in a stream of control
+// messages.
+//
+// A control message comprises of a header, data and a few padding
+// fields to conform to the interface to the kernel.
+//
+// See RFC 3542 for further information.
+type ControlMessage []byte
+
+// Data returns the data field of the control message at the head on
+// m.
+func (m ControlMessage) Data(dataLen int) []byte {
+	l := controlHeaderLen()
+	if len(m) < l || len(m) < l+dataLen {
+		return nil
+	}
+	return m[l : l+dataLen]
+}
+
+// Next returns the control message at the next on m.
+//
+// Next works only for standard control messages.
+func (m ControlMessage) Next(dataLen int) ControlMessage {
+	l := ControlMessageSpace(dataLen)
+	if len(m) < l {
+		return nil
+	}
+	return m[l:]
+}
+
+// MarshalHeader marshals the header fields of the control message at
+// the head on m.
+func (m ControlMessage) MarshalHeader(lvl, typ, dataLen int) error {
+	if len(m) < controlHeaderLen() {
+		return errors.New("short message")
+	}
+	h := (*cmsghdr)(unsafe.Pointer(&m[0]))
+	h.set(controlMessageLen(dataLen), lvl, typ)
+	return nil
+}
+
+// ParseHeader parses and returns the header fields of the control
+// message at the head on m.
+func (m ControlMessage) ParseHeader() (lvl, typ, dataLen int, err error) {
+	l := controlHeaderLen()
+	if len(m) < l {
+		return 0, 0, 0, errors.New("short message")
+	}
+	h := (*cmsghdr)(unsafe.Pointer(&m[0]))
+	return h.lvl(), h.typ(), int(uint64(h.len()) - uint64(l)), nil
+}
+
+// Marshal marshals the control message at the head on m, and returns
+// the next control message.
+func (m ControlMessage) Marshal(lvl, typ int, data []byte) (ControlMessage, error) {
+	l := len(data)
+	if len(m) < ControlMessageSpace(l) {
+		return nil, errors.New("short message")
+	}
+	h := (*cmsghdr)(unsafe.Pointer(&m[0]))
+	h.set(controlMessageLen(l), lvl, typ)
+	if l > 0 {
+		copy(m.Data(l), data)
+	}
+	return m.Next(l), nil
+}
+
+// Parse parses m as a single or multiple control messages.
+//
+// Parse works for both standard and compatible messages.
+func (m ControlMessage) Parse() ([]ControlMessage, error) {
+	var ms []ControlMessage
+	for len(m) >= controlHeaderLen() {
+		h := (*cmsghdr)(unsafe.Pointer(&m[0]))
+		l := h.len()
+		if l <= 0 {
+			return nil, errors.New("invalid header length")
+		}
+		if uint64(l) < uint64(controlHeaderLen()) {
+			return nil, errors.New("invalid message length")
+		}
+		if uint64(l) > uint64(len(m)) {
+			return nil, errors.New("short buffer")
+		}
+		// On message reception:
+		//
+		// |<- ControlMessageSpace --------------->|
+		// |<- controlMessageLen ---------->|      |
+		// |<- controlHeaderLen ->|         |      |
+		// +---------------+------+---------+------+
+		// |    Header     | PadH |  Data   | PadD |
+		// +---------------+------+---------+------+
+		//
+		// On compatible message reception:
+		//
+		// | ... |<- controlMessageLen ----------->|
+		// | ... |<- controlHeaderLen ->|          |
+		// +-----+---------------+------+----------+
+		// | ... |    Header     | PadH |   Data   |
+		// +-----+---------------+------+----------+
+		ms = append(ms, ControlMessage(m[:l]))
+		ll := l - controlHeaderLen()
+		if len(m) >= ControlMessageSpace(ll) {
+			m = m[ControlMessageSpace(ll):]
+		} else {
+			m = m[controlMessageLen(ll):]
+		}
+	}
+	return ms, nil
+}
+
+// NewControlMessage returns a new stream of control messages.
+func NewControlMessage(dataLen []int) ControlMessage {
+	var l int
+	for i := range dataLen {
+		l += ControlMessageSpace(dataLen[i])
+	}
+	return make([]byte, l)
+}
+
+// A Message represents an IO message.
+type Message struct {
+	// When writing, the Buffers field must contain at least one
+	// byte to write.
+	// When reading, the Buffers field will always contain a byte
+	// to read.
+	Buffers [][]byte
+
+	// OOB contains protocol-specific control or miscellaneous
+	// ancillary data known as out-of-band data.
+	OOB []byte
+
+	// Addr specifies a destination address when writing.
+	// It can be nil when the underlying protocol of the raw
+	// connection uses connection-oriented communication.
+	// After a successful read, it may contain the source address
+	// on the received packet.
+	Addr net.Addr
+
+	N     int // # of bytes read or written from/to Buffers
+	NN    int // # of bytes read or written from/to OOB
+	Flags int // protocol-specific information on the received message
+}
+
+// RecvMsg wraps recvmsg system call.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_PEEK.
+func (c *Conn) RecvMsg(m *Message, flags int) error {
+	return c.recvMsg(m, flags)
+}
+
+// SendMsg wraps sendmsg system call.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_DONTROUTE.
+func (c *Conn) SendMsg(m *Message, flags int) error {
+	return c.sendMsg(m, flags)
+}
+
+// RecvMsgs wraps recvmmsg system call.
+//
+// It returns the number of processed messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_PEEK.
+//
+// Only Linux supports this.
+func (c *Conn) RecvMsgs(ms []Message, flags int) (int, error) {
+	return c.recvMsgs(ms, flags)
+}
+
+// SendMsgs wraps sendmmsg system call.
+//
+// It returns the number of processed messages.
+//
+// The provided flags is a set of platform-dependent flags, such as
+// syscall.MSG_DONTROUTE.
+//
+// Only Linux supports this.
+func (c *Conn) SendMsgs(ms []Message, flags int) (int, error) {
+	return c.sendMsgs(ms, flags)
+}
@@ -0,0 +1,23 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"encoding/binary"
+	"unsafe"
+)
+
+// NativeEndian is the machine native endian implementation of ByteOrder.
+var NativeEndian binary.ByteOrder
+
+func init() {
+	i := uint32(1)
+	b := (*[4]byte)(unsafe.Pointer(&i))
+	if b[0] == 1 {
+		NativeEndian = binary.LittleEndian
+	} else {
+		NativeEndian = binary.BigEndian
+	}
+}
@@ -0,0 +1,15 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || openbsd || solaris
+
+package socket
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
@@ -0,0 +1,20 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+
+package socket
+
+import "golang.org/x/sys/unix"
+
+const (
+	sysAF_UNSPEC = unix.AF_UNSPEC
+	sysAF_INET   = unix.AF_INET
+	sysAF_INET6  = unix.AF_INET6
+
+	sysSOCK_RAW = unix.SOCK_RAW
+
+	sizeofSockaddrInet4 = unix.SizeofSockaddrInet4
+	sizeofSockaddrInet6 = unix.SizeofSockaddrInet6
+)
@@ -0,0 +1,22 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux && !s390x && !386
+
+package socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, _, errno := syscall.Syscall6(sysRECVMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, _, errno := syscall.Syscall6(sysSENDMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
@@ -0,0 +1,28 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	sysRECVMMSG = 0x13
+	sysSENDMMSG = 0x14
+)
+
+func socketcall(call, a0, a1, a2, a3, a4, a5 uintptr) (uintptr, syscall.Errno)
+func rawsocketcall(call, a0, a1, a2, a3, a4, a5 uintptr) (uintptr, syscall.Errno)
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, errno := socketcall(sysRECVMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, errno := socketcall(sysSENDMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
@@ -0,0 +1,11 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+TEXT	·socketcall(SB),NOSPLIT,$0-36
+	JMP	syscall·socketcall(SB)
+
+TEXT	·rawsocketcall(SB),NOSPLIT,$0-36
+	JMP	syscall·rawsocketcall(SB)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x12b
+	sysSENDMMSG = 0x133
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x16d
+	sysSENDMMSG = 0x176
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0xf3
+	sysSENDMMSG = 0x10d
+)
@@ -0,0 +1,12 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build loong64
+
+package socket
+
+const (
+	sysRECVMMSG = 0xf3
+	sysSENDMMSG = 0x10d
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x10ef
+	sysSENDMMSG = 0x10f7
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x14ae
+	sysSENDMMSG = 0x14b6
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x14ae
+	sysSENDMMSG = 0x14b6
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x10ef
+	sysSENDMMSG = 0x10f7
+)
@@ -0,0 +1,10 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x157
+	sysSENDMMSG = 0x15d
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x157
+	sysSENDMMSG = 0x15d
+)
@@ -0,0 +1,10 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+const (
+	sysRECVMMSG = 0x157
+	sysSENDMMSG = 0x15d
+)
@@ -0,0 +1,12 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build riscv64
+
+package socket
+
+const (
+	sysRECVMMSG = 0xf3
+	sysSENDMMSG = 0x10d
+)
@@ -0,0 +1,28 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	sysRECVMMSG = 0x13
+	sysSENDMMSG = 0x14
+)
+
+func socketcall(call, a0, a1, a2, a3, a4, a5 uintptr) (uintptr, syscall.Errno)
+func rawsocketcall(call, a0, a1, a2, a3, a4, a5 uintptr) (uintptr, syscall.Errno)
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, errno := socketcall(sysRECVMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, errno := socketcall(sysSENDMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
@@ -0,0 +1,11 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+TEXT	·socketcall(SB),NOSPLIT,$0-72
+	JMP	syscall·socketcall(SB)
+
+TEXT	·rawsocketcall(SB),NOSPLIT,$0-72
+	JMP	syscall·rawsocketcall(SB)
@@ -0,0 +1,25 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	sysRECVMMSG = 0x1db
+	sysSENDMMSG = 0x1dc
+)
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, _, errno := syscall.Syscall6(sysRECVMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	n, _, errno := syscall.Syscall6(sysSENDMMSG, s, uintptr(unsafe.Pointer(&hs[0])), uintptr(len(hs)), uintptr(flags), 0, 0)
+	return int(n), errnoErr(errno)
+}
@@ -0,0 +1,184 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || windows || zos
+
+package socket
+
+import (
+	"encoding/binary"
+	"errors"
+	"net"
+	"runtime"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// marshalInetAddr writes a in sockaddr format into the buffer b.
+// The buffer must be sufficiently large (sizeofSockaddrInet4/6).
+// Returns the number of bytes written.
+func marshalInetAddr(a net.Addr, b []byte) int {
+	switch a := a.(type) {
+	case *net.TCPAddr:
+		return marshalSockaddr(a.IP, a.Port, a.Zone, b)
+	case *net.UDPAddr:
+		return marshalSockaddr(a.IP, a.Port, a.Zone, b)
+	case *net.IPAddr:
+		return marshalSockaddr(a.IP, 0, a.Zone, b)
+	default:
+		return 0
+	}
+}
+
+func marshalSockaddr(ip net.IP, port int, zone string, b []byte) int {
+	if ip4 := ip.To4(); ip4 != nil {
+		switch runtime.GOOS {
+		case "android", "illumos", "linux", "solaris", "windows":
+			NativeEndian.PutUint16(b[:2], uint16(sysAF_INET))
+		default:
+			b[0] = sizeofSockaddrInet4
+			b[1] = sysAF_INET
+		}
+		binary.BigEndian.PutUint16(b[2:4], uint16(port))
+		copy(b[4:8], ip4)
+		return sizeofSockaddrInet4
+	}
+	if ip6 := ip.To16(); ip6 != nil && ip.To4() == nil {
+		switch runtime.GOOS {
+		case "android", "illumos", "linux", "solaris", "windows":
+			NativeEndian.PutUint16(b[:2], uint16(sysAF_INET6))
+		default:
+			b[0] = sizeofSockaddrInet6
+			b[1] = sysAF_INET6
+		}
+		binary.BigEndian.PutUint16(b[2:4], uint16(port))
+		copy(b[8:24], ip6)
+		if zone != "" {
+			NativeEndian.PutUint32(b[24:28], uint32(zoneCache.index(zone)))
+		}
+		return sizeofSockaddrInet6
+	}
+	return 0
+}
+
+func parseInetAddr(b []byte, network string) (net.Addr, error) {
+	if len(b) < 2 {
+		return nil, errors.New("invalid address")
+	}
+	var af int
+	switch runtime.GOOS {
+	case "android", "illumos", "linux", "solaris", "windows":
+		af = int(NativeEndian.Uint16(b[:2]))
+	default:
+		af = int(b[1])
+	}
+	var ip net.IP
+	var zone string
+	if af == sysAF_INET {
+		if len(b) < sizeofSockaddrInet4 {
+			return nil, errors.New("short address")
+		}
+		ip = make(net.IP, net.IPv4len)
+		copy(ip, b[4:8])
+	}
+	if af == sysAF_INET6 {
+		if len(b) < sizeofSockaddrInet6 {
+			return nil, errors.New("short address")
+		}
+		ip = make(net.IP, net.IPv6len)
+		copy(ip, b[8:24])
+		if id := int(NativeEndian.Uint32(b[24:28])); id > 0 {
+			zone = zoneCache.name(id)
+		}
+	}
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		return &net.TCPAddr{IP: ip, Port: int(binary.BigEndian.Uint16(b[2:4])), Zone: zone}, nil
+	case "udp", "udp4", "udp6":
+		return &net.UDPAddr{IP: ip, Port: int(binary.BigEndian.Uint16(b[2:4])), Zone: zone}, nil
+	default:
+		return &net.IPAddr{IP: ip, Zone: zone}, nil
+	}
+}
+
+// An ipv6ZoneCache represents a cache holding partial network
+// interface information. It is used for reducing the cost of IPv6
+// addressing scope zone resolution.
+//
+// Multiple names sharing the index are managed by first-come
+// first-served basis for consistency.
+type ipv6ZoneCache struct {
+	sync.RWMutex                // guard the following
+	lastFetched  time.Time      // last time routing information was fetched
+	toIndex      map[string]int // interface name to its index
+	toName       map[int]string // interface index to its name
+}
+
+var zoneCache = ipv6ZoneCache{
+	toIndex: make(map[string]int),
+	toName:  make(map[int]string),
+}
+
+// update refreshes the network interface information if the cache was last
+// updated more than 1 minute ago, or if force is set. It returns whether the
+// cache was updated.
+func (zc *ipv6ZoneCache) update(ift []net.Interface, force bool) (updated bool) {
+	zc.Lock()
+	defer zc.Unlock()
+	now := time.Now()
+	if !force && zc.lastFetched.After(now.Add(-60*time.Second)) {
+		return false
+	}
+	zc.lastFetched = now
+	if len(ift) == 0 {
+		var err error
+		if ift, err = net.Interfaces(); err != nil {
+			return false
+		}
+	}
+	zc.toIndex = make(map[string]int, len(ift))
+	zc.toName = make(map[int]string, len(ift))
+	for _, ifi := range ift {
+		zc.toIndex[ifi.Name] = ifi.Index
+		if _, ok := zc.toName[ifi.Index]; !ok {
+			zc.toName[ifi.Index] = ifi.Name
+		}
+	}
+	return true
+}
+
+func (zc *ipv6ZoneCache) name(zone int) string {
+	updated := zoneCache.update(nil, false)
+	zoneCache.RLock()
+	name, ok := zoneCache.toName[zone]
+	zoneCache.RUnlock()
+	if !ok && !updated {
+		zoneCache.update(nil, true)
+		zoneCache.RLock()
+		name, ok = zoneCache.toName[zone]
+		zoneCache.RUnlock()
+	}
+	if !ok { // last resort
+		name = strconv.Itoa(zone)
+	}
+	return name
+}
+
+func (zc *ipv6ZoneCache) index(zone string) int {
+	updated := zoneCache.update(nil, false)
+	zoneCache.RLock()
+	index, ok := zoneCache.toIndex[zone]
+	zoneCache.RUnlock()
+	if !ok && !updated {
+		zoneCache.update(nil, true)
+		zoneCache.RLock()
+		index, ok = zoneCache.toIndex[zone]
+		zoneCache.RUnlock()
+	}
+	if !ok { // last resort
+		index, _ = strconv.Atoi(zone)
+	}
+	return index
+}
@@ -0,0 +1,52 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris && !windows && !zos
+
+package socket
+
+import "net"
+
+const (
+	sysAF_UNSPEC = 0x0
+	sysAF_INET   = 0x2
+	sysAF_INET6  = 0xa
+
+	sysSOCK_RAW = 0x3
+
+	sizeofSockaddrInet4 = 0x10
+	sizeofSockaddrInet6 = 0x1c
+)
+
+func marshalInetAddr(ip net.IP, port int, zone string) []byte {
+	return nil
+}
+
+func parseInetAddr(b []byte, network string) (net.Addr, error) {
+	return nil, errNotImplemented
+}
+
+func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
+	return 0, errNotImplemented
+}
+
+func setsockopt(s uintptr, level, name int, b []byte) error {
+	return errNotImplemented
+}
+
+func recvmsg(s uintptr, buffers [][]byte, oob []byte, flags int, network string) (n, oobn int, recvflags int, from net.Addr, err error) {
+	return 0, 0, 0, nil, errNotImplemented
+}
+
+func sendmsg(s uintptr, buffers [][]byte, oob []byte, to net.Addr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
@@ -0,0 +1,121 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package socket
+
+import (
+	"net"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+//go:linkname syscall_getsockopt syscall.getsockopt
+func syscall_getsockopt(s, level, name int, val unsafe.Pointer, vallen *uint32) error
+
+//go:linkname syscall_setsockopt syscall.setsockopt
+func syscall_setsockopt(s, level, name int, val unsafe.Pointer, vallen uintptr) error
+
+func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
+	l := uint32(len(b))
+	err := syscall_getsockopt(int(s), level, name, unsafe.Pointer(&b[0]), &l)
+	return int(l), err
+}
+
+func setsockopt(s uintptr, level, name int, b []byte) error {
+	return syscall_setsockopt(int(s), level, name, unsafe.Pointer(&b[0]), uintptr(len(b)))
+}
+
+func recvmsg(s uintptr, buffers [][]byte, oob []byte, flags int, network string) (n, oobn int, recvflags int, from net.Addr, err error) {
+	var unixFrom unix.Sockaddr
+	n, oobn, recvflags, unixFrom, err = unix.RecvmsgBuffers(int(s), buffers, oob, flags)
+	if unixFrom != nil {
+		from = sockaddrToAddr(unixFrom, network)
+	}
+	return
+}
+
+func sendmsg(s uintptr, buffers [][]byte, oob []byte, to net.Addr, flags int) (int, error) {
+	var unixTo unix.Sockaddr
+	if to != nil {
+		unixTo = addrToSockaddr(to)
+	}
+	return unix.SendmsgBuffers(int(s), buffers, oob, unixTo, flags)
+}
+
+// addrToSockaddr converts a net.Addr to a unix.Sockaddr.
+func addrToSockaddr(a net.Addr) unix.Sockaddr {
+	var (
+		ip   net.IP
+		port int
+		zone string
+	)
+	switch a := a.(type) {
+	case *net.TCPAddr:
+		ip = a.IP
+		port = a.Port
+		zone = a.Zone
+	case *net.UDPAddr:
+		ip = a.IP
+		port = a.Port
+		zone = a.Zone
+	case *net.IPAddr:
+		ip = a.IP
+		zone = a.Zone
+	default:
+		return nil
+	}
+
+	if ip4 := ip.To4(); ip4 != nil {
+		sa := unix.SockaddrInet4{Port: port}
+		copy(sa.Addr[:], ip4)
+		return &sa
+	}
+
+	if ip6 := ip.To16(); ip6 != nil && ip.To4() == nil {
+		sa := unix.SockaddrInet6{Port: port}
+		copy(sa.Addr[:], ip6)
+		if zone != "" {
+			sa.ZoneId = uint32(zoneCache.index(zone))
+		}
+		return &sa
+	}
+
+	return nil
+}
+
+// sockaddrToAddr converts a unix.Sockaddr to a net.Addr.
+func sockaddrToAddr(sa unix.Sockaddr, network string) net.Addr {
+	var (
+		ip   net.IP
+		port int
+		zone string
+	)
+	switch sa := sa.(type) {
+	case *unix.SockaddrInet4:
+		ip = make(net.IP, net.IPv4len)
+		copy(ip, sa.Addr[:])
+		port = sa.Port
+	case *unix.SockaddrInet6:
+		ip = make(net.IP, net.IPv6len)
+		copy(ip, sa.Addr[:])
+		port = sa.Port
+		if sa.ZoneId > 0 {
+			zone = zoneCache.name(int(sa.ZoneId))
+		}
+	default:
+		return nil
+	}
+
+	switch network {
+	case "tcp", "tcp4", "tcp6":
+		return &net.TCPAddr{IP: ip, Port: port, Zone: zone}
+	case "udp", "udp4", "udp6":
+		return &net.UDPAddr{IP: ip, Port: port, Zone: zone}
+	default:
+		return &net.IPAddr{IP: ip, Zone: zone}
+	}
+}
@@ -0,0 +1,55 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"net"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func probeProtocolStack() int {
+	var p uintptr
+	return int(unsafe.Sizeof(p))
+}
+
+const (
+	sysAF_UNSPEC = windows.AF_UNSPEC
+	sysAF_INET   = windows.AF_INET
+	sysAF_INET6  = windows.AF_INET6
+
+	sysSOCK_RAW = windows.SOCK_RAW
+
+	sizeofSockaddrInet4 = 0x10
+	sizeofSockaddrInet6 = 0x1c
+)
+
+func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
+	l := uint32(len(b))
+	err := syscall.Getsockopt(syscall.Handle(s), int32(level), int32(name), (*byte)(unsafe.Pointer(&b[0])), (*int32)(unsafe.Pointer(&l)))
+	return int(l), err
+}
+
+func setsockopt(s uintptr, level, name int, b []byte) error {
+	return syscall.Setsockopt(syscall.Handle(s), int32(level), int32(name), (*byte)(unsafe.Pointer(&b[0])), int32(len(b)))
+}
+
+func recvmsg(s uintptr, buffers [][]byte, oob []byte, flags int, network string) (n, oobn int, recvflags int, from net.Addr, err error) {
+	return 0, 0, 0, nil, errNotImplemented
+}
+
+func sendmsg(s uintptr, buffers [][]byte, oob []byte, to net.Addr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func recvmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
+
+func sendmmsg(s uintptr, hs []mmsghdr, flags int) (int, error) {
+	return 0, errNotImplemented
+}
@@ -0,0 +1,66 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package socket
+
+import (
+	"net"
+	"syscall"
+	"unsafe"
+)
+
+func syscall_syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err syscall.Errno)
+func syscall_syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err syscall.Errno)
+
+func probeProtocolStack() int {
+	return 4 // sizeof(int) on GOOS=zos GOARCH=s390x
+}
+
+func getsockopt(s uintptr, level, name int, b []byte) (int, error) {
+	l := uint32(len(b))
+	_, _, errno := syscall_syscall6(syscall.SYS_GETSOCKOPT, s, uintptr(level), uintptr(name), uintptr(unsafe.Pointer(&b[0])), uintptr(unsafe.Pointer(&l)), 0)
+	return int(l), errnoErr(errno)
+}
+
+func setsockopt(s uintptr, level, name int, b []byte) error {
+	_, _, errno := syscall_syscall6(syscall.SYS_SETSOCKOPT, s, uintptr(level), uintptr(name), uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), 0)
+	return errnoErr(errno)
+}
+
+func recvmsg(s uintptr, buffers [][]byte, oob []byte, flags int, network string) (n, oobn int, recvflags int, from net.Addr, err error) {
+	var h msghdr
+	vs := make([]iovec, len(buffers))
+	var sa []byte
+	if network != "tcp" {
+		sa = make([]byte, sizeofSockaddrInet6)
+	}
+	h.pack(vs, buffers, oob, sa)
+	sn, _, errno := syscall_syscall(syscall.SYS___RECVMSG_A, s, uintptr(unsafe.Pointer(&h)), uintptr(flags))
+	n = int(sn)
+	oobn = h.controllen()
+	recvflags = h.flags()
+	err = errnoErr(errno)
+	if network != "tcp" {
+		var err2 error
+		from, err2 = parseInetAddr(sa, network)
+		if err2 != nil && err == nil {
+			err = err2
+		}
+	}
+	return
+}
+
+func sendmsg(s uintptr, buffers [][]byte, oob []byte, to net.Addr, flags int) (int, error) {
+	var h msghdr
+	vs := make([]iovec, len(buffers))
+	var sa []byte
+	if to != nil {
+		var a [sizeofSockaddrInet6]byte
+		n := marshalInetAddr(to, a[:])
+		sa = a[:n]
+	}
+	h.pack(vs, buffers, oob, sa)
+	n, _, errno := syscall_syscall(syscall.SYS___SENDMSG_A, s, uintptr(unsafe.Pointer(&h)), uintptr(flags))
+	return int(n), errnoErr(errno)
+}
@@ -0,0 +1,11 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+TEXT ·syscall_syscall(SB),NOSPLIT,$0
+        JMP     syscall·_syscall(SB)
+
+TEXT ·syscall_syscall6(SB),NOSPLIT,$0
+        JMP     syscall·_syscall6(SB)
@@ -0,0 +1,39 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_aix.go
+
+// Added for go1.11 compatibility
+//go:build aix
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     int32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type mmsghdr struct {
+	Hdr       msghdr
+	Len       uint32
+	Pad_cgo_0 [4]byte
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,32 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_darwin.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     int32
+	Pad_cgo_1  [4]byte
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,32 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_darwin.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     int32
+	Pad_cgo_1  [4]byte
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,32 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_dragonfly.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     int32
+	Pad_cgo_1  [4]byte
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,30 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_freebsd.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint32
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     int32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x8
+	sizeofMsghdr = 0x1c
+)
@@ -0,0 +1,32 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_freebsd.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     int32
+	Pad_cgo_1  [4]byte
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,30 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_freebsd.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint32
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     int32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x8
+	sizeofMsghdr = 0x1c
+)
@@ -0,0 +1,32 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_freebsd.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     int32
+	Pad_cgo_1  [4]byte
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,30 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_freebsd.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     int32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x30
+)
@@ -0,0 +1,35 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_linux.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint32
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     uint32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type mmsghdr struct {
+	Hdr msghdr
+	Len uint32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x8
+	sizeofMsghdr = 0x1c
+)
@@ -0,0 +1,38 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_linux.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint64
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Pad_cgo_0  [4]byte
+	Iov        *iovec
+	Iovlen     uint64
+	Control    *byte
+	Controllen uint64
+	Flags      int32
+	Pad_cgo_1  [4]byte
+}
+
+type mmsghdr struct {
+	Hdr       msghdr
+	Len       uint32
+	Pad_cgo_0 [4]byte
+}
+
+type cmsghdr struct {
+	Len   uint64
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x10
+	sizeofMsghdr = 0x38
+)
@@ -0,0 +1,35 @@
+// Code generated by cmd/cgo -godefs; DO NOT EDIT.
+// cgo -godefs defs_linux.go
+
+package socket
+
+type iovec struct {
+	Base *byte
+	Len  uint32
+}
+
+type msghdr struct {
+	Name       *byte
+	Namelen    uint32
+	Iov        *iovec
+	Iovlen     uint32
+	Control    *byte
+	Controllen uint32
+	Flags      int32
+}
+
+type mmsghdr struct {
+	Hdr msghdr
+	Len uint32
+}
+
+type cmsghdr struct {
+	Len   uint32
+	Level int32
+	Type  int32
+}
+
+const (
+	sizeofIovec  = 0x8
+	sizeofMsghdr = 0x1c
+)
--- a/Show More
+++ b/Show More