1067 lines
26 KiB
Go
1067 lines
26 KiB
Go
/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
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*/
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package netstack
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import (
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"context"
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"crypto/rand"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"net"
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"os"
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"regexp"
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"strconv"
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"strings"
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"time"
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"golang.zx2c4.com/go118/netip"
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"golang.zx2c4.com/wireguard/tun"
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"golang.org/x/net/dns/dnsmessage"
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"gvisor.dev/gvisor/pkg/tcpip"
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"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
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"gvisor.dev/gvisor/pkg/tcpip/buffer"
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"gvisor.dev/gvisor/pkg/tcpip/header"
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"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
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"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
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"gvisor.dev/gvisor/pkg/tcpip/stack"
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"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
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"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
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"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
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"gvisor.dev/gvisor/pkg/waiter"
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)
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type netTun struct {
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stack *stack.Stack
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dispatcher stack.NetworkDispatcher
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events chan tun.Event
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incomingPacket chan buffer.VectorisedView
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mtu int
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dnsServers []netip.Addr
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hasV4, hasV6 bool
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}
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type (
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endpoint netTun
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Net netTun
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)
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func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
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e.dispatcher = dispatcher
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}
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func (e *endpoint) IsAttached() bool {
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return e.dispatcher != nil
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}
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func (e *endpoint) MTU() uint32 {
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mtu, err := (*netTun)(e).MTU()
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if err != nil {
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panic(err)
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}
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return uint32(mtu)
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}
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func (*endpoint) Capabilities() stack.LinkEndpointCapabilities {
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return stack.CapabilityNone
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}
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func (*endpoint) MaxHeaderLength() uint16 {
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return 0
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}
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func (*endpoint) LinkAddress() tcpip.LinkAddress {
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return ""
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}
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func (*endpoint) Wait() {}
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func (e *endpoint) WritePacket(_ stack.RouteInfo, _ tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) tcpip.Error {
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e.incomingPacket <- buffer.NewVectorisedView(pkt.Size(), pkt.Views())
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return nil
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}
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func (e *endpoint) WritePackets(stack.RouteInfo, stack.PacketBufferList, tcpip.NetworkProtocolNumber) (int, tcpip.Error) {
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panic("not implemented")
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}
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func (e *endpoint) WriteRawPacket(*stack.PacketBuffer) tcpip.Error {
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panic("not implemented")
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}
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func (*endpoint) ARPHardwareType() header.ARPHardwareType {
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return header.ARPHardwareNone
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}
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func (e *endpoint) AddHeader(tcpip.LinkAddress, tcpip.LinkAddress, tcpip.NetworkProtocolNumber, *stack.PacketBuffer) {
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}
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func CreateNetTUN(localAddresses, dnsServers []netip.Addr, mtu int) (tun.Device, *Net, error) {
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opts := stack.Options{
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NetworkProtocols: []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
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TransportProtocols: []stack.TransportProtocolFactory{tcp.NewProtocol, udp.NewProtocol, icmp.NewProtocol6, icmp.NewProtocol4},
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HandleLocal: true,
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}
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dev := &netTun{
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stack: stack.New(opts),
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events: make(chan tun.Event, 10),
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incomingPacket: make(chan buffer.VectorisedView),
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dnsServers: dnsServers,
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mtu: mtu,
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}
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tcpipErr := dev.stack.CreateNIC(1, (*endpoint)(dev))
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if tcpipErr != nil {
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return nil, nil, fmt.Errorf("CreateNIC: %v", tcpipErr)
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}
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for _, ip := range localAddresses {
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var protoNumber tcpip.NetworkProtocolNumber
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if ip.Is4() {
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protoNumber = ipv4.ProtocolNumber
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} else if ip.Is6() {
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protoNumber = ipv6.ProtocolNumber
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}
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protoAddr := tcpip.ProtocolAddress{
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Protocol: protoNumber,
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AddressWithPrefix: tcpip.Address(ip.AsSlice()).WithPrefix(),
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}
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tcpipErr := dev.stack.AddProtocolAddress(1, protoAddr, stack.AddressProperties{})
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if tcpipErr != nil {
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return nil, nil, fmt.Errorf("AddProtocolAddress(%v): %v", ip, tcpipErr)
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}
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if ip.Is4() {
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dev.hasV4 = true
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} else if ip.Is6() {
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dev.hasV6 = true
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}
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}
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if dev.hasV4 {
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dev.stack.AddRoute(tcpip.Route{Destination: header.IPv4EmptySubnet, NIC: 1})
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}
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if dev.hasV6 {
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dev.stack.AddRoute(tcpip.Route{Destination: header.IPv6EmptySubnet, NIC: 1})
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}
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dev.events <- tun.EventUp
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return dev, (*Net)(dev), nil
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}
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func (tun *netTun) Name() (string, error) {
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return "go", nil
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}
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func (tun *netTun) File() *os.File {
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return nil
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}
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func (tun *netTun) Events() chan tun.Event {
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return tun.events
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}
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func (tun *netTun) Read(buf []byte, offset int) (int, error) {
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view, ok := <-tun.incomingPacket
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if !ok {
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return 0, os.ErrClosed
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}
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return view.Read(buf[offset:])
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}
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func (tun *netTun) Write(buf []byte, offset int) (int, error) {
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packet := buf[offset:]
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if len(packet) == 0 {
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return 0, nil
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}
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pkb := stack.NewPacketBuffer(stack.PacketBufferOptions{Data: buffer.NewVectorisedView(len(packet), []buffer.View{buffer.NewViewFromBytes(packet)})})
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switch packet[0] >> 4 {
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case 4:
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tun.dispatcher.DeliverNetworkPacket("", "", ipv4.ProtocolNumber, pkb)
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case 6:
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tun.dispatcher.DeliverNetworkPacket("", "", ipv6.ProtocolNumber, pkb)
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}
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return len(buf), nil
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}
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func (tun *netTun) Flush() error {
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return nil
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}
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func (tun *netTun) Close() error {
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tun.stack.RemoveNIC(1)
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if tun.events != nil {
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close(tun.events)
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}
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if tun.incomingPacket != nil {
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close(tun.incomingPacket)
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}
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return nil
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}
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func (tun *netTun) MTU() (int, error) {
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return tun.mtu, nil
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}
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func convertToFullAddr(endpoint netip.AddrPort) (tcpip.FullAddress, tcpip.NetworkProtocolNumber) {
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var protoNumber tcpip.NetworkProtocolNumber
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if endpoint.Addr().Is4() {
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protoNumber = ipv4.ProtocolNumber
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} else {
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protoNumber = ipv6.ProtocolNumber
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}
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return tcpip.FullAddress{
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NIC: 1,
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Addr: tcpip.Address(endpoint.Addr().AsSlice()),
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Port: endpoint.Port(),
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}, protoNumber
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}
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func (net *Net) DialContextTCPAddrPort(ctx context.Context, addr netip.AddrPort) (*gonet.TCPConn, error) {
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fa, pn := convertToFullAddr(addr)
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return gonet.DialContextTCP(ctx, net.stack, fa, pn)
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}
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func (net *Net) DialContextTCP(ctx context.Context, addr *net.TCPAddr) (*gonet.TCPConn, error) {
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if addr == nil {
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return net.DialContextTCPAddrPort(ctx, netip.AddrPort{})
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}
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return net.DialContextTCPAddrPort(ctx, netip.AddrPortFrom(netip.AddrFromSlice(addr.IP), uint16(addr.Port)))
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}
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func (net *Net) DialTCPAddrPort(addr netip.AddrPort) (*gonet.TCPConn, error) {
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fa, pn := convertToFullAddr(addr)
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return gonet.DialTCP(net.stack, fa, pn)
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}
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func (net *Net) DialTCP(addr *net.TCPAddr) (*gonet.TCPConn, error) {
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if addr == nil {
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return net.DialTCPAddrPort(netip.AddrPort{})
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}
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return net.DialTCPAddrPort(netip.AddrPortFrom(netip.AddrFromSlice(addr.IP), uint16(addr.Port)))
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}
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func (net *Net) ListenTCPAddrPort(addr netip.AddrPort) (*gonet.TCPListener, error) {
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fa, pn := convertToFullAddr(addr)
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return gonet.ListenTCP(net.stack, fa, pn)
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}
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func (net *Net) ListenTCP(addr *net.TCPAddr) (*gonet.TCPListener, error) {
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if addr == nil {
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return net.ListenTCPAddrPort(netip.AddrPort{})
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}
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return net.ListenTCPAddrPort(netip.AddrPortFrom(netip.AddrFromSlice(addr.IP), uint16(addr.Port)))
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}
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func (net *Net) DialUDPAddrPort(laddr, raddr netip.AddrPort) (*gonet.UDPConn, error) {
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var lfa, rfa *tcpip.FullAddress
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var pn tcpip.NetworkProtocolNumber
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if laddr.IsValid() || laddr.Port() > 0 {
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var addr tcpip.FullAddress
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addr, pn = convertToFullAddr(laddr)
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lfa = &addr
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}
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if raddr.IsValid() || raddr.Port() > 0 {
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var addr tcpip.FullAddress
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addr, pn = convertToFullAddr(raddr)
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rfa = &addr
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}
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return gonet.DialUDP(net.stack, lfa, rfa, pn)
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}
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func (net *Net) ListenUDPAddrPort(laddr netip.AddrPort) (*gonet.UDPConn, error) {
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return net.DialUDPAddrPort(laddr, netip.AddrPort{})
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}
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func (net *Net) DialUDP(laddr, raddr *net.UDPAddr) (*gonet.UDPConn, error) {
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var la, ra netip.AddrPort
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if laddr != nil {
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la = netip.AddrPortFrom(netip.AddrFromSlice(laddr.IP), uint16(laddr.Port))
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}
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if raddr != nil {
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ra = netip.AddrPortFrom(netip.AddrFromSlice(raddr.IP), uint16(raddr.Port))
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}
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return net.DialUDPAddrPort(la, ra)
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}
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func (net *Net) ListenUDP(laddr *net.UDPAddr) (*gonet.UDPConn, error) {
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return net.DialUDP(laddr, nil)
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}
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type PingConn struct {
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laddr PingAddr
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raddr PingAddr
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wq waiter.Queue
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ep tcpip.Endpoint
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deadline *time.Timer
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}
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type PingAddr struct{ addr netip.Addr }
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func (ia PingAddr) String() string {
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return ia.addr.String()
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}
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func (ia PingAddr) Network() string {
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if ia.addr.Is4() {
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return "ping4"
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} else if ia.addr.Is6() {
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return "ping6"
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}
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return "ping"
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}
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func (ia PingAddr) Addr() netip.Addr {
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return ia.addr
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}
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func PingAddrFromAddr(addr netip.Addr) *PingAddr {
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return &PingAddr{addr}
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}
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func (net *Net) DialPingAddr(laddr, raddr netip.Addr) (*PingConn, error) {
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if !laddr.IsValid() && !raddr.IsValid() {
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return nil, errors.New("ping dial: invalid address")
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}
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v6 := laddr.Is6() || raddr.Is6()
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bind := laddr.IsValid()
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if !bind {
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if v6 {
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laddr = netip.IPv6Unspecified()
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} else {
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laddr = netip.IPv4Unspecified()
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}
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}
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tn := icmp.ProtocolNumber4
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pn := ipv4.ProtocolNumber
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if v6 {
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tn = icmp.ProtocolNumber6
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pn = ipv6.ProtocolNumber
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}
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pc := &PingConn{
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laddr: PingAddr{laddr},
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deadline: time.NewTimer(time.Hour << 10),
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}
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pc.deadline.Stop()
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ep, tcpipErr := net.stack.NewEndpoint(tn, pn, &pc.wq)
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if tcpipErr != nil {
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return nil, fmt.Errorf("ping socket: endpoint: %s", tcpipErr)
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}
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pc.ep = ep
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if bind {
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fa, _ := convertToFullAddr(netip.AddrPortFrom(laddr, 0))
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if tcpipErr = pc.ep.Bind(fa); tcpipErr != nil {
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return nil, fmt.Errorf("ping bind: %s", tcpipErr)
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}
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}
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if raddr.IsValid() {
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pc.raddr = PingAddr{raddr}
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fa, _ := convertToFullAddr(netip.AddrPortFrom(raddr, 0))
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if tcpipErr = pc.ep.Connect(fa); tcpipErr != nil {
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return nil, fmt.Errorf("ping connect: %s", tcpipErr)
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}
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}
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return pc, nil
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}
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func (net *Net) ListenPingAddr(laddr netip.Addr) (*PingConn, error) {
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return net.DialPingAddr(laddr, netip.Addr{})
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}
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func (net *Net) DialPing(laddr, raddr *PingAddr) (*PingConn, error) {
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var la, ra netip.Addr
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if laddr != nil {
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la = laddr.addr
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}
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if raddr != nil {
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ra = raddr.addr
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}
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return net.DialPingAddr(la, ra)
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}
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func (net *Net) ListenPing(laddr *PingAddr) (*PingConn, error) {
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var la netip.Addr
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if laddr != nil {
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la = laddr.addr
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}
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return net.ListenPingAddr(la)
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}
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func (pc *PingConn) LocalAddr() net.Addr {
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return pc.laddr
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}
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func (pc *PingConn) RemoteAddr() net.Addr {
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return pc.raddr
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}
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func (pc *PingConn) Close() error {
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pc.deadline.Reset(0)
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pc.ep.Close()
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return nil
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}
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func (pc *PingConn) SetWriteDeadline(t time.Time) error {
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return errors.New("not implemented")
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}
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func (pc *PingConn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
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var na netip.Addr
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switch v := addr.(type) {
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case *PingAddr:
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na = v.addr
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case *net.IPAddr:
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na = netip.AddrFromSlice(v.IP)
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default:
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return 0, fmt.Errorf("ping write: wrong net.Addr type")
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}
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if !((na.Is4() && pc.laddr.addr.Is4()) || (na.Is6() && pc.laddr.addr.Is6())) {
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return 0, fmt.Errorf("ping write: mismatched protocols")
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}
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buf := buffer.NewViewFromBytes(p)
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rdr := buf.Reader()
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rfa, _ := convertToFullAddr(netip.AddrPortFrom(na, 0))
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// won't block, no deadlines
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n64, tcpipErr := pc.ep.Write(&rdr, tcpip.WriteOptions{
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To: &rfa,
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})
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if tcpipErr != nil {
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return int(n64), fmt.Errorf("ping write: %s", tcpipErr)
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}
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return int(n64), nil
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}
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func (pc *PingConn) Write(p []byte) (n int, err error) {
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return pc.WriteTo(p, &pc.raddr)
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}
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func (pc *PingConn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
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e, notifyCh := waiter.NewChannelEntry(nil)
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pc.wq.EventRegister(&e, waiter.EventIn)
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defer pc.wq.EventUnregister(&e)
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select {
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case <-pc.deadline.C:
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return 0, nil, os.ErrDeadlineExceeded
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case <-notifyCh:
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}
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w := tcpip.SliceWriter(p)
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res, tcpipErr := pc.ep.Read(&w, tcpip.ReadOptions{
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NeedRemoteAddr: true,
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})
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if tcpipErr != nil {
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return 0, nil, fmt.Errorf("ping read: %s", tcpipErr)
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}
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|
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addr = &PingAddr{netip.AddrFromSlice([]byte(res.RemoteAddr.Addr))}
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return res.Count, addr, nil
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}
|
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|
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func (pc *PingConn) Read(p []byte) (n int, err error) {
|
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n, _, err = pc.ReadFrom(p)
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return
|
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}
|
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|
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func (pc *PingConn) SetDeadline(t time.Time) error {
|
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// pc.SetWriteDeadline is unimplemented
|
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|
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return pc.SetReadDeadline(t)
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}
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|
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func (pc *PingConn) SetReadDeadline(t time.Time) error {
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pc.deadline.Reset(t.Sub(time.Now()))
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return nil
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}
|
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|
|
var (
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errNoSuchHost = errors.New("no such host")
|
|
errLameReferral = errors.New("lame referral")
|
|
errCannotUnmarshalDNSMessage = errors.New("cannot unmarshal DNS message")
|
|
errCannotMarshalDNSMessage = errors.New("cannot marshal DNS message")
|
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errServerMisbehaving = errors.New("server misbehaving")
|
|
errInvalidDNSResponse = errors.New("invalid DNS response")
|
|
errNoAnswerFromDNSServer = errors.New("no answer from DNS server")
|
|
errServerTemporarilyMisbehaving = errors.New("server misbehaving")
|
|
errCanceled = errors.New("operation was canceled")
|
|
errTimeout = errors.New("i/o timeout")
|
|
errNumericPort = errors.New("port must be numeric")
|
|
errNoSuitableAddress = errors.New("no suitable address found")
|
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errMissingAddress = errors.New("missing address")
|
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)
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|
|
func (net *Net) LookupHost(host string) (addrs []string, err error) {
|
|
return net.LookupContextHost(context.Background(), host)
|
|
}
|
|
|
|
func isDomainName(s string) bool {
|
|
l := len(s)
|
|
if l == 0 || l > 254 || l == 254 && s[l-1] != '.' {
|
|
return false
|
|
}
|
|
last := byte('.')
|
|
nonNumeric := false
|
|
partlen := 0
|
|
for i := 0; i < len(s); i++ {
|
|
c := s[i]
|
|
switch {
|
|
default:
|
|
return false
|
|
case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_':
|
|
nonNumeric = true
|
|
partlen++
|
|
case '0' <= c && c <= '9':
|
|
partlen++
|
|
case c == '-':
|
|
if last == '.' {
|
|
return false
|
|
}
|
|
partlen++
|
|
nonNumeric = true
|
|
case c == '.':
|
|
if last == '.' || last == '-' {
|
|
return false
|
|
}
|
|
if partlen > 63 || partlen == 0 {
|
|
return false
|
|
}
|
|
partlen = 0
|
|
}
|
|
last = c
|
|
}
|
|
if last == '-' || partlen > 63 {
|
|
return false
|
|
}
|
|
return nonNumeric
|
|
}
|
|
|
|
func randU16() uint16 {
|
|
var b [2]byte
|
|
_, err := rand.Read(b[:])
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return binary.LittleEndian.Uint16(b[:])
|
|
}
|
|
|
|
func newRequest(q dnsmessage.Question) (id uint16, udpReq, tcpReq []byte, err error) {
|
|
id = randU16()
|
|
b := dnsmessage.NewBuilder(make([]byte, 2, 514), dnsmessage.Header{ID: id, RecursionDesired: true})
|
|
b.EnableCompression()
|
|
if err := b.StartQuestions(); err != nil {
|
|
return 0, nil, nil, err
|
|
}
|
|
if err := b.Question(q); err != nil {
|
|
return 0, nil, nil, err
|
|
}
|
|
tcpReq, err = b.Finish()
|
|
udpReq = tcpReq[2:]
|
|
l := len(tcpReq) - 2
|
|
tcpReq[0] = byte(l >> 8)
|
|
tcpReq[1] = byte(l)
|
|
return id, udpReq, tcpReq, err
|
|
}
|
|
|
|
func equalASCIIName(x, y dnsmessage.Name) bool {
|
|
if x.Length != y.Length {
|
|
return false
|
|
}
|
|
for i := 0; i < int(x.Length); i++ {
|
|
a := x.Data[i]
|
|
b := y.Data[i]
|
|
if 'A' <= a && a <= 'Z' {
|
|
a += 0x20
|
|
}
|
|
if 'A' <= b && b <= 'Z' {
|
|
b += 0x20
|
|
}
|
|
if a != b {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func checkResponse(reqID uint16, reqQues dnsmessage.Question, respHdr dnsmessage.Header, respQues dnsmessage.Question) bool {
|
|
if !respHdr.Response {
|
|
return false
|
|
}
|
|
if reqID != respHdr.ID {
|
|
return false
|
|
}
|
|
if reqQues.Type != respQues.Type || reqQues.Class != respQues.Class || !equalASCIIName(reqQues.Name, respQues.Name) {
|
|
return false
|
|
}
|
|
return true
|
|
}
|
|
|
|
func dnsPacketRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
|
|
if _, err := c.Write(b); err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
b = make([]byte, 512)
|
|
for {
|
|
n, err := c.Read(b)
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
var p dnsmessage.Parser
|
|
h, err := p.Start(b[:n])
|
|
if err != nil {
|
|
continue
|
|
}
|
|
q, err := p.Question()
|
|
if err != nil || !checkResponse(id, query, h, q) {
|
|
continue
|
|
}
|
|
return p, h, nil
|
|
}
|
|
}
|
|
|
|
func dnsStreamRoundTrip(c net.Conn, id uint16, query dnsmessage.Question, b []byte) (dnsmessage.Parser, dnsmessage.Header, error) {
|
|
if _, err := c.Write(b); err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
b = make([]byte, 1280)
|
|
if _, err := io.ReadFull(c, b[:2]); err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
l := int(b[0])<<8 | int(b[1])
|
|
if l > len(b) {
|
|
b = make([]byte, l)
|
|
}
|
|
n, err := io.ReadFull(c, b[:l])
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
var p dnsmessage.Parser
|
|
h, err := p.Start(b[:n])
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
|
|
}
|
|
q, err := p.Question()
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotUnmarshalDNSMessage
|
|
}
|
|
if !checkResponse(id, query, h, q) {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
|
|
}
|
|
return p, h, nil
|
|
}
|
|
|
|
func (tnet *Net) exchange(ctx context.Context, server netip.Addr, q dnsmessage.Question, timeout time.Duration) (dnsmessage.Parser, dnsmessage.Header, error) {
|
|
q.Class = dnsmessage.ClassINET
|
|
id, udpReq, tcpReq, err := newRequest(q)
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errCannotMarshalDNSMessage
|
|
}
|
|
|
|
for _, useUDP := range []bool{true, false} {
|
|
ctx, cancel := context.WithDeadline(ctx, time.Now().Add(timeout))
|
|
defer cancel()
|
|
|
|
var c net.Conn
|
|
var err error
|
|
if useUDP {
|
|
c, err = tnet.DialUDPAddrPort(netip.AddrPort{}, netip.AddrPortFrom(server, 53))
|
|
} else {
|
|
c, err = tnet.DialContextTCPAddrPort(ctx, netip.AddrPortFrom(server, 53))
|
|
}
|
|
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
if d, ok := ctx.Deadline(); ok && !d.IsZero() {
|
|
c.SetDeadline(d)
|
|
}
|
|
var p dnsmessage.Parser
|
|
var h dnsmessage.Header
|
|
if useUDP {
|
|
p, h, err = dnsPacketRoundTrip(c, id, q, udpReq)
|
|
} else {
|
|
p, h, err = dnsStreamRoundTrip(c, id, q, tcpReq)
|
|
}
|
|
c.Close()
|
|
if err != nil {
|
|
if err == context.Canceled {
|
|
err = errCanceled
|
|
} else if err == context.DeadlineExceeded {
|
|
err = errTimeout
|
|
}
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, err
|
|
}
|
|
if err := p.SkipQuestion(); err != dnsmessage.ErrSectionDone {
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errInvalidDNSResponse
|
|
}
|
|
if h.Truncated {
|
|
continue
|
|
}
|
|
return p, h, nil
|
|
}
|
|
return dnsmessage.Parser{}, dnsmessage.Header{}, errNoAnswerFromDNSServer
|
|
}
|
|
|
|
func checkHeader(p *dnsmessage.Parser, h dnsmessage.Header) error {
|
|
if h.RCode == dnsmessage.RCodeNameError {
|
|
return errNoSuchHost
|
|
}
|
|
_, err := p.AnswerHeader()
|
|
if err != nil && err != dnsmessage.ErrSectionDone {
|
|
return errCannotUnmarshalDNSMessage
|
|
}
|
|
if h.RCode == dnsmessage.RCodeSuccess && !h.Authoritative && !h.RecursionAvailable && err == dnsmessage.ErrSectionDone {
|
|
return errLameReferral
|
|
}
|
|
if h.RCode != dnsmessage.RCodeSuccess && h.RCode != dnsmessage.RCodeNameError {
|
|
if h.RCode == dnsmessage.RCodeServerFailure {
|
|
return errServerTemporarilyMisbehaving
|
|
}
|
|
return errServerMisbehaving
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func skipToAnswer(p *dnsmessage.Parser, qtype dnsmessage.Type) error {
|
|
for {
|
|
h, err := p.AnswerHeader()
|
|
if err == dnsmessage.ErrSectionDone {
|
|
return errNoSuchHost
|
|
}
|
|
if err != nil {
|
|
return errCannotUnmarshalDNSMessage
|
|
}
|
|
if h.Type == qtype {
|
|
return nil
|
|
}
|
|
if err := p.SkipAnswer(); err != nil {
|
|
return errCannotUnmarshalDNSMessage
|
|
}
|
|
}
|
|
}
|
|
|
|
func (tnet *Net) tryOneName(ctx context.Context, name string, qtype dnsmessage.Type) (dnsmessage.Parser, string, error) {
|
|
var lastErr error
|
|
|
|
n, err := dnsmessage.NewName(name)
|
|
if err != nil {
|
|
return dnsmessage.Parser{}, "", errCannotMarshalDNSMessage
|
|
}
|
|
q := dnsmessage.Question{
|
|
Name: n,
|
|
Type: qtype,
|
|
Class: dnsmessage.ClassINET,
|
|
}
|
|
|
|
for i := 0; i < 2; i++ {
|
|
for _, server := range tnet.dnsServers {
|
|
p, h, err := tnet.exchange(ctx, server, q, time.Second*5)
|
|
if err != nil {
|
|
dnsErr := &net.DNSError{
|
|
Err: err.Error(),
|
|
Name: name,
|
|
Server: server.String(),
|
|
}
|
|
if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
|
|
dnsErr.IsTimeout = true
|
|
}
|
|
if _, ok := err.(*net.OpError); ok {
|
|
dnsErr.IsTemporary = true
|
|
}
|
|
lastErr = dnsErr
|
|
continue
|
|
}
|
|
|
|
if err := checkHeader(&p, h); err != nil {
|
|
dnsErr := &net.DNSError{
|
|
Err: err.Error(),
|
|
Name: name,
|
|
Server: server.String(),
|
|
}
|
|
if err == errServerTemporarilyMisbehaving {
|
|
dnsErr.IsTemporary = true
|
|
}
|
|
if err == errNoSuchHost {
|
|
dnsErr.IsNotFound = true
|
|
return p, server.String(), dnsErr
|
|
}
|
|
lastErr = dnsErr
|
|
continue
|
|
}
|
|
|
|
err = skipToAnswer(&p, qtype)
|
|
if err == nil {
|
|
return p, server.String(), nil
|
|
}
|
|
lastErr = &net.DNSError{
|
|
Err: err.Error(),
|
|
Name: name,
|
|
Server: server.String(),
|
|
}
|
|
if err == errNoSuchHost {
|
|
lastErr.(*net.DNSError).IsNotFound = true
|
|
return p, server.String(), lastErr
|
|
}
|
|
}
|
|
}
|
|
return dnsmessage.Parser{}, "", lastErr
|
|
}
|
|
|
|
func (tnet *Net) LookupContextHost(ctx context.Context, host string) ([]string, error) {
|
|
if host == "" || (!tnet.hasV6 && !tnet.hasV4) {
|
|
return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
|
|
}
|
|
zlen := len(host)
|
|
if strings.IndexByte(host, ':') != -1 {
|
|
if zidx := strings.LastIndexByte(host, '%'); zidx != -1 {
|
|
zlen = zidx
|
|
}
|
|
}
|
|
if ip, err := netip.ParseAddr(host[:zlen]); err == nil {
|
|
return []string{ip.String()}, nil
|
|
}
|
|
|
|
if !isDomainName(host) {
|
|
return nil, &net.DNSError{Err: errNoSuchHost.Error(), Name: host, IsNotFound: true}
|
|
}
|
|
type result struct {
|
|
p dnsmessage.Parser
|
|
server string
|
|
error
|
|
}
|
|
var addrsV4, addrsV6 []netip.Addr
|
|
lanes := 0
|
|
if tnet.hasV4 {
|
|
lanes++
|
|
}
|
|
if tnet.hasV6 {
|
|
lanes++
|
|
}
|
|
lane := make(chan result, lanes)
|
|
var lastErr error
|
|
if tnet.hasV4 {
|
|
go func() {
|
|
p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeA)
|
|
lane <- result{p, server, err}
|
|
}()
|
|
}
|
|
if tnet.hasV6 {
|
|
go func() {
|
|
p, server, err := tnet.tryOneName(ctx, host+".", dnsmessage.TypeAAAA)
|
|
lane <- result{p, server, err}
|
|
}()
|
|
}
|
|
for l := 0; l < lanes; l++ {
|
|
result := <-lane
|
|
if result.error != nil {
|
|
if lastErr == nil {
|
|
lastErr = result.error
|
|
}
|
|
continue
|
|
}
|
|
|
|
loop:
|
|
for {
|
|
h, err := result.p.AnswerHeader()
|
|
if err != nil && err != dnsmessage.ErrSectionDone {
|
|
lastErr = &net.DNSError{
|
|
Err: errCannotMarshalDNSMessage.Error(),
|
|
Name: host,
|
|
Server: result.server,
|
|
}
|
|
}
|
|
if err != nil {
|
|
break
|
|
}
|
|
switch h.Type {
|
|
case dnsmessage.TypeA:
|
|
a, err := result.p.AResource()
|
|
if err != nil {
|
|
lastErr = &net.DNSError{
|
|
Err: errCannotMarshalDNSMessage.Error(),
|
|
Name: host,
|
|
Server: result.server,
|
|
}
|
|
break loop
|
|
}
|
|
addrsV4 = append(addrsV4, netip.AddrFrom4(a.A))
|
|
|
|
case dnsmessage.TypeAAAA:
|
|
aaaa, err := result.p.AAAAResource()
|
|
if err != nil {
|
|
lastErr = &net.DNSError{
|
|
Err: errCannotMarshalDNSMessage.Error(),
|
|
Name: host,
|
|
Server: result.server,
|
|
}
|
|
break loop
|
|
}
|
|
addrsV6 = append(addrsV6, netip.AddrFrom16(aaaa.AAAA))
|
|
|
|
default:
|
|
if err := result.p.SkipAnswer(); err != nil {
|
|
lastErr = &net.DNSError{
|
|
Err: errCannotMarshalDNSMessage.Error(),
|
|
Name: host,
|
|
Server: result.server,
|
|
}
|
|
break loop
|
|
}
|
|
continue
|
|
}
|
|
}
|
|
}
|
|
// We don't do RFC6724. Instead just put V6 addresess first if an IPv6 address is enabled
|
|
var addrs []netip.Addr
|
|
if tnet.hasV6 {
|
|
addrs = append(addrsV6, addrsV4...)
|
|
} else {
|
|
addrs = append(addrsV4, addrsV6...)
|
|
}
|
|
|
|
if len(addrs) == 0 && lastErr != nil {
|
|
return nil, lastErr
|
|
}
|
|
saddrs := make([]string, 0, len(addrs))
|
|
for _, ip := range addrs {
|
|
saddrs = append(saddrs, ip.String())
|
|
}
|
|
return saddrs, nil
|
|
}
|
|
|
|
func partialDeadline(now, deadline time.Time, addrsRemaining int) (time.Time, error) {
|
|
if deadline.IsZero() {
|
|
return deadline, nil
|
|
}
|
|
timeRemaining := deadline.Sub(now)
|
|
if timeRemaining <= 0 {
|
|
return time.Time{}, errTimeout
|
|
}
|
|
timeout := timeRemaining / time.Duration(addrsRemaining)
|
|
const saneMinimum = 2 * time.Second
|
|
if timeout < saneMinimum {
|
|
if timeRemaining < saneMinimum {
|
|
timeout = timeRemaining
|
|
} else {
|
|
timeout = saneMinimum
|
|
}
|
|
}
|
|
return now.Add(timeout), nil
|
|
}
|
|
|
|
var protoSplitter = regexp.MustCompile(`^(tcp|udp|ping)(4|6)?$`)
|
|
|
|
func (tnet *Net) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
|
|
if ctx == nil {
|
|
panic("nil context")
|
|
}
|
|
var acceptV4, acceptV6 bool
|
|
matches := protoSplitter.FindStringSubmatch(network)
|
|
if matches == nil {
|
|
return nil, &net.OpError{Op: "dial", Err: net.UnknownNetworkError(network)}
|
|
} else if len(matches[2]) == 0 {
|
|
acceptV4 = true
|
|
acceptV6 = true
|
|
} else {
|
|
acceptV4 = matches[2][0] == '4'
|
|
acceptV6 = !acceptV4
|
|
}
|
|
var host string
|
|
var port int
|
|
if matches[1] == "ping" {
|
|
host = address
|
|
} else {
|
|
var sport string
|
|
var err error
|
|
host, sport, err = net.SplitHostPort(address)
|
|
if err != nil {
|
|
return nil, &net.OpError{Op: "dial", Err: err}
|
|
}
|
|
port, err = strconv.Atoi(sport)
|
|
if err != nil || port < 0 || port > 65535 {
|
|
return nil, &net.OpError{Op: "dial", Err: errNumericPort}
|
|
}
|
|
}
|
|
allAddr, err := tnet.LookupContextHost(ctx, host)
|
|
if err != nil {
|
|
return nil, &net.OpError{Op: "dial", Err: err}
|
|
}
|
|
var addrs []netip.AddrPort
|
|
for _, addr := range allAddr {
|
|
ip, err := netip.ParseAddr(addr)
|
|
if err == nil && ((ip.Is4() && acceptV4) || (ip.Is6() && acceptV6)) {
|
|
addrs = append(addrs, netip.AddrPortFrom(ip, uint16(port)))
|
|
}
|
|
}
|
|
if len(addrs) == 0 && len(allAddr) != 0 {
|
|
return nil, &net.OpError{Op: "dial", Err: errNoSuitableAddress}
|
|
}
|
|
|
|
var firstErr error
|
|
for i, addr := range addrs {
|
|
select {
|
|
case <-ctx.Done():
|
|
err := ctx.Err()
|
|
if err == context.Canceled {
|
|
err = errCanceled
|
|
} else if err == context.DeadlineExceeded {
|
|
err = errTimeout
|
|
}
|
|
return nil, &net.OpError{Op: "dial", Err: err}
|
|
default:
|
|
}
|
|
|
|
dialCtx := ctx
|
|
if deadline, hasDeadline := ctx.Deadline(); hasDeadline {
|
|
partialDeadline, err := partialDeadline(time.Now(), deadline, len(addrs)-i)
|
|
if err != nil {
|
|
if firstErr == nil {
|
|
firstErr = &net.OpError{Op: "dial", Err: err}
|
|
}
|
|
break
|
|
}
|
|
if partialDeadline.Before(deadline) {
|
|
var cancel context.CancelFunc
|
|
dialCtx, cancel = context.WithDeadline(ctx, partialDeadline)
|
|
defer cancel()
|
|
}
|
|
}
|
|
|
|
var c net.Conn
|
|
switch matches[1] {
|
|
case "tcp":
|
|
c, err = tnet.DialContextTCPAddrPort(dialCtx, addr)
|
|
case "udp":
|
|
c, err = tnet.DialUDPAddrPort(netip.AddrPort{}, addr)
|
|
case "ping":
|
|
c, err = tnet.DialPingAddr(netip.Addr{}, addr.Addr())
|
|
}
|
|
if err == nil {
|
|
return c, nil
|
|
}
|
|
if firstErr == nil {
|
|
firstErr = err
|
|
}
|
|
}
|
|
if firstErr == nil {
|
|
firstErr = &net.OpError{Op: "dial", Err: errMissingAddress}
|
|
}
|
|
return nil, firstErr
|
|
}
|
|
|
|
func (tnet *Net) Dial(network, address string) (net.Conn, error) {
|
|
return tnet.DialContext(context.Background(), network, address)
|
|
}
|