mirror of
https://github.com/tailscale/tailscale.git
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1302bd1181
Run `staticcheck` with `U1000` to find unused code. This cleans up about a half of it. I'll do the other half separately to keep PRs manageable. Updates #cleanup Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
875 lines
20 KiB
Go
875 lines
20 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package natlab lets us simulate different types of networks all
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// in-memory without running VMs or requiring root, etc. Despite the
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// name, it does more than just NATs. But NATs are the most
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// interesting.
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package natlab
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import (
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"bytes"
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"context"
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"crypto/sha256"
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"encoding/base64"
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"errors"
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"fmt"
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"math/rand"
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"net"
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"net/netip"
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"os"
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"sort"
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"strconv"
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"sync"
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"time"
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"tailscale.com/net/netaddr"
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)
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var traceOn, _ = strconv.ParseBool(os.Getenv("NATLAB_TRACE"))
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// Packet represents a UDP packet flowing through the virtual network.
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type Packet struct {
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Src, Dst netip.AddrPort
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Payload []byte
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// Prefix set by various internal methods of natlab, to locate
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// where in the network a trace occurred.
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locator string
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}
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// Equivalent returns true if Src, Dst and Payload are the same in p
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// and p2.
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func (p *Packet) Equivalent(p2 *Packet) bool {
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return p.Src == p2.Src && p.Dst == p2.Dst && bytes.Equal(p.Payload, p2.Payload)
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}
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// Clone returns a copy of p that shares nothing with p.
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func (p *Packet) Clone() *Packet {
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return &Packet{
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Src: p.Src,
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Dst: p.Dst,
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Payload: bytes.Clone(p.Payload),
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locator: p.locator,
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}
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}
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// short returns a short identifier for a packet payload,
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// suitable for printing trace information.
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func (p *Packet) short() string {
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s := sha256.Sum256(p.Payload)
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payload := base64.RawStdEncoding.EncodeToString(s[:])[:2]
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s = sha256.Sum256([]byte(p.Src.String() + "_" + p.Dst.String()))
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tuple := base64.RawStdEncoding.EncodeToString(s[:])[:2]
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return fmt.Sprintf("%s/%s", payload, tuple)
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}
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func (p *Packet) Trace(msg string, args ...any) {
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if !traceOn {
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return
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}
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allArgs := []any{p.short(), p.locator, p.Src, p.Dst}
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allArgs = append(allArgs, args...)
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fmt.Fprintf(os.Stderr, "[%s]%s src=%s dst=%s "+msg+"\n", allArgs...)
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}
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func (p *Packet) setLocator(msg string, args ...any) {
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p.locator = fmt.Sprintf(" "+msg, args...)
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}
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func mustPrefix(s string) netip.Prefix {
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ipp, err := netip.ParsePrefix(s)
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if err != nil {
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panic(err)
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}
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return ipp
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}
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// NewInternet returns a network that simulates the internet.
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func NewInternet() *Network {
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return &Network{
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Name: "internet",
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// easily recognizable internetty addresses
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Prefix4: mustPrefix("1.0.0.0/24"),
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Prefix6: mustPrefix("1111::/64"),
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}
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}
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type Network struct {
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Name string
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Prefix4 netip.Prefix
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Prefix6 netip.Prefix
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mu sync.Mutex
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machine map[netip.Addr]*Interface
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defaultGW *Interface // optional
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lastV4 netip.Addr
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lastV6 netip.Addr
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}
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func (n *Network) SetDefaultGateway(gwIf *Interface) {
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n.mu.Lock()
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defer n.mu.Unlock()
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if gwIf.net != n {
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panic(fmt.Sprintf("can't set if=%s as net=%s's default gw, if not connected to net", gwIf.name, gwIf.net.Name))
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}
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n.defaultGW = gwIf
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}
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func (n *Network) addMachineLocked(ip netip.Addr, iface *Interface) {
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if iface == nil {
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return // for tests
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}
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if n.machine == nil {
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n.machine = map[netip.Addr]*Interface{}
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}
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n.machine[ip] = iface
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}
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func (n *Network) allocIPv4(iface *Interface) netip.Addr {
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n.mu.Lock()
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defer n.mu.Unlock()
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if !n.Prefix4.IsValid() {
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return netip.Addr{}
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}
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if !n.lastV4.IsValid() {
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n.lastV4 = n.Prefix4.Addr()
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}
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a := n.lastV4.As16()
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addOne(&a, 15)
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n.lastV4 = netip.AddrFrom16(a).Unmap()
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if !n.Prefix4.Contains(n.lastV4) {
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panic("pool exhausted")
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}
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n.addMachineLocked(n.lastV4, iface)
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return n.lastV4
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}
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func (n *Network) allocIPv6(iface *Interface) netip.Addr {
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n.mu.Lock()
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defer n.mu.Unlock()
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if !n.Prefix6.IsValid() {
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return netip.Addr{}
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}
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if !n.lastV6.IsValid() {
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n.lastV6 = n.Prefix6.Addr()
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}
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a := n.lastV6.As16()
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addOne(&a, 15)
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n.lastV6 = netip.AddrFrom16(a).Unmap()
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if !n.Prefix6.Contains(n.lastV6) {
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panic("pool exhausted")
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}
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n.addMachineLocked(n.lastV6, iface)
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return n.lastV6
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}
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func addOne(a *[16]byte, index int) {
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if v := a[index]; v < 255 {
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a[index]++
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} else {
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a[index] = 0
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addOne(a, index-1)
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}
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}
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func (n *Network) write(p *Packet) (num int, err error) {
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p.setLocator("net=%s", n.Name)
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n.mu.Lock()
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defer n.mu.Unlock()
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iface, ok := n.machine[p.Dst.Addr()]
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if !ok {
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// If the destination is within the network's authoritative
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// range, no route to host.
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if p.Dst.Addr().Is4() && n.Prefix4.Contains(p.Dst.Addr()) {
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p.Trace("no route to %v", p.Dst.Addr())
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return len(p.Payload), nil
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}
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if p.Dst.Addr().Is6() && n.Prefix6.Contains(p.Dst.Addr()) {
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p.Trace("no route to %v", p.Dst.Addr())
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return len(p.Payload), nil
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}
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if n.defaultGW == nil {
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p.Trace("no route to %v", p.Dst.Addr())
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return len(p.Payload), nil
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}
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iface = n.defaultGW
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}
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// Pretend it went across the network. Make a copy so nobody
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// can later mess with caller's memory.
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p.Trace("-> mach=%s if=%s", iface.machine.Name, iface.name)
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go iface.machine.deliverIncomingPacket(p, iface)
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return len(p.Payload), nil
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}
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type Interface struct {
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machine *Machine
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net *Network
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name string // optional
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ips []netip.Addr // static; not mutated once created
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}
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func (f *Interface) Machine() *Machine {
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return f.machine
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}
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func (f *Interface) Network() *Network {
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return f.net
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}
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// V4 returns the machine's first IPv4 address, or the zero value if none.
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func (f *Interface) V4() netip.Addr { return f.pickIP(netip.Addr.Is4) }
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// V6 returns the machine's first IPv6 address, or the zero value if none.
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func (f *Interface) V6() netip.Addr { return f.pickIP(netip.Addr.Is6) }
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func (f *Interface) pickIP(pred func(netip.Addr) bool) netip.Addr {
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for _, ip := range f.ips {
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if pred(ip) {
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return ip
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}
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}
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return netip.Addr{}
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}
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func (f *Interface) String() string {
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// TODO: make this all better
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if f.name != "" {
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return f.name
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}
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return fmt.Sprintf("unnamed-interface-on-network-%p", f.net)
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}
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// Contains reports whether f contains ip as an IP.
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func (f *Interface) Contains(ip netip.Addr) bool {
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for _, v := range f.ips {
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if ip == v {
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return true
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}
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}
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return false
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}
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type routeEntry struct {
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prefix netip.Prefix
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iface *Interface
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}
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// A PacketVerdict is a decision of what to do with a packet.
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type PacketVerdict int
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const (
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// Continue means the packet should be processed by the "local
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// sockets" logic of the Machine.
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Continue PacketVerdict = iota
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// Drop means the packet should not be handled further.
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Drop
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)
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func (v PacketVerdict) String() string {
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switch v {
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case Continue:
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return "Continue"
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case Drop:
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return "Drop"
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default:
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return fmt.Sprintf("<unknown verdict %d>", v)
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}
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}
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// A PacketHandler can look at packets arriving at, departing, and
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// transiting a Machine, and filter or mutate them.
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//
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// Each method is invoked with a Packet that natlab would like to keep
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// processing. Handlers can return that same Packet to allow
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// processing to continue; nil to drop the Packet; or a different
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// Packet that should be processed instead of the original.
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//
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// Packets passed to handlers share no state with anything else, and
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// are therefore safe to mutate. It's safe to return the original
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// packet mutated in-place, or a brand new packet initialized from
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// scratch.
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//
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// Packets mutated by a PacketHandler are processed anew by the
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// associated Machine, as if the packet had always been the mutated
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// one. For example, if HandleForward is invoked with a Packet, and
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// the handler changes the destination IP address to one of the
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// Machine's own IPs, the Machine restarts delivery, but this time
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// going to a local PacketConn (which in turn will invoke HandleIn,
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// since the packet is now destined for local delivery).
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type PacketHandler interface {
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// HandleIn processes a packet arriving on iif, whose destination
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// is an IP address owned by the attached Machine. If p is
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// returned unmodified, the Machine will go on to deliver the
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// Packet to the appropriate listening PacketConn, if one exists.
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HandleIn(p *Packet, iif *Interface) *Packet
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// HandleOut processes a packet about to depart on oif from a
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// local PacketConn. If p is returned unmodified, the Machine will
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// transmit the Packet on oif.
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HandleOut(p *Packet, oif *Interface) *Packet
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// HandleForward is called when the Machine wants to forward a
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// packet from iif to oif. If p is returned unmodified, the
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// Machine will transmit the packet on oif.
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HandleForward(p *Packet, iif, oif *Interface) *Packet
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}
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// A Machine is a representation of an operating system's network
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// stack. It has a network routing table and can have multiple
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// attached networks. The zero value is valid, but lacks any
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// networking capability until Attach is called.
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type Machine struct {
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// Name is a pretty name for debugging and packet tracing. It need
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// not be globally unique.
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Name string
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// PacketHandler, if not nil, is a PacketHandler implementation
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// that inspects all packets arriving, departing, or transiting
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// the Machine. See the definition of the PacketHandler interface
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// for semantics.
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//
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// If PacketHandler is nil, the machine allows all inbound
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// traffic, all outbound traffic, and drops forwarded packets.
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PacketHandler PacketHandler
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mu sync.Mutex
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interfaces []*Interface
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routes []routeEntry // sorted by longest prefix to shortest
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conns4 map[netip.AddrPort]*conn // conns that want IPv4 packets
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conns6 map[netip.AddrPort]*conn // conns that want IPv6 packets
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}
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func (m *Machine) isLocalIP(ip netip.Addr) bool {
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m.mu.Lock()
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defer m.mu.Unlock()
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for _, intf := range m.interfaces {
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for _, iip := range intf.ips {
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if ip == iip {
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return true
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}
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}
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}
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return false
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}
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func (m *Machine) deliverIncomingPacket(p *Packet, iface *Interface) {
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p.setLocator("mach=%s if=%s", m.Name, iface.name)
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if m.isLocalIP(p.Dst.Addr()) {
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m.deliverLocalPacket(p, iface)
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} else {
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m.forwardPacket(p, iface)
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}
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}
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func (m *Machine) deliverLocalPacket(p *Packet, iface *Interface) {
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// TODO: can't hold lock while handling packet. This is safe as
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// long as you set HandlePacket before traffic starts flowing.
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if m.PacketHandler != nil {
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p2 := m.PacketHandler.HandleIn(p.Clone(), iface)
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if p2 == nil {
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// Packet dropped, nothing left to do.
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return
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}
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if !p.Equivalent(p2) {
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// Restart delivery, this packet might be a forward packet
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// now.
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m.deliverIncomingPacket(p2, iface)
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return
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}
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}
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m.mu.Lock()
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defer m.mu.Unlock()
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conns := m.conns4
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if p.Dst.Addr().Is6() {
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conns = m.conns6
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}
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possibleDsts := []netip.AddrPort{
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p.Dst,
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netip.AddrPortFrom(v6unspec, p.Dst.Port()),
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netip.AddrPortFrom(v4unspec, p.Dst.Port()),
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}
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for _, dest := range possibleDsts {
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c, ok := conns[dest]
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if !ok {
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continue
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}
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select {
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case c.in <- p:
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p.Trace("queued to conn")
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default:
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p.Trace("dropped, queue overflow")
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// Queue overflow. Just drop it.
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}
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return
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}
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p.Trace("dropped, no listening conn")
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}
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func (m *Machine) forwardPacket(p *Packet, iif *Interface) {
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oif, err := m.interfaceForIP(p.Dst.Addr())
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if err != nil {
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p.Trace("%v", err)
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return
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}
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if m.PacketHandler == nil {
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// Forwarding not allowed by default
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p.Trace("drop, forwarding not allowed")
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return
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}
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p2 := m.PacketHandler.HandleForward(p.Clone(), iif, oif)
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if p2 == nil {
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p.Trace("drop")
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// Packet dropped, done.
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return
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}
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if !p.Equivalent(p2) {
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// Packet changed, restart delivery.
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p2.Trace("PacketHandler mutated packet")
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m.deliverIncomingPacket(p2, iif)
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return
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}
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p.Trace("-> net=%s oif=%s", oif.net.Name, oif)
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oif.net.write(p)
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}
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// Attach adds an interface to a machine.
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//
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// The first interface added to a Machine becomes that machine's
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// default route.
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func (m *Machine) Attach(interfaceName string, n *Network) *Interface {
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f := &Interface{
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machine: m,
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net: n,
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name: interfaceName,
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}
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if ip := n.allocIPv4(f); ip.IsValid() {
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f.ips = append(f.ips, ip)
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}
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if ip := n.allocIPv6(f); ip.IsValid() {
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f.ips = append(f.ips, ip)
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}
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m.mu.Lock()
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defer m.mu.Unlock()
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m.interfaces = append(m.interfaces, f)
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if len(m.interfaces) == 1 {
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m.routes = append(m.routes,
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routeEntry{
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prefix: mustPrefix("0.0.0.0/0"),
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iface: f,
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},
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routeEntry{
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prefix: mustPrefix("::/0"),
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iface: f,
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})
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} else {
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if n.Prefix4.IsValid() {
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m.routes = append(m.routes, routeEntry{
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prefix: n.Prefix4,
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iface: f,
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})
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}
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if n.Prefix6.IsValid() {
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m.routes = append(m.routes, routeEntry{
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prefix: n.Prefix6,
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iface: f,
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})
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}
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}
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sort.Slice(m.routes, func(i, j int) bool {
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return m.routes[i].prefix.Bits() > m.routes[j].prefix.Bits()
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})
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return f
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}
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var (
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v4unspec = netaddr.IPv4(0, 0, 0, 0)
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v6unspec = netip.IPv6Unspecified()
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)
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func (m *Machine) writePacket(p *Packet) (n int, err error) {
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p.setLocator("mach=%s", m.Name)
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iface, err := m.interfaceForIP(p.Dst.Addr())
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if err != nil {
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p.Trace("%v", err)
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return 0, err
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}
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origSrcIP := p.Src.Addr()
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switch {
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case p.Src.Addr() == v4unspec:
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p.Trace("assigning srcIP=%s", iface.V4())
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p.Src = netip.AddrPortFrom(iface.V4(), p.Src.Port())
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case p.Src.Addr() == v6unspec:
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// v6unspec in Go means "any src, but match address families"
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if p.Dst.Addr().Is6() {
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p.Trace("assigning srcIP=%s", iface.V6())
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p.Src = netip.AddrPortFrom(iface.V6(), p.Src.Port())
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} else if p.Dst.Addr().Is4() {
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p.Trace("assigning srcIP=%s", iface.V4())
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p.Src = netip.AddrPortFrom(iface.V4(), p.Src.Port())
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}
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default:
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if !iface.Contains(p.Src.Addr()) {
|
|
err := fmt.Errorf("can't send to %v with src %v on interface %v", p.Dst.Addr(), p.Src.Addr(), iface)
|
|
p.Trace("%v", err)
|
|
return 0, err
|
|
}
|
|
}
|
|
if !p.Src.Addr().IsValid() {
|
|
err := fmt.Errorf("no matching address for address family for %v", origSrcIP)
|
|
p.Trace("%v", err)
|
|
return 0, err
|
|
}
|
|
|
|
if m.PacketHandler != nil {
|
|
p2 := m.PacketHandler.HandleOut(p.Clone(), iface)
|
|
if p2 == nil {
|
|
// Packet dropped, done.
|
|
return len(p.Payload), nil
|
|
}
|
|
if !p.Equivalent(p2) {
|
|
// Restart transmission, src may have changed weirdly
|
|
m.writePacket(p2)
|
|
return
|
|
}
|
|
}
|
|
|
|
p.Trace("-> net=%s if=%s", iface.net.Name, iface)
|
|
return iface.net.write(p)
|
|
}
|
|
|
|
func (m *Machine) interfaceForIP(ip netip.Addr) (*Interface, error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
for _, re := range m.routes {
|
|
if re.prefix.Contains(ip) {
|
|
return re.iface, nil
|
|
}
|
|
}
|
|
return nil, fmt.Errorf("no route found to %v", ip)
|
|
}
|
|
|
|
func (m *Machine) pickEphemPort() (port uint16, err error) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
for tries := 0; tries < 500; tries++ {
|
|
port := uint16(rand.Intn(32<<10) + 32<<10)
|
|
if !m.portInUseLocked(port) {
|
|
return port, nil
|
|
}
|
|
}
|
|
return 0, errors.New("failed to find an ephemeral port")
|
|
}
|
|
|
|
func (m *Machine) portInUseLocked(port uint16) bool {
|
|
for ipp := range m.conns4 {
|
|
if ipp.Port() == port {
|
|
return true
|
|
}
|
|
}
|
|
for ipp := range m.conns6 {
|
|
if ipp.Port() == port {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (m *Machine) registerConn4(c *conn) error {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
if c.ipp.Addr().Is6() && c.ipp.Addr() != v6unspec {
|
|
return fmt.Errorf("registerConn4 got IPv6 %s", c.ipp)
|
|
}
|
|
return registerConn(&m.conns4, c)
|
|
}
|
|
|
|
func (m *Machine) unregisterConn4(c *conn) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
delete(m.conns4, c.ipp)
|
|
}
|
|
|
|
func (m *Machine) registerConn6(c *conn) error {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
if c.ipp.Addr().Is4() {
|
|
return fmt.Errorf("registerConn6 got IPv4 %s", c.ipp)
|
|
}
|
|
return registerConn(&m.conns6, c)
|
|
}
|
|
|
|
func (m *Machine) unregisterConn6(c *conn) {
|
|
m.mu.Lock()
|
|
defer m.mu.Unlock()
|
|
delete(m.conns6, c.ipp)
|
|
}
|
|
|
|
func registerConn(conns *map[netip.AddrPort]*conn, c *conn) error {
|
|
if _, ok := (*conns)[c.ipp]; ok {
|
|
return fmt.Errorf("duplicate conn listening on %v", c.ipp)
|
|
}
|
|
if *conns == nil {
|
|
*conns = map[netip.AddrPort]*conn{}
|
|
}
|
|
(*conns)[c.ipp] = c
|
|
return nil
|
|
}
|
|
|
|
func (m *Machine) AddNetwork(n *Network) {}
|
|
|
|
func (m *Machine) ListenPacket(ctx context.Context, network, address string) (net.PacketConn, error) {
|
|
// if udp4, udp6, etc... look at address IP vs unspec
|
|
var (
|
|
fam uint8
|
|
ip netip.Addr
|
|
)
|
|
switch network {
|
|
default:
|
|
return nil, fmt.Errorf("unsupported network type %q", network)
|
|
case "udp":
|
|
fam = 0
|
|
ip = v6unspec
|
|
case "udp4":
|
|
fam = 4
|
|
ip = v4unspec
|
|
case "udp6":
|
|
fam = 6
|
|
ip = v6unspec
|
|
}
|
|
|
|
host, portStr, err := net.SplitHostPort(address)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if host != "" {
|
|
ip, err = netip.ParseAddr(host)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if fam == 0 && (ip != v4unspec && ip != v6unspec) {
|
|
// We got an explicit IP address, need to switch the
|
|
// family to the right one.
|
|
if ip.Is4() {
|
|
fam = 4
|
|
} else {
|
|
fam = 6
|
|
}
|
|
}
|
|
}
|
|
porti, err := strconv.ParseUint(portStr, 10, 16)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
port := uint16(porti)
|
|
if port == 0 {
|
|
port, err = m.pickEphemPort()
|
|
if err != nil {
|
|
return nil, nil
|
|
}
|
|
}
|
|
ipp := netip.AddrPortFrom(ip, port)
|
|
|
|
c := &conn{
|
|
m: m,
|
|
fam: fam,
|
|
ipp: ipp,
|
|
in: make(chan *Packet, 100), // arbitrary
|
|
}
|
|
switch c.fam {
|
|
case 0:
|
|
if err := m.registerConn4(c); err != nil {
|
|
return nil, err
|
|
}
|
|
if err := m.registerConn6(c); err != nil {
|
|
m.unregisterConn4(c)
|
|
return nil, err
|
|
}
|
|
case 4:
|
|
if err := m.registerConn4(c); err != nil {
|
|
return nil, err
|
|
}
|
|
case 6:
|
|
if err := m.registerConn6(c); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
return c, nil
|
|
}
|
|
|
|
// conn is our net.PacketConn implementation
|
|
type conn struct {
|
|
m *Machine
|
|
fam uint8 // 0, 4, or 6
|
|
ipp netip.AddrPort
|
|
|
|
mu sync.Mutex
|
|
closed bool
|
|
readDeadline time.Time
|
|
activeReads map[*activeRead]bool
|
|
in chan *Packet
|
|
}
|
|
|
|
type activeRead struct {
|
|
cancel context.CancelFunc
|
|
}
|
|
|
|
// canRead reports whether we can do a read.
|
|
func (c *conn) canRead() error {
|
|
c.mu.Lock()
|
|
defer c.mu.Unlock()
|
|
if c.closed {
|
|
return net.ErrClosed
|
|
}
|
|
if !c.readDeadline.IsZero() && c.readDeadline.Before(time.Now()) {
|
|
return errors.New("read deadline exceeded")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (c *conn) registerActiveRead(ar *activeRead, active bool) {
|
|
c.mu.Lock()
|
|
defer c.mu.Unlock()
|
|
if c.activeReads == nil {
|
|
c.activeReads = make(map[*activeRead]bool)
|
|
}
|
|
if active {
|
|
c.activeReads[ar] = true
|
|
} else {
|
|
delete(c.activeReads, ar)
|
|
}
|
|
}
|
|
|
|
func (c *conn) Close() error {
|
|
c.mu.Lock()
|
|
defer c.mu.Unlock()
|
|
if c.closed {
|
|
return nil
|
|
}
|
|
c.closed = true
|
|
switch c.fam {
|
|
case 0:
|
|
c.m.unregisterConn4(c)
|
|
c.m.unregisterConn6(c)
|
|
case 4:
|
|
c.m.unregisterConn4(c)
|
|
case 6:
|
|
c.m.unregisterConn6(c)
|
|
}
|
|
c.breakActiveReadsLocked()
|
|
return nil
|
|
}
|
|
|
|
func (c *conn) breakActiveReadsLocked() {
|
|
for ar := range c.activeReads {
|
|
ar.cancel()
|
|
}
|
|
c.activeReads = nil
|
|
}
|
|
|
|
func (c *conn) LocalAddr() net.Addr {
|
|
return &net.UDPAddr{
|
|
IP: c.ipp.Addr().AsSlice(),
|
|
Port: int(c.ipp.Port()),
|
|
Zone: c.ipp.Addr().Zone(),
|
|
}
|
|
}
|
|
|
|
func (c *conn) Read(buf []byte) (int, error) {
|
|
panic("unimplemented stub")
|
|
}
|
|
|
|
func (c *conn) RemoteAddr() net.Addr {
|
|
panic("unimplemented stub")
|
|
}
|
|
|
|
func (c *conn) Write(buf []byte) (int, error) {
|
|
panic("unimplemented stub")
|
|
}
|
|
|
|
func (c *conn) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
|
|
n, ap, err := c.ReadFromUDPAddrPort(p)
|
|
if err != nil {
|
|
return 0, nil, err
|
|
}
|
|
return n, net.UDPAddrFromAddrPort(ap), nil
|
|
}
|
|
|
|
func (c *conn) ReadFromUDPAddrPort(p []byte) (n int, addr netip.AddrPort, err error) {
|
|
ctx, cancel := context.WithCancel(context.Background())
|
|
defer cancel()
|
|
|
|
ar := &activeRead{cancel: cancel}
|
|
|
|
if err := c.canRead(); err != nil {
|
|
return 0, netip.AddrPort{}, err
|
|
}
|
|
|
|
c.registerActiveRead(ar, true)
|
|
defer c.registerActiveRead(ar, false)
|
|
|
|
select {
|
|
case pkt := <-c.in:
|
|
n = copy(p, pkt.Payload)
|
|
pkt.Trace("PacketConn.ReadFrom")
|
|
return n, pkt.Src, nil
|
|
case <-ctx.Done():
|
|
return 0, netip.AddrPort{}, context.DeadlineExceeded
|
|
}
|
|
}
|
|
|
|
func (c *conn) WriteTo(p []byte, addr net.Addr) (n int, err error) {
|
|
ipp, err := netip.ParseAddrPort(addr.String())
|
|
if err != nil {
|
|
return 0, fmt.Errorf("bogus addr %T %q", addr, addr.String())
|
|
}
|
|
return c.WriteToUDPAddrPort(p, ipp)
|
|
}
|
|
|
|
func (c *conn) WriteToUDPAddrPort(p []byte, ipp netip.AddrPort) (n int, err error) {
|
|
pkt := &Packet{
|
|
Src: c.ipp,
|
|
Dst: ipp,
|
|
Payload: bytes.Clone(p),
|
|
}
|
|
pkt.setLocator("mach=%s", c.m.Name)
|
|
pkt.Trace("PacketConn.WriteTo")
|
|
return c.m.writePacket(pkt)
|
|
}
|
|
|
|
func (c *conn) SetDeadline(t time.Time) error {
|
|
panic("SetWriteDeadline unsupported; TODO when needed")
|
|
}
|
|
func (c *conn) SetWriteDeadline(t time.Time) error {
|
|
panic("SetWriteDeadline unsupported; TODO when needed")
|
|
}
|
|
func (c *conn) SetReadDeadline(t time.Time) error {
|
|
c.mu.Lock()
|
|
defer c.mu.Unlock()
|
|
|
|
now := time.Now()
|
|
if t.After(now) {
|
|
panic("SetReadDeadline in the future not yet supported; TODO?")
|
|
}
|
|
|
|
if !t.IsZero() && t.Before(now) {
|
|
c.breakActiveReadsLocked()
|
|
}
|
|
c.readDeadline = t
|
|
|
|
return nil
|
|
}
|