mirror of
https://github.com/autc04/Retro68.git
synced 2024-08-31 09:29:37 +00:00
368 lines
7.5 KiB
Go
368 lines
7.5 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package net
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import (
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"context"
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"internal/bytealg"
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"internal/itoa"
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"io/fs"
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"os"
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"syscall"
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)
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// probe probes IPv4, IPv6 and IPv4-mapped IPv6 communication
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// capabilities.
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//
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// Plan 9 uses IPv6 natively, see ip(3).
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func (p *ipStackCapabilities) probe() {
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p.ipv4Enabled = probe(netdir+"/iproute", "4i")
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p.ipv6Enabled = probe(netdir+"/iproute", "6i")
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if p.ipv4Enabled && p.ipv6Enabled {
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p.ipv4MappedIPv6Enabled = true
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}
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}
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func probe(filename, query string) bool {
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var file *file
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var err error
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if file, err = open(filename); err != nil {
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return false
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}
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defer file.close()
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r := false
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for line, ok := file.readLine(); ok && !r; line, ok = file.readLine() {
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f := getFields(line)
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if len(f) < 3 {
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continue
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}
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for i := 0; i < len(f); i++ {
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if query == f[i] {
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r = true
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break
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}
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}
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}
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return r
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}
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// parsePlan9Addr parses address of the form [ip!]port (e.g. 127.0.0.1!80).
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func parsePlan9Addr(s string) (ip IP, iport int, err error) {
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addr := IPv4zero // address contains port only
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i := bytealg.IndexByteString(s, '!')
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if i >= 0 {
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addr = ParseIP(s[:i])
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if addr == nil {
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return nil, 0, &ParseError{Type: "IP address", Text: s}
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}
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}
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p, plen, ok := dtoi(s[i+1:])
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if !ok {
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return nil, 0, &ParseError{Type: "port", Text: s}
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}
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if p < 0 || p > 0xFFFF {
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return nil, 0, &AddrError{Err: "invalid port", Addr: s[i+1 : i+1+plen]}
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}
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return addr, p, nil
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}
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func readPlan9Addr(net, filename string) (addr Addr, err error) {
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var buf [128]byte
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f, err := os.Open(filename)
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if err != nil {
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return
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}
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defer f.Close()
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n, err := f.Read(buf[:])
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if err != nil {
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return
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}
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ip, port, err := parsePlan9Addr(string(buf[:n]))
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if err != nil {
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return
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}
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switch net {
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case "tcp4", "udp4":
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if ip.Equal(IPv6zero) {
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ip = ip[:IPv4len]
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}
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}
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switch net {
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case "tcp", "tcp4", "tcp6":
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addr = &TCPAddr{IP: ip, Port: port}
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case "udp", "udp4", "udp6":
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addr = &UDPAddr{IP: ip, Port: port}
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default:
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return nil, UnknownNetworkError(net)
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}
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return addr, nil
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}
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func startPlan9(ctx context.Context, net string, addr Addr) (ctl *os.File, dest, proto, name string, err error) {
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var (
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ip IP
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port int
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)
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switch a := addr.(type) {
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case *TCPAddr:
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proto = "tcp"
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ip = a.IP
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port = a.Port
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case *UDPAddr:
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proto = "udp"
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ip = a.IP
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port = a.Port
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default:
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err = UnknownNetworkError(net)
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return
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}
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if port > 65535 {
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err = InvalidAddrError("port should be < 65536")
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return
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}
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clone, dest, err := queryCS1(ctx, proto, ip, port)
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if err != nil {
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return
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}
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f, err := os.OpenFile(clone, os.O_RDWR, 0)
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if err != nil {
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return
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}
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var buf [16]byte
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n, err := f.Read(buf[:])
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if err != nil {
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f.Close()
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return
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}
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return f, dest, proto, string(buf[:n]), nil
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}
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func fixErr(err error) {
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oe, ok := err.(*OpError)
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if !ok {
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return
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}
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nonNilInterface := func(a Addr) bool {
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switch a := a.(type) {
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case *TCPAddr:
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return a == nil
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case *UDPAddr:
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return a == nil
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case *IPAddr:
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return a == nil
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default:
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return false
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}
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}
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if nonNilInterface(oe.Source) {
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oe.Source = nil
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}
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if nonNilInterface(oe.Addr) {
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oe.Addr = nil
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}
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if pe, ok := oe.Err.(*fs.PathError); ok {
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if _, ok = pe.Err.(syscall.ErrorString); ok {
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oe.Err = pe.Err
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}
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}
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}
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func dialPlan9(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) {
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defer func() { fixErr(err) }()
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type res struct {
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fd *netFD
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err error
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}
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resc := make(chan res)
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go func() {
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testHookDialChannel()
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fd, err := dialPlan9Blocking(ctx, net, laddr, raddr)
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select {
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case resc <- res{fd, err}:
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case <-ctx.Done():
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if fd != nil {
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fd.Close()
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}
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}
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}()
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select {
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case res := <-resc:
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return res.fd, res.err
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case <-ctx.Done():
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return nil, mapErr(ctx.Err())
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}
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}
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func dialPlan9Blocking(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) {
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if isWildcard(raddr) {
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raddr = toLocal(raddr, net)
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}
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f, dest, proto, name, err := startPlan9(ctx, net, raddr)
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if err != nil {
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return nil, err
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}
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if la := plan9LocalAddr(laddr); la == "" {
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err = hangupCtlWrite(ctx, proto, f, "connect "+dest)
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} else {
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err = hangupCtlWrite(ctx, proto, f, "connect "+dest+" "+la)
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}
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if err != nil {
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f.Close()
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return nil, err
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}
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data, err := os.OpenFile(netdir+"/"+proto+"/"+name+"/data", os.O_RDWR, 0)
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if err != nil {
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f.Close()
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return nil, err
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}
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laddr, err = readPlan9Addr(net, netdir+"/"+proto+"/"+name+"/local")
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if err != nil {
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data.Close()
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f.Close()
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return nil, err
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}
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return newFD(proto, name, nil, f, data, laddr, raddr)
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}
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func listenPlan9(ctx context.Context, net string, laddr Addr) (fd *netFD, err error) {
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defer func() { fixErr(err) }()
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f, dest, proto, name, err := startPlan9(ctx, net, laddr)
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if err != nil {
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return nil, err
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}
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_, err = f.WriteString("announce " + dest)
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if err != nil {
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f.Close()
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return nil, &OpError{Op: "announce", Net: net, Source: laddr, Addr: nil, Err: err}
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}
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laddr, err = readPlan9Addr(net, netdir+"/"+proto+"/"+name+"/local")
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if err != nil {
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f.Close()
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return nil, err
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}
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return newFD(proto, name, nil, f, nil, laddr, nil)
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}
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func (fd *netFD) netFD() (*netFD, error) {
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return newFD(fd.net, fd.n, fd.listen, fd.ctl, fd.data, fd.laddr, fd.raddr)
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}
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func (fd *netFD) acceptPlan9() (nfd *netFD, err error) {
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defer func() { fixErr(err) }()
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if err := fd.pfd.ReadLock(); err != nil {
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return nil, err
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}
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defer fd.pfd.ReadUnlock()
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listen, err := os.Open(fd.dir + "/listen")
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if err != nil {
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return nil, err
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}
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var buf [16]byte
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n, err := listen.Read(buf[:])
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if err != nil {
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listen.Close()
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return nil, err
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}
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name := string(buf[:n])
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ctl, err := os.OpenFile(netdir+"/"+fd.net+"/"+name+"/ctl", os.O_RDWR, 0)
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if err != nil {
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listen.Close()
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return nil, err
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}
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data, err := os.OpenFile(netdir+"/"+fd.net+"/"+name+"/data", os.O_RDWR, 0)
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if err != nil {
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listen.Close()
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ctl.Close()
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return nil, err
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}
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raddr, err := readPlan9Addr(fd.net, netdir+"/"+fd.net+"/"+name+"/remote")
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if err != nil {
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listen.Close()
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ctl.Close()
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data.Close()
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return nil, err
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}
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return newFD(fd.net, name, listen, ctl, data, fd.laddr, raddr)
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}
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func isWildcard(a Addr) bool {
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var wildcard bool
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switch a := a.(type) {
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case *TCPAddr:
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wildcard = a.isWildcard()
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case *UDPAddr:
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wildcard = a.isWildcard()
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case *IPAddr:
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wildcard = a.isWildcard()
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}
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return wildcard
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}
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func toLocal(a Addr, net string) Addr {
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switch a := a.(type) {
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case *TCPAddr:
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a.IP = loopbackIP(net)
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case *UDPAddr:
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a.IP = loopbackIP(net)
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case *IPAddr:
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a.IP = loopbackIP(net)
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}
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return a
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}
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// plan9LocalAddr returns a Plan 9 local address string.
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// See setladdrport at https://9p.io/sources/plan9/sys/src/9/ip/devip.c.
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func plan9LocalAddr(addr Addr) string {
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var ip IP
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port := 0
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switch a := addr.(type) {
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case *TCPAddr:
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if a != nil {
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ip = a.IP
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port = a.Port
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}
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case *UDPAddr:
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if a != nil {
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ip = a.IP
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port = a.Port
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}
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}
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if len(ip) == 0 || ip.IsUnspecified() {
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if port == 0 {
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return ""
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}
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return itoa.Itoa(port)
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}
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return ip.String() + "!" + itoa.Itoa(port)
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}
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func hangupCtlWrite(ctx context.Context, proto string, ctl *os.File, msg string) error {
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if proto != "tcp" {
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_, err := ctl.WriteString(msg)
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return err
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}
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written := make(chan struct{})
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errc := make(chan error)
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go func() {
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select {
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case <-ctx.Done():
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ctl.WriteString("hangup")
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errc <- mapErr(ctx.Err())
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case <-written:
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errc <- nil
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}
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}()
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_, err := ctl.WriteString(msg)
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close(written)
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if e := <-errc; err == nil && e != nil { // we hung up
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return e
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}
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return err
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}
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