Editando: ipsock_plan9.go
// Copyright 2009 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package net import ( "context" "internal/bytealg" "internal/itoa" "io/fs" "os" "syscall" ) // probe probes IPv4, IPv6 and IPv4-mapped IPv6 communication // capabilities. // // Plan 9 uses IPv6 natively, see ip(3). func (p *ipStackCapabilities) probe() { p.ipv4Enabled = probe(netdir+"/iproute", "4i") p.ipv6Enabled = probe(netdir+"/iproute", "6i") if p.ipv4Enabled && p.ipv6Enabled { p.ipv4MappedIPv6Enabled = true } } func probe(filename, query string) bool { var file *file var err error if file, err = open(filename); err != nil { return false } defer file.close() r := false for line, ok := file.readLine(); ok && !r; line, ok = file.readLine() { f := getFields(line) if len(f) < 3 { continue } for i := 0; i < len(f); i++ { if query == f[i] { r = true break } } } return r } // parsePlan9Addr parses address of the form [ip!]port (e.g. 127.0.0.1!80). func parsePlan9Addr(s string) (ip IP, iport int, err error) { addr := IPv4zero // address contains port only i := bytealg.IndexByteString(s, '!') if i >= 0 { addr = ParseIP(s[:i]) if addr == nil { return nil, 0, &ParseError{Type: "IP address", Text: s} } } p, plen, ok := dtoi(s[i+1:]) if !ok { return nil, 0, &ParseError{Type: "port", Text: s} } if p < 0 || p > 0xFFFF { return nil, 0, &AddrError{Err: "invalid port", Addr: s[i+1 : i+1+plen]} } return addr, p, nil } func readPlan9Addr(net, filename string) (addr Addr, err error) { var buf [128]byte f, err := os.Open(filename) if err != nil { return } defer f.Close() n, err := f.Read(buf[:]) if err != nil { return } ip, port, err := parsePlan9Addr(string(buf[:n])) if err != nil { return } switch net { case "tcp4", "udp4": if ip.Equal(IPv6zero) { ip = ip[:IPv4len] } } switch net { case "tcp", "tcp4", "tcp6": addr = &TCPAddr{IP: ip, Port: port} case "udp", "udp4", "udp6": addr = &UDPAddr{IP: ip, Port: port} default: return nil, UnknownNetworkError(net) } return addr, nil } func startPlan9(ctx context.Context, net string, addr Addr) (ctl *os.File, dest, proto, name string, err error) { var ( ip IP port int ) switch a := addr.(type) { case *TCPAddr: proto = "tcp" ip = a.IP port = a.Port case *UDPAddr: proto = "udp" ip = a.IP port = a.Port default: err = UnknownNetworkError(net) return } if port > 65535 { err = InvalidAddrError("port should be < 65536") return } clone, dest, err := queryCS1(ctx, proto, ip, port) if err != nil { return } f, err := os.OpenFile(clone, os.O_RDWR, 0) if err != nil { return } var buf [16]byte n, err := f.Read(buf[:]) if err != nil { f.Close() return } return f, dest, proto, string(buf[:n]), nil } func fixErr(err error) { oe, ok := err.(*OpError) if !ok { return } nonNilInterface := func(a Addr) bool { switch a := a.(type) { case *TCPAddr: return a == nil case *UDPAddr: return a == nil case *IPAddr: return a == nil default: return false } } if nonNilInterface(oe.Source) { oe.Source = nil } if nonNilInterface(oe.Addr) { oe.Addr = nil } if pe, ok := oe.Err.(*fs.PathError); ok { if _, ok = pe.Err.(syscall.ErrorString); ok { oe.Err = pe.Err } } } func dialPlan9(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) { defer func() { fixErr(err) }() type res struct { fd *netFD err error } resc := make(chan res) go func() { fd, err := dialPlan9Blocking(ctx, net, laddr, raddr) select { case resc <- res{fd, err}: case <-ctx.Done(): if fd != nil { fd.Close() } } }() select { case res := <-resc: return res.fd, res.err case <-ctx.Done(): return nil, mapErr(ctx.Err()) } } func dialPlan9Blocking(ctx context.Context, net string, laddr, raddr Addr) (fd *netFD, err error) { if isWildcard(raddr) { raddr = toLocal(raddr, net) } f, dest, proto, name, err := startPlan9(ctx, net, raddr) if err != nil { return nil, err } if la := plan9LocalAddr(laddr); la == "" { err = hangupCtlWrite(ctx, proto, f, "connect "+dest) } else { err = hangupCtlWrite(ctx, proto, f, "connect "+dest+" "+la) } if err != nil { f.Close() return nil, err } data, err := os.OpenFile(netdir+"/"+proto+"/"+name+"/data", os.O_RDWR, 0) if err != nil { f.Close() return nil, err } laddr, err = readPlan9Addr(net, netdir+"/"+proto+"/"+name+"/local") if err != nil { data.Close() f.Close() return nil, err } return newFD(proto, name, nil, f, data, laddr, raddr) } func listenPlan9(ctx context.Context, net string, laddr Addr) (fd *netFD, err error) { defer func() { fixErr(err) }() f, dest, proto, name, err := startPlan9(ctx, net, laddr) if err != nil { return nil, err } _, err = f.WriteString("announce " + dest) if err != nil { f.Close() return nil, &OpError{Op: "announce", Net: net, Source: laddr, Addr: nil, Err: err} } laddr, err = readPlan9Addr(net, netdir+"/"+proto+"/"+name+"/local") if err != nil { f.Close() return nil, err } return newFD(proto, name, nil, f, nil, laddr, nil) } func (fd *netFD) netFD() (*netFD, error) { return newFD(fd.net, fd.n, fd.listen, fd.ctl, fd.data, fd.laddr, fd.raddr) } func (fd *netFD) acceptPlan9() (nfd *netFD, err error) { defer func() { fixErr(err) }() if err := fd.pfd.ReadLock(); err != nil { return nil, err } defer fd.pfd.ReadUnlock() listen, err := os.Open(fd.dir + "/listen") if err != nil { return nil, err } var buf [16]byte n, err := listen.Read(buf[:]) if err != nil { listen.Close() return nil, err } name := string(buf[:n]) ctl, err := os.OpenFile(netdir+"/"+fd.net+"/"+name+"/ctl", os.O_RDWR, 0) if err != nil { listen.Close() return nil, err } data, err := os.OpenFile(netdir+"/"+fd.net+"/"+name+"/data", os.O_RDWR, 0) if err != nil { listen.Close() ctl.Close() return nil, err } raddr, err := readPlan9Addr(fd.net, netdir+"/"+fd.net+"/"+name+"/remote") if err != nil { listen.Close() ctl.Close() data.Close() return nil, err } return newFD(fd.net, name, listen, ctl, data, fd.laddr, raddr) } func isWildcard(a Addr) bool { var wildcard bool switch a := a.(type) { case *TCPAddr: wildcard = a.isWildcard() case *UDPAddr: wildcard = a.isWildcard() case *IPAddr: wildcard = a.isWildcard() } return wildcard } func toLocal(a Addr, net string) Addr { switch a := a.(type) { case *TCPAddr: a.IP = loopbackIP(net) case *UDPAddr: a.IP = loopbackIP(net) case *IPAddr: a.IP = loopbackIP(net) } return a } // plan9LocalAddr returns a Plan 9 local address string. // See setladdrport at https://9p.io/sources/plan9/sys/src/9/ip/devip.c. func plan9LocalAddr(addr Addr) string { var ip IP port := 0 switch a := addr.(type) { case *TCPAddr: if a != nil { ip = a.IP port = a.Port } case *UDPAddr: if a != nil { ip = a.IP port = a.Port } } if len(ip) == 0 || ip.IsUnspecified() { if port == 0 { return "" } return itoa.Itoa(port) } return ip.String() + "!" + itoa.Itoa(port) } func hangupCtlWrite(ctx context.Context, proto string, ctl *os.File, msg string) error { if proto != "tcp" { _, err := ctl.WriteString(msg) return err } written := make(chan struct{}) errc := make(chan error) go func() { select { case <-ctx.Done(): ctl.WriteString("hangup") errc <- mapErr(ctx.Err()) case <-written: errc <- nil } }() _, err := ctl.WriteString(msg) close(written) if e := <-errc; err == nil && e != nil { // we hung up return e } return err }
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