Preview: ipsock_plan9.go
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/proc/thread-self/root/opt/golang/1.22.0/src/net/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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