src/pkg/net/ipsock.go - go - Git at Google

 // 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.

 // IP sockets

 package net

 import (
 	"os"
 	"syscall"
 )

 // Should we try to use the IPv4 socket interface if we're
 // only dealing with IPv4 sockets?  As long as the host system
 // understands IPv6, it's okay to pass IPv4 addresses to the IPv6
 // interface.  That simplifies our code and is most general.
 // Unfortunately, we need to run on kernels built without IPv6 support too.
 // So probe the kernel to figure it out.
 func kernelSupportsIPv6() bool {
 	s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
 	if err != 0 {
 		return false
 	}
 	defer closesocket(s)

 	la := &TCPAddr{IP: IPv4(127, 0, 0, 1)}
 	sa, oserr := la.toAddr().sockaddr(syscall.AF_INET6)
 	if oserr != nil {
 		return false
 	}

 	return syscall.Bind(s, sa) == 0
 }

 var preferIPv4 = !kernelSupportsIPv6()

 func firstSupportedAddr(addrs []string) (addr IP) {
 	for _, s := range addrs {
 		addr = ParseIP(s)
 		if !preferIPv4 || addr.To4() != nil {
 			break
 		}
 		addr = nil
 	}
 	return addr
 }

 // TODO(rsc): if syscall.OS == "linux", we're supposd to read
 // /proc/sys/net/core/somaxconn,
 // to take advantage of kernels that have raised the limit.
 func listenBacklog() int { return syscall.SOMAXCONN }

 // Internet sockets (TCP, UDP)

 // A sockaddr represents a TCP or UDP network address that can
 // be converted into a syscall.Sockaddr.
 type sockaddr interface {
 	Addr
 	sockaddr(family int) (syscall.Sockaddr, os.Error)
 	family() int
 }

 func internetSocket(net string, laddr, raddr sockaddr, socktype, proto int, mode string, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err os.Error) {
 	// Figure out IP version.
 	// If network has a suffix like "tcp4", obey it.
 	var oserr os.Error
 	family := syscall.AF_INET6
 	switch net[len(net)-1] {
 	case '4':
 		family = syscall.AF_INET
 	case '6':
 		// nothing to do
 	default:
 		// Otherwise, guess.
 		// If the addresses are IPv4 and we prefer IPv4, use 4; else 6.
 		if preferIPv4 &&
 			(laddr == nil || laddr.family() == syscall.AF_INET) &&
 			(raddr == nil || raddr.family() == syscall.AF_INET) {
 			family = syscall.AF_INET
 		}
 	}

 	var la, ra syscall.Sockaddr
 	if laddr != nil {
 		if la, oserr = laddr.sockaddr(family); oserr != nil {
 			goto Error
 		}
 	}
 	if raddr != nil {
 		if ra, oserr = raddr.sockaddr(family); oserr != nil {
 			goto Error
 		}
 	}
 	fd, oserr = socket(net, family, socktype, proto, la, ra, toAddr)
 	if oserr != nil {
 		goto Error
 	}
 	return fd, nil

 Error:
 	addr := raddr
 	if mode == "listen" {
 		addr = laddr
 	}
 	return nil, &OpError{mode, net, addr, oserr}
 }

 func getip(fd int, remote bool) (ip []byte, port int, ok bool) {
 	// No attempt at error reporting because
 	// there are no possible errors, and the
 	// caller won't report them anyway.
 	var sa syscall.Sockaddr
 	if remote {
 		sa, _ = syscall.Getpeername(fd)
 	} else {
 		sa, _ = syscall.Getsockname(fd)
 	}
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
 		return sa.Addr[0:], sa.Port, true
 	case *syscall.SockaddrInet6:
 		return sa.Addr[0:], sa.Port, true
 	}
 	return
 }

 type InvalidAddrError string

 func (e InvalidAddrError) String() string  { return string(e) }
 func (e InvalidAddrError) Timeout() bool   { return false }
 func (e InvalidAddrError) Temporary() bool { return false }


 func ipToSockaddr(family int, ip IP, port int) (syscall.Sockaddr, os.Error) {
 	switch family {
 	case syscall.AF_INET:
 		if len(ip) == 0 {
 			ip = IPv4zero
 		}
 		if ip = ip.To4(); ip == nil {
 			return nil, InvalidAddrError("non-IPv4 address")
 		}
 		s := new(syscall.SockaddrInet4)
 		for i := 0; i < IPv4len; i++ {
 			s.Addr[i] = ip[i]
 		}
 		s.Port = port
 		return s, nil
 	case syscall.AF_INET6:
 		if len(ip) == 0 {
 			ip = IPzero
 		}
 		// IPv4 callers use 0.0.0.0 to mean "announce on any available address".
 		// In IPv6 mode, Linux treats that as meaning "announce on 0.0.0.0",
 		// which it refuses to do.  Rewrite to the IPv6 all zeros.
 		if p4 := ip.To4(); p4 != nil && p4[0] == 0 && p4[1] == 0 && p4[2] == 0 && p4[3] == 0 {
 			ip = IPzero
 		}
 		if ip = ip.To16(); ip == nil {
 			return nil, InvalidAddrError("non-IPv6 address")
 		}
 		s := new(syscall.SockaddrInet6)
 		for i := 0; i < IPv6len; i++ {
 			s.Addr[i] = ip[i]
 		}
 		s.Port = port
 		return s, nil
 	}
 	return nil, InvalidAddrError("unexpected socket family")
 }

 // Split "host:port" into "host" and "port".
 // Host cannot contain colons unless it is bracketed.
 func splitHostPort(hostport string) (host, port string, err os.Error) {
 	// The port starts after the last colon.
 	i := last(hostport, ':')
 	if i < 0 {
 		err = &AddrError{"missing port in address", hostport}
 		return
 	}

 	host, port = hostport[0:i], hostport[i+1:]

 	// Can put brackets around host ...
 	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
 		host = host[1 : len(host)-1]
 	} else {
 		// ... but if there are no brackets, no colons.
 		if byteIndex(host, ':') >= 0 {
 			err = &AddrError{"too many colons in address", hostport}
 			return
 		}
 	}
 	return
 }

 // Join "host" and "port" into "host:port".
 // If host contains colons, will join into "[host]:port".
 func joinHostPort(host, port string) string {
 	// If host has colons, have to bracket it.
 	if byteIndex(host, ':') >= 0 {
 		return "[" + host + "]:" + port
 	}
 	return host + ":" + port
 }

 // Convert "host:port" into IP address and port.
 func hostPortToIP(net, hostport string) (ip IP, iport int, err os.Error) {
 	host, port, err := splitHostPort(hostport)
 	if err != nil {
 		goto Error
 	}

 	var addr IP
 	if host != "" {
 		// Try as an IP address.
 		addr = ParseIP(host)
 		if addr == nil {
 			// Not an IP address.  Try as a DNS name.
 			_, addrs, err1 := LookupHost(host)
 			if err1 != nil {
 				err = err1
 				goto Error
 			}
 			addr = firstSupportedAddr(addrs)
 			if addr == nil {
 				// should not happen
 				err = &AddrError{"LookupHost returned invalid address", addrs[0]}
 				goto Error
 			}
 		}
 	}

 	p, i, ok := dtoi(port, 0)
 	if !ok || i != len(port) {
 		p, err = LookupPort(net, port)
 		if err != nil {
 			goto Error
 		}
 	}
 	if p < 0 || p > 0xFFFF {
 		err = &AddrError{"invalid port", port}
 		goto Error
 	}

 	return addr, p, nil

 Error:
 	return nil, 0, err
 }
	// 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.

	// IP sockets

	package net

	import (
	"os"
	"syscall"
	)

	// Should we try to use the IPv4 socket interface if we're
	// only dealing with IPv4 sockets? As long as the host system
	// understands IPv6, it's okay to pass IPv4 addresses to the IPv6
	// interface. That simplifies our code and is most general.
	// Unfortunately, we need to run on kernels built without IPv6 support too.
	// So probe the kernel to figure it out.
	func kernelSupportsIPv6() bool {
	s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
	if err != 0 {
	return false
	}
	defer closesocket(s)

	la := &TCPAddr{IP: IPv4(127, 0, 0, 1)}
	sa, oserr := la.toAddr().sockaddr(syscall.AF_INET6)
	if oserr != nil {
	return false
	}

	return syscall.Bind(s, sa) == 0
	}

	var preferIPv4 = !kernelSupportsIPv6()

	func firstSupportedAddr(addrs []string) (addr IP) {
	for _, s := range addrs {
	addr = ParseIP(s)
	if !preferIPv4 \|\| addr.To4() != nil {
	break
	}
	addr = nil
	}
	return addr
	}

	// TODO(rsc): if syscall.OS == "linux", we're supposd to read
	// /proc/sys/net/core/somaxconn,
	// to take advantage of kernels that have raised the limit.
	func listenBacklog() int { return syscall.SOMAXCONN }

	// Internet sockets (TCP, UDP)

	// A sockaddr represents a TCP or UDP network address that can
	// be converted into a syscall.Sockaddr.
	type sockaddr interface {
	Addr
	sockaddr(family int) (syscall.Sockaddr, os.Error)
	family() int
	}

	func internetSocket(net string, laddr, raddr sockaddr, socktype, proto int, mode string, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err os.Error) {
	// Figure out IP version.
	// If network has a suffix like "tcp4", obey it.
	var oserr os.Error
	family := syscall.AF_INET6
	switch net[len(net)-1] {
	case '4':
	family = syscall.AF_INET
	case '6':
	// nothing to do
	default:
	// Otherwise, guess.
	// If the addresses are IPv4 and we prefer IPv4, use 4; else 6.
	if preferIPv4 &&
	(laddr == nil \|\| laddr.family() == syscall.AF_INET) &&
	(raddr == nil \|\| raddr.family() == syscall.AF_INET) {
	family = syscall.AF_INET
	}
	}

	var la, ra syscall.Sockaddr
	if laddr != nil {
	if la, oserr = laddr.sockaddr(family); oserr != nil {
	goto Error
	}
	}
	if raddr != nil {
	if ra, oserr = raddr.sockaddr(family); oserr != nil {
	goto Error
	}
	}
	fd, oserr = socket(net, family, socktype, proto, la, ra, toAddr)
	if oserr != nil {
	goto Error
	}
	return fd, nil

	Error:
	addr := raddr
	if mode == "listen" {
	addr = laddr
	}
	return nil, &OpError{mode, net, addr, oserr}
	}

	func getip(fd int, remote bool) (ip []byte, port int, ok bool) {
	// No attempt at error reporting because
	// there are no possible errors, and the
	// caller won't report them anyway.
	var sa syscall.Sockaddr
	if remote {
	sa, _ = syscall.Getpeername(fd)
	} else {
	sa, _ = syscall.Getsockname(fd)
	}
	switch sa := sa.(type) {
	case *syscall.SockaddrInet4:
	return sa.Addr[0:], sa.Port, true
	case *syscall.SockaddrInet6:
	return sa.Addr[0:], sa.Port, true
	}
	return
	}

	type InvalidAddrError string

	func (e InvalidAddrError) String() string { return string(e) }
	func (e InvalidAddrError) Timeout() bool { return false }
	func (e InvalidAddrError) Temporary() bool { return false }


	func ipToSockaddr(family int, ip IP, port int) (syscall.Sockaddr, os.Error) {
	switch family {
	case syscall.AF_INET:
	if len(ip) == 0 {
	ip = IPv4zero
	}
	if ip = ip.To4(); ip == nil {
	return nil, InvalidAddrError("non-IPv4 address")
	}
	s := new(syscall.SockaddrInet4)
	for i := 0; i < IPv4len; i++ {
	s.Addr[i] = ip[i]
	}
	s.Port = port
	return s, nil
	case syscall.AF_INET6:
	if len(ip) == 0 {
	ip = IPzero
	}
	// IPv4 callers use 0.0.0.0 to mean "announce on any available address".
	// In IPv6 mode, Linux treats that as meaning "announce on 0.0.0.0",
	// which it refuses to do. Rewrite to the IPv6 all zeros.
	if p4 := ip.To4(); p4 != nil && p4[0] == 0 && p4[1] == 0 && p4[2] == 0 && p4[3] == 0 {
	ip = IPzero
	}
	if ip = ip.To16(); ip == nil {
	return nil, InvalidAddrError("non-IPv6 address")
	}
	s := new(syscall.SockaddrInet6)
	for i := 0; i < IPv6len; i++ {
	s.Addr[i] = ip[i]
	}
	s.Port = port
	return s, nil
	}
	return nil, InvalidAddrError("unexpected socket family")
	}

	// Split "host:port" into "host" and "port".
	// Host cannot contain colons unless it is bracketed.
	func splitHostPort(hostport string) (host, port string, err os.Error) {
	// The port starts after the last colon.
	i := last(hostport, ':')
	if i < 0 {
	err = &AddrError{"missing port in address", hostport}
	return
	}

	host, port = hostport[0:i], hostport[i+1:]

	// Can put brackets around host ...
	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
	host = host[1 : len(host)-1]
	} else {
	// ... but if there are no brackets, no colons.
	if byteIndex(host, ':') >= 0 {
	err = &AddrError{"too many colons in address", hostport}
	return
	}
	}
	return
	}

	// Join "host" and "port" into "host:port".
	// If host contains colons, will join into "[host]:port".
	func joinHostPort(host, port string) string {
	// If host has colons, have to bracket it.
	if byteIndex(host, ':') >= 0 {
	return "[" + host + "]:" + port
	}
	return host + ":" + port
	}

	// Convert "host:port" into IP address and port.
	func hostPortToIP(net, hostport string) (ip IP, iport int, err os.Error) {
	host, port, err := splitHostPort(hostport)
	if err != nil {
	goto Error
	}

	var addr IP
	if host != "" {
	// Try as an IP address.
	addr = ParseIP(host)
	if addr == nil {
	// Not an IP address. Try as a DNS name.
	_, addrs, err1 := LookupHost(host)
	if err1 != nil {
	err = err1
	goto Error
	}
	addr = firstSupportedAddr(addrs)
	if addr == nil {
	// should not happen
	err = &AddrError{"LookupHost returned invalid address", addrs[0]}
	goto Error
	}
	}
	}

	p, i, ok := dtoi(port, 0)
	if !ok \|\| i != len(port) {
	p, err = LookupPort(net, port)
	if err != nil {
	goto Error
	}
	}
	if p < 0 \|\| p > 0xFFFF {
	err = &AddrError{"invalid port", port}
	goto Error
	}

	return addr, p, nil

	Error:
	return nil, 0, err
	}