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

 // Copyright 2010 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.

 // (Raw) IP sockets

 package net

 import (
 	"os"
 	"sync"
 	"syscall"
 )

 var onceReadProtocols sync.Once

 func sockaddrToIP(sa syscall.Sockaddr) Addr {
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
 		return &IPAddr{sa.Addr[0:]}
 	case *syscall.SockaddrInet6:
 		return &IPAddr{sa.Addr[0:]}
 	}
 	return nil
 }

 // IPAddr represents the address of a IP end point.
 type IPAddr struct {
 	IP IP
 }

 // Network returns the address's network name, "ip".
 func (a *IPAddr) Network() string { return "ip" }

 func (a *IPAddr) String() string {
 	if a == nil {
 		return "<nil>"
 	}
 	return a.IP.String()
 }

 func (a *IPAddr) family() int {
 	if a == nil || len(a.IP) <= 4 {
 		return syscall.AF_INET
 	}
 	if a.IP.To4() != nil {
 		return syscall.AF_INET
 	}
 	return syscall.AF_INET6
 }

 func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, os.Error) {
 	return ipToSockaddr(family, a.IP, 0)
 }

 func (a *IPAddr) toAddr() sockaddr {
 	if a == nil { // nil *IPAddr
 		return nil // nil interface
 	}
 	return a
 }

 // ResolveIPAddr parses addr as a IP address and resolves domain
 // names to numeric addresses on the network net, which must be
 // "ip", "ip4" or "ip6".  A literal IPv6 host address must be
 // enclosed in square brackets, as in "[::]".
 func ResolveIPAddr(net, addr string) (*IPAddr, os.Error) {
 	ip, err := hostToIP(net, addr)
 	if err != nil {
 		return nil, err
 	}
 	return &IPAddr{ip}, nil
 }

 // IPConn is the implementation of the Conn and PacketConn
 // interfaces for IP network connections.
 type IPConn struct {
 	fd *netFD
 }

 func newIPConn(fd *netFD) *IPConn { return &IPConn{fd} }

 func (c *IPConn) ok() bool { return c != nil && c.fd != nil }

 // Implementation of the Conn interface - see Conn for documentation.

 // Read implements the net.Conn Read method.
 func (c *IPConn) Read(b []byte) (n int, err os.Error) {
 	n, _, err = c.ReadFrom(b)
 	return
 }

 // Write implements the net.Conn Write method.
 func (c *IPConn) Write(b []byte) (n int, err os.Error) {
 	if !c.ok() {
 		return 0, os.EINVAL
 	}
 	return c.fd.Write(b)
 }

 // Close closes the IP connection.
 func (c *IPConn) Close() os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	err := c.fd.Close()
 	c.fd = nil
 	return err
 }

 // LocalAddr returns the local network address.
 func (c *IPConn) LocalAddr() Addr {
 	if !c.ok() {
 		return nil
 	}
 	return c.fd.laddr
 }

 // RemoteAddr returns the remote network address, a *IPAddr.
 func (c *IPConn) RemoteAddr() Addr {
 	if !c.ok() {
 		return nil
 	}
 	return c.fd.raddr
 }

 // SetTimeout implements the net.Conn SetTimeout method.
 func (c *IPConn) SetTimeout(nsec int64) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return setTimeout(c.fd, nsec)
 }

 // SetReadTimeout implements the net.Conn SetReadTimeout method.
 func (c *IPConn) SetReadTimeout(nsec int64) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return setReadTimeout(c.fd, nsec)
 }

 // SetWriteTimeout implements the net.Conn SetWriteTimeout method.
 func (c *IPConn) SetWriteTimeout(nsec int64) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return setWriteTimeout(c.fd, nsec)
 }

 // SetReadBuffer sets the size of the operating system's
 // receive buffer associated with the connection.
 func (c *IPConn) SetReadBuffer(bytes int) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return setReadBuffer(c.fd, bytes)
 }

 // SetWriteBuffer sets the size of the operating system's
 // transmit buffer associated with the connection.
 func (c *IPConn) SetWriteBuffer(bytes int) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	return setWriteBuffer(c.fd, bytes)
 }

 // IP-specific methods.

 // ReadFromIP reads a IP packet from c, copying the payload into b.
 // It returns the number of bytes copied into b and the return address
 // that was on the packet.
 //
 // ReadFromIP can be made to time out and return an error with
 // Timeout() == true after a fixed time limit; see SetTimeout and
 // SetReadTimeout.
 func (c *IPConn) ReadFromIP(b []byte) (n int, addr *IPAddr, err os.Error) {
 	if !c.ok() {
 		return 0, nil, os.EINVAL
 	}
 	// TODO(cw,rsc): consider using readv if we know the family
 	// type to avoid the header trim/copy
 	n, sa, err := c.fd.ReadFrom(b)
 	switch sa := sa.(type) {
 	case *syscall.SockaddrInet4:
 		addr = &IPAddr{sa.Addr[0:]}
 		if len(b) >= 4 { // discard ipv4 header
 			hsize := (int(b[0]) & 0xf) * 4
 			copy(b, b[hsize:])
 			n -= hsize
 		}
 	case *syscall.SockaddrInet6:
 		addr = &IPAddr{sa.Addr[0:]}
 	}
 	return
 }

 // ReadFrom implements the net.PacketConn ReadFrom method.
 func (c *IPConn) ReadFrom(b []byte) (n int, addr Addr, err os.Error) {
 	if !c.ok() {
 		return 0, nil, os.EINVAL
 	}
 	n, uaddr, err := c.ReadFromIP(b)
 	return n, uaddr.toAddr(), err
 }

 // WriteToIP writes a IP packet to addr via c, copying the payload from b.
 //
 // WriteToIP can be made to time out and return
 // an error with Timeout() == true after a fixed time limit;
 // see SetTimeout and SetWriteTimeout.
 // On packet-oriented connections, write timeouts are rare.
 func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (n int, err os.Error) {
 	if !c.ok() {
 		return 0, os.EINVAL
 	}
 	sa, err1 := addr.sockaddr(c.fd.family)
 	if err1 != nil {
 		return 0, &OpError{Op: "write", Net: "ip", Addr: addr, Error: err1}
 	}
 	return c.fd.WriteTo(b, sa)
 }

 // WriteTo implements the net.PacketConn WriteTo method.
 func (c *IPConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
 	if !c.ok() {
 		return 0, os.EINVAL
 	}
 	a, ok := addr.(*IPAddr)
 	if !ok {
 		return 0, &OpError{"writeto", "ip", addr, os.EINVAL}
 	}
 	return c.WriteToIP(b, a)
 }

 // Convert "host" into IP address.
 func hostToIP(net, host string) (ip IP, err os.Error) {
 	var addr IP
 	// Try as an IP address.
 	addr = ParseIP(host)
 	if addr == nil {
 		filter := anyaddr
 		if net != "" && net[len(net)-1] == '4' {
 			filter = ipv4only
 		}
 		if net != "" && net[len(net)-1] == '6' {
 			filter = ipv6only
 		}
 		// Not an IP address.  Try as a DNS name.
 		addrs, err1 := LookupHost(host)
 		if err1 != nil {
 			err = err1
 			goto Error
 		}
 		addr = firstFavoriteAddr(filter, addrs)
 		if addr == nil {
 			// should not happen
 			err = &AddrError{"LookupHost returned no suitable address", addrs[0]}
 			goto Error
 		}
 	}
 	return addr, nil
 Error:
 	return nil, err
 }

 var protocols map[string]int

 func readProtocols() {
 	protocols = make(map[string]int)
 	if file, err := open("/etc/protocols"); err == nil {
 		for line, ok := file.readLine(); ok; line, ok = file.readLine() {
 			// tcp    6   TCP    # transmission control protocol
 			if i := byteIndex(line, '#'); i >= 0 {
 				line = line[0:i]
 			}
 			f := getFields(line)
 			if len(f) < 2 {
 				continue
 			}
 			if proto, _, ok := dtoi(f[1], 0); ok {
 				protocols[f[0]] = proto
 				for _, alias := range f[2:] {
 					protocols[alias] = proto
 				}
 			}
 		}
 		file.close()
 	}
 }

 func splitNetProto(netProto string) (net string, proto int, err os.Error) {
 	onceReadProtocols.Do(readProtocols)
 	i := last(netProto, ':')
 	if i < 0 { // no colon
 		return "", 0, os.NewError("no IP protocol specified")
 	}
 	net = netProto[0:i]
 	protostr := netProto[i+1:]
 	proto, i, ok := dtoi(protostr, 0)
 	if !ok || i != len(protostr) {
 		// lookup by name
 		proto, ok = protocols[protostr]
 		if ok {
 			return
 		}
 	}
 	return
 }

 // DialIP connects to the remote address raddr on the network net,
 // which must be "ip", "ip4", or "ip6".
 func DialIP(netProto string, laddr, raddr *IPAddr) (c *IPConn, err os.Error) {
 	net, proto, err := splitNetProto(netProto)
 	if err != nil {
 		return
 	}
 	switch net {
 	case "ip", "ip4", "ip6":
 	default:
 		return nil, UnknownNetworkError(net)
 	}
 	if raddr == nil {
 		return nil, &OpError{"dial", "ip", nil, errMissingAddress}
 	}
 	fd, e := internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
 	if e != nil {
 		return nil, e
 	}
 	return newIPConn(fd), nil
 }

 // ListenIP listens for incoming IP packets addressed to the
 // local address laddr.  The returned connection c's ReadFrom
 // and WriteTo methods can be used to receive and send IP
 // packets with per-packet addressing.
 func ListenIP(netProto string, laddr *IPAddr) (c *IPConn, err os.Error) {
 	net, proto, err := splitNetProto(netProto)
 	if err != nil {
 		return
 	}
 	switch net {
 	case "ip", "ip4", "ip6":
 	default:
 		return nil, UnknownNetworkError(net)
 	}
 	fd, e := internetSocket(net, laddr.toAddr(), nil, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
 	if e != nil {
 		return nil, e
 	}
 	return newIPConn(fd), nil
 }

 // BindToDevice binds an IPConn to a network interface.
 func (c *IPConn) BindToDevice(device string) os.Error {
 	if !c.ok() {
 		return os.EINVAL
 	}
 	c.fd.incref()
 	defer c.fd.decref()
 	return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
 }
	// Copyright 2010 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.

	// (Raw) IP sockets

	package net

	import (
	"os"
	"sync"
	"syscall"
	)

	var onceReadProtocols sync.Once

	func sockaddrToIP(sa syscall.Sockaddr) Addr {
	switch sa := sa.(type) {
	case *syscall.SockaddrInet4:
	return &IPAddr{sa.Addr[0:]}
	case *syscall.SockaddrInet6:
	return &IPAddr{sa.Addr[0:]}
	}
	return nil
	}

	// IPAddr represents the address of a IP end point.
	type IPAddr struct {
	IP IP
	}

	// Network returns the address's network name, "ip".
	func (a *IPAddr) Network() string { return "ip" }

	func (a *IPAddr) String() string {
	if a == nil {
	return "<nil>"
	}
	return a.IP.String()
	}

	func (a *IPAddr) family() int {
	if a == nil \|\| len(a.IP) <= 4 {
	return syscall.AF_INET
	}
	if a.IP.To4() != nil {
	return syscall.AF_INET
	}
	return syscall.AF_INET6
	}

	func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, os.Error) {
	return ipToSockaddr(family, a.IP, 0)
	}

	func (a *IPAddr) toAddr() sockaddr {
	if a == nil { // nil *IPAddr
	return nil // nil interface
	}
	return a
	}

	// ResolveIPAddr parses addr as a IP address and resolves domain
	// names to numeric addresses on the network net, which must be
	// "ip", "ip4" or "ip6". A literal IPv6 host address must be
	// enclosed in square brackets, as in "[::]".
	func ResolveIPAddr(net, addr string) (*IPAddr, os.Error) {
	ip, err := hostToIP(net, addr)
	if err != nil {
	return nil, err
	}
	return &IPAddr{ip}, nil
	}

	// IPConn is the implementation of the Conn and PacketConn
	// interfaces for IP network connections.
	type IPConn struct {
	fd *netFD
	}

	func newIPConn(fd netFD) IPConn { return &IPConn{fd} }

	func (c *IPConn) ok() bool { return c != nil && c.fd != nil }

	// Implementation of the Conn interface - see Conn for documentation.

	// Read implements the net.Conn Read method.
	func (c *IPConn) Read(b []byte) (n int, err os.Error) {
	n, _, err = c.ReadFrom(b)
	return
	}

	// Write implements the net.Conn Write method.
	func (c *IPConn) Write(b []byte) (n int, err os.Error) {
	if !c.ok() {
	return 0, os.EINVAL
	}
	return c.fd.Write(b)
	}

	// Close closes the IP connection.
	func (c *IPConn) Close() os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	err := c.fd.Close()
	c.fd = nil
	return err
	}

	// LocalAddr returns the local network address.
	func (c *IPConn) LocalAddr() Addr {
	if !c.ok() {
	return nil
	}
	return c.fd.laddr
	}

	// RemoteAddr returns the remote network address, a *IPAddr.
	func (c *IPConn) RemoteAddr() Addr {
	if !c.ok() {
	return nil
	}
	return c.fd.raddr
	}

	// SetTimeout implements the net.Conn SetTimeout method.
	func (c *IPConn) SetTimeout(nsec int64) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	return setTimeout(c.fd, nsec)
	}

	// SetReadTimeout implements the net.Conn SetReadTimeout method.
	func (c *IPConn) SetReadTimeout(nsec int64) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	return setReadTimeout(c.fd, nsec)
	}

	// SetWriteTimeout implements the net.Conn SetWriteTimeout method.
	func (c *IPConn) SetWriteTimeout(nsec int64) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	return setWriteTimeout(c.fd, nsec)
	}

	// SetReadBuffer sets the size of the operating system's
	// receive buffer associated with the connection.
	func (c *IPConn) SetReadBuffer(bytes int) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	return setReadBuffer(c.fd, bytes)
	}

	// SetWriteBuffer sets the size of the operating system's
	// transmit buffer associated with the connection.
	func (c *IPConn) SetWriteBuffer(bytes int) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	return setWriteBuffer(c.fd, bytes)
	}

	// IP-specific methods.

	// ReadFromIP reads a IP packet from c, copying the payload into b.
	// It returns the number of bytes copied into b and the return address
	// that was on the packet.
	//
	// ReadFromIP can be made to time out and return an error with
	// Timeout() == true after a fixed time limit; see SetTimeout and
	// SetReadTimeout.
	func (c IPConn) ReadFromIP(b []byte) (n int, addr IPAddr, err os.Error) {
	if !c.ok() {
	return 0, nil, os.EINVAL
	}
	// TODO(cw,rsc): consider using readv if we know the family
	// type to avoid the header trim/copy
	n, sa, err := c.fd.ReadFrom(b)
	switch sa := sa.(type) {
	case *syscall.SockaddrInet4:
	addr = &IPAddr{sa.Addr[0:]}
	if len(b) >= 4 { // discard ipv4 header
	hsize := (int(b[0]) & 0xf) * 4
	copy(b, b[hsize:])
	n -= hsize
	}
	case *syscall.SockaddrInet6:
	addr = &IPAddr{sa.Addr[0:]}
	}
	return
	}

	// ReadFrom implements the net.PacketConn ReadFrom method.
	func (c *IPConn) ReadFrom(b []byte) (n int, addr Addr, err os.Error) {
	if !c.ok() {
	return 0, nil, os.EINVAL
	}
	n, uaddr, err := c.ReadFromIP(b)
	return n, uaddr.toAddr(), err
	}

	// WriteToIP writes a IP packet to addr via c, copying the payload from b.
	//
	// WriteToIP can be made to time out and return
	// an error with Timeout() == true after a fixed time limit;
	// see SetTimeout and SetWriteTimeout.
	// On packet-oriented connections, write timeouts are rare.
	func (c IPConn) WriteToIP(b []byte, addr IPAddr) (n int, err os.Error) {
	if !c.ok() {
	return 0, os.EINVAL
	}
	sa, err1 := addr.sockaddr(c.fd.family)
	if err1 != nil {
	return 0, &OpError{Op: "write", Net: "ip", Addr: addr, Error: err1}
	}
	return c.fd.WriteTo(b, sa)
	}

	// WriteTo implements the net.PacketConn WriteTo method.
	func (c *IPConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
	if !c.ok() {
	return 0, os.EINVAL
	}
	a, ok := addr.(*IPAddr)
	if !ok {
	return 0, &OpError{"writeto", "ip", addr, os.EINVAL}
	}
	return c.WriteToIP(b, a)
	}

	// Convert "host" into IP address.
	func hostToIP(net, host string) (ip IP, err os.Error) {
	var addr IP
	// Try as an IP address.
	addr = ParseIP(host)
	if addr == nil {
	filter := anyaddr
	if net != "" && net[len(net)-1] == '4' {
	filter = ipv4only
	}
	if net != "" && net[len(net)-1] == '6' {
	filter = ipv6only
	}
	// Not an IP address. Try as a DNS name.
	addrs, err1 := LookupHost(host)
	if err1 != nil {
	err = err1
	goto Error
	}
	addr = firstFavoriteAddr(filter, addrs)
	if addr == nil {
	// should not happen
	err = &AddrError{"LookupHost returned no suitable address", addrs[0]}
	goto Error
	}
	}
	return addr, nil
	Error:
	return nil, err
	}

	var protocols map[string]int

	func readProtocols() {
	protocols = make(map[string]int)
	if file, err := open("/etc/protocols"); err == nil {
	for line, ok := file.readLine(); ok; line, ok = file.readLine() {
	// tcp 6 TCP # transmission control protocol
	if i := byteIndex(line, '#'); i >= 0 {
	line = line[0:i]
	}
	f := getFields(line)
	if len(f) < 2 {
	continue
	}
	if proto, _, ok := dtoi(f[1], 0); ok {
	protocols[f[0]] = proto
	for _, alias := range f[2:] {
	protocols[alias] = proto
	}
	}
	}
	file.close()
	}
	}

	func splitNetProto(netProto string) (net string, proto int, err os.Error) {
	onceReadProtocols.Do(readProtocols)
	i := last(netProto, ':')
	if i < 0 { // no colon
	return "", 0, os.NewError("no IP protocol specified")
	}
	net = netProto[0:i]
	protostr := netProto[i+1:]
	proto, i, ok := dtoi(protostr, 0)
	if !ok \|\| i != len(protostr) {
	// lookup by name
	proto, ok = protocols[protostr]
	if ok {
	return
	}
	}
	return
	}

	// DialIP connects to the remote address raddr on the network net,
	// which must be "ip", "ip4", or "ip6".
	func DialIP(netProto string, laddr, raddr IPAddr) (c IPConn, err os.Error) {
	net, proto, err := splitNetProto(netProto)
	if err != nil {
	return
	}
	switch net {
	case "ip", "ip4", "ip6":
	default:
	return nil, UnknownNetworkError(net)
	}
	if raddr == nil {
	return nil, &OpError{"dial", "ip", nil, errMissingAddress}
	}
	fd, e := internetSocket(net, laddr.toAddr(), raddr.toAddr(), syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
	if e != nil {
	return nil, e
	}
	return newIPConn(fd), nil
	}

	// ListenIP listens for incoming IP packets addressed to the
	// local address laddr. The returned connection c's ReadFrom
	// and WriteTo methods can be used to receive and send IP
	// packets with per-packet addressing.
	func ListenIP(netProto string, laddr IPAddr) (c IPConn, err os.Error) {
	net, proto, err := splitNetProto(netProto)
	if err != nil {
	return
	}
	switch net {
	case "ip", "ip4", "ip6":
	default:
	return nil, UnknownNetworkError(net)
	}
	fd, e := internetSocket(net, laddr.toAddr(), nil, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
	if e != nil {
	return nil, e
	}
	return newIPConn(fd), nil
	}

	// BindToDevice binds an IPConn to a network interface.
	func (c *IPConn) BindToDevice(device string) os.Error {
	if !c.ok() {
	return os.EINVAL
	}
	c.fd.incref()
	defer c.fd.decref()
	return os.NewSyscallError("setsockopt", syscall.BindToDevice(c.fd.sysfd, device))
	}