306 lines
7.3 KiB
Go
306 lines
7.3 KiB
Go
|
// 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
|
||
|
}
|
||
|
|
||
|
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
|
||
|
}
|
||
|
|
||
|
// 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)
|
||
|
}
|
||
|
|
||
|
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))
|
||
|
}
|