| // 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 ip := a.IP.To4(); ip != 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. A literal IPv6 host address must be |
| // enclosed in square brackets, as in "[::]". |
| func ResolveIPAddr(addr string) (*IPAddr, os.Error) { |
| ip, err := hostToIP(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(host string) (ip IP, err os.Error) { |
| var addr IP |
| // 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 |
| } |
| } |
| |
| 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 netProtoSplit(netProto string) (net string, proto int, err os.Error) { |
| onceReadProtocols.Do(readProtocols) |
| i := last(netProto, ':') |
| if i < 0 { // no colon |
| return "", 0, os.ErrorString("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 := netProtoSplit(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 := netProtoSplit(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)) |
| } |