...
Run Format

Source file src/net/iprawsock.go

Documentation: net

  // 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.
  
  package net
  
  import (
  	"context"
  	"syscall"
  )
  
  // BUG(mikio): On every POSIX platform, reads from the "ip4" network
  // using the ReadFrom or ReadFromIP method might not return a complete
  // IPv4 packet, including its header, even if there is space
  // available. This can occur even in cases where Read or ReadMsgIP
  // could return a complete packet. For this reason, it is recommended
  // that you do not use these methods if it is important to receive a
  // full packet.
  //
  // The Go 1 compatibility guidelines make it impossible for us to
  // change the behavior of these methods; use Read or ReadMsgIP
  // instead.
  
  // BUG(mikio): On NaCl, Plan 9 and Windows, the ReadMsgIP and
  // WriteMsgIP methods of IPConn are not implemented.
  
  // BUG(mikio): On Windows, the File method of IPConn is not
  // implemented.
  
  // IPAddr represents the address of an IP end point.
  type IPAddr struct {
  	IP   IP
  	Zone string // IPv6 scoped addressing zone
  }
  
  // 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>"
  	}
  	ip := ipEmptyString(a.IP)
  	if a.Zone != "" {
  		return ip + "%" + a.Zone
  	}
  	return ip
  }
  
  func (a *IPAddr) isWildcard() bool {
  	if a == nil || a.IP == nil {
  		return true
  	}
  	return a.IP.IsUnspecified()
  }
  
  func (a *IPAddr) opAddr() Addr {
  	if a == nil {
  		return nil
  	}
  	return a
  }
  
  // ResolveIPAddr parses addr as an IP address of the form "host" or
  // "ipv6-host%zone" and resolves the domain name on the network net,
  // which must be "ip", "ip4" or "ip6".
  //
  // Resolving a hostname is not recommended because this returns at most
  // one of its IP addresses.
  func ResolveIPAddr(net, addr string) (*IPAddr, error) {
  	if net == "" { // a hint wildcard for Go 1.0 undocumented behavior
  		net = "ip"
  	}
  	afnet, _, err := parseNetwork(context.Background(), net)
  	if err != nil {
  		return nil, err
  	}
  	switch afnet {
  	case "ip", "ip4", "ip6":
  	default:
  		return nil, UnknownNetworkError(net)
  	}
  	addrs, err := DefaultResolver.internetAddrList(context.Background(), afnet, addr)
  	if err != nil {
  		return nil, err
  	}
  	return addrs.first(isIPv4).(*IPAddr), nil
  }
  
  // IPConn is the implementation of the Conn and PacketConn interfaces
  // for IP network connections.
  type IPConn struct {
  	conn
  }
  
  // ReadFromIP reads an 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 SetDeadline and
  // SetReadDeadline.
  func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
  	if !c.ok() {
  		return 0, nil, syscall.EINVAL
  	}
  	n, addr, err := c.readFrom(b)
  	if err != nil {
  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  	}
  	return n, addr, err
  }
  
  // ReadFrom implements the PacketConn ReadFrom method.
  func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
  	if !c.ok() {
  		return 0, nil, syscall.EINVAL
  	}
  	n, addr, err := c.readFrom(b)
  	if err != nil {
  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  	}
  	if addr == nil {
  		return n, nil, err
  	}
  	return n, addr, err
  }
  
  // ReadMsgIP reads a packet from c, copying the payload into b and the
  // associated out-of-band data into oob. It returns the number of
  // bytes copied into b, the number of bytes copied into oob, the flags
  // that were set on the packet and the source address of the packet.
  func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
  	if !c.ok() {
  		return 0, 0, 0, nil, syscall.EINVAL
  	}
  	n, oobn, flags, addr, err = c.readMsg(b, oob)
  	if err != nil {
  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  	}
  	return
  }
  
  // WriteToIP writes an 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 SetDeadline and
  // SetWriteDeadline. On packet-oriented connections, write timeouts
  // are rare.
  func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
  	if !c.ok() {
  		return 0, syscall.EINVAL
  	}
  	n, err := c.writeTo(b, addr)
  	if err != nil {
  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
  	}
  	return n, err
  }
  
  // WriteTo implements the PacketConn WriteTo method.
  func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
  	if !c.ok() {
  		return 0, syscall.EINVAL
  	}
  	a, ok := addr.(*IPAddr)
  	if !ok {
  		return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
  	}
  	n, err := c.writeTo(b, a)
  	if err != nil {
  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
  	}
  	return n, err
  }
  
  // WriteMsgIP writes a packet to addr via c, copying the payload from
  // b and the associated out-of-band data from oob. It returns the
  // number of payload and out-of-band bytes written.
  func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
  	if !c.ok() {
  		return 0, 0, syscall.EINVAL
  	}
  	n, oobn, err = c.writeMsg(b, oob, addr)
  	if err != nil {
  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
  	}
  	return
  }
  
  func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
  
  // DialIP connects to the remote address raddr on the network protocol
  // netProto, which must be "ip", "ip4", or "ip6" followed by a colon
  // and a protocol number or name.
  func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
  	c, err := dialIP(context.Background(), netProto, laddr, raddr)
  	if err != nil {
  		return nil, &OpError{Op: "dial", Net: netProto, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
  	}
  	return c, nil
  }
  
  // ListenIP listens for incoming IP packets addressed to the local
  // address laddr. The returned connection's ReadFrom and WriteTo
  // methods can be used to receive and send IP packets with per-packet
  // addressing.
  func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
  	c, err := listenIP(context.Background(), netProto, laddr)
  	if err != nil {
  		return nil, &OpError{Op: "listen", Net: netProto, Source: nil, Addr: laddr.opAddr(), Err: err}
  	}
  	return c, nil
  }
  

View as plain text