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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 returns an address of IP end point.
  //
  // The network must be an IP network name.
  //
  // If the host in the address parameter is not a literal IP address,
  // ResolveIPAddr resolves the address to an address of IP end point.
  // Otherwise, it parses the address as a literal IP address.
  // The address parameter can use a host name, but this is not
  // recommended, because it will return at most one of the host name's
  // IP addresses.
  //
  // See func Dial for a description of the network and address
  // parameters.
  func ResolveIPAddr(network, address string) (*IPAddr, error) {
  	if network == "" { // a hint wildcard for Go 1.0 undocumented behavior
  		network = "ip"
  	}
  	afnet, _, err := parseNetwork(context.Background(), network, false)
  	if err != nil {
  		return nil, err
  	}
  	switch afnet {
  	case "ip", "ip4", "ip6":
  	default:
  		return nil, UnknownNetworkError(network)
  	}
  	addrs, err := DefaultResolver.internetAddrList(context.Background(), afnet, address)
  	if err != nil {
  		return nil, err
  	}
  	return addrs.forResolve(network, address).(*IPAddr), nil
  }
  
  // IPConn is the implementation of the Conn and PacketConn interfaces
  // for IP network connections.
  type IPConn struct {
  	conn
  }
  
  // SyscallConn returns a raw network connection.
  // This implements the syscall.Conn interface.
  func (c *IPConn) SyscallConn() (syscall.RawConn, error) {
  	if !c.ok() {
  		return nil, syscall.EINVAL
  	}
  	return newRawConn(c.fd)
  }
  
  // ReadFromIP acts like ReadFrom but returns an IPAddr.
  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 message 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 message and the source address of the message.
  //
  // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
  // used to manipulate IP-level socket options in oob.
  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 acts like WriteTo but takes an IPAddr.
  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 message 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.
  //
  // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
  // used to manipulate IP-level socket options in oob.
  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 acts like Dial for IP networks.
  //
  // The network must be an IP network name; see func Dial for details.
  //
  // If laddr is nil, a local address is automatically chosen.
  // If the IP field of raddr is nil or an unspecified IP address, the
  // local system is assumed.
  func DialIP(network string, laddr, raddr *IPAddr) (*IPConn, error) {
  	c, err := dialIP(context.Background(), network, laddr, raddr)
  	if err != nil {
  		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
  	}
  	return c, nil
  }
  
  // ListenIP acts like ListenPacket for IP networks.
  //
  // The network must be an IP network name; see func Dial for details.
  //
  // If the IP field of laddr is nil or an unspecified IP address,
  // ListenIP listens on all available IP addresses of the local system
  // except multicast IP addresses.
  func ListenIP(network string, laddr *IPAddr) (*IPConn, error) {
  	c, err := listenIP(context.Background(), network, laddr)
  	if err != nil {
  		return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
  	}
  	return c, nil
  }
  

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