Source file src/pkg/net/iprawsock_posix.go

     1	// Copyright 2010 The Go Authors.  All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	// +build darwin freebsd linux netbsd openbsd windows
     6	
     7	package net
     8	
     9	import (
    10		"syscall"
    11		"time"
    12	)
    13	
    14	func sockaddrToIP(sa syscall.Sockaddr) Addr {
    15		switch sa := sa.(type) {
    16		case *syscall.SockaddrInet4:
    17			return &IPAddr{IP: sa.Addr[0:]}
    18		case *syscall.SockaddrInet6:
    19			return &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
    20		}
    21		return nil
    22	}
    23	
    24	func (a *IPAddr) family() int {
    25		if a == nil || len(a.IP) <= IPv4len {
    26			return syscall.AF_INET
    27		}
    28		if a.IP.To4() != nil {
    29			return syscall.AF_INET
    30		}
    31		return syscall.AF_INET6
    32	}
    33	
    34	func (a *IPAddr) isWildcard() bool {
    35		if a == nil || a.IP == nil {
    36			return true
    37		}
    38		return a.IP.IsUnspecified()
    39	}
    40	
    41	func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
    42		return ipToSockaddr(family, a.IP, 0, a.Zone)
    43	}
    44	
    45	func (a *IPAddr) toAddr() sockaddr {
    46		if a == nil { // nil *IPAddr
    47			return nil // nil interface
    48		}
    49		return a
    50	}
    51	
    52	// IPConn is the implementation of the Conn and PacketConn interfaces
    53	// for IP network connections.
    54	type IPConn struct {
    55		conn
    56	}
    57	
    58	func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
    59	
    60	// ReadFromIP reads an IP packet from c, copying the payload into b.
    61	// It returns the number of bytes copied into b and the return address
    62	// that was on the packet.
    63	//
    64	// ReadFromIP can be made to time out and return an error with
    65	// Timeout() == true after a fixed time limit; see SetDeadline and
    66	// SetReadDeadline.
    67	func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
    68		if !c.ok() {
    69			return 0, nil, syscall.EINVAL
    70		}
    71		// TODO(cw,rsc): consider using readv if we know the family
    72		// type to avoid the header trim/copy
    73		var addr *IPAddr
    74		n, sa, err := c.fd.ReadFrom(b)
    75		switch sa := sa.(type) {
    76		case *syscall.SockaddrInet4:
    77			addr = &IPAddr{IP: sa.Addr[0:]}
    78			if len(b) >= IPv4len { // discard ipv4 header
    79				hsize := (int(b[0]) & 0xf) * 4
    80				copy(b, b[hsize:])
    81				n -= hsize
    82			}
    83		case *syscall.SockaddrInet6:
    84			addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
    85		}
    86		return n, addr, err
    87	}
    88	
    89	// ReadFrom implements the PacketConn ReadFrom method.
    90	func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
    91		if !c.ok() {
    92			return 0, nil, syscall.EINVAL
    93		}
    94		n, addr, err := c.ReadFromIP(b)
    95		return n, addr.toAddr(), err
    96	}
    97	
    98	// ReadMsgIP reads a packet from c, copying the payload into b and the
    99	// associated out-of-band data into oob.  It returns the number of
   100	// bytes copied into b, the number of bytes copied into oob, the flags
   101	// that were set on the packet and the source address of the packet.
   102	func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
   103		if !c.ok() {
   104			return 0, 0, 0, nil, syscall.EINVAL
   105		}
   106		var sa syscall.Sockaddr
   107		n, oobn, flags, sa, err = c.fd.ReadMsg(b, oob)
   108		switch sa := sa.(type) {
   109		case *syscall.SockaddrInet4:
   110			addr = &IPAddr{IP: sa.Addr[0:]}
   111		case *syscall.SockaddrInet6:
   112			addr = &IPAddr{IP: sa.Addr[0:], Zone: zoneToString(int(sa.ZoneId))}
   113		}
   114		return
   115	}
   116	
   117	// WriteToIP writes an IP packet to addr via c, copying the payload
   118	// from b.
   119	//
   120	// WriteToIP can be made to time out and return an error with
   121	// Timeout() == true after a fixed time limit; see SetDeadline and
   122	// SetWriteDeadline.  On packet-oriented connections, write timeouts
   123	// are rare.
   124	func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
   125		if !c.ok() {
   126			return 0, syscall.EINVAL
   127		}
   128		sa, err := addr.sockaddr(c.fd.family)
   129		if err != nil {
   130			return 0, &OpError{"write", c.fd.net, addr, err}
   131		}
   132		return c.fd.WriteTo(b, sa)
   133	}
   134	
   135	// WriteTo implements the PacketConn WriteTo method.
   136	func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
   137		if !c.ok() {
   138			return 0, syscall.EINVAL
   139		}
   140		a, ok := addr.(*IPAddr)
   141		if !ok {
   142			return 0, &OpError{"write", c.fd.net, addr, syscall.EINVAL}
   143		}
   144		return c.WriteToIP(b, a)
   145	}
   146	
   147	// WriteMsgIP writes a packet to addr via c, copying the payload from
   148	// b and the associated out-of-band data from oob.  It returns the
   149	// number of payload and out-of-band bytes written.
   150	func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
   151		if !c.ok() {
   152			return 0, 0, syscall.EINVAL
   153		}
   154		sa, err := addr.sockaddr(c.fd.family)
   155		if err != nil {
   156			return 0, 0, &OpError{"write", c.fd.net, addr, err}
   157		}
   158		return c.fd.WriteMsg(b, oob, sa)
   159	}
   160	
   161	// DialIP connects to the remote address raddr on the network protocol
   162	// netProto, which must be "ip", "ip4", or "ip6" followed by a colon
   163	// and a protocol number or name.
   164	func DialIP(netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
   165		return dialIP(netProto, laddr, raddr, noDeadline)
   166	}
   167	
   168	func dialIP(netProto string, laddr, raddr *IPAddr, deadline time.Time) (*IPConn, error) {
   169		net, proto, err := parseNetwork(netProto)
   170		if err != nil {
   171			return nil, err
   172		}
   173		switch net {
   174		case "ip", "ip4", "ip6":
   175		default:
   176			return nil, UnknownNetworkError(netProto)
   177		}
   178		if raddr == nil {
   179			return nil, &OpError{"dial", netProto, nil, errMissingAddress}
   180		}
   181		fd, err := internetSocket(net, laddr.toAddr(), raddr.toAddr(), deadline, syscall.SOCK_RAW, proto, "dial", sockaddrToIP)
   182		if err != nil {
   183			return nil, err
   184		}
   185		return newIPConn(fd), nil
   186	}
   187	
   188	// ListenIP listens for incoming IP packets addressed to the local
   189	// address laddr.  The returned connection's ReadFrom and WriteTo
   190	// methods can be used to receive and send IP packets with per-packet
   191	// addressing.
   192	func ListenIP(netProto string, laddr *IPAddr) (*IPConn, error) {
   193		net, proto, err := parseNetwork(netProto)
   194		if err != nil {
   195			return nil, err
   196		}
   197		switch net {
   198		case "ip", "ip4", "ip6":
   199		default:
   200			return nil, UnknownNetworkError(netProto)
   201		}
   202		fd, err := internetSocket(net, laddr.toAddr(), nil, noDeadline, syscall.SOCK_RAW, proto, "listen", sockaddrToIP)
   203		if err != nil {
   204			return nil, err
   205		}
   206		return newIPConn(fd), nil
   207	}

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