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Source file src/net/iprawsock.go

Documentation: net

     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  package net
     6  
     7  import (
     8  	"context"
     9  	"syscall"
    10  )
    11  
    12  // BUG(mikio): On every POSIX platform, reads from the "ip4" network
    13  // using the ReadFrom or ReadFromIP method might not return a complete
    14  // IPv4 packet, including its header, even if there is space
    15  // available. This can occur even in cases where Read or ReadMsgIP
    16  // could return a complete packet. For this reason, it is recommended
    17  // that you do not use these methods if it is important to receive a
    18  // full packet.
    19  //
    20  // The Go 1 compatibility guidelines make it impossible for us to
    21  // change the behavior of these methods; use Read or ReadMsgIP
    22  // instead.
    23  
    24  // BUG(mikio): On JS, NaCl and Plan 9, methods and functions related
    25  // to IPConn are not implemented.
    26  
    27  // BUG(mikio): On Windows, the File method of IPConn is not
    28  // implemented.
    29  
    30  // IPAddr represents the address of an IP end point.
    31  type IPAddr struct {
    32  	IP   IP
    33  	Zone string // IPv6 scoped addressing zone
    34  }
    35  
    36  // Network returns the address's network name, "ip".
    37  func (a *IPAddr) Network() string { return "ip" }
    38  
    39  func (a *IPAddr) String() string {
    40  	if a == nil {
    41  		return "<nil>"
    42  	}
    43  	ip := ipEmptyString(a.IP)
    44  	if a.Zone != "" {
    45  		return ip + "%" + a.Zone
    46  	}
    47  	return ip
    48  }
    49  
    50  func (a *IPAddr) isWildcard() bool {
    51  	if a == nil || a.IP == nil {
    52  		return true
    53  	}
    54  	return a.IP.IsUnspecified()
    55  }
    56  
    57  func (a *IPAddr) opAddr() Addr {
    58  	if a == nil {
    59  		return nil
    60  	}
    61  	return a
    62  }
    63  
    64  // ResolveIPAddr returns an address of IP end point.
    65  //
    66  // The network must be an IP network name.
    67  //
    68  // If the host in the address parameter is not a literal IP address,
    69  // ResolveIPAddr resolves the address to an address of IP end point.
    70  // Otherwise, it parses the address as a literal IP address.
    71  // The address parameter can use a host name, but this is not
    72  // recommended, because it will return at most one of the host name's
    73  // IP addresses.
    74  //
    75  // See func Dial for a description of the network and address
    76  // parameters.
    77  func ResolveIPAddr(network, address string) (*IPAddr, error) {
    78  	if network == "" { // a hint wildcard for Go 1.0 undocumented behavior
    79  		network = "ip"
    80  	}
    81  	afnet, _, err := parseNetwork(context.Background(), network, false)
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  	switch afnet {
    86  	case "ip", "ip4", "ip6":
    87  	default:
    88  		return nil, UnknownNetworkError(network)
    89  	}
    90  	addrs, err := DefaultResolver.internetAddrList(context.Background(), afnet, address)
    91  	if err != nil {
    92  		return nil, err
    93  	}
    94  	return addrs.forResolve(network, address).(*IPAddr), nil
    95  }
    96  
    97  // IPConn is the implementation of the Conn and PacketConn interfaces
    98  // for IP network connections.
    99  type IPConn struct {
   100  	conn
   101  }
   102  
   103  // SyscallConn returns a raw network connection.
   104  // This implements the syscall.Conn interface.
   105  func (c *IPConn) SyscallConn() (syscall.RawConn, error) {
   106  	if !c.ok() {
   107  		return nil, syscall.EINVAL
   108  	}
   109  	return newRawConn(c.fd)
   110  }
   111  
   112  // ReadFromIP acts like ReadFrom but returns an IPAddr.
   113  func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
   114  	if !c.ok() {
   115  		return 0, nil, syscall.EINVAL
   116  	}
   117  	n, addr, err := c.readFrom(b)
   118  	if err != nil {
   119  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
   120  	}
   121  	return n, addr, err
   122  }
   123  
   124  // ReadFrom implements the PacketConn ReadFrom method.
   125  func (c *IPConn) ReadFrom(b []byte) (int, Addr, error) {
   126  	if !c.ok() {
   127  		return 0, nil, syscall.EINVAL
   128  	}
   129  	n, addr, err := c.readFrom(b)
   130  	if err != nil {
   131  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
   132  	}
   133  	if addr == nil {
   134  		return n, nil, err
   135  	}
   136  	return n, addr, err
   137  }
   138  
   139  // ReadMsgIP reads a message from c, copying the payload into b and
   140  // the associated out-of-band data into oob. It returns the number of
   141  // bytes copied into b, the number of bytes copied into oob, the flags
   142  // that were set on the message and the source address of the message.
   143  //
   144  // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
   145  // used to manipulate IP-level socket options in oob.
   146  func (c *IPConn) ReadMsgIP(b, oob []byte) (n, oobn, flags int, addr *IPAddr, err error) {
   147  	if !c.ok() {
   148  		return 0, 0, 0, nil, syscall.EINVAL
   149  	}
   150  	n, oobn, flags, addr, err = c.readMsg(b, oob)
   151  	if err != nil {
   152  		err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
   153  	}
   154  	return
   155  }
   156  
   157  // WriteToIP acts like WriteTo but takes an IPAddr.
   158  func (c *IPConn) WriteToIP(b []byte, addr *IPAddr) (int, error) {
   159  	if !c.ok() {
   160  		return 0, syscall.EINVAL
   161  	}
   162  	n, err := c.writeTo(b, addr)
   163  	if err != nil {
   164  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
   165  	}
   166  	return n, err
   167  }
   168  
   169  // WriteTo implements the PacketConn WriteTo method.
   170  func (c *IPConn) WriteTo(b []byte, addr Addr) (int, error) {
   171  	if !c.ok() {
   172  		return 0, syscall.EINVAL
   173  	}
   174  	a, ok := addr.(*IPAddr)
   175  	if !ok {
   176  		return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
   177  	}
   178  	n, err := c.writeTo(b, a)
   179  	if err != nil {
   180  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
   181  	}
   182  	return n, err
   183  }
   184  
   185  // WriteMsgIP writes a message to addr via c, copying the payload from
   186  // b and the associated out-of-band data from oob. It returns the
   187  // number of payload and out-of-band bytes written.
   188  //
   189  // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
   190  // used to manipulate IP-level socket options in oob.
   191  func (c *IPConn) WriteMsgIP(b, oob []byte, addr *IPAddr) (n, oobn int, err error) {
   192  	if !c.ok() {
   193  		return 0, 0, syscall.EINVAL
   194  	}
   195  	n, oobn, err = c.writeMsg(b, oob, addr)
   196  	if err != nil {
   197  		err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
   198  	}
   199  	return
   200  }
   201  
   202  func newIPConn(fd *netFD) *IPConn { return &IPConn{conn{fd}} }
   203  
   204  // DialIP acts like Dial for IP networks.
   205  //
   206  // The network must be an IP network name; see func Dial for details.
   207  //
   208  // If laddr is nil, a local address is automatically chosen.
   209  // If the IP field of raddr is nil or an unspecified IP address, the
   210  // local system is assumed.
   211  func DialIP(network string, laddr, raddr *IPAddr) (*IPConn, error) {
   212  	if raddr == nil {
   213  		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
   214  	}
   215  	sd := &sysDialer{network: network, address: raddr.String()}
   216  	c, err := sd.dialIP(context.Background(), laddr, raddr)
   217  	if err != nil {
   218  		return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
   219  	}
   220  	return c, nil
   221  }
   222  
   223  // ListenIP acts like ListenPacket for IP networks.
   224  //
   225  // The network must be an IP network name; see func Dial for details.
   226  //
   227  // If the IP field of laddr is nil or an unspecified IP address,
   228  // ListenIP listens on all available IP addresses of the local system
   229  // except multicast IP addresses.
   230  func ListenIP(network string, laddr *IPAddr) (*IPConn, error) {
   231  	if laddr == nil {
   232  		laddr = &IPAddr{}
   233  	}
   234  	sl := &sysListener{network: network, address: laddr.String()}
   235  	c, err := sl.listenIP(context.Background(), laddr)
   236  	if err != nil {
   237  		return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
   238  	}
   239  	return c, nil
   240  }
   241  

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