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 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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