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 5package net 6 7import ( 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 NaCl, Plan 9 and Windows, the ReadMsgIP and 25// WriteMsgIP methods of 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. 31type IPAddr struct { 32 IP IP 33 Zone string // IPv6 scoped addressing zone 34} 35 36// Network returns the address's network name, "ip". 37func (a *IPAddr) Network() string { return "ip" } 38 39func (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 50func (a *IPAddr) isWildcard() bool { 51 if a == nil || a.IP == nil { 52 return true 53 } 54 return a.IP.IsUnspecified() 55} 56 57func (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. 77func 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. 99type IPConn struct { 100 conn 101} 102 103// SyscallConn returns a raw network connection. 104// This implements the syscall.Conn interface. 105func (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. 113func (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. 125func (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. 146func (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. 158func (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. 170func (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. 191func (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 202func 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. 211func DialIP(network string, laddr, raddr *IPAddr) (*IPConn, error) { 212 c, err := dialIP(context.Background(), network, laddr, raddr) 213 if err != nil { 214 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err} 215 } 216 return c, nil 217} 218 219// ListenIP acts like ListenPacket for IP networks. 220// 221// The network must be an IP network name; see func Dial for details. 222// 223// If the IP field of laddr is nil or an unspecified IP address, 224// ListenIP listens on all available IP addresses of the local system 225// except multicast IP addresses. 226func ListenIP(network string, laddr *IPAddr) (*IPConn, error) { 227 c, err := listenIP(context.Background(), network, laddr) 228 if err != nil { 229 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err} 230 } 231 return c, nil 232} 233