github.com/gidoBOSSftw5731/go/src@v0.0.0-20210226122457-d24b0edbf019/net/udpsock.go (about) 1 // Copyright 2009 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 Plan 9, the ReadMsgUDP and 13 // WriteMsgUDP methods of UDPConn are not implemented. 14 15 // BUG(mikio): On Windows, the File method of UDPConn is not 16 // implemented. 17 18 // BUG(mikio): On JS, methods and functions related to UDPConn are not 19 // implemented. 20 21 // UDPAddr represents the address of a UDP end point. 22 type UDPAddr struct { 23 IP IP 24 Port int 25 Zone string // IPv6 scoped addressing zone 26 } 27 28 // Network returns the address's network name, "udp". 29 func (a *UDPAddr) Network() string { return "udp" } 30 31 func (a *UDPAddr) String() string { 32 if a == nil { 33 return "<nil>" 34 } 35 ip := ipEmptyString(a.IP) 36 if a.Zone != "" { 37 return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port)) 38 } 39 return JoinHostPort(ip, itoa(a.Port)) 40 } 41 42 func (a *UDPAddr) isWildcard() bool { 43 if a == nil || a.IP == nil { 44 return true 45 } 46 return a.IP.IsUnspecified() 47 } 48 49 func (a *UDPAddr) opAddr() Addr { 50 if a == nil { 51 return nil 52 } 53 return a 54 } 55 56 // ResolveUDPAddr returns an address of UDP end point. 57 // 58 // The network must be a UDP network name. 59 // 60 // If the host in the address parameter is not a literal IP address or 61 // the port is not a literal port number, ResolveUDPAddr resolves the 62 // address to an address of UDP end point. 63 // Otherwise, it parses the address as a pair of literal IP address 64 // and port number. 65 // The address parameter can use a host name, but this is not 66 // recommended, because it will return at most one of the host name's 67 // IP addresses. 68 // 69 // See func Dial for a description of the network and address 70 // parameters. 71 func ResolveUDPAddr(network, address string) (*UDPAddr, error) { 72 switch network { 73 case "udp", "udp4", "udp6": 74 case "": // a hint wildcard for Go 1.0 undocumented behavior 75 network = "udp" 76 default: 77 return nil, UnknownNetworkError(network) 78 } 79 addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address) 80 if err != nil { 81 return nil, err 82 } 83 return addrs.forResolve(network, address).(*UDPAddr), nil 84 } 85 86 // UDPConn is the implementation of the Conn and PacketConn interfaces 87 // for UDP network connections. 88 type UDPConn struct { 89 conn 90 } 91 92 // SyscallConn returns a raw network connection. 93 // This implements the syscall.Conn interface. 94 func (c *UDPConn) SyscallConn() (syscall.RawConn, error) { 95 if !c.ok() { 96 return nil, syscall.EINVAL 97 } 98 return newRawConn(c.fd) 99 } 100 101 // ReadFromUDP acts like ReadFrom but returns a UDPAddr. 102 func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) { 103 if !c.ok() { 104 return 0, nil, syscall.EINVAL 105 } 106 n, addr, err := c.readFrom(b) 107 if err != nil { 108 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 109 } 110 return n, addr, err 111 } 112 113 // ReadFrom implements the PacketConn ReadFrom method. 114 func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) { 115 if !c.ok() { 116 return 0, nil, syscall.EINVAL 117 } 118 n, addr, err := c.readFrom(b) 119 if err != nil { 120 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 121 } 122 if addr == nil { 123 return n, nil, err 124 } 125 return n, addr, err 126 } 127 128 // ReadMsgUDP reads a message from c, copying the payload into b and 129 // the associated out-of-band data into oob. It returns the number of 130 // bytes copied into b, the number of bytes copied into oob, the flags 131 // that were set on the message and the source address of the message. 132 // 133 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be 134 // used to manipulate IP-level socket options in oob. 135 func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) { 136 if !c.ok() { 137 return 0, 0, 0, nil, syscall.EINVAL 138 } 139 n, oobn, flags, addr, err = c.readMsg(b, oob) 140 if err != nil { 141 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err} 142 } 143 return 144 } 145 146 // WriteToUDP acts like WriteTo but takes a UDPAddr. 147 func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) { 148 if !c.ok() { 149 return 0, syscall.EINVAL 150 } 151 n, err := c.writeTo(b, addr) 152 if err != nil { 153 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err} 154 } 155 return n, err 156 } 157 158 // WriteTo implements the PacketConn WriteTo method. 159 func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) { 160 if !c.ok() { 161 return 0, syscall.EINVAL 162 } 163 a, ok := addr.(*UDPAddr) 164 if !ok { 165 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL} 166 } 167 n, err := c.writeTo(b, a) 168 if err != nil { 169 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err} 170 } 171 return n, err 172 } 173 174 // WriteMsgUDP writes a message to addr via c if c isn't connected, or 175 // to c's remote address if c is connected (in which case addr must be 176 // nil). The payload is copied from b and the associated out-of-band 177 // data is copied from oob. It returns the number of payload and 178 // out-of-band bytes written. 179 // 180 // The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be 181 // used to manipulate IP-level socket options in oob. 182 func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) { 183 if !c.ok() { 184 return 0, 0, syscall.EINVAL 185 } 186 n, oobn, err = c.writeMsg(b, oob, addr) 187 if err != nil { 188 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err} 189 } 190 return 191 } 192 193 func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} } 194 195 // DialUDP acts like Dial for UDP networks. 196 // 197 // The network must be a UDP network name; see func Dial for details. 198 // 199 // If laddr is nil, a local address is automatically chosen. 200 // If the IP field of raddr is nil or an unspecified IP address, the 201 // local system is assumed. 202 func DialUDP(network string, laddr, raddr *UDPAddr) (*UDPConn, error) { 203 switch network { 204 case "udp", "udp4", "udp6": 205 default: 206 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)} 207 } 208 if raddr == nil { 209 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress} 210 } 211 sd := &sysDialer{network: network, address: raddr.String()} 212 c, err := sd.dialUDP(context.Background(), 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 // ListenUDP acts like ListenPacket for UDP networks. 220 // 221 // The network must be a UDP network name; see func Dial for details. 222 // 223 // If the IP field of laddr is nil or an unspecified IP address, 224 // ListenUDP listens on all available IP addresses of the local system 225 // except multicast IP addresses. 226 // If the Port field of laddr is 0, a port number is automatically 227 // chosen. 228 func ListenUDP(network string, laddr *UDPAddr) (*UDPConn, error) { 229 switch network { 230 case "udp", "udp4", "udp6": 231 default: 232 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)} 233 } 234 if laddr == nil { 235 laddr = &UDPAddr{} 236 } 237 sl := &sysListener{network: network, address: laddr.String()} 238 c, err := sl.listenUDP(context.Background(), laddr) 239 if err != nil { 240 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err} 241 } 242 return c, nil 243 } 244 245 // ListenMulticastUDP acts like ListenPacket for UDP networks but 246 // takes a group address on a specific network interface. 247 // 248 // The network must be a UDP network name; see func Dial for details. 249 // 250 // ListenMulticastUDP listens on all available IP addresses of the 251 // local system including the group, multicast IP address. 252 // If ifi is nil, ListenMulticastUDP uses the system-assigned 253 // multicast interface, although this is not recommended because the 254 // assignment depends on platforms and sometimes it might require 255 // routing configuration. 256 // If the Port field of gaddr is 0, a port number is automatically 257 // chosen. 258 // 259 // ListenMulticastUDP is just for convenience of simple, small 260 // applications. There are golang.org/x/net/ipv4 and 261 // golang.org/x/net/ipv6 packages for general purpose uses. 262 // 263 // Note that ListenMulticastUDP will set the IP_MULTICAST_LOOP socket option 264 // to 0 under IPPROTO_IP, to disable loopback of multicast packets. 265 func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) { 266 switch network { 267 case "udp", "udp4", "udp6": 268 default: 269 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)} 270 } 271 if gaddr == nil || gaddr.IP == nil { 272 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress} 273 } 274 sl := &sysListener{network: network, address: gaddr.String()} 275 c, err := sl.listenMulticastUDP(context.Background(), ifi, gaddr) 276 if err != nil { 277 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err} 278 } 279 return c, nil 280 }