1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package net
import (
"context"
"syscall"
)
// BUG(mikio): On NaCl, Plan 9 and Windows, the ReadMsgUDP and
// WriteMsgUDP methods of UDPConn are not implemented.
// BUG(mikio): On Windows, the File method of UDPConn is not
// implemented.
// BUG(mikio): On NaCl, the ListenMulticastUDP function is not
// implemented.
// UDPAddr represents the address of a UDP end point.
type UDPAddr struct {
IP IP
Port int
Zone string // IPv6 scoped addressing zone
}
// Network returns the address's network name, "udp".
func (a *UDPAddr) Network() string { return "udp" }
func (a *UDPAddr) String() string {
if a == nil {
return "<nil>"
}
ip := ipEmptyString(a.IP)
if a.Zone != "" {
return JoinHostPort(ip+"%"+a.Zone, itoa(a.Port))
}
return JoinHostPort(ip, itoa(a.Port))
}
func (a *UDPAddr) isWildcard() bool {
if a == nil || a.IP == nil {
return true
}
return a.IP.IsUnspecified()
}
func (a *UDPAddr) opAddr() Addr {
if a == nil {
return nil
}
return a
}
// ResolveUDPAddr parses addr as a UDP address of the form "host:port"
// or "[ipv6-host%zone]:port" and resolves a pair of domain name and
// port name on the network net, which must be "udp", "udp4" or
// "udp6". A literal address or host name for IPv6 must be enclosed
// in square brackets, as in "[::1]:80", "[ipv6-host]:http" or
// "[ipv6-host%zone]:80".
//
// Resolving a hostname is not recommended because this returns at most
// one of its IP addresses.
func ResolveUDPAddr(net, addr string) (*UDPAddr, error) {
switch net {
case "udp", "udp4", "udp6":
case "": // a hint wildcard for Go 1.0 undocumented behavior
net = "udp"
default:
return nil, UnknownNetworkError(net)
}
addrs, err := DefaultResolver.internetAddrList(context.Background(), net, addr)
if err != nil {
return nil, err
}
return addrs.first(isIPv4).(*UDPAddr), nil
}
// UDPConn is the implementation of the Conn and PacketConn interfaces
// for UDP network connections.
type UDPConn struct {
conn
}
// ReadFromUDP reads a UDP packet from c, copying the payload into b.
// It returns the number of bytes copied into b and the return address
// that was on the packet.
//
// ReadFromUDP can be made to time out and return an error with
// Timeout() == true after a fixed time limit; see SetDeadline and
// SetReadDeadline.
func (c *UDPConn) ReadFromUDP(b []byte) (int, *UDPAddr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, addr, err := c.readFrom(b)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
return n, addr, err
}
// ReadFrom implements the PacketConn ReadFrom method.
func (c *UDPConn) ReadFrom(b []byte) (int, Addr, error) {
if !c.ok() {
return 0, nil, syscall.EINVAL
}
n, addr, err := c.readFrom(b)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
if addr == nil {
return n, nil, err
}
return n, addr, err
}
// ReadMsgUDP reads a packet from c, copying the payload into b and
// the associated out-of-band data into oob. It returns the number
// of bytes copied into b, the number of bytes copied into oob, the
// flags that were set on the packet and the source address of the
// packet.
func (c *UDPConn) ReadMsgUDP(b, oob []byte) (n, oobn, flags int, addr *UDPAddr, err error) {
if !c.ok() {
return 0, 0, 0, nil, syscall.EINVAL
}
n, oobn, flags, addr, err = c.readMsg(b, oob)
if err != nil {
err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
}
return
}
// WriteToUDP writes a UDP packet to addr via c, copying the payload
// from b.
//
// WriteToUDP can be made to time out and return an error with
// Timeout() == true after a fixed time limit; see SetDeadline and
// SetWriteDeadline. On packet-oriented connections, write timeouts
// are rare.
func (c *UDPConn) WriteToUDP(b []byte, addr *UDPAddr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
n, err := c.writeTo(b, addr)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return n, err
}
// WriteTo implements the PacketConn WriteTo method.
func (c *UDPConn) WriteTo(b []byte, addr Addr) (int, error) {
if !c.ok() {
return 0, syscall.EINVAL
}
a, ok := addr.(*UDPAddr)
if !ok {
return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
}
n, err := c.writeTo(b, a)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
}
return n, err
}
// WriteMsgUDP writes a packet to addr via c if c isn't connected, or
// to c's remote destination address if c is connected (in which case
// addr must be nil). The payload is copied from b and the associated
// out-of-band data is copied from oob. It returns the number of
// payload and out-of-band bytes written.
func (c *UDPConn) WriteMsgUDP(b, oob []byte, addr *UDPAddr) (n, oobn int, err error) {
if !c.ok() {
return 0, 0, syscall.EINVAL
}
n, oobn, err = c.writeMsg(b, oob, addr)
if err != nil {
err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
}
return
}
func newUDPConn(fd *netFD) *UDPConn { return &UDPConn{conn{fd}} }
// DialUDP connects to the remote address raddr on the network net,
// which must be "udp", "udp4", or "udp6". If laddr is not nil, it is
// used as the local address for the connection.
func DialUDP(net string, laddr, raddr *UDPAddr) (*UDPConn, error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)}
}
if raddr == nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
}
c, err := dialUDP(context.Background(), net, laddr, raddr)
if err != nil {
return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
}
return c, nil
}
// ListenUDP listens for incoming UDP packets addressed to the local
// address laddr. Net must be "udp", "udp4", or "udp6". If laddr has
// a port of 0, ListenUDP will choose an available port.
// The LocalAddr method of the returned UDPConn can be used to
// discover the port. The returned connection's ReadFrom and WriteTo
// methods can be used to receive and send UDP packets with per-packet
// addressing.
func ListenUDP(net string, laddr *UDPAddr) (*UDPConn, error) {
switch net {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
}
if laddr == nil {
laddr = &UDPAddr{}
}
c, err := listenUDP(context.Background(), net, laddr)
if err != nil {
return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: err}
}
return c, nil
}
// ListenMulticastUDP listens for incoming multicast UDP packets
// addressed to the group address gaddr on the interface ifi.
// Network must be "udp", "udp4" or "udp6".
// ListenMulticastUDP uses the system-assigned multicast interface
// when ifi is nil, although this is not recommended because the
// assignment depends on platforms and sometimes it might require
// routing configuration.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
func ListenMulticastUDP(network string, ifi *Interface, gaddr *UDPAddr) (*UDPConn, error) {
switch network {
case "udp", "udp4", "udp6":
default:
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: UnknownNetworkError(network)}
}
if gaddr == nil || gaddr.IP == nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: errMissingAddress}
}
c, err := listenMulticastUDP(context.Background(), network, ifi, gaddr)
if err != nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: gaddr.opAddr(), Err: err}
}
return c, nil
}
|