1gen_udp(3) Erlang Module Definition gen_udp(3)
2
6 gen_udp - Interface to UDP sockets.
7
9 This module provides functions for communicating with sockets using the
10 UDP protocol.
11
13 option() =
14 {active, true | false | once | -32768..32767} |
15 {add_membership, {inet:ip_address(), inet:ip_address()}} |
16 {broadcast, boolean()} |
17 {buffer, integer() >= 0} |
18 {deliver, port | term} |
19 {dontroute, boolean()} |
20 {drop_membership, {inet:ip_address(), inet:ip_address()}} |
21 {header, integer() >= 0} |
22 {high_msgq_watermark, integer() >= 1} |
23 {low_msgq_watermark, integer() >= 1} |
24 {mode, list | binary} |
25 list | binary |
26 {multicast_if, inet:ip_address()} |
27 {multicast_loop, boolean()} |
28 {multicast_ttl, integer() >= 0} |
29 {priority, integer() >= 0} |
30 {raw,
31 Protocol :: integer() >= 0,
32 OptionNum :: integer() >= 0,
33 ValueBin :: binary()} |
34 {read_packets, integer() >= 0} |
35 {recbuf, integer() >= 0} |
36 {reuseaddr, boolean()} |
37 {sndbuf, integer() >= 0} |
38 {tos, integer() >= 0} |
39 {tclass, integer() >= 0} |
40 {ttl, integer() >= 0} |
41 {recvtos, boolean()} |
42 {recvtclass, boolean()} |
43 {recvttl, boolean()} |
44 {ipv6_v6only, boolean()}
45 option_name() =
47 active | broadcast | buffer | deliver | dontroute | header |
48 high_msgq_watermark | low_msgq_watermark | mode |
49 multicast_if | multicast_loop | multicast_ttl | priority |
50 {raw,
51 Protocol :: integer() >= 0,
52 OptionNum :: integer() >= 0,
53 ValueSpec ::
54 (ValueSize :: integer() >= 0) | (ValueBin :: binary())} |
55 read_packets | recbuf | reuseaddr | sndbuf | tos | tclass |
56 ttl | recvtos | recvtclass | recvttl | pktoptions |
57 ipv6_v6only
58 socket()
60 As returned by open/1,2.
62
64 close(Socket) -> ok
65 Types:
67 Socket = socket()
69 Closes a UDP socket.
71 controlling_process(Socket, Pid) -> ok | {error, Reason}
73 Types:
75 Socket = socket()
77 Pid = pid()
78 Reason = closed | not_owner | badarg | inet:posix()
79 Assigns a new controlling process Pid to Socket. The controlling
81 process is the process that receives messages from the socket.
82 If called by any other process than the current controlling
83 process, {error, not_owner} is returned. If the process identi‐
84 fied by Pid is not an existing local pid, {error, badarg} is
85 returned. {error, badarg} may also be returned in some cases
86 when Socket is closed during the execution of this function.
87 open(Port) -> {ok, Socket} | {error, Reason}
89 open(Port, Opts) -> {ok, Socket} | {error, Reason}
91 Types:
93 Port = inet:port_number()
95 Opts = [Option]
96 Option =
97 {ip, inet:socket_address()} |
98 {fd, integer() >= 0} |
99 {ifaddr, inet:socket_address()} |
100 inet:address_family() |
101 {port, inet:port_number()} |
102 {netns, file:filename_all()} |
103 {bind_to_device, binary()} |
104 option()
105 Socket = socket()
106 Reason = system_limit | inet:posix()
107 Associates a UDP port number (Port) with the calling process.
109 The following options are available:
111 list:
113 Received Packet is delivered as a list.
114 binary:
116 Received Packet is delivered as a binary.
117 {ip, Address}:
119 If the host has many network interfaces, this option speci‐
120 fies which one to use.
121 {ifaddr, Address}:
123 Same as {ip, Address}. If the host has many network inter‐
124 faces, this option specifies which one to use.
125 {fd, integer() >= 0}:
127 If a socket has somehow been opened without using gen_udp,
128 use this option to pass the file descriptor for it. If Port
129 is not set to 0 and/or {ip, ip_address()} is combined with
130 this option, the fd is bound to the specified interface and
131 port after it is being opened. If these options are not
132 specified, it is assumed that the fd is already bound appro‐
133 priately.
134 inet6:
136 Sets up the socket for IPv6.
137 inet:
139 Sets up the socket for IPv4.
140 local:
142 Sets up a Unix Domain Socket. See inet:local_address()
143 {udp_module, module()}:
145 Overrides which callback module is used. Defaults to
146 inet_udp for IPv4 and inet6_udp for IPv6.
147 {multicast_if, Address}:
149 Sets the local device for a multicast socket.
150 {multicast_loop, true | false}:
152 When true, sent multicast packets are looped back to the
153 local sockets.
154 {multicast_ttl, Integer}:
156 Option multicast_ttl changes the time-to-live (TTL) for out‐
157 going multicast datagrams to control the scope of the multi‐
158 casts.
159 Datagrams with a TTL of 1 are not forwarded beyond the local
161 network. Defaults to 1.
162 {add_membership, {MultiAddress, InterfaceAddress}}:
164 Joins a multicast group.
165 {drop_membership, {MultiAddress, InterfaceAddress}}:
167 Leaves a multicast group.
168 Opt:
170 See inet:setopts/2.
171 The returned socket Socket is used to send packets from this
173 port with send/4. When UDP packets arrive at the opened port, if
174 the socket is in an active mode, the packets are delivered as
175 messages to the controlling process:
176 {udp, Socket, IP, InPortNo, Packet} % Without ancillary data
178 {udp, Socket, IP, InPortNo, AncData, Packet} % With ancillary data
179 The message contains an AncData field if any of the socket
182 options recvtos, recvtclass or recvttl are active, otherwise it
183 does not.
184 If the socket is not in an active mode, data can be retrieved
186 through the recv/2,3 calls. Notice that arriving UDP packets
187 that are longer than the receive buffer option specifies can be
188 truncated without warning.
189 When a socket in {active, N} mode (see inet:setopts/2 for
191 details), transitions to passive ({active, false}) mode, the
192 controlling process is notified by a message of the following
193 form:
194 {udp_passive, Socket}
196 IP and InPortNo define the address from which Packet comes.
198 Packet is a list of bytes if option list is specified. Packet is
199 a binary if option binary is specified.
200 Default value for the receive buffer option is {recbuf, 8192}.
202 If Port == 0, the underlying OS assigns a free UDP port, use
204 inet:port/1 to retrieve it.
205 recv(Socket, Length) -> {ok, RecvData} | {error, Reason}
207 recv(Socket, Length, Timeout) -> {ok, RecvData} | {error, Reason}
209 Types:
211 Socket = socket()
213 Length = integer() >= 0
214 Timeout = timeout()
215 RecvData =
216 {Address, Port, Packet} | {Address, Port, AncData,
217 Packet}
218 Address = inet:ip_address() | inet:returned_non_ip_address()
219 Port = inet:port_number()
220 AncData = inet:ancillary_data()
221 Packet = string() | binary()
222 Reason = not_owner | timeout | inet:posix()
223 Receives a packet from a socket in passive mode. Optional param‐
225 eter Timeout specifies a time-out in milliseconds. Defaults to
226 infinity.
227 If any of the socket options recvtos, recvtclass or recvttl are
229 active, the RecvData tuple contains an AncData field, otherwise
230 it does not.
231 send(Socket, Destination, Packet) -> ok | {error, Reason}
233 Types:
235 Socket = socket()
237 Destination =
238 {inet:ip_address(), inet:port_number()} |
239 inet:family_address()
240 Packet = iodata()
241 Reason = not_owner | inet:posix()
242 Sends a packet to the specified Destination.
244 This function is equivalent to send(Socket, Destination, [],
246 Packet).
247 send(Socket, Host, Port, Packet) -> ok | {error, Reason}
249 Types:
251 Socket = socket()
253 Host = inet:hostname() | inet:ip_address()
254 Port = inet:port_number() | atom()
255 Packet = iodata()
256 Reason = not_owner | inet:posix()
257 Sends a packet to the specified Host and Port.
259 This clause is equivalent to send(Socket, Host, Port, [],
261 Packet).
262 send(Socket, Destination, AncData, Packet) -> ok | {error, Reason}
264 Types:
266 Socket = socket()
268 Destination =
269 {inet:ip_address(), inet:port_number()} |
270 inet:family_address()
271 AncData = inet:ancillary_data()
272 Packet = iodata()
273 Reason = not_owner | inet:posix()
274 Sends a packet to the specified Destination with ancillary data
276 AncData.
277 Note:
279 The ancillary data AncData contains options that for this single
280 message override the default options for the socket, an opera‐
281 tion that may not be supported on all platforms, and if so
282 return {error, einval}. Using more than one of an ancillary data
283 item type may also not be supported. AncData =:= [] is always
284 supported.
285 send(Socket, Destination, PortZero, Packet) ->
288 ok | {error, Reason}
289 Types:
291 Socket = socket()
293 Destination =
294 {inet:ip_address(), inet:port_number()} |
295 inet:family_address()
296 PortZero = inet:port_number()
297 Packet = iodata()
298 Reason = not_owner | inet:posix()
299 Sends a packet to the specified Destination. Since Destination
301 is complete, PortZero is redundant and has to be 0.
302 This is a legacy clause mostly for Destination = {local, Binary}
304 where PortZero is superfluous. It is equivalent to send(Socket,
305 Destination, [], Packet), the clause right above here.
306 send(Socket, Host, Port, AncData, Packet) -> ok | {error, Reason}
308 Types:
310 Socket = socket()
312 Host =
313 inet:hostname() | inet:ip_address() |
314 inet:local_address()
315 Port = inet:port_number() | atom()
316 AncData = inet:ancillary_data()
317 Packet = iodata()
318 Reason = not_owner | inet:posix()
319 Sends a packet to the specified Host and Port, with ancillary
321 data AncData.
322 Argument Host can be a hostname or a socket address, and Port
324 can be a port number or a service name atom. These are resolved
325 into a Destination and after that this function is equivalent to
326 send(Socket, Destination, AncData, Packet), read there about
327 ancillary data.
328Ericsson AB kernel 6.5.2 gen_udp(3)