udp_pair

udp_pair

A very simple C object that wraps the BSD socket API to provide a UDP socket pair abstraction. Basically say you have two known endpoints that need to talk to each other over UDP. You know the port you are receiving on and the address/port of the other end point. You can define a UDP pair object that represents your end point and simply send/receive for that set up.

If you look at the code you'll see it's mostly a toy because performing such a set up is very straightforward (bind(), connect(), send(), recv()), but it can be a handy abstraction for those who are not so socket savvy.

Example

struct udp_pair* pair = udp_pair_create(recv_port, dest_ip4, dest_port);
char buf[512];
while (1) {
  ssize_t bytes_recvd = 0;
  udp_pair_recv(pair, (void*)buf, sizeof(buf), &bytes_recvd);
  if (bytes_recvd > 0) {
    udp_pair_send(pair, (void*)buf, bytes_recvd, NULL);
  }
}
udp_pair_free(pair);

The example sources are more verbose than this snippet due to error checking. There are three examples provided:

• example/echo_server.c
• example/spam_hello_world.c
• bin/udpcat.c

Building

The usual CMake/Make dance.

mkdir build
cd build
cmake ..
make

udpcat Example

Once built you can get two udpcat processes to talk to each other pretty simply. Just open up one session as udpcat 12345 127.0.0.1 12346 and the other as udpcat 12346 127.0.0.1 12345. Any lines entered at the prompt (stdin input) will be sent to the other udpcat process and printed to stdout.