forked from avahi/avahi
-
Notifications
You must be signed in to change notification settings - Fork 0
/
socket-auto-port.c
49 lines (39 loc) · 1.04 KB
/
socket-auto-port.c
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
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <inttypes.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
int main(int argc, char *argv[]) {
int s;
struct sockaddr_storage sa;
socklen_t salen;
uint16_t port;
if ((s = socket(PF_INET6, SOCK_STREAM, 0)) < 0) {
if (errno == EAFNOSUPPORT)
s = socket(PF_INET, SOCK_STREAM, 0);
if (s < 0) {
perror("socket()");
return 1;
}
}
if (listen(s, 2) < 0) {
perror("listen()");
return 2;
}
salen = sizeof(sa);
if (getsockname(s, (struct sockaddr*) &sa, &salen) < 0) {
perror("getsockname()");
return 3;
}
if (((struct sockaddr*) &sa)->sa_family == AF_INET)
port = ((struct sockaddr_in*) &sa)->sin_port;
else
port = ((struct sockaddr_in6*) &sa)->sin6_port;
printf("Selected port number %u\n", ntohs(port));
/* ... hic sunt leones ... */
sleep(60);
return 0;
}