49 lines
1 KiB
C
49 lines
1 KiB
C
#include <sys/socket.h>
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#include <netinet/in.h>
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#include <netinet/tcp.h>
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#include <arpa/inet.h>
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#include <inttypes.h>
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#include <errno.h>
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#include <stdio.h>
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#include <unistd.h>
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int main(int argc, char *argv[]) {
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int s;
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struct sockaddr_storage sa;
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socklen_t salen;
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uint16_t port;
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if ((s = socket(PF_INET6, SOCK_STREAM, 0)) < 0) {
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if (errno == EAFNOSUPPORT)
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s = socket(PF_INET, SOCK_STREAM, 0);
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if (s < 0) {
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perror("socket()");
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return 1;
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}
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}
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if (listen(s, 2) < 0) {
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perror("listen()");
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return 2;
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}
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salen = sizeof(sa);
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if (getsockname(s, (struct sockaddr*) &sa, &salen) < 0) {
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perror("getsockname()");
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return 3;
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}
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if (((struct sockaddr*) &sa)->sa_family == AF_INET)
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port = ((struct sockaddr_in*) &sa)->sin_port;
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else
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port = ((struct sockaddr_in6*) &sa)->sin6_port;
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printf("Selected port number %u\n", ntohs(port));
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/* ... hic sunt leones ... */
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sleep(60);
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return 0;
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}
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