This is a short example to retrieve an ip address from an interface in Linux. It is typically used to be able to bind a port to a specific address on a machine.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
int main(int argc, char **argv) {
int sock = socket(PF_INET, SOCK_DGRAM, 0);
struct ifreq req;
if (argc < 2) {
fprintf(stderr, "Usage: %s <interfacename>\n", argv[0]);
exit(EXIT_FAILURE);
}
if (sock < 0) {
perror("socket");
exit(EXIT_FAILURE);
}
memset(&req, 0, sizeof(req));
strncpy(req.ifr_name, argv[1], IF_NAMESIZE - 1);
if (ioctl(sock, SIOCGIFADDR, &req) < 0) {
perror("ioctl");
exit(EXIT_FAILURE);
}
printf("%s\n", inet_ntoa(((struct sockaddr_in *)&req.ifr_addr)->sin_addr));
close(sock);
exit(EXIT_SUCCESS);
return 0;
}
Did You find this page useful?
Yes
No
Last Modified: 21 February 2017
Releated Posts
2017-04-25 - Linux Programming - Signals the easy way
2017-03-01 - Shooting yourself in the head with threads
2013-02-16 - C - Some simple examples of using strcat
2012-11-03 - C - How to override malloc / free
2012-08-09 - C++ - Check an IP Address is in a IP Mask
2012-06-16 - CPP - Using gperf
2012-04-05 - Using gdb to debug a core file
2012-03-15 - C - Is the stdin a tty
2012-03-13 - C - Converting from char / string to int using atoi
2012-03-08 - C - UDP Socket example
2012-02-20 - C - Get home dir location in linux
2012-02-17 - C - IP address validation
2012-02-15 - C - Get current ip address of an interface
2012-02-10 - Using asprintf instead of sprintf or snprintf
2012-01-31 - C - Example of how to overwrite argv
2012-01-30 - C - The string reverse
2012-01-27 - C - Palindrome
2012-01-26 - C - Example of using popen
2011-12-28 - C - gethostbyname example
2011-12-11 - C - Linux get mac address from interface
2011-02-10 - CSharp - Wake on Lan (WOL) Packet