i3status/src/print_ip_addr.c

67 lines
1.6 KiB
C

// vim:ts=4:sw=4:expandtab
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <net/if.h>
#include "i3status.h"
/*
* Return the IP address for the given interface or "no IP" if the
* interface is up and running but hasn't got an IP address yet
*
*/
const char *get_ip_addr(const char *interface) {
static char part[512];
socklen_t len = sizeof(struct sockaddr_in);
memset(part, 0, sizeof(part));
struct ifaddrs *ifaddr, *addrp;
bool found = false;
getifaddrs(&ifaddr);
if (ifaddr == NULL)
return NULL;
/* Skip until we are at the AF_INET address of interface */
for (addrp = ifaddr;
(addrp != NULL &&
(strcmp(addrp->ifa_name, interface) != 0 ||
addrp->ifa_addr == NULL ||
addrp->ifa_addr->sa_family != AF_INET));
addrp = addrp->ifa_next) {
/* Check if the interface is down */
if (strcmp(addrp->ifa_name, interface) != 0)
continue;
found = true;
if ((addrp->ifa_flags & IFF_RUNNING) == 0) {
freeifaddrs(ifaddr);
return NULL;
}
}
if (addrp == NULL) {
freeifaddrs(ifaddr);
return (found ? "no IP" : NULL);
}
int ret;
if ((ret = getnameinfo(addrp->ifa_addr, len, part, sizeof(part), NULL, 0, NI_NUMERICHOST)) != 0) {
fprintf(stderr, "i3status: getnameinfo(): %s\n", gai_strerror(ret));
freeifaddrs(ifaddr);
return "no IP";
}
freeifaddrs(ifaddr);
return part;
}