ifaddr initial import

src/getifaddr.c

@@ -0,0 +1,53 @@
+#define _GNU_SOURCE     /* To get defns of NI_MAXSERV and NI_MAXHOST */
+#include <ifaddrs.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <ifaddrs.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/if_link.h>
+#include <string.h>
+
+char * get_if_addr(char *ifname)
+{
+
+  struct ifaddrs * list, * plist;
+  int family, s;
+
+	char host[NI_MAXHOST];
+  char *result;
+  if (getifaddrs (&list)==-1)
+  {
+    fprintf(stderr, "no info");
+    return NULL;
+  }
+  plist = list;
+  while (plist!=NULL)
+  {
+    if (strcmp(plist->ifa_name,ifname)==0) 
+		{
+      family = plist->ifa_addr->sa_family;
+      if (family == AF_INET || family == AF_INET6) {
+                   s = getnameinfo(plist->ifa_addr,
+                           (family == AF_INET) ? sizeof(struct sockaddr_in) :
+                                                 sizeof(struct sockaddr_in6),
+                           host, NI_MAXHOST,
+                           NULL, 0, NI_NUMERICHOST);
+                   if (s != 0) {
+                       fprintf(stderr, "getnameinfo() failed: %s\n", gai_strerror(s));
+                       exit(EXIT_FAILURE);
+                   }
+                   result = malloc(strlen(host)+1);
+                   strcpy(result,host);
+                   freeifaddrs (list);
+                   return result;
+               }
+    }
+    plist = plist->ifa_next;
+  }
+  freeifaddrs (list);
+  return NULL;
+
+}