Implement if_nametoindex & if_indextoname

include/net/if.h

@@ -218,6 +218,10 @@ struct sockaddr_hw {
 	unsigned char	shw_addr[8];	/* address */
 };
 
+/* Convert an interface name to an index, and vice versa.  */
+extern unsigned short if_nametoindex (const char *__ifname) __THROW;
+extern char *if_indextoname (unsigned short __ifindex, char __ifname[IF_NAMESIZE]) __THROW;
+
 __END_DECLS
 
 #endif /* _NET_IF_H */

socket/SRCFILES

@@ -38,6 +38,8 @@ SRCFILES = \
 	hstrerror.c \
 	hton.c \
 	ident_sock.c \
+	if_indextoname.c \
+	if_nametoindex.c \
 	inet_addr.c \
 	inet_lnaof.c \
 	inet_makeaddr.c \

socket/if_indextoname.c

@@ -0,0 +1,29 @@
+#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+__typeof__(if_indextoname) __if_indextoname;
+
+char *
+__if_indextoname(unsigned short index, char name[IF_NAMESIZE])
+{
+	struct ifreq ifr;
+	int fd, r;
+
+	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0){ 
+        __set_errno (ENXIO);
+        return NULL;
+    }
+	ifr.ifr_ifindex = index;
+	r = ioctl(fd, SIOCGIFNAME_ETH, &ifr);
+	close(fd);
+    if(!r){
+        return strncpy(name, ifr.ifr_name, IF_NAMESIZE);
+    }
+    __set_errno (ENXIO);
+	return NULL;
+}
+weak_alias (__if_indextoname, if_indextoname)

socket/if_nametoindex.c

@@ -0,0 +1,29 @@
+#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+__typeof__(if_nametoindex) __if_nametoindex;
+
+unsigned short 
+if_nametoindex(const char *name)
+{
+	struct ifreq ifr;
+	int fd, r;
+
+	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+        __set_errno (ENODEV);
+        return 0;
+    }
+	strlcpy(ifr.ifr_name, name, sizeof ifr.ifr_name);
+	r = ioctl(fd, SIOCGIFINDEX, &ifr);
+	close(fd);
+    if(!r){
+        return ifr.ifr_ifindex;
+    }
+    __set_errno (ENODEV);
+	return 0;
+}
+weak_alias (__if_nametoindex, if_nametoindex)