[PATCH] ifconfig: Support prefix length.

[Samuel Thibault]

Prefix lengths are much more convenient, support them as an alternative
to passing -m separately from -A.

* ifconfig/options.c (parse_opt): Detect prefix length, and in such a
case, call parse_opt_set_netmask.

Index: inetutils-2.3/ifconfig/options.c
===================================================================
--- inetutils-2.3.orig/ifconfig/options.c
+++ inetutils-2.3/ifconfig/options.c
@@ -547,8 +547,29 @@ parse_opt (int key, char *arg, struct ar
       break;
 
     case 'A':          /* Interface address.  */
-      parse_opt_set_address (ifp, arg);
-      break;
+      {
+       char *netlen = strchr (arg, '/');
+
+       if (netlen)
+         {
+           char *end, *str;
+           unsigned n;
+           struct in_addr addr;
+
+           *netlen++ = 0;
+
+           n = strtol (netlen, &end, 10);
+           if (end == netlen)
+             error (EXIT_FAILURE, 0, "Wrong netmask length %s", netlen);
+
+           addr.s_addr = htonl (INADDR_BROADCAST << (32-n));
+           str = strdup (inet_ntoa (addr));
+           parse_opt_set_netmask (ifp, str);
+         }
+
+       parse_opt_set_address (ifp, arg);
+       break;
+      }
 
     case 'm':          /* Interface netmask.  */
       parse_opt_set_netmask (ifp, arg);