Fix parsing of IPv4 source prefix.

An empty IPv4 source prefix is represented by a v4mapped
default prefix.  This was not always the case.  Thanks to
Fabian Blaese.

babeld.c

@@ -1081,12 +1081,10 @@ dump_route(FILE *out, struct babel_route *route)
         snprintf(channels + j, 100 - j, ")");
     }
 
-    fprintf(out, "%s%s%s metric %d (%d) refmetric %d id %s "
+    fprintf(out, "%s from %s metric %d (%d) refmetric %d id %s "
             "seqno %d%s age %d via %s neigh %s%s%s%s\n",
             format_prefix(route->src->prefix, route->src->plen),
-            route->src->src_plen > 0 ? " from " : "",
-            route->src->src_plen > 0 ?
-            format_prefix(route->src->src_prefix, route->src->src_plen) : "",
+            format_prefix(route->src->src_prefix, route->src->src_plen),
             route_metric(route), route_smoothed_metric(route), route->refmetric,
             format_eui64(route->src->id),
             (int)route->seqno,
@@ -1103,11 +1101,9 @@ dump_route(FILE *out, struct babel_route *route)
 static void
 dump_xroute(FILE *out, struct xroute *xroute)
 {
-    fprintf(out, "%s%s%s metric %d (exported)\n",
+    fprintf(out, "%s from %s metric %d (exported)\n",
             format_prefix(xroute->prefix, xroute->plen),
-            xroute->src_plen > 0 ? " from " : "",
-            xroute->src_plen > 0 ?
-            format_prefix(xroute->src_prefix, xroute->src_plen) : "",
+            format_prefix(xroute->src_prefix, xroute->src_plen),
             xroute->metric);
 }
 

message.c

@@ -127,6 +127,7 @@ parse_update_subtlv(struct interface *ifp, int metric, int ae,
 {
     int type, len, i = 0;
     int channels_len;
+    int have_src_prefix = 0;
 
     /* This will be overwritten if there's a DIVERSITY_HOPS sub-TLV. */
     if(*channels_len_return < 1 || (ifp->flags & IF_FARAWAY)) {
@@ -142,8 +143,6 @@ parse_update_subtlv(struct interface *ifp, int metric, int ae,
         }
     }
 
-    *src_plen = 0;
-
     while(i < alen) {
         type = a[i];
         if(type == SUBTLV_PAD1) {
@@ -168,15 +167,17 @@ parse_update_subtlv(struct interface *ifp, int metric, int ae,
                 goto fail;
             if(a[i + 2] == 0)   /* source prefix cannot be default */
                 goto fail;
-            if(*src_plen != 0)  /* source prefix can only be specified once */
+            if(have_src_prefix != 0) /* source prefix can only appear once */
                 goto fail;
-            *src_plen = a[i + 2];
-            rc = network_prefix(ae, *src_plen, 0, a + i + 3, NULL,
+            rc = network_prefix(ae, a[i + 2], 0, a + i + 3, NULL,
                                 len - 1, src_prefix);
             if(rc < 0)
                 goto fail;
             if(ae == 1)
-                (*src_plen) += 96;
+                *src_plen = a[i + 2] + 96;
+            else
+                *src_plen = a[i + 2];
+            have_src_prefix = 1;
         } else {
             debugf("Received unknown%s Update sub-TLV %d.\n",
                    (type & 0x80) != 0 ? " mandatory" : "", type);
@@ -309,8 +310,7 @@ parse_request_subtlv(int ae, const unsigned char *a, int alen,
                      unsigned char *src_prefix, unsigned char *src_plen)
 {
     int type, len, i = 0;
-
-    *src_plen = 0;
+    int have_src_prefix = 0;
 
     while(i < alen) {
         type = a[0];
@@ -334,15 +334,17 @@ parse_request_subtlv(int ae, const unsigned char *a, int alen,
                 goto fail;
             if(a[i + 2] == 0)
                 goto fail;
-            if(*src_plen != 0)
+            if(have_src_prefix != 0)
                 goto fail;
-            *src_plen = a[i + 2];
-            rc = network_prefix(ae, *src_plen, 0, a + i + 3, NULL,
+            rc = network_prefix(ae, a[i + 2], 0, a + i + 3, NULL,
                                 len - 1, src_prefix);
             if(rc < 0)
                 goto fail;
             if(ae == 1)
-                (*src_plen) += 96;
+                *src_plen = a[i + 2] + 96;
+            else
+                *src_plen = a[i + 2];
+            have_src_prefix = 1;
         } else {
             debugf("Received unknown%s Route Request sub-TLV %d.\n",
                    ((type & 0x80) != 0) ? " mandatory" : "", type);

xroute.c

@@ -276,8 +276,13 @@ filter_address(struct kernel_addr *addr, void *data) {
         return 0;
 
     route = &routes[*found];
+    memset(route, 0, sizeof(struct kernel_route));
     memcpy(route->prefix, addr->addr.s6_addr, 16);
     route->plen = 128;
+    if(v4mapped(route->prefix)) {
+        memcpy(route->src_prefix, v4prefix, 16);
+        route->src_plen = 96;
+    }
     route->metric = 0;
     route->ifindex = addr->ifindex;
     route->proto = RTPROT_BABEL_LOCAL;