Use standard v4mapped encoding for source prefixes.

interface.h

@@ -25,7 +25,7 @@ struct buffered_update {
     unsigned char prefix[16];
     unsigned char src_prefix[16];
     unsigned char plen;
-    unsigned char src_plen; /* 0 <=> no src prefix */
+    unsigned char src_plen;
     unsigned char pad[2];
 };
 

kernel.h

@@ -29,7 +29,7 @@ struct kernel_route {
     unsigned char prefix[16];
     int plen;
     unsigned char src_prefix[16];
-    int src_plen; /* no source prefix <=> src_plen == 0 */
+    int src_plen;
     int metric;
     unsigned int ifindex;
     int proto;

kernel_netlink.c

@@ -955,12 +955,12 @@ kernel_route(int operation, int table,
     /* Check that the protocol family is consistent. */
     if(plen >= 96 && v4mapped(dest)) {
         if(!v4mapped(gate) ||
-           (src_plen > 0 && (!v4mapped(src) || src_plen < 96))) {
+           !v4mapped(src)) {
             errno = EINVAL;
             return -1;
         }
     } else {
-        if(v4mapped(gate)|| (src_plen > 0 && v4mapped(src))) {
+        if(v4mapped(gate) || v4mapped(src)) {
             errno = EINVAL;
             return -1;
         }
@@ -995,7 +995,7 @@ kernel_route(int operation, int table,
 
 
     ipv4 = v4mapped(gate);
-    use_src = (src_plen != 0 && kernel_disambiguate(ipv4));
+    use_src = (!is_default(src, src_plen) && kernel_disambiguate(ipv4));
 
     kdebugf("kernel_route: %s %s from %s "
             "table %d metric %d dev %d nexthop %s\n",
@@ -1096,6 +1096,7 @@ parse_kernel_route_rta(struct rtmsg *rtm, int len, struct kernel_route *route)
         /* if RTA_DST is not a TLV, that's a default destination */
         const unsigned char zeroes[4] = {0, 0, 0, 0};
         v4tov6(route->prefix, zeroes);
+        v4tov6(route->src_prefix, zeroes);
         route->plen = 96;
     }
     route->proto = rtm->rtm_protocol;

kernel_socket.c

@@ -424,7 +424,7 @@ kernel_route(int operation, int table,
             0x00, 0x00, 0x00, 0x00, 0x7f, 0x00, 0x00, 0x01 }}};
 
     /* Source-specific routes are not implemented yet for BSD. */
-    if(src_plen > 0) {
+    if(!is_default(src, src_plen)) {
         errno = ENOSYS;
         return -1;
     }

route.c

@@ -59,7 +59,7 @@ check_specific_first(void)
     int specific = 1;
     int i;
     for(i = 0; i < route_slots; i++) {
-        if(routes[i]->src->src_plen == 0) {
+        if(is_default(routes[i]->src->src_prefix, routes[i]->src->src_plen)) {
             specific = 0;
         } else if(!specific) {
             return 0;
@@ -78,11 +78,13 @@ route_compare(const unsigned char *prefix, unsigned char plen,
               struct babel_route *route)
 {
     int i;
+    int is_ss = !is_default(src_prefix, src_plen);
+    int is_ss_rt = !is_default(route->src->src_prefix, route->src->src_plen);
 
     /* Put all source-specific routes in the front of the list. */
-    if(src_plen == 0 && route->src->src_plen > 0) {
+    if(!is_ss && is_ss_rt) {
         return 1;
-    } else if(src_plen > 0 && route->src->src_plen == 0) {
+    } else if(is_ss && !is_ss_rt) {
         return -1;
     }
 
@@ -95,10 +97,7 @@ route_compare(const unsigned char *prefix, unsigned char plen,
     if(plen > route->src->plen)
         return 1;
 
-    if(src_plen == 0) {
-        if(route->src->src_plen > 0)
-            return -1;
-    } else {
+    if(is_ss) {
         i = memcmp(src_prefix, route->src->src_prefix, 16);
         if(i != 0)
             return i;
@@ -401,7 +400,8 @@ route_stream_next(struct route_stream *stream)
     if(stream->installed) {
         while(stream->index < route_slots)
             if(stream->installed == ROUTE_SS_INSTALLED &&
-               routes[stream->index]->src->src_plen == 0)
+               is_default(routes[stream->index]->src->src_prefix,
+                          routes[stream->index]->src->src_plen))
                 return NULL;
             else if(routes[stream->index]->installed)
                 break;
@@ -858,10 +858,9 @@ update_route(const unsigned char *id,
     }
 
     is_v4 = v4mapped(prefix);
-    if(src_plen != 0 && is_v4 != v4mapped(src_prefix))
+    if(is_v4 != v4mapped(src_prefix))
         return NULL;
 
-
     add_metric = input_filter(id, prefix, plen, src_prefix, src_plen,
                               neigh->address, neigh->ifp->ifindex);
     if(add_metric >= INFINITY)

rule.c

@@ -185,7 +185,7 @@ find_table(const unsigned char *dest, unsigned short plen,
     install_filter(dest, plen, src, src_plen, &filter_result);
     if(filter_result.table) {
         return filter_result.table;
-    } else if(src_plen == 0) {
+    } else if(is_default(src, src_plen)) {
         return export_table;
     } else if(kernel_disambiguate(v4mapped(dest))) {
         return export_table;

util.h

@@ -103,6 +103,12 @@ void v4tov6(unsigned char *dst, const unsigned char *src);
 int daemonise(void);
 int set_src_prefix(unsigned char *src_addr, unsigned char *src_plen);
 
+static inline int
+is_default(const unsigned char *prefix, int plen)
+{
+    return plen == 0 || (plen == 96 && v4mapped(prefix));
+}
+
 enum prefix_status {
     PST_EQUALS = 0,
     PST_DISJOINT,