Encapsulate testing for ipv6_subtrees within a function.

disambiguation.c

@@ -266,7 +266,7 @@ kinstall_route(const struct babel_route *route)
            format_prefix(route->src->prefix, route->src->plen),
            format_prefix(route->src->src_prefix, route->src->src_plen));
     /* Install source-specific conflicting routes */
-    if(!has_ipv6_subtrees || v4) {
+    if(!kernel_disambiguate(v4)) {
         stream = route_stream(1);
         if(!stream) {
             fprintf(stderr, "Couldn't allocate route stream.\n");
@@ -330,7 +330,7 @@ kuninstall_route(const struct babel_route *route)
         perror("kernel_route(FLUSH)");
 
     /* Remove source-specific conflicting routes */
-    if(!has_ipv6_subtrees || v4) {
+    if(!kernel_disambiguate(v4)) {
         stream = route_stream(1);
         if(!stream) {
             fprintf(stderr, "Couldn't allocate route stream.\n");
@@ -376,7 +376,7 @@ kswitch_routes(const struct babel_route *old, const struct babel_route *new)
     }
 
     /* Remove source-specific conflicting routes */
-    if(!has_ipv6_subtrees || v4mapped(old->nexthop)) {
+    if(!kernel_disambiguate(v4mapped(old->nexthop))) {
         stream = route_stream(1);
         if(!stream) {
             fprintf(stderr, "Couldn't allocate route stream.\n");
@@ -423,7 +423,7 @@ kchange_route_metric(const struct babel_route *route,
         return -1;
     }
 
-    if(!has_ipv6_subtrees || v4mapped(route->nexthop)) {
+    if(!kernel_disambiguate(v4mapped(route->nexthop))) {
         stream = route_stream(1);
         if(!stream) {
             fprintf(stderr, "Couldn't allocate route stream.\n");

kernel.h

@@ -65,6 +65,7 @@ int kernel_interface_ipv4(const char *ifname, int ifindex,
 int kernel_interface_mtu(const char *ifname, int ifindex);
 int kernel_interface_wireless(const char *ifname, int ifindex);
 int kernel_interface_channel(const char *ifname, int ifindex);
+int kernel_disambiguate(int v4);
 int kernel_route(int operation, const unsigned char *dest, unsigned short plen,
                  const unsigned char *src, unsigned short src_plen,
                  const unsigned char *gate, int ifindex, unsigned int metric,

kernel_netlink.c

@@ -917,6 +917,14 @@ kernel_interface_channel(const char *ifname, int ifindex)
         return -1;
 }
 
+/* Return true if we cannot handle disambiguation ourselves. */
+
+int
+kernel_disambiguate(int v4)
+{
+    return !v4 && has_ipv6_subtrees;
+}
+
 int
 kernel_route(int operation, const unsigned char *dest, unsigned short plen,
              const unsigned char *src, unsigned short src_plen,
@@ -994,7 +1002,7 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
 
     if(src_plen == 0) {
         table = export_table;
-    } else if(has_ipv6_subtrees && !ipv4) {
+    } else if(kernel_disambiguate(ipv4)) {
         table = export_table;
         use_src = 1;
     } else {
@@ -1841,7 +1849,7 @@ find_table(const unsigned char *src, unsigned short src_plen)
     int i, new_i;
 
     if(src_plen == 0 ||
-       (has_ipv6_subtrees && (src_plen < 96 || !v4mapped(src)))) {
+       (kernel_disambiguate(src_plen >= 96  && v4mapped(src)))) {
         fprintf(stderr, "Find_table called for route handled by kernel "
                 "(this shouldn't happen).");
         return -1;

kernel_socket.c

@@ -382,6 +382,12 @@ kernel_interface_channel(const char *ifname, int ifindex)
     return -1;
 }
 
+int
+kernel_disambiguate(int v4)
+{
+    return 0;
+}
+
 int
 kernel_route(int operation, const unsigned char *dest, unsigned short plen,
              const unsigned char *src, unsigned short src_plen,