Kernel-side implementation of source-sensitive routing.

kernel.h

@@ -28,6 +28,8 @@ THE SOFTWARE.
 struct kernel_route {
     unsigned char prefix[16];
     int plen;
+    unsigned char src_prefix[16];
+    int src_plen; /* no source prefix <=> src_plen == 0 */
     int metric;
     unsigned int ifindex;
     int proto;
@@ -60,6 +62,7 @@ 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_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,
                  const unsigned char *newgate, int newifindex,
                  unsigned int newmetric);

kernel_netlink.c

@@ -554,6 +554,7 @@ kernel_setup(int setup)
 
         return 1;
     } else {
+        release_tables();
         close(dgram_socket);
         dgram_socket = -1;
 
@@ -912,16 +913,16 @@ kernel_interface_channel(const char *ifname, int ifindex)
 
 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,
              const unsigned char *newgate, int newifindex,
              unsigned int newmetric)
 {
-
     union { char raw[1024]; struct nlmsghdr nh; } buf;
     struct rtmsg *rtm;
     struct rtattr *rta;
     int len = sizeof(buf.raw);
-    int rc, ipv4;
+    int rc, ipv4, table;
 
     if(!nl_setup) {
         fprintf(stderr,"kernel_route: netlink not initialized.\n");
@@ -941,14 +942,19 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
         }
     }
 
+    table = find_table(src, src_plen);
+    if(table < 0)
+        return -1;
+
     /* Check that the protocol family is consistent. */
     if(plen >= 96 && v4mapped(dest)) {
-        if(!v4mapped(gate)) {
+        if(!v4mapped(gate) ||
+           (src_plen > 0 && (!v4mapped(src) || src_plen < 96))) {
             errno = EINVAL;
             return -1;
         }
     } else {
-        if(v4mapped(gate)) {
+        if(v4mapped(gate)|| (src_plen > 0 && v4mapped(src))) {
             errno = EINVAL;
             return -1;
         }
@@ -967,9 +973,11 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
            stick with the naive approach, and hope that the window is
            small enough to be negligible. */
         kernel_route(ROUTE_FLUSH, dest, plen,
+                     src, src_plen,
                      gate, ifindex, metric,
                      NULL, 0, 0);
         rc = kernel_route(ROUTE_ADD, dest, plen,
+                          src, src_plen,
                           newgate, newifindex, newmetric,
                           NULL, 0, 0);
         if(rc < 0) {
@@ -981,11 +989,12 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
         return rc;
     }
 
-    kdebugf("kernel_route: %s %s/%d metric %d dev %d nexthop %s\n",
-           operation == ROUTE_ADD ? "add" :
-           operation == ROUTE_FLUSH ? "flush" : "???",
-           format_address(dest), plen, metric, ifindex,
-           format_address(gate));
+    kdebugf("kernel_route: %s %s from %s "
+            "table %d metric %d dev %d nexthop %s\n",
+            operation == ROUTE_ADD ? "add" :
+            operation == ROUTE_FLUSH ? "flush" : "???",
+            format_prefix(dest, plen), format_prefix(src, src_plen),
+            table, metric, ifindex, format_address(gate));
 
     /* Unreachable default routes cause all sort of weird interactions;
        ignore them. */
@@ -1004,7 +1013,7 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
     rtm = NLMSG_DATA(&buf.nh);
     rtm->rtm_family = ipv4 ? AF_INET : AF_INET6;
     rtm->rtm_dst_len = ipv4 ? plen - 96 : plen;
-    rtm->rtm_table = export_table;
+    rtm->rtm_table = table;
     rtm->rtm_scope = RT_SCOPE_UNIVERSE;
     if(metric < KERNEL_INFINITY)
         rtm->rtm_type = RTN_UNICAST;

kernel_socket.c

@@ -29,8 +29,6 @@ THE SOFTWARE.
 #include <unistd.h>
 #include <fcntl.h>
 #include <time.h>
-
-
 #include <strings.h>
 #include <netinet/in.h>
 #include <netinet/icmp6.h>
@@ -53,7 +51,6 @@ THE SOFTWARE.
 
 static int get_sdl(struct sockaddr_dl *sdl, char *ifname);
 
-
 static const unsigned char v4prefix[16] =
     {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
 
@@ -387,6 +384,7 @@ kernel_interface_channel(const char *ifname, int ifindex)
 
 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,
              const unsigned char *newgate, int newifindex,
              unsigned int newmetric)
@@ -427,9 +425,11 @@ kernel_route(int operation, const unsigned char *dest, unsigned short plen,
 
         /* Avoid atomic route changes that is buggy on OS X. */
         kernel_route(ROUTE_FLUSH, dest, plen,
+                     src, src_plen,
                      gate, ifindex, metric,
                      NULL, 0, 0);
         return kernel_route(ROUTE_ADD, dest, plen,
+                            src, src_plen,
                             newgate, newifindex, newmetric,
                             NULL, 0, 0);
 
@@ -668,7 +668,7 @@ kernel_routes(struct kernel_route *routes, int maxroutes)
     size_t len;
     struct rt_msghdr *rtm;
     int rc, i;
-    
+
     mib[0] = CTL_NET;
     mib[1] = PF_ROUTE;
     mib[2] = 0;

route.c

@@ -416,6 +416,7 @@ install_route(struct babel_route *route)
     }
 
     rc = kernel_route(ROUTE_ADD, route->src->prefix, route->src->plen,
+                      zeroes, 0,
                       route->nexthop,
                       route->neigh->ifp->ifindex,
                       metric_to_kernel(route_metric(route)), NULL, 0, 0);
@@ -440,6 +441,7 @@ uninstall_route(struct babel_route *route)
         return;
 
     rc = kernel_route(ROUTE_FLUSH, route->src->prefix, route->src->plen,
+                      zeroes, 0,
                       route->nexthop,
                       route->neigh->ifp->ifindex,
                       metric_to_kernel(route_metric(route)), NULL, 0, 0);
@@ -472,6 +474,7 @@ switch_routes(struct babel_route *old, struct babel_route *new)
                 "(this shouldn't happen).");
 
     rc = kernel_route(ROUTE_MODIFY, old->src->prefix, old->src->plen,
+                      zeroes, 0,
                       old->nexthop, old->neigh->ifp->ifindex,
                       metric_to_kernel(route_metric(old)),
                       new->nexthop, new->neigh->ifp->ifindex,
@@ -502,6 +505,7 @@ change_route_metric(struct babel_route *route,
     if(route->installed && old != new) {
         int rc;
         rc = kernel_route(ROUTE_MODIFY, route->src->prefix, route->src->plen,
+                          zeroes, 0,
                           route->nexthop, route->neigh->ifp->ifindex,
                           old,
                           route->nexthop, route->neigh->ifp->ifindex,

xroute.c

@@ -170,7 +170,7 @@ check_xroutes(int send_updates)
     debugf("\nChecking kernel routes.\n");
 
  again:
-    routes = malloc(maxroutes * sizeof(struct kernel_route));
+    routes = calloc(maxroutes, sizeof(struct kernel_route));
     if(routes == NULL)
         return -1;