route: Fix OS route comparison

This at least works on a multi-homed NetBSD.

diff --git a/src/route.c b/src/route.c
index cf5268658ba1cd3ed7c51de4c8497de173dd78da..bcf477270866fd69cbf1118fc0a56afdd4fa1736 100644 (file)
--- a/src/route.c
+++ b/src/route.c
@@ -68,6 +68,32 @@ static size_t froutes;
 static size_t mroutes;
 #endif
 
+static void
+rt_maskedaddr(struct sockaddr *dst,
+       const struct sockaddr *addr, const struct sockaddr *netmask)
+{
+       const char *addrp = addr->sa_data, *netmaskp = netmask->sa_data;
+       char *dstp = dst->sa_data;
+       const char *addre = (char *)dst + sa_len(addr);
+       const char *netmaske = (char *)dst + MIN(sa_len(addr), sa_len(netmask));
+
+       dst->sa_family = addr->sa_family;
+#ifdef HAVE_SA_LEN
+       dst->sa_len = addr->sa_len;
+#endif
+
+       if (sa_is_unspecified(netmask)) {
+               if (addre > dstp)
+                       memcpy(dstp, addrp, (size_t)(addre - dstp));
+               return;
+       }
+
+       while (dstp < netmaske)
+               *dstp++ = *addrp++ & *netmaskp++;
+       if (dstp < addre)
+               memset(dstp, 0, (size_t)(addre - dstp));
+}
+
 /*
  * On some systems, host routes have no need for a netmask.
  * However DHCP specifies host routes using an all-ones netmask.
@@ -90,6 +116,8 @@ rt_compare(void *context, const void *node1, const void *node2)
 {
        const struct rt *rt1 = node1, *rt2 = node2;
        bool rt1u, rt2u;
+       union sa_ss ma1 = { .sa.sa_family = AF_UNSPEC };
+       union sa_ss ma2 = { .sa.sa_family = AF_UNSPEC };
        int c;
        struct interface *ifp1, *ifp2;
 
@@ -103,14 +131,20 @@ rt_compare(void *context, const void *node1, const void *node2)
        if (rt1u != rt2u)
                return rt1u ? 1 : -1;
 
-       /* Sort by destination and netmask. */
-       c = sa_cmp(&rt1->rt_dest, &rt2->rt_dest);
-       if (c != 0)
-               return c;
-       c = rt_cmp_netmask(rt1, rt2);
+       /* Sort by masked destination. */
+       rt_maskedaddr(&ma1.sa, &rt1->rt_dest, &rt1->rt_netmask);
+       rt_maskedaddr(&ma2.sa, &rt2->rt_dest, &rt2->rt_netmask);
+       c = sa_cmp(&ma1.sa, &ma2.sa);
        if (c != 0)
                return c;
 
+#ifndef HAVE_ROUTE_METRIC
+       if (context == &rt_compare_os)
+               return 0;
+#else
+       UNUSED(context);
+#endif
+
        /* All other checks are by interface. */
        if (rt1->rt_ifp == NULL || rt2->rt_ifp == NULL)
                return 0;
@@ -122,12 +156,6 @@ rt_compare(void *context, const void *node1, const void *node2)
        if (c != 0)
                return -c;
 
-#ifndef HAVE_ROUTE_METRIC
-       if (context == &rt_compare_os)
-               return 0;
-#else
-       UNUSED(context);
-#endif
        /* Lower metric interfaces come first */
        return (int)(ifp1->metric - ifp2->metric);
 }