Static: Support for multiple routes with the same network

Add support for proper handling of multiple routes with the same network
to the static protocol. Routes are distinguished by internal index, which
is assigned automatically (sequentially for routes within each network).
Having different route preference or igp_metric attribute is optional.

2 files changed, 82 insertions, 16 deletions

diff --git a/proto/static/static.c b/proto/static/static.c
index 16a981ed..7b22d49b 100644
--- a/proto/static/static.c
+++ b/proto/static/static.c
@@ -49,11 +49,14 @@
 
 static linpool *static_lp;
 
+static inline struct rte_src * static_get_source(struct static_proto *p, uint i)
+{ return i ? rt_get_source(&p->p, i) : p->p.main_source; }
+
 static void
 static_announce_rte(struct static_proto *p, struct static_route *r)
 {
   rta *a = allocz(RTA_MAX_SIZE);
-  a->src = p->p.main_source;
+  a->src = static_get_source(p, r->index);
   a->source = RTS_STATIC;
   a->scope = SCOPE_UNIVERSE;
   a->dest = r->dest;
@@ -105,7 +108,7 @@ static_announce_rte(struct static_proto *p, struct static_route *r)
   if (r->cmds)
     f_eval_rte(r->cmds, &e, static_lp);
 
-  rte_update(&p->p, r->net, e);
+  rte_update2(p->p.main_channel, r->net, e, a->src);
   r->state = SRS_CLEAN;
 
   if (r->cmds)
@@ -117,7 +120,7 @@ withdraw:
   if (r->state == SRS_DOWN)
     return;
 
-  rte_update(&p->p, r->net, NULL);
+  rte_update2(p->p.main_channel, r->net, NULL, a->src);
   r->state = SRS_DOWN;
 }
 
@@ -250,7 +253,7 @@ static void
 static_remove_rte(struct static_proto *p, struct static_route *r)
 {
   if (r->state)
-    rte_update(&p->p, r->net, NULL);
+    rte_update2(p->p.main_channel, r->net, NULL, static_get_source(p, r->index));
 
   static_reset_rte(p, r);
 }
@@ -354,11 +357,22 @@ static_bfd_notify(struct bfd_request *req)
 }
 
 static int
-static_rte_mergable(rte *pri UNUSED, rte *sec UNUSED)
+static_rte_better(rte *new, rte *old)
 {
-  return 1;
+  u32 n = ea_get_int(new->attrs->eattrs, EA_GEN_IGP_METRIC, IGP_METRIC_UNKNOWN);
+  u32 o = ea_get_int(old->attrs->eattrs, EA_GEN_IGP_METRIC, IGP_METRIC_UNKNOWN);
+  return n < o;
+}
+
+static int
+static_rte_mergable(rte *pri, rte *sec)
+{
+  u32 a = ea_get_int(pri->attrs->eattrs, EA_GEN_IGP_METRIC, IGP_METRIC_UNKNOWN);
+  u32 b = ea_get_int(sec->attrs->eattrs, EA_GEN_IGP_METRIC, IGP_METRIC_UNKNOWN);
+  return a == b;
 }
 
+static void static_index_routes(struct static_config *cf);
 
 static void
 static_postconfig(struct proto_config *CF)
@@ -382,6 +396,8 @@ static_postconfig(struct proto_config *CF)
   WALK_LIST(r, cf->routes)
     if (r->net && (r->net->type != CF->net_type))
       cf_error("Route %N incompatible with channel type", r->net);
+
+  static_index_routes(cf);
 }
 
 static struct proto *
@@ -394,6 +410,7 @@ static_init(struct proto_config *CF)
   P->main_channel = proto_add_channel(P, proto_cf_main_channel(CF));
 
   P->neigh_notify = static_neigh_notify;
+  P->rte_better = static_rte_better;
   P->rte_mergable = static_rte_mergable;
 
   if (cf->igp_table_ip4)
@@ -463,7 +480,7 @@ static_cleanup(struct proto *P)
 static void
 static_dump_rte(struct static_route *r)
 {
-  debug("%-1N: ", r->net);
+  debug("%-1N (%u): ", r->net, r->index);
   if (r->dest == RTD_UNICAST)
     if (r->iface && ipa_zero(r->via))
       debug("dev %s\n", r->iface->name);
@@ -486,11 +503,48 @@ static_dump(struct proto *P)
 
 #define IGP_TABLE(cf, sym) ((cf)->igp_table_##sym ? (cf)->igp_table_##sym ->table : NULL )
 
-static inline int
-static_cmp_rte(const void *X, const void *Y)
+static inline int srt_equal(const struct static_route *a, const struct static_route *b)
+{ return net_equal(a->net, b->net) && (a->index == b->index); }
+
+static inline int srt_compare(const struct static_route *a, const struct static_route *b)
+{ return net_compare(a->net, b->net) ?: uint_cmp(a->index, b->index); }
+
+static inline int srt_compare_qsort(const void *A, const void *B)
 {
-  struct static_route *x = *(void **)X, *y = *(void **)Y;
-  return net_compare(x->net, y->net);
+  return srt_compare(*(const struct static_route * const *)A,
+		     *(const struct static_route * const *)B);
+}
+
+static void
+static_index_routes(struct static_config *cf)
+{
+  struct static_route *rt, **buf;
+  uint num, i, v;
+
+  num = list_length(&cf->routes);
+  buf = xmalloc(num * sizeof(void *));
+
+  /* Initialize with sequential indexes to ensure stable sorting */
+  i = 0;
+  WALK_LIST(rt, cf->routes)
+  {
+    buf[i] = rt;
+    rt->index = i++;
+  }
+
+  qsort(buf, num, sizeof(struct static_route *), srt_compare_qsort);
+
+  /* Compute proper indexes - sequential for routes with same network */
+  for (i = 0, v = 0, rt = NULL; i < num; i++, v++)
+  {
+    if (rt && !net_equal(buf[i]->net, rt->net))
+      v = 0;
+
+    rt = buf[i];
+    rt->index = v;
+  }
+
+  xfree(buf);
 }
 
 static int
@@ -519,7 +573,7 @@ static_reconfigure(struct proto *P, struct proto_config *CF)
 
   /* Reconfigure initial matching sequence */
   for (or = HEAD(o->routes), nr = HEAD(n->routes);
-       NODE_VALID(or) && NODE_VALID(nr) && net_equal(or->net, nr->net);
+       NODE_VALID(or) && NODE_VALID(nr) && srt_equal(or, nr);
        or = NODE_NEXT(or), nr = NODE_NEXT(nr))
     static_reconfigure_rte(p, or, nr);
 
@@ -545,12 +599,12 @@ static_reconfigure(struct proto *P, struct proto_config *CF)
   for (i = 0, nr2 = nr; i < nrnum; i++, nr2 = NODE_NEXT(nr2))
     nrbuf[i] = nr2;
 
-  qsort(orbuf, ornum, sizeof(struct static_route *), static_cmp_rte);
-  qsort(nrbuf, nrnum, sizeof(struct static_route *), static_cmp_rte);
+  qsort(orbuf, ornum, sizeof(struct static_route *), srt_compare_qsort);
+  qsort(nrbuf, nrnum, sizeof(struct static_route *), srt_compare_qsort);
 
   while ((orpos < ornum) && (nrpos < nrnum))
   {
-    int x = net_compare(orbuf[orpos]->net, nrbuf[nrpos]->net);
+    int x = srt_compare(orbuf[orpos], nrbuf[nrpos]);
     if (x < 0)
       static_remove_rte(p, orbuf[orpos++]);
     else if (x > 0)
@@ -603,6 +657,16 @@ static_copy_config(struct proto_config *dest, struct proto_config *src)
 }
 
 static void
+static_get_route_info(rte *rte, byte *buf)
+{
+  eattr *a = ea_find(rte->attrs->eattrs, EA_GEN_IGP_METRIC);
+  if (a)
+    buf += bsprintf(buf, " (%d/%u)", rte->pref, a->u.data);
+  else
+    buf += bsprintf(buf, " (%d)", rte->pref);
+}
+
+static void
 static_show_rt(struct static_route *r)
 {
   switch (r->dest)
@@ -665,5 +729,6 @@ struct protocol proto_static = {
   .shutdown =		static_shutdown,
   .cleanup =		static_cleanup,
   .reconfigure =	static_reconfigure,
-  .copy_config =	static_copy_config
+  .copy_config =	static_copy_config,
+  .get_route_info =	static_get_route_info,
 };
diff --git a/proto/static/static.h b/proto/static/static.h
index f736996c..af714b72 100644
--- a/proto/static/static.h
+++ b/proto/static/static.h
@@ -40,6 +40,7 @@ struct static_route {
   struct static_route *mp_head;		/* First nexthop of this route */
   struct static_route *mp_next;		/* Nexthops for multipath routes */
   struct f_line *cmds;			/* List of commands for setting attributes */
+  uint index;				/* Distinguish different routes with same net */
   byte dest;				/* Destination type (RTD_*) */
   byte state;				/* State of route announcement (SRS_*) */
   byte active;				/* Next hop is active (nbr/iface/BFD available) */