bgpd: optimize bgp_nexthop_self()

  This function scores 2nd, profiling a full internet table load. It's called
for every prefix received.
  Instead of looping in the interface lists comparing addresses use a hash
to mantain them.

* bgpd.c: Init the own address hash.
* bgp_nexthop.c: Introduce methods to maintain an own address hash.
  (bgp_connected_add) add addresses to the hash.
  (bgp_connected_delete) delete addresses from the hash.
  (bgp_nexthop_self) lookup addresses in the hash. Removed the unused afi_t
  parameter.
* bgp_route.c: (bgp_update_main) Micro-optimization, rearranged condition to
  not lookup the hash for bogus nexthops (0.0.0.0 or a class D/E address)

Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

1 files changed, 90 insertions, 16 deletions

diff --git a/bgpd/bgp_nexthop.c b/bgpd/bgp_nexthop.c
index fdf251b2..723057b6 100644
--- a/bgpd/bgp_nexthop.c
+++ b/bgpd/bgp_nexthop.c
@@ -28,6 +28,8 @@ Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 #include "network.h"
 #include "log.h"
 #include "memory.h"
+#include "hash.h"
+#include "jhash.h"
 
 #include "bgpd/bgpd.h"
 #include "bgpd/bgp_table.h"
@@ -524,6 +526,83 @@ bgp_scan_timer (struct thread *t)
 
   return 0;
 }
+
+/* BGP own address structure */
+struct bgp_addr
+{
+  struct in_addr addr;
+  int refcnt;
+};
+
+static struct hash *bgp_address_hash;
+
+static void *
+bgp_address_hash_alloc (void *p)
+{
+  struct in_addr *val = p;
+  struct bgp_addr *addr;
+
+  addr = XMALLOC (MTYPE_BGP_ADDR, sizeof (struct bgp_addr));
+  addr->refcnt = 0;
+  addr->addr.s_addr = val->s_addr;
+
+  return addr;
+}
+
+static unsigned int
+bgp_address_hash_key_make (void *p)
+{
+  const struct bgp_addr *addr = p;
+
+  return jhash_1word(addr->addr.s_addr, 0);
+}
+
+static int
+bgp_address_hash_cmp (const void *p1, const void *p2)
+{
+  const struct bgp_addr *addr1 = p1;
+  const struct bgp_addr *addr2 = p2;
+
+  return addr1->addr.s_addr == addr2->addr.s_addr;
+}
+
+void
+bgp_address_init (void)
+{
+  bgp_address_hash = hash_create (bgp_address_hash_key_make,
+                                  bgp_address_hash_cmp);
+}
+
+static void
+bgp_address_add (struct prefix *p)
+{
+  struct bgp_addr tmp;
+  struct bgp_addr *addr;
+
+  tmp.addr = p->u.prefix4;
+
+  addr = hash_get (bgp_address_hash, &tmp, bgp_address_hash_alloc);
+  addr->refcnt++;
+}
+
+static void
+bgp_address_del (struct prefix *p)
+{
+  struct bgp_addr tmp;
+  struct bgp_addr *addr;
+
+  tmp.addr = p->u.prefix4;
+
+  addr = hash_lookup (bgp_address_hash, &tmp);
+  addr->refcnt--;
+
+  if (addr->refcnt == 0)
+    {
+      hash_release (bgp_address_hash, addr);
+      XFREE (MTYPE_BGP_ADDR, addr);
+    }
+}
+
 
 struct bgp_connected_ref
 {
@@ -557,6 +636,8 @@ bgp_connected_add (struct connected *ifc)
       if (prefix_ipv4_any ((struct prefix_ipv4 *) &p))
 	return;
 
+      bgp_address_add (addr);
+
       rn = bgp_node_get (bgp_connected_table[AFI_IP], (struct prefix *) &p);
       if (rn->info)
 	{
@@ -622,6 +703,8 @@ bgp_connected_delete (struct connected *ifc)
       if (prefix_ipv4_any ((struct prefix_ipv4 *) &p))
 	return;
 
+      bgp_address_del (addr);
+
       rn = bgp_node_lookup (bgp_connected_table[AFI_IP], &p);
       if (! rn)
 	return;
@@ -666,25 +749,16 @@ bgp_connected_delete (struct connected *ifc)
 }
 
 int
-bgp_nexthop_self (afi_t afi, struct attr *attr)
+bgp_nexthop_self (struct attr *attr)
 {
-  struct listnode *node;
-  struct listnode *node2;
-  struct interface *ifp;
-  struct connected *ifc;
-  struct prefix *p;
+  struct bgp_addr tmp, *addr;
 
-  for (ALL_LIST_ELEMENTS_RO (iflist, node, ifp))
-    {
-      for (ALL_LIST_ELEMENTS_RO (ifp->connected, node2, ifc))
-	{
-	  p = ifc->address;
+  tmp.addr = attr->nexthop;
+
+  addr = hash_lookup (bgp_address_hash, &tmp);
+  if (addr)
+    return 1;
 
-	  if (p && p->family == AF_INET 
-	      && IPV4_ADDR_SAME (&p->u.prefix4, &attr->nexthop))
-	    return 1;
-	}
-    }
   return 0;
 }