From 4709b4faa43907ed9fcaf5920e56b6664f0523cf Mon Sep 17 00:00:00 2001
From: Daniel Walton <dwalton@cumulusnetworks.com>
Date: Mon, 31 Jul 2017 19:49:24 +0000
Subject: [PATCH] bgpd: peer hash expands until we are out of memory

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>
Reviewed-by:   CCR-6531

Ticket: CM-17352
---
 bgpd/bgpd.c | 5 +++--
 bgpd/bgpd.h | 1 +
 lib/hash.c  | 4 ++++
 lib/hash.h  | 3 +++
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index 0a4600a6f914..0fde22c76ac0 100644
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -747,7 +747,7 @@ static unsigned int peer_hash_key_make(void *p)
 	return sockunion_hash(&peer->su);
 }
 
-static int peer_hash_cmp(const void *p1, const void *p2)
+static int peer_hash_same(const void *p1, const void *p2)
 {
 	const struct peer *peer1 = p1;
 	const struct peer *peer2 = p2;
@@ -2758,7 +2758,8 @@ static struct bgp *bgp_create(as_t *as, const char *name,
 		XSTRDUP(MTYPE_BGP_PEER_HOST, "Static announcement");
 	bgp->peer = list_new();
 	bgp->peer->cmp = (int (*)(void *, void *))peer_cmp;
-	bgp->peerhash = hash_create(peer_hash_key_make, peer_hash_cmp, NULL);
+	bgp->peerhash = hash_create(peer_hash_key_make, peer_hash_same, NULL);
+	bgp->peerhash->max_size = BGP_PEER_MAX_HASH_SIZE;
 
 	bgp->group = list_new();
 	bgp->group->cmp = (int (*)(void *, void *))peer_group_cmp;
diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 9b2884438bbb..effe67f8f1f0 100644
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -36,6 +36,7 @@
 #include "bitfield.h"
 
 #define BGP_MAX_HOSTNAME 64	/* Linux max, is larger than most other sys */
+#define BGP_PEER_MAX_HASH_SIZE 16384
 
 /* Default interval for IPv6 RAs when triggered by BGP unnumbered neighbor. */
 #define BGP_UNNUM_DEFAULT_RA_INTERVAL 10
diff --git a/lib/hash.c b/lib/hash.c
index a7714f156930..e74e4355dc99 100644
--- a/lib/hash.c
+++ b/lib/hash.c
@@ -94,6 +94,10 @@ static void hash_expand(struct hash *hash)
 	struct hash_backet *hb, *hbnext, **new_index;
 
 	new_size = hash->size * 2;
+
+	if (hash->max_size && new_size > hash->max_size)
+		return;
+
 	new_index = XCALLOC(MTYPE_HASH_INDEX,
 			    sizeof(struct hash_backet *) * new_size);
 	if (new_index == NULL)
diff --git a/lib/hash.h b/lib/hash.h
index 6ce29f0426dc..236abbbd6a2c 100644
--- a/lib/hash.h
+++ b/lib/hash.h
@@ -64,6 +64,9 @@ struct hash {
 	/* Hash table size. Must be power of 2 */
 	unsigned int size;
 
+	/* If max_size is 0 there is no limit */
+	unsigned int max_size;
+
 	/* Key make function. */
 	unsigned int (*hash_key)(void *);