[dpdk-dev] [PATCH 07/10] ip_frag: fix order of arguments to key compare function

[Anatoly Burakov <anatoly.burakov@intel.com>]

when using key compare function, it uses key length of the first
argument to determine how long should be the keys that are compared.
however, currently we are passing a key from the fragmentation table as
first argument. the problem with this is that this key is potentially
uninitialized (i.e. contains all zeroes, including key length). this
leads to a nasty bug of comparing only the key id's and not keys
themselves.

of course, a safer way would be to do RTE_MAX between key lengths, but
since this compare is done per-packet, every cycle counts, so we just
use the key whos length is guaranteed to be correct because it comes
from an actual packet.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---
 lib/librte_ip_frag/ip_frag_internal.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/librte_ip_frag/ip_frag_internal.c b/lib/librte_ip_frag/ip_frag_internal.c
index 6203740..a2c645b 100644
--- a/lib/librte_ip_frag/ip_frag_internal.c
+++ b/lib/librte_ip_frag/ip_frag_internal.c
@@ -346,7 +346,7 @@ ip_frag_lookup(struct rte_ip_frag_tbl *tbl,
 	max_cycles = tbl->max_cycles;
 	assoc = tbl->bucket_entries;
 
-	if (tbl->last != NULL && ip_frag_key_cmp(&tbl->last->key, key) == 0)
+	if (tbl->last != NULL && ip_frag_key_cmp(key, &tbl->last->key) == 0)
 		return (tbl->last);
 
 	/* different hashing methods for IPv4 and IPv6 */
@@ -378,7 +378,7 @@ ip_frag_lookup(struct rte_ip_frag_tbl *tbl,
 					p1, i, assoc,
 			IPv6_KEY_BYTES(p1[i].key.src_dst), p1[i].key.id, p1[i].start);
 
-		if (ip_frag_key_cmp(&p1[i].key, key) == 0)
+		if (ip_frag_key_cmp(key, &p1[i].key) == 0)
 			return (p1 + i);
 		else if (ip_frag_key_is_empty(&p1[i].key))
 			empty = (empty == NULL) ? (p1 + i) : empty;
@@ -404,7 +404,7 @@ ip_frag_lookup(struct rte_ip_frag_tbl *tbl,
 					p2, i, assoc,
 			IPv6_KEY_BYTES(p2[i].key.src_dst), p2[i].key.id, p2[i].start);
 
-		if (ip_frag_key_cmp(&p2[i].key, key) == 0)
+		if (ip_frag_key_cmp(key, &p2[i].key) == 0)
 			return (p2 + i);
 		else if (ip_frag_key_is_empty(&p2[i].key))
 			empty = (empty == NULL) ?( p2 + i) : empty;
-- 
1.8.1.4