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authorNathan Skrzypczak <nathan.skrzypczak@gmail.com>2022-02-02 19:31:43 +0100
committerBeno�t Ganne <bganne@cisco.com>2022-03-18 11:33:51 +0000
commit762cfd408b16b6ab43ade3ab491292b93bdeb9b3 (patch)
tree3b303cb9db68a8003aca57820174b03902f3c714 /src/plugins/cnat/cnat_session.c
parent6798e9ec34a49df008ecb7f84559e531f6c0d651 (diff)
cnat: Fix conflicting rsession
When dNAT-ing to a VIP, it can happen that the return session conflicts with another forward session than the one we own. This patchs adds a rsession_flags CNAT_SESSION_RETRY_SNAT that makes cnat_session_create search for a free src port to use for the resulting return session. It also makes forward & return session share their fate in the session scanner. Type: fix Change-Id: Id0edf59abf8e5bc0c0d8941ba289c4563c77dee0 Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>
Diffstat (limited to 'src/plugins/cnat/cnat_session.c')
-rw-r--r--src/plugins/cnat/cnat_session.c35
1 files changed, 33 insertions, 2 deletions
diff --git a/src/plugins/cnat/cnat_session.c b/src/plugins/cnat/cnat_session.c
index 216d2575c37..fa04de602b4 100644
--- a/src/plugins/cnat/cnat_session.c
+++ b/src/plugins/cnat/cnat_session.c
@@ -172,15 +172,43 @@ cnat_session_purge (void)
return (0);
}
+void
+cnat_reverse_session_free (cnat_session_t *session)
+{
+ cnat_bihash_kv_t bkey, bvalue;
+ cnat_session_t *rsession = (cnat_session_t *) &bkey;
+ int rv;
+
+ ip46_address_copy (&rsession->key.cs_ip[VLIB_RX],
+ &session->value.cs_ip[VLIB_TX]);
+ ip46_address_copy (&rsession->key.cs_ip[VLIB_TX],
+ &session->value.cs_ip[VLIB_RX]);
+ rsession->key.cs_proto = session->key.cs_proto;
+ rsession->key.cs_loc = session->key.cs_loc == CNAT_LOCATION_OUTPUT ?
+ CNAT_LOCATION_INPUT :
+ CNAT_LOCATION_OUTPUT;
+ rsession->key.__cs_pad = 0;
+ rsession->key.cs_af = session->key.cs_af;
+ rsession->key.cs_port[VLIB_RX] = session->value.cs_port[VLIB_TX];
+ rsession->key.cs_port[VLIB_TX] = session->value.cs_port[VLIB_RX];
+
+ rv = cnat_bihash_search_i2 (&cnat_session_db, &bkey, &bvalue);
+ if (!rv)
+ {
+ /* other session is in bihash */
+ cnat_session_t *rsession = (cnat_session_t *) &bvalue;
+ cnat_session_free (rsession);
+ }
+}
+
u64
cnat_session_scan (vlib_main_t * vm, f64 start_time, int i)
{
BVT (clib_bihash) * h = &cnat_session_db;
int j, k;
- /* Don't scan the l2 fib if it hasn't been instantiated yet */
if (alloc_arena (h) == 0)
- return 0.0;
+ return 0;
for ( /* caller saves starting point */ ; i < h->nbuckets; i++)
{
@@ -219,6 +247,9 @@ cnat_session_scan (vlib_main_t * vm, f64 start_time, int i)
cnat_timestamp_exp (session->value.cs_ts_index))
{
/* age it */
+ cnat_reverse_session_free (session);
+ /* this should be last as deleting the session memset it to
+ * 0xff */
cnat_session_free (session);
/*