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authorKlement Sekera <ksekera@cisco.com>2021-12-17 12:47:51 +0000
committerOle Tr�an <otroan@employees.org>2021-12-20 10:05:20 +0000
commit4ab6ad136b62add35598f3c354231701b7c14c65 (patch)
tree5cff25e84550e4b7855774e7213efd61bfe7a5cc
parente3241f04410fa45099f958f77636b80293904fc3 (diff)
ip: SVR fix race condition
There could be a race condition where two fragments of one chain end up at the same time on different workers, one overwriting others hash entry. Add a check for that and restart processing on the unlucky worker who ends up being second from hash table POV. This will then result in a proper handover to worker now owning this reassembly. Type: fix Fixes: de34c35fc73226943538149fae9dbc5cfbdc6e75 Signed-off-by: Klement Sekera <ksekera@cisco.com> Change-Id: I9eb29c5cb1ffe3b5eb1d5a638e17ab7ba2628d28
-rw-r--r--src/vnet/ip/reass/ip4_sv_reass.c8
-rw-r--r--src/vnet/ip/reass/ip6_sv_reass.c8
2 files changed, 14 insertions, 2 deletions
diff --git a/src/vnet/ip/reass/ip4_sv_reass.c b/src/vnet/ip/reass/ip4_sv_reass.c
index f5fa575e64d..9971dafd9fd 100644
--- a/src/vnet/ip/reass/ip4_sv_reass.c
+++ b/src/vnet/ip/reass/ip4_sv_reass.c
@@ -321,6 +321,8 @@ ip4_sv_reass_find_or_create (vlib_main_t * vm, ip4_sv_reass_main_t * rm,
ip4_sv_reass_t *reass = NULL;
f64 now = vlib_time_now (vm);
+again:
+
if (!clib_bihash_search_16_8 (&rm->hash, &kv->kv, &kv->kv))
{
if (vm->thread_index != kv->v.thread_index)
@@ -375,10 +377,14 @@ ip4_sv_reass_find_or_create (vlib_main_t * vm, ip4_sv_reass_main_t * rm,
kv->v.thread_index = vm->thread_index;
reass->last_heard = now;
- if (clib_bihash_add_del_16_8 (&rm->hash, &kv->kv, 1))
+ int rv = clib_bihash_add_del_16_8 (&rm->hash, &kv->kv, 2);
+ if (rv)
{
ip4_sv_reass_free (vm, rm, rt, reass);
reass = NULL;
+ // if other worker created a context already work with the other copy
+ if (-2 == rv)
+ goto again;
}
return reass;
diff --git a/src/vnet/ip/reass/ip6_sv_reass.c b/src/vnet/ip/reass/ip6_sv_reass.c
index 58c7d8d8433..23ae6784127 100644
--- a/src/vnet/ip/reass/ip6_sv_reass.c
+++ b/src/vnet/ip/reass/ip6_sv_reass.c
@@ -311,6 +311,8 @@ ip6_sv_reass_find_or_create (vlib_main_t *vm, ip6_sv_reass_main_t *rm,
ip6_sv_reass_t *reass = NULL;
f64 now = vlib_time_now (vm);
+again:
+
if (!clib_bihash_search_48_8 (&rm->hash, &kv->kv, &kv->kv))
{
if (vm->thread_index != kv->v.thread_index)
@@ -370,10 +372,14 @@ ip6_sv_reass_find_or_create (vlib_main_t *vm, ip6_sv_reass_main_t *rm,
kv->v.thread_index = vm->thread_index;
reass->last_heard = now;
- if (clib_bihash_add_del_48_8 (&rm->hash, &kv->kv, 1))
+ int rv = clib_bihash_add_del_48_8 (&rm->hash, &kv->kv, 2);
+ if (rv)
{
ip6_sv_reass_free (vm, rm, rt, reass);
reass = NULL;
+ // if other worker created a context already work with the other copy
+ if (-2 == rv)
+ goto again;
}
return reass;