When a new conntrack zone is entered, the ct_state field is zeroed in order to avoid using state information from different zones.
One such scenario is when a packet is double NATed. Assuming two zones and 3 flows performing the following actions in order on the packet: 1. ct(zone=5,nat), recirc 2. ct(zone=1), recirc 3. ct(zone=1,nat) If at step #1 the packet matches an existing NAT entry, it will get translated and pkt->md.ct_state is set to CS_DST_NAT or CS_SRC_NAT. At step #2 the new tuple might match an existing connection and pkt->md.ct_zone is set to 1. If at step #3 the packet matches an existing NAT entry in zone 1, handle_nat() will be called to perform the translation but it will return early because the packet's zone matches the conntrack zone and the ct_state field still contains CS_DST_NAT or CS_SRC_NAT from the translations in zone 5. In order to reliably detect when a packet enters a new conntrack zone we also need to zero out the pkt->md.ct_zone field when initializing metadata in pkt_metadata_init(). CC: Darrell Ball <[email protected]> Signed-off-by: Dumitru Ceara <[email protected]> --- lib/conntrack.c | 5 +++++ lib/packets.h | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/lib/conntrack.c b/lib/conntrack.c index ff5a894..e4d934a 100644 --- a/lib/conntrack.c +++ b/lib/conntrack.c @@ -1277,6 +1277,11 @@ process_one(struct conntrack *ct, struct dp_packet *pkt, const struct nat_action_info_t *nat_action_info, ovs_be16 tp_src, ovs_be16 tp_dst, const char *helper) { + /* Reset ct_state whenever entering a new zone. */ + if (pkt->md.ct_zone != zone) { + pkt->md.ct_state = 0; + } + bool create_new_conn = false; conn_key_lookup(ct, &ctx->key, ctx->hash, now, &ctx->conn, &ctx->reply); struct conn *conn = ctx->conn; diff --git a/lib/packets.h b/lib/packets.h index 5d7f82c..fae64bb 100644 --- a/lib/packets.h +++ b/lib/packets.h @@ -161,6 +161,11 @@ pkt_metadata_init(struct pkt_metadata *md, odp_port_t port) */ memset(md, 0, offsetof(struct pkt_metadata, ct_orig_tuple_ipv6)); + /* Explicitly zero out ct_zone in order to be able to properly determine + * when a packet enters a new conntrack zone. + */ + md->ct_zone = 0; + /* It can be expensive to zero out all of the tunnel metadata. However, * we can just zero out ip_dst and the rest of the data will never be * looked at. */ -- 1.8.3.1 _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
