[ovs-dev] [PATCH ovn v2] Allow explicit setting of the SNAT zone on a gateway router.
Numan Siddique
numans at ovn.org
Mon Nov 16 09:19:47 UTC 2020
On Thu, Nov 12, 2020 at 8:26 PM Mark Michelson <mmichels at redhat.com> wrote:
>
> In certain situations, OVN may coexist with other applications on a
> host. Traffic from OVN and the other applications may then go out a
> shared gateway. If OVN traffic and the other application traffic use
> different conntrack zones for SNAT, then it is possible for the shared
> gateway to assign conflicting source IP:port combinations. By sharing
> the same conntrack zone, there will be no conflicting assignments.
>
> In this commit, we introduce options:snat-ct-zone for northbound logical
> routers. By setting this option, users can explicitly set the conntrack
> zone for the logical router so that it will match the zone used by
> non-OVN traffic on the host.
>
> The biggest side effects of this patch are:
> 1) southbound datapath changes now result in recalculating CT zones in
> ovn-controller. This can result in recomputing physical flows in more
> situations than previously.
> 2) The table 65 flow to transition between datapaths is no longer
> associated with a port binding. This is because the flow refers to
> the peer datapath's CT zones, which can now be updated due to changes
> on that datapath. The flow therefore may need to be updated either
> due to the port binding being changed or the peer datapath being
> changed.
>
> Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1892311
> Signed-off-by: Mark Michelson <mmichels at redhat.com>
Hi Mark,
Thanks for the patch.
I did some testing with the below logical resources
******
switch 0ff55345-e283-4ed7-8c7f-8475a8a8f968 (sw1)
port sw1-lr0
type: router
addresses: ["00:00:00:00:ff:02"]
router-port: lr0-sw1
port sw1-port2
addresses: ["40:54:00:00:00:04 20.0.0.4"]
switch bddcdd29-9b32-482a-b9a6-0f9fa1a0e25a (sw0)
port sw0-lr0
type: router
addresses: ["00:00:00:00:ff:01"]
router-port: lr0-sw0
port sw0-port1
addresses: ["50:54:00:00:00:03 10.0.0.3"]
port sw0-lr1
type: router
router-port: lr1-sw0
router 9462469c-d799-4d28-bccd-80e9a8c68e24 (lr1)
port lr1-sw0
mac: "00:00:00:00:fa:21"
networks: ["10.0.0.20/24"]
router 96b14269-65ad-4ae9-9fa6-e4ef2a344a54 (lr0)
port lr0-sw1
mac: "00:00:00:00:ff:02"
networks: ["20.0.0.1/24"]
port lr0-public
mac: "00:00:20:20:12:13"
networks: ["172.168.0.100/24"]
gateway chassis: [chassis-1]
*****
If I set - "ovn-nbctl set logical_router lr0 options:snat-ct-zone=x"
and If 'x' is already allocated for sw0 snat, then the
both sw0 snat and lr0 snat share the same zone id. Is that expected ?
If I set the same zone id 'y' for both lr0 and lr1, then I observed
that both lr0 and lr1 have the same zone id 'y' and I also
see the warning in the ovn-controller log.
Later if I change the zone of lr1 to 'z' and then lr0 to 'z', the lr0
is not updated with 'z'. So lr0 will have 'y' and lr1 will have 'z'.
Seems like it's not consistent.
Can there be a possibility that there are 2 shared gateways in one
node and both want to share the same zone id ?
i.e lr0 is associated with one shared gateway and lr1 with another
shared gateway (on the same host) and both want to use the zone id 0 ?
Thanks
Numan
> ---
> controller/ovn-controller.c | 89 +++++++++++++++++++++++++++++++-----
> controller/physical.c | 2 +-
> lib/ovn-util.c | 7 +++
> lib/ovn-util.h | 1 +
> northd/ovn-northd.c | 10 ++++
> ovn-nb.xml | 7 +++
> tests/ovn.at | 91 +++++++++++++++++++++++++++++++++++++
> 7 files changed, 194 insertions(+), 13 deletions(-)
>
> diff --git a/controller/ovn-controller.c b/controller/ovn-controller.c
> index a06cae3cc..54c8fd2db 100644
> --- a/controller/ovn-controller.c
> +++ b/controller/ovn-controller.c
> @@ -531,6 +531,21 @@ update_sb_db(struct ovsdb_idl *ovs_idl, struct ovsdb_idl *ovnsb_idl,
> }
> }
>
> +static void
> +add_pending_ct_zone_entry(struct shash *pending_ct_zones,
> + enum ct_zone_pending_state state,
> + int zone, bool add, const char *name)
> +{
> + VLOG_DBG("%s ct zone %"PRId32" for '%s'",
> + add ? "assigning" : "removing", zone, name);
> +
> + struct ct_zone_pending_entry *pending = xmalloc(sizeof *pending);
> + pending->state = state; /* Skip flushing zone. */
> + pending->zone = zone;
> + pending->add = add;
> + shash_add(pending_ct_zones, name, pending);
> +}
> +
> static void
> update_ct_zones(const struct sset *lports, const struct hmap *local_datapaths,
> struct simap *ct_zones, unsigned long *ct_zone_bitmap,
> @@ -540,6 +555,7 @@ update_ct_zones(const struct sset *lports, const struct hmap *local_datapaths,
> int scan_start = 1;
> const char *user;
> struct sset all_users = SSET_INITIALIZER(&all_users);
> + struct simap req_snat_zones = SIMAP_INITIALIZER(&req_snat_zones);
>
> SSET_FOR_EACH(user, lports) {
> sset_add(&all_users, user);
> @@ -554,6 +570,25 @@ update_ct_zones(const struct sset *lports, const struct hmap *local_datapaths,
> char *snat = alloc_nat_zone_key(&ld->datapath->header_.uuid, "snat");
> sset_add(&all_users, dnat);
> sset_add(&all_users, snat);
> +
> + int req_snat_zone = datapath_snat_ct_zone(ld->datapath);
> + if (req_snat_zone >= 0) {
> + struct simap_node *node;
> + bool collision = false;
> + SIMAP_FOR_EACH (node, &req_snat_zones) {
> + if (node->data == req_snat_zone) {
> + VLOG_WARN("Datapaths %.*s and " UUID_FMT " request SNAT "
> + "CT zone %d\n", UUID_LEN, node->name,
> + UUID_ARGS(&ld->datapath->header_.uuid),
> + req_snat_zone);
> + collision = true;
> + break;
> + }
> + }
> + if (!collision) {
> + simap_put(&req_snat_zones, snat, req_snat_zone);
> + }
> + }
> free(dnat);
> free(snat);
> }
> @@ -564,17 +599,51 @@ update_ct_zones(const struct sset *lports, const struct hmap *local_datapaths,
> VLOG_DBG("removing ct zone %"PRId32" for '%s'",
> ct_zone->data, ct_zone->name);
>
> - struct ct_zone_pending_entry *pending = xmalloc(sizeof *pending);
> - pending->state = CT_ZONE_DB_QUEUED; /* Skip flushing zone. */
> - pending->zone = ct_zone->data;
> - pending->add = false;
> - shash_add(pending_ct_zones, ct_zone->name, pending);
> + add_pending_ct_zone_entry(pending_ct_zones, CT_ZONE_DB_QUEUED,
> + ct_zone->data, false, ct_zone->name);
>
> bitmap_set0(ct_zone_bitmap, ct_zone->data);
> simap_delete(ct_zones, ct_zone);
> }
> }
>
> + /* Prioritize requested CT zones */
> + struct simap_node *snat_req_node;
> + SIMAP_FOR_EACH (snat_req_node, &req_snat_zones) {
> + struct simap_node *node = simap_find(ct_zones, snat_req_node->name);
> + if (node) {
> + if (node->data == snat_req_node->data) {
> + /* Already have this zone reserved */
> + continue;
> + } else {
> + /* Zone has changed for this node. delete old entry */
> + bitmap_set0(ct_zone_bitmap, node->data);
> + simap_delete(ct_zones, node);
> + }
> + } else if (snat_req_node->data > 0 &&
> + bitmap_is_set(ct_zone_bitmap, snat_req_node->data)) {
> + /* Uh oh. Someone else already has this zone assigned.
> + * We need to find who and remove them from ct_zones so
> + * that they get re-assigned a new zone below
> + */
> + struct simap_node *next;
> + SIMAP_FOR_EACH_SAFE (node, next, ct_zones) {
> + if (node->data == snat_req_node->data) {
> + simap_delete(ct_zones, node);
> + break;
> + }
> + }
> + }
> +
> + add_pending_ct_zone_entry(pending_ct_zones, CT_ZONE_OF_QUEUED,
> + snat_req_node->data, true,
> + snat_req_node->name);
> +
> + bitmap_set1(ct_zone_bitmap, snat_req_node->data);
> + simap_put(ct_zones, snat_req_node->name, snat_req_node->data);
> + }
> + simap_destroy(&req_snat_zones);
> +
> /* xxx This is wasteful to assign a zone to each port--even if no
> * xxx security policy is applied. */
>
> @@ -596,13 +665,8 @@ update_ct_zones(const struct sset *lports, const struct hmap *local_datapaths,
> }
> scan_start = zone + 1;
>
> - VLOG_DBG("assigning ct zone %"PRId32" to '%s'", zone, user);
> -
> - struct ct_zone_pending_entry *pending = xmalloc(sizeof *pending);
> - pending->state = CT_ZONE_OF_QUEUED;
> - pending->zone = zone;
> - pending->add = true;
> - shash_add(pending_ct_zones, user, pending);
> + add_pending_ct_zone_entry(pending_ct_zones, CT_ZONE_OF_QUEUED,
> + zone, true, user);
>
> bitmap_set1(ct_zone_bitmap, zone);
> simap_put(ct_zones, user, zone);
> @@ -2330,6 +2394,7 @@ main(int argc, char *argv[])
>
> engine_add_input(&en_ct_zones, &en_ovs_open_vswitch, NULL);
> engine_add_input(&en_ct_zones, &en_ovs_bridge, NULL);
> + engine_add_input(&en_ct_zones, &en_sb_datapath_binding, NULL);
> engine_add_input(&en_ct_zones, &en_runtime_data, NULL);
>
> engine_add_input(&en_runtime_data, &en_ofctrl_is_connected, NULL);
> diff --git a/controller/physical.c b/controller/physical.c
> index 1bc2c389b..00c4ca4fd 100644
> --- a/controller/physical.c
> +++ b/controller/physical.c
> @@ -926,7 +926,7 @@ consider_port_binding(struct ovsdb_idl_index *sbrec_port_binding_by_name,
>
> ofctrl_add_flow(flow_table, OFTABLE_LOG_TO_PHY, 100,
> binding->header_.uuid.parts[0],
> - &match, ofpacts_p, &binding->header_.uuid);
> + &match, ofpacts_p, hc_uuid);
> return;
> }
>
> diff --git a/lib/ovn-util.c b/lib/ovn-util.c
> index 18aac8da3..f0fb796b4 100644
> --- a/lib/ovn-util.c
> +++ b/lib/ovn-util.c
> @@ -532,6 +532,13 @@ datapath_is_switch(const struct sbrec_datapath_binding *ldp)
> {
> return smap_get(&ldp->external_ids, "logical-switch") != NULL;
> }
> +
> +int
> +datapath_snat_ct_zone(const struct sbrec_datapath_binding *dp)
> +{
> + return smap_get_int(&dp->external_ids, "snat-ct-zone", -1);
> +}
> +
>
> struct tnlid_node {
> struct hmap_node hmap_node;
> diff --git a/lib/ovn-util.h b/lib/ovn-util.h
> index 3496673b2..ea8226571 100644
> --- a/lib/ovn-util.h
> +++ b/lib/ovn-util.h
> @@ -107,6 +107,7 @@ uint32_t ovn_logical_flow_hash(const struct uuid *logical_datapath,
> uint16_t priority,
> const char *match, const char *actions);
> bool datapath_is_switch(const struct sbrec_datapath_binding *);
> +int datapath_snat_ct_zone(const struct sbrec_datapath_binding *ldp);
> void ovn_conn_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
> const char *argv[] OVS_UNUSED, void *idl_);
>
> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> index 4d4190cb9..8ce756c8a 100644
> --- a/northd/ovn-northd.c
> +++ b/northd/ovn-northd.c
> @@ -1179,6 +1179,16 @@ ovn_datapath_update_external_ids(struct ovn_datapath *od)
> smap_add(&ids, "interconn-ts", ts);
> }
> }
> +
> + /* Set snat-ct-zone */
> + if (od->nbr) {
> + int nat_default_ct = smap_get_int(&od->nbr->options,
> + "snat-ct-zone", -1);
> + if (nat_default_ct >= 0) {
> + smap_add_format(&ids, "snat-ct-zone", "%d", nat_default_ct);
> + }
> + }
> +
> sbrec_datapath_binding_set_external_ids(od->sb, &ids);
> smap_destroy(&ids);
> }
> diff --git a/ovn-nb.xml b/ovn-nb.xml
> index 5e6c6c7a3..619c0e299 100644
> --- a/ovn-nb.xml
> +++ b/ovn-nb.xml
> @@ -1961,6 +1961,13 @@
> unique key for each datapath by itself. However, if it is configured,
> <code>ovn-northd</code> honors the configured value.
> </column>
> + <column name="options" key="snat-ct-zone"
> + type='{"type": "integer", "minInteger": 0, "maxInteger": 65535}'>
> + Use the requested conntrack zone for SNAT with this router. This can be
> + useful if egress traffic from the host running OVN comes from both OVN
> + and other sources. This way, OVN and the other sources can make use of
> + the same conntrack zone.
> + </column>
> </group>
>
> <group title="Common Columns">
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 378d11921..4f8c1a3e1 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -22686,3 +22686,94 @@ AT_CHECK([test "$encap_rec_mvtep" == "$encap_rec_mvtep1"], [0], [])
>
> OVN_CLEANUP([hv1])
> AT_CLEANUP
> +
> +AT_SETUP([ovn -- snat default ct zone])
> +ovn_start
> +
> +net_add n1
> +sim_add hv1
> +ovs-vsctl add-br br-phys
> +as hv1
> +ovn_attach n1 br-phys 192.168.0.10
> +
> +ovn-nbctl ls-add sw0
> +ovn-nbctl lsp-add sw0 sw0-p1
> +ovn-nbctl lsp-set-addresses sw0-p1 "00:00:00:00:00:02 10.0.0.2"
> +
> +ovn-nbctl lr-add gw_router
> +ovn-nbctl set Logical_Router gw_router options:chassis="hv1"
> +
> +ovn-nbctl lrp-add gw_router gw_router-sw0 00:00:00:00:00:01 10.0.0.1/24
> +ovn-nbctl lsp-add sw0 sw0-gw_router
> +ovn-nbctl lsp-set-addresses sw0-gw_router router
> +ovn-nbctl set Logical_Switch_Port sw0-gw_router type=router \
> + options:router-port=gw_router-sw0 \
> +
> +ovn-nbctl lr-nat-add gw_router snat 192.168.0.1 10.0.0.0/24
> +
> +as hv1 ovs-vsctl -- add-port br-int hv1-vif1 -- \
> + set interface hv1-vif1 external-ids:iface-id=sw0-p1
> +
> +ovn-nbctl --wait=hv sync
> +
> +ro_nb_uuid=$(ovn-nbctl get Logical_Router gw_router _uuid)
> +sw_nb_uuid=$(ovn-nbctl get Logical_Switch sw0 _uuid)
> +ro_sb_uuid=$(ovn-sbctl --bare --columns=_uuid find Datapath_Binding external-ids:logical-router=${ro_nb_uuid})
> +sw_sb_uuid=$(ovn-sbctl --bare --columns=_uuid find Datapath_Binding external-ids:logical-switch=${sw_nb_uuid})
> +ro_meta=$(ovn-sbctl get Datapath_Binding ${ro_sb_uuid} tunnel_key)
> +ro_meta=$(printf %#x ${ro_meta})
> +sw_meta=$(ovn-sbctl get Datapath_Binding ${sw_sb_uuid} tunnel_key)
> +sw_meta=$(printf %#x ${sw_meta})
> +
> +echo "ro_nb_uuid: ${ro_nb_uuid}"
> +echo "sw_nb_uuid: ${sw_nb_uuid}"
> +echo "ro_sb_uuid: ${ro_sb_uuid}"
> +echo "sw_sb_uuid: ${sw_sb_uuid}"
> +echo "ro_meta: ${ro_meta}"
> +echo "sw_meta: ${sw_meta}"
> +
> +as hv1
> +ovs-vsctl list bridge br-int
> +snat_zone=$(printf %#x $(ovs-vsctl get bridge br-int external-ids:ct-zone-${ro_sb_uuid}_snat | tr -d \"))
> +
> +echo "snat_zone: ${snat_zone}"
> +
> +as hv1 ovs-ofctl dump-flows br-int > offlows_pre
> +AT_CAPTURE_FILE([offlows_pre])
> +# We should have a flow in table 33 that transitions from the ingress pipeline
> +# to the egress pipeline of gw_router.
> +AT_CHECK_UNQUOTED([grep -c "table=33.*metadata=${ro_meta}.*load:${snat_zone}->NXM_NX_REG12[]" offlows_pre], [0], [dnl
> +1
> +])
> +
> +# We should have a flow in table 65 that transitions from the egress pipeline
> +# of sw0 to the ingress pipeline of gw_router.
> +AT_CHECK_UNQUOTED([grep -c "table=65.*metadata=${sw_meta}.*load:${snat_zone}->NXM_NX_REG12[]" offlows_pre], [0], [dnl
> +1
> +])
> +
> +ovn-nbctl --wait=hv set Logical_Router gw_router options:snat-ct-zone=666
> +
> +as hv1
> +snat_zone=$(ovs-vsctl get bridge br-int external-ids:ct-zone-${ro_sb_uuid}_snat | tr -d \")
> +
> +echo "snat_zone: ${snat_zone}"
> +
> +AT_CHECK([test "${snat_zone}" = "666"], [0], [])
> +
> +as hv1 ovs-ofctl dump-flows br-int > offlows_post
> +AT_CAPTURE_FILE([offlows_post])
> +# We should have a flow in table 33 that transitions from the ingress pipeline
> +# to the egress pipeline of gw_router.
> +AT_CHECK_UNQUOTED([grep -c "table=33.*metadata=${ro_meta}.*load:0x29a->NXM_NX_REG12[]" offlows_post], [0], [dnl
> +1
> +])
> +
> +# We should have a flow in table 65 that transitions from the egress pipeline
> +# of sw0 to the ingress pipeline of gw_router.
> +AT_CHECK_UNQUOTED([grep -c "table=65.*metadata=${sw_meta}.*load:0x29a->NXM_NX_REG12[]" offlows_post], [0], [dnl
> +1
> +])
> +
> +OVN_CLEANUP([hv1])
> +AT_CLEANUP
> --
> 2.25.4
>
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