[ovs-dev] [PATCH v3 ovn] northd: add reject action for lb with no backends

Numan Siddique numans at ovn.org
Fri Dec 11 09:37:07 UTC 2020


On Thu, Dec 10, 2020 at 3:18 AM Mark Michelson <mmichels at redhat.com> wrote:
>
> Acked-by: Mark Michelson <mmichels at redhat.com>

Thanks Lorenzo for v2 and Mark. I applied this patch to master.

Numan

>
> On 12/9/20 6:25 AM, Lorenzo Bianconi wrote:
> > Introduce the capability to create a load balancer with no backends and
> > with --reject option in order to send a TCP reset segment (for tcp) or
> > an ICMP port unreachable packet (for all other kind of traffic) whenever
> > an incoming packet is received for this load-balancer.
> >
> > Tested-by: Antonio Ojea <aojeagar at redhat.com>
> > Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
> > ---
> > Changes since v2:
> > - introduce ovn-northd.at self-test
> >
> > Changes since v1:
> > - add reject action for health_check empty lb
> > - rename build_lb_vip_ct_lb_actions in build_lb_vip_actions
> > - improve documentation
> > ---
> >   lib/lb.c                  |  2 ++
> >   lib/lb.h                  |  1 +
> >   northd/ovn-northd.8.xml   | 19 +++++++++++++++++
> >   northd/ovn-northd.c       | 44 ++++++++++++++++++++++++++-------------
> >   ovn-nb.ovsschema          |  9 ++++++--
> >   ovn-nb.xml                | 10 +++++++++
> >   tests/ovn-northd.at       | 25 ++++++++++++++++++++++
> >   tests/system-ovn.at       | 28 ++++++++++++++++++++++++-
> >   utilities/ovn-nbctl.8.xml | 11 +++++++++-
> >   utilities/ovn-nbctl.c     |  7 ++++++-
> >   10 files changed, 136 insertions(+), 20 deletions(-)
> >
> > diff --git a/lib/lb.c b/lib/lb.c
> > index a90042e58..2517c02ef 100644
> > --- a/lib/lb.c
> > +++ b/lib/lb.c
> > @@ -189,6 +189,8 @@ ovn_northd_lb_create(const struct nbrec_load_balancer *nbrec_lb,
> >           struct ovn_lb_vip *lb_vip = &lb->vips[n_vips];
> >           struct ovn_northd_lb_vip *lb_vip_nb = &lb->vips_nb[n_vips];
> >
> > +        lb_vip->empty_backend_rej = smap_get_bool(&nbrec_lb->options,
> > +                                                  "reject", false);
> >           if (!ovn_lb_vip_init(lb_vip, node->key, node->value)) {
> >               continue;
> >           }
> > diff --git a/lib/lb.h b/lib/lb.h
> > index 6644ad0d8..42c580bd1 100644
> > --- a/lib/lb.h
> > +++ b/lib/lb.h
> > @@ -49,6 +49,7 @@ struct ovn_lb_vip {
> >
> >       struct ovn_lb_backend *backends;
> >       size_t n_backends;
> > +    bool empty_backend_rej;
> >   };
> >
> >   struct ovn_lb_backend {
> > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > index 294402de3..8bbe577b6 100644
> > --- a/northd/ovn-northd.8.xml
> > +++ b/northd/ovn-northd.8.xml
> > @@ -700,6 +700,16 @@
> >           ct_lb(<var>args</var>)</code>, where <var>args</var> contains comma
> >           separated IP addresses of the same address family as <var>VIP</var>.
> >         </li>
> > +
> > +      <li>
> > +        If the load balancer is created with <code>--reject</code> option and
> > +        it has no active backends, a TCP reset segment (for tcp) or an ICMP
> > +        port unreachable packet (for all other kind of traffic) will be sent
> > +        whenever an incoming packet is received for this load-balancer.
> > +        Please note using <code>--reject</code> option will disable
> > +        empty_lb SB controller event for this load balancer.
> > +      </li>
> > +
> >         <li>
> >           A priority-100 flow commits packets to connection tracker using
> >           <code>ct_commit; next;</code> action based on a hint provided by
> > @@ -2592,6 +2602,15 @@ icmp6 {
> >           packets, the above action will be replaced by
> >           <code>flags.force_snat_for_lb = 1; ct_dnat;</code>.
> >         </li>
> > +
> > +      <li>
> > +        If the load balancer is created with <code>--reject</code> option and
> > +        it has no active backends, a TCP reset segment (for tcp) or an ICMP
> > +        port unreachable packet (for all other kind of traffic) will be sent
> > +        whenever an incoming packet is received for this load-balancer.
> > +        Please note using <code>--reject</code> option will disable
> > +        empty_lb SB controller event for this load balancer.
> > +      </li>
> >       </ul>
> >
> >       <p>Ingress Table 6: DNAT on Gateway Routers</p>
> > diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> > index 957242367..6b83f8e9e 100644
> > --- a/northd/ovn-northd.c
> > +++ b/northd/ovn-northd.c
> > @@ -3436,12 +3436,12 @@ ovn_lb_svc_create(struct northd_context *ctx, struct ovn_northd_lb *lb,
> >   }
> >
> >   static
> > -void build_lb_vip_ct_lb_actions(struct ovn_lb_vip *lb_vip,
> > -                                struct ovn_northd_lb_vip *lb_vip_nb,
> > -                                struct ds *action,
> > -                                char *selection_fields)
> > +void build_lb_vip_actions(struct ovn_lb_vip *lb_vip,
> > +                          struct ovn_northd_lb_vip *lb_vip_nb,
> > +                          struct ds *action, char *selection_fields,
> > +                          bool ls_dp)
> >   {
> > -    bool skip_hash_fields = false;
> > +    bool skip_hash_fields = false, reject = false;
> >
> >       if (lb_vip_nb->lb_health_check) {
> >           ds_put_cstr(action, "ct_lb(backends=");
> > @@ -3463,18 +3463,30 @@ void build_lb_vip_ct_lb_actions(struct ovn_lb_vip *lb_vip,
> >           }
> >
> >           if (!n_active_backends) {
> > -            skip_hash_fields = true;
> > -            ds_clear(action);
> > -            ds_put_cstr(action, "drop;");
> > +            if (!lb_vip->empty_backend_rej) {
> > +                ds_clear(action);
> > +                ds_put_cstr(action, "drop;");
> > +                skip_hash_fields = true;
> > +            } else {
> > +                reject = true;
> > +            }
> >           } else {
> >               ds_chomp(action, ',');
> >               ds_put_cstr(action, ");");
> >           }
> > +    } else if (lb_vip->empty_backend_rej && !lb_vip->n_backends) {
> > +        reject = true;
> >       } else {
> >           ds_put_format(action, "ct_lb(backends=%s);", lb_vip_nb->backend_ips);
> >       }
> >
> > -    if (!skip_hash_fields && selection_fields && selection_fields[0]) {
> > +    if (reject) {
> > +        int stage = ls_dp ? ovn_stage_get_table(S_SWITCH_OUT_QOS_MARK)
> > +                          : ovn_stage_get_table(S_ROUTER_OUT_SNAT);
> > +        ds_clear(action);
> > +        ds_put_format(action, "reg0 = 0; reject { outport <-> inport; "
> > +                      "next(pipeline=egress,table=%d);};", stage);
> > +    } else if (!skip_hash_fields && selection_fields && selection_fields[0]) {
> >           ds_chomp(action, ';');
> >           ds_chomp(action, ')');
> >           ds_put_format(action, "; hash_fields=\"%s\");", selection_fields);
> > @@ -5078,7 +5090,8 @@ build_empty_lb_event_flow(struct ovn_datapath *od, struct hmap *lflows,
> >                             struct nbrec_load_balancer *lb,
> >                             int pl, struct shash *meter_groups)
> >   {
> > -    if (!controller_event_en || lb_vip->n_backends) {
> > +    if (!controller_event_en || lb_vip->n_backends ||
> > +        lb_vip->empty_backend_rej) {
> >           return;
> >       }
> >
> > @@ -5968,8 +5981,8 @@ build_lb_rules(struct ovn_datapath *od, struct hmap *lflows,
> >
> >           /* New connections in Ingress table. */
> >           struct ds action = DS_EMPTY_INITIALIZER;
> > -        build_lb_vip_ct_lb_actions(lb_vip, lb_vip_nb, &action,
> > -                                   lb->selection_fields);
> > +        build_lb_vip_actions(lb_vip, lb_vip_nb, &action,
> > +                             lb->selection_fields, true);
> >
> >           struct ds match = DS_EMPTY_INITIALIZER;
> >           ds_put_format(&match, "ct.new && %s.dst == %s", ip_match,
> > @@ -9679,8 +9692,8 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> >                   struct ovn_lb_vip *lb_vip = &lb->vips[j];
> >                   struct ovn_northd_lb_vip *lb_vip_nb = &lb->vips_nb[j];
> >                   ds_clear(&actions);
> > -                build_lb_vip_ct_lb_actions(lb_vip, lb_vip_nb, &actions,
> > -                                           lb->selection_fields);
> > +                build_lb_vip_actions(lb_vip, lb_vip_nb, &actions,
> > +                                     lb->selection_fields, false);
> >
> >                   if (!sset_contains(&all_ips, lb_vip->vip_str)) {
> >                       sset_add(&all_ips, lb_vip->vip_str);
> > @@ -9731,7 +9744,8 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> >                       prio = 120;
> >                   }
> >
> > -                if (od->l3redirect_port) {
> > +                if (od->l3redirect_port &&
> > +                    (lb_vip->n_backends || !lb_vip->empty_backend_rej)) {
> >                       ds_put_format(&match, " && is_chassis_resident(%s)",
> >                                     od->l3redirect_port->json_key);
> >                   }
> > diff --git a/ovn-nb.ovsschema b/ovn-nb.ovsschema
> > index 269e3a888..af77dd138 100644
> > --- a/ovn-nb.ovsschema
> > +++ b/ovn-nb.ovsschema
> > @@ -1,7 +1,7 @@
> >   {
> >       "name": "OVN_Northbound",
> > -    "version": "5.28.0",
> > -    "cksum": "610359755 26847",
> > +    "version": "5.29.0",
> > +    "cksum": "328602112 27064",
> >       "tables": {
> >           "NB_Global": {
> >               "columns": {
> > @@ -188,6 +188,11 @@
> >                                   ["eth_src", "eth_dst", "ip_src", "ip_dst",
> >                                    "tp_src", "tp_dst"]]},
> >                                "min": 0, "max": "unlimited"}},
> > +                "options": {
> > +                     "type": {"key": "string",
> > +                              "value": "string",
> > +                              "min": 0,
> > +                              "max": "unlimited"}},
> >                   "external_ids": {
> >                       "type": {"key": "string", "value": "string",
> >                                "min": 0, "max": "unlimited"}}},
> > diff --git a/ovn-nb.xml b/ovn-nb.xml
> > index c9ab25ceb..e7a8d6833 100644
> > --- a/ovn-nb.xml
> > +++ b/ovn-nb.xml
> > @@ -1635,6 +1635,16 @@
> >           See <em>External IDs</em> at the beginning of this document.
> >         </column>
> >       </group>
> > +    <group title="Load_Balancer options">
> > +      <column name="options" key="reject" type='{"type": "boolean"}'>
> > +        If the load balancer is created with <code>--reject</code> option and
> > +        it has no active backends, a TCP reset segment (for tcp) or an ICMP
> > +        port unreachable packet (for all other kind of traffic) will be sent
> > +        whenever an incoming packet is received for this load-balancer.
> > +        Please note using <code>--reject</code> option will disable empty_lb
> > +        SB controller event for this load balancer.
> > +      </column>
> > +    </group>
> >     </table>
> >
> >     <table name="Load_Balancer_Health_Check" title="load balancer">
> > diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> > index 90ca0a4db..50a4cae76 100644
> > --- a/tests/ovn-northd.at
> > +++ b/tests/ovn-northd.at
> > @@ -1233,6 +1233,31 @@ wait_row_count Service_Monitor 2
> >   ovn-nbctl --wait=sb lb-del lb2
> >   wait_row_count Service_Monitor 0
> >
> > +check ovn-nbctl --reject lb-add lb3 10.0.0.10:80 10.0.0.3:80,20.0.0.3:80
> > +check ovn-nbctl --wait=sb set load_balancer lb3 ip_port_mappings:10.0.0.3=sw0-p1:10.0.0.2
> > +check ovn-nbctl --wait=sb set load_balancer lb3 ip_port_mappings:20.0.0.3=sw1-p1:20.0.0.2
> > +wait_row_count Service_Monitor 0
> > +
> > +check ovn-nbctl --wait=sb ls-lb-add sw0 lb3
> > +AT_CHECK([ovn-nbctl --wait=sb -- --id=@hc create \
> > +Load_Balancer_Health_Check vip="10.0.0.10\:80" -- add Load_Balancer lb3 \
> > +health_check @hc | uuidfilt], [0], [<0>
> > +])
> > +wait_row_count Service_Monitor 2
> > +
> > +# Set the service monitor for sw0-p1 and sw1-p1 to online
> > +sm_sw0_p1=$(fetch_column Service_Monitor _uuid logical_port=sw0-p1)
> > +sm_sw1_p1=$(fetch_column Service_Monitor _uuid logical_port=sw1-p1)
> > +
> > +ovn-sbctl set service_monitor $sm_sw0_p1 status=offline
> > +ovn-sbctl set service_monitor $sm_sw1_p1 status=offline
> > +
> > +AT_CAPTURE_FILE([sbflows12])
> > +OVS_WAIT_FOR_OUTPUT(
> > +  [ovn-sbctl dump-flows sw0 | tee sbflows12 | grep "ip4.dst == 10.0.0.10 && tcp.dst == 80" | grep priority=120 | sed 's/table=..//'], [0], [dnl
> > +  (ls_in_stateful     ), priority=120  , match=(ct.new && ip4.dst == 10.0.0.10 && tcp.dst == 80), action=(reg0 = 0; reject { outport <-> inport; next(pipeline=egress,table=6);};)
> > +])
> > +
> >   AT_CLEANUP
> >
> >   AT_SETUP([ovn -- Load balancer VIP in NAT entries])
> > diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> > index d59f7c97e..1e73001ab 100644
> > --- a/tests/system-ovn.at
> > +++ b/tests/system-ovn.at
> > @@ -1574,6 +1574,18 @@ OVS_WAIT_UNTIL([
> >       grep "selection_method=hash,fields(ip_src,ip_dst,sctp_src,sctp_dst)" -c) -eq 2
> >   ])
> >
> > +ovn-nbctl --reject lb-add lb3 30.0.0.10:80 ""
> > +ovn-nbctl ls-lb-add foo lb3
> > +# Filter reset segments
> > +NS_CHECK_EXEC([foo1], [tcpdump -c 1 -neei foo1 ip[[33:1]]=0x14 > rst.pcap &])
> > +sleep 1
> > +NS_CHECK_EXEC([foo1], [wget -q 30.0.0.10],[4])
> > +
> > +OVS_WAIT_UNTIL([
> > +    n_reset=$(cat rst.pcap | wc -l)
> > +    test "${n_reset}" = "1"
> > +])
> > +
> >   OVS_APP_EXIT_AND_WAIT([ovn-controller])
> >
> >   as ovn-sb
> > @@ -4151,7 +4163,7 @@ ovn-nbctl lsp-set-type sw1-lr0 router
> >   ovn-nbctl lsp-set-addresses sw1-lr0 router
> >   ovn-nbctl lsp-set-options sw1-lr0 router-port=lr0-sw1
> >
> > -ovn-nbctl lb-add lb1 10.0.0.10:80 10.0.0.3:80,20.0.0.3:80
> > +ovn-nbctl --reject lb-add lb1 10.0.0.10:80 10.0.0.3:80,20.0.0.3:80
> >
> >   ovn-nbctl --wait=sb set load_balancer . ip_port_mappings:10.0.0.3=sw0-p1:10.0.0.2
> >   ovn-nbctl --wait=sb set load_balancer . ip_port_mappings:20.0.0.3=sw1-p1:20.0.0.2
> > @@ -4266,6 +4278,20 @@ ovn-sbctl list service_monitor
> >   OVS_WAIT_UNTIL([test 2 = `ovn-sbctl --bare --columns status find \
> >   service_monitor protocol=udp | sed '/^$/d' | grep offline | wc -l`])
> >
> > +# Stop webserer in sw1-p1
> > +pid_file=$(cat l7_pid_file)
> > +NS_CHECK_EXEC([sw1-p1], [kill $(cat $pid_file)])
> > +
> > +NS_CHECK_EXEC([sw0-p2], [tcpdump -c 1 -neei sw0-p2 ip[[33:1]]=0x14 > rst.pcap &])
> > +OVS_WAIT_UNTIL([test 2 = `ovn-sbctl --bare --columns status find \
> > +service_monitor protocol=tcp | sed '/^$/d' | grep offline | wc -l`])
> > +NS_CHECK_EXEC([sw0-p2], [wget 10.0.0.10 -v -o wget$i.log],[4])
> > +
> > +OVS_WAIT_UNTIL([
> > +    n_reset=$(cat rst.pcap | wc -l)
> > +    test "${n_reset}" = "1"
> > +])
> > +
> >   OVS_APP_EXIT_AND_WAIT([ovn-controller])
> >
> >   as ovn-sb
> > diff --git a/utilities/ovn-nbctl.8.xml b/utilities/ovn-nbctl.8.xml
> > index 59302296b..e5a35f307 100644
> > --- a/utilities/ovn-nbctl.8.xml
> > +++ b/utilities/ovn-nbctl.8.xml
> > @@ -903,7 +903,7 @@
> >
> >       <h1>Load Balancer Commands</h1>
> >       <dl>
> > -      <dt>[<code>--may-exist</code> | <code>--add-duplicate</code>] <code>lb-add</code> <var>lb</var> <var>vip</var> <var>ips</var> [<var>protocol</var>]</dt>
> > +        <dt>[<code>--may-exist</code> | <code>--add-duplicate</code> | <code>--reject</code>] <code>lb-add</code> <var>lb</var> <var>vip</var> <var>ips</var> [<var>protocol</var>]</dt>
> >         <dd>
> >           <p>
> >            Creates a new load balancer named <var>lb</var> with the provided
> > @@ -936,6 +936,15 @@
> >            creates a new load balancer with a duplicate name.
> >           </p>
> >
> > +        <p>
> > +         If the load balancer is created with <code>--reject</code> option and
> > +         it has no active backends, a TCP reset segment (for tcp) or an ICMP
> > +         port unreachable packet (for all other kind of traffic) will be sent
> > +         whenever an incoming packet is received for this load-balancer.
> > +         Please note using <code>--reject</code> option will disable
> > +         empty_lb SB controller event for this load balancer.
> > +        </p>
> > +
> >           <p>
> >            The following example adds a load balancer.
> >           </p>
> > diff --git a/utilities/ovn-nbctl.c b/utilities/ovn-nbctl.c
> > index d19e1b6c6..3a95f6b1f 100644
> > --- a/utilities/ovn-nbctl.c
> > +++ b/utilities/ovn-nbctl.c
> > @@ -2821,6 +2821,7 @@ nbctl_lb_add(struct ctl_context *ctx)
> >
> >       bool may_exist = shash_find(&ctx->options, "--may-exist") != NULL;
> >       bool add_duplicate = shash_find(&ctx->options, "--add-duplicate") != NULL;
> > +    bool empty_backend_rej = shash_find(&ctx->options, "--reject") != NULL;
> >
> >       const char *lb_proto;
> >       bool is_update_proto = false;
> > @@ -2934,6 +2935,10 @@ nbctl_lb_add(struct ctl_context *ctx)
> >       smap_add(CONST_CAST(struct smap *, &lb->vips),
> >               lb_vip_normalized, ds_cstr(&lb_ips_new));
> >       nbrec_load_balancer_set_vips(lb, &lb->vips);
> > +    if (empty_backend_rej) {
> > +        const struct smap options = SMAP_CONST1(&options, "reject", "true");
> > +        nbrec_load_balancer_set_options(lb, &options);
> > +    }
> >   out:
> >       ds_destroy(&lb_ips_new);
> >
> > @@ -6588,7 +6593,7 @@ static const struct ctl_command_syntax nbctl_commands[] = {
> >         nbctl_lr_nat_set_ext_ips, NULL, "--is-exempted", RW},
> >       /* load balancer commands. */
> >       { "lb-add", 3, 4, "LB VIP[:PORT] IP[:PORT]... [PROTOCOL]", NULL,
> > -      nbctl_lb_add, NULL, "--may-exist,--add-duplicate", RW },
> > +      nbctl_lb_add, NULL, "--may-exist,--add-duplicate,--reject", RW },
> >       { "lb-del", 1, 2, "LB [VIP]", NULL, nbctl_lb_del, NULL,
> >           "--if-exists", RW },
> >       { "lb-list", 0, 1, "[LB]", NULL, nbctl_lb_list, NULL, "", RO },
> >
>
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