[ovs-dev,v7] northd: Routing protocol port redirection.

This change adds two new LRP options:
 * routing-protocol-redirect
 * routing-protocols

These allow redirection of a routing protocol traffic to
an Logical Switch Port. This enables external routing daemons
to listen on an interface bound to an LSP and effectively act
as if they were listening on (and speaking from) LRP's IP address.

Option 'routing-protocols' takes a comma-separated list of routing
protocols whose traffic should be redirected. Currently supported
are BGP (tcp 179) and BFD (udp 3784).

Option 'routing-protocol-redirect' expects a string with an LSP
name.

When both of these options are set, any traffic entering LS
that's destined for LRP's IP addresses (including IPv6 LLA) and
routing protocol's port number, is redirected to the LSP specified
in the 'routing-protocol-redirect' value.

NOTE: this feature is experimental and may be subject to
removal/change in the future.

Signed-off-by: Martin Kalcok <martin.kalcok@canonical.com>
---
 
 I'm posting this v7 patch just as a preview. northd occasionally
 crashes in the added datapath tests. It's an issue I can't seem to
 reproduce in my test deployment, only during the tests. Until that's
 resolved, this patch is not suitable for merging.

 Compared to v6, this patch includes:
 Fix for cloning of ARP/ND messages. Now the messages are
 properly delivered to both, redirect port and the LRP.

 It also adds functional test that verifies ability of hosts on
 internal networks to communicate with the external networks
 uninterupted, even when the worwarding is enabled


 northd/northd.c         | 225 ++++++++++++++++++++++++++++++++++++++++
 northd/northd.h         |   7 ++
 northd/ovn-northd.8.xml |  54 ++++++++++
 ovn-nb.xml              |  42 ++++++++
 tests/ovn-northd.at     |  93 +++++++++++++++++
 tests/system-ovn.at     | 120 +++++++++++++++++++++
 6 files changed, 541 insertions(+)

On Fri, Aug 9, 2024 at 2:42 PM Martin Kalcok
<martin.kalcok@canonical.com> wrote:
>
> This change adds two new LRP options:
>  * routing-protocol-redirect
>  * routing-protocols
>
> These allow redirection of a routing protocol traffic to
> an Logical Switch Port. This enables external routing daemons
> to listen on an interface bound to an LSP and effectively act
> as if they were listening on (and speaking from) LRP's IP address.
>
> Option 'routing-protocols' takes a comma-separated list of routing
> protocols whose traffic should be redirected. Currently supported
> are BGP (tcp 179) and BFD (udp 3784).
>
> Option 'routing-protocol-redirect' expects a string with an LSP
> name.
>
> When both of these options are set, any traffic entering LS
> that's destined for LRP's IP addresses (including IPv6 LLA) and
> routing protocol's port number, is redirected to the LSP specified
> in the 'routing-protocol-redirect' value.
>
> NOTE: this feature is experimental and may be subject to
> removal/change in the future.
>
> Signed-off-by: Martin Kalcok <martin.kalcok@canonical.com>

Hi Martin,

Looks like you need to rebase.

Numan

> ---
>
>  I'm posting this v7 patch just as a preview. northd occasionally
>  crashes in the added datapath tests. It's an issue I can't seem to
>  reproduce in my test deployment, only during the tests. Until that's
>  resolved, this patch is not suitable for merging.
>
>  Compared to v6, this patch includes:
>  Fix for cloning of ARP/ND messages. Now the messages are
>  properly delivered to both, redirect port and the LRP.
>
>  It also adds functional test that verifies ability of hosts on
>  internal networks to communicate with the external networks
>  uninterupted, even when the worwarding is enabled
>
>
>  northd/northd.c         | 225 ++++++++++++++++++++++++++++++++++++++++
>  northd/northd.h         |   7 ++
>  northd/ovn-northd.8.xml |  54 ++++++++++
>  ovn-nb.xml              |  42 ++++++++
>  tests/ovn-northd.at     |  93 +++++++++++++++++
>  tests/system-ovn.at     | 120 +++++++++++++++++++++
>  6 files changed, 541 insertions(+)
>
> diff --git a/northd/northd.c b/northd/northd.c
> index 0c73e70df..9f2fd5278 100644
> --- a/northd/northd.c
> +++ b/northd/northd.c
> @@ -13935,6 +13935,229 @@ build_arp_resolve_flows_for_lrp(struct ovn_port *op,
>      }
>  }
>
> +static void
> +build_routing_protocols_redirect_rule__(
> +        const char *s_addr, const char *redirect_port_name, int protocol_port,
> +        const char *proto, bool is_ipv6, struct ovn_port *ls_peer,
> +        struct lflow_table *lflows, struct ds *match, struct ds *actions)
> +{
> +    int ip_ver = is_ipv6 ? 6 : 4;
> +    ds_clear(actions);
> +    ds_put_format(actions, "outport = \"%s\"; output;", redirect_port_name);
> +
> +    /* Redirect packets in the input pipeline destined for LR's IP
> +     * and the routing protocol's port to the LSP specified in
> +     * 'routing-protocol-redirect' option.*/
> +    ds_clear(match);
> +    ds_put_format(match, "ip%d.dst == %s && %s.dst == %d", ip_ver, s_addr,
> +                  proto, protocol_port);
> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                  ds_cstr(match),
> +                  ds_cstr(actions),
> +                  ls_peer->lflow_ref);
> +
> +    /* To accomodate "peer" nature of the routing daemons, redirect also
> +     * replies to the daemons' client requests. */
> +    ds_clear(match);
> +    ds_put_format(match, "ip%d.dst == %s && %s.src == %d", ip_ver, s_addr,
> +                  proto, protocol_port);
> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                  ds_cstr(match),
> +                  ds_cstr(actions),
> +                  ls_peer->lflow_ref);
> +}
> +
> +static void
> +apply_routing_protocols_redirect__(
> +        const char *s_addr, const char *redirect_port_name, int protocol_flags,
> +        bool is_ipv6, struct ovn_port *ls_peer, struct lflow_table *lflows,
> +        struct ds *match, struct ds *actions)
> +{
> +    if (protocol_flags & REDIRECT_BGP) {
> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
> +                                                179, "tcp", is_ipv6, ls_peer,
> +                                                lflows, match, actions);
> +    }
> +
> +    if (protocol_flags & REDIRECT_BFD) {
> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
> +                                                3784, "udp", is_ipv6, ls_peer,
> +                                                lflows, match, actions);
> +    }
> +
> +    /* Because the redirected port shares IP and MAC addresses with the LRP,
> +     * special consideration needs to be given to the signaling protocols. */
> +    if (is_ipv6) {
> +        /* Ensure that redirect port receives copy of NA messages destined to
> +         * its IP.*/
> +        ds_clear(match);
> +        ds_clear(actions);
> +        ds_put_format(actions,
> +                     "clone { outport = \"%s\"; output; }; "
> +                     "outport = %s; output;",
> +                      redirect_port_name, ls_peer->json_key);
> +        ds_put_format(match, "ip6.dst == %s && nd_na", s_addr);
> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                      ds_cstr(match),
> +                      ds_cstr(actions),
> +                      ls_peer->lflow_ref);
> +    } else {
> +        /* Ensure that redirect port receives copy of ARP replies destined to
> +         * its IP */
> +        ds_clear(match);
> +        ds_clear(actions);
> +        ds_put_format(actions,
> +                      "clone { outport = \"%s\"; output; }; "
> +                      "outport = %s; output;",
> +                      redirect_port_name, ls_peer->json_key);
> +        ds_put_format(match, "arp.op == 2 && arp.tpa == %s", s_addr);
> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                      ds_cstr(match),
> +                      ds_cstr(actions),
> +                      ls_peer->lflow_ref);
> +    }
> +}
> +
> +static int
> +parse_redirected_routing_protocols(struct ovn_port *lrp) {
> +    int redirected_protocol_flags = 0;
> +    const char *redirect_protocols = smap_get(&lrp->nbrp->options,
> +                                              "routing-protocols");
> +    if (redirect_protocols == NULL) {
> +        return redirected_protocol_flags;
> +    }
> +
> +    char *proto;
> +    char *save_ptr = NULL;
> +    char *tokstr = xstrdup(redirect_protocols);
> +    for (proto = strtok_r(tokstr, ",", &save_ptr); proto != NULL;
> +         proto = strtok_r(NULL, ",", &save_ptr)) {
> +        if (!strcmp(proto, "BGP")) {
> +            redirected_protocol_flags |= REDIRECT_BGP;
> +            continue;
> +        }
> +
> +        if (!strcmp(proto, "BFD")) {
> +            redirected_protocol_flags |= REDIRECT_BFD;
> +            continue;
> +        }
> +
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocols' encountered unknown "
> +                          "value %s",
> +                          proto);
> +    }
> +    free(tokstr);
> +    return redirected_protocol_flags;
> +}
> +
> +static void
> +build_lrouter_routing_protocol_redirect(
> +        struct ovn_port *op, struct lflow_table *lflows,
> +        struct ds *match, struct ds *actions)
> +{
> +    /* LRP has to have a peer.*/
> +    if (op->peer == NULL) {
> +        return;
> +    }
> +
> +    /* LRP has to have NB record.*/
> +    if (op->nbrp == NULL) {
> +        return;
> +    }
> +
> +    /* Proceed only for LRPs that have 'routing-protocol-redirect' option set.
> +     * Value of this option is the name of LSP to which the routing protocol
> +     * traffic will be redirected. */
> +    const char *redirect_port = smap_get(&op->nbrp->options,
> +                                         "routing-protocol-redirect");
> +    if (redirect_port == NULL) {
> +        return;
> +    }
> +
> +    if (op->cr_port != NULL) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is not "
> +                          "supported on Distributed Gateway Port '%s'",
> +                          op->key);
> +        return;
> +    }
> +
> +    /* Ensure that LSP, to which the routing protocol traffic is redirected,
> +     * exists. */
> +    struct ovn_port *peer_lsp;
> +    bool redirect_port_exists = false;
> +    HMAP_FOR_EACH (peer_lsp, dp_node, &op->peer->od->ports) {
> +        size_t peer_lsp_s = strlen(peer_lsp->key);
> +        if (peer_lsp_s == strlen(redirect_port)
> +            && !strncmp(peer_lsp->key, redirect_port, peer_lsp_s)){
> +            redirect_port_exists = true;
> +            break;
> +        }
> +    }
> +
> +    if (!redirect_port_exists) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' set on Logical "
> +                          "Router Port '%s' refers to non-existent Logical "
> +                          "Switch Port. Routing protocol redirecting won't be "
> +                          "configured.",
> +                          op->key);
> +        return;
> +    }
> +
> +    int redirected_protocols = parse_redirected_routing_protocols(op);
> +    if (!redirected_protocols) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is set on "
> +                          "Logical Router Port '%s' but no known protocols "
> +                          "were set via 'routing-protocols' options. This "
> +                          "configuration has no effect.",
> +                          op->key);
> +        return;
> +    }
> +
> +    /* Redirected traffic destined for LRP's IPs and the specified routing
> +     * protocol ports to the port defined in 'routing-protocol-redirect'
> +     * option.*/
> +    for (size_t i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
> +        const char *ip_s = op->lrp_networks.ipv4_addrs[i].addr_s;
> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> +                                           redirected_protocols, false,
> +                                           op->peer, lflows,match, actions);
> +    }
> +    for (size_t i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
> +        const char *ip_s = op->lrp_networks.ipv6_addrs[i].addr_s;
> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> +                                           redirected_protocols, true,
> +                                           op->peer, lflows,match, actions);
> +    }
> +
> +    /* Drop ARP replies and IPv6 RA/NA packets originating from
> +     * 'routing-protocol-redirect' LSP. As this port shares IP and MAC
> +     * addresses with LRP, we don't want to create duplicates.*/
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && arp.op == 2", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && nd_na", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && nd_ra", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +}
> +
>  /* This function adds ARP resolve flows related to a LSP. */
>  static void
>  build_arp_resolve_flows_for_lsp(
> @@ -16900,6 +17123,8 @@ build_lswitch_and_lrouter_iterate_by_lrp(struct ovn_port *op,
>                                  op->lflow_ref);
>      build_lrouter_icmp_packet_toobig_admin_flows(op, lsi->lflows, &lsi->match,
>                                                   &lsi->actions, op->lflow_ref);
> +    build_lrouter_routing_protocol_redirect(op, lsi->lflows,
> +                                            &lsi->match, &lsi->actions);
>  }
>
>  static void *
> diff --git a/northd/northd.h b/northd/northd.h
> index e04ec5856..9e326b746 100644
> --- a/northd/northd.h
> +++ b/northd/northd.h
> @@ -93,6 +93,13 @@ ovn_datapath_find_by_key(struct hmap *datapaths, uint32_t dp_key);
>
>  bool od_has_lb_vip(const struct ovn_datapath *od);
>
> +/* List of routing and routing-related protocols which
> + * OVN is capable of redirecting from LRP to specific LSP. */
> +enum redirected_routing_protcol_flag_type {
> +    REDIRECT_BGP = (1 << 0),
> +    REDIRECT_BFD = (1 << 1),
> +};
> +
>  struct tracked_ovn_ports {
>      /* tracked created ports.
>       * hmapx node data is 'struct ovn_port *' */
> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> index 3abd5f75b..ede38882a 100644
> --- a/northd/ovn-northd.8.xml
> +++ b/northd/ovn-northd.8.xml
> @@ -284,6 +284,32 @@
>          dropped in the next stage.
>        </li>
>
> +      <li>
> +        <p>
> +          For each logical port that's defined as a target of routing protocol
> +          redirecting (via <code>routing-protocol-redirect</code> option set on
> +          Logical Router Port), a filter is set in place that disallows
> +          following traffic exiting this port:
> +        </p>
> +        <ul>
> +          <li>
> +            ARP replies
> +          </li>
> +          <li>
> +            IPv6 Neighbor Discovery - Router Advertisements
> +          </li>
> +          <li>
> +            IPv6 Neighbor Discovery - Neighbor Advertisements
> +          </li>
> +        </ul>
> +        <p>
> +          Since this port shares IP and MAC addresses with the Logical Router
> +          Port, we wan't to prevent duplicate replies and advertisements. This
> +          is achieved by a rule with priority 80 that sets
> +          <code>REGBIT_PORT_SEC_DROP" = 1; next;"</code>.
> +        </p>
> +      </li>
> +
>        <li>
>          For each (enabled) vtep logical port, a priority 70 flow is added which
>          matches on all packets and applies the action
> @@ -2002,6 +2028,34 @@ output;
>          on the logical switch.
>        </li>
>
> +      <li>
> +        <p>
> +          For any logical port that's defined as a target of routing protocol
> +          redirecting (via <code>routing-protocol-redirect</code> option set on
> +          Logical Router Port), we redirect the traffic related to protocols
> +          specified in <code>routing-protocols</code> option. It's acoomplished
> +          with following priority-100 flows:
> +        </p>
> +        <ul>
> +          <li>
> +            Flows that match Logical Router Port's IPs and destination port of
> +            the routing daemon are redirected to this port to allow external
> +            peers' connection to the daemon listening on this port.
> +          </li>
> +          <li>
> +            Flows that match Logical Router Port's IPs and source port of
> +            the routing daemon are redirected to this port to allow replies
> +            from the peers.
> +          </li>
> +        </ul>
> +        <p>
> +          In addition to this, we add priority-100 rules that
> +          <code>clone</code> ARP replies and IPv6 Neighbor Advertisements to
> +          this port as well. These allow to build proper ARP/IPv6 neighbor
> +          list on this port.
> +        </p>
> +      </li>
> +
>        <li>
>          Priority-90 flows for transit switches that forward registered
>          IP multicast traffic to their corresponding multicast group , which
> diff --git a/ovn-nb.xml b/ovn-nb.xml
> index bbda423a5..2836f58f5 100644
> --- a/ovn-nb.xml
> +++ b/ovn-nb.xml
> @@ -3575,6 +3575,48 @@ or
>          </p>
>        </column>
>
> +      <column name="options" key="routing-protocol-redirect"
> +              type='{"type": "string"}'>
> +        <p>
> +          NOTE: this feature is experimental and may be subject to
> +          removal/change in the future.
> +        </p>
> +        <p>
> +          This option expects a name of a Logical Switch Port that's present
> +          in the peer's Logical Switch. If set, it causes any traffic
> +          that's destined for Logical Router Port's IP addresses (including
> +          its IPv6 LLA) and the ports associated with routing protocols defined
> +          ip <code>routing-protocols</code> option, to be redirected
> +          to the specified Logical Switch Port.
> +
> +          This allows external routing daemons to be bound to a port in OVN's
> +          Logical Switch and act as if they were listening on Logical Router
> +          Port's IP addresses.
> +        </p>
> +      </column>
> +
> +      <column name="options" key="routing-protocols" type='{"type": "string"}'>
> +        <p>
> +          NOTE: this feature is experimental and may be subject to
> +          removal/change in the future.
> +        </p>
> +        <p>
> +          This option expects a comma-separated list of routing, and
> +          routing-related protocols, whose control plane traffic will be
> +          redirected to a port specified in
> +          <code>routing-protocol-redirect</code> option. Currently supported
> +          options are:
> +        </p>
> +        <ul>
> +          <li>
> +            <code>BGP</code> (forwards TCP port 179)
> +          </li>
> +          <li>
> +            <code>BFD</code> (forwards UDP port 3784)
> +          </li>
> +        </ul>
> +      </column>
> +
>        <column name="options" key="gateway_mtu_bypass">
>          <p>
>            When configured, represents a match expression, in the same
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index f2f42275a..bd05da3cd 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -13757,3 +13757,96 @@ AT_CHECK([grep -e "172.168.0.110" -e "172.168.0.120" -e "10.0.0.3" -e "20.0.0.3"
>
>  AT_CLEANUP
>  ])
> +
> +OVN_FOR_EACH_NORTHD_NO_HV([
> +AT_SETUP([Routing protocol control plane redirect])
> +ovn_start
> +
> +check ovn-sbctl chassis-add hv1 geneve 127.0.0.1
> +
> +check ovn-nbctl lr-add lr -- \
> +    lrp-add lr lr-ls 02:ac:10:01:00:01 172.16.1.1/24
> +check ovn-nbctl --wait=sb set logical_router lr options:chassis=hv1
> +
> +check ovn-nbctl ls-add ls -- \
> +    lsp-add ls ls-lr -- \
> +    lsp-set-type ls-lr router -- \
> +    lsp-set-addresses ls-lr router -- \
> +    lsp-set-options ls-lr router-port=lr-ls
> +
> +check ovn-nbctl lsp-add ls lsp-bgp -- \
> +    lsp-set-addresses lsp-bgp unknown
> +
> +# Function that ensures that no redirect rules are installed.
> +check_no_redirect() {
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "tcp.dst == 179|tcp.src == 179" | wc -l], [0], [0
> +])
> +
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep -E "priority=80" | wc -l], [0], [0
> +])
> +    check_no_bfd_redirect
> +}
> +
> +# Function that ensures that no BFD redirect rules are installed.
> +check_no_bfd_redirect() {
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "udp.dst == 3784|udp.src == 3784" | wc -l], [0], [0
> +])
> +}
> +
> +# By default, no rules related to routing protocol redirect are present
> +check_no_redirect
> +
> +# Set "lsp-bgp" port as target of BGP control plane redirected traffic
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-bgp
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP
> +
> +# Check that BGP control plane traffic is redirected "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "tcp.dst == 179|tcp.src == 179" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
> +])
> +
> +# Check that ARP/ND traffic is cloned to the "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "arp.op == 2 && arp.tpa == 172.16.1.1" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(arp.op == 2 && arp.tpa == 172.16.1.1), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
> +])
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "&& nd_na" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && nd_na), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
> +])
> +
> +# Check that at this point no BFD redirecting is present
> +check_no_bfd_redirect
> +
> +# Add BFD traffic redirect
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
> +
> +# Check that BFD traffic is redirected to "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "udp.dst == 3784|udp.src == 3784" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
> +])
> +
> +
> +# Check that ARP replies and ND advertisements are blocked from exiting "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep "priority=80" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && arp.op == 2), action=(reg0[[15]] = 1; next;)
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_na), action=(reg0[[15]] = 1; next;)
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_ra), action=(reg0[[15]] = 1; next;)
> +])
> +
> +# Remove 'bgp-redirect' option from LRP and check that rules are removed
> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocol-redirect
> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocols
> +check_no_redirect
> +
> +# Set non-existent LSP as target of 'bgp-redirect' and check that no rules are added
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-foo
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
> +check_no_redirect
> +
> +AT_CLEANUP
> +])
> diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> index 7ba2e150b..c0adb8cc2 100644
> --- a/tests/system-ovn.at
> +++ b/tests/system-ovn.at
> @@ -13504,3 +13504,123 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/failed to query port patch-.*/d
>
>  AT_CLEANUP
>  ])
> +
> +OVN_FOR_EACH_NORTHD([
> +AT_SETUP([Routing protocol redirect])
> +AT_SKIP_IF([test $HAVE_NC = no])
> +
> +ovn_start
> +OVS_TRAFFIC_VSWITCHD_START()
> +
> +ADD_BR([br-int])
> +ADD_BR([br-ext])
> +
> +check ovs-ofctl add-flow br-ext action=normal
> +# Set external-ids in br-int needed for ovn-controller
> +check ovs-vsctl \
> +        -- set Open_vSwitch . external-ids:system-id=hv1 \
> +        -- set Open_vSwitch . external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
> +        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
> +        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
> +        -- set bridge br-int fail-mode=secure other-config:disable-in-band=true
> +
> +# Start ovn-controller
> +start_daemon ovn-controller
> +
> +check ovn-nbctl lr-add R1 \
> +    -- set Logical_Router R1 options:chassis=hv1
> +
> +check ovn-nbctl ls-add public
> +check ovn-nbctl ls-add bar
> +
> +check ovn-nbctl lrp-add R1 rp-public 00:00:02:01:02:03 172.16.1.1/24
> +check ovn-nbctl lrp-add R1 rp-bar 00:00:ff:00:00:01 192.168.10.1/24
> +
> +check ovn-nbctl lsp-add public public-rp -- set Logical_Switch_Port public-rp \
> +    type=router options:router-port=rp-public \
> +    -- lsp-set-addresses public-rp router
> +
> +check ovn-nbctl lsp-add bar bar-rp -- set Logical_Switch_Port bar-rp \
> +    type=router options:router-port=rp-bar \
> +    -- lsp-set-addresses bar-rp router
> +
> +check ovn-nbctl lsp-add public bgp-daemon \
> +    -- lsp-set-addresses bgp-daemon unknown
> +
> +# Setup container "bar1" representing host on an internal network
> +ADD_NAMESPACES(bar1)
> +ADD_VETH(bar1, bar1, br-int, "192.168.10.2/24", "00:00:ff:ff:ff:01", \
> +         "192.168.10.1")
> +check ovn-nbctl lsp-add bar bar1 \
> +    -- lsp-set-addresses bar1 "00:00:ff:ff:ff:01 192.168.10.2"
> +
> +# Setup SNAT for the internal host
> +AT_CHECK([ovn-nbctl lr-nat-add R1 snat 172.16.1.1 192.168.10.2])
> +
> +# Configure external connectivity
> +AT_CHECK([ovs-vsctl set Open_vSwitch . external-ids:ovn-bridge-mappings=phynet:br-ext])
> +check ovn-nbctl lsp-add public public1 \
> +        -- lsp-set-addresses public1 unknown \
> +        -- lsp-set-type public1 localnet \
> +        -- lsp-set-options public1 network_name=phynet
> +
> +check ovn-nbctl --wait=hv sync
> +
> +# Set option that redirects BGP traffic to a LSP "bgp-daemon"
> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocol-redirect=bgp-daemon
> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocols=BGP
> +
> +# Create "bgp-daemon" interface in a namespace with IP and MAC matching LRP "rp-public"
> +ADD_NAMESPACES(bgp-daemon)
> +ADD_VETH(bgp-daemon, bgp-daemon, br-int, "172.16.1.1/24", "00:00:02:01:02:03")
> +
> +ADD_NAMESPACES(ext-foo)
> +ADD_VETH(ext-foo, ext-foo, br-ext, "172.16.1.100/24", "00:10:10:01:02:13", \
> +         "172.16.1.1")
> +
> +# Flip the interface down/up to get proper IPv6 LLA
> +NS_EXEC([bgp-daemon], [ip link set down bgp-daemon])
> +NS_EXEC([bgp-daemon], [ip link set up bgp-daemon])
> +NS_EXEC([ext-foo], [ip link set down ext-foo])
> +NS_EXEC([ext-foo], [ip link set up ext-foo])
> +
> +# Wait until IPv6 LLA loses the "tentative" flag otherwise it can't be bound to.
> +OVS_WAIT_UNTIL([NS_EXEC([bgp-daemon], [ip a show dev bgp-daemon | grep "fe80::" | grep -v tentative])])
> +OVS_WAIT_UNTIL([NS_EXEC([ext-foo], [ip a show dev ext-foo | grep "fe80::" | grep -v tentative])])
> +
> +# Verify that BGP control plane traffic is delivered to the "bgp-daemon"
> +# interface on both IPv4 and IPv6 LLA addresses
> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -k 172.16.1.1 179], [bgp_v4.pid])
> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only 172.16.1.1 179])
> +
> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -6 -k fe80::200:2ff:fe01:203%bgp-daemon 179], [bgp_v6.pid])
> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only -6 fe80::200:2ff:fe01:203%ext-foo 179])
> +
> +# Verify connection in other direction. i.e when daemon running on "bgp-daemon" port
> +# makes a client connection to its peer
> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 179], [reply_bgp_v4.pid])
> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only 172.16.1.100 179])
> +
> +NETNS_DAEMONIZE([ext-foo], [nc -l -6 -k fe80::210:10ff:fe01:213%ext-foo 179], [reply_bgp_v6.pid])
> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only -6 fe80::210:10ff:fe01:213%bgp-daemon 179])
> +
> +# Verify that hosts on the internal network can reach external networks
> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 2222], [nc_external.pid])
> +NS_CHECK_EXEC([bar1], [echo "TCP test" | nc -w 1 --send-only 172.16.1.100 2222])
> +
> +OVS_APP_EXIT_AND_WAIT([ovn-controller])
> +
> +as ovn-sb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as ovn-nb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as northd
> +OVS_APP_EXIT_AND_WAIT([ovn-northd])
> +
> +as
> +OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
> +/.*terminating with signal 15.*/d"])
> +AT_CLEANUP
> +])
> --
> 2.43.0
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>

On Fri, 2024-08-09 at 15:11 -0400, Numan Siddique wrote:
> On Fri, Aug 9, 2024 at 2:42 PM Martin Kalcok
> <martin.kalcok@canonical.com> wrote:
> > 
> > This change adds two new LRP options:
> >  * routing-protocol-redirect
> >  * routing-protocols
> > 
> > These allow redirection of a routing protocol traffic to
> > an Logical Switch Port. This enables external routing daemons
> > to listen on an interface bound to an LSP and effectively act
> > as if they were listening on (and speaking from) LRP's IP address.
> > 
> > Option 'routing-protocols' takes a comma-separated list of routing
> > protocols whose traffic should be redirected. Currently supported
> > are BGP (tcp 179) and BFD (udp 3784).
> > 
> > Option 'routing-protocol-redirect' expects a string with an LSP
> > name.
> > 
> > When both of these options are set, any traffic entering LS
> > that's destined for LRP's IP addresses (including IPv6 LLA) and
> > routing protocol's port number, is redirected to the LSP specified
> > in the 'routing-protocol-redirect' value.
> > 
> > NOTE: this feature is experimental and may be subject to
> > removal/change in the future.
> > 
> > Signed-off-by: Martin Kalcok <martin.kalcok@canonical.com>
> 
> Hi Martin,
> 
> Looks like you need to rebase.
> 
> Numan
Hi Numan,
Thanks for the advice. The CI is suspiciously passing [0]. However I
still see it crashing occasionally when I run tests on my host. I'll
try to setup a fresh test host, in case something unclean was left
behind.
Following is the tail end of the northd log under test when it crashes
(in case it rings any bells):

2024-08-
09T19:30:42.428Z|00154|jsonrpc|DBG|unix:/root/build_area/ovn/tests/syst
em-userspace-testsuite.dir/184/ovn-nb/ovn-nb.sock: received
notification, method="update3",
params=[["monid","OVN_Northbound"],"00000000-0000-0000-0000-
000000000000",{"Logical_Switch_Port":{"5fff6eea-79cd-40fb-a627-
83aaa68ea1d5":{"modify":{"up":true}}}}]
2024-08-
09T19:30:42.428Z|00155|jsonrpc|DBG|unix:/root/build_area/ovn/tests/syst
em-userspace-testsuite.dir/184/ovn-nb/ovn-nb.sock: received reply,
result=[{"count":1},{}], id=44
SIGSEGV detected, backtrace:
ovn-northd(+0x185396)[0x5f3c4b18c396]
ovn-northd(+0xeeacf)[0x5f3c4b0f5acf]
/lib/x86_64-linux-gnu/libc.so.6(+0x45320)[0x71b72a245320]
ovn-northd(+0x720a5)[0x5f3c4b0790a5]
ovn-northd(+0x74398)[0x5f3c4b07b398]
ovn-northd(+0x65642)[0x5f3c4b06c642]
ovn-northd(+0x7cf45)[0x5f3c4b083f45]
ovn-northd(+0x7da18)[0x5f3c4b084a18]
ovn-northd(+0x70a09)[0x5f3c4b077a09]
ovn-northd(+0x34d11)[0x5f3c4b03bd11]
/lib/x86_64-linux-gnu/libc.so.6(+0x2a1ca)[0x71b72a22a1ca]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x8b)[0x71b72a22a28b]
ovn-northd(+0x36755)[0x5f3c4b03d755]
2024-08-
09T19:30:42.429Z|00001|fatal_signal(stopwatch0)|WARN|terminating with
signal 11 (Segmentation fault)

[0]https://github.com/mkalcok/ovn/actions/runs/10324636909/job/28584638332

Thanks,
Martin.
> 
> > ---
> > 
> >  I'm posting this v7 patch just as a preview. northd occasionally
> >  crashes in the added datapath tests. It's an issue I can't seem to
> >  reproduce in my test deployment, only during the tests. Until
> > that's
> >  resolved, this patch is not suitable for merging.
> > 
> >  Compared to v6, this patch includes:
> >  Fix for cloning of ARP/ND messages. Now the messages are
> >  properly delivered to both, redirect port and the LRP.
> > 
> >  It also adds functional test that verifies ability of hosts on
> >  internal networks to communicate with the external networks
> >  uninterupted, even when the worwarding is enabled
> > 
> > 
> >  northd/northd.c         | 225
> > ++++++++++++++++++++++++++++++++++++++++
> >  northd/northd.h         |   7 ++
> >  northd/ovn-northd.8.xml |  54 ++++++++++
> >  ovn-nb.xml              |  42 ++++++++
> >  tests/ovn-northd.at     |  93 +++++++++++++++++
> >  tests/system-ovn.at     | 120 +++++++++++++++++++++
> >  6 files changed, 541 insertions(+)
> > 
> > diff --git a/northd/northd.c b/northd/northd.c
> > index 0c73e70df..9f2fd5278 100644
> > --- a/northd/northd.c
> > +++ b/northd/northd.c
> > @@ -13935,6 +13935,229 @@ build_arp_resolve_flows_for_lrp(struct
> > ovn_port *op,
> >      }
> >  }
> > 
> > +static void
> > +build_routing_protocols_redirect_rule__(
> > +        const char *s_addr, const char *redirect_port_name, int
> > protocol_port,
> > +        const char *proto, bool is_ipv6, struct ovn_port *ls_peer,
> > +        struct lflow_table *lflows, struct ds *match, struct ds
> > *actions)
> > +{
> > +    int ip_ver = is_ipv6 ? 6 : 4;
> > +    ds_clear(actions);
> > +    ds_put_format(actions, "outport = \"%s\"; output;",
> > redirect_port_name);
> > +
> > +    /* Redirect packets in the input pipeline destined for LR's IP
> > +     * and the routing protocol's port to the LSP specified in
> > +     * 'routing-protocol-redirect' option.*/
> > +    ds_clear(match);
> > +    ds_put_format(match, "ip%d.dst == %s && %s.dst == %d", ip_ver,
> > s_addr,
> > +                  proto, protocol_port);
> > +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> > +                  ds_cstr(match),
> > +                  ds_cstr(actions),
> > +                  ls_peer->lflow_ref);
> > +
> > +    /* To accomodate "peer" nature of the routing daemons,
> > redirect also
> > +     * replies to the daemons' client requests. */
> > +    ds_clear(match);
> > +    ds_put_format(match, "ip%d.dst == %s && %s.src == %d", ip_ver,
> > s_addr,
> > +                  proto, protocol_port);
> > +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> > +                  ds_cstr(match),
> > +                  ds_cstr(actions),
> > +                  ls_peer->lflow_ref);
> > +}
> > +
> > +static void
> > +apply_routing_protocols_redirect__(
> > +        const char *s_addr, const char *redirect_port_name, int
> > protocol_flags,
> > +        bool is_ipv6, struct ovn_port *ls_peer, struct lflow_table
> > *lflows,
> > +        struct ds *match, struct ds *actions)
> > +{
> > +    if (protocol_flags & REDIRECT_BGP) {
> > +        build_routing_protocols_redirect_rule__(s_addr,
> > redirect_port_name,
> > +                                                179, "tcp",
> > is_ipv6, ls_peer,
> > +                                                lflows, match,
> > actions);
> > +    }
> > +
> > +    if (protocol_flags & REDIRECT_BFD) {
> > +        build_routing_protocols_redirect_rule__(s_addr,
> > redirect_port_name,
> > +                                                3784, "udp",
> > is_ipv6, ls_peer,
> > +                                                lflows, match,
> > actions);
> > +    }
> > +
> > +    /* Because the redirected port shares IP and MAC addresses
> > with the LRP,
> > +     * special consideration needs to be given to the signaling
> > protocols. */
> > +    if (is_ipv6) {
> > +        /* Ensure that redirect port receives copy of NA messages
> > destined to
> > +         * its IP.*/
> > +        ds_clear(match);
> > +        ds_clear(actions);
> > +        ds_put_format(actions,
> > +                     "clone { outport = \"%s\"; output; }; "
> > +                     "outport = %s; output;",
> > +                      redirect_port_name, ls_peer->json_key);
> > +        ds_put_format(match, "ip6.dst == %s && nd_na", s_addr);
> > +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP,
> > 100,
> > +                      ds_cstr(match),
> > +                      ds_cstr(actions),
> > +                      ls_peer->lflow_ref);
> > +    } else {
> > +        /* Ensure that redirect port receives copy of ARP replies
> > destined to
> > +         * its IP */
> > +        ds_clear(match);
> > +        ds_clear(actions);
> > +        ds_put_format(actions,
> > +                      "clone { outport = \"%s\"; output; }; "
> > +                      "outport = %s; output;",
> > +                      redirect_port_name, ls_peer->json_key);
> > +        ds_put_format(match, "arp.op == 2 && arp.tpa == %s",
> > s_addr);
> > +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP,
> > 100,
> > +                      ds_cstr(match),
> > +                      ds_cstr(actions),
> > +                      ls_peer->lflow_ref);
> > +    }
> > +}
> > +
> > +static int
> > +parse_redirected_routing_protocols(struct ovn_port *lrp) {
> > +    int redirected_protocol_flags = 0;
> > +    const char *redirect_protocols = smap_get(&lrp->nbrp->options,
> > +                                              "routing-
> > protocols");
> > +    if (redirect_protocols == NULL) {
> > +        return redirected_protocol_flags;
> > +    }
> > +
> > +    char *proto;
> > +    char *save_ptr = NULL;
> > +    char *tokstr = xstrdup(redirect_protocols);
> > +    for (proto = strtok_r(tokstr, ",", &save_ptr); proto != NULL;
> > +         proto = strtok_r(NULL, ",", &save_ptr)) {
> > +        if (!strcmp(proto, "BGP")) {
> > +            redirected_protocol_flags |= REDIRECT_BGP;
> > +            continue;
> > +        }
> > +
> > +        if (!strcmp(proto, "BFD")) {
> > +            redirected_protocol_flags |= REDIRECT_BFD;
> > +            continue;
> > +        }
> > +
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1,
> > 5);
> > +        VLOG_WARN_RL(&rl, "Option 'routing-protocols' encountered
> > unknown "
> > +                          "value %s",
> > +                          proto);
> > +    }
> > +    free(tokstr);
> > +    return redirected_protocol_flags;
> > +}
> > +
> > +static void
> > +build_lrouter_routing_protocol_redirect(
> > +        struct ovn_port *op, struct lflow_table *lflows,
> > +        struct ds *match, struct ds *actions)
> > +{
> > +    /* LRP has to have a peer.*/
> > +    if (op->peer == NULL) {
> > +        return;
> > +    }
> > +
> > +    /* LRP has to have NB record.*/
> > +    if (op->nbrp == NULL) {
> > +        return;
> > +    }
> > +
> > +    /* Proceed only for LRPs that have 'routing-protocol-redirect'
> > option set.
> > +     * Value of this option is the name of LSP to which the
> > routing protocol
> > +     * traffic will be redirected. */
> > +    const char *redirect_port = smap_get(&op->nbrp->options,
> > +                                         "routing-protocol-
> > redirect");
> > +    if (redirect_port == NULL) {
> > +        return;
> > +    }
> > +
> > +    if (op->cr_port != NULL) {
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1,
> > 5);
> > +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is
> > not "
> > +                          "supported on Distributed Gateway Port
> > '%s'",
> > +                          op->key);
> > +        return;
> > +    }
> > +
> > +    /* Ensure that LSP, to which the routing protocol traffic is
> > redirected,
> > +     * exists. */
> > +    struct ovn_port *peer_lsp;
> > +    bool redirect_port_exists = false;
> > +    HMAP_FOR_EACH (peer_lsp, dp_node, &op->peer->od->ports) {
> > +        size_t peer_lsp_s = strlen(peer_lsp->key);
> > +        if (peer_lsp_s == strlen(redirect_port)
> > +            && !strncmp(peer_lsp->key, redirect_port,
> > peer_lsp_s)){
> > +            redirect_port_exists = true;
> > +            break;
> > +        }
> > +    }
> > +
> > +    if (!redirect_port_exists) {
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1,
> > 5);
> > +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' set
> > on Logical "
> > +                          "Router Port '%s' refers to non-existent
> > Logical "
> > +                          "Switch Port. Routing protocol
> > redirecting won't be "
> > +                          "configured.",
> > +                          op->key);
> > +        return;
> > +    }
> > +
> > +    int redirected_protocols =
> > parse_redirected_routing_protocols(op);
> > +    if (!redirected_protocols) {
> > +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1,
> > 5);
> > +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is
> > set on "
> > +                          "Logical Router Port '%s' but no known
> > protocols "
> > +                          "were set via 'routing-protocols'
> > options. This "
> > +                          "configuration has no effect.",
> > +                          op->key);
> > +        return;
> > +    }
> > +
> > +    /* Redirected traffic destined for LRP's IPs and the specified
> > routing
> > +     * protocol ports to the port defined in 'routing-protocol-
> > redirect'
> > +     * option.*/
> > +    for (size_t i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
> > +        const char *ip_s = op->lrp_networks.ipv4_addrs[i].addr_s;
> > +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> > +                                           redirected_protocols,
> > false,
> > +                                           op->peer, lflows,match,
> > actions);
> > +    }
> > +    for (size_t i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
> > +        const char *ip_s = op->lrp_networks.ipv6_addrs[i].addr_s;
> > +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> > +                                           redirected_protocols,
> > true,
> > +                                           op->peer, lflows,match,
> > actions);
> > +    }
> > +
> > +    /* Drop ARP replies and IPv6 RA/NA packets originating from
> > +     * 'routing-protocol-redirect' LSP. As this port shares IP and
> > MAC
> > +     * addresses with LRP, we don't want to create duplicates.*/
> > +    ds_clear(match);
> > +    ds_put_format(match, "inport == \"%s\" && arp.op == 2",
> > redirect_port);
> > +    ovn_lflow_add(lflows, op->peer->od,
> > S_SWITCH_IN_CHECK_PORT_SEC, 80,
> > +                  ds_cstr(match),
> > +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> > +                  op->peer->lflow_ref);
> > +
> > +    ds_clear(match);
> > +    ds_put_format(match, "inport == \"%s\" && nd_na",
> > redirect_port);
> > +    ovn_lflow_add(lflows, op->peer->od,
> > S_SWITCH_IN_CHECK_PORT_SEC, 80,
> > +                  ds_cstr(match),
> > +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> > +                  op->peer->lflow_ref);
> > +
> > +    ds_clear(match);
> > +    ds_put_format(match, "inport == \"%s\" && nd_ra",
> > redirect_port);
> > +    ovn_lflow_add(lflows, op->peer->od,
> > S_SWITCH_IN_CHECK_PORT_SEC, 80,
> > +                  ds_cstr(match),
> > +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> > +                  op->peer->lflow_ref);
> > +}
> > +
> >  /* This function adds ARP resolve flows related to a LSP. */
> >  static void
> >  build_arp_resolve_flows_for_lsp(
> > @@ -16900,6 +17123,8 @@
> > build_lswitch_and_lrouter_iterate_by_lrp(struct ovn_port *op,
> >                                  op->lflow_ref);
> >      build_lrouter_icmp_packet_toobig_admin_flows(op, lsi->lflows,
> > &lsi->match,
> >                                                   &lsi->actions,
> > op->lflow_ref);
> > +    build_lrouter_routing_protocol_redirect(op, lsi->lflows,
> > +                                            &lsi->match, &lsi-
> > >actions);
> >  }
> > 
> >  static void *
> > diff --git a/northd/northd.h b/northd/northd.h
> > index e04ec5856..9e326b746 100644
> > --- a/northd/northd.h
> > +++ b/northd/northd.h
> > @@ -93,6 +93,13 @@ ovn_datapath_find_by_key(struct hmap *datapaths,
> > uint32_t dp_key);
> > 
> >  bool od_has_lb_vip(const struct ovn_datapath *od);
> > 
> > +/* List of routing and routing-related protocols which
> > + * OVN is capable of redirecting from LRP to specific LSP. */
> > +enum redirected_routing_protcol_flag_type {
> > +    REDIRECT_BGP = (1 << 0),
> > +    REDIRECT_BFD = (1 << 1),
> > +};
> > +
> >  struct tracked_ovn_ports {
> >      /* tracked created ports.
> >       * hmapx node data is 'struct ovn_port *' */
> > diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> > index 3abd5f75b..ede38882a 100644
> > --- a/northd/ovn-northd.8.xml
> > +++ b/northd/ovn-northd.8.xml
> > @@ -284,6 +284,32 @@
> >          dropped in the next stage.
> >        </li>
> > 
> > +      <li>
> > +        <p>
> > +          For each logical port that's defined as a target of
> > routing protocol
> > +          redirecting (via <code>routing-protocol-redirect</code>
> > option set on
> > +          Logical Router Port), a filter is set in place that
> > disallows
> > +          following traffic exiting this port:
> > +        </p>
> > +        <ul>
> > +          <li>
> > +            ARP replies
> > +          </li>
> > +          <li>
> > +            IPv6 Neighbor Discovery - Router Advertisements
> > +          </li>
> > +          <li>
> > +            IPv6 Neighbor Discovery - Neighbor Advertisements
> > +          </li>
> > +        </ul>
> > +        <p>
> > +          Since this port shares IP and MAC addresses with the
> > Logical Router
> > +          Port, we wan't to prevent duplicate replies and
> > advertisements. This
> > +          is achieved by a rule with priority 80 that sets
> > +          <code>REGBIT_PORT_SEC_DROP" = 1; next;"</code>.
> > +        </p>
> > +      </li>
> > +
> >        <li>
> >          For each (enabled) vtep logical port, a priority 70 flow
> > is added which
> >          matches on all packets and applies the action
> > @@ -2002,6 +2028,34 @@ output;
> >          on the logical switch.
> >        </li>
> > 
> > +      <li>
> > +        <p>
> > +          For any logical port that's defined as a target of
> > routing protocol
> > +          redirecting (via <code>routing-protocol-redirect</code>
> > option set on
> > +          Logical Router Port), we redirect the traffic related to
> > protocols
> > +          specified in <code>routing-protocols</code> option. It's
> > acoomplished
> > +          with following priority-100 flows:
> > +        </p>
> > +        <ul>
> > +          <li>
> > +            Flows that match Logical Router Port's IPs and
> > destination port of
> > +            the routing daemon are redirected to this port to
> > allow external
> > +            peers' connection to the daemon listening on this
> > port.
> > +          </li>
> > +          <li>
> > +            Flows that match Logical Router Port's IPs and source
> > port of
> > +            the routing daemon are redirected to this port to
> > allow replies
> > +            from the peers.
> > +          </li>
> > +        </ul>
> > +        <p>
> > +          In addition to this, we add priority-100 rules that
> > +          <code>clone</code> ARP replies and IPv6 Neighbor
> > Advertisements to
> > +          this port as well. These allow to build proper ARP/IPv6
> > neighbor
> > +          list on this port.
> > +        </p>
> > +      </li>
> > +
> >        <li>
> >          Priority-90 flows for transit switches that forward
> > registered
> >          IP multicast traffic to their corresponding multicast
> > group , which
> > diff --git a/ovn-nb.xml b/ovn-nb.xml
> > index bbda423a5..2836f58f5 100644
> > --- a/ovn-nb.xml
> > +++ b/ovn-nb.xml
> > @@ -3575,6 +3575,48 @@ or
> >          </p>
> >        </column>
> > 
> > +      <column name="options" key="routing-protocol-redirect"
> > +              type='{"type": "string"}'>
> > +        <p>
> > +          NOTE: this feature is experimental and may be subject to
> > +          removal/change in the future.
> > +        </p>
> > +        <p>
> > +          This option expects a name of a Logical Switch Port
> > that's present
> > +          in the peer's Logical Switch. If set, it causes any
> > traffic
> > +          that's destined for Logical Router Port's IP addresses
> > (including
> > +          its IPv6 LLA) and the ports associated with routing
> > protocols defined
> > +          ip <code>routing-protocols</code> option, to be
> > redirected
> > +          to the specified Logical Switch Port.
> > +
> > +          This allows external routing daemons to be bound to a
> > port in OVN's
> > +          Logical Switch and act as if they were listening on
> > Logical Router
> > +          Port's IP addresses.
> > +        </p>
> > +      </column>
> > +
> > +      <column name="options" key="routing-protocols"
> > type='{"type": "string"}'>
> > +        <p>
> > +          NOTE: this feature is experimental and may be subject to
> > +          removal/change in the future.
> > +        </p>
> > +        <p>
> > +          This option expects a comma-separated list of routing,
> > and
> > +          routing-related protocols, whose control plane traffic
> > will be
> > +          redirected to a port specified in
> > +          <code>routing-protocol-redirect</code> option. Currently
> > supported
> > +          options are:
> > +        </p>
> > +        <ul>
> > +          <li>
> > +            <code>BGP</code> (forwards TCP port 179)
> > +          </li>
> > +          <li>
> > +            <code>BFD</code> (forwards UDP port 3784)
> > +          </li>
> > +        </ul>
> > +      </column>
> > +
> >        <column name="options" key="gateway_mtu_bypass">
> >          <p>
> >            When configured, represents a match expression, in the
> > same
> > diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> > index f2f42275a..bd05da3cd 100644
> > --- a/tests/ovn-northd.at
> > +++ b/tests/ovn-northd.at
> > @@ -13757,3 +13757,96 @@ AT_CHECK([grep -e "172.168.0.110" -e
> > "172.168.0.120" -e "10.0.0.3" -e "20.0.0.3"
> > 
> >  AT_CLEANUP
> >  ])
> > +
> > +OVN_FOR_EACH_NORTHD_NO_HV([
> > +AT_SETUP([Routing protocol control plane redirect])
> > +ovn_start
> > +
> > +check ovn-sbctl chassis-add hv1 geneve 127.0.0.1
> > +
> > +check ovn-nbctl lr-add lr -- \
> > +    lrp-add lr lr-ls 02:ac:10:01:00:01 172.16.1.1/24
> > +check ovn-nbctl --wait=sb set logical_router lr
> > options:chassis=hv1
> > +
> > +check ovn-nbctl ls-add ls -- \
> > +    lsp-add ls ls-lr -- \
> > +    lsp-set-type ls-lr router -- \
> > +    lsp-set-addresses ls-lr router -- \
> > +    lsp-set-options ls-lr router-port=lr-ls
> > +
> > +check ovn-nbctl lsp-add ls lsp-bgp -- \
> > +    lsp-set-addresses lsp-bgp unknown
> > +
> > +# Function that ensures that no redirect rules are installed.
> > +check_no_redirect() {
> > +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep
> > -E "tcp.dst == 179|tcp.src == 179" | wc -l], [0], [0
> > +])
> > +
> > +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec
> > | grep -E "priority=80" | wc -l], [0], [0
> > +])
> > +    check_no_bfd_redirect
> > +}
> > +
> > +# Function that ensures that no BFD redirect rules are installed.
> > +check_no_bfd_redirect() {
> > +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep
> > -E "udp.dst == 3784|udp.src == 3784" | wc -l], [0], [0
> > +])
> > +}
> > +
> > +# By default, no rules related to routing protocol redirect are
> > present
> > +check_no_redirect
> > +
> > +# Set "lsp-bgp" port as target of BGP control plane redirected
> > traffic
> > +check ovn-nbctl --wait=sb set logical_router_port lr-ls
> > options:routing-protocol-redirect=lsp-bgp
> > +check ovn-nbctl --wait=sb set logical_router_port lr-ls
> > options:routing-protocols=BGP
> > +
> > +# Check that BGP control plane traffic is redirected "lsp-bgp"
> > +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E
> > "tcp.dst == 179|tcp.src == 179" | ovn_strip_lflows], [0], [dnl
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst ==
> > 172.16.1.1 && tcp.dst == 179), action=(outport = "lsp-bgp";
> > output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst ==
> > 172.16.1.1 && tcp.src == 179), action=(outport = "lsp-bgp";
> > output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst ==
> > fe80::ac:10ff:fe01:1 && tcp.dst == 179), action=(outport = "lsp-
> > bgp"; output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst ==
> > fe80::ac:10ff:fe01:1 && tcp.src == 179), action=(outport = "lsp-
> > bgp"; output;)
> > +])
> > +
> > +# Check that ARP/ND traffic is cloned to the "lsp-bgp"
> > +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep
> > "arp.op == 2 && arp.tpa == 172.16.1.1" | ovn_strip_lflows], [0],
> > [dnl
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(arp.op ==
> > 2 && arp.tpa == 172.16.1.1), action=(clone { outport = "lsp-bgp";
> > output; }; outport = "ls-lr"; output;)
> > +])
> > +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "&&
> > nd_na" | ovn_strip_lflows], [0], [dnl
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst ==
> > fe80::ac:10ff:fe01:1 && nd_na), action=(clone { outport = "lsp-
> > bgp"; output; }; outport = "ls-lr"; output;)
> > +])
> > +
> > +# Check that at this point no BFD redirecting is present
> > +check_no_bfd_redirect
> > +
> > +# Add BFD traffic redirect
> > +check ovn-nbctl --wait=sb set logical_router_port lr-ls
> > options:routing-protocols=BGP,BFD
> > +
> > +# Check that BFD traffic is redirected to "lsp-bgp"
> > +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E
> > "udp.dst == 3784|udp.src == 3784" | ovn_strip_lflows], [0], [dnl
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst ==
> > 172.16.1.1 && udp.dst == 3784), action=(outport = "lsp-bgp";
> > output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst ==
> > 172.16.1.1 && udp.src == 3784), action=(outport = "lsp-bgp";
> > output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst ==
> > fe80::ac:10ff:fe01:1 && udp.dst == 3784), action=(outport = "lsp-
> > bgp"; output;)
> > +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst ==
> > fe80::ac:10ff:fe01:1 && udp.src == 3784), action=(outport = "lsp-
> > bgp"; output;)
> > +])
> > +
> > +
> > +# Check that ARP replies and ND advertisements are blocked from
> > exiting "lsp-bgp"
> > +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec |
> > grep "priority=80" | ovn_strip_lflows], [0], [dnl
> > +  table=??(ls_in_check_port_sec), priority=80   , match=(inport ==
> > "lsp-bgp" && arp.op == 2), action=(reg0[[15]] = 1; next;)
> > +  table=??(ls_in_check_port_sec), priority=80   , match=(inport ==
> > "lsp-bgp" && nd_na), action=(reg0[[15]] = 1; next;)
> > +  table=??(ls_in_check_port_sec), priority=80   , match=(inport ==
> > "lsp-bgp" && nd_ra), action=(reg0[[15]] = 1; next;)
> > +])
> > +
> > +# Remove 'bgp-redirect' option from LRP and check that rules are
> > removed
> > +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options
> > routing-protocol-redirect
> > +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options
> > routing-protocols
> > +check_no_redirect
> > +
> > +# Set non-existent LSP as target of 'bgp-redirect' and check that
> > no rules are added
> > +check ovn-nbctl --wait=sb set logical_router_port lr-ls
> > options:routing-protocol-redirect=lsp-foo
> > +check ovn-nbctl --wait=sb set logical_router_port lr-ls
> > options:routing-protocols=BGP,BFD
> > +check_no_redirect
> > +
> > +AT_CLEANUP
> > +])
> > diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> > index 7ba2e150b..c0adb8cc2 100644
> > --- a/tests/system-ovn.at
> > +++ b/tests/system-ovn.at
> > @@ -13504,3 +13504,123 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/failed to
> > query port patch-.*/d
> > 
> >  AT_CLEANUP
> >  ])
> > +
> > +OVN_FOR_EACH_NORTHD([
> > +AT_SETUP([Routing protocol redirect])
> > +AT_SKIP_IF([test $HAVE_NC = no])
> > +
> > +ovn_start
> > +OVS_TRAFFIC_VSWITCHD_START()
> > +
> > +ADD_BR([br-int])
> > +ADD_BR([br-ext])
> > +
> > +check ovs-ofctl add-flow br-ext action=normal
> > +# Set external-ids in br-int needed for ovn-controller
> > +check ovs-vsctl \
> > +        -- set Open_vSwitch . external-ids:system-id=hv1 \
> > +        -- set Open_vSwitch . external-ids:ovn-
> > remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
> > +        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
> > +        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1
> > \
> > +        -- set bridge br-int fail-mode=secure other-
> > config:disable-in-band=true
> > +
> > +# Start ovn-controller
> > +start_daemon ovn-controller
> > +
> > +check ovn-nbctl lr-add R1 \
> > +    -- set Logical_Router R1 options:chassis=hv1
> > +
> > +check ovn-nbctl ls-add public
> > +check ovn-nbctl ls-add bar
> > +
> > +check ovn-nbctl lrp-add R1 rp-public 00:00:02:01:02:03
> > 172.16.1.1/24
> > +check ovn-nbctl lrp-add R1 rp-bar 00:00:ff:00:00:01
> > 192.168.10.1/24
> > +
> > +check ovn-nbctl lsp-add public public-rp -- set
> > Logical_Switch_Port public-rp \
> > +    type=router options:router-port=rp-public \
> > +    -- lsp-set-addresses public-rp router
> > +
> > +check ovn-nbctl lsp-add bar bar-rp -- set Logical_Switch_Port bar-
> > rp \
> > +    type=router options:router-port=rp-bar \
> > +    -- lsp-set-addresses bar-rp router
> > +
> > +check ovn-nbctl lsp-add public bgp-daemon \
> > +    -- lsp-set-addresses bgp-daemon unknown
> > +
> > +# Setup container "bar1" representing host on an internal network
> > +ADD_NAMESPACES(bar1)
> > +ADD_VETH(bar1, bar1, br-int, "192.168.10.2/24",
> > "00:00:ff:ff:ff:01", \
> > +         "192.168.10.1")
> > +check ovn-nbctl lsp-add bar bar1 \
> > +    -- lsp-set-addresses bar1 "00:00:ff:ff:ff:01 192.168.10.2"
> > +
> > +# Setup SNAT for the internal host
> > +AT_CHECK([ovn-nbctl lr-nat-add R1 snat 172.16.1.1 192.168.10.2])
> > +
> > +# Configure external connectivity
> > +AT_CHECK([ovs-vsctl set Open_vSwitch . external-ids:ovn-bridge-
> > mappings=phynet:br-ext])
> > +check ovn-nbctl lsp-add public public1 \
> > +        -- lsp-set-addresses public1 unknown \
> > +        -- lsp-set-type public1 localnet \
> > +        -- lsp-set-options public1 network_name=phynet
> > +
> > +check ovn-nbctl --wait=hv sync
> > +
> > +# Set option that redirects BGP traffic to a LSP "bgp-daemon"
> > +check ovn-nbctl --wait=sb set logical_router_port rp-public
> > options:routing-protocol-redirect=bgp-daemon
> > +check ovn-nbctl --wait=sb set logical_router_port rp-public
> > options:routing-protocols=BGP
> > +
> > +# Create "bgp-daemon" interface in a namespace with IP and MAC
> > matching LRP "rp-public"
> > +ADD_NAMESPACES(bgp-daemon)
> > +ADD_VETH(bgp-daemon, bgp-daemon, br-int, "172.16.1.1/24",
> > "00:00:02:01:02:03")
> > +
> > +ADD_NAMESPACES(ext-foo)
> > +ADD_VETH(ext-foo, ext-foo, br-ext, "172.16.1.100/24",
> > "00:10:10:01:02:13", \
> > +         "172.16.1.1")
> > +
> > +# Flip the interface down/up to get proper IPv6 LLA
> > +NS_EXEC([bgp-daemon], [ip link set down bgp-daemon])
> > +NS_EXEC([bgp-daemon], [ip link set up bgp-daemon])
> > +NS_EXEC([ext-foo], [ip link set down ext-foo])
> > +NS_EXEC([ext-foo], [ip link set up ext-foo])
> > +
> > +# Wait until IPv6 LLA loses the "tentative" flag otherwise it
> > can't be bound to.
> > +OVS_WAIT_UNTIL([NS_EXEC([bgp-daemon], [ip a show dev bgp-daemon |
> > grep "fe80::" | grep -v tentative])])
> > +OVS_WAIT_UNTIL([NS_EXEC([ext-foo], [ip a show dev ext-foo | grep
> > "fe80::" | grep -v tentative])])
> > +
> > +# Verify that BGP control plane traffic is delivered to the "bgp-
> > daemon"
> > +# interface on both IPv4 and IPv6 LLA addresses
> > +NETNS_DAEMONIZE([bgp-daemon], [nc -l -k 172.16.1.1 179],
> > [bgp_v4.pid])
> > +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only
> > 172.16.1.1 179])
> > +
> > +NETNS_DAEMONIZE([bgp-daemon], [nc -l -6 -k
> > fe80::200:2ff:fe01:203%bgp-daemon 179], [bgp_v6.pid])
> > +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only -6
> > fe80::200:2ff:fe01:203%ext-foo 179])
> > +
> > +# Verify connection in other direction. i.e when daemon running on
> > "bgp-daemon" port
> > +# makes a client connection to its peer
> > +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 179],
> > [reply_bgp_v4.pid])
> > +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only
> > 172.16.1.100 179])
> > +
> > +NETNS_DAEMONIZE([ext-foo], [nc -l -6 -k
> > fe80::210:10ff:fe01:213%ext-foo 179], [reply_bgp_v6.pid])
> > +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only -6
> > fe80::210:10ff:fe01:213%bgp-daemon 179])
> > +
> > +# Verify that hosts on the internal network can reach external
> > networks
> > +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 2222],
> > [nc_external.pid])
> > +NS_CHECK_EXEC([bar1], [echo "TCP test" | nc -w 1 --send-only
> > 172.16.1.100 2222])
> > +
> > +OVS_APP_EXIT_AND_WAIT([ovn-controller])
> > +
> > +as ovn-sb
> > +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> > +
> > +as ovn-nb
> > +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> > +
> > +as northd
> > +OVS_APP_EXIT_AND_WAIT([ovn-northd])
> > +
> > +as
> > +OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
> > +/.*terminating with signal 15.*/d"])
> > +AT_CLEANUP
> > +])
> > --
> > 2.43.0
> > 
> > _______________________________________________
> > dev mailing list
> > dev@openvswitch.org
> > https://mail.openvswitch.org/mailman/listinfo/ovs-dev
> >

Martin et al.,

I plan to commit the branch patches and to create the 24.09 branch 
shortly. Since we stated intent to get this patch into 24.09, we will 
work to get it into main and branch-24.09 as soon as we can next week.

Thanks,
Mark Michelson

On 8/9/24 14:40, Martin Kalcok wrote:
> This change adds two new LRP options:
>   * routing-protocol-redirect
>   * routing-protocols
> 
> These allow redirection of a routing protocol traffic to
> an Logical Switch Port. This enables external routing daemons
> to listen on an interface bound to an LSP and effectively act
> as if they were listening on (and speaking from) LRP's IP address.
> 
> Option 'routing-protocols' takes a comma-separated list of routing
> protocols whose traffic should be redirected. Currently supported
> are BGP (tcp 179) and BFD (udp 3784).
> 
> Option 'routing-protocol-redirect' expects a string with an LSP
> name.
> 
> When both of these options are set, any traffic entering LS
> that's destined for LRP's IP addresses (including IPv6 LLA) and
> routing protocol's port number, is redirected to the LSP specified
> in the 'routing-protocol-redirect' value.
> 
> NOTE: this feature is experimental and may be subject to
> removal/change in the future.
> 
> Signed-off-by: Martin Kalcok <martin.kalcok@canonical.com>
> ---
>   
>   I'm posting this v7 patch just as a preview. northd occasionally
>   crashes in the added datapath tests. It's an issue I can't seem to
>   reproduce in my test deployment, only during the tests. Until that's
>   resolved, this patch is not suitable for merging.
> 
>   Compared to v6, this patch includes:
>   Fix for cloning of ARP/ND messages. Now the messages are
>   properly delivered to both, redirect port and the LRP.
> 
>   It also adds functional test that verifies ability of hosts on
>   internal networks to communicate with the external networks
>   uninterupted, even when the worwarding is enabled
> 
> 
>   northd/northd.c         | 225 ++++++++++++++++++++++++++++++++++++++++
>   northd/northd.h         |   7 ++
>   northd/ovn-northd.8.xml |  54 ++++++++++
>   ovn-nb.xml              |  42 ++++++++
>   tests/ovn-northd.at     |  93 +++++++++++++++++
>   tests/system-ovn.at     | 120 +++++++++++++++++++++
>   6 files changed, 541 insertions(+)
> 
> diff --git a/northd/northd.c b/northd/northd.c
> index 0c73e70df..9f2fd5278 100644
> --- a/northd/northd.c
> +++ b/northd/northd.c
> @@ -13935,6 +13935,229 @@ build_arp_resolve_flows_for_lrp(struct ovn_port *op,
>       }
>   }
>   
> +static void
> +build_routing_protocols_redirect_rule__(
> +        const char *s_addr, const char *redirect_port_name, int protocol_port,
> +        const char *proto, bool is_ipv6, struct ovn_port *ls_peer,
> +        struct lflow_table *lflows, struct ds *match, struct ds *actions)
> +{
> +    int ip_ver = is_ipv6 ? 6 : 4;
> +    ds_clear(actions);
> +    ds_put_format(actions, "outport = \"%s\"; output;", redirect_port_name);
> +
> +    /* Redirect packets in the input pipeline destined for LR's IP
> +     * and the routing protocol's port to the LSP specified in
> +     * 'routing-protocol-redirect' option.*/
> +    ds_clear(match);
> +    ds_put_format(match, "ip%d.dst == %s && %s.dst == %d", ip_ver, s_addr,
> +                  proto, protocol_port);
> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                  ds_cstr(match),
> +                  ds_cstr(actions),
> +                  ls_peer->lflow_ref);
> +
> +    /* To accomodate "peer" nature of the routing daemons, redirect also
> +     * replies to the daemons' client requests. */
> +    ds_clear(match);
> +    ds_put_format(match, "ip%d.dst == %s && %s.src == %d", ip_ver, s_addr,
> +                  proto, protocol_port);
> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                  ds_cstr(match),
> +                  ds_cstr(actions),
> +                  ls_peer->lflow_ref);
> +}
> +
> +static void
> +apply_routing_protocols_redirect__(
> +        const char *s_addr, const char *redirect_port_name, int protocol_flags,
> +        bool is_ipv6, struct ovn_port *ls_peer, struct lflow_table *lflows,
> +        struct ds *match, struct ds *actions)
> +{
> +    if (protocol_flags & REDIRECT_BGP) {
> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
> +                                                179, "tcp", is_ipv6, ls_peer,
> +                                                lflows, match, actions);
> +    }
> +
> +    if (protocol_flags & REDIRECT_BFD) {
> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
> +                                                3784, "udp", is_ipv6, ls_peer,
> +                                                lflows, match, actions);
> +    }
> +
> +    /* Because the redirected port shares IP and MAC addresses with the LRP,
> +     * special consideration needs to be given to the signaling protocols. */
> +    if (is_ipv6) {
> +        /* Ensure that redirect port receives copy of NA messages destined to
> +         * its IP.*/
> +        ds_clear(match);
> +        ds_clear(actions);
> +        ds_put_format(actions,
> +                     "clone { outport = \"%s\"; output; }; "
> +                     "outport = %s; output;",
> +                      redirect_port_name, ls_peer->json_key);
> +        ds_put_format(match, "ip6.dst == %s && nd_na", s_addr);
> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                      ds_cstr(match),
> +                      ds_cstr(actions),
> +                      ls_peer->lflow_ref);
> +    } else {
> +        /* Ensure that redirect port receives copy of ARP replies destined to
> +         * its IP */
> +        ds_clear(match);
> +        ds_clear(actions);
> +        ds_put_format(actions,
> +                      "clone { outport = \"%s\"; output; }; "
> +                      "outport = %s; output;",
> +                      redirect_port_name, ls_peer->json_key);
> +        ds_put_format(match, "arp.op == 2 && arp.tpa == %s", s_addr);
> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
> +                      ds_cstr(match),
> +                      ds_cstr(actions),
> +                      ls_peer->lflow_ref);
> +    }
> +}
> +
> +static int
> +parse_redirected_routing_protocols(struct ovn_port *lrp) {
> +    int redirected_protocol_flags = 0;
> +    const char *redirect_protocols = smap_get(&lrp->nbrp->options,
> +                                              "routing-protocols");
> +    if (redirect_protocols == NULL) {
> +        return redirected_protocol_flags;
> +    }
> +
> +    char *proto;
> +    char *save_ptr = NULL;
> +    char *tokstr = xstrdup(redirect_protocols);
> +    for (proto = strtok_r(tokstr, ",", &save_ptr); proto != NULL;
> +         proto = strtok_r(NULL, ",", &save_ptr)) {
> +        if (!strcmp(proto, "BGP")) {
> +            redirected_protocol_flags |= REDIRECT_BGP;
> +            continue;
> +        }
> +
> +        if (!strcmp(proto, "BFD")) {
> +            redirected_protocol_flags |= REDIRECT_BFD;
> +            continue;
> +        }
> +
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocols' encountered unknown "
> +                          "value %s",
> +                          proto);
> +    }
> +    free(tokstr);
> +    return redirected_protocol_flags;
> +}
> +
> +static void
> +build_lrouter_routing_protocol_redirect(
> +        struct ovn_port *op, struct lflow_table *lflows,
> +        struct ds *match, struct ds *actions)
> +{
> +    /* LRP has to have a peer.*/
> +    if (op->peer == NULL) {
> +        return;
> +    }
> +
> +    /* LRP has to have NB record.*/
> +    if (op->nbrp == NULL) {
> +        return;
> +    }
> +
> +    /* Proceed only for LRPs that have 'routing-protocol-redirect' option set.
> +     * Value of this option is the name of LSP to which the routing protocol
> +     * traffic will be redirected. */
> +    const char *redirect_port = smap_get(&op->nbrp->options,
> +                                         "routing-protocol-redirect");
> +    if (redirect_port == NULL) {
> +        return;
> +    }
> +
> +    if (op->cr_port != NULL) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is not "
> +                          "supported on Distributed Gateway Port '%s'",
> +                          op->key);
> +        return;
> +    }
> +
> +    /* Ensure that LSP, to which the routing protocol traffic is redirected,
> +     * exists. */
> +    struct ovn_port *peer_lsp;
> +    bool redirect_port_exists = false;
> +    HMAP_FOR_EACH (peer_lsp, dp_node, &op->peer->od->ports) {
> +        size_t peer_lsp_s = strlen(peer_lsp->key);
> +        if (peer_lsp_s == strlen(redirect_port)
> +            && !strncmp(peer_lsp->key, redirect_port, peer_lsp_s)){
> +            redirect_port_exists = true;
> +            break;
> +        }
> +    }
> +
> +    if (!redirect_port_exists) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' set on Logical "
> +                          "Router Port '%s' refers to non-existent Logical "
> +                          "Switch Port. Routing protocol redirecting won't be "
> +                          "configured.",
> +                          op->key);
> +        return;
> +    }
> +
> +    int redirected_protocols = parse_redirected_routing_protocols(op);
> +    if (!redirected_protocols) {
> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is set on "
> +                          "Logical Router Port '%s' but no known protocols "
> +                          "were set via 'routing-protocols' options. This "
> +                          "configuration has no effect.",
> +                          op->key);
> +        return;
> +    }
> +
> +    /* Redirected traffic destined for LRP's IPs and the specified routing
> +     * protocol ports to the port defined in 'routing-protocol-redirect'
> +     * option.*/
> +    for (size_t i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
> +        const char *ip_s = op->lrp_networks.ipv4_addrs[i].addr_s;
> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> +                                           redirected_protocols, false,
> +                                           op->peer, lflows,match, actions);
> +    }
> +    for (size_t i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
> +        const char *ip_s = op->lrp_networks.ipv6_addrs[i].addr_s;
> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
> +                                           redirected_protocols, true,
> +                                           op->peer, lflows,match, actions);
> +    }
> +
> +    /* Drop ARP replies and IPv6 RA/NA packets originating from
> +     * 'routing-protocol-redirect' LSP. As this port shares IP and MAC
> +     * addresses with LRP, we don't want to create duplicates.*/
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && arp.op == 2", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && nd_na", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +
> +    ds_clear(match);
> +    ds_put_format(match, "inport == \"%s\" && nd_ra", redirect_port);
> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
> +                  ds_cstr(match),
> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
> +                  op->peer->lflow_ref);
> +}
> +
>   /* This function adds ARP resolve flows related to a LSP. */
>   static void
>   build_arp_resolve_flows_for_lsp(
> @@ -16900,6 +17123,8 @@ build_lswitch_and_lrouter_iterate_by_lrp(struct ovn_port *op,
>                                   op->lflow_ref);
>       build_lrouter_icmp_packet_toobig_admin_flows(op, lsi->lflows, &lsi->match,
>                                                    &lsi->actions, op->lflow_ref);
> +    build_lrouter_routing_protocol_redirect(op, lsi->lflows,
> +                                            &lsi->match, &lsi->actions);
>   }
>   
>   static void *
> diff --git a/northd/northd.h b/northd/northd.h
> index e04ec5856..9e326b746 100644
> --- a/northd/northd.h
> +++ b/northd/northd.h
> @@ -93,6 +93,13 @@ ovn_datapath_find_by_key(struct hmap *datapaths, uint32_t dp_key);
>   
>   bool od_has_lb_vip(const struct ovn_datapath *od);
>   
> +/* List of routing and routing-related protocols which
> + * OVN is capable of redirecting from LRP to specific LSP. */
> +enum redirected_routing_protcol_flag_type {
> +    REDIRECT_BGP = (1 << 0),
> +    REDIRECT_BFD = (1 << 1),
> +};
> +
>   struct tracked_ovn_ports {
>       /* tracked created ports.
>        * hmapx node data is 'struct ovn_port *' */
> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> index 3abd5f75b..ede38882a 100644
> --- a/northd/ovn-northd.8.xml
> +++ b/northd/ovn-northd.8.xml
> @@ -284,6 +284,32 @@
>           dropped in the next stage.
>         </li>
>   
> +      <li>
> +        <p>
> +          For each logical port that's defined as a target of routing protocol
> +          redirecting (via <code>routing-protocol-redirect</code> option set on
> +          Logical Router Port), a filter is set in place that disallows
> +          following traffic exiting this port:
> +        </p>
> +        <ul>
> +          <li>
> +            ARP replies
> +          </li>
> +          <li>
> +            IPv6 Neighbor Discovery - Router Advertisements
> +          </li>
> +          <li>
> +            IPv6 Neighbor Discovery - Neighbor Advertisements
> +          </li>
> +        </ul>
> +        <p>
> +          Since this port shares IP and MAC addresses with the Logical Router
> +          Port, we wan't to prevent duplicate replies and advertisements. This
> +          is achieved by a rule with priority 80 that sets
> +          <code>REGBIT_PORT_SEC_DROP" = 1; next;"</code>.
> +        </p>
> +      </li>
> +
>         <li>
>           For each (enabled) vtep logical port, a priority 70 flow is added which
>           matches on all packets and applies the action
> @@ -2002,6 +2028,34 @@ output;
>           on the logical switch.
>         </li>
>   
> +      <li>
> +        <p>
> +          For any logical port that's defined as a target of routing protocol
> +          redirecting (via <code>routing-protocol-redirect</code> option set on
> +          Logical Router Port), we redirect the traffic related to protocols
> +          specified in <code>routing-protocols</code> option. It's acoomplished
> +          with following priority-100 flows:
> +        </p>
> +        <ul>
> +          <li>
> +            Flows that match Logical Router Port's IPs and destination port of
> +            the routing daemon are redirected to this port to allow external
> +            peers' connection to the daemon listening on this port.
> +          </li>
> +          <li>
> +            Flows that match Logical Router Port's IPs and source port of
> +            the routing daemon are redirected to this port to allow replies
> +            from the peers.
> +          </li>
> +        </ul>
> +        <p>
> +          In addition to this, we add priority-100 rules that
> +          <code>clone</code> ARP replies and IPv6 Neighbor Advertisements to
> +          this port as well. These allow to build proper ARP/IPv6 neighbor
> +          list on this port.
> +        </p>
> +      </li>
> +
>         <li>
>           Priority-90 flows for transit switches that forward registered
>           IP multicast traffic to their corresponding multicast group , which
> diff --git a/ovn-nb.xml b/ovn-nb.xml
> index bbda423a5..2836f58f5 100644
> --- a/ovn-nb.xml
> +++ b/ovn-nb.xml
> @@ -3575,6 +3575,48 @@ or
>           </p>
>         </column>
>   
> +      <column name="options" key="routing-protocol-redirect"
> +              type='{"type": "string"}'>
> +        <p>
> +          NOTE: this feature is experimental and may be subject to
> +          removal/change in the future.
> +        </p>
> +        <p>
> +          This option expects a name of a Logical Switch Port that's present
> +          in the peer's Logical Switch. If set, it causes any traffic
> +          that's destined for Logical Router Port's IP addresses (including
> +          its IPv6 LLA) and the ports associated with routing protocols defined
> +          ip <code>routing-protocols</code> option, to be redirected
> +          to the specified Logical Switch Port.
> +
> +          This allows external routing daemons to be bound to a port in OVN's
> +          Logical Switch and act as if they were listening on Logical Router
> +          Port's IP addresses.
> +        </p>
> +      </column>
> +
> +      <column name="options" key="routing-protocols" type='{"type": "string"}'>
> +        <p>
> +          NOTE: this feature is experimental and may be subject to
> +          removal/change in the future.
> +        </p>
> +        <p>
> +          This option expects a comma-separated list of routing, and
> +          routing-related protocols, whose control plane traffic will be
> +          redirected to a port specified in
> +          <code>routing-protocol-redirect</code> option. Currently supported
> +          options are:
> +        </p>
> +        <ul>
> +          <li>
> +            <code>BGP</code> (forwards TCP port 179)
> +          </li>
> +          <li>
> +            <code>BFD</code> (forwards UDP port 3784)
> +          </li>
> +        </ul>
> +      </column>
> +
>         <column name="options" key="gateway_mtu_bypass">
>           <p>
>             When configured, represents a match expression, in the same
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index f2f42275a..bd05da3cd 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -13757,3 +13757,96 @@ AT_CHECK([grep -e "172.168.0.110" -e "172.168.0.120" -e "10.0.0.3" -e "20.0.0.3"
>   
>   AT_CLEANUP
>   ])
> +
> +OVN_FOR_EACH_NORTHD_NO_HV([
> +AT_SETUP([Routing protocol control plane redirect])
> +ovn_start
> +
> +check ovn-sbctl chassis-add hv1 geneve 127.0.0.1
> +
> +check ovn-nbctl lr-add lr -- \
> +    lrp-add lr lr-ls 02:ac:10:01:00:01 172.16.1.1/24
> +check ovn-nbctl --wait=sb set logical_router lr options:chassis=hv1
> +
> +check ovn-nbctl ls-add ls -- \
> +    lsp-add ls ls-lr -- \
> +    lsp-set-type ls-lr router -- \
> +    lsp-set-addresses ls-lr router -- \
> +    lsp-set-options ls-lr router-port=lr-ls
> +
> +check ovn-nbctl lsp-add ls lsp-bgp -- \
> +    lsp-set-addresses lsp-bgp unknown
> +
> +# Function that ensures that no redirect rules are installed.
> +check_no_redirect() {
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "tcp.dst == 179|tcp.src == 179" | wc -l], [0], [0
> +])
> +
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep -E "priority=80" | wc -l], [0], [0
> +])
> +    check_no_bfd_redirect
> +}
> +
> +# Function that ensures that no BFD redirect rules are installed.
> +check_no_bfd_redirect() {
> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "udp.dst == 3784|udp.src == 3784" | wc -l], [0], [0
> +])
> +}
> +
> +# By default, no rules related to routing protocol redirect are present
> +check_no_redirect
> +
> +# Set "lsp-bgp" port as target of BGP control plane redirected traffic
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-bgp
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP
> +
> +# Check that BGP control plane traffic is redirected "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "tcp.dst == 179|tcp.src == 179" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
> +])
> +
> +# Check that ARP/ND traffic is cloned to the "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "arp.op == 2 && arp.tpa == 172.16.1.1" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(arp.op == 2 && arp.tpa == 172.16.1.1), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
> +])
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "&& nd_na" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && nd_na), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
> +])
> +
> +# Check that at this point no BFD redirecting is present
> +check_no_bfd_redirect
> +
> +# Add BFD traffic redirect
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
> +
> +# Check that BFD traffic is redirected to "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "udp.dst == 3784|udp.src == 3784" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
> +])
> +
> +
> +# Check that ARP replies and ND advertisements are blocked from exiting "lsp-bgp"
> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep "priority=80" | ovn_strip_lflows], [0], [dnl
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && arp.op == 2), action=(reg0[[15]] = 1; next;)
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_na), action=(reg0[[15]] = 1; next;)
> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_ra), action=(reg0[[15]] = 1; next;)
> +])
> +
> +# Remove 'bgp-redirect' option from LRP and check that rules are removed
> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocol-redirect
> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocols
> +check_no_redirect
> +
> +# Set non-existent LSP as target of 'bgp-redirect' and check that no rules are added
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-foo
> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
> +check_no_redirect
> +
> +AT_CLEANUP
> +])
> diff --git a/tests/system-ovn.at b/tests/system-ovn.at
> index 7ba2e150b..c0adb8cc2 100644
> --- a/tests/system-ovn.at
> +++ b/tests/system-ovn.at
> @@ -13504,3 +13504,123 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/failed to query port patch-.*/d
>   
>   AT_CLEANUP
>   ])
> +
> +OVN_FOR_EACH_NORTHD([
> +AT_SETUP([Routing protocol redirect])
> +AT_SKIP_IF([test $HAVE_NC = no])
> +
> +ovn_start
> +OVS_TRAFFIC_VSWITCHD_START()
> +
> +ADD_BR([br-int])
> +ADD_BR([br-ext])
> +
> +check ovs-ofctl add-flow br-ext action=normal
> +# Set external-ids in br-int needed for ovn-controller
> +check ovs-vsctl \
> +        -- set Open_vSwitch . external-ids:system-id=hv1 \
> +        -- set Open_vSwitch . external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
> +        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
> +        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
> +        -- set bridge br-int fail-mode=secure other-config:disable-in-band=true
> +
> +# Start ovn-controller
> +start_daemon ovn-controller
> +
> +check ovn-nbctl lr-add R1 \
> +    -- set Logical_Router R1 options:chassis=hv1
> +
> +check ovn-nbctl ls-add public
> +check ovn-nbctl ls-add bar
> +
> +check ovn-nbctl lrp-add R1 rp-public 00:00:02:01:02:03 172.16.1.1/24
> +check ovn-nbctl lrp-add R1 rp-bar 00:00:ff:00:00:01 192.168.10.1/24
> +
> +check ovn-nbctl lsp-add public public-rp -- set Logical_Switch_Port public-rp \
> +    type=router options:router-port=rp-public \
> +    -- lsp-set-addresses public-rp router
> +
> +check ovn-nbctl lsp-add bar bar-rp -- set Logical_Switch_Port bar-rp \
> +    type=router options:router-port=rp-bar \
> +    -- lsp-set-addresses bar-rp router
> +
> +check ovn-nbctl lsp-add public bgp-daemon \
> +    -- lsp-set-addresses bgp-daemon unknown
> +
> +# Setup container "bar1" representing host on an internal network
> +ADD_NAMESPACES(bar1)
> +ADD_VETH(bar1, bar1, br-int, "192.168.10.2/24", "00:00:ff:ff:ff:01", \
> +         "192.168.10.1")
> +check ovn-nbctl lsp-add bar bar1 \
> +    -- lsp-set-addresses bar1 "00:00:ff:ff:ff:01 192.168.10.2"
> +
> +# Setup SNAT for the internal host
> +AT_CHECK([ovn-nbctl lr-nat-add R1 snat 172.16.1.1 192.168.10.2])
> +
> +# Configure external connectivity
> +AT_CHECK([ovs-vsctl set Open_vSwitch . external-ids:ovn-bridge-mappings=phynet:br-ext])
> +check ovn-nbctl lsp-add public public1 \
> +        -- lsp-set-addresses public1 unknown \
> +        -- lsp-set-type public1 localnet \
> +        -- lsp-set-options public1 network_name=phynet
> +
> +check ovn-nbctl --wait=hv sync
> +
> +# Set option that redirects BGP traffic to a LSP "bgp-daemon"
> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocol-redirect=bgp-daemon
> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocols=BGP
> +
> +# Create "bgp-daemon" interface in a namespace with IP and MAC matching LRP "rp-public"
> +ADD_NAMESPACES(bgp-daemon)
> +ADD_VETH(bgp-daemon, bgp-daemon, br-int, "172.16.1.1/24", "00:00:02:01:02:03")
> +
> +ADD_NAMESPACES(ext-foo)
> +ADD_VETH(ext-foo, ext-foo, br-ext, "172.16.1.100/24", "00:10:10:01:02:13", \
> +         "172.16.1.1")
> +
> +# Flip the interface down/up to get proper IPv6 LLA
> +NS_EXEC([bgp-daemon], [ip link set down bgp-daemon])
> +NS_EXEC([bgp-daemon], [ip link set up bgp-daemon])
> +NS_EXEC([ext-foo], [ip link set down ext-foo])
> +NS_EXEC([ext-foo], [ip link set up ext-foo])
> +
> +# Wait until IPv6 LLA loses the "tentative" flag otherwise it can't be bound to.
> +OVS_WAIT_UNTIL([NS_EXEC([bgp-daemon], [ip a show dev bgp-daemon | grep "fe80::" | grep -v tentative])])
> +OVS_WAIT_UNTIL([NS_EXEC([ext-foo], [ip a show dev ext-foo | grep "fe80::" | grep -v tentative])])
> +
> +# Verify that BGP control plane traffic is delivered to the "bgp-daemon"
> +# interface on both IPv4 and IPv6 LLA addresses
> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -k 172.16.1.1 179], [bgp_v4.pid])
> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only 172.16.1.1 179])
> +
> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -6 -k fe80::200:2ff:fe01:203%bgp-daemon 179], [bgp_v6.pid])
> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only -6 fe80::200:2ff:fe01:203%ext-foo 179])
> +
> +# Verify connection in other direction. i.e when daemon running on "bgp-daemon" port
> +# makes a client connection to its peer
> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 179], [reply_bgp_v4.pid])
> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only 172.16.1.100 179])
> +
> +NETNS_DAEMONIZE([ext-foo], [nc -l -6 -k fe80::210:10ff:fe01:213%ext-foo 179], [reply_bgp_v6.pid])
> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only -6 fe80::210:10ff:fe01:213%bgp-daemon 179])
> +
> +# Verify that hosts on the internal network can reach external networks
> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 2222], [nc_external.pid])
> +NS_CHECK_EXEC([bar1], [echo "TCP test" | nc -w 1 --send-only 172.16.1.100 2222])
> +
> +OVS_APP_EXIT_AND_WAIT([ovn-controller])
> +
> +as ovn-sb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as ovn-nb
> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
> +
> +as northd
> +OVS_APP_EXIT_AND_WAIT([ovn-northd])
> +
> +as
> +OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
> +/.*terminating with signal 15.*/d"])
> +AT_CLEANUP
> +])

> On 10 Aug 2024, at 00:17, Mark Michelson <mmichels@redhat.com> wrote:
> 
> Martin et al.,
> 
> I plan to commit the branch patches and to create the 24.09 branch shortly. Since we stated intent to get this patch into 24.09, we will work to get it into main and branch-24.09 as soon as we can next week.
> 
Hi Mark. Thank you for leniency with regards to this patch. I’m putting all my efforts to fixing this.

Martin.
 
> Thanks,
> Mark Michelson
> 
> On 8/9/24 14:40, Martin Kalcok wrote:
>> This change adds two new LRP options:
>>  * routing-protocol-redirect
>>  * routing-protocols
>> These allow redirection of a routing protocol traffic to
>> an Logical Switch Port. This enables external routing daemons
>> to listen on an interface bound to an LSP and effectively act
>> as if they were listening on (and speaking from) LRP's IP address.
>> Option 'routing-protocols' takes a comma-separated list of routing
>> protocols whose traffic should be redirected. Currently supported
>> are BGP (tcp 179) and BFD (udp 3784).
>> Option 'routing-protocol-redirect' expects a string with an LSP
>> name.
>> When both of these options are set, any traffic entering LS
>> that's destined for LRP's IP addresses (including IPv6 LLA) and
>> routing protocol's port number, is redirected to the LSP specified
>> in the 'routing-protocol-redirect' value.
>> NOTE: this feature is experimental and may be subject to
>> removal/change in the future.
>> Signed-off-by: Martin Kalcok <martin.kalcok@canonical.com>
>> ---
>>    I'm posting this v7 patch just as a preview. northd occasionally
>>  crashes in the added datapath tests. It's an issue I can't seem to
>>  reproduce in my test deployment, only during the tests. Until that's
>>  resolved, this patch is not suitable for merging.
>>  Compared to v6, this patch includes:
>>  Fix for cloning of ARP/ND messages. Now the messages are
>>  properly delivered to both, redirect port and the LRP.
>>  It also adds functional test that verifies ability of hosts on
>>  internal networks to communicate with the external networks
>>  uninterupted, even when the worwarding is enabled
>>  northd/northd.c         | 225 ++++++++++++++++++++++++++++++++++++++++
>>  northd/northd.h         |   7 ++
>>  northd/ovn-northd.8.xml |  54 ++++++++++
>>  ovn-nb.xml              |  42 ++++++++
>>  tests/ovn-northd.at     |  93 +++++++++++++++++
>>  tests/system-ovn.at     | 120 +++++++++++++++++++++
>>  6 files changed, 541 insertions(+)
>> diff --git a/northd/northd.c b/northd/northd.c
>> index 0c73e70df..9f2fd5278 100644
>> --- a/northd/northd.c
>> +++ b/northd/northd.c
>> @@ -13935,6 +13935,229 @@ build_arp_resolve_flows_for_lrp(struct ovn_port *op,
>>      }
>>  }
>>  +static void
>> +build_routing_protocols_redirect_rule__(
>> +        const char *s_addr, const char *redirect_port_name, int protocol_port,
>> +        const char *proto, bool is_ipv6, struct ovn_port *ls_peer,
>> +        struct lflow_table *lflows, struct ds *match, struct ds *actions)
>> +{
>> +    int ip_ver = is_ipv6 ? 6 : 4;
>> +    ds_clear(actions);
>> +    ds_put_format(actions, "outport = \"%s\"; output;", redirect_port_name);
>> +
>> +    /* Redirect packets in the input pipeline destined for LR's IP
>> +     * and the routing protocol's port to the LSP specified in
>> +     * 'routing-protocol-redirect' option.*/
>> +    ds_clear(match);
>> +    ds_put_format(match, "ip%d.dst == %s && %s.dst == %d", ip_ver, s_addr,
>> +                  proto, protocol_port);
>> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
>> +                  ds_cstr(match),
>> +                  ds_cstr(actions),
>> +                  ls_peer->lflow_ref);
>> +
>> +    /* To accomodate "peer" nature of the routing daemons, redirect also
>> +     * replies to the daemons' client requests. */
>> +    ds_clear(match);
>> +    ds_put_format(match, "ip%d.dst == %s && %s.src == %d", ip_ver, s_addr,
>> +                  proto, protocol_port);
>> +    ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
>> +                  ds_cstr(match),
>> +                  ds_cstr(actions),
>> +                  ls_peer->lflow_ref);
>> +}
>> +
>> +static void
>> +apply_routing_protocols_redirect__(
>> +        const char *s_addr, const char *redirect_port_name, int protocol_flags,
>> +        bool is_ipv6, struct ovn_port *ls_peer, struct lflow_table *lflows,
>> +        struct ds *match, struct ds *actions)
>> +{
>> +    if (protocol_flags & REDIRECT_BGP) {
>> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
>> +                                                179, "tcp", is_ipv6, ls_peer,
>> +                                                lflows, match, actions);
>> +    }
>> +
>> +    if (protocol_flags & REDIRECT_BFD) {
>> +        build_routing_protocols_redirect_rule__(s_addr, redirect_port_name,
>> +                                                3784, "udp", is_ipv6, ls_peer,
>> +                                                lflows, match, actions);
>> +    }
>> +
>> +    /* Because the redirected port shares IP and MAC addresses with the LRP,
>> +     * special consideration needs to be given to the signaling protocols. */
>> +    if (is_ipv6) {
>> +        /* Ensure that redirect port receives copy of NA messages destined to
>> +         * its IP.*/
>> +        ds_clear(match);
>> +        ds_clear(actions);
>> +        ds_put_format(actions,
>> +                     "clone { outport = \"%s\"; output; }; "
>> +                     "outport = %s; output;",
>> +                      redirect_port_name, ls_peer->json_key);
>> +        ds_put_format(match, "ip6.dst == %s && nd_na", s_addr);
>> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
>> +                      ds_cstr(match),
>> +                      ds_cstr(actions),
>> +                      ls_peer->lflow_ref);
>> +    } else {
>> +        /* Ensure that redirect port receives copy of ARP replies destined to
>> +         * its IP */
>> +        ds_clear(match);
>> +        ds_clear(actions);
>> +        ds_put_format(actions,
>> +                      "clone { outport = \"%s\"; output; }; "
>> +                      "outport = %s; output;",
>> +                      redirect_port_name, ls_peer->json_key);
>> +        ds_put_format(match, "arp.op == 2 && arp.tpa == %s", s_addr);
>> +        ovn_lflow_add(lflows, ls_peer->od, S_SWITCH_IN_L2_LKUP, 100,
>> +                      ds_cstr(match),
>> +                      ds_cstr(actions),
>> +                      ls_peer->lflow_ref);
>> +    }
>> +}
>> +
>> +static int
>> +parse_redirected_routing_protocols(struct ovn_port *lrp) {
>> +    int redirected_protocol_flags = 0;
>> +    const char *redirect_protocols = smap_get(&lrp->nbrp->options,
>> +                                              "routing-protocols");
>> +    if (redirect_protocols == NULL) {
>> +        return redirected_protocol_flags;
>> +    }
>> +
>> +    char *proto;
>> +    char *save_ptr = NULL;
>> +    char *tokstr = xstrdup(redirect_protocols);
>> +    for (proto = strtok_r(tokstr, ",", &save_ptr); proto != NULL;
>> +         proto = strtok_r(NULL, ",", &save_ptr)) {
>> +        if (!strcmp(proto, "BGP")) {
>> +            redirected_protocol_flags |= REDIRECT_BGP;
>> +            continue;
>> +        }
>> +
>> +        if (!strcmp(proto, "BFD")) {
>> +            redirected_protocol_flags |= REDIRECT_BFD;
>> +            continue;
>> +        }
>> +
>> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
>> +        VLOG_WARN_RL(&rl, "Option 'routing-protocols' encountered unknown "
>> +                          "value %s",
>> +                          proto);
>> +    }
>> +    free(tokstr);
>> +    return redirected_protocol_flags;
>> +}
>> +
>> +static void
>> +build_lrouter_routing_protocol_redirect(
>> +        struct ovn_port *op, struct lflow_table *lflows,
>> +        struct ds *match, struct ds *actions)
>> +{
>> +    /* LRP has to have a peer.*/
>> +    if (op->peer == NULL) {
>> +        return;
>> +    }
>> +
>> +    /* LRP has to have NB record.*/
>> +    if (op->nbrp == NULL) {
>> +        return;
>> +    }
>> +
>> +    /* Proceed only for LRPs that have 'routing-protocol-redirect' option set.
>> +     * Value of this option is the name of LSP to which the routing protocol
>> +     * traffic will be redirected. */
>> +    const char *redirect_port = smap_get(&op->nbrp->options,
>> +                                         "routing-protocol-redirect");
>> +    if (redirect_port == NULL) {
>> +        return;
>> +    }
>> +
>> +    if (op->cr_port != NULL) {
>> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
>> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is not "
>> +                          "supported on Distributed Gateway Port '%s'",
>> +                          op->key);
>> +        return;
>> +    }
>> +
>> +    /* Ensure that LSP, to which the routing protocol traffic is redirected,
>> +     * exists. */
>> +    struct ovn_port *peer_lsp;
>> +    bool redirect_port_exists = false;
>> +    HMAP_FOR_EACH (peer_lsp, dp_node, &op->peer->od->ports) {
>> +        size_t peer_lsp_s = strlen(peer_lsp->key);
>> +        if (peer_lsp_s == strlen(redirect_port)
>> +            && !strncmp(peer_lsp->key, redirect_port, peer_lsp_s)){
>> +            redirect_port_exists = true;
>> +            break;
>> +        }
>> +    }
>> +
>> +    if (!redirect_port_exists) {
>> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
>> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' set on Logical "
>> +                          "Router Port '%s' refers to non-existent Logical "
>> +                          "Switch Port. Routing protocol redirecting won't be "
>> +                          "configured.",
>> +                          op->key);
>> +        return;
>> +    }
>> +
>> +    int redirected_protocols = parse_redirected_routing_protocols(op);
>> +    if (!redirected_protocols) {
>> +        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
>> +        VLOG_WARN_RL(&rl, "Option 'routing-protocol-redirect' is set on "
>> +                          "Logical Router Port '%s' but no known protocols "
>> +                          "were set via 'routing-protocols' options. This "
>> +                          "configuration has no effect.",
>> +                          op->key);
>> +        return;
>> +    }
>> +
>> +    /* Redirected traffic destined for LRP's IPs and the specified routing
>> +     * protocol ports to the port defined in 'routing-protocol-redirect'
>> +     * option.*/
>> +    for (size_t i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
>> +        const char *ip_s = op->lrp_networks.ipv4_addrs[i].addr_s;
>> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
>> +                                           redirected_protocols, false,
>> +                                           op->peer, lflows,match, actions);
>> +    }
>> +    for (size_t i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
>> +        const char *ip_s = op->lrp_networks.ipv6_addrs[i].addr_s;
>> +        apply_routing_protocols_redirect__(ip_s, redirect_port,
>> +                                           redirected_protocols, true,
>> +                                           op->peer, lflows,match, actions);
>> +    }
>> +
>> +    /* Drop ARP replies and IPv6 RA/NA packets originating from
>> +     * 'routing-protocol-redirect' LSP. As this port shares IP and MAC
>> +     * addresses with LRP, we don't want to create duplicates.*/
>> +    ds_clear(match);
>> +    ds_put_format(match, "inport == \"%s\" && arp.op == 2", redirect_port);
>> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
>> +                  ds_cstr(match),
>> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
>> +                  op->peer->lflow_ref);
>> +
>> +    ds_clear(match);
>> +    ds_put_format(match, "inport == \"%s\" && nd_na", redirect_port);
>> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
>> +                  ds_cstr(match),
>> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
>> +                  op->peer->lflow_ref);
>> +
>> +    ds_clear(match);
>> +    ds_put_format(match, "inport == \"%s\" && nd_ra", redirect_port);
>> +    ovn_lflow_add(lflows, op->peer->od, S_SWITCH_IN_CHECK_PORT_SEC, 80,
>> +                  ds_cstr(match),
>> +                  REGBIT_PORT_SEC_DROP " = 1; next;",
>> +                  op->peer->lflow_ref);
>> +}
>> +
>>  /* This function adds ARP resolve flows related to a LSP. */
>>  static void
>>  build_arp_resolve_flows_for_lsp(
>> @@ -16900,6 +17123,8 @@ build_lswitch_and_lrouter_iterate_by_lrp(struct ovn_port *op,
>>                                  op->lflow_ref);
>>      build_lrouter_icmp_packet_toobig_admin_flows(op, lsi->lflows, &lsi->match,
>>                                                   &lsi->actions, op->lflow_ref);
>> +    build_lrouter_routing_protocol_redirect(op, lsi->lflows,
>> +                                            &lsi->match, &lsi->actions);
>>  }
>>    static void *
>> diff --git a/northd/northd.h b/northd/northd.h
>> index e04ec5856..9e326b746 100644
>> --- a/northd/northd.h
>> +++ b/northd/northd.h
>> @@ -93,6 +93,13 @@ ovn_datapath_find_by_key(struct hmap *datapaths, uint32_t dp_key);
>>    bool od_has_lb_vip(const struct ovn_datapath *od);
>>  +/* List of routing and routing-related protocols which
>> + * OVN is capable of redirecting from LRP to specific LSP. */
>> +enum redirected_routing_protcol_flag_type {
>> +    REDIRECT_BGP = (1 << 0),
>> +    REDIRECT_BFD = (1 << 1),
>> +};
>> +
>>  struct tracked_ovn_ports {
>>      /* tracked created ports.
>>       * hmapx node data is 'struct ovn_port *' */
>> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
>> index 3abd5f75b..ede38882a 100644
>> --- a/northd/ovn-northd.8.xml
>> +++ b/northd/ovn-northd.8.xml
>> @@ -284,6 +284,32 @@
>>          dropped in the next stage.
>>        </li>
>>  +      <li>
>> +        <p>
>> +          For each logical port that's defined as a target of routing protocol
>> +          redirecting (via <code>routing-protocol-redirect</code> option set on
>> +          Logical Router Port), a filter is set in place that disallows
>> +          following traffic exiting this port:
>> +        </p>
>> +        <ul>
>> +          <li>
>> +            ARP replies
>> +          </li>
>> +          <li>
>> +            IPv6 Neighbor Discovery - Router Advertisements
>> +          </li>
>> +          <li>
>> +            IPv6 Neighbor Discovery - Neighbor Advertisements
>> +          </li>
>> +        </ul>
>> +        <p>
>> +          Since this port shares IP and MAC addresses with the Logical Router
>> +          Port, we wan't to prevent duplicate replies and advertisements. This
>> +          is achieved by a rule with priority 80 that sets
>> +          <code>REGBIT_PORT_SEC_DROP" = 1; next;"</code>.
>> +        </p>
>> +      </li>
>> +
>>        <li>
>>          For each (enabled) vtep logical port, a priority 70 flow is added which
>>          matches on all packets and applies the action
>> @@ -2002,6 +2028,34 @@ output;
>>          on the logical switch.
>>        </li>
>>  +      <li>
>> +        <p>
>> +          For any logical port that's defined as a target of routing protocol
>> +          redirecting (via <code>routing-protocol-redirect</code> option set on
>> +          Logical Router Port), we redirect the traffic related to protocols
>> +          specified in <code>routing-protocols</code> option. It's acoomplished
>> +          with following priority-100 flows:
>> +        </p>
>> +        <ul>
>> +          <li>
>> +            Flows that match Logical Router Port's IPs and destination port of
>> +            the routing daemon are redirected to this port to allow external
>> +            peers' connection to the daemon listening on this port.
>> +          </li>
>> +          <li>
>> +            Flows that match Logical Router Port's IPs and source port of
>> +            the routing daemon are redirected to this port to allow replies
>> +            from the peers.
>> +          </li>
>> +        </ul>
>> +        <p>
>> +          In addition to this, we add priority-100 rules that
>> +          <code>clone</code> ARP replies and IPv6 Neighbor Advertisements to
>> +          this port as well. These allow to build proper ARP/IPv6 neighbor
>> +          list on this port.
>> +        </p>
>> +      </li>
>> +
>>        <li>
>>          Priority-90 flows for transit switches that forward registered
>>          IP multicast traffic to their corresponding multicast group , which
>> diff --git a/ovn-nb.xml b/ovn-nb.xml
>> index bbda423a5..2836f58f5 100644
>> --- a/ovn-nb.xml
>> +++ b/ovn-nb.xml
>> @@ -3575,6 +3575,48 @@ or
>>          </p>
>>        </column>
>>  +      <column name="options" key="routing-protocol-redirect"
>> +              type='{"type": "string"}'>
>> +        <p>
>> +          NOTE: this feature is experimental and may be subject to
>> +          removal/change in the future.
>> +        </p>
>> +        <p>
>> +          This option expects a name of a Logical Switch Port that's present
>> +          in the peer's Logical Switch. If set, it causes any traffic
>> +          that's destined for Logical Router Port's IP addresses (including
>> +          its IPv6 LLA) and the ports associated with routing protocols defined
>> +          ip <code>routing-protocols</code> option, to be redirected
>> +          to the specified Logical Switch Port.
>> +
>> +          This allows external routing daemons to be bound to a port in OVN's
>> +          Logical Switch and act as if they were listening on Logical Router
>> +          Port's IP addresses.
>> +        </p>
>> +      </column>
>> +
>> +      <column name="options" key="routing-protocols" type='{"type": "string"}'>
>> +        <p>
>> +          NOTE: this feature is experimental and may be subject to
>> +          removal/change in the future.
>> +        </p>
>> +        <p>
>> +          This option expects a comma-separated list of routing, and
>> +          routing-related protocols, whose control plane traffic will be
>> +          redirected to a port specified in
>> +          <code>routing-protocol-redirect</code> option. Currently supported
>> +          options are:
>> +        </p>
>> +        <ul>
>> +          <li>
>> +            <code>BGP</code> (forwards TCP port 179)
>> +          </li>
>> +          <li>
>> +            <code>BFD</code> (forwards UDP port 3784)
>> +          </li>
>> +        </ul>
>> +      </column>
>> +
>>        <column name="options" key="gateway_mtu_bypass">
>>          <p>
>>            When configured, represents a match expression, in the same
>> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
>> index f2f42275a..bd05da3cd 100644
>> --- a/tests/ovn-northd.at
>> +++ b/tests/ovn-northd.at
>> @@ -13757,3 +13757,96 @@ AT_CHECK([grep -e "172.168.0.110" -e "172.168.0.120" -e "10.0.0.3" -e "20.0.0.3"
>>    AT_CLEANUP
>>  ])
>> +
>> +OVN_FOR_EACH_NORTHD_NO_HV([
>> +AT_SETUP([Routing protocol control plane redirect])
>> +ovn_start
>> +
>> +check ovn-sbctl chassis-add hv1 geneve 127.0.0.1
>> +
>> +check ovn-nbctl lr-add lr -- \
>> +    lrp-add lr lr-ls 02:ac:10:01:00:01 172.16.1.1/24
>> +check ovn-nbctl --wait=sb set logical_router lr options:chassis=hv1
>> +
>> +check ovn-nbctl ls-add ls -- \
>> +    lsp-add ls ls-lr -- \
>> +    lsp-set-type ls-lr router -- \
>> +    lsp-set-addresses ls-lr router -- \
>> +    lsp-set-options ls-lr router-port=lr-ls
>> +
>> +check ovn-nbctl lsp-add ls lsp-bgp -- \
>> +    lsp-set-addresses lsp-bgp unknown
>> +
>> +# Function that ensures that no redirect rules are installed.
>> +check_no_redirect() {
>> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "tcp.dst == 179|tcp.src == 179" | wc -l], [0], [0
>> +])
>> +
>> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep -E "priority=80" | wc -l], [0], [0
>> +])
>> +    check_no_bfd_redirect
>> +}
>> +
>> +# Function that ensures that no BFD redirect rules are installed.
>> +check_no_bfd_redirect() {
>> +    AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup  | grep -E "udp.dst == 3784|udp.src == 3784" | wc -l], [0], [0
>> +])
>> +}
>> +
>> +# By default, no rules related to routing protocol redirect are present
>> +check_no_redirect
>> +
>> +# Set "lsp-bgp" port as target of BGP control plane redirected traffic
>> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-bgp
>> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP
>> +
>> +# Check that BGP control plane traffic is redirected "lsp-bgp"
>> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "tcp.dst == 179|tcp.src == 179" | ovn_strip_lflows], [0], [dnl
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.dst == 179), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && tcp.src == 179), action=(outport = "lsp-bgp"; output;)
>> +])
>> +
>> +# Check that ARP/ND traffic is cloned to the "lsp-bgp"
>> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "arp.op == 2 && arp.tpa == 172.16.1.1" | ovn_strip_lflows], [0], [dnl
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(arp.op == 2 && arp.tpa == 172.16.1.1), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
>> +])
>> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep "&& nd_na" | ovn_strip_lflows], [0], [dnl
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && nd_na), action=(clone { outport = "lsp-bgp"; output; }; outport = "ls-lr"; output;)
>> +])
>> +
>> +# Check that at this point no BFD redirecting is present
>> +check_no_bfd_redirect
>> +
>> +# Add BFD traffic redirect
>> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
>> +
>> +# Check that BFD traffic is redirected to "lsp-bgp"
>> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_l2_lkup | grep -E "udp.dst == 3784|udp.src == 3784" | ovn_strip_lflows], [0], [dnl
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip4.dst == 172.16.1.1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.dst == 3784), action=(outport = "lsp-bgp"; output;)
>> +  table=??(ls_in_l2_lkup      ), priority=100  , match=(ip6.dst == fe80::ac:10ff:fe01:1 && udp.src == 3784), action=(outport = "lsp-bgp"; output;)
>> +])
>> +
>> +
>> +# Check that ARP replies and ND advertisements are blocked from exiting "lsp-bgp"
>> +AT_CHECK([ovn-sbctl dump-flows ls | grep ls_in_check_port_sec | grep "priority=80" | ovn_strip_lflows], [0], [dnl
>> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && arp.op == 2), action=(reg0[[15]] = 1; next;)
>> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_na), action=(reg0[[15]] = 1; next;)
>> +  table=??(ls_in_check_port_sec), priority=80   , match=(inport == "lsp-bgp" && nd_ra), action=(reg0[[15]] = 1; next;)
>> +])
>> +
>> +# Remove 'bgp-redirect' option from LRP and check that rules are removed
>> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocol-redirect
>> +check ovn-nbctl --wait=sb remove logical_router_port lr-ls options routing-protocols
>> +check_no_redirect
>> +
>> +# Set non-existent LSP as target of 'bgp-redirect' and check that no rules are added
>> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocol-redirect=lsp-foo
>> +check ovn-nbctl --wait=sb set logical_router_port lr-ls options:routing-protocols=BGP,BFD
>> +check_no_redirect
>> +
>> +AT_CLEANUP
>> +])
>> diff --git a/tests/system-ovn.at b/tests/system-ovn.at
>> index 7ba2e150b..c0adb8cc2 100644
>> --- a/tests/system-ovn.at
>> +++ b/tests/system-ovn.at
>> @@ -13504,3 +13504,123 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/failed to query port patch-.*/d
>>    AT_CLEANUP
>>  ])
>> +
>> +OVN_FOR_EACH_NORTHD([
>> +AT_SETUP([Routing protocol redirect])
>> +AT_SKIP_IF([test $HAVE_NC = no])
>> +
>> +ovn_start
>> +OVS_TRAFFIC_VSWITCHD_START()
>> +
>> +ADD_BR([br-int])
>> +ADD_BR([br-ext])
>> +
>> +check ovs-ofctl add-flow br-ext action=normal
>> +# Set external-ids in br-int needed for ovn-controller
>> +check ovs-vsctl \
>> +        -- set Open_vSwitch . external-ids:system-id=hv1 \
>> +        -- set Open_vSwitch . external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
>> +        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
>> +        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
>> +        -- set bridge br-int fail-mode=secure other-config:disable-in-band=true
>> +
>> +# Start ovn-controller
>> +start_daemon ovn-controller
>> +
>> +check ovn-nbctl lr-add R1 \
>> +    -- set Logical_Router R1 options:chassis=hv1
>> +
>> +check ovn-nbctl ls-add public
>> +check ovn-nbctl ls-add bar
>> +
>> +check ovn-nbctl lrp-add R1 rp-public 00:00:02:01:02:03 172.16.1.1/24
>> +check ovn-nbctl lrp-add R1 rp-bar 00:00:ff:00:00:01 192.168.10.1/24
>> +
>> +check ovn-nbctl lsp-add public public-rp -- set Logical_Switch_Port public-rp \
>> +    type=router options:router-port=rp-public \
>> +    -- lsp-set-addresses public-rp router
>> +
>> +check ovn-nbctl lsp-add bar bar-rp -- set Logical_Switch_Port bar-rp \
>> +    type=router options:router-port=rp-bar \
>> +    -- lsp-set-addresses bar-rp router
>> +
>> +check ovn-nbctl lsp-add public bgp-daemon \
>> +    -- lsp-set-addresses bgp-daemon unknown
>> +
>> +# Setup container "bar1" representing host on an internal network
>> +ADD_NAMESPACES(bar1)
>> +ADD_VETH(bar1, bar1, br-int, "192.168.10.2/24", "00:00:ff:ff:ff:01", \
>> +         "192.168.10.1")
>> +check ovn-nbctl lsp-add bar bar1 \
>> +    -- lsp-set-addresses bar1 "00:00:ff:ff:ff:01 192.168.10.2"
>> +
>> +# Setup SNAT for the internal host
>> +AT_CHECK([ovn-nbctl lr-nat-add R1 snat 172.16.1.1 192.168.10.2])
>> +
>> +# Configure external connectivity
>> +AT_CHECK([ovs-vsctl set Open_vSwitch . external-ids:ovn-bridge-mappings=phynet:br-ext])
>> +check ovn-nbctl lsp-add public public1 \
>> +        -- lsp-set-addresses public1 unknown \
>> +        -- lsp-set-type public1 localnet \
>> +        -- lsp-set-options public1 network_name=phynet
>> +
>> +check ovn-nbctl --wait=hv sync
>> +
>> +# Set option that redirects BGP traffic to a LSP "bgp-daemon"
>> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocol-redirect=bgp-daemon
>> +check ovn-nbctl --wait=sb set logical_router_port rp-public options:routing-protocols=BGP
>> +
>> +# Create "bgp-daemon" interface in a namespace with IP and MAC matching LRP "rp-public"
>> +ADD_NAMESPACES(bgp-daemon)
>> +ADD_VETH(bgp-daemon, bgp-daemon, br-int, "172.16.1.1/24", "00:00:02:01:02:03")
>> +
>> +ADD_NAMESPACES(ext-foo)
>> +ADD_VETH(ext-foo, ext-foo, br-ext, "172.16.1.100/24", "00:10:10:01:02:13", \
>> +         "172.16.1.1")
>> +
>> +# Flip the interface down/up to get proper IPv6 LLA
>> +NS_EXEC([bgp-daemon], [ip link set down bgp-daemon])
>> +NS_EXEC([bgp-daemon], [ip link set up bgp-daemon])
>> +NS_EXEC([ext-foo], [ip link set down ext-foo])
>> +NS_EXEC([ext-foo], [ip link set up ext-foo])
>> +
>> +# Wait until IPv6 LLA loses the "tentative" flag otherwise it can't be bound to.
>> +OVS_WAIT_UNTIL([NS_EXEC([bgp-daemon], [ip a show dev bgp-daemon | grep "fe80::" | grep -v tentative])])
>> +OVS_WAIT_UNTIL([NS_EXEC([ext-foo], [ip a show dev ext-foo | grep "fe80::" | grep -v tentative])])
>> +
>> +# Verify that BGP control plane traffic is delivered to the "bgp-daemon"
>> +# interface on both IPv4 and IPv6 LLA addresses
>> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -k 172.16.1.1 179], [bgp_v4.pid])
>> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only 172.16.1.1 179])
>> +
>> +NETNS_DAEMONIZE([bgp-daemon], [nc -l -6 -k fe80::200:2ff:fe01:203%bgp-daemon 179], [bgp_v6.pid])
>> +NS_CHECK_EXEC([ext-foo], [echo "TCP test" | nc --send-only -6 fe80::200:2ff:fe01:203%ext-foo 179])
>> +
>> +# Verify connection in other direction. i.e when daemon running on "bgp-daemon" port
>> +# makes a client connection to its peer
>> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 179], [reply_bgp_v4.pid])
>> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only 172.16.1.100 179])
>> +
>> +NETNS_DAEMONIZE([ext-foo], [nc -l -6 -k fe80::210:10ff:fe01:213%ext-foo 179], [reply_bgp_v6.pid])
>> +NS_CHECK_EXEC([bgp-daemon], [echo "TCP test" | nc --send-only -6 fe80::210:10ff:fe01:213%bgp-daemon 179])
>> +
>> +# Verify that hosts on the internal network can reach external networks
>> +NETNS_DAEMONIZE([ext-foo], [nc -l -k 172.16.1.100 2222], [nc_external.pid])
>> +NS_CHECK_EXEC([bar1], [echo "TCP test" | nc -w 1 --send-only 172.16.1.100 2222])
>> +
>> +OVS_APP_EXIT_AND_WAIT([ovn-controller])
>> +
>> +as ovn-sb
>> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
>> +
>> +as ovn-nb
>> +OVS_APP_EXIT_AND_WAIT([ovsdb-server])
>> +
>> +as northd
>> +OVS_APP_EXIT_AND_WAIT([ovn-northd])
>> +
>> +as
>> +OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
>> +/.*terminating with signal 15.*/d"])
>> +AT_CLEANUP
>> +])
>