On Fri, Nov 24, 2023 at 4:57 PM <[email protected]> wrote:

> From: Jacob Tanenbaum <[email protected]>
>
> Currently for every LSP two DHCP responder flows are created. These two
> flows are almost exactly the same differing only in the match.
>
> ex.
> Unicast flow (for RENEW/REBIND):
> "match":"inport == \"0e4b7821-b5ae-4bff-9424-d7245c679150\" && eth.src ==
> fa:16:3e:68:5e:c1 && ip4.src == 1.65.5.169 && ip4.dst == {1.65.5.1,
> 255.255.255.255} && udp.src == 68 && udp.dst == 67"
>
> Broadcast flow (for DISCOVER):
> "match":"inport == \"0e4b7821-b5ae-4bff-9424-d7245c679150\" && eth.src ==
> fa:16:3e:68:5e:c1 && ip4.src == 0.0.0.0 && ip4.dst == 255.255.255.255 &&
> udp.src == 68 && udp.dst == 67"
>
> I consolidated the flows to use the conjunctive match (ip4.src ==
> {1.65.5.169, 0.0.0.0}  && ip4.dst == {1.65.5.1, 255.255.255.255})
>
> there is potential for a faulty DHCP discovery and DHCP Request packet
> getting through
>   - added a check in pinctrl.c to check for illegal dhcp discovery packet
> sending to host
>
> Submitted-at: https://github.com/ovn-org/ovn/pull/224
> Signed-off-by: Jacob Tanenbaum <[email protected]>
> Acked-by: Dumitru Ceara <[email protected]>
> ---
>  controller/pinctrl.c |  5 +++++
>  northd/northd.c      | 23 ++---------------------
>  tests/ovn-northd.at  |  9 +++------
>  tests/ovn.at         |  4 ++--
>  4 files changed, 12 insertions(+), 29 deletions(-)
>
> diff --git a/controller/pinctrl.c b/controller/pinctrl.c
> index 62cf4da324..2f2f945b71 100644
> --- a/controller/pinctrl.c
> +++ b/controller/pinctrl.c
> @@ -2039,6 +2039,11 @@ pinctrl_handle_put_dhcp_opts(
>      switch (*in_dhcp_msg_type) {
>      case DHCP_MSG_DISCOVER:
>          msg_type = DHCP_MSG_OFFER;
> +        if (in_flow->nw_dst != htonl(INADDR_BROADCAST)) {
> +            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +            VLOG_WARN_RL(&rl, "DHCP DISCOVER must be Broadcast");
> +            goto exit;
> +        }
>          break;
>      case DHCP_MSG_REQUEST: {
>          msg_type = DHCP_MSG_ACK;
> diff --git a/northd/northd.c b/northd/northd.c
> index e93d0c8f82..d0fe1929fc 100644
> --- a/northd/northd.c
> +++ b/northd/northd.c
> @@ -6805,7 +6805,8 @@ build_dhcpv4_action(struct ovn_port *op, ovs_be32
> offer_ip,
>                    server_mac, server_ip);
>
>      ds_put_format(ipv4_addr_match,
> -                  "ip4.src == "IP_FMT" && ip4.dst == {%s,
> 255.255.255.255}",
> +                  "(ip4.src == {"IP_FMT", 0.0.0.0} "
> +                  "&& ip4.dst == {%s, 255.255.255.255})",
>                    IP_ARGS(offer_ip), server_ip);
>      smap_destroy(&dhcpv4_options);
>      return true;
> @@ -9438,27 +9439,7 @@ build_dhcpv4_options_flows(struct ovn_port *op,
>                  op, lsp_addrs->ipv4_addrs[j].addr,
>                  &options_action, &response_action, &ipv4_addr_match)) {
>              ds_clear(&match);
> -            ds_put_format(
> -                &match, "inport == %s && eth.src == %s && "
> -                "ip4.src == 0.0.0.0 && ip4.dst == 255.255.255.255 && "
> -                "udp.src == 68 && udp.dst == 67",
> -                inport->json_key, lsp_addrs->ea_s);
>
> -            if (is_external) {
> -                ds_put_format(&match, " && is_chassis_resident(%s)",
> -                              op->json_key);
> -            }
> -
> -            ovn_lflow_add_with_hint__(lflows, op->od,
> -                                      S_SWITCH_IN_DHCP_OPTIONS, 100,
> -                                      ds_cstr(&match),
> -                                      ds_cstr(&options_action),
> -                                      inport->key,
> -                                      copp_meter_get(COPP_DHCPV4_OPTS,
> -                                                     op->od->nbs->copp,
> -                                                     meter_groups),
> -                                      &op->nbsp->dhcpv4_options->header_);
> -            ds_clear(&match);
>              /* Allow ip4.src = OFFER_IP and
>               * ip4.dst = {SERVER_IP, 255.255.255.255} for the below
>               * cases
> diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
> index 66ea495e5d..b0e464e77c 100644
> --- a/tests/ovn-northd.at
> +++ b/tests/ovn-northd.at
> @@ -4768,8 +4768,7 @@ AT_CAPTURE_FILE([sw0flows])
>
>  AT_CHECK([grep -w "ls_in_dhcp_options" sw0flows | sort | sed
> 's/table=../table=??/'], [0], [dnl
>    table=??(ls_in_dhcp_options ), priority=0    , match=(1), action=(next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 0.0.0.0 &&
> ip4.dst == 255.255.255.255 && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "foo",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 10.0.0.2 &&
> ip4.dst == {10.0.0.1, 255.255.255.255} && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "foo",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> +  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && (ip4.src == {10.0.0.2,
> 0.0.0.0} && ip4.dst == {10.0.0.1, 255.255.255.255}) && udp.src == 68 &&
> udp.dst == 67), action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2,
> hostname = "foo", lease_time = 3600, netmask = 255.255.255.0, router =
> 10.0.0.1, server_id = 10.0.0.1); next;)
>  ])
>
>  check ovn-nbctl --wait=sb lsp-set-options sw0-port1 hostname="\"port1\""
> @@ -4778,8 +4777,7 @@ AT_CAPTURE_FILE([sw0flows])
>
>  AT_CHECK([grep -w "ls_in_dhcp_options" sw0flows | sort | sed
> 's/table=../table=??/'], [0], [dnl
>    table=??(ls_in_dhcp_options ), priority=0    , match=(1), action=(next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 0.0.0.0 &&
> ip4.dst == 255.255.255.255 && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "port1",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 10.0.0.2 &&
> ip4.dst == {10.0.0.1, 255.255.255.255} && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "port1",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> +  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && (ip4.src == {10.0.0.2,
> 0.0.0.0} && ip4.dst == {10.0.0.1, 255.255.255.255}) && udp.src == 68 &&
> udp.dst == 67), action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2,
> hostname = "port1", lease_time = 3600, netmask = 255.255.255.0, router =
> 10.0.0.1, server_id = 10.0.0.1); next;)
>  ])
>
>  ovn-nbctl dhcp-options-set-options $CIDR_UUID  lease_time=3600
>  router=10.0.0.1   server_id=10.0.0.1   server_mac=c0:ff:ee:00:00:01
> @@ -4789,8 +4787,7 @@ AT_CAPTURE_FILE([sw0flows])
>
>  AT_CHECK([grep -w "ls_in_dhcp_options" sw0flows | sort | sed
> 's/table=../table=??/'], [0], [dnl
>    table=??(ls_in_dhcp_options ), priority=0    , match=(1), action=(next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 0.0.0.0 &&
> ip4.dst == 255.255.255.255 && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "bar",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> -  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && ip4.src == 10.0.0.2 &&
> ip4.dst == {10.0.0.1, 255.255.255.255} && udp.src == 68 && udp.dst == 67),
> action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2, hostname = "bar",
> lease_time = 3600, netmask = 255.255.255.0, router = 10.0.0.1, server_id =
> 10.0.0.1); next;)
> +  table=??(ls_in_dhcp_options ), priority=100  , match=(inport ==
> "sw0-port1" && eth.src == 50:54:00:00:00:01 && (ip4.src == {10.0.0.2,
> 0.0.0.0} && ip4.dst == {10.0.0.1, 255.255.255.255}) && udp.src == 68 &&
> udp.dst == 67), action=(reg0[[3]] = put_dhcp_opts(offerip = 10.0.0.2,
> hostname = "bar", lease_time = 3600, netmask = 255.255.255.0, router =
> 10.0.0.1, server_id = 10.0.0.1); next;)
>  ])
>
>  AT_CLEANUP
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 17ad1fb243..b2d69ecccf 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -19639,7 +19639,7 @@ wait_for_ports_up ls1-lp_ext1
>  as hv1 ovs-ofctl dump-flows br-int > brintflows
>  AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | \
>  grep controller | grep "0a.00.00.06" | grep reg14=0x$ln_public_key | \
> -wc -l], [0], [3
> +wc -l], [0], [1
>  ])
>  AT_CHECK([as hv1 ovs-ofctl dump-flows br-int | \
>  grep controller | grep tp_src=546 | grep \
> @@ -19891,7 +19891,7 @@ wait_for_ports_up ls1-lp_ext1
>  # There should be OF flows for DHCP4/v6 for the ls1-lp_ext1 port in hv2
>  AT_CHECK([as hv2 ovs-ofctl dump-flows br-int | \
>  grep controller | grep "0a.00.00.06" | grep reg14=0x$ln_public_key | \
> -wc -l], [0], [3
> +wc -l], [0], [1
>  ])
>  AT_CHECK([as hv2 ovs-ofctl dump-flows br-int | \
>  grep controller | grep tp_src=546 | grep \
> --
> 2.41.0
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>
>

Can we please backport this patch to ovn-23.09. This is needed in order to
backport the following fix:

commit f74b38f774061e7a56c125b45c8761e9ddc43a03
Author: Lorenzo Bianconi <[email protected]>
Date:   Thu Sep 12 18:40:02 2024 +0200

    controller: Accept unicast dhcp-discover in
pinctrl_handle_put_dhcp_opts().

    According to RFC 2131 section 4.4.4, when the DHCP client knows the
    address of a DHCP server, in either INIT or REBOOTING state, the client
    may use that address in the DHCPDISCOVER or DHCPREQUEST rather than the
    IP broadcast address. Fix pinctrl_handle_put_dhcp_opts implementation
    according to the RFC 2131.

    Reported-at: https://issues.redhat.com/browse/FDP-765
    Signed-off-by: Lorenzo Bianconi <[email protected]>
    Acked-by: Mark Michelson <[email protected]>
    Signed-off-by: Numan Siddique <[email protected]>

More info reported here: https://issues.redhat.com/browse/FDP-765

Regards,
Lorenzo
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