On Tue, May 8, 2018 at 1:20 PM, Miguel Angel Ajo Pelayo <[email protected]
> wrote:

> Thank you Numan!
>
> It took me a bit to find what the "RSO"  flag was, because they are R, S
> and O, may be we can change that in the commit, or reference the
> RFC/section  (RFC4861 page 23).
>

Ack. I will update the commit message and send v2.


>
>      R              Router flag.  When set, the R-bit indicates that
>                      the sender is a router.  The R-bit is used by
>                      Neighbor Unreachability Detection to detect a
>                      router that changes to a host.
>
>       S              Solicited flag.  When set, the S-bit indicates that
>                      the advertisement was sent in response to a
>                      Neighbor Solicitation from the Destination address.
>                      The S-bit is used as a reachability confirmation
>                      for Neighbor Unreachability Detection.  It MUST NOT
>                      be set in multicast advertisements or in
>                      unsolicited unicast advertisements.
>
>       O              Override flag.  When set, the O-bit indicates that
>                      the advertisement should override an existing cache
>                      entry and update the cached link-layer address.
>                      When it is not set the advertisement will not
>                      update a cached link-layer address though it will
>                      update an existing Neighbor Cache entry for which
>                      no link-layer address is known.  It SHOULD NOT be
>                      set in solicited advertisements for anycast
>                      addresses and in solicited proxy advertisements.
>                      It SHOULD be set in other solicited advertisements
>                      and in unsolicited advertisements.
>
>
>
>
> And same question Mark did.
>
> Thanks for handling this, good work :)
>
> On Mon, May 7, 2018 at 9:16 PM Mark Michelson <[email protected]> wrote:
>
>> Hi Numan, thanks for the fix.
>>
>> Out of curiosity, why did you add a new action instead of adding a new
>> logical field (something like nd.rso)?
>>
>
The logical flow which uses nd_na looks like

  table=11(ls_in_arp_rsp      ), priority=50   , match=(nd_ns && ip6.dst ==
{2002::f816:3eff:fefe:9e2e, ff02::1:fffe:9e2e} && nd.target ==
2002::f816:3eff:fefe:9e2e), action=(nd_na { eth.src = fa:16:3e:fe:9e:2e;
ip6.src = 2002::f816:3eff:fefe:9e2e; nd.target = 2002::f816:3eff:fefe:9e2e;
nd.tll = fa:16:3e:fe:9e:2e; outport = inport; flags.loopback = 1; output;
};)


I suppose you are suggesting to have something like - " nd_na { .., nd.rso
= router ..} ". All the inner logical fields are defined in expr symtab
table [1]. But we cannot add nd.rso there as there is no corresponding ovs
field to modify the ICMPv6 flags of a packet.

>From the email discussion here [2] I suppose Zak is working to add this
feature. Once we have this support, we can make use of that in OVN. Right
now IPv6 feature is blocked in Openstack + OVN  because of this issue so we
need this fix.

[1] - https://github.com/openvswitch/ovs/blob/master/
ovn/lib/logical-fields.c#L205
[2] -
https://mail.openvswitch.org/pipermail/ovs-discuss/2018-May/046662.html

https://mail.openvswitch.org/pipermail/ovs-discuss/2018-April/046528.html


Thanks
Numan




>
>> On 05/07/2018 02:36 PM, [email protected] wrote:
>> > From: Numan Siddique <[email protected]>
>> >
>> > Presently when a VM's IPv6 stack sends a Neighbor Solicitation request
>> for its
>> > router IP, (mostly when the ND cache entry for the router is in STALE
>> state)
>> > ovn-controller responds with a Neighbor Adv packet (using the action
>> nd_na).
>> > But it doesn't set 'ND_RSO_ROUTER' in the RSO flags. Because of which,
>> the
>> > VM deletes the default route. The default route gets added again when
>> the next
>> > RA is received (but would again gets deleted if its sends NS request).
>> And this
>> > results in disruption of IPv6 traffic.
>> >
>> > This patch addresses this issue by adding a new action 'nd_na_router'
>> which is
>> > same as 'nd_na' but it sets the 'ND_RSO_ROUTER' in the RSO flags.
>> ovn-northd
>> > uses this action. A new action is added instead of modifying the
>> existing 'nd_na'
>> > action. This is because
>> >    - We cannot set the RSO flags in the "nd_na { ..actions .. }"
>> >    - It would be ugly to have something like nd_na { router_flags,
>> ...actions .. }
>> >
>> > (Please note: There are 3 'Line length is >79-characters' warnings in
>> ovn.at which
>> > I couldn't resolve.)
>> >
>> > Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1567735
>> > CC: Justin Pettit <[email protected]>
>> > CC: Mark Michelson <[email protected]>
>> > Signed-off-by: Numan Siddique <[email protected]>
>> > ---
>> >   include/ovn/actions.h     |  7 +++++++
>> >   ovn/controller/pinctrl.c  | 23 +++++++++++++++--------
>> >   ovn/lib/actions.c         | 22 ++++++++++++++++++++++
>> >   ovn/northd/ovn-northd.c   |  2 +-
>> >   ovn/utilities/ovn-trace.c |  1 +
>> >   tests/ovn.at              |  5 +++++
>> >   6 files changed, 51 insertions(+), 9 deletions(-)
>> >
>> > diff --git a/include/ovn/actions.h b/include/ovn/actions.h
>> > index fb8f51509..638465193 100644
>> > --- a/include/ovn/actions.h
>> > +++ b/include/ovn/actions.h
>> > @@ -68,6 +68,7 @@ struct ovn_extend_table;
>> >       OVNACT(ICMP6,             ovnact_nest)            \
>> >       OVNACT(TCP_RESET,         ovnact_nest)            \
>> >       OVNACT(ND_NA,             ovnact_nest)            \
>> > +    OVNACT(ND_NA_ROUTER,      ovnact_nest)            \
>> >       OVNACT(GET_ARP,           ovnact_get_mac_bind)    \
>> >       OVNACT(PUT_ARP,           ovnact_put_mac_bind)    \
>> >       OVNACT(GET_ND,            ovnact_get_mac_bind)    \
>> > @@ -444,6 +445,12 @@ enum action_opcode {
>> >        * The actions, in OpenFlow 1.3 format, follow the action_header.
>> >        */
>> >       ACTION_OPCODE_TCP_RESET,
>> > +
>> > +    /* "nd_na_router { ...actions... }" with rso flag 'ND_RSO_ROUTER'
>> set.
>> > +        *
>> > +        * The actions, in OpenFlow 1.3 format, follow the
>> action_header.
>> > +        */
>> > +    ACTION_OPCODE_ND_NA_ROUTER,
>> >   };
>> >
>> >   /* Header. */
>> > diff --git a/ovn/controller/pinctrl.c b/ovn/controller/pinctrl.c
>> > index 6e6aa1caa..305f20649 100644
>> > --- a/ovn/controller/pinctrl.c
>> > +++ b/ovn/controller/pinctrl.c
>> > @@ -81,7 +81,8 @@ static void send_garp_run(struct controller_ctx *ctx,
>> >                             struct sset *active_tunnels);
>> >   static void pinctrl_handle_nd_na(const struct flow *ip_flow,
>> >                                    const struct match *md,
>> > -                                 struct ofpbuf *userdata);
>> > +                                 struct ofpbuf *userdata,
>> > +                                 bool is_router);
>> >   static void reload_metadata(struct ofpbuf *ofpacts,
>> >                               const struct match *md);
>> >   static void pinctrl_handle_put_nd_ra_opts(
>> > @@ -1154,7 +1155,11 @@ process_packet_in(const struct ofp_header *msg,
>> struct controller_ctx *ctx)
>> >           break;
>> >
>> >       case ACTION_OPCODE_ND_NA:
>> > -        pinctrl_handle_nd_na(&headers, &pin.flow_metadata, &userdata);
>> > +        pinctrl_handle_nd_na(&headers, &pin.flow_metadata, &userdata,
>> false);
>> > +        break;
>> > +
>> > +    case ACTION_OPCODE_ND_NA_ROUTER:
>> > +        pinctrl_handle_nd_na(&headers, &pin.flow_metadata, &userdata,
>> true);
>> >           break;
>> >
>> >       case ACTION_OPCODE_PUT_ND:
>> > @@ -2308,7 +2313,7 @@ reload_metadata(struct ofpbuf *ofpacts, const
>> struct match *md)
>> >
>> >   static void
>> >   pinctrl_handle_nd_na(const struct flow *ip_flow, const struct match
>> *md,
>> > -                     struct ofpbuf *userdata)
>> > +                     struct ofpbuf *userdata, bool is_router)
>> >   {
>> >       /* This action only works for IPv6 ND packets, and the switch
>> should only
>> >        * send us ND packets this way, but check here just to be sure. */
>> > @@ -2322,13 +2327,15 @@ pinctrl_handle_nd_na(const struct flow
>> *ip_flow, const struct match *md,
>> >       struct dp_packet packet;
>> >       dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub);
>> >
>> > -    /* xxx These flags are not exactly correct.  Look at section 7.2.4
>> > -     * xxx of RFC 4861.  For example, we need to set ND_RSO_ROUTER for
>> > -     * xxx router's interfaces and ND_RSO_SOLICITED only if it was
>> > -     * xxx requested. */
>> > +    /* These flags are not exactly correct.  Look at section 7.2.4
>> > +     * of RFC 4861. */
>> > +    uint32_t rso_flags = ND_RSO_SOLICITED | ND_RSO_OVERRIDE;
>> > +    if (is_router) {
>> > +        rso_flags |= ND_RSO_ROUTER;
>> > +    }
>> >       compose_nd_na(&packet, ip_flow->dl_dst, ip_flow->dl_src,
>> >                     &ip_flow->nd_target, &ip_flow->ipv6_src,
>> > -                  htonl(ND_RSO_SOLICITED | ND_RSO_OVERRIDE));
>> > +                  htonl(rso_flags));
>> >
>> >       /* Reload previous packet metadata and set actions from userdata.
>> */
>> >       set_actions_and_enqueue_msg(&packet, md, userdata);
>> > diff --git a/ovn/lib/actions.c b/ovn/lib/actions.c
>> > index a6945812d..0669cc1c9 100644
>> > --- a/ovn/lib/actions.c
>> > +++ b/ovn/lib/actions.c
>> > @@ -1155,6 +1155,12 @@ parse_ND_NA(struct action_context *ctx)
>> >       parse_nested_action(ctx, OVNACT_ND_NA, "nd_ns");
>> >   }
>> >
>> > +static void
>> > +parse_ND_NA_ROUTER(struct action_context *ctx)
>> > +{
>> > +    parse_nested_action(ctx, OVNACT_ND_NA_ROUTER, "nd_ns");
>> > +}
>> > +
>> >   static void
>> >   parse_ND_NS(struct action_context *ctx)
>> >   {
>> > @@ -1206,6 +1212,12 @@ format_ND_NA(const struct ovnact_nest *nest,
>> struct ds *s)
>> >       format_nested_action(nest, "nd_na", s);
>> >   }
>> >
>> > +static void
>> > +format_ND_NA_ROUTER(const struct ovnact_nest *nest, struct ds *s)
>> > +{
>> > +    format_nested_action(nest, "nd_na_router", s);
>> > +}
>> > +
>> >   static void
>> >   format_ND_NS(const struct ovnact_nest *nest, struct ds *s)
>> >   {
>> > @@ -1282,6 +1294,14 @@ encode_ND_NA(const struct ovnact_nest *on,
>> >       encode_nested_actions(on, ep, ACTION_OPCODE_ND_NA, ofpacts);
>> >   }
>> >
>> > +static void
>> > +encode_ND_NA_ROUTER(const struct ovnact_nest *on,
>> > +             const struct ovnact_encode_params *ep,
>> > +             struct ofpbuf *ofpacts)
>> > +{
>> > +    encode_nested_actions(on, ep, ACTION_OPCODE_ND_NA_ROUTER, ofpacts);
>> > +}
>> > +
>> >   static void
>> >   encode_ND_NS(const struct ovnact_nest *on,
>> >                const struct ovnact_encode_params *ep,
>> > @@ -2305,6 +2325,8 @@ parse_action(struct action_context *ctx)
>> >           parse_TCP_RESET(ctx);
>> >       } else if (lexer_match_id(ctx->lexer, "nd_na")) {
>> >           parse_ND_NA(ctx);
>> > +    } else if (lexer_match_id(ctx->lexer, "nd_na_router")) {
>> > +        parse_ND_NA_ROUTER(ctx);
>> >       } else if (lexer_match_id(ctx->lexer, "nd_ns")) {
>> >           parse_ND_NS(ctx);
>> >       } else if (lexer_match_id(ctx->lexer, "get_arp")) {
>> > diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
>> > index ce472a536..b157cd1eb 100644
>> > --- a/ovn/northd/ovn-northd.c
>> > +++ b/ovn/northd/ovn-northd.c
>> > @@ -5104,7 +5104,7 @@ build_lrouter_flows(struct hmap *datapaths,
>> struct hmap *ports,
>> >               ds_clear(&actions);
>> >               ds_put_format(&actions,
>> >                             "put_nd(inport, ip6.src, nd.sll); "
>> > -                          "nd_na { "
>> > +                          "nd_na_router { "
>> >                             "eth.src = %s; "
>> >                             "ip6.src = %s; "
>> >                             "nd.target = %s; "
>> > diff --git a/ovn/utilities/ovn-trace.c b/ovn/utilities/ovn-trace.c
>> > index 9c19b5b9a..1fd48f22e 100644
>> > --- a/ovn/utilities/ovn-trace.c
>> > +++ b/ovn/utilities/ovn-trace.c
>> > @@ -1927,6 +1927,7 @@ trace_actions(const struct ovnact *ovnacts,
>> size_t ovnacts_len,
>> >               break;
>> >
>> >           case OVNACT_ND_NA:
>> > +        case OVNACT_ND_NA_ROUTER:
>> >               execute_nd_na(ovnact_get_ND_NA(a), dp, uflow, table_id,
>> pipeline,
>> >                             super);
>> >               break;
>> > diff --git a/tests/ovn.at b/tests/ovn.at
>> > index 4a5316510..2c0ae9877 100644
>> > --- a/tests/ovn.at
>> > +++ b/tests/ovn.at
>> > @@ -1033,6 +1033,11 @@ nd_na { eth.src = 12:34:56:78:9a:bc; nd.tll =
>> 12:34:56:78:9a:bc; outport = inpor
>> >       formats as nd_na { eth.src = 12:34:56:78:9a:bc; nd.tll =
>> 12:34:56:78:9a:bc; outport = inport; inport = ""; output; };
>> >       encodes as controller(userdata=00.00.00.
>> 03.00.00.00.00.00.19.00.10.80.00.08.06.12.34.56.78.9a.bc.00.
>> 00.00.19.00.10.80.00.42.06.12.34.56.78.9a.bc.00.00.ff.ff.00.
>> 18.00.00.23.20.00.06.00.20.00.00.00.00.00.01.1c.04.00.01.1e.
>> 04.00.19.00.10.00.01.1c.04.00.00.00.00.00.00.00.00.ff.ff.00.
>> 10.00.00.23.20.00.0e.ff.f8.40.00.00.00)
>> >       has prereqs nd_ns
>> > +# nd_na_router
>> > +nd_na_router { eth.src = 12:34:56:78:9a:bc; nd.tll =
>> 12:34:56:78:9a:bc; outport = inport; inport = ""; /* Allow sending out
>> inport. */ output; };
>> > +    formats as nd_na_router { eth.src = 12:34:56:78:9a:bc; nd.tll =
>> 12:34:56:78:9a:bc; outport = inport; inport = ""; output; };
>> > +    encodes as controller(userdata=00.00.00.
>> 0c.00.00.00.00.00.19.00.10.80.00.08.06.12.34.56.78.9a.bc.00.
>> 00.00.19.00.10.80.00.42.06.12.34.56.78.9a.bc.00.00.ff.ff.00.
>> 18.00.00.23.20.00.06.00.20.00.00.00.00.00.01.1c.04.00.01.1e.
>> 04.00.19.00.10.00.01.1c.04.00.00.00.00.00.00.00.00.ff.ff.00.
>> 10.00.00.23.20.00.0e.ff.f8.40.00.00.00)
>> > +    has prereqs nd_ns
>> >
>> >   # get_nd
>> >   get_nd(outport, ip6.dst);
>> >
>>
>> _______________________________________________
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>>
>
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