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).
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)?
>
> 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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