Merge pull request FRRouting#15259 from dmytroshytyi-6WIND/nexthop_re…

…solution

zebra: add LSP entry to nexthop via recursive (part 2)

bgpd/bgp_route.c

@@ -4634,7 +4634,22 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
 		if (aspath_get_last_as(attr->aspath) == bgp->as)
 			do_loop_check = 0;
 
-	if (CHECK_FLAG(peer->af_flags[afi][safi], PEER_FLAG_REFLECTOR_CLIENT))
+	/* When using bgp ipv4 labeled session, the local prefix is
+	 * received by a peer, and finds out that the proposed prefix
+	 * and its next-hop are the same. To avoid a route loop locally,
+	 * no nexthop entry is referenced for that prefix, and the route
+	 * will not be selected.
+	 *
+	 * As it has been done for ipv4-unicast, apply the following fix
+	 * for labeled address families: when the received peer is
+	 * a route reflector, the prefix has to be selected, even if the
+	 * route can not be installed locally.
+	 */
+	if (CHECK_FLAG(peer->af_flags[afi][safi], PEER_FLAG_REFLECTOR_CLIENT) ||
+	    (safi == SAFI_UNICAST && !peer->afc[afi][safi] &&
+	     peer->afc[afi][SAFI_LABELED_UNICAST] &&
+	     CHECK_FLAG(peer->af_flags[afi][SAFI_LABELED_UNICAST],
+			PEER_FLAG_REFLECTOR_CLIENT)))
 		bgp_nht_param_prefix = NULL;
 	else
 		bgp_nht_param_prefix = p;

doc/user/zebra.rst

@@ -815,6 +815,16 @@ Allocated label chunks table can be dumped using the command
    range is configured, static label requests that match that
    range are not accepted.
 
+FEC nexthop entry resolution over MPLS networks
+-----------------------------------------------
+
+The LSP associated with a BGP labeled route is normally restricted to
+directly-connected nexthops. If connected nexthops are not available,
+the LSP entry will not be installed. This command permits the use of
+recursive resolution for LSPs, similar to that available for IP routes.
+
+.. clicmd:: mpls fec nexthop-resolution
+
 .. _zebra-srv6:
 
 Segment-Routing IPv6

lib/nexthop.c

@@ -713,6 +713,15 @@ struct nexthop *nexthop_next(const struct nexthop *nexthop)
 	return NULL;
 }
 
+struct nexthop *nexthop_next_resolution(const struct nexthop *nexthop,
+					bool nexthop_resolution)
+{
+	if (nexthop_resolution)
+		return nexthop_next(nexthop);
+	/* no resolution attempt */
+	return nexthop->next;
+}
+
 /* Return the next nexthop in the tree that is resolved and active */
 struct nexthop *nexthop_next_active_resolved(const struct nexthop *nexthop)
 {

lib/nexthop.h

@@ -225,6 +225,8 @@ extern bool nexthop_labels_match(const struct nexthop *nh1,
 extern const char *nexthop2str(const struct nexthop *nexthop,
 			       char *str, int size);
 extern struct nexthop *nexthop_next(const struct nexthop *nexthop);
+extern struct nexthop *nexthop_next_resolution(const struct nexthop *nexthop,
+					       bool nexthop_resolution);
 extern struct nexthop *
 nexthop_next_active_resolved(const struct nexthop *nexthop);
 extern unsigned int nexthop_level(const struct nexthop *nexthop);

tests/topotests/zebra_fec_nexthop_resolution/r1/bgpd.conf

@@ -0,0 +1,24 @@
+!
+router bgp 65500
+ bgp router-id 192.0.2.1
+ neighbor 192.0.2.3 remote-as 65500
+ neighbor 192.0.2.3 update-source lo
+ neighbor 192.0.2.7 remote-as 65500
+ neighbor 192.0.2.7 ttl-security hops 10
+ neighbor 192.0.2.7 disable-connected-check
+ neighbor 192.0.2.7 update-source lo
+ !
+ address-family ipv4 unicast
+  network 192.0.2.1/32
+  no neighbor 192.0.2.3 activate
+  neighbor 192.0.2.7 activate
+ exit-address-family
+ !
+ address-family ipv4 labeled-unicast
+  neighbor 192.0.2.3 activate
+  neighbor 192.0.2.3 route-reflector-client
+  neighbor 192.0.2.3 next-hop-self force
+ exit-address-family
+ !
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r1/ospfd.conf.after

@@ -0,0 +1,25 @@
+log stdout
+!
+interface lo
+ ip ospf passive
+exit
+!
+interface r1-eth0
+ ip ospf network point-to-point
+ ip ospf hello-interval 1
+exit
+!
+router ospf
+ ospf router-id 192.0.2.1
+ network 192.0.2.1/32 area 0.0.0.0
+ network 192.168.1.0/24 area 0.0.0.0
+ passive-interface lo
+ capability opaque
+ mpls-te on
+ mpls-te router-address 192.0.2.1
+ segment-routing on
+ segment-routing global-block 1000 10000 local-block 32000 32999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.1/32 index 11
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r1/zebra.conf

@@ -0,0 +1,13 @@
+interface lo
+ ip address 192.0.2.1/32
+ mpls enable
+exit
+!
+interface r1-eth0
+ ip address 192.168.1.1/24
+ mpls enable
+ link-params
+  enable
+  exit-link-params
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r2/bgpd.conf

@@ -0,0 +1,23 @@
+router bgp 65500
+ bgp router-id 192.0.2.2
+ neighbor 192.0.2.1 remote-as 65500
+ neighbor 192.0.2.1 update-source lo
+ neighbor 192.0.2.3 remote-as 65500
+ neighbor 192.0.2.3 update-source lo
+ !
+ address-family ipv4 unicast
+  network 192.0.2.2/32
+  no neighbor 192.0.2.1 activate
+  no neighbor 192.0.2.3 activate
+ exit-address-family
+ !
+ address-family ipv4 labeled-unicast
+  neighbor 192.0.2.1 activate
+  neighbor 192.0.2.1 route-reflector-client
+  neighbor 192.0.2.1 next-hop-self force
+  neighbor 192.0.2.3 activate
+  neighbor 192.0.2.3 route-reflector-client
+  neighbor 192.0.2.3 next-hop-self force
+ exit-address-family
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r2/isisd.conf

@@ -0,0 +1,25 @@
+!
+interface lo
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+interface r2-eth1
+ ip router isis 2
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+router isis 1
+ is-type level-1
+ net 49.0000.0007.e901.2223.00
+ lsp-timers gen-interval 1 refresh-interval 900 max-lifetime 1200
+ mpls-te on
+ mpls-te router-address 192.0.2.2
+ segment-routing on
+ segment-routing global-block 11000 20000 local-block 36000 36999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.2/32 index 22 no-php-flag
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r2/ospfd.conf.after

@@ -0,0 +1,32 @@
+log stdout
+!
+interface lo
+ ip ospf network point-to-point
+ ip ospf passive
+exit
+!
+interface r2-eth0
+ ip ospf network point-to-point
+ ip ospf hello-interval 1
+exit
+!
+interface r2-eth1
+ ip ospf network point-to-point
+ ip ospf hello-interval 1
+exit
+!
+router ospf
+ ospf router-id 192.0.2.2
+ network 192.0.2.2/32 area 0.0.0.0
+ network 192.168.1.0/24 area 0.0.0.0
+ network 192.168.2.0/24 area 0.0.0.0
+ passive-interface lo
+ capability opaque
+ mpls-te on
+ mpls-te router-address 192.0.2.2
+ segment-routing on
+ segment-routing global-block 1000 10000 local-block 36000 36999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.2/32 index 22
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r2/zebra.conf

@@ -0,0 +1,16 @@
+!
+interface lo
+ ip address 192.0.2.2/32
+ mpls enable
+exit
+!
+interface r2-eth0
+ ip address 192.168.1.2/24
+ mpls enable
+exit
+!
+interface r2-eth1
+ ip address 192.168.2.2/24
+ mpls enable
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r3/bgpd.conf

@@ -0,0 +1,23 @@
+router bgp 65500
+ bgp router-id 192.0.2.3
+ neighbor 192.0.2.1 remote-as 65500
+ neighbor 192.0.2.1 update-source lo
+ neighbor 192.0.2.5 remote-as 65500
+ neighbor 192.0.2.5 update-source lo
+ !
+ address-family ipv4 unicast
+  network 192.0.2.3/32
+  no neighbor 192.0.2.1 activate
+  no neighbor 192.0.2.5 activate
+ exit-address-family
+ !
+ address-family ipv4 labeled-unicast
+  neighbor 192.0.2.1 activate
+  neighbor 192.0.2.1 route-reflector-client
+  neighbor 192.0.2.1 next-hop-self force
+  neighbor 192.0.2.5 activate
+  neighbor 192.0.2.5 route-reflector-client
+  neighbor 192.0.2.5 next-hop-self force
+ exit-address-family
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r3/isisd.conf

@@ -0,0 +1,25 @@
+!
+interface lo
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+interface r3-eth1
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+router isis 1
+ is-type level-1
+ net 49.0000.0007.e901.3333.00
+ lsp-timers gen-interval 1 refresh-interval 900 max-lifetime 1200
+ mpls-te on
+ mpls-te router-address 192.0.2.3
+ segment-routing on
+ segment-routing global-block 11000 12000 local-block 36000 36999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.3/32 index 33
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r3/ospfd.conf.after

@@ -0,0 +1,26 @@
+log stdout
+!
+interface lo
+ ip ospf network point-to-point
+ ip ospf passive
+exit
+!
+interface r3-eth0
+ ip ospf network point-to-point
+ ip ospf hello-interval 1
+exit
+!
+router ospf
+ ospf router-id 192.0.2.3
+ network 192.0.2.3/32 area 0.0.0.0
+ network 192.168.2.0/24 area 0.0.0.0
+ passive-interface lo
+ capability opaque
+ mpls-te on
+ mpls-te router-address 192.0.2.3
+ segment-routing on
+ segment-routing global-block 1000 10000 local-block 30000 30999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.3/32 index 33
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r3/zebra.conf

@@ -0,0 +1,19 @@
+!
+interface lo
+ ip address 192.0.2.3/32
+ mpls enable
+exit
+!
+interface r3-eth0
+ ip address 192.168.2.3/24
+ mpls enable
+ link-params
+  enable
+  exit-link-params
+exit
+!
+interface r3-eth1
+ ip address 192.168.3.3/24
+ mpls enable
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r4/bgpd.conf

@@ -0,0 +1,24 @@
+!
+router bgp 65500
+ bgp router-id 192.0.2.4
+ neighbor 192.0.2.1 remote-as 65500
+ neighbor 192.0.2.1 ttl-security hops 10
+ neighbor 192.0.2.1 disable-connected-check
+ neighbor 192.0.2.1 update-source lo
+ neighbor 192.0.2.3 remote-as 65500
+ neighbor 192.0.2.3 update-source lo
+ !
+ address-family ipv4 unicast
+  network 192.0.2.4/32
+  neighbor 192.0.2.1 activate
+  no neighbor 192.0.2.3 activate
+ exit-address-family
+ !
+ address-family ipv4 labeled-unicast
+  neighbor 192.0.2.3 activate
+  neighbor 192.0.2.3 route-reflector-client
+  neighbor 192.0.2.3 next-hop-self force
+ exit-address-family
+ !
+exit
+!

tests/topotests/zebra_fec_nexthop_resolution/r4/isisd.conf

@@ -0,0 +1,31 @@
+!
+interface lo
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+interface r4-eth0
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+interface r4-eth1
+ ip router isis 1
+ isis hello-interval 1
+ isis hello-multiplier 3
+exit
+!
+router isis 1
+ is-type level-1
+ net 49.0000.0007.e901.4444.00
+ lsp-timers gen-interval 1 refresh-interval 900 max-lifetime 1200
+ mpls-te on
+ mpls-te router-address 192.0.2.4
+ segment-routing on
+ segment-routing global-block 11000 12000 local-block 37000 37999
+ segment-routing node-msd 8
+ segment-routing prefix 192.0.2.4/32 index 44
+exit
+!