lib, zebra: Add SR-TE policy infrastructure to zebra

For the sake of Segment Routing (SR) and Traffic Engineering (TE)
Policies there's a need for additional infrastructure within zebra.
The infrastructure in this PR is supposed to manage such policies
in terms of installing binding SIDs and LSPs. Also it is capable of
managing MPLS labels using the label manager, keeping track of
nexthops (for resolving labels) and notifying interested parties about
changes of a policy/LSP state. Further it enables a route map mechanism
for BGP and SR-TE colors such that learned BGP routes can be mapped
onto SR-TE Policies.

This PR does not introduce any usable features by now, it is just
infrastructure for other upcoming PRs which will introduce 'pathd',
a new SR-TE daemon.

Co-authored-by: Renato Westphal <renato@opensourcerouting.org>
Co-authored-by: GalaxyGorilla <sascha@netdef.org>
Signed-off-by: Sebastien Merle <sebastien@netdef.org>

1 files changed, 22 insertions, 10 deletions

diff --git a/zebra/zebra_rnh.c b/zebra/zebra_rnh.c
index b151e90a9..cdc00f602 100644
--- a/zebra/zebra_rnh.c
+++ b/zebra/zebra_rnh.c
@@ -46,6 +46,7 @@
 #include "zebra/debug.h"
 #include "zebra/zebra_rnh.h"
 #include "zebra/zebra_routemap.h"
+#include "zebra/zebra_srte.h"
 #include "zebra/interface.h"
 #include "zebra/zebra_memory.h"
 #include "zebra/zebra_errors.h"
@@ -57,8 +58,6 @@ static void free_state(vrf_id_t vrf_id, struct route_entry *re,
 static void copy_state(struct rnh *rnh, const struct route_entry *re,
 		       struct route_node *rn);
 static int compare_state(struct route_entry *r1, struct route_entry *r2);
-static int send_client(struct rnh *rnh, struct zserv *client,
-		       enum rnh_type type, vrf_id_t vrf_id);
 static void print_rnh(struct route_node *rn, struct vty *vty);
 static int zebra_client_cleanup_rnh(struct zserv *client);
 
@@ -305,7 +304,7 @@ void zebra_add_rnh_client(struct rnh *rnh, struct zserv *client,
 	 * We always need to respond with known information,
 	 * currently multiple daemons expect this behavior
 	 */
-	send_client(rnh, client, type, vrf_id);
+	zebra_send_rnh_update(rnh, client, type, vrf_id, 0);
 }
 
 void zebra_remove_rnh_client(struct rnh *rnh, struct zserv *client,
@@ -531,8 +530,9 @@ static void zebra_rnh_eval_import_check_entry(struct zebra_vrf *zvrf, afi_t afi,
 		}
 		/* state changed, notify clients */
 		for (ALL_LIST_ELEMENTS_RO(rnh->client_list, node, client)) {
-			send_client(rnh, client,
-				    RNH_IMPORT_CHECK_TYPE, zvrf->vrf->vrf_id);
+			zebra_send_rnh_update(rnh, client,
+					      RNH_IMPORT_CHECK_TYPE,
+					      zvrf->vrf->vrf_id, 0);
 		}
 	}
 }
@@ -594,7 +594,8 @@ static void zebra_rnh_notify_protocol_clients(struct zebra_vrf *zvrf, afi_t afi,
 					zebra_route_string(client->proto));
 		}
 
-		send_client(rnh, client, RNH_NEXTHOP_TYPE, zvrf->vrf->vrf_id);
+		zebra_send_rnh_update(rnh, client, RNH_NEXTHOP_TYPE,
+				      zvrf->vrf->vrf_id, 0);
 	}
 
 	if (re)
@@ -1107,8 +1108,9 @@ static int compare_state(struct route_entry *r1, struct route_entry *r2)
 	return 0;
 }
 
-static int send_client(struct rnh *rnh, struct zserv *client,
-		       enum rnh_type type, vrf_id_t vrf_id)
+int zebra_send_rnh_update(struct rnh *rnh, struct zserv *client,
+			  enum rnh_type type, vrf_id_t vrf_id,
+			  uint32_t srte_color)
 {
 	struct stream *s = NULL;
 	struct route_entry *re;
@@ -1117,6 +1119,7 @@ static int send_client(struct rnh *rnh, struct zserv *client,
 	struct nexthop *nh;
 	struct route_node *rn;
 	int ret;
+	uint32_t message = 0;
 	int cmd = (type == RNH_IMPORT_CHECK_TYPE) ? ZEBRA_IMPORT_CHECK_UPDATE
 						  : ZEBRA_NEXTHOP_UPDATE;
 
@@ -1128,6 +1131,11 @@ static int send_client(struct rnh *rnh, struct zserv *client,
 
 	zclient_create_header(s, cmd, vrf_id);
 
+	/* Message flags. */
+	if (srte_color)
+		SET_FLAG(message, ZAPI_MESSAGE_SRTE);
+	stream_putl(s, message);
+
 	stream_putw(s, rn->p.family);
 	switch (rn->p.family) {
 	case AF_INET:
@@ -1144,6 +1152,9 @@ static int send_client(struct rnh *rnh, struct zserv *client,
 			 __func__, rn->p.family);
 		goto failure;
 	}
+	if (srte_color)
+		stream_putl(s, srte_color);
+
 	if (re) {
 		struct zapi_nexthop znh;
 		struct nexthop_group *nhg;
@@ -1160,7 +1171,7 @@ static int send_client(struct rnh *rnh, struct zserv *client,
 		for (ALL_NEXTHOPS_PTR(nhg, nh))
 			if (rnh_nexthop_valid(re, nh)) {
 				zapi_nexthop_from_nexthop(&znh, nh);
-				ret = zapi_nexthop_encode(s, &znh, 0/*flags*/);
+				ret = zapi_nexthop_encode(s, &znh, 0, message);
 				if (ret < 0)
 					goto failure;
 
@@ -1173,7 +1184,8 @@ static int send_client(struct rnh *rnh, struct zserv *client,
 				if (rnh_nexthop_valid(re, nh)) {
 					zapi_nexthop_from_nexthop(&znh, nh);
 					ret = zapi_nexthop_encode(
-						s, &znh, 0 /* flags */);
+						s, &znh, 0 /* flags */,
+						0 /* message */);
 					if (ret < 0)
 						goto failure;