BGP: Implement BGP roles

Implement BGP roles as described in RFC 9234. It is  a mechanism for
route leak prevention and automatic route filtering based on common BGP
topology relationships. It defines role capability (controlled by 'local
role' option) and OTC route attribute, which is used for automatic route
filtering and leak detection.

Minor changes done by commiter.

1 files changed, 19 insertions, 0 deletions

diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index 89507f1a..3b28a338 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -102,6 +102,7 @@
  * RFC 8212 - Default EBGP Route Propagation Behavior without Policies
  * RFC 8654 - Extended Message Support for BGP
  * RFC 9117 - Revised Validation Procedure for BGP Flow Specifications
+ * RFC 9234 - Route Leak Prevention and Detection Using Roles
  * draft-ietf-idr-ext-opt-param-07
  * draft-uttaro-idr-bgp-persistence-04
  * draft-walton-bgp-hostname-capability-02
@@ -1983,6 +1984,12 @@ bgp_postconfig(struct proto_config *CF)
   if (internal && cf->rs_client)
     cf_error("Only external neighbor can be RS client");
 
+  if (internal && (cf->local_role != BGP_ROLE_UNDEFINED))
+    cf_error("Local role cannot be set on IBGP sessions");
+
+  if (cf->require_roles && (cf->local_role == BGP_ROLE_UNDEFINED))
+    cf_error("Local role must be set if roles are required");
+
   if (!cf->confederation && cf->confederation_member)
     cf_error("Confederation ID must be set for member sessions");
 
@@ -2345,6 +2352,15 @@ bgp_show_afis(int code, char *s, u32 *afis, uint count)
   cli_msg(code, b.start);
 }
 
+static const char *
+bgp_format_role_name(u8 role)
+{
+  static const char *bgp_role_names[] = { "provider", "rs_server", "rs_client", "customer", "peer" };
+  if (role == BGP_ROLE_UNDEFINED) return "undefined";
+  if (role < 5) return bgp_role_names[role];
+  return "?";
+}
+
 static void
 bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps)
 {
@@ -2473,6 +2489,9 @@ bgp_show_capabilities(struct bgp_proto *p UNUSED, struct bgp_caps *caps)
 
   if (caps->hostname)
     cli_msg(-1006, "      Hostname: %s", caps->hostname);
+
+  if (caps->role != BGP_ROLE_UNDEFINED)
+    cli_msg(-1006, "      Role: %s", bgp_format_role_name(caps->role));
 }
 
 static void