BGP: Add options to require BGP capabilities

Some BGP capabilities change the BGP behavior in a significant way, so if
the configuration depends on it, it is better to not establish BGP
session when the capability is not available.

Add several BGP option to require individual BGP capabilities during
session negotiation.

1 files changed, 10 insertions, 0 deletions

diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index 2e95037c..61127562 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -138,6 +138,13 @@ struct bgp_config {
   const char *dynamic_name;		/* Name pattern for dynamic BGP */
   int dynamic_name_digits;		/* Minimum number of digits for dynamic names */
   int check_link;			/* Use iface link state for liveness detection */
+  int require_refresh;			/* Require remote support for route refresh [RFC 2918] */
+  int require_enhanced_refresh;		/* Require remote support for enhanced route refresh [RFC 7313] */
+  int require_as4;			/* Require remote support for 4B AS numbers [RFC 6793] */
+  int require_extended_messages;	/* Require remote support for extended messages [RFC 8654] */
+  int require_hostname;			/* Require remote support for hostname [draft] */
+  int require_gr;			/* Require remote support for graceful restart [RFC 4724] */
+  int require_llgr;			/* Require remote support for long-lived graceful restart [draft] */
   struct bfd_options *bfd;		/* Use BFD for liveness detection */
 };
 
@@ -159,7 +166,9 @@ struct bgp_channel_config {
   u8 llgr_able;				/* Allow full long-lived GR for the channel */
   uint llgr_time;			/* Long-lived graceful restart stale time */
   u8 ext_next_hop;			/* Allow both IPv4 and IPv6 next hops */
+  u8 require_ext_next_hop;		/* Require remote support of IPv4 NLRI with IPv6 next hops [RFC 8950] */
   u8 add_path;				/* Use ADD-PATH extension [RFC 7911] */
+  u8 require_add_path;			/* Require remote support of ADD-PATH extension [RFC 7911] */
   u8 aigp;				/* AIGP is allowed on this session */
   u8 aigp_originate;			/* AIGP is originated automatically */
   u32 cost;				/* IGP cost for direct next hops */
@@ -657,6 +666,7 @@ bgp_total_aigp_metric(rte *r)
 
 void bgp_dump_state_change(struct bgp_conn *conn, uint old, uint new);
 void bgp_prepare_capabilities(struct bgp_conn *conn);
+int bgp_check_capabilities(struct bgp_conn *conn);
 const struct bgp_af_desc *bgp_get_af_desc(u32 afi);
 const struct bgp_af_caps *bgp_find_af_caps(struct bgp_caps *caps, u32 afi);
 void bgp_schedule_packet(struct bgp_conn *conn, struct bgp_channel *c, int type);