isisd: add support for segment routing

This is an implementation of the IS-IS SR draft [1] for FRR.

The following features are supported:
* IPv4 and IPv6 Prefix-SIDs;
* IPv4 and IPv6 Adj-SIDs and LAN-Adj-SIDs;
* Index and absolute labels;
* The no-php and explicit-null Prefix-SID flags;
* Full integration with the Label Manager.

Known limitations:
* No support for Anycast-SIDs;
* No support for the SID/Label Binding TLV (required for LDP interop).
* No support for persistent Adj-SIDs;
* No support for multiple SRGBs.

[1] draft-ietf-isis-segment-routing-extensions-25

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/isisd/isis_adjacency.h b/isisd/isis_adjacency.h
index 834eba7925..ec17446ade 100644
--- a/isisd/isis_adjacency.h
+++ b/isisd/isis_adjacency.h
@@ -69,6 +69,7 @@ struct isis_dis_record {
 };
 
 struct bfd_session;
+struct isis_area;
 
 struct isis_adjacency {
 	uint8_t snpa[ETH_ALEN];		    /* NeighbourSNPAAddress */
@@ -103,6 +104,7 @@ struct isis_adjacency {
 	uint16_t *mt_set;      /* Topologies this adjacency is valid for */
 	unsigned int mt_count; /* Number of entries in mt_set */
 	struct bfd_session *bfd_session;
+	struct list *adj_sids; /* Segment Routing Adj-SIDs. */
 };
 
 struct isis_threeway_adj;
@@ -111,6 +113,8 @@ struct isis_adjacency *isis_adj_lookup(const uint8_t *sysid,
 				       struct list *adjdb);
 struct isis_adjacency *isis_adj_lookup_snpa(const uint8_t *ssnpa,
 					    struct list *adjdb);
+bool isis_adj_exists(const struct isis_area *area, int level,
+		     const uint8_t *sysid);
 struct isis_adjacency *isis_new_adj(const uint8_t *id, const uint8_t *snpa,
 				    int level, struct isis_circuit *circuit);
 void isis_delete_adj(void *adj);