From 4e76df05476e728d3bdd53821c0f20e4139db1f8 Mon Sep 17 00:00:00 2001
From: Philippe Guibert <philippe.guibert@6wind.com>
Date: Fri, 22 Dec 2023 11:35:09 +0100
Subject: [PATCH] isis, lib: add isis srv6 end sid to ls_prefix

According to draft-ietf-lsr-isis-srv6-extensions draft,
the End SID should be available in link state prefix
information.

Add the SID information in the link state prefix, by
getting the END SID from the locator TLV information.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
---
 isisd/isis_lsp.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 isisd/isis_lsp.h |  2 ++
 isisd/isis_te.c  | 45 +++++++++++++++++++++++++++++++++++++++++--
 isisd/isis_te.h  |  1 +
 lib/link_state.c | 36 +++++++++++++++++++++++++++++++++-
 lib/link_state.h |  6 ++++++
 6 files changed, 137 insertions(+), 3 deletions(-)

diff --git a/isisd/isis_lsp.c b/isisd/isis_lsp.c
index bda7ed89a4c2..391d42fba156 100644
--- a/isisd/isis_lsp.c
+++ b/isisd/isis_lsp.c
@@ -2340,6 +2340,56 @@ static int lsp_handle_adj_state_change(struct isis_adjacency *adj)
 	return 0;
 }
 
+/*
+ * Iterate over all SRv6 locator TLVs
+ */
+int isis_lsp_iterate_srv6_locator(struct isis_lsp *lsp, uint16_t mtid,
+				  lsp_ip_reach_iter_cb cb, void *arg)
+{
+	bool pseudo_lsp = LSP_PSEUDO_ID(lsp->hdr.lsp_id);
+	struct isis_lsp *frag;
+	struct listnode *node;
+
+	if (lsp->hdr.seqno == 0 || lsp->hdr.rem_lifetime == 0)
+		return LSP_ITER_CONTINUE;
+
+	/* Parse LSP */
+	if (lsp->tlvs) {
+		if (!pseudo_lsp) {
+			struct isis_item_list *srv6_locator_reachs;
+			struct isis_srv6_locator_tlv *r;
+
+			srv6_locator_reachs =
+				isis_lookup_mt_items(&lsp->tlvs->srv6_locator,
+						     mtid);
+
+			for (r = srv6_locator_reachs
+					 ? (struct isis_srv6_locator_tlv *)
+						   srv6_locator_reachs->head
+					 : NULL;
+			     r; r = r->next) {
+				if ((*cb)((struct prefix *)&r->prefix,
+					  r->metric, false /* ignore */,
+					  r->subtlvs, arg) == LSP_ITER_STOP)
+					return LSP_ITER_STOP;
+			}
+		}
+	}
+
+	/* Parse LSP fragments if it is not a fragment itself */
+	if (!LSP_FRAGMENT(lsp->hdr.lsp_id))
+		for (ALL_LIST_ELEMENTS_RO(lsp->lspu.frags, node, frag)) {
+			if (!frag->tlvs)
+				continue;
+
+			if (isis_lsp_iterate_srv6_locator(frag, mtid, cb,
+							  arg) == LSP_ITER_STOP)
+				return LSP_ITER_STOP;
+		}
+
+	return LSP_ITER_CONTINUE;
+}
+
 /*
  * Iterate over all IP reachability TLVs in a LSP (all fragments) of the given
  * address-family and MT-ID.
diff --git a/isisd/isis_lsp.h b/isisd/isis_lsp.h
index 3839a9504c05..15db88b02f36 100644
--- a/isisd/isis_lsp.h
+++ b/isisd/isis_lsp.h
@@ -143,6 +143,8 @@ int isis_lsp_iterate_ip_reach(struct isis_lsp *lsp, int family, uint16_t mtid,
 			      lsp_ip_reach_iter_cb cb, void *arg);
 int isis_lsp_iterate_is_reach(struct isis_lsp *lsp, uint16_t mtid,
 			      lsp_is_reach_iter_cb cb, void *arg);
+int isis_lsp_iterate_srv6_locator(struct isis_lsp *lsp, uint16_t mtid,
+				  lsp_ip_reach_iter_cb cb, void *arg);
 
 #define lsp_flood(lsp, circuit) \
 	_lsp_flood((lsp), (circuit), __func__, __FILE__, __LINE__)
diff --git a/isisd/isis_te.c b/isisd/isis_te.c
index 3683f7455821..bb73a4425774 100644
--- a/isisd/isis_te.c
+++ b/isisd/isis_te.c
@@ -1258,8 +1258,11 @@ static int lsp_to_subnet_cb(const struct prefix *prefix, uint32_t metric,
 	if (!args || !prefix)
 		return LSP_ITER_CONTINUE;
 
-	te_debug("  |- Process Extended %s Reachability %pFX",
-		 prefix->family == AF_INET ? "IP" : "IPv6", prefix);
+	if (args->srv6_locator)
+		te_debug("  |- Process SRv6 Locator %pFX", prefix);
+	else
+		te_debug("  |- Process Extended %s Reachability %pFX",
+			 prefix->family == AF_INET ? "IP" : "IPv6", prefix);
 
 	vertex = args->vertex;
 
@@ -1386,6 +1389,38 @@ static int lsp_to_subnet_cb(const struct prefix *prefix, uint32_t metric,
 		}
 	}
 
+	/* Update SRv6 SID and locator if any */
+	if (subtlvs && subtlvs->srv6_end_sids.count != 0) {
+		struct isis_srv6_end_sid_subtlv *psid;
+		struct ls_srv6_sid sr = {};
+
+		psid = (struct isis_srv6_end_sid_subtlv *)
+			       subtlvs->srv6_end_sids.head;
+		sr.behavior = psid->behavior;
+		sr.flags = psid->flags;
+		memcpy(&sr.sid, &psid->sid, sizeof(struct in6_addr));
+
+		if (!CHECK_FLAG(ls_pref->flags, LS_PREF_SRV6) ||
+		    memcmp(&ls_pref->srv6, &sr, sizeof(struct ls_srv6_sid))) {
+			memcpy(&ls_pref->srv6, &sr, sizeof(struct ls_srv6_sid));
+			SET_FLAG(ls_pref->flags, LS_PREF_SRV6);
+			if (subnet->status != NEW)
+				subnet->status = UPDATE;
+		} else {
+			if (subnet->status == ORPHAN)
+				subnet->status = SYNC;
+		}
+	} else {
+		if (CHECK_FLAG(ls_pref->flags, LS_PREF_SRV6)) {
+			UNSET_FLAG(ls_pref->flags, LS_PREF_SRV6);
+			if (subnet->status != NEW)
+				subnet->status = UPDATE;
+		} else {
+			if (subnet->status == ORPHAN)
+				subnet->status = SYNC;
+		}
+	}
+
 	/* Update status and Export Link State Edge if needed */
 	if (subnet->status != SYNC) {
 		if (args->export)
@@ -1454,12 +1489,18 @@ static void isis_te_parse_lsp(struct mpls_te_area *mta, struct isis_lsp *lsp)
 				  &args);
 
 	/* Process all Extended IP (v4 & v6) in LSP (all fragments) */
+	args.srv6_locator = false;
 	isis_lsp_iterate_ip_reach(lsp, AF_INET, ISIS_MT_IPV4_UNICAST,
 				  lsp_to_subnet_cb, &args);
 	isis_lsp_iterate_ip_reach(lsp, AF_INET6, ISIS_MT_IPV6_UNICAST,
 				  lsp_to_subnet_cb, &args);
 	isis_lsp_iterate_ip_reach(lsp, AF_INET6, ISIS_MT_IPV4_UNICAST,
 				  lsp_to_subnet_cb, &args);
+	args.srv6_locator = true;
+	isis_lsp_iterate_srv6_locator(lsp, ISIS_MT_STANDARD, lsp_to_subnet_cb,
+				      &args);
+	isis_lsp_iterate_srv6_locator(lsp, ISIS_MT_IPV6_UNICAST,
+				      lsp_to_subnet_cb, &args);
 
 	/* Clean remaining Orphan Edges or Subnets */
 	if (IS_EXPORT_TE(mta))
diff --git a/isisd/isis_te.h b/isisd/isis_te.h
index bf1dc2b9bbbd..532a24e7e406 100644
--- a/isisd/isis_te.h
+++ b/isisd/isis_te.h
@@ -103,6 +103,7 @@ struct isis_te_args {
 	struct ls_ted *ted;
 	struct ls_vertex *vertex;
 	bool export;
+	bool srv6_locator;
 };
 
 enum lsp_event { LSP_UNKNOWN, LSP_ADD, LSP_UPD, LSP_DEL, LSP_INC, LSP_TICK };
diff --git a/lib/link_state.c b/lib/link_state.c
index c758b7f57517..3d96c75f6d1e 100644
--- a/lib/link_state.c
+++ b/lib/link_state.c
@@ -414,6 +414,13 @@ int ls_prefix_same(struct ls_prefix *p1, struct ls_prefix *p2)
 		    || (p1->sr.sid_flag != p2->sr.sid_flag))
 			return 0;
 	}
+	if (CHECK_FLAG(p1->flags, LS_PREF_SRV6)) {
+		if (memcmp(&p1->srv6.sid, &p2->srv6.sid,
+			   sizeof(struct in6_addr)) ||
+		    (p1->srv6.flags != p2->srv6.flags) ||
+		    (p1->srv6.behavior != p2->srv6.behavior))
+			return 0;
+	}
 
 	/* OK, p1 & p2 are equal */
 	return 1;
@@ -1388,6 +1395,11 @@ static struct ls_prefix *ls_parse_prefix(struct stream *s)
 		STREAM_GETC(s, ls_pref->sr.sid_flag);
 		STREAM_GETC(s, ls_pref->sr.algo);
 	}
+	if (CHECK_FLAG(ls_pref->flags, LS_PREF_SRV6)) {
+		STREAM_GET(&ls_pref->srv6.sid, s, sizeof(struct in6_addr));
+		STREAM_GETW(s, ls_pref->srv6.behavior);
+		STREAM_GETC(s, ls_pref->srv6.flags);
+	}
 
 	return ls_pref;
 
@@ -1632,6 +1644,11 @@ static int ls_format_prefix(struct stream *s, struct ls_prefix *ls_pref)
 		stream_putc(s, ls_pref->sr.sid_flag);
 		stream_putc(s, ls_pref->sr.algo);
 	}
+	if (CHECK_FLAG(ls_pref->flags, LS_PREF_SRV6)) {
+		stream_put(s, &ls_pref->srv6.sid, sizeof(struct in6_addr));
+		stream_putw(s, ls_pref->srv6.behavior);
+		stream_putc(s, ls_pref->srv6.flags);
+	}
 
 	return 0;
 }
@@ -2748,6 +2765,13 @@ static void ls_show_subnet_vty(struct ls_subnet *subnet, struct vty *vty,
 		sbuf_push(&sbuf, 4, "SID: %d\tAlgorithm: %d\tFlags: 0x%x\n",
 			  pref->sr.sid, pref->sr.algo, pref->sr.sid_flag);
 
+	if (CHECK_FLAG(pref->flags, LS_PREF_SRV6))
+		sbuf_push(&sbuf, 4,
+			  "SIDv6: %pI6\tEndpoint behavior: %s\tFlags: 0x%x\n",
+			  &pref->srv6.sid,
+			  seg6local_action2str(pref->srv6.behavior),
+			  pref->srv6.flags);
+
 end:
 	vty_out(vty, "%s\n", sbuf_buf(&sbuf));
 	sbuf_free(&sbuf);
@@ -2757,7 +2781,7 @@ static void ls_show_subnet_json(struct ls_subnet *subnet,
 				struct json_object *json)
 {
 	struct ls_prefix *pref;
-	json_object *jsr;
+	json_object *jsr, *jsrv6;
 	char buf[INET6_BUFSIZ];
 
 	pref = subnet->ls_pref;
@@ -2787,6 +2811,16 @@ static void ls_show_subnet_json(struct ls_subnet *subnet,
 		snprintfrr(buf, INET6_BUFSIZ, "0x%x", pref->sr.sid_flag);
 		json_object_string_add(jsr, "flags", buf);
 	}
+	if (CHECK_FLAG(pref->flags, LS_PREF_SRV6)) {
+		jsrv6 = json_object_new_object();
+		json_object_object_add(json, "segment-routing-ipv6", jsrv6);
+		snprintfrr(buf, INET6_BUFSIZ, "%pI6", &pref->srv6.sid);
+		json_object_string_add(jsrv6, "sid", buf);
+		json_object_string_add(jsrv6, "behavior",
+				       seg6local_action2str(pref->srv6.behavior));
+		snprintfrr(buf, INET6_BUFSIZ, "0x%x", pref->srv6.flags);
+		json_object_string_add(jsrv6, "flags", buf);
+	}
 }
 
 void ls_show_subnet(struct ls_subnet *subnet, struct vty *vty,
diff --git a/lib/link_state.h b/lib/link_state.h
index d819c20db763..c54e2ec6d904 100644
--- a/lib/link_state.h
+++ b/lib/link_state.h
@@ -243,6 +243,7 @@ struct ls_attributes {
 #define LS_PREF_EXTENDED_TAG	0x04
 #define LS_PREF_METRIC		0x08
 #define LS_PREF_SR		0x10
+#define LS_PREF_SRV6		0x20
 
 /* Link State Prefix */
 struct ls_prefix {
@@ -258,6 +259,11 @@ struct ls_prefix {
 		uint8_t sid_flag;	/* Segment Routing Flags */
 		uint8_t algo;		/* Algorithm for Segment Routing */
 	} sr;
+	struct ls_srv6_sid {
+		struct in6_addr sid; /* Segment Routing ID */
+		uint16_t behavior;   /* Endpoint behavior bound to the SID */
+		uint8_t flags;	     /* Flags */
+	} srv6;
 };
 
 /**