isisd: fix sending remote interface ip address after enabling MPLS TE

If MPLS TE is enabled, the router encodes the local and remote interface
IP address in the "Extended Reachability" TLV.

> east-vm(config)# do show isis database detail east-vm.00-00
>  Extended Reachability: 0007.e901.3333.00 (Metric: 10)
>    Local Interface IP Address(es): 10.126.0.2
>    Remote Interface IP Address(es): 10.126.0.3
>    Maximum Bandwidth: 1.76258e+08 (Bytes/sec)

The remote interface is added when the circuit adjacency comes up after
setting MPLS TE. However, if MPLS TE is enabled after, the remote
address is not added. It happens after disabling and re-enabling the
MPLS TE.

> east-vm(config)# router isis 1
> east-vm(config-router)# no mpls on
> east-vm(config-router)# mpls on
> east-vm(config)# do show isis database detail east-vm.00-00
>  Extended Reachability: 0007.e901.3333.00 (Metric: 10)
>    Local Interface IP Address(es): 10.126.0.2
>    Maximum Bandwidth: 1.76258e+08 (Bytes/sec)

Update the remote IPv4 and IPv6 of all adjacencies after enabling MPLS
TE.

Fixes: 1b3f47d04c ("isisd: Update TLVs processing for TE, RI & SR")
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

1 files changed, 83 insertions, 18 deletions

diff --git a/isisd/isis_te.c b/isisd/isis_te.c
index 0093279cd..c7a179255 100644
--- a/isisd/isis_te.c
+++ b/isisd/isis_te.c
@@ -66,6 +66,8 @@
 
 DEFINE_MTYPE_STATIC(ISISD, ISIS_MPLS_TE,    "ISIS MPLS_TE parameters");
 
+static void isis_mpls_te_circuit_ip_update(struct isis_circuit *circuit);
+
 /*------------------------------------------------------------------------*
  * Following are control functions for MPLS-TE parameters management.
  *------------------------------------------------------------------------*/
@@ -111,9 +113,13 @@ void isis_mpls_te_create(struct isis_area *area)
 	if (area->mta->ted)
 		isis_te_init_ted(area);
 
-	/* Update Extended TLVs according to Interface link parameters */
-	for (ALL_LIST_ELEMENTS_RO(area->circuit_list, node, circuit))
+	/* Update Extended TLVs according to Interface link parameters
+	 * and neighbor IP addresses
+	 */
+	for (ALL_LIST_ELEMENTS_RO(area->circuit_list, node, circuit)) {
 		isis_link_params_update(circuit, circuit->interface);
+		isis_mpls_te_circuit_ip_update(circuit);
+	}
 }
 
 /**
@@ -336,16 +342,12 @@ void isis_link_params_update(struct isis_circuit *circuit,
 	return;
 }
 
-static int isis_mpls_te_adj_ip_enabled(struct isis_adjacency *adj, int family,
-				       bool global)
+static int _isis_mpls_te_adj_ip_enabled(struct isis_adjacency *adj, int family,
+					bool global)
 {
 	struct isis_circuit *circuit;
 	struct isis_ext_subtlvs *ext;
 
-	/* Sanity Check */
-	if (!adj || !adj->circuit)
-		return 0;
-
 	circuit = adj->circuit;
 
 	/* Check that MPLS TE is enabled */
@@ -366,6 +368,12 @@ static int isis_mpls_te_adj_ip_enabled(struct isis_adjacency *adj, int family,
 		}
 		break;
 	case AF_INET6:
+		/* Nothing to do for link-local addresses - ie. not global.
+		 * https://datatracker.ietf.org/doc/html/rfc6119#section-3.1.1
+		 * Because the IPv6 traffic engineering TLVs present in LSPs are
+		 * propagated across networks, they MUST NOT use link-local
+		 * addresses.
+		 */
 		if (!global)
 			return 0;
 
@@ -381,22 +389,32 @@ static int isis_mpls_te_adj_ip_enabled(struct isis_adjacency *adj, int family,
 		return 0;
 	}
 
-	/* Update LSP */
-	lsp_regenerate_schedule(circuit->area, circuit->is_type, 0);
-
 	return 0;
 }
 
-static int isis_mpls_te_adj_ip_disabled(struct isis_adjacency *adj, int family,
-					bool global)
+static int isis_mpls_te_adj_ip_enabled(struct isis_adjacency *adj, int family,
+				       bool global)
 {
-	struct isis_circuit *circuit;
-	struct isis_ext_subtlvs *ext;
+	int ret;
 
 	/* Sanity Check */
-	if (!adj || !adj->circuit || !adj->circuit->ext)
+	if (!adj || !adj->circuit)
 		return 0;
 
+	ret = _isis_mpls_te_adj_ip_enabled(adj, family, global);
+
+	/* Update LSP */
+	lsp_regenerate_schedule(adj->circuit->area, adj->circuit->is_type, 0);
+
+	return ret;
+}
+
+static int _isis_mpls_te_adj_ip_disabled(struct isis_adjacency *adj, int family,
+					 bool global)
+{
+	struct isis_circuit *circuit;
+	struct isis_ext_subtlvs *ext;
+
 	circuit = adj->circuit;
 
 	/* Check that MPLS TE is enabled */
@@ -422,12 +440,59 @@ static int isis_mpls_te_adj_ip_disabled(struct isis_adjacency *adj, int family,
 		return 0;
 	}
 
+	return 0;
+}
+
+static int isis_mpls_te_adj_ip_disabled(struct isis_adjacency *adj, int family,
+					bool global)
+{
+	int ret;
+
+	/* Sanity Check */
+	if (!adj || !adj->circuit || !adj->circuit->ext)
+		return 0;
+
+	ret = _isis_mpls_te_adj_ip_disabled(adj, family, global);
+
 	/* Update LSP */
-	lsp_regenerate_schedule(circuit->area, circuit->is_type, 0);
+	lsp_regenerate_schedule(adj->circuit->area, adj->circuit->is_type, 0);
 
-	return 0;
+	return ret;
 }
 
+static void isis_mpls_te_circuit_ip_update(struct isis_circuit *circuit)
+{
+	struct isis_adjacency *adj;
+
+	/* https://datatracker.ietf.org/doc/html/rfc6119#section-3.2.3
+	 * This sub-TLV of the Extended IS Reachability TLV is used for point-
+	 * to-point links
+	 */
+	if (circuit->circ_type != CIRCUIT_T_P2P)
+		return;
+
+	adj = circuit->u.p2p.neighbor;
+
+	if (!adj)
+		return;
+
+	/* Nothing to do for link-local addresses.
+	 * https://datatracker.ietf.org/doc/html/rfc6119#section-3.1.1
+	 * Because the IPv6 traffic engineering TLVs present in LSPs are
+	 * propagated across networks, they MUST NOT use link-local addresses.
+	 */
+	if (adj->ipv4_address_count > 0)
+		_isis_mpls_te_adj_ip_enabled(adj, AF_INET, false);
+	else
+		_isis_mpls_te_adj_ip_disabled(adj, AF_INET, false);
+
+	if (adj->global_ipv6_count > 0)
+		_isis_mpls_te_adj_ip_enabled(adj, AF_INET6, true);
+	else
+		_isis_mpls_te_adj_ip_disabled(adj, AF_INET6, true);
+}
+
+
 int isis_mpls_te_update(struct interface *ifp)
 {
 	struct isis_circuit *circuit;