bgpd: store bgp link-state prefixes

Add the ability to store link-state prefixes in the BGP table.
Store a raw copy of the BGP link state NLRI TLVs as received in the
packet in 'p.u.prefix_linkstate.ptr'.

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

bgpd/bgp_errors.c

@@ -449,6 +449,12 @@ static struct log_ref ferr_bgp_err[] = {
 		.description = "The BGP flowspec subsystem has detected that there was a failure for installation/removal/modification of Flowspec from the dataplane",
 		.suggestion = "Gather log files from the router and open an issue, Restart FRR"
 	},
+	{
+		.code = EC_BGP_LINKSTATE_PACKET,
+		.title = "BGP Link-State packet processing error",
+		.description = "The BGP Link-State subsystem has detected a error in the send or receive of a packet",
+		.suggestion = "Gather log files from both sides of the peering relationship and open an issue"
+	},
 	{
 		.code = EC_BGP_DOPPELGANGER_CONFIG,
 		.title = "BGP has detected a configuration overwrite during peer collision resolution",

bgpd/bgp_errors.h

@@ -59,6 +59,7 @@ enum bgp_log_refs {
 	EC_BGP_EVPN_INSTANCE_MISMATCH,
 	EC_BGP_FLOWSPEC_PACKET,
 	EC_BGP_FLOWSPEC_INSTALLATION,
+	EC_BGP_LINKSTATE_PACKET,
 	EC_BGP_ASPATH_FEWER_HOPS,
 	EC_BGP_DEFUNCT_SNPA_LEN,
 	EC_BGP_MISSING_ATTRIBUTE,

bgpd/bgp_linkstate_tlv.c

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* BGP Link-State TLV Serializer/Deserializer
+ * Copyright 2023 6WIND S.A.
+ */
+
+#include <zebra.h>
+
+#include "bgpd/bgpd.h"
+#include "bgpd/bgp_route.h"
+#include "bgpd/bgp_debug.h"
+#include "bgpd/bgp_errors.h"
+#include "bgpd/bgp_linkstate_tlv.h"
+
+
+static uint16_t pnt_decode16(uint8_t **pnt)
+{
+	uint16_t data;
+
+	*pnt = ptr_get_be16(*pnt, &data);
+
+	return data;
+}
+
+int bgp_nlri_parse_linkstate(struct peer *peer, struct attr *attr,
+			     struct bgp_nlri *packet, int withdraw)
+{
+	uint8_t *pnt;
+	uint8_t *lim;
+	afi_t afi;
+	safi_t safi;
+	uint16_t length = 0;
+	struct prefix p;
+
+	/* Start processing the NLRI - there may be multiple in the MP_REACH */
+	pnt = packet->nlri;
+	lim = pnt + packet->length;
+	afi = packet->afi;
+	safi = packet->safi;
+
+	for (; pnt < lim; pnt += length) {
+		/* Clear prefix structure. */
+		memset(&p, 0, sizeof(p));
+
+		/* All linkstate NLRI begin with NRLI type and length. */
+		if (pnt + 4 > lim)
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+
+		p.u.prefix_linkstate.nlri_type = pnt_decode16(&pnt);
+		length = pnt_decode16(&pnt);
+		/* When packet overflow occur return immediately. */
+		if (pnt + length > lim) {
+			flog_err(
+				EC_BGP_LINKSTATE_PACKET,
+				"Link-State NLRI length inconsistent (size %u seen)",
+				length);
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+		}
+		p.family = AF_LINKSTATE;
+
+		p.u.prefix_linkstate.ptr = (uintptr_t)pnt;
+		p.prefixlen = length;
+
+		/* Process the route. */
+		if (withdraw)
+			bgp_withdraw(peer, &p, 0, afi, safi, ZEBRA_ROUTE_BGP,
+				     BGP_ROUTE_NORMAL, NULL, NULL, 0, NULL);
+		else
+			bgp_update(peer, &p, 0, attr, afi, safi,
+				   ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL, NULL,
+				   NULL, 0, 0, NULL);
+	}
+	return BGP_NLRI_PARSE_OK;
+}

bgpd/bgp_linkstate_tlv.h

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* BGP Link-State TLV Serializer/Deserializer header
+ * Copyright 2023 6WIND S.A.
+ */
+
+#ifndef BGP_LINKSTATE_TLV_H
+#define BGP_LINKSTATE_TLV_H
+
+extern int bgp_nlri_parse_linkstate(struct peer *peer, struct attr *attr,
+				    struct bgp_nlri *packet, int withdraw);
+
+#endif /* BGP_LINKSTATE_TLV_H */

bgpd/bgp_packet.c

@@ -48,6 +48,7 @@
 #include "bgpd/bgp_io.h"
 #include "bgpd/bgp_keepalives.h"
 #include "bgpd/bgp_flowspec.h"
+#include "bgpd/bgp_linkstate_tlv.h"
 #include "bgpd/bgp_trace.h"
 
 DEFINE_HOOK(bgp_packet_dump,
@@ -349,7 +350,11 @@ int bgp_nlri_parse(struct peer *peer, struct attr *attr,
 		return bgp_nlri_parse_evpn(peer, attr, packet, mp_withdraw);
 	case SAFI_FLOWSPEC:
 		return bgp_nlri_parse_flowspec(peer, attr, packet, mp_withdraw);
+	case SAFI_LINKSTATE:
+		return bgp_nlri_parse_linkstate(peer, attr, packet,
+						mp_withdraw);
 	}
+
 	return BGP_NLRI_PARSE_ERROR;
 }
 

bgpd/bgp_table.c

@@ -117,6 +117,9 @@ static void bgp_node_destroy(route_table_delegate_t *delegate,
 		node->info = NULL;
 	}
 
+	if (family2afi(node->p.family) == AFI_LINKSTATE)
+		prefix_linkstate_ptr_free(&node->p);
+
 	XFREE(MTYPE_ROUTE_NODE, node);
 }
 

bgpd/subdir.am

@@ -51,6 +51,7 @@ bgpd_libbgp_a_SOURCES = \
 	bgpd/bgp_label.c \
 	bgpd/bgp_labelpool.c \
 	bgpd/bgp_lcommunity.c \
+	bgpd/bgp_linkstate_tlv.c \
 	bgpd/bgp_mac.c \
 	bgpd/bgp_memory.c \
 	bgpd/bgp_mpath.c \
@@ -133,6 +134,7 @@ noinst_HEADERS += \
 	bgpd/bgp_label.h \
 	bgpd/bgp_labelpool.h \
 	bgpd/bgp_lcommunity.h \
+	bgpd/bgp_linkstate_tlv.h \
 	bgpd/bgp_mac.h \
 	bgpd/bgp_memory.h \
 	bgpd/bgp_mpath.h \

lib/table.c

@@ -281,15 +281,22 @@ struct route_node *route_node_get(struct route_table *table,
 	const uint8_t *prefix = &p->u.prefix;
 
 	node = rn_hash_node_find(&table->hash, &search);
-	if (node && node->info)
+	if (node && node->info) {
+		if (family2afi(p->family) == AFI_LINKSTATE)
+			prefix_linkstate_ptr_free(p);
+
 		return route_lock_node(node);
+	}
 
 	match = NULL;
 	node = table->top;
 	while (node && node->p.prefixlen <= prefixlen
 	       && prefix_match(&node->p, p)) {
-		if (node->p.prefixlen == prefixlen)
+		if (node->p.prefixlen == prefixlen) {
+			if (family2afi(p->family) == AFI_LINKSTATE)
+				prefix_linkstate_ptr_free(p);
 			return route_lock_node(node);
+		}
 
 		match = node;
 		node = node->link[prefix_bit(prefix, node->p.prefixlen)];
@@ -324,6 +331,9 @@ struct route_node *route_node_get(struct route_table *table,
 	table->count++;
 	route_lock_node(new);
 
+	if (family2afi(p->family) == AFI_LINKSTATE)
+		prefix_linkstate_ptr_free(p);
+
 	return new;
 }