1 files changed, 610 insertions, 0 deletions

diff --git a/bgpd/bgp_label.c b/bgpd/bgp_label.c
new file mode 100644
index 00000000..f03b820d
--- /dev/null
+++ b/bgpd/bgp_label.c
@@ -0,0 +1,610 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* BGP carrying label information
+ * Copyright (C) 2013 Cumulus Networks, Inc.
+ */
+
+#include <zebra.h>
+
+#include "command.h"
+#include "frrevent.h"
+#include "prefix.h"
+#include "zclient.h"
+#include "stream.h"
+#include "network.h"
+#include "log.h"
+#include "memory.h"
+#include "nexthop.h"
+#include "mpls.h"
+#include "jhash.h"
+
+#include "bgpd/bgpd.h"
+#include "bgpd/bgp_table.h"
+#include "bgpd/bgp_route.h"
+#include "bgpd/bgp_attr.h"
+#include "bgpd/bgp_label.h"
+#include "bgpd/bgp_packet.h"
+#include "bgpd/bgp_debug.h"
+#include "bgpd/bgp_errors.h"
+
+extern struct zclient *zclient;
+
+
+/* MPLS Labels hash routines. */
+static struct hash *labels_hash;
+
+static void *bgp_labels_hash_alloc(void *p)
+{
+	const struct bgp_labels *labels = p;
+	struct bgp_labels *new;
+	uint8_t i;
+
+	new = XMALLOC(MTYPE_BGP_LABELS, sizeof(struct bgp_labels));
+
+	new->num_labels = labels->num_labels;
+	for (i = 0; i < labels->num_labels; i++)
+		new->label[i] = labels->label[i];
+
+	return new;
+}
+
+static uint32_t bgp_labels_hash_key_make(const void *p)
+{
+	const struct bgp_labels *labels = p;
+	uint32_t key = 0;
+
+	if (labels->num_labels)
+		key = jhash(&labels->label,
+			    labels->num_labels * sizeof(mpls_label_t), key);
+
+	return key;
+}
+
+static bool bgp_labels_hash_cmp(const void *p1, const void *p2)
+{
+	return bgp_labels_cmp(p1, p2);
+}
+
+void bgp_labels_init(void)
+{
+	labels_hash = hash_create(bgp_labels_hash_key_make, bgp_labels_hash_cmp,
+				  "BGP Labels hash");
+}
+
+/*
+ * special for hash_clean below
+ */
+static void bgp_labels_free(void *labels)
+{
+	XFREE(MTYPE_BGP_LABELS, labels);
+}
+
+void bgp_labels_finish(void)
+{
+	hash_clean_and_free(&labels_hash, bgp_labels_free);
+}
+
+struct bgp_labels *bgp_labels_intern(struct bgp_labels *labels)
+{
+	struct bgp_labels *find;
+
+	if (!labels)
+		return NULL;
+
+	if (!labels->num_labels)
+		/* do not intern void labels structure */
+		return NULL;
+
+	find = (struct bgp_labels *)hash_get(labels_hash, labels,
+					     bgp_labels_hash_alloc);
+	find->refcnt++;
+
+	return find;
+}
+
+void bgp_labels_unintern(struct bgp_labels **plabels)
+{
+	struct bgp_labels *labels = *plabels;
+	struct bgp_labels *ret;
+
+	if (!*plabels)
+		return;
+
+	/* Decrement labels reference. */
+	labels->refcnt--;
+
+	/* If reference becomes zero then free labels object. */
+	if (labels->refcnt == 0) {
+		ret = hash_release(labels_hash, labels);
+		assert(ret != NULL);
+		bgp_labels_free(labels);
+		*plabels = NULL;
+	}
+}
+
+bool bgp_labels_cmp(const struct bgp_labels *labels1,
+		    const struct bgp_labels *labels2)
+{
+	uint8_t i;
+
+	if (!labels1 && !labels2)
+		return true;
+
+	if (!labels1 && labels2)
+		return false;
+
+	if (labels1 && !labels2)
+		return false;
+
+	if (labels1->num_labels != labels2->num_labels)
+		return false;
+
+	for (i = 0; i < labels1->num_labels; i++) {
+		if (labels1->label[i] != labels2->label[i])
+			return false;
+	}
+
+	return true;
+}
+
+int bgp_parse_fec_update(void)
+{
+	struct stream *s;
+	struct bgp_dest *dest;
+	struct bgp *bgp;
+	struct bgp_table *table;
+	struct prefix p;
+	uint32_t label;
+	afi_t afi;
+	safi_t safi;
+
+	s = zclient->ibuf;
+
+	memset(&p, 0, sizeof(p));
+	p.family = stream_getw(s);
+	p.prefixlen = stream_getc(s);
+	stream_get(p.u.val, s, PSIZE(p.prefixlen));
+	label = stream_getl(s);
+
+	/* hack for the bgp instance & SAFI = have to send/receive it */
+	afi = family2afi(p.family);
+	safi = SAFI_UNICAST;
+	bgp = bgp_get_default();
+	if (!bgp) {
+		zlog_debug("no default bgp instance");
+		return -1;
+	}
+
+	table = bgp->rib[afi][safi];
+	if (!table) {
+		zlog_debug("no %u unicast table", p.family);
+		return -1;
+	}
+	dest = bgp_node_lookup(table, &p);
+	if (!dest) {
+		zlog_debug("no node for the prefix");
+		return -1;
+	}
+
+	/* treat it as implicit withdraw - the label is invalid */
+	if (label == MPLS_INVALID_LABEL)
+		bgp_unset_valid_label(&dest->local_label);
+	else {
+		dest->local_label = mpls_lse_encode(label, 0, 0, 1);
+		bgp_set_valid_label(&dest->local_label);
+	}
+	SET_FLAG(dest->flags, BGP_NODE_LABEL_CHANGED);
+	bgp_process(bgp, dest, NULL, afi, safi);
+	bgp_dest_unlock_node(dest);
+	return 1;
+}
+
+mpls_label_t bgp_adv_label(struct bgp_dest *dest, struct bgp_path_info *pi,
+			   struct peer *to, afi_t afi, safi_t safi)
+{
+	struct peer *from;
+	mpls_label_t remote_label;
+	int reflect;
+
+	if (!dest || !pi || !to)
+		return MPLS_INVALID_LABEL;
+
+	remote_label = BGP_PATH_INFO_NUM_LABELS(pi)
+			       ? pi->extra->labels->label[0]
+			       : MPLS_INVALID_LABEL;
+	from = pi->peer;
+	reflect =
+		((from->sort == BGP_PEER_IBGP) && (to->sort == BGP_PEER_IBGP));
+
+	if (reflect
+	    && !CHECK_FLAG(to->af_flags[afi][safi],
+			   PEER_FLAG_FORCE_NEXTHOP_SELF))
+		return remote_label;
+
+	if (CHECK_FLAG(to->af_flags[afi][safi], PEER_FLAG_NEXTHOP_UNCHANGED))
+		return remote_label;
+
+	return dest->local_label;
+}
+
+static void bgp_send_fec_register_label_msg(struct bgp_dest *dest, bool reg,
+					    uint32_t label_index)
+{
+	struct stream *s;
+	int command;
+	const struct prefix *p;
+	uint16_t flags = 0;
+	size_t flags_pos = 0;
+	mpls_label_t *local_label = &(dest->local_label);
+	uint32_t ttl = 0;
+	uint32_t bos = 0;
+	uint32_t exp = 0;
+	mpls_label_t label = MPLS_INVALID_LABEL;
+	bool have_label_to_reg;
+
+	mpls_lse_decode(*local_label, &label, &ttl, &exp, &bos);
+
+	have_label_to_reg = bgp_is_valid_label(local_label) &&
+			    label != MPLS_LABEL_IMPLICIT_NULL;
+
+	p = bgp_dest_get_prefix(dest);
+
+	/* Check socket. */
+	if (!zclient || zclient->sock < 0)
+		return;
+
+	if (BGP_DEBUG(labelpool, LABELPOOL))
+		zlog_debug("%s: FEC %sregister %pBD label_index=%u label=%u",
+			   __func__, reg ? "" : "un", dest, label_index, label);
+	/* If the route node has a local_label assigned or the
+	 * path node has an MPLS SR label index allowing zebra to
+	 * derive the label, proceed with registration. */
+	s = zclient->obuf;
+	stream_reset(s);
+	command = (reg) ? ZEBRA_FEC_REGISTER : ZEBRA_FEC_UNREGISTER;
+	zclient_create_header(s, command, VRF_DEFAULT);
+	flags_pos = stream_get_endp(s); /* save position of 'flags' */
+	stream_putw(s, flags);		/* initial flags */
+	stream_putw(s, PREFIX_FAMILY(p));
+	stream_put_prefix(s, p);
+	if (reg) {
+		/* label index takes precedence over auto-assigned label. */
+		if (label_index != 0) {
+			flags |= ZEBRA_FEC_REGISTER_LABEL_INDEX;
+			stream_putl(s, label_index);
+		} else if (have_label_to_reg) {
+			flags |= ZEBRA_FEC_REGISTER_LABEL;
+			stream_putl(s, label);
+		}
+		SET_FLAG(dest->flags, BGP_NODE_REGISTERED_FOR_LABEL);
+	} else
+		UNSET_FLAG(dest->flags, BGP_NODE_REGISTERED_FOR_LABEL);
+
+	/* Set length and flags */
+	stream_putw_at(s, 0, stream_get_endp(s));
+
+	/*
+	 * We only need to write new flags if this is a register
+	 */
+	if (reg)
+		stream_putw_at(s, flags_pos, flags);
+
+	zclient_send_message(zclient);
+}
+
+/**
+ * This is passed as the callback function to bgp_labelpool.c:bgp_lp_get()
+ * by bgp_reg_dereg_for_label() when a label needs to be obtained from
+ * label pool.
+ * Note that it will reject the allocated label if a label index is found,
+ * because the label index supposes predictable labels
+ */
+int bgp_reg_for_label_callback(mpls_label_t new_label, void *labelid,
+			       bool allocated)
+{
+	struct bgp_dest *dest;
+
+	dest = labelid;
+
+	/*
+	 * if the route had been removed or the request has gone then reject
+	 * the allocated label. The requesting code will have done what is
+	 * required to allocate the correct label
+	 */
+	if (!CHECK_FLAG(dest->flags, BGP_NODE_LABEL_REQUESTED)) {
+		bgp_dest_unlock_node(dest);
+		return -1;
+	}
+
+	dest = bgp_dest_unlock_node(dest);
+	assert(dest);
+
+	if (BGP_DEBUG(labelpool, LABELPOOL))
+		zlog_debug("%s: FEC %pBD label=%u, allocated=%d", __func__,
+			   dest, new_label, allocated);
+
+	if (!allocated) {
+		/*
+		 * previously-allocated label is now invalid, set to implicit
+		 * null until new label arrives
+		 */
+		if (CHECK_FLAG(dest->flags, BGP_NODE_REGISTERED_FOR_LABEL)) {
+			UNSET_FLAG(dest->flags, BGP_NODE_LABEL_REQUESTED);
+			dest->local_label = mpls_lse_encode(
+				MPLS_LABEL_IMPLICIT_NULL, 0, 0, 1);
+			bgp_set_valid_label(&dest->local_label);
+		}
+	}
+
+	dest->local_label = mpls_lse_encode(new_label, 0, 0, 1);
+	bgp_set_valid_label(&dest->local_label);
+
+	/*
+	 * Get back to registering the FEC
+	 */
+	bgp_send_fec_register_label_msg(dest, true, 0);
+
+	return 0;
+}
+
+void bgp_reg_dereg_for_label(struct bgp_dest *dest, struct bgp_path_info *pi,
+			     bool reg)
+{
+	bool with_label_index = false;
+	const struct prefix *p;
+	bool have_label_to_reg;
+	uint32_t ttl = 0;
+	uint32_t bos = 0;
+	uint32_t exp = 0;
+	mpls_label_t label = MPLS_INVALID_LABEL;
+
+	mpls_lse_decode(dest->local_label, &label, &ttl, &exp, &bos);
+
+	have_label_to_reg = bgp_is_valid_label(&dest->local_label) &&
+			    label != MPLS_LABEL_IMPLICIT_NULL;
+
+	p = bgp_dest_get_prefix(dest);
+
+	if (BGP_DEBUG(labelpool, LABELPOOL))
+		zlog_debug("%s: %pFX: %s ", __func__, p,
+			   (reg ? "reg" : "dereg"));
+
+	if (reg) {
+		assert(pi);
+		/*
+		 * Determine if we will let zebra should derive label from
+		 * label index instead of bgpd requesting from label pool
+		 */
+		if (CHECK_FLAG(pi->attr->flag,
+			    ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID))
+			&& pi->attr->label_index != BGP_INVALID_LABEL_INDEX) {
+			with_label_index = true;
+			UNSET_FLAG(dest->flags, BGP_NODE_LABEL_REQUESTED);
+		} else {
+			/*
+			 * If no label has been registered -- assume any label
+			 * from label pool will do. This means that label index
+			 * always takes precedence over auto-assigned labels.
+			 */
+			if (!have_label_to_reg) {
+				SET_FLAG(dest->flags, BGP_NODE_LABEL_REQUESTED);
+				if (BGP_DEBUG(labelpool, LABELPOOL))
+					zlog_debug(
+						"%s: Requesting label from LP for %pFX",
+						__func__, p);
+				/* bgp_reg_for_label_callback() will deal with
+				 * fec registration when it gets a label from
+				 * the pool. This means we'll never register
+				 * FECs withoutvalid labels.
+				 */
+				bgp_lp_get(LP_TYPE_BGP_LU, dest,
+					   bgp_reg_for_label_callback);
+				return;
+			}
+		}
+	} else {
+		UNSET_FLAG(dest->flags, BGP_NODE_LABEL_REQUESTED);
+		bgp_lp_release(LP_TYPE_BGP_LU, dest, label);
+	}
+
+	bgp_send_fec_register_label_msg(
+		dest, reg, with_label_index ? pi->attr->label_index : 0);
+}
+
+static int bgp_nlri_get_labels(struct peer *peer, uint8_t *pnt, uint8_t plen,
+			       mpls_label_t *label)
+{
+	uint8_t *data = pnt;
+	uint8_t *lim = pnt + plen;
+	uint8_t llen = 0;
+	uint8_t label_depth = 0;
+
+	if (plen < BGP_LABEL_BYTES)
+		return 0;
+
+	for (; data < lim; data += BGP_LABEL_BYTES) {
+		memcpy(label, data, BGP_LABEL_BYTES);
+		llen += BGP_LABEL_BYTES;
+
+		bgp_set_valid_label(label);
+		label_depth += 1;
+
+		if (bgp_is_withdraw_label(label) || label_bos(label))
+			break;
+	}
+
+	/* If we RX multiple labels we will end up keeping only the last
+	 * one. We do not yet support a label stack greater than 1. */
+	if (label_depth > 1)
+		zlog_info("%pBP rcvd UPDATE with label stack %d deep", peer,
+			  label_depth);
+
+	if (!(bgp_is_withdraw_label(label) || label_bos(label)))
+		flog_warn(
+			EC_BGP_INVALID_LABEL_STACK,
+			"%pBP rcvd UPDATE with invalid label stack - no bottom of stack",
+			peer);
+
+	return llen;
+}
+
+int bgp_nlri_parse_label(struct peer *peer, struct attr *attr,
+			 struct bgp_nlri *packet)
+{
+	uint8_t *pnt;
+	uint8_t *lim;
+	struct prefix p;
+	int psize = 0;
+	int prefixlen;
+	afi_t afi;
+	safi_t safi;
+	bool addpath_capable;
+	uint32_t addpath_id;
+	mpls_label_t label = MPLS_INVALID_LABEL;
+	uint8_t llen;
+
+	pnt = packet->nlri;
+	lim = pnt + packet->length;
+	afi = packet->afi;
+	safi = packet->safi;
+	addpath_id = 0;
+
+	addpath_capable = bgp_addpath_encode_rx(peer, afi, safi);
+
+	for (; pnt < lim; pnt += psize) {
+		/* Clear prefix structure. */
+		memset(&p, 0, sizeof(p));
+
+		if (addpath_capable) {
+
+			/* When packet overflow occurs return immediately. */
+			if (pnt + BGP_ADDPATH_ID_LEN > lim)
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+
+			memcpy(&addpath_id, pnt, BGP_ADDPATH_ID_LEN);
+			addpath_id = ntohl(addpath_id);
+			pnt += BGP_ADDPATH_ID_LEN;
+
+			if (pnt >= lim)
+				return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+		}
+
+		/* Fetch prefix length. */
+		prefixlen = *pnt++;
+		p.family = afi2family(packet->afi);
+		psize = PSIZE(prefixlen);
+
+		/* sanity check against packet data */
+		if ((pnt + psize) > lim) {
+			flog_err(
+				EC_BGP_UPDATE_RCV,
+				"%s [Error] Update packet error / L-U (prefix length %d exceeds packet size %u)",
+				peer->host, prefixlen, (uint)(lim - pnt));
+			return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW;
+		}
+
+		/* Fill in the labels */
+		llen = bgp_nlri_get_labels(peer, pnt, psize, &label);
+		if (llen == 0) {
+			flog_err(
+				EC_BGP_UPDATE_RCV,
+				"%s [Error] Update packet error (wrong label length 0)",
+				peer->host);
+			return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH;
+		}
+		p.prefixlen = prefixlen - BSIZE(llen);
+
+		/* There needs to be at least one label */
+		if (prefixlen < 24) {
+			flog_err(EC_BGP_UPDATE_RCV,
+				 "%s [Error] Update packet error (wrong label length %d)",
+				 peer->host, prefixlen);
+			return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH;
+		}
+
+		if ((afi == AFI_IP && p.prefixlen > IPV4_MAX_BITLEN)
+		    || (afi == AFI_IP6 && p.prefixlen > IPV6_MAX_BITLEN))
+			return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH;
+
+		/* Fetch prefix from NLRI packet */
+		memcpy(&p.u.prefix, pnt + llen, psize - llen);
+
+		/* Check address. */
+		if (afi == AFI_IP && safi == SAFI_LABELED_UNICAST) {
+			if (IN_CLASSD(ntohl(p.u.prefix4.s_addr))) {
+				/* From RFC4271 Section 6.3:
+				 *
+				 * If a prefix in the NLRI field is semantically
+				 * incorrect
+				 * (e.g., an unexpected multicast IP address),
+				 * an error SHOULD
+				 * be logged locally, and the prefix SHOULD be
+				 * ignored.
+				  */
+				flog_err(
+					EC_BGP_UPDATE_RCV,
+					"%s: IPv4 labeled-unicast NLRI is multicast address %pI4, ignoring",
+					peer->host, &p.u.prefix4);
+				continue;
+			}
+		}
+
+		/* Check address. */
+		if (afi == AFI_IP6 && safi == SAFI_LABELED_UNICAST) {
+			if (IN6_IS_ADDR_LINKLOCAL(&p.u.prefix6)) {
+				flog_err(
+					EC_BGP_UPDATE_RCV,
+					"%s: IPv6 labeled-unicast NLRI is link-local address %pI6, ignoring",
+					peer->host, &p.u.prefix6);
+
+				continue;
+			}
+
+			if (IN6_IS_ADDR_MULTICAST(&p.u.prefix6)) {
+				flog_err(
+					EC_BGP_UPDATE_RCV,
+					"%s: IPv6 unicast NLRI is multicast address %pI6, ignoring",
+					peer->host, &p.u.prefix6);
+
+				continue;
+			}
+		}
+
+		if (attr) {
+			bgp_update(peer, &p, addpath_id, attr, packet->afi,
+				   safi, ZEBRA_ROUTE_BGP, BGP_ROUTE_NORMAL,
+				   NULL, &label, 1, 0, NULL);
+		} else {
+			bgp_withdraw(peer, &p, addpath_id, packet->afi,
+				     SAFI_UNICAST, ZEBRA_ROUTE_BGP,
+				     BGP_ROUTE_NORMAL, NULL, &label, 1, NULL);
+		}
+	}
+
+	/* Packet length consistency check. */
+	if (pnt != lim) {
+		flog_err(
+			EC_BGP_UPDATE_RCV,
+			"%s [Error] Update packet error / L-U (%td data remaining after parsing)",
+			peer->host, lim - pnt);
+		return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH;
+	}
+
+	return BGP_NLRI_PARSE_OK;
+}
+
+bool bgp_labels_same(const mpls_label_t *tbl_a, const uint8_t num_labels_a,
+		     const mpls_label_t *tbl_b, const uint8_t num_labels_b)
+{
+	uint32_t i;
+
+	if (num_labels_a != num_labels_b)
+		return false;
+	if (num_labels_a == 0)
+		return true;
+
+	for (i = 0; i < num_labels_a; i++) {
+		if (tbl_a[i] != tbl_b[i])
+			return false;
+	}
+	return true;
+}