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-rw-r--r--bgpd/bgp_label.c476
1 files changed, 476 insertions, 0 deletions
diff --git a/bgpd/bgp_label.c b/bgpd/bgp_label.c
new file mode 100644
index 0000000..38f34a8
--- /dev/null
+++ b/bgpd/bgp_label.c
@@ -0,0 +1,476 @@
+/* BGP carrying label information
+ * Copyright (C) 2013 Cumulus Networks, Inc.
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * GNU Zebra is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <zebra.h>
+
+#include "command.h"
+#include "thread.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 "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;
+
+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, 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 = pi->extra ? pi->extra->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 %pRN label_index=%u label=%u",
+ __func__, reg ? "" : "un", bgp_dest_to_rnode(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;
+ }
+
+ bgp_dest_unlock_node(dest);
+
+ if (BGP_DEBUG(labelpool, LABELPOOL))
+ zlog_debug("%s: FEC %pRN label=%u, allocated=%d", __func__,
+ bgp_dest_to_rnode(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;
+
+ 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;
+ }
+
+ /* 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);
+ 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);
+ bgp_notify_send(peer, BGP_NOTIFY_UPDATE_ERR,
+ BGP_NOTIFY_UPDATE_INVAL_NETWORK);
+ 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, attr, 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;
+}
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