Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 466 insertions, 0 deletions

diff --git a/bgpd/bgp_addpath.c b/bgpd/bgp_addpath.c
new file mode 100644
index 0000000..d822f6e
--- /dev/null
+++ b/bgpd/bgp_addpath.c
@@ -0,0 +1,466 @@
+/*
+ * Addpath TX ID selection, and related utilities
+ * Copyright (C) 2018  Amazon.com, Inc. or its affiliates
+ *
+ * This program 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 of the License, or (at your option)
+ * any later version.
+ *
+ * This program 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
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "bgp_addpath.h"
+#include "bgp_route.h"
+
+static const struct bgp_addpath_strategy_names strat_names[BGP_ADDPATH_MAX] = {
+	{
+		.config_name = "addpath-tx-all-paths",
+		.human_name = "All",
+		.human_description = "Advertise all paths via addpath",
+		.type_json_name = "addpathTxAllPaths",
+		.id_json_name = "addpathTxIdAll"
+	},
+	{
+		.config_name = "addpath-tx-bestpath-per-AS",
+		.human_name = "Best-Per-AS",
+		.human_description = "Advertise bestpath per AS via addpath",
+		.type_json_name = "addpathTxBestpathPerAS",
+		.id_json_name = "addpathTxIdBestPerAS"
+	}
+};
+
+static const struct bgp_addpath_strategy_names unknown_names = {
+	.config_name = "addpath-tx-unknown",
+	.human_name = "Unknown-Addpath-Strategy",
+	.human_description = "Unknown Addpath Strategy",
+	.type_json_name = "addpathTxUnknown",
+	.id_json_name = "addpathTxIdUnknown"
+};
+
+/*
+ * Returns a structure full of strings associated with an addpath type. Will
+ * never return null.
+ */
+const struct bgp_addpath_strategy_names *
+bgp_addpath_names(enum bgp_addpath_strat strat)
+{
+	if (strat < BGP_ADDPATH_MAX)
+		return &(strat_names[strat]);
+	else
+		return &unknown_names;
+};
+
+/*
+ * Returns if any peer is transmitting addpaths for a given afi/safi.
+ */
+bool bgp_addpath_is_addpath_used(struct bgp_addpath_bgp_data *d, afi_t afi,
+				 safi_t safi)
+{
+	return d->total_peercount[afi][safi] > 0;
+}
+
+/*
+ * Initialize the BGP instance level data for addpath.
+ */
+void bgp_addpath_init_bgp_data(struct bgp_addpath_bgp_data *d)
+{
+	safi_t safi;
+	afi_t afi;
+	int i;
+
+	FOREACH_AFI_SAFI (afi, safi) {
+		for (i = 0; i < BGP_ADDPATH_MAX; i++) {
+			d->id_allocators[afi][safi][i] = NULL;
+			d->peercount[afi][safi][i] = 0;
+		}
+		d->total_peercount[afi][safi] = 0;
+	}
+}
+
+/*
+ * Free up resources associated with BGP route info structures.
+ */
+void bgp_addpath_free_info_data(struct bgp_addpath_info_data *d,
+			      struct bgp_addpath_node_data *nd)
+{
+	int i;
+
+	for (i = 0; i < BGP_ADDPATH_MAX; i++) {
+		if (d->addpath_tx_id[i] != IDALLOC_INVALID)
+			idalloc_free_to_pool(&nd->free_ids[i],
+					     d->addpath_tx_id[i]);
+	}
+}
+
+/*
+ * Return the addpath ID used to send a particular route, to a particular peer,
+ * in a particular AFI/SAFI.
+ */
+uint32_t bgp_addpath_id_for_peer(struct peer *peer, afi_t afi, safi_t safi,
+				struct bgp_addpath_info_data *d)
+{
+	if (peer->addpath_type[afi][safi] < BGP_ADDPATH_MAX)
+		return d->addpath_tx_id[peer->addpath_type[afi][safi]];
+	else
+		return IDALLOC_INVALID;
+}
+
+/*
+ * Returns true if the path has an assigned addpath ID for any of the addpath
+ * strategies.
+ */
+bool bgp_addpath_info_has_ids(struct bgp_addpath_info_data *d)
+{
+	int i;
+
+	for (i = 0; i < BGP_ADDPATH_MAX; i++)
+		if (d->addpath_tx_id[i] != 0)
+			return true;
+
+	return false;
+}
+
+/*
+ * Releases any ID's associated with the BGP prefix.
+ */
+void bgp_addpath_free_node_data(struct bgp_addpath_bgp_data *bd,
+			      struct bgp_addpath_node_data *nd, afi_t afi,
+			      safi_t safi)
+{
+	int i;
+
+	for (i = 0; i < BGP_ADDPATH_MAX; i++) {
+		idalloc_drain_pool(bd->id_allocators[afi][safi][i],
+				   &(nd->free_ids[i]));
+	}
+}
+
+/*
+ * Check to see if the addpath strategy requires DMED to be configured to work.
+ */
+bool bgp_addpath_dmed_required(int strategy)
+{
+	return strategy == BGP_ADDPATH_BEST_PER_AS;
+}
+
+/*
+ * Return true if this is a path we should advertise due to a
+ * configured addpath-tx knob
+ */
+bool bgp_addpath_tx_path(enum bgp_addpath_strat strat, struct bgp_path_info *pi)
+{
+	switch (strat) {
+	case BGP_ADDPATH_NONE:
+		return false;
+	case BGP_ADDPATH_ALL:
+		return true;
+	case BGP_ADDPATH_BEST_PER_AS:
+		if (CHECK_FLAG(pi->flags, BGP_PATH_DMED_SELECTED))
+			return true;
+		else
+			return false;
+	default:
+		return false;
+	}
+}
+
+static void bgp_addpath_flush_type_rn(struct bgp *bgp, afi_t afi, safi_t safi,
+				      enum bgp_addpath_strat addpath_type,
+				      struct bgp_dest *dest)
+{
+	struct bgp_path_info *pi;
+
+	idalloc_drain_pool(
+		bgp->tx_addpath.id_allocators[afi][safi][addpath_type],
+		&(dest->tx_addpath.free_ids[addpath_type]));
+	for (pi = bgp_dest_get_bgp_path_info(dest); pi; pi = pi->next) {
+		if (pi->tx_addpath.addpath_tx_id[addpath_type]
+		    != IDALLOC_INVALID) {
+			idalloc_free(
+				bgp->tx_addpath
+					.id_allocators[afi][safi][addpath_type],
+				pi->tx_addpath.addpath_tx_id[addpath_type]);
+			pi->tx_addpath.addpath_tx_id[addpath_type] =
+				IDALLOC_INVALID;
+		}
+	}
+}
+
+/*
+ * Purge all addpath ID's on a BGP instance associated with the addpath
+ * strategy, and afi/safi combination. This lets us let go of all memory held to
+ * track ID numbers associated with an addpath type not in use. Since
+ * post-bestpath ID processing is skipped for types not used, this is the only
+ * chance to free this data.
+ */
+static void bgp_addpath_flush_type(struct bgp *bgp, afi_t afi, safi_t safi,
+				   enum bgp_addpath_strat addpath_type)
+{
+	struct bgp_dest *dest, *ndest;
+
+	for (dest = bgp_table_top(bgp->rib[afi][safi]); dest;
+	     dest = bgp_route_next(dest)) {
+		if (safi == SAFI_MPLS_VPN) {
+			struct bgp_table *table;
+
+			table = bgp_dest_get_bgp_table_info(dest);
+			if (!table)
+				continue;
+
+			for (ndest = bgp_table_top(table); ndest;
+			     ndest = bgp_route_next(ndest))
+				bgp_addpath_flush_type_rn(bgp, afi, safi,
+							  addpath_type, ndest);
+		} else {
+			bgp_addpath_flush_type_rn(bgp, afi, safi, addpath_type,
+						  dest);
+		}
+	}
+
+	idalloc_destroy(bgp->tx_addpath.id_allocators[afi][safi][addpath_type]);
+	bgp->tx_addpath.id_allocators[afi][safi][addpath_type] = NULL;
+}
+
+/*
+ * Allocate an Addpath ID for the given type on a path, if necessary.
+ */
+static void bgp_addpath_populate_path(struct id_alloc *allocator,
+				      struct bgp_path_info *path,
+				      enum bgp_addpath_strat addpath_type)
+{
+	if (bgp_addpath_tx_path(addpath_type, path)) {
+		path->tx_addpath.addpath_tx_id[addpath_type] =
+			idalloc_allocate(allocator);
+	}
+}
+
+/*
+ * Compute addpath ID's on a BGP instance associated with the addpath strategy,
+ * and afi/safi combination. Since we won't waste the time computing addpath IDs
+ * for unused strategies, the first time a peer is configured to use a strategy,
+ * we have to backfill the data.
+ */
+static void bgp_addpath_populate_type(struct bgp *bgp, afi_t afi, safi_t safi,
+				    enum bgp_addpath_strat addpath_type)
+{
+	struct bgp_dest *dest, *ndest;
+	char buf[200];
+	struct id_alloc *allocator;
+
+	snprintf(buf, sizeof(buf), "Addpath ID Allocator %s:%d/%d",
+		 bgp_addpath_names(addpath_type)->config_name, (int)afi,
+		 (int)safi);
+	buf[sizeof(buf) - 1] = '\0';
+	zlog_info("Computing addpath IDs for addpath type %s",
+		bgp_addpath_names(addpath_type)->human_name);
+
+	bgp->tx_addpath.id_allocators[afi][safi][addpath_type] =
+		idalloc_new(buf);
+
+	idalloc_reserve(bgp->tx_addpath.id_allocators[afi][safi][addpath_type],
+		BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
+
+	allocator = bgp->tx_addpath.id_allocators[afi][safi][addpath_type];
+
+	for (dest = bgp_table_top(bgp->rib[afi][safi]); dest;
+	     dest = bgp_route_next(dest)) {
+		struct bgp_path_info *bi;
+
+		if (safi == SAFI_MPLS_VPN) {
+			struct bgp_table *table;
+
+			table = bgp_dest_get_bgp_table_info(dest);
+			if (!table)
+				continue;
+
+			for (ndest = bgp_table_top(table); ndest;
+			     ndest = bgp_route_next(ndest))
+				for (bi = bgp_dest_get_bgp_path_info(ndest); bi;
+				     bi = bi->next)
+					bgp_addpath_populate_path(allocator, bi,
+								  addpath_type);
+		} else {
+			for (bi = bgp_dest_get_bgp_path_info(dest); bi;
+			     bi = bi->next)
+				bgp_addpath_populate_path(allocator, bi,
+							  addpath_type);
+		}
+	}
+}
+
+/*
+ * Handle updates to a peer or group's addpath strategy. If after adjusting
+ * counts a addpath strategy is in use for the first time, or no longer in use,
+ * the IDs for that strategy will be populated or flushed.
+ */
+void bgp_addpath_type_changed(struct bgp *bgp)
+{
+	afi_t afi;
+	safi_t safi;
+	struct listnode *node, *nnode;
+	struct peer *peer;
+	int peer_count[AFI_MAX][SAFI_MAX][BGP_ADDPATH_MAX];
+	enum bgp_addpath_strat type;
+
+	FOREACH_AFI_SAFI(afi, safi) {
+		for (type=0; type<BGP_ADDPATH_MAX; type++) {
+			peer_count[afi][safi][type] = 0;
+		}
+		bgp->tx_addpath.total_peercount[afi][safi] = 0;
+	}
+
+	for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
+		FOREACH_AFI_SAFI(afi, safi) {
+			type = peer->addpath_type[afi][safi];
+			if (type != BGP_ADDPATH_NONE) {
+				peer_count[afi][safi][type] += 1;
+				bgp->tx_addpath.total_peercount[afi][safi] += 1;
+			}
+		}
+	}
+
+	FOREACH_AFI_SAFI(afi, safi) {
+		for (type=0; type<BGP_ADDPATH_MAX; type++) {
+			int old = bgp->tx_addpath.peercount[afi][safi][type];
+			int new = peer_count[afi][safi][type];
+
+			bgp->tx_addpath.peercount[afi][safi][type] = new;
+
+			if (old == 0 && new != 0) {
+				bgp_addpath_populate_type(bgp, afi, safi,
+					type);
+			} else if (old != 0 && new == 0) {
+				bgp_addpath_flush_type(bgp, afi, safi, type);
+			}
+		}
+	}
+}
+
+/*
+ * Change the addpath type assigned to a peer, or peer group. In addition to
+ * adjusting the counts, peer sessions will be reset as needed to make the
+ * change take effect.
+ */
+void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
+			      enum bgp_addpath_strat addpath_type)
+{
+	struct bgp *bgp = peer->bgp;
+	enum bgp_addpath_strat old_type = peer->addpath_type[afi][safi];
+	struct listnode *node, *nnode;
+	struct peer *tmp_peer;
+	struct peer_group *group;
+
+	if (addpath_type == old_type)
+		return;
+
+	if (addpath_type == BGP_ADDPATH_NONE && peer->group &&
+	    !CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		/* A "no" config on a group member inherits group */
+		addpath_type = peer->group->conf->addpath_type[afi][safi];
+	}
+
+	peer->addpath_type[afi][safi] = addpath_type;
+
+	bgp_addpath_type_changed(bgp);
+
+	if (addpath_type != BGP_ADDPATH_NONE) {
+		if (bgp_addpath_dmed_required(addpath_type)) {
+			if (!CHECK_FLAG(bgp->flags,
+					BGP_FLAG_DETERMINISTIC_MED)) {
+				zlog_warn(
+					"%s: enabling bgp deterministic-med, this is required for addpath-tx-bestpath-per-AS",
+					peer->host);
+				SET_FLAG(bgp->flags,
+					 BGP_FLAG_DETERMINISTIC_MED);
+				bgp_recalculate_all_bestpaths(bgp);
+			}
+		}
+	}
+
+	zlog_info("Resetting peer %s%s due to change in addpath config",
+		  CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP) ? "group " : "",
+		  peer->host);
+
+	if (CHECK_FLAG(peer->sflags, PEER_STATUS_GROUP)) {
+		group = peer->group;
+
+		/* group will be null as peer_group_delete calls peer_delete on
+		 * group->conf. That peer_delete will eventuallly end up here
+		 * if the group was configured to tx addpaths.
+		 */
+		if (group != NULL) {
+			for (ALL_LIST_ELEMENTS(group->peer, node, nnode,
+			     tmp_peer)) {
+				if (tmp_peer->addpath_type[afi][safi] ==
+				    old_type) {
+					bgp_addpath_set_peer_type(tmp_peer,
+								 afi,
+								 safi,
+								 addpath_type);
+				}
+			}
+		}
+	} else {
+		peer_change_action(peer, afi, safi, peer_change_reset);
+	}
+
+}
+
+/*
+ * Intended to run after bestpath. This function will take TX IDs from paths
+ * that no longer need them, and give them to paths that do. This prevents
+ * best-per-as updates from needing to do a separate withdraw and update just to
+ * swap out which path is sent.
+ */
+void bgp_addpath_update_ids(struct bgp *bgp, struct bgp_dest *bn, afi_t afi,
+			    safi_t safi)
+{
+	int i;
+	struct bgp_path_info *pi;
+	struct id_alloc_pool **pool_ptr;
+
+	for (i = 0; i < BGP_ADDPATH_MAX; i++) {
+		struct id_alloc *alloc =
+			bgp->tx_addpath.id_allocators[afi][safi][i];
+		pool_ptr = &(bn->tx_addpath.free_ids[i]);
+
+		if (bgp->tx_addpath.peercount[afi][safi][i] == 0)
+			continue;
+
+		/* Free Unused IDs back to the pool.*/
+		for (pi = bgp_dest_get_bgp_path_info(bn); pi; pi = pi->next) {
+			if (pi->tx_addpath.addpath_tx_id[i] != IDALLOC_INVALID
+			    && !bgp_addpath_tx_path(i, pi)) {
+				idalloc_free_to_pool(pool_ptr,
+					pi->tx_addpath.addpath_tx_id[i]);
+				pi->tx_addpath.addpath_tx_id[i] =
+					IDALLOC_INVALID;
+			}
+		}
+
+		/* Give IDs to paths that need them (pulling from the pool) */
+		for (pi = bgp_dest_get_bgp_path_info(bn); pi; pi = pi->next) {
+			if (pi->tx_addpath.addpath_tx_id[i] == IDALLOC_INVALID
+			    && bgp_addpath_tx_path(i, pi)) {
+				pi->tx_addpath.addpath_tx_id[i] =
+					idalloc_allocate_prefer_pool(
+						alloc, pool_ptr);
+			}
+		}
+
+		/* Free any IDs left in the pool to the main allocator */
+		idalloc_drain_pool(alloc, pool_ptr);
+	}
+}