diff options
Diffstat (limited to 'bgpd/bgp_mpath.c')
| -rw-r--r-- | bgpd/bgp_mpath.c | 931 |
1 files changed, 931 insertions, 0 deletions
diff --git a/bgpd/bgp_mpath.c b/bgpd/bgp_mpath.c new file mode 100644 index 0000000..64af8a5 --- /dev/null +++ b/bgpd/bgp_mpath.c @@ -0,0 +1,931 @@ +/* + * BGP Multipath + * Copyright (C) 2010 Google Inc. + * + * This file is part of Quagga + * + * Quagga 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. + * + * Quagga 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 "prefix.h" +#include "linklist.h" +#include "sockunion.h" +#include "memory.h" +#include "queue.h" +#include "filter.h" + +#include "bgpd/bgpd.h" +#include "bgpd/bgp_table.h" +#include "bgpd/bgp_route.h" +#include "bgpd/bgp_attr.h" +#include "bgpd/bgp_debug.h" +#include "bgpd/bgp_aspath.h" +#include "bgpd/bgp_community.h" +#include "bgpd/bgp_ecommunity.h" +#include "bgpd/bgp_lcommunity.h" +#include "bgpd/bgp_mpath.h" + +/* + * bgp_maximum_paths_set + * + * Record maximum-paths configuration for BGP instance + */ +int bgp_maximum_paths_set(struct bgp *bgp, afi_t afi, safi_t safi, int peertype, + uint16_t maxpaths, bool same_clusterlen) +{ + if (!bgp || (afi >= AFI_MAX) || (safi >= SAFI_MAX)) + return -1; + + switch (peertype) { + case BGP_PEER_IBGP: + bgp->maxpaths[afi][safi].maxpaths_ibgp = maxpaths; + bgp->maxpaths[afi][safi].same_clusterlen = same_clusterlen; + break; + case BGP_PEER_EBGP: + bgp->maxpaths[afi][safi].maxpaths_ebgp = maxpaths; + break; + default: + return -1; + } + + return 0; +} + +/* + * bgp_maximum_paths_unset + * + * Remove maximum-paths configuration from BGP instance + */ +int bgp_maximum_paths_unset(struct bgp *bgp, afi_t afi, safi_t safi, + int peertype) +{ + if (!bgp || (afi >= AFI_MAX) || (safi >= SAFI_MAX)) + return -1; + + switch (peertype) { + case BGP_PEER_IBGP: + bgp->maxpaths[afi][safi].maxpaths_ibgp = multipath_num; + bgp->maxpaths[afi][safi].same_clusterlen = false; + break; + case BGP_PEER_EBGP: + bgp->maxpaths[afi][safi].maxpaths_ebgp = multipath_num; + break; + default: + return -1; + } + + return 0; +} + +/* + * bgp_interface_same + * + * Return true if ifindex for ifp1 and ifp2 are the same, else return false. + */ +static int bgp_interface_same(struct interface *ifp1, struct interface *ifp2) +{ + if (!ifp1 && !ifp2) + return 1; + + if (!ifp1 && ifp2) + return 0; + + if (ifp1 && !ifp2) + return 0; + + return (ifp1->ifindex == ifp2->ifindex); +} + + +/* + * bgp_path_info_nexthop_cmp + * + * Compare the nexthops of two paths. Return value is less than, equal to, + * or greater than zero if bpi1 is respectively less than, equal to, + * or greater than bpi2. + */ +int bgp_path_info_nexthop_cmp(struct bgp_path_info *bpi1, + struct bgp_path_info *bpi2) +{ + int compare; + struct in6_addr addr1, addr2; + + compare = IPV4_ADDR_CMP(&bpi1->attr->nexthop, &bpi2->attr->nexthop); + if (!compare) { + if (bpi1->attr->mp_nexthop_len == bpi2->attr->mp_nexthop_len) { + switch (bpi1->attr->mp_nexthop_len) { + case BGP_ATTR_NHLEN_IPV4: + case BGP_ATTR_NHLEN_VPNV4: + compare = IPV4_ADDR_CMP( + &bpi1->attr->mp_nexthop_global_in, + &bpi2->attr->mp_nexthop_global_in); + break; + case BGP_ATTR_NHLEN_IPV6_GLOBAL: + case BGP_ATTR_NHLEN_VPNV6_GLOBAL: + compare = IPV6_ADDR_CMP( + &bpi1->attr->mp_nexthop_global, + &bpi2->attr->mp_nexthop_global); + break; + case BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL: + addr1 = (bpi1->attr->mp_nexthop_prefer_global) + ? bpi1->attr->mp_nexthop_global + : bpi1->attr->mp_nexthop_local; + addr2 = (bpi2->attr->mp_nexthop_prefer_global) + ? bpi2->attr->mp_nexthop_global + : bpi2->attr->mp_nexthop_local; + + if (!bpi1->attr->mp_nexthop_prefer_global + && !bpi2->attr->mp_nexthop_prefer_global) + compare = !bgp_interface_same( + bpi1->peer->ifp, + bpi2->peer->ifp); + + if (!compare) + compare = IPV6_ADDR_CMP(&addr1, &addr2); + break; + } + } + + /* This can happen if one IPv6 peer sends you global and + * link-local + * nexthops but another IPv6 peer only sends you global + */ + else if (bpi1->attr->mp_nexthop_len + == BGP_ATTR_NHLEN_IPV6_GLOBAL + || bpi1->attr->mp_nexthop_len + == BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL) { + compare = IPV6_ADDR_CMP(&bpi1->attr->mp_nexthop_global, + &bpi2->attr->mp_nexthop_global); + if (!compare) { + if (bpi1->attr->mp_nexthop_len + < bpi2->attr->mp_nexthop_len) + compare = -1; + else + compare = 1; + } + } + } + + /* + * If both nexthops are same then check + * if they belong to same VRF + */ + if (!compare && bpi1->attr->nh_type != NEXTHOP_TYPE_BLACKHOLE) { + if (bpi1->extra && bpi1->extra->bgp_orig && bpi2->extra + && bpi2->extra->bgp_orig) { + if (bpi1->extra->bgp_orig->vrf_id + != bpi2->extra->bgp_orig->vrf_id) { + compare = 1; + } + } + } + + return compare; +} + +/* + * bgp_path_info_mpath_cmp + * + * This function determines our multipath list ordering. By ordering + * the list we can deterministically select which paths are included + * in the multipath set. The ordering also helps in detecting changes + * in the multipath selection so we can detect whether to send an + * update to zebra. + * + * The order of paths is determined first by received nexthop, and then + * by peer address if the nexthops are the same. + */ +static int bgp_path_info_mpath_cmp(void *val1, void *val2) +{ + struct bgp_path_info *bpi1, *bpi2; + int compare; + + bpi1 = val1; + bpi2 = val2; + + compare = bgp_path_info_nexthop_cmp(bpi1, bpi2); + + if (!compare) { + if (!bpi1->peer->su_remote && !bpi2->peer->su_remote) + compare = 0; + else if (!bpi1->peer->su_remote) + compare = 1; + else if (!bpi2->peer->su_remote) + compare = -1; + else + compare = sockunion_cmp(bpi1->peer->su_remote, + bpi2->peer->su_remote); + } + + return compare; +} + +/* + * bgp_mp_list_init + * + * Initialize the mp_list, which holds the list of multipaths + * selected by bgp_best_selection + */ +void bgp_mp_list_init(struct list *mp_list) +{ + assert(mp_list); + memset(mp_list, 0, sizeof(struct list)); + mp_list->cmp = bgp_path_info_mpath_cmp; +} + +/* + * bgp_mp_list_clear + * + * Clears all entries out of the mp_list + */ +void bgp_mp_list_clear(struct list *mp_list) +{ + assert(mp_list); + list_delete_all_node(mp_list); +} + +/* + * bgp_mp_list_add + * + * Adds a multipath entry to the mp_list + */ +void bgp_mp_list_add(struct list *mp_list, struct bgp_path_info *mpinfo) +{ + assert(mp_list && mpinfo); + listnode_add_sort(mp_list, mpinfo); +} + +/* + * bgp_path_info_mpath_new + * + * Allocate and zero memory for a new bgp_path_info_mpath element + */ +static struct bgp_path_info_mpath *bgp_path_info_mpath_new(void) +{ + struct bgp_path_info_mpath *new_mpath; + new_mpath = XCALLOC(MTYPE_BGP_MPATH_INFO, + sizeof(struct bgp_path_info_mpath)); + return new_mpath; +} + +/* + * bgp_path_info_mpath_free + * + * Release resources for a bgp_path_info_mpath element and zero out pointer + */ +void bgp_path_info_mpath_free(struct bgp_path_info_mpath **mpath) +{ + if (mpath && *mpath) { + if ((*mpath)->mp_attr) + bgp_attr_unintern(&(*mpath)->mp_attr); + XFREE(MTYPE_BGP_MPATH_INFO, *mpath); + } +} + +/* + * bgp_path_info_mpath_get + * + * Fetch the mpath element for the given bgp_path_info. Used for + * doing lazy allocation. + */ +static struct bgp_path_info_mpath * +bgp_path_info_mpath_get(struct bgp_path_info *path) +{ + struct bgp_path_info_mpath *mpath; + + if (!path) + return NULL; + + if (!path->mpath) { + mpath = bgp_path_info_mpath_new(); + if (!mpath) + return NULL; + path->mpath = mpath; + mpath->mp_info = path; + } + return path->mpath; +} + +/* + * bgp_path_info_mpath_enqueue + * + * Enqueue a path onto the multipath list given the previous multipath + * list entry + */ +static void bgp_path_info_mpath_enqueue(struct bgp_path_info *prev_info, + struct bgp_path_info *path) +{ + struct bgp_path_info_mpath *prev, *mpath; + + prev = bgp_path_info_mpath_get(prev_info); + mpath = bgp_path_info_mpath_get(path); + if (!prev || !mpath) + return; + + mpath->mp_next = prev->mp_next; + mpath->mp_prev = prev; + if (prev->mp_next) + prev->mp_next->mp_prev = mpath; + prev->mp_next = mpath; + + SET_FLAG(path->flags, BGP_PATH_MULTIPATH); +} + +/* + * bgp_path_info_mpath_dequeue + * + * Remove a path from the multipath list + */ +void bgp_path_info_mpath_dequeue(struct bgp_path_info *path) +{ + struct bgp_path_info_mpath *mpath = path->mpath; + if (!mpath) + return; + if (mpath->mp_prev) + mpath->mp_prev->mp_next = mpath->mp_next; + if (mpath->mp_next) + mpath->mp_next->mp_prev = mpath->mp_prev; + mpath->mp_next = mpath->mp_prev = NULL; + UNSET_FLAG(path->flags, BGP_PATH_MULTIPATH); +} + +/* + * bgp_path_info_mpath_next + * + * Given a bgp_path_info, return the next multipath entry + */ +struct bgp_path_info *bgp_path_info_mpath_next(struct bgp_path_info *path) +{ + if (!path->mpath || !path->mpath->mp_next) + return NULL; + return path->mpath->mp_next->mp_info; +} + +/* + * bgp_path_info_mpath_first + * + * Given bestpath bgp_path_info, return the first multipath entry. + */ +struct bgp_path_info *bgp_path_info_mpath_first(struct bgp_path_info *path) +{ + return bgp_path_info_mpath_next(path); +} + +/* + * bgp_path_info_mpath_count + * + * Given the bestpath bgp_path_info, return the number of multipath entries + */ +uint32_t bgp_path_info_mpath_count(struct bgp_path_info *path) +{ + if (!path->mpath) + return 0; + return path->mpath->mp_count; +} + +/* + * bgp_path_info_mpath_count_set + * + * Sets the count of multipaths into bestpath's mpath element + */ +static void bgp_path_info_mpath_count_set(struct bgp_path_info *path, + uint16_t count) +{ + struct bgp_path_info_mpath *mpath; + if (!count && !path->mpath) + return; + mpath = bgp_path_info_mpath_get(path); + if (!mpath) + return; + mpath->mp_count = count; +} + +/* + * bgp_path_info_mpath_lb_update + * + * Update cumulative info related to link-bandwidth + */ +static void bgp_path_info_mpath_lb_update(struct bgp_path_info *path, bool set, + bool all_paths_lb, uint64_t cum_bw) +{ + struct bgp_path_info_mpath *mpath; + + mpath = path->mpath; + if (mpath == NULL) { + if (!set || (cum_bw == 0 && !all_paths_lb)) + return; + + mpath = bgp_path_info_mpath_get(path); + if (!mpath) + return; + } + if (set) { + if (cum_bw) + SET_FLAG(mpath->mp_flags, BGP_MP_LB_PRESENT); + else + UNSET_FLAG(mpath->mp_flags, BGP_MP_LB_PRESENT); + if (all_paths_lb) + SET_FLAG(mpath->mp_flags, BGP_MP_LB_ALL); + else + UNSET_FLAG(mpath->mp_flags, BGP_MP_LB_ALL); + mpath->cum_bw = cum_bw; + } else { + mpath->mp_flags = 0; + mpath->cum_bw = 0; + } +} + +/* + * bgp_path_info_mpath_attr + * + * Given bestpath bgp_path_info, return aggregated attribute set used + * for advertising the multipath route + */ +struct attr *bgp_path_info_mpath_attr(struct bgp_path_info *path) +{ + if (!path->mpath) + return NULL; + return path->mpath->mp_attr; +} + +/* + * bgp_path_info_chkwtd + * + * Return if we should attempt to do weighted ECMP or not + * The path passed in is the bestpath. + */ +bool bgp_path_info_mpath_chkwtd(struct bgp *bgp, struct bgp_path_info *path) +{ + /* Check if told to ignore weights or not multipath */ + if (bgp->lb_handling == BGP_LINK_BW_IGNORE_BW || !path->mpath) + return false; + + /* All paths in multipath should have associated weight (bandwidth) + * unless told explicitly otherwise. + */ + if (bgp->lb_handling != BGP_LINK_BW_SKIP_MISSING && + bgp->lb_handling != BGP_LINK_BW_DEFWT_4_MISSING) + return (path->mpath->mp_flags & BGP_MP_LB_ALL); + + /* At least one path should have bandwidth. */ + return (path->mpath->mp_flags & BGP_MP_LB_PRESENT); +} + +/* + * bgp_path_info_mpath_attr + * + * Given bestpath bgp_path_info, return cumulative bandwidth + * computed for all multipaths with bandwidth info + */ +uint64_t bgp_path_info_mpath_cumbw(struct bgp_path_info *path) +{ + if (!path->mpath) + return 0; + return path->mpath->cum_bw; +} + +/* + * bgp_path_info_mpath_attr_set + * + * Sets the aggregated attribute into bestpath's mpath element + */ +static void bgp_path_info_mpath_attr_set(struct bgp_path_info *path, + struct attr *attr) +{ + struct bgp_path_info_mpath *mpath; + if (!attr && !path->mpath) + return; + mpath = bgp_path_info_mpath_get(path); + if (!mpath) + return; + mpath->mp_attr = attr; +} + +/* + * bgp_path_info_mpath_update + * + * Compare and sync up the multipath list with the mp_list generated by + * bgp_best_selection + */ +void bgp_path_info_mpath_update(struct bgp *bgp, struct bgp_dest *dest, + struct bgp_path_info *new_best, + struct bgp_path_info *old_best, + struct list *mp_list, + struct bgp_maxpaths_cfg *mpath_cfg) +{ + uint16_t maxpaths, mpath_count, old_mpath_count; + uint32_t bwval; + uint64_t cum_bw, old_cum_bw; + struct listnode *mp_node, *mp_next_node; + struct bgp_path_info *cur_mpath, *new_mpath, *next_mpath, *prev_mpath; + int mpath_changed, debug; + bool all_paths_lb; + char path_buf[PATH_ADDPATH_STR_BUFFER]; + + mpath_changed = 0; + maxpaths = multipath_num; + mpath_count = 0; + cur_mpath = NULL; + old_mpath_count = 0; + old_cum_bw = cum_bw = 0; + prev_mpath = new_best; + mp_node = listhead(mp_list); + debug = bgp_debug_bestpath(dest); + + if (new_best) { + mpath_count++; + if (new_best != old_best) + bgp_path_info_mpath_dequeue(new_best); + maxpaths = (new_best->peer->sort == BGP_PEER_IBGP) + ? mpath_cfg->maxpaths_ibgp + : mpath_cfg->maxpaths_ebgp; + } + + if (old_best) { + cur_mpath = bgp_path_info_mpath_first(old_best); + old_mpath_count = bgp_path_info_mpath_count(old_best); + old_cum_bw = bgp_path_info_mpath_cumbw(old_best); + bgp_path_info_mpath_count_set(old_best, 0); + bgp_path_info_mpath_lb_update(old_best, false, false, 0); + bgp_path_info_mpath_dequeue(old_best); + } + + if (debug) + zlog_debug( + "%pRN(%s): starting mpath update, newbest %s num candidates %d old-mpath-count %d old-cum-bw u%" PRIu64, + bgp_dest_to_rnode(dest), bgp->name_pretty, + new_best ? new_best->peer->host : "NONE", + mp_list ? listcount(mp_list) : 0, old_mpath_count, + old_cum_bw); + + /* + * We perform an ordered walk through both lists in parallel. + * The reason for the ordered walk is that if there are paths + * that were previously multipaths and are still multipaths, the walk + * should encounter them in both lists at the same time. Otherwise + * there will be paths that are in one list or another, and we + * will deal with these separately. + * + * Note that new_best might be somewhere in the mp_list, so we need + * to skip over it + */ + all_paths_lb = true; /* We'll reset if any path doesn't have LB. */ + while (mp_node || cur_mpath) { + struct bgp_path_info *tmp_info; + + /* + * We can bail out of this loop if all existing paths on the + * multipath list have been visited (for cleanup purposes) and + * the maxpath requirement is fulfulled + */ + if (!cur_mpath && (mpath_count >= maxpaths)) + break; + + mp_next_node = mp_node ? listnextnode(mp_node) : NULL; + next_mpath = + cur_mpath ? bgp_path_info_mpath_next(cur_mpath) : NULL; + tmp_info = mp_node ? listgetdata(mp_node) : NULL; + + if (debug) + zlog_debug( + "%pRN(%s): comparing candidate %s with existing mpath %s", + bgp_dest_to_rnode(dest), bgp->name_pretty, + tmp_info ? tmp_info->peer->host : "NONE", + cur_mpath ? cur_mpath->peer->host : "NONE"); + + /* + * If equal, the path was a multipath and is still a multipath. + * Insert onto new multipath list if maxpaths allows. + */ + if (mp_node && (listgetdata(mp_node) == cur_mpath)) { + list_delete_node(mp_list, mp_node); + bgp_path_info_mpath_dequeue(cur_mpath); + if ((mpath_count < maxpaths) + && prev_mpath + && bgp_path_info_nexthop_cmp(prev_mpath, + cur_mpath)) { + bgp_path_info_mpath_enqueue(prev_mpath, + cur_mpath); + prev_mpath = cur_mpath; + mpath_count++; + if (ecommunity_linkbw_present( + bgp_attr_get_ecommunity( + cur_mpath->attr), + &bwval)) + cum_bw += bwval; + else + all_paths_lb = false; + if (debug) { + bgp_path_info_path_with_addpath_rx_str( + cur_mpath, path_buf, + sizeof(path_buf)); + zlog_debug( + "%pRN: %s is still multipath, cur count %d", + bgp_dest_to_rnode(dest), + path_buf, mpath_count); + } + } else { + mpath_changed = 1; + if (debug) { + bgp_path_info_path_with_addpath_rx_str( + cur_mpath, path_buf, + sizeof(path_buf)); + zlog_debug( + "%pRN: remove mpath %s nexthop %pI4, cur count %d", + bgp_dest_to_rnode(dest), + path_buf, + &cur_mpath->attr->nexthop, + mpath_count); + } + } + mp_node = mp_next_node; + cur_mpath = next_mpath; + continue; + } + + if (cur_mpath + && (!mp_node + || (bgp_path_info_mpath_cmp(cur_mpath, + listgetdata(mp_node)) + < 0))) { + /* + * If here, we have an old multipath and either the + * mp_list + * is finished or the next mp_node points to a later + * multipath, so we need to purge this path from the + * multipath list + */ + bgp_path_info_mpath_dequeue(cur_mpath); + mpath_changed = 1; + if (debug) { + bgp_path_info_path_with_addpath_rx_str( + cur_mpath, path_buf, sizeof(path_buf)); + zlog_debug( + "%pRN: remove mpath %s nexthop %pI4, cur count %d", + bgp_dest_to_rnode(dest), path_buf, + &cur_mpath->attr->nexthop, mpath_count); + } + cur_mpath = next_mpath; + } else { + /* + * If here, we have a path on the mp_list that was not + * previously + * a multipath (due to non-equivalance or maxpaths + * exceeded), + * or the matching multipath is sorted later in the + * multipath + * list. Before we enqueue the path on the new multipath + * list, + * make sure its not on the old_best multipath list or + * referenced + * via next_mpath: + * - If next_mpath points to this new path, update + * next_mpath to + * point to the multipath after this one + * - Dequeue the path from the multipath list just to + * make sure + */ + new_mpath = listgetdata(mp_node); + list_delete_node(mp_list, mp_node); + assert(new_mpath); + assert(prev_mpath); + if ((mpath_count < maxpaths) && (new_mpath != new_best) + && bgp_path_info_nexthop_cmp(prev_mpath, + new_mpath)) { + bgp_path_info_mpath_dequeue(new_mpath); + + bgp_path_info_mpath_enqueue(prev_mpath, + new_mpath); + prev_mpath = new_mpath; + mpath_changed = 1; + mpath_count++; + if (ecommunity_linkbw_present( + bgp_attr_get_ecommunity( + new_mpath->attr), + &bwval)) + cum_bw += bwval; + else + all_paths_lb = false; + if (debug) { + bgp_path_info_path_with_addpath_rx_str( + new_mpath, path_buf, + sizeof(path_buf)); + zlog_debug( + "%pRN: add mpath %s nexthop %pI4, cur count %d", + bgp_dest_to_rnode(dest), + path_buf, + &new_mpath->attr->nexthop, + mpath_count); + } + } + mp_node = mp_next_node; + } + } + + if (new_best) { + bgp_path_info_mpath_count_set(new_best, mpath_count - 1); + if (mpath_count <= 1 || + !ecommunity_linkbw_present( + bgp_attr_get_ecommunity(new_best->attr), &bwval)) + all_paths_lb = false; + else + cum_bw += bwval; + bgp_path_info_mpath_lb_update(new_best, true, + all_paths_lb, cum_bw); + + if (debug) + zlog_debug( + "%pRN(%s): New mpath count (incl newbest) %d mpath-change %s all_paths_lb %d cum_bw u%" PRIu64, + bgp_dest_to_rnode(dest), bgp->name_pretty, + mpath_count, mpath_changed ? "YES" : "NO", + all_paths_lb, cum_bw); + + if (mpath_changed + || (bgp_path_info_mpath_count(new_best) != old_mpath_count)) + SET_FLAG(new_best->flags, BGP_PATH_MULTIPATH_CHG); + if ((mpath_count - 1) != old_mpath_count || + old_cum_bw != cum_bw) + SET_FLAG(new_best->flags, BGP_PATH_LINK_BW_CHG); + } +} + +/* + * bgp_mp_dmed_deselect + * + * Clean up multipath information for BGP_PATH_DMED_SELECTED path that + * is not selected as best path + */ +void bgp_mp_dmed_deselect(struct bgp_path_info *dmed_best) +{ + struct bgp_path_info *mpinfo, *mpnext; + + if (!dmed_best) + return; + + for (mpinfo = bgp_path_info_mpath_first(dmed_best); mpinfo; + mpinfo = mpnext) { + mpnext = bgp_path_info_mpath_next(mpinfo); + bgp_path_info_mpath_dequeue(mpinfo); + } + + bgp_path_info_mpath_count_set(dmed_best, 0); + UNSET_FLAG(dmed_best->flags, BGP_PATH_MULTIPATH_CHG); + UNSET_FLAG(dmed_best->flags, BGP_PATH_LINK_BW_CHG); + assert(bgp_path_info_mpath_first(dmed_best) == NULL); +} + +/* + * bgp_path_info_mpath_aggregate_update + * + * Set the multipath aggregate attribute. We need to see if the + * aggregate has changed and then set the ATTR_CHANGED flag on the + * bestpath info so that a peer update will be generated. The + * change is detected by generating the current attribute, + * interning it, and then comparing the interned pointer with the + * current value. We can skip this generate/compare step if there + * is no change in multipath selection and no attribute change in + * any multipath. + */ +void bgp_path_info_mpath_aggregate_update(struct bgp_path_info *new_best, + struct bgp_path_info *old_best) +{ + struct bgp_path_info *mpinfo; + struct aspath *aspath; + struct aspath *asmerge; + struct attr *new_attr, *old_attr; + uint8_t origin; + struct community *community, *commerge; + struct ecommunity *ecomm, *ecommerge; + struct lcommunity *lcomm, *lcommerge; + struct attr attr = {0}; + + if (old_best && (old_best != new_best) + && (old_attr = bgp_path_info_mpath_attr(old_best))) { + bgp_attr_unintern(&old_attr); + bgp_path_info_mpath_attr_set(old_best, NULL); + } + + if (!new_best) + return; + + if (!bgp_path_info_mpath_count(new_best)) { + if ((new_attr = bgp_path_info_mpath_attr(new_best))) { + bgp_attr_unintern(&new_attr); + bgp_path_info_mpath_attr_set(new_best, NULL); + SET_FLAG(new_best->flags, BGP_PATH_ATTR_CHANGED); + } + return; + } + + attr = *new_best->attr; + + if (new_best->peer + && CHECK_FLAG(new_best->peer->bgp->flags, + BGP_FLAG_MULTIPATH_RELAX_AS_SET)) { + + /* aggregate attribute from multipath constituents */ + aspath = aspath_dup(attr.aspath); + origin = attr.origin; + community = + bgp_attr_get_community(&attr) + ? community_dup(bgp_attr_get_community(&attr)) + : NULL; + ecomm = (bgp_attr_get_ecommunity(&attr)) + ? ecommunity_dup(bgp_attr_get_ecommunity(&attr)) + : NULL; + lcomm = (bgp_attr_get_lcommunity(&attr)) + ? lcommunity_dup(bgp_attr_get_lcommunity(&attr)) + : NULL; + + for (mpinfo = bgp_path_info_mpath_first(new_best); mpinfo; + mpinfo = bgp_path_info_mpath_next(mpinfo)) { + asmerge = + aspath_aggregate(aspath, mpinfo->attr->aspath); + aspath_free(aspath); + aspath = asmerge; + + if (origin < mpinfo->attr->origin) + origin = mpinfo->attr->origin; + + if (bgp_attr_get_community(mpinfo->attr)) { + if (community) { + commerge = community_merge( + community, + bgp_attr_get_community( + mpinfo->attr)); + community = + community_uniq_sort(commerge); + community_free(&commerge); + } else + community = community_dup( + bgp_attr_get_community( + mpinfo->attr)); + } + + if (bgp_attr_get_ecommunity(mpinfo->attr)) { + if (ecomm) { + ecommerge = ecommunity_merge( + ecomm, bgp_attr_get_ecommunity( + mpinfo->attr)); + ecomm = ecommunity_uniq_sort(ecommerge); + ecommunity_free(&ecommerge); + } else + ecomm = ecommunity_dup( + bgp_attr_get_ecommunity( + mpinfo->attr)); + } + if (bgp_attr_get_lcommunity(mpinfo->attr)) { + if (lcomm) { + lcommerge = lcommunity_merge( + lcomm, bgp_attr_get_lcommunity( + mpinfo->attr)); + lcomm = lcommunity_uniq_sort(lcommerge); + lcommunity_free(&lcommerge); + } else + lcomm = lcommunity_dup( + bgp_attr_get_lcommunity( + mpinfo->attr)); + } + } + + attr.aspath = aspath; + attr.origin = origin; + if (community) + bgp_attr_set_community(&attr, community); + if (ecomm) + bgp_attr_set_ecommunity(&attr, ecomm); + if (lcomm) + bgp_attr_set_lcommunity(&attr, lcomm); + + /* Zap multipath attr nexthop so we set nexthop to self */ + attr.nexthop.s_addr = INADDR_ANY; + memset(&attr.mp_nexthop_global, 0, sizeof(struct in6_addr)); + + /* TODO: should we set ATOMIC_AGGREGATE and AGGREGATOR? */ + } + + new_attr = bgp_attr_intern(&attr); + + if (new_attr != bgp_path_info_mpath_attr(new_best)) { + if ((old_attr = bgp_path_info_mpath_attr(new_best))) + bgp_attr_unintern(&old_attr); + bgp_path_info_mpath_attr_set(new_best, new_attr); + SET_FLAG(new_best->flags, BGP_PATH_ATTR_CHANGED); + } else + bgp_attr_unintern(&new_attr); +} |