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bgp_route.c
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bgp_route.c
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/* BGP routing information
* Copyright (C) 1996, 97, 98, 99 Kunihiro Ishiguro
* Copyright (C) 2016 Job Snijders <job@instituut.net>
*
* 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 <math.h>
#include "prefix.h"
#include "linklist.h"
#include "memory.h"
#include "command.h"
#include "stream.h"
#include "filter.h"
#include "log.h"
#include "routemap.h"
#include "buffer.h"
#include "sockunion.h"
#include "plist.h"
#include "thread.h"
#include "workqueue.h"
#include "queue.h"
#include "memory.h"
#include "lib/json.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_regex.h"
#include "bgpd/bgp_community.h"
#include "bgpd/bgp_ecommunity.h"
#include "bgpd/bgp_lcommunity.h"
#include "bgpd/bgp_clist.h"
#include "bgpd/bgp_packet.h"
#include "bgpd/bgp_filter.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_mplsvpn.h"
#include "bgpd/bgp_nexthop.h"
#include "bgpd/bgp_damp.h"
#include "bgpd/bgp_advertise.h"
#include "bgpd/bgp_zebra.h"
#include "bgpd/bgp_vty.h"
#include "bgpd/bgp_mpath.h"
#include "bgpd/bgp_nht.h"
#include "bgpd/bgp_updgrp.h"
#include "bgpd/bgp_label.h"
#if ENABLE_BGP_VNC
#include "bgpd/rfapi/rfapi_backend.h"
#include "bgpd/rfapi/vnc_import_bgp.h"
#include "bgpd/rfapi/vnc_export_bgp.h"
#endif
#include "bgpd/bgp_encap_types.h"
#include "bgpd/bgp_encap_tlv.h"
#include "bgpd/bgp_evpn.h"
#include "bgpd/bgp_evpn_vty.h"
#include "bgpd/bgp_flowspec.h"
#include "bgpd/bgp_flowspec_util.h"
#include "bgpd/bgp_pbr.h"
#ifndef VTYSH_EXTRACT_PL
#include "bgpd/bgp_route_clippy.c"
#endif
/* Extern from bgp_dump.c */
extern const char *bgp_origin_str[];
extern const char *bgp_origin_long_str[];
/* PMSI strings. */
#define PMSI_TNLTYPE_STR_NO_INFO "No info"
#define PMSI_TNLTYPE_STR_DEFAULT PMSI_TNLTYPE_STR_NO_INFO
static const struct message bgp_pmsi_tnltype_str[] = {
{PMSI_TNLTYPE_NO_INFO, PMSI_TNLTYPE_STR_NO_INFO},
{PMSI_TNLTYPE_RSVP_TE_P2MP, "RSVP-TE P2MP"},
{PMSI_TNLTYPE_MLDP_P2MP, "mLDP P2MP"},
{PMSI_TNLTYPE_PIM_SSM, "PIM-SSM"},
{PMSI_TNLTYPE_PIM_SM, "PIM-SM"},
{PMSI_TNLTYPE_PIM_BIDIR, "PIM-BIDIR"},
{PMSI_TNLTYPE_INGR_REPL, "Ingress Replication"},
{PMSI_TNLTYPE_MLDP_MP2MP, "mLDP MP2MP"},
{0}
};
#define VRFID_NONE_STR "-"
struct bgp_node *bgp_afi_node_get(struct bgp_table *table, afi_t afi,
safi_t safi, struct prefix *p,
struct prefix_rd *prd)
{
struct bgp_node *rn;
struct bgp_node *prn = NULL;
assert(table);
if (!table)
return NULL;
if ((safi == SAFI_MPLS_VPN) || (safi == SAFI_ENCAP)
|| (safi == SAFI_EVPN)) {
prn = bgp_node_get(table, (struct prefix *)prd);
if (prn->info == NULL)
prn->info = bgp_table_init(table->bgp, afi, safi);
else
bgp_unlock_node(prn);
table = prn->info;
}
rn = bgp_node_get(table, p);
if ((safi == SAFI_MPLS_VPN) || (safi == SAFI_ENCAP)
|| (safi == SAFI_EVPN))
rn->prn = prn;
return rn;
}
struct bgp_node *bgp_afi_node_lookup(struct bgp_table *table, afi_t afi,
safi_t safi, struct prefix *p,
struct prefix_rd *prd)
{
struct bgp_node *rn;
struct bgp_node *prn = NULL;
if (!table)
return NULL;
if ((safi == SAFI_MPLS_VPN) || (safi == SAFI_ENCAP)
|| (safi == SAFI_EVPN)) {
prn = bgp_node_lookup(table, (struct prefix *)prd);
if (!prn)
return NULL;
if (prn->info == NULL) {
bgp_unlock_node(prn);
return NULL;
}
table = prn->info;
}
rn = bgp_node_lookup(table, p);
return rn;
}
/* Allocate bgp_info_extra */
static struct bgp_info_extra *bgp_info_extra_new(void)
{
struct bgp_info_extra *new;
new = XCALLOC(MTYPE_BGP_ROUTE_EXTRA, sizeof(struct bgp_info_extra));
new->label[0] = MPLS_INVALID_LABEL;
new->num_labels = 0;
return new;
}
static void bgp_info_extra_free(struct bgp_info_extra **extra)
{
if (extra && *extra) {
if ((*extra)->damp_info)
bgp_damp_info_free((*extra)->damp_info, 0);
(*extra)->damp_info = NULL;
XFREE(MTYPE_BGP_ROUTE_EXTRA, *extra);
*extra = NULL;
}
}
/* Get bgp_info extra information for the given bgp_info, lazy allocated
* if required.
*/
struct bgp_info_extra *bgp_info_extra_get(struct bgp_info *ri)
{
if (!ri->extra)
ri->extra = bgp_info_extra_new();
return ri->extra;
}
/* Allocate new bgp info structure. */
struct bgp_info *bgp_info_new(void)
{
return XCALLOC(MTYPE_BGP_ROUTE, sizeof(struct bgp_info));
}
/* Free bgp route information. */
static void bgp_info_free(struct bgp_info *binfo)
{
if (binfo->attr)
bgp_attr_unintern(&binfo->attr);
bgp_unlink_nexthop(binfo);
bgp_info_extra_free(&binfo->extra);
bgp_info_mpath_free(&binfo->mpath);
peer_unlock(binfo->peer); /* bgp_info peer reference */
XFREE(MTYPE_BGP_ROUTE, binfo);
}
struct bgp_info *bgp_info_lock(struct bgp_info *binfo)
{
binfo->lock++;
return binfo;
}
struct bgp_info *bgp_info_unlock(struct bgp_info *binfo)
{
/* unlink reference to parent, if any. */
if (binfo->extra && binfo->extra->parent) {
bgp_info_unlock((struct bgp_info *)binfo->extra->parent);
binfo->extra->parent = NULL;
}
assert(binfo && binfo->lock > 0);
binfo->lock--;
if (binfo->lock == 0) {
#if 0
zlog_debug ("%s: unlocked and freeing", __func__);
zlog_backtrace (LOG_DEBUG);
#endif
bgp_info_free(binfo);
return NULL;
}
#if 0
if (binfo->lock == 1)
{
zlog_debug ("%s: unlocked to 1", __func__);
zlog_backtrace (LOG_DEBUG);
}
#endif
return binfo;
}
void bgp_info_add(struct bgp_node *rn, struct bgp_info *ri)
{
struct bgp_info *top;
top = rn->info;
ri->next = rn->info;
ri->prev = NULL;
if (top)
top->prev = ri;
rn->info = ri;
bgp_info_lock(ri);
bgp_lock_node(rn);
peer_lock(ri->peer); /* bgp_info peer reference */
}
/* Do the actual removal of info from RIB, for use by bgp_process
completion callback *only* */
void bgp_info_reap(struct bgp_node *rn, struct bgp_info *ri)
{
if (ri->next)
ri->next->prev = ri->prev;
if (ri->prev)
ri->prev->next = ri->next;
else
rn->info = ri->next;
bgp_info_mpath_dequeue(ri);
bgp_info_unlock(ri);
bgp_unlock_node(rn);
}
void bgp_info_delete(struct bgp_node *rn, struct bgp_info *ri)
{
bgp_info_set_flag(rn, ri, BGP_INFO_REMOVED);
/* set of previous already took care of pcount */
UNSET_FLAG(ri->flags, BGP_INFO_VALID);
}
/* undo the effects of a previous call to bgp_info_delete; typically
called when a route is deleted and then quickly re-added before the
deletion has been processed */
void bgp_info_restore(struct bgp_node *rn, struct bgp_info *ri)
{
bgp_info_unset_flag(rn, ri, BGP_INFO_REMOVED);
/* unset of previous already took care of pcount */
SET_FLAG(ri->flags, BGP_INFO_VALID);
}
/* Adjust pcount as required */
static void bgp_pcount_adjust(struct bgp_node *rn, struct bgp_info *ri)
{
struct bgp_table *table;
assert(rn && bgp_node_table(rn));
assert(ri && ri->peer && ri->peer->bgp);
table = bgp_node_table(rn);
if (ri->peer == ri->peer->bgp->peer_self)
return;
if (!BGP_INFO_COUNTABLE(ri)
&& CHECK_FLAG(ri->flags, BGP_INFO_COUNTED)) {
UNSET_FLAG(ri->flags, BGP_INFO_COUNTED);
/* slight hack, but more robust against errors. */
if (ri->peer->pcount[table->afi][table->safi])
ri->peer->pcount[table->afi][table->safi]--;
else {
zlog_warn(
"%s: Asked to decrement 0 prefix count for peer %s",
__func__, ri->peer->host);
zlog_backtrace(LOG_WARNING);
zlog_warn("%s: Please report to Quagga bugzilla",
__func__);
}
} else if (BGP_INFO_COUNTABLE(ri)
&& !CHECK_FLAG(ri->flags, BGP_INFO_COUNTED)) {
SET_FLAG(ri->flags, BGP_INFO_COUNTED);
ri->peer->pcount[table->afi][table->safi]++;
}
}
static int bgp_label_index_differs(struct bgp_info *ri1, struct bgp_info *ri2)
{
return (!(ri1->attr->label_index == ri2->attr->label_index));
}
/* Set/unset bgp_info flags, adjusting any other state as needed.
* This is here primarily to keep prefix-count in check.
*/
void bgp_info_set_flag(struct bgp_node *rn, struct bgp_info *ri, uint32_t flag)
{
SET_FLAG(ri->flags, flag);
/* early bath if we know it's not a flag that changes countability state
*/
if (!CHECK_FLAG(flag,
BGP_INFO_VALID | BGP_INFO_HISTORY | BGP_INFO_REMOVED))
return;
bgp_pcount_adjust(rn, ri);
}
void bgp_info_unset_flag(struct bgp_node *rn, struct bgp_info *ri,
uint32_t flag)
{
UNSET_FLAG(ri->flags, flag);
/* early bath if we know it's not a flag that changes countability state
*/
if (!CHECK_FLAG(flag,
BGP_INFO_VALID | BGP_INFO_HISTORY | BGP_INFO_REMOVED))
return;
bgp_pcount_adjust(rn, ri);
}
/* Get MED value. If MED value is missing and "bgp bestpath
missing-as-worst" is specified, treat it as the worst value. */
static uint32_t bgp_med_value(struct attr *attr, struct bgp *bgp)
{
if (attr->flag & ATTR_FLAG_BIT(BGP_ATTR_MULTI_EXIT_DISC))
return attr->med;
else {
if (bgp_flag_check(bgp, BGP_FLAG_MED_MISSING_AS_WORST))
return BGP_MED_MAX;
else
return 0;
}
}
void bgp_info_path_with_addpath_rx_str(struct bgp_info *ri, char *buf)
{
if (ri->addpath_rx_id)
sprintf(buf, "path %s (addpath rxid %d)", ri->peer->host,
ri->addpath_rx_id);
else
sprintf(buf, "path %s", ri->peer->host);
}
/* Compare two bgp route entity. If 'new' is preferable over 'exist' return 1.
*/
static int bgp_info_cmp(struct bgp *bgp, struct bgp_info *new,
struct bgp_info *exist, int *paths_eq,
struct bgp_maxpaths_cfg *mpath_cfg, int debug,
char *pfx_buf, afi_t afi, safi_t safi)
{
struct attr *newattr, *existattr;
bgp_peer_sort_t new_sort;
bgp_peer_sort_t exist_sort;
uint32_t new_pref;
uint32_t exist_pref;
uint32_t new_med;
uint32_t exist_med;
uint32_t new_weight;
uint32_t exist_weight;
uint32_t newm, existm;
struct in_addr new_id;
struct in_addr exist_id;
int new_cluster;
int exist_cluster;
int internal_as_route;
int confed_as_route;
int ret = 0;
char new_buf[PATH_ADDPATH_STR_BUFFER];
char exist_buf[PATH_ADDPATH_STR_BUFFER];
uint32_t new_mm_seq;
uint32_t exist_mm_seq;
*paths_eq = 0;
/* 0. Null check. */
if (new == NULL) {
if (debug)
zlog_debug("%s: new is NULL", pfx_buf);
return 0;
}
if (debug)
bgp_info_path_with_addpath_rx_str(new, new_buf);
if (exist == NULL) {
if (debug)
zlog_debug("%s: %s is the initial bestpath", pfx_buf,
new_buf);
return 1;
}
if (debug) {
bgp_info_path_with_addpath_rx_str(exist, exist_buf);
zlog_debug("%s: Comparing %s flags 0x%x with %s flags 0x%x",
pfx_buf, new_buf, new->flags, exist_buf,
exist->flags);
}
newattr = new->attr;
existattr = exist->attr;
/* For EVPN routes, we cannot just go by local vs remote, we have to
* look at the MAC mobility sequence number, if present.
*/
if (safi == SAFI_EVPN) {
/* This is an error condition described in RFC 7432 Section
* 15.2. The RFC
* states that in this scenario "the PE MUST alert the operator"
* but it
* does not state what other action to take. In order to provide
* some
* consistency in this scenario we are going to prefer the path
* with the
* sticky flag.
*/
if (newattr->sticky != existattr->sticky) {
if (!debug) {
prefix2str(&new->net->p, pfx_buf,
sizeof(*pfx_buf)
* PREFIX2STR_BUFFER);
bgp_info_path_with_addpath_rx_str(new, new_buf);
bgp_info_path_with_addpath_rx_str(exist,
exist_buf);
}
if (newattr->sticky && !existattr->sticky) {
zlog_warn(
"%s: %s wins over %s due to sticky MAC flag",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (!newattr->sticky && existattr->sticky) {
zlog_warn(
"%s: %s loses to %s due to sticky MAC flag",
pfx_buf, new_buf, exist_buf);
return 0;
}
}
new_mm_seq = mac_mobility_seqnum(newattr);
exist_mm_seq = mac_mobility_seqnum(existattr);
if (new_mm_seq > exist_mm_seq) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to MM seq %u > %u",
pfx_buf, new_buf, exist_buf, new_mm_seq,
exist_mm_seq);
return 1;
}
if (new_mm_seq < exist_mm_seq) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to MM seq %u < %u",
pfx_buf, new_buf, exist_buf, new_mm_seq,
exist_mm_seq);
return 0;
}
}
/* 1. Weight check. */
new_weight = newattr->weight;
exist_weight = existattr->weight;
if (new_weight > exist_weight) {
if (debug)
zlog_debug("%s: %s wins over %s due to weight %d > %d",
pfx_buf, new_buf, exist_buf, new_weight,
exist_weight);
return 1;
}
if (new_weight < exist_weight) {
if (debug)
zlog_debug("%s: %s loses to %s due to weight %d < %d",
pfx_buf, new_buf, exist_buf, new_weight,
exist_weight);
return 0;
}
/* 2. Local preference check. */
new_pref = exist_pref = bgp->default_local_pref;
if (newattr->flag & ATTR_FLAG_BIT(BGP_ATTR_LOCAL_PREF))
new_pref = newattr->local_pref;
if (existattr->flag & ATTR_FLAG_BIT(BGP_ATTR_LOCAL_PREF))
exist_pref = existattr->local_pref;
if (new_pref > exist_pref) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to localpref %d > %d",
pfx_buf, new_buf, exist_buf, new_pref,
exist_pref);
return 1;
}
if (new_pref < exist_pref) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to localpref %d < %d",
pfx_buf, new_buf, exist_buf, new_pref,
exist_pref);
return 0;
}
/* 3. Local route check. We prefer:
* - BGP_ROUTE_STATIC
* - BGP_ROUTE_AGGREGATE
* - BGP_ROUTE_REDISTRIBUTE
*/
if (!(new->sub_type == BGP_ROUTE_NORMAL ||
new->sub_type == BGP_ROUTE_IMPORTED)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to preferred BGP_ROUTE type",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (!(exist->sub_type == BGP_ROUTE_NORMAL ||
exist->sub_type == BGP_ROUTE_IMPORTED)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to preferred BGP_ROUTE type",
pfx_buf, new_buf, exist_buf);
return 0;
}
/* 4. AS path length check. */
if (!bgp_flag_check(bgp, BGP_FLAG_ASPATH_IGNORE)) {
int exist_hops = aspath_count_hops(existattr->aspath);
int exist_confeds = aspath_count_confeds(existattr->aspath);
if (bgp_flag_check(bgp, BGP_FLAG_ASPATH_CONFED)) {
int aspath_hops;
aspath_hops = aspath_count_hops(newattr->aspath);
aspath_hops += aspath_count_confeds(newattr->aspath);
if (aspath_hops < (exist_hops + exist_confeds)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to aspath (with confeds) hopcount %d < %d",
pfx_buf, new_buf, exist_buf,
aspath_hops,
(exist_hops + exist_confeds));
return 1;
}
if (aspath_hops > (exist_hops + exist_confeds)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to aspath (with confeds) hopcount %d > %d",
pfx_buf, new_buf, exist_buf,
aspath_hops,
(exist_hops + exist_confeds));
return 0;
}
} else {
int newhops = aspath_count_hops(newattr->aspath);
if (newhops < exist_hops) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to aspath hopcount %d < %d",
pfx_buf, new_buf, exist_buf,
newhops, exist_hops);
return 1;
}
if (newhops > exist_hops) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to aspath hopcount %d > %d",
pfx_buf, new_buf, exist_buf,
newhops, exist_hops);
return 0;
}
}
}
/* 5. Origin check. */
if (newattr->origin < existattr->origin) {
if (debug)
zlog_debug("%s: %s wins over %s due to ORIGIN %s < %s",
pfx_buf, new_buf, exist_buf,
bgp_origin_long_str[newattr->origin],
bgp_origin_long_str[existattr->origin]);
return 1;
}
if (newattr->origin > existattr->origin) {
if (debug)
zlog_debug("%s: %s loses to %s due to ORIGIN %s > %s",
pfx_buf, new_buf, exist_buf,
bgp_origin_long_str[newattr->origin],
bgp_origin_long_str[existattr->origin]);
return 0;
}
/* 6. MED check. */
internal_as_route = (aspath_count_hops(newattr->aspath) == 0
&& aspath_count_hops(existattr->aspath) == 0);
confed_as_route = (aspath_count_confeds(newattr->aspath) > 0
&& aspath_count_confeds(existattr->aspath) > 0
&& aspath_count_hops(newattr->aspath) == 0
&& aspath_count_hops(existattr->aspath) == 0);
if (bgp_flag_check(bgp, BGP_FLAG_ALWAYS_COMPARE_MED)
|| (bgp_flag_check(bgp, BGP_FLAG_MED_CONFED) && confed_as_route)
|| aspath_cmp_left(newattr->aspath, existattr->aspath)
|| aspath_cmp_left_confed(newattr->aspath, existattr->aspath)
|| internal_as_route) {
new_med = bgp_med_value(new->attr, bgp);
exist_med = bgp_med_value(exist->attr, bgp);
if (new_med < exist_med) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to MED %d < %d",
pfx_buf, new_buf, exist_buf, new_med,
exist_med);
return 1;
}
if (new_med > exist_med) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to MED %d > %d",
pfx_buf, new_buf, exist_buf, new_med,
exist_med);
return 0;
}
}
/* 7. Peer type check. */
new_sort = new->peer->sort;
exist_sort = exist->peer->sort;
if (new_sort == BGP_PEER_EBGP
&& (exist_sort == BGP_PEER_IBGP || exist_sort == BGP_PEER_CONFED)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to eBGP peer > iBGP peer",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (exist_sort == BGP_PEER_EBGP
&& (new_sort == BGP_PEER_IBGP || new_sort == BGP_PEER_CONFED)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to iBGP peer < eBGP peer",
pfx_buf, new_buf, exist_buf);
return 0;
}
/* 8. IGP metric check. */
newm = existm = 0;
if (new->extra)
newm = new->extra->igpmetric;
if (exist->extra)
existm = exist->extra->igpmetric;
if (newm < existm) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to IGP metric %d < %d",
pfx_buf, new_buf, exist_buf, newm, existm);
ret = 1;
}
if (newm > existm) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to IGP metric %d > %d",
pfx_buf, new_buf, exist_buf, newm, existm);
ret = 0;
}
/* 9. Same IGP metric. Compare the cluster list length as
representative of IGP hops metric. Rewrite the metric value
pair (newm, existm) with the cluster list length. Prefer the
path with smaller cluster list length. */
if (newm == existm) {
if (peer_sort(new->peer) == BGP_PEER_IBGP
&& peer_sort(exist->peer) == BGP_PEER_IBGP
&& (mpath_cfg == NULL
|| CHECK_FLAG(
mpath_cfg->ibgp_flags,
BGP_FLAG_IBGP_MULTIPATH_SAME_CLUSTERLEN))) {
newm = BGP_CLUSTER_LIST_LENGTH(new->attr);
existm = BGP_CLUSTER_LIST_LENGTH(exist->attr);
if (newm < existm) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to CLUSTER_LIST length %d < %d",
pfx_buf, new_buf, exist_buf,
newm, existm);
ret = 1;
}
if (newm > existm) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to CLUSTER_LIST length %d > %d",
pfx_buf, new_buf, exist_buf,
newm, existm);
ret = 0;
}
}
}
/* 10. confed-external vs. confed-internal */
if (CHECK_FLAG(bgp->config, BGP_CONFIG_CONFEDERATION)) {
if (new_sort == BGP_PEER_CONFED
&& exist_sort == BGP_PEER_IBGP) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to confed-external peer > confed-internal peer",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (exist_sort == BGP_PEER_CONFED
&& new_sort == BGP_PEER_IBGP) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to confed-internal peer < confed-external peer",
pfx_buf, new_buf, exist_buf);
return 0;
}
}
/* 11. Maximum path check. */
if (newm == existm) {
/* If one path has a label but the other does not, do not treat
* them as equals for multipath
*/
if ((new->extra &&bgp_is_valid_label(&new->extra->label[0]))
!= (exist->extra
&& bgp_is_valid_label(&exist->extra->label[0]))) {
if (debug)
zlog_debug(
"%s: %s and %s cannot be multipath, one has a label while the other does not",
pfx_buf, new_buf, exist_buf);
} else if (bgp_flag_check(bgp,
BGP_FLAG_ASPATH_MULTIPATH_RELAX)) {
/*
* For the two paths, all comparison steps till IGP
* metric
* have succeeded - including AS_PATH hop count. Since
* 'bgp
* bestpath as-path multipath-relax' knob is on, we
* don't need
* an exact match of AS_PATH. Thus, mark the paths are
* equal.
* That will trigger both these paths to get into the
* multipath
* array.
*/
*paths_eq = 1;
if (debug)
zlog_debug(
"%s: %s and %s are equal via multipath-relax",
pfx_buf, new_buf, exist_buf);
} else if (new->peer->sort == BGP_PEER_IBGP) {
if (aspath_cmp(new->attr->aspath,
exist->attr->aspath)) {
*paths_eq = 1;
if (debug)
zlog_debug(
"%s: %s and %s are equal via matching aspaths",
pfx_buf, new_buf, exist_buf);
}
} else if (new->peer->as == exist->peer->as) {
*paths_eq = 1;
if (debug)
zlog_debug(
"%s: %s and %s are equal via same remote-as",
pfx_buf, new_buf, exist_buf);
}
} else {
/*
* TODO: If unequal cost ibgp multipath is enabled we can
* mark the paths as equal here instead of returning
*/
if (debug) {
if (ret == 1)
zlog_debug(
"%s: %s wins over %s after IGP metric comparison",
pfx_buf, new_buf, exist_buf);
else
zlog_debug(
"%s: %s loses to %s after IGP metric comparison",
pfx_buf, new_buf, exist_buf);
}
return ret;
}
/* 12. If both paths are external, prefer the path that was received
first (the oldest one). This step minimizes route-flap, since a
newer path won't displace an older one, even if it was the
preferred route based on the additional decision criteria below. */
if (!bgp_flag_check(bgp, BGP_FLAG_COMPARE_ROUTER_ID)
&& new_sort == BGP_PEER_EBGP && exist_sort == BGP_PEER_EBGP) {
if (CHECK_FLAG(new->flags, BGP_INFO_SELECTED)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to oldest external",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (CHECK_FLAG(exist->flags, BGP_INFO_SELECTED)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to oldest external",
pfx_buf, new_buf, exist_buf);
return 0;
}
}
/* 13. Router-ID comparision. */
/* If one of the paths is "stale", the corresponding peer router-id will
* be 0 and would always win over the other path. If originator id is
* used for the comparision, it will decide which path is better.
*/
if (newattr->flag & ATTR_FLAG_BIT(BGP_ATTR_ORIGINATOR_ID))
new_id.s_addr = newattr->originator_id.s_addr;
else
new_id.s_addr = new->peer->remote_id.s_addr;
if (existattr->flag & ATTR_FLAG_BIT(BGP_ATTR_ORIGINATOR_ID))
exist_id.s_addr = existattr->originator_id.s_addr;
else
exist_id.s_addr = exist->peer->remote_id.s_addr;
if (ntohl(new_id.s_addr) < ntohl(exist_id.s_addr)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to Router-ID comparison",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (ntohl(new_id.s_addr) > ntohl(exist_id.s_addr)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to Router-ID comparison",
pfx_buf, new_buf, exist_buf);
return 0;
}
/* 14. Cluster length comparision. */
new_cluster = BGP_CLUSTER_LIST_LENGTH(new->attr);
exist_cluster = BGP_CLUSTER_LIST_LENGTH(exist->attr);
if (new_cluster < exist_cluster) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to CLUSTER_LIST length %d < %d",
pfx_buf, new_buf, exist_buf, new_cluster,
exist_cluster);
return 1;
}
if (new_cluster > exist_cluster) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to CLUSTER_LIST length %d > %d",
pfx_buf, new_buf, exist_buf, new_cluster,
exist_cluster);
return 0;
}
/* 15. Neighbor address comparision. */
/* Do this only if neither path is "stale" as stale paths do not have
* valid peer information (as the connection may or may not be up).
*/
if (CHECK_FLAG(exist->flags, BGP_INFO_STALE)) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to latter path being STALE",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (CHECK_FLAG(new->flags, BGP_INFO_STALE)) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to former path being STALE",
pfx_buf, new_buf, exist_buf);
return 0;
}
/* locally configured routes to advertise do not have su_remote */
if (new->peer->su_remote == NULL)
return 0;
if (exist->peer->su_remote == NULL)
return 1;
ret = sockunion_cmp(new->peer->su_remote, exist->peer->su_remote);
if (ret == 1) {
if (debug)
zlog_debug(
"%s: %s loses to %s due to Neighor IP comparison",
pfx_buf, new_buf, exist_buf);
return 0;
}
if (ret == -1) {
if (debug)
zlog_debug(
"%s: %s wins over %s due to Neighor IP comparison",
pfx_buf, new_buf, exist_buf);
return 1;
}
if (debug)
zlog_debug("%s: %s wins over %s due to nothing left to compare",
pfx_buf, new_buf, exist_buf);
return 1;
}
/* Compare two bgp route entity. Return -1 if new is preferred, 1 if exist
* is preferred, or 0 if they are the same (usually will only occur if
* multipath is enabled
* This version is compatible with */
int bgp_info_cmp_compatible(struct bgp *bgp, struct bgp_info *new,
struct bgp_info *exist, char *pfx_buf, afi_t afi,
safi_t safi)
{
int paths_eq;