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bgp_fsm.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/* BGP-4 Finite State Machine
* From RFC1771 [A Border Gateway Protocol 4 (BGP-4)]
* Copyright (C) 1996, 97, 98 Kunihiro Ishiguro
*/
#include <zebra.h>
#include "linklist.h"
#include "prefix.h"
#include "sockunion.h"
#include "frrevent.h"
#include "log.h"
#include "stream.h"
#include "ringbuf.h"
#include "memory.h"
#include "plist.h"
#include "workqueue.h"
#include "queue.h"
#include "filter.h"
#include "command.h"
#include "lib_errors.h"
#include "zclient.h"
#include "lib/json.h"
#include "bgpd/bgpd.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_errors.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_packet.h"
#include "bgpd/bgp_network.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_dump.h"
#include "bgpd/bgp_open.h"
#include "bgpd/bgp_advertise.h"
#include "bgpd/bgp_community.h"
#include "bgpd/bgp_updgrp.h"
#include "bgpd/bgp_nht.h"
#include "bgpd/bgp_bfd.h"
#include "bgpd/bgp_memory.h"
#include "bgpd/bgp_keepalives.h"
#include "bgpd/bgp_io.h"
#include "bgpd/bgp_zebra.h"
#include "bgpd/bgp_vty.h"
DEFINE_HOOK(peer_backward_transition, (struct peer * peer), (peer));
DEFINE_HOOK(peer_status_changed, (struct peer * peer), (peer));
/* Definition of display strings corresponding to FSM events. This should be
* kept consistent with the events defined in bgpd.h
*/
static const char *const bgp_event_str[] = {
NULL,
"BGP_Start",
"BGP_Stop",
"TCP_connection_open",
"TCP_connection_open_w_delay",
"TCP_connection_closed",
"TCP_connection_open_failed",
"TCP_fatal_error",
"ConnectRetry_timer_expired",
"Hold_Timer_expired",
"KeepAlive_timer_expired",
"DelayOpen_timer_expired",
"Receive_OPEN_message",
"Receive_KEEPALIVE_message",
"Receive_UPDATE_message",
"Receive_NOTIFICATION_message",
"Clearing_Completed",
};
/* BGP FSM (finite state machine) has three types of functions. Type
one is thread functions. Type two is event functions. Type three
is FSM functions. Timer functions are set by bgp_timer_set
function. */
/* BGP event function. */
void bgp_event(struct event *event);
/* BGP thread functions. */
static void bgp_start_timer(struct event *event);
static void bgp_connect_timer(struct event *event);
static void bgp_holdtime_timer(struct event *event);
static void bgp_delayopen_timer(struct event *event);
/* Register peer with NHT */
int bgp_peer_reg_with_nht(struct peer *peer)
{
int connected = 0;
if (peer->sort == BGP_PEER_EBGP && peer->ttl == BGP_DEFAULT_TTL
&& !CHECK_FLAG(peer->flags, PEER_FLAG_DISABLE_CONNECTED_CHECK)
&& !CHECK_FLAG(peer->bgp->flags, BGP_FLAG_DISABLE_NH_CONNECTED_CHK))
connected = 1;
return bgp_find_or_add_nexthop(peer->bgp, peer->bgp,
family2afi(
peer->connection->su.sa.sa_family),
SAFI_UNICAST, NULL, peer, connected,
NULL);
}
static void peer_xfer_stats(struct peer *peer_dst, struct peer *peer_src)
{
/* Copy stats over. These are only the pre-established state stats */
peer_dst->open_in += peer_src->open_in;
peer_dst->open_out += peer_src->open_out;
peer_dst->keepalive_in += peer_src->keepalive_in;
peer_dst->keepalive_out += peer_src->keepalive_out;
peer_dst->notify_in += peer_src->notify_in;
peer_dst->notify_out += peer_src->notify_out;
peer_dst->dynamic_cap_in += peer_src->dynamic_cap_in;
peer_dst->dynamic_cap_out += peer_src->dynamic_cap_out;
}
static struct peer *peer_xfer_conn(struct peer *from_peer)
{
struct peer *peer;
afi_t afi;
safi_t safi;
enum bgp_fsm_events last_evt, last_maj_evt;
struct peer_connection *keeper, *going_away;
assert(from_peer != NULL);
/*
* Keeper is the connection that is staying around
*/
keeper = from_peer->connection;
peer = from_peer->doppelganger;
if (!peer || !CHECK_FLAG(peer->flags, PEER_FLAG_CONFIG_NODE))
return from_peer;
/*
* from_peer is pointing at the non config node and
* at this point peer is pointing at the CONFIG node
* peer ( non incoming connection ). The going_away pointer
* is the connection that is being placed on to
* the non Config node for deletion.
*/
going_away = peer->connection;
/*
* Let's check that we are not going to loose known configuration
* state based upon doppelganger rules.
*/
FOREACH_AFI_SAFI (afi, safi) {
if (from_peer->afc[afi][safi] != peer->afc[afi][safi]) {
flog_err(
EC_BGP_DOPPELGANGER_CONFIG,
"from_peer->afc[%d][%d] is not the same as what we are overwriting",
afi, safi);
return NULL;
}
}
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s: peer transfer %p fd %d -> %p fd %d)",
from_peer->host, from_peer, from_peer->connection->fd,
peer, peer->connection->fd);
bgp_writes_off(going_away);
bgp_reads_off(going_away);
bgp_writes_off(keeper);
bgp_reads_off(keeper);
/*
* Before exchanging FD remove doppelganger from
* keepalive peer hash. It could be possible conf peer
* fd is set to -1. If blocked on lock then keepalive
* thread can access peer pointer with fd -1.
*/
bgp_keepalives_off(keeper);
EVENT_OFF(going_away->t_routeadv);
EVENT_OFF(going_away->t_connect);
EVENT_OFF(going_away->t_delayopen);
EVENT_OFF(going_away->t_connect_check_r);
EVENT_OFF(going_away->t_connect_check_w);
EVENT_OFF(keeper->t_routeadv);
EVENT_OFF(keeper->t_connect);
EVENT_OFF(keeper->t_delayopen);
EVENT_OFF(keeper->t_connect_check_r);
EVENT_OFF(keeper->t_connect_check_w);
EVENT_OFF(keeper->t_process_packet);
/*
* At this point in time, it is possible that there are packets pending
* on various buffers. Those need to be transferred or dropped,
* otherwise we'll get spurious failures during session establishment.
*/
peer->connection = keeper;
keeper->peer = peer;
from_peer->connection = going_away;
going_away->peer = from_peer;
peer->as = from_peer->as;
peer->v_holdtime = from_peer->v_holdtime;
peer->v_keepalive = from_peer->v_keepalive;
peer->v_routeadv = from_peer->v_routeadv;
peer->v_delayopen = from_peer->v_delayopen;
peer->v_gr_restart = from_peer->v_gr_restart;
peer->cap = from_peer->cap;
peer->remote_role = from_peer->remote_role;
last_evt = peer->last_event;
last_maj_evt = peer->last_major_event;
peer->last_event = from_peer->last_event;
peer->last_major_event = from_peer->last_major_event;
from_peer->last_event = last_evt;
from_peer->last_major_event = last_maj_evt;
peer->remote_id = from_peer->remote_id;
peer->last_reset = from_peer->last_reset;
peer->max_packet_size = from_peer->max_packet_size;
BGP_GR_ROUTER_DETECT_AND_SEND_CAPABILITY_TO_ZEBRA(peer->bgp,
peer->bgp->peer);
if (bgp_peer_gr_mode_get(peer) == PEER_DISABLE) {
UNSET_FLAG(peer->sflags, PEER_STATUS_NSF_MODE);
if (CHECK_FLAG(peer->sflags, PEER_STATUS_NSF_WAIT)) {
peer_nsf_stop(peer);
}
}
if (peer->hostname) {
XFREE(MTYPE_BGP_PEER_HOST, peer->hostname);
peer->hostname = NULL;
}
if (from_peer->hostname != NULL) {
peer->hostname = from_peer->hostname;
from_peer->hostname = NULL;
}
if (peer->domainname) {
XFREE(MTYPE_BGP_PEER_HOST, peer->domainname);
peer->domainname = NULL;
}
if (from_peer->domainname != NULL) {
peer->domainname = from_peer->domainname;
from_peer->domainname = NULL;
}
if (peer->soft_version) {
XFREE(MTYPE_BGP_SOFT_VERSION, peer->soft_version);
peer->soft_version = NULL;
}
if (from_peer->soft_version) {
peer->soft_version = from_peer->soft_version;
from_peer->soft_version = NULL;
}
FOREACH_AFI_SAFI (afi, safi) {
peer->af_sflags[afi][safi] = from_peer->af_sflags[afi][safi];
peer->af_cap[afi][safi] = from_peer->af_cap[afi][safi];
peer->afc_nego[afi][safi] = from_peer->afc_nego[afi][safi];
peer->afc_adv[afi][safi] = from_peer->afc_adv[afi][safi];
peer->afc_recv[afi][safi] = from_peer->afc_recv[afi][safi];
peer->orf_plist[afi][safi] = from_peer->orf_plist[afi][safi];
peer->llgr[afi][safi] = from_peer->llgr[afi][safi];
}
if (bgp_getsockname(peer) < 0) {
flog_err(EC_LIB_SOCKET,
"%%bgp_getsockname() failed for %s peer %s fd %d (from_peer fd %d)",
(CHECK_FLAG(peer->sflags, PEER_STATUS_ACCEPT_PEER)
? "accept"
: ""),
peer->host, going_away->fd, keeper->fd);
BGP_EVENT_ADD(going_away, BGP_Stop);
BGP_EVENT_ADD(keeper, BGP_Stop);
return NULL;
}
if (going_away->status > Active) {
if (bgp_getsockname(from_peer) < 0) {
flog_err(EC_LIB_SOCKET,
"%%bgp_getsockname() failed for %s from_peer %s fd %d (peer fd %d)",
(CHECK_FLAG(from_peer->sflags,
PEER_STATUS_ACCEPT_PEER)
? "accept"
: ""),
from_peer->host, going_away->fd, keeper->fd);
bgp_stop(going_away);
from_peer = NULL;
}
}
// Note: peer_xfer_stats() must be called with I/O turned OFF
if (from_peer)
peer_xfer_stats(peer, from_peer);
/* Register peer for NHT. This is to allow RAs to be enabled when
* needed, even on a passive connection.
*/
bgp_peer_reg_with_nht(peer);
if (from_peer)
bgp_replace_nexthop_by_peer(from_peer, peer);
bgp_reads_on(keeper);
bgp_writes_on(keeper);
event_add_event(bm->master, bgp_process_packet, keeper, 0,
&keeper->t_process_packet);
return (peer);
}
/* Hook function called after bgp event is occered. And vty's
neighbor command invoke this function after making neighbor
structure. */
void bgp_timer_set(struct peer_connection *connection)
{
afi_t afi;
safi_t safi;
struct peer *peer = connection->peer;
switch (connection->status) {
case Idle:
/* First entry point of peer's finite state machine. In Idle
status start timer is on unless peer is shutdown or peer is
inactive. All other timer must be turned off */
if (BGP_PEER_START_SUPPRESSED(peer) || !peer_active(peer)
|| peer->bgp->vrf_id == VRF_UNKNOWN) {
EVENT_OFF(connection->t_start);
} else {
BGP_TIMER_ON(connection->t_start, bgp_start_timer,
peer->v_start);
}
EVENT_OFF(connection->t_connect);
EVENT_OFF(connection->t_holdtime);
bgp_keepalives_off(connection);
EVENT_OFF(connection->t_routeadv);
EVENT_OFF(connection->t_delayopen);
break;
case Connect:
/* After start timer is expired, the peer moves to Connect
status. Make sure start timer is off and connect timer is
on. */
EVENT_OFF(connection->t_start);
if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
BGP_TIMER_ON(connection->t_connect, bgp_connect_timer,
(peer->v_delayopen + peer->v_connect));
else
BGP_TIMER_ON(connection->t_connect, bgp_connect_timer,
peer->v_connect);
EVENT_OFF(connection->t_holdtime);
bgp_keepalives_off(connection);
EVENT_OFF(connection->t_routeadv);
break;
case Active:
/* Active is waiting connection from remote peer. And if
connect timer is expired, change status to Connect. */
EVENT_OFF(connection->t_start);
/* If peer is passive mode, do not set connect timer. */
if (CHECK_FLAG(peer->flags, PEER_FLAG_PASSIVE)
|| CHECK_FLAG(peer->sflags, PEER_STATUS_NSF_WAIT)) {
EVENT_OFF(connection->t_connect);
} else {
if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER_DELAYOPEN))
BGP_TIMER_ON(connection->t_connect,
bgp_connect_timer,
(peer->v_delayopen +
peer->v_connect));
else
BGP_TIMER_ON(connection->t_connect,
bgp_connect_timer, peer->v_connect);
}
EVENT_OFF(connection->t_holdtime);
bgp_keepalives_off(connection);
EVENT_OFF(connection->t_routeadv);
break;
case OpenSent:
/* OpenSent status. */
EVENT_OFF(connection->t_start);
EVENT_OFF(connection->t_connect);
if (peer->v_holdtime != 0) {
BGP_TIMER_ON(connection->t_holdtime, bgp_holdtime_timer,
peer->v_holdtime);
} else {
EVENT_OFF(connection->t_holdtime);
}
bgp_keepalives_off(connection);
EVENT_OFF(connection->t_routeadv);
EVENT_OFF(connection->t_delayopen);
break;
case OpenConfirm:
/* OpenConfirm status. */
EVENT_OFF(connection->t_start);
EVENT_OFF(connection->t_connect);
/*
* If the negotiated Hold Time value is zero, then the Hold Time
* timer and KeepAlive timers are not started.
* Additionally if a different hold timer has been negotiated
* than we must stop then start the timer again
*/
EVENT_OFF(connection->t_holdtime);
if (peer->v_holdtime == 0)
bgp_keepalives_off(connection);
else {
BGP_TIMER_ON(connection->t_holdtime, bgp_holdtime_timer,
peer->v_holdtime);
bgp_keepalives_on(connection);
}
EVENT_OFF(connection->t_routeadv);
EVENT_OFF(connection->t_delayopen);
break;
case Established:
/* In Established status start and connect timer is turned
off. */
EVENT_OFF(connection->t_start);
EVENT_OFF(connection->t_connect);
EVENT_OFF(connection->t_delayopen);
/*
* Same as OpenConfirm, if holdtime is zero then both holdtime
* and keepalive must be turned off.
* Additionally if a different hold timer has been negotiated
* then we must stop then start the timer again
*/
EVENT_OFF(connection->t_holdtime);
if (peer->v_holdtime == 0)
bgp_keepalives_off(connection);
else {
BGP_TIMER_ON(connection->t_holdtime, bgp_holdtime_timer,
peer->v_holdtime);
bgp_keepalives_on(connection);
}
break;
case Deleted:
EVENT_OFF(peer->connection->t_gr_restart);
EVENT_OFF(peer->connection->t_gr_stale);
FOREACH_AFI_SAFI (afi, safi)
EVENT_OFF(peer->t_llgr_stale[afi][safi]);
EVENT_OFF(peer->connection->t_pmax_restart);
EVENT_OFF(peer->t_refresh_stalepath);
/* fallthru */
case Clearing:
EVENT_OFF(connection->t_start);
EVENT_OFF(connection->t_connect);
EVENT_OFF(connection->t_holdtime);
bgp_keepalives_off(connection);
EVENT_OFF(connection->t_routeadv);
EVENT_OFF(connection->t_delayopen);
break;
case BGP_STATUS_MAX:
flog_err(EC_LIB_DEVELOPMENT,
"BGP_STATUS_MAX while a legal state is not valid state for the FSM");
break;
}
}
/* BGP start timer. This function set BGP_Start event to thread value
and process event. */
static void bgp_start_timer(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [FSM] Timer (start timer expire).", peer->host);
EVENT_VAL(thread) = BGP_Start;
bgp_event(thread); /* bgp_event unlocks peer */
}
/* BGP connect retry timer. */
static void bgp_connect_timer(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
/* stop the DelayOpenTimer if it is running */
EVENT_OFF(connection->t_delayopen);
assert(!connection->t_write);
assert(!connection->t_read);
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [FSM] Timer (connect timer expire)", peer->host);
if (CHECK_FLAG(peer->sflags, PEER_STATUS_ACCEPT_PEER))
bgp_stop(connection);
else {
EVENT_VAL(thread) = ConnectRetry_timer_expired;
bgp_event(thread); /* bgp_event unlocks peer */
}
}
/* BGP holdtime timer. */
static void bgp_holdtime_timer(struct event *thread)
{
atomic_size_t inq_count;
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [FSM] Timer (holdtime timer expire)",
peer->host);
/*
* Given that we do not have any expectation of ordering
* for handling packets from a peer -vs- handling
* the hold timer for a peer as that they are both
* events on the peer. If we have incoming
* data on the peers inq, let's give the system a chance
* to handle that data. This can be especially true
* for systems where we are heavily loaded for one
* reason or another.
*/
inq_count = atomic_load_explicit(&connection->ibuf->count,
memory_order_relaxed);
if (inq_count)
BGP_TIMER_ON(connection->t_holdtime, bgp_holdtime_timer,
peer->v_holdtime);
EVENT_VAL(thread) = Hold_Timer_expired;
bgp_event(thread); /* bgp_event unlocks peer */
}
void bgp_routeadv_timer(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [FSM] Timer (routeadv timer expire)", peer->host);
peer->synctime = monotime(NULL);
event_add_timer_msec(bm->master, bgp_generate_updgrp_packets, connection,
0, &connection->t_generate_updgrp_packets);
/* MRAI timer will be started again when FIFO is built, no need to
* do it here.
*/
}
/* RFC 4271 DelayOpenTimer */
void bgp_delayopen_timer(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [FSM] Timer (DelayOpentimer expire)",
peer->host);
EVENT_VAL(thread) = DelayOpen_timer_expired;
bgp_event(thread); /* bgp_event unlocks peer */
}
/* BGP Peer Down Cause */
const char *const peer_down_str[] = {"",
"Router ID changed",
"Remote AS changed",
"Local AS change",
"Cluster ID changed",
"Confederation identifier changed",
"Confederation peer changed",
"RR client config change",
"RS client config change",
"Update source change",
"Address family activated",
"Admin. shutdown",
"User reset",
"BGP Notification received",
"BGP Notification send",
"Peer closed the session",
"Neighbor deleted",
"Peer-group add member",
"Peer-group delete member",
"Capability changed",
"Passive config change",
"Multihop config change",
"NSF peer closed the session",
"Intf peering v6only config change",
"BFD down received",
"Interface down",
"Neighbor address lost",
"No path to specified Neighbor",
"Waiting for Peer IPv6 LLA",
"Waiting for VRF to be initialized",
"No AFI/SAFI activated for peer",
"AS Set config change",
"Waiting for peer OPEN",
"Reached received prefix count",
"Socket Error",
"Admin. shutdown (RTT)"};
static void bgp_graceful_restart_timer_off(struct peer_connection *connection,
struct peer *peer)
{
afi_t afi;
safi_t safi;
FOREACH_AFI_SAFI (afi, safi)
if (CHECK_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_LLGR_WAIT))
return;
UNSET_FLAG(peer->sflags, PEER_STATUS_NSF_WAIT);
EVENT_OFF(connection->t_gr_stale);
if (peer_dynamic_neighbor(peer) &&
!(CHECK_FLAG(peer->flags, PEER_FLAG_DELETE))) {
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s (dynamic neighbor) deleted (%s)",
peer->host, __func__);
peer_delete(peer);
}
bgp_timer_set(connection);
}
static void bgp_llgr_stale_timer_expire(struct event *thread)
{
struct peer_af *paf;
struct peer *peer;
afi_t afi;
safi_t safi;
paf = EVENT_ARG(thread);
peer = paf->peer;
afi = paf->afi;
safi = paf->safi;
/* If the timer for the "Long-lived Stale Time" expires before the
* session is re-established, the helper MUST delete all the
* stale routes from the neighbor that it is retaining.
*/
if (bgp_debug_neighbor_events(peer))
zlog_debug("%pBP Long-lived stale timer (%s) expired", peer,
get_afi_safi_str(afi, safi, false));
UNSET_FLAG(peer->af_sflags[afi][safi], PEER_STATUS_LLGR_WAIT);
bgp_clear_stale_route(peer, afi, safi);
bgp_graceful_restart_timer_off(peer->connection, peer);
}
static void bgp_set_llgr_stale(struct peer *peer, afi_t afi, safi_t safi)
{
struct bgp_dest *dest;
struct bgp_path_info *pi;
struct bgp_table *table;
struct attr attr;
if (safi == SAFI_MPLS_VPN || safi == SAFI_ENCAP || safi == SAFI_EVPN) {
for (dest = bgp_table_top(peer->bgp->rib[afi][safi]); dest;
dest = bgp_route_next(dest)) {
struct bgp_dest *rm;
table = bgp_dest_get_bgp_table_info(dest);
if (!table)
continue;
for (rm = bgp_table_top(table); rm;
rm = bgp_route_next(rm))
for (pi = bgp_dest_get_bgp_path_info(rm); pi;
pi = pi->next) {
if (pi->peer != peer)
continue;
if (bgp_attr_get_community(pi->attr) &&
community_include(
bgp_attr_get_community(
pi->attr),
COMMUNITY_NO_LLGR))
continue;
if (bgp_debug_neighbor_events(peer))
zlog_debug(
"%pBP Long-lived set stale community (LLGR_STALE) for: %pFX",
peer, &dest->rn->p);
attr = *pi->attr;
bgp_attr_add_llgr_community(&attr);
pi->attr = bgp_attr_intern(&attr);
bgp_recalculate_afi_safi_bestpaths(
peer->bgp, afi, safi);
break;
}
}
} else {
for (dest = bgp_table_top(peer->bgp->rib[afi][safi]); dest;
dest = bgp_route_next(dest))
for (pi = bgp_dest_get_bgp_path_info(dest); pi;
pi = pi->next) {
if (pi->peer != peer)
continue;
if (bgp_attr_get_community(pi->attr) &&
community_include(
bgp_attr_get_community(pi->attr),
COMMUNITY_NO_LLGR))
continue;
if (bgp_debug_neighbor_events(peer))
zlog_debug(
"%pBP Long-lived set stale community (LLGR_STALE) for: %pFX",
peer, &dest->rn->p);
attr = *pi->attr;
bgp_attr_add_llgr_community(&attr);
pi->attr = bgp_attr_intern(&attr);
bgp_recalculate_afi_safi_bestpaths(peer->bgp,
afi, safi);
break;
}
}
}
static void bgp_graceful_restart_timer_expire(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
struct peer *tmp_peer;
struct listnode *node, *nnode;
struct peer_af *paf;
afi_t afi;
safi_t safi;
if (bgp_debug_neighbor_events(peer)) {
zlog_debug("%pBP graceful restart timer expired", peer);
zlog_debug("%pBP graceful restart stalepath timer stopped",
peer);
}
FOREACH_AFI_SAFI (afi, safi) {
if (!peer->nsf[afi][safi])
continue;
/* Once the "Restart Time" period ends, the LLGR period is
* said to have begun and the following procedures MUST be
* performed:
*
* The helper router MUST start a timer for the
* "Long-lived Stale Time".
*
* The helper router MUST attach the LLGR_STALE community
* for the stale routes being retained. Note that this
* requirement implies that the routes would need to be
* readvertised, to disseminate the modified community.
*/
if (peer->llgr[afi][safi].stale_time) {
paf = peer_af_find(peer, afi, safi);
if (!paf)
continue;
if (bgp_debug_neighbor_events(peer))
zlog_debug(
"%pBP Long-lived stale timer (%s) started for %d sec",
peer,
get_afi_safi_str(afi, safi, false),
peer->llgr[afi][safi].stale_time);
SET_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_LLGR_WAIT);
bgp_set_llgr_stale(peer, afi, safi);
bgp_clear_stale_route(peer, afi, safi);
event_add_timer(bm->master, bgp_llgr_stale_timer_expire,
paf, peer->llgr[afi][safi].stale_time,
&peer->t_llgr_stale[afi][safi]);
for (ALL_LIST_ELEMENTS(peer->bgp->peer, node, nnode,
tmp_peer))
bgp_announce_route(tmp_peer, afi, safi, false);
} else {
bgp_clear_stale_route(peer, afi, safi);
}
}
bgp_graceful_restart_timer_off(connection, peer);
}
static void bgp_graceful_stale_timer_expire(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
afi_t afi;
safi_t safi;
if (bgp_debug_neighbor_events(peer))
zlog_debug("%pBP graceful restart stalepath timer expired",
peer);
/* NSF delete stale route */
FOREACH_AFI_SAFI_NSF (afi, safi)
if (peer->nsf[afi][safi])
bgp_clear_stale_route(peer, afi, safi);
}
/* Selection deferral timer processing function */
static void bgp_graceful_deferral_timer_expire(struct event *thread)
{
struct afi_safi_info *info;
afi_t afi;
safi_t safi;
struct bgp *bgp;
info = EVENT_ARG(thread);
afi = info->afi;
safi = info->safi;
bgp = info->bgp;
if (BGP_DEBUG(update, UPDATE_OUT))
zlog_debug(
"afi %d, safi %d : graceful restart deferral timer expired",
afi, safi);
bgp->gr_info[afi][safi].eor_required = 0;
bgp->gr_info[afi][safi].eor_received = 0;
XFREE(MTYPE_TMP, info);
/* Best path selection */
bgp_best_path_select_defer(bgp, afi, safi);
}
static bool bgp_update_delay_applicable(struct bgp *bgp)
{
/* update_delay_over flag should be reset (set to 0) for any new
applicability of the update-delay during BGP process lifetime.
And it should be set after an occurence of the update-delay is
over)*/
if (!bgp->update_delay_over)
return true;
return false;
}
bool bgp_update_delay_active(struct bgp *bgp)
{
if (bgp->t_update_delay)
return true;
return false;
}
bool bgp_update_delay_configured(struct bgp *bgp)
{
if (bgp->v_update_delay)
return true;
return false;
}
/* Do the post-processing needed when bgp comes out of the read-only mode
on ending the update delay. */
void bgp_update_delay_end(struct bgp *bgp)
{
EVENT_OFF(bgp->t_update_delay);
EVENT_OFF(bgp->t_establish_wait);
/* Reset update-delay related state */
bgp->update_delay_over = 1;
bgp->established = 0;
bgp->restarted_peers = 0;
bgp->implicit_eors = 0;
bgp->explicit_eors = 0;
frr_timestamp(3, bgp->update_delay_end_time,
sizeof(bgp->update_delay_end_time));
/*
* Add an end-of-initial-update marker to the main process queues so
* that
* the route advertisement timer for the peers can be started. Also set
* the zebra and peer update hold flags. These flags are used to achieve
* three stages in the update-delay post processing:
* 1. Finish best-path selection for all the prefixes held on the
* queues.
* (routes in BGP are updated, and peers sync queues are populated
* too)
* 2. As the eoiu mark is reached in the bgp process routine, ship all
* the
* routes to zebra. With that zebra should see updates from BGP
* close
* to each other.
* 3. Unblock the peer update writes. With that peer update packing
* with
* the prefixes should be at its maximum.
*/
bgp_add_eoiu_mark(bgp);
bgp->main_zebra_update_hold = 1;
bgp->main_peers_update_hold = 1;
/*
* Resume the queue processing. This should trigger the event that would
* take care of processing any work that was queued during the read-only
* mode.
*/
work_queue_unplug(bgp->process_queue);
}
/**
* see bgp_fsm.h
*/
void bgp_start_routeadv(struct bgp *bgp)
{
struct listnode *node, *nnode;
struct peer *peer;
zlog_info("%s, update hold status %d", __func__,
bgp->main_peers_update_hold);
if (bgp->main_peers_update_hold)
return;
frr_timestamp(3, bgp->update_delay_peers_resume_time,
sizeof(bgp->update_delay_peers_resume_time));
for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
struct peer_connection *connection = peer->connection;
if (!peer_established(connection))
continue;
EVENT_OFF(connection->t_routeadv);
BGP_TIMER_ON(connection->t_routeadv, bgp_routeadv_timer, 0);
}
}
/**
* see bgp_fsm.h
*/
void bgp_adjust_routeadv(struct peer *peer)
{
time_t nowtime = monotime(NULL);
double diff;
unsigned long remain;
struct peer_connection *connection = peer->connection;
/* Bypass checks for special case of MRAI being 0 */
if (peer->v_routeadv == 0) {
/* Stop existing timer, just in case it is running for a
* different
* duration and schedule write thread immediately.
*/
EVENT_OFF(connection->t_routeadv);
peer->synctime = monotime(NULL);
/* If suppress fib pending is enabled, route is advertised to
* peers when the status is received from the FIB. The delay
* is added to update group packet generate which will allow
* more routes to be sent in the update message
*/
BGP_UPDATE_GROUP_TIMER_ON(&connection->t_generate_updgrp_packets,
bgp_generate_updgrp_packets);
return;
}
/*
* CASE I:
* If the last update was written more than MRAI back, expire the timer
* instantly so that we can send the update out sooner.
*
* <------- MRAI --------->
* |-----------------|-----------------------|
* <------------- m ------------>
* ^ ^ ^
* | | |
* | | current time
* | timer start
* last write
*
* m > MRAI
*/
diff = difftime(nowtime, peer->last_update);
if (diff > (double)peer->v_routeadv) {
EVENT_OFF(connection->t_routeadv);
BGP_TIMER_ON(connection->t_routeadv, bgp_routeadv_timer, 0);
return;
}
/*
* CASE II:
* - Find when to expire the MRAI timer.
* If MRAI timer is not active, assume we can start it now.
*
* <------- MRAI --------->
* |------------|-----------------------|
* <-------- m ----------><----- r ----->
* ^ ^ ^
* | | |