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bgp_packet.c
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bgp_packet.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/* BGP packet management routine.
* Contains utility functions for constructing and consuming BGP messages.
* Copyright (C) 2017 Cumulus Networks
* Copyright (C) 1999 Kunihiro Ishiguro
*/
#include <zebra.h>
#include <sys/time.h>
#include "frrevent.h"
#include "stream.h"
#include "network.h"
#include "prefix.h"
#include "command.h"
#include "log.h"
#include "memory.h"
#include "sockunion.h" /* for inet_ntop () */
#include "sockopt.h"
#include "linklist.h"
#include "plist.h"
#include "queue.h"
#include "filter.h"
#include "lib_errors.h"
#include "bgpd/bgpd.h"
#include "bgpd/bgp_table.h"
#include "bgpd/bgp_dump.h"
#include "bgpd/bgp_bmp.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_errors.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_route.h"
#include "bgpd/bgp_packet.h"
#include "bgpd/bgp_open.h"
#include "bgpd/bgp_aspath.h"
#include "bgpd/bgp_community.h"
#include "bgpd/bgp_ecommunity.h"
#include "bgpd/bgp_lcommunity.h"
#include "bgpd/bgp_network.h"
#include "bgpd/bgp_mplsvpn.h"
#include "bgpd/bgp_evpn.h"
#include "bgpd/bgp_advertise.h"
#include "bgpd/bgp_vty.h"
#include "bgpd/bgp_updgrp.h"
#include "bgpd/bgp_label.h"
#include "bgpd/bgp_io.h"
#include "bgpd/bgp_keepalives.h"
#include "bgpd/bgp_flowspec.h"
#include "bgpd/bgp_trace.h"
DEFINE_HOOK(bgp_packet_dump,
(struct peer *peer, uint8_t type, bgp_size_t size,
struct stream *s),
(peer, type, size, s));
DEFINE_HOOK(bgp_packet_send,
(struct peer *peer, uint8_t type, bgp_size_t size,
struct stream *s),
(peer, type, size, s));
/**
* Sets marker and type fields for a BGP message.
*
* @param s the stream containing the packet
* @param type the packet type
* @return the size of the stream
*/
int bgp_packet_set_marker(struct stream *s, uint8_t type)
{
int i;
/* Fill in marker. */
for (i = 0; i < BGP_MARKER_SIZE; i++)
stream_putc(s, 0xff);
/* Dummy total length. This field is should be filled in later on. */
stream_putw(s, 0);
/* BGP packet type. */
stream_putc(s, type);
/* Return current stream size. */
return stream_get_endp(s);
}
/**
* Sets size field for a BGP message.
*
* Size field is set to the size of the stream passed.
*
* @param s the stream containing the packet
*/
void bgp_packet_set_size(struct stream *s)
{
int cp;
/* Preserve current pointer. */
cp = stream_get_endp(s);
stream_putw_at(s, BGP_MARKER_SIZE, cp);
}
/*
* Push a packet onto the beginning of the peer's output queue.
* This function acquires the peer's write mutex before proceeding.
*/
static void bgp_packet_add(struct peer_connection *connection,
struct peer *peer, struct stream *s)
{
intmax_t delta;
uint32_t holdtime;
intmax_t sendholdtime;
frr_with_mutex (&connection->io_mtx) {
/* if the queue is empty, reset the "last OK" timestamp to
* now, otherwise if we write another packet immediately
* after it'll get confused
*/
if (!stream_fifo_count_safe(connection->obuf))
peer->last_sendq_ok = monotime(NULL);
stream_fifo_push(connection->obuf, s);
delta = monotime(NULL) - peer->last_sendq_ok;
if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER))
holdtime = atomic_load_explicit(&peer->holdtime,
memory_order_relaxed);
else
holdtime = peer->bgp->default_holdtime;
sendholdtime = holdtime * 2;
/* Note that when we're here, we're adding some packet to the
* OutQ. That includes keepalives when there is nothing to
* do, so there's a guarantee we pass by here once in a while.
*
* That implies there is no need to go set up another separate
* timer that ticks down SendHoldTime, as we'll be here sooner
* or later anyway and will see the checks below failing.
*/
if (!holdtime) {
/* no holdtime, do nothing. */
} else if (delta > sendholdtime) {
flog_err(
EC_BGP_SENDQ_STUCK_PROPER,
"%pBP has not made any SendQ progress for 2 holdtimes (%jds), terminating session",
peer, sendholdtime);
BGP_EVENT_ADD(connection, TCP_fatal_error);
} else if (delta > (intmax_t)holdtime &&
monotime(NULL) - peer->last_sendq_warn > 5) {
flog_warn(
EC_BGP_SENDQ_STUCK_WARN,
"%pBP has not made any SendQ progress for 1 holdtime (%us), peer overloaded?",
peer, holdtime);
peer->last_sendq_warn = monotime(NULL);
}
}
}
static struct stream *bgp_update_packet_eor(struct peer *peer, afi_t afi,
safi_t safi)
{
struct stream *s;
iana_afi_t pkt_afi = IANA_AFI_IPV4;
iana_safi_t pkt_safi = IANA_SAFI_UNICAST;
if (DISABLE_BGP_ANNOUNCE)
return NULL;
if (bgp_debug_neighbor_events(peer))
zlog_debug("send End-of-RIB for %s to %s",
get_afi_safi_str(afi, safi, false), peer->host);
s = stream_new(peer->max_packet_size);
/* Make BGP update packet. */
bgp_packet_set_marker(s, BGP_MSG_UPDATE);
/* Unfeasible Routes Length */
stream_putw(s, 0);
if (afi == AFI_IP && safi == SAFI_UNICAST) {
/* Total Path Attribute Length */
stream_putw(s, 0);
} else {
/* Convert AFI, SAFI to values for packet. */
bgp_map_afi_safi_int2iana(afi, safi, &pkt_afi, &pkt_safi);
/* Total Path Attribute Length */
stream_putw(s, 6);
stream_putc(s, BGP_ATTR_FLAG_OPTIONAL);
stream_putc(s, BGP_ATTR_MP_UNREACH_NLRI);
stream_putc(s, 3);
stream_putw(s, pkt_afi);
stream_putc(s, pkt_safi);
}
bgp_packet_set_size(s);
return s;
}
/* Called when there is a change in the EOR(implicit or explicit) status of a
* peer. Ends the update-delay if all expected peers are done with EORs. */
void bgp_check_update_delay(struct bgp *bgp)
{
struct listnode *node, *nnode;
struct peer *peer = NULL;
if (bgp_debug_neighbor_events(peer))
zlog_debug("Checking update delay, T: %d R: %d I:%d E: %d",
bgp->established, bgp->restarted_peers,
bgp->implicit_eors, bgp->explicit_eors);
if (bgp->established
<= bgp->restarted_peers + bgp->implicit_eors + bgp->explicit_eors) {
/*
* This is an extra sanity check to make sure we wait for all
* the eligible configured peers. This check is performed if
* establish wait timer is on, or establish wait option is not
* given with the update-delay command
*/
if (bgp->t_establish_wait
|| (bgp->v_establish_wait == bgp->v_update_delay))
for (ALL_LIST_ELEMENTS(bgp->peer, node, nnode, peer)) {
if (CHECK_FLAG(peer->flags,
PEER_FLAG_CONFIG_NODE)
&& !CHECK_FLAG(peer->flags,
PEER_FLAG_SHUTDOWN)
&& !CHECK_FLAG(peer->bgp->flags,
BGP_FLAG_SHUTDOWN)
&& !peer->update_delay_over) {
if (bgp_debug_neighbor_events(peer))
zlog_debug(
" Peer %s pending, continuing read-only mode",
peer->host);
return;
}
}
zlog_info(
"Update delay ended, restarted: %d, EORs implicit: %d, explicit: %d",
bgp->restarted_peers, bgp->implicit_eors,
bgp->explicit_eors);
bgp_update_delay_end(bgp);
}
}
/*
* Called if peer is known to have restarted. The restart-state bit in
* Graceful-Restart capability is used for that
*/
void bgp_update_restarted_peers(struct peer *peer)
{
if (!bgp_update_delay_active(peer->bgp))
return; /* BGP update delay has ended */
if (peer->update_delay_over)
return; /* This peer has already been considered */
if (bgp_debug_neighbor_events(peer))
zlog_debug("Peer %s: Checking restarted", peer->host);
if (peer_established(peer->connection)) {
peer->update_delay_over = 1;
peer->bgp->restarted_peers++;
bgp_check_update_delay(peer->bgp);
}
}
/*
* Called as peer receives a keep-alive. Determines if this occurence can be
* taken as an implicit EOR for this peer.
* NOTE: The very first keep-alive after the Established state of a peer is
* considered implicit EOR for the update-delay purposes
*/
void bgp_update_implicit_eors(struct peer *peer)
{
if (!bgp_update_delay_active(peer->bgp))
return; /* BGP update delay has ended */
if (peer->update_delay_over)
return; /* This peer has already been considered */
if (bgp_debug_neighbor_events(peer))
zlog_debug("Peer %s: Checking implicit EORs", peer->host);
if (peer_established(peer->connection)) {
peer->update_delay_over = 1;
peer->bgp->implicit_eors++;
bgp_check_update_delay(peer->bgp);
}
}
/*
* Should be called only when there is a change in the EOR_RECEIVED status
* for any afi/safi on a peer.
*/
static void bgp_update_explicit_eors(struct peer *peer)
{
afi_t afi;
safi_t safi;
if (!bgp_update_delay_active(peer->bgp))
return; /* BGP update delay has ended */
if (peer->update_delay_over)
return; /* This peer has already been considered */
if (bgp_debug_neighbor_events(peer))
zlog_debug("Peer %s: Checking explicit EORs", peer->host);
FOREACH_AFI_SAFI (afi, safi) {
if (peer->afc_nego[afi][safi]
&& !CHECK_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_EOR_RECEIVED)) {
if (bgp_debug_neighbor_events(peer))
zlog_debug(
" afi %d safi %d didn't receive EOR",
afi, safi);
return;
}
}
peer->update_delay_over = 1;
peer->bgp->explicit_eors++;
bgp_check_update_delay(peer->bgp);
}
/**
* Frontend for NLRI parsing, to fan-out to AFI/SAFI specific parsers.
*
* mp_withdraw, if set, is used to nullify attr structure on most of the
* calling safi function and for evpn, passed as parameter
*/
int bgp_nlri_parse(struct peer *peer, struct attr *attr,
struct bgp_nlri *packet, bool mp_withdraw)
{
switch (packet->safi) {
case SAFI_UNICAST:
case SAFI_MULTICAST:
return bgp_nlri_parse_ip(peer, mp_withdraw ? NULL : attr,
packet);
case SAFI_LABELED_UNICAST:
return bgp_nlri_parse_label(peer, mp_withdraw ? NULL : attr,
packet);
case SAFI_MPLS_VPN:
return bgp_nlri_parse_vpn(peer, mp_withdraw ? NULL : attr,
packet);
case SAFI_EVPN:
return bgp_nlri_parse_evpn(peer, attr, packet, mp_withdraw);
case SAFI_FLOWSPEC:
return bgp_nlri_parse_flowspec(peer, attr, packet, mp_withdraw);
}
return BGP_NLRI_PARSE_ERROR;
}
/*
* Check if route-refresh request from peer is pending (received before EoR),
* and process it now.
*/
static void bgp_process_pending_refresh(struct peer *peer, afi_t afi,
safi_t safi)
{
if (CHECK_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_REFRESH_PENDING)) {
UNSET_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_REFRESH_PENDING);
bgp_route_refresh_send(peer, afi, safi, 0, 0, 0,
BGP_ROUTE_REFRESH_BORR);
if (bgp_debug_neighbor_events(peer))
zlog_debug(
"%pBP sending route-refresh (BoRR) for %s/%s (for pending REQUEST)",
peer, afi2str(afi), safi2str(safi));
SET_FLAG(peer->af_sflags[afi][safi], PEER_STATUS_BORR_SEND);
UNSET_FLAG(peer->af_sflags[afi][safi], PEER_STATUS_EORR_SEND);
bgp_announce_route(peer, afi, safi, true);
}
}
/*
* Checks a variety of conditions to determine whether the peer needs to be
* rescheduled for packet generation again, and does so if necessary.
*
* @param peer to check for rescheduling
*/
static void bgp_write_proceed_actions(struct peer *peer)
{
afi_t afi;
safi_t safi;
struct peer_af *paf;
struct bpacket *next_pkt;
struct update_subgroup *subgrp;
enum bgp_af_index index;
struct peer_connection *connection = peer->connection;
for (index = BGP_AF_START; index < BGP_AF_MAX; index++) {
paf = peer->peer_af_array[index];
if (!paf)
continue;
subgrp = paf->subgroup;
if (!subgrp)
continue;
next_pkt = paf->next_pkt_to_send;
if (next_pkt && next_pkt->buffer) {
BGP_TIMER_ON(connection->t_generate_updgrp_packets,
bgp_generate_updgrp_packets, 0);
return;
}
/* No packets readily available for AFI/SAFI, are there
* subgroup packets
* that need to be generated? */
if (bpacket_queue_is_full(SUBGRP_INST(subgrp),
SUBGRP_PKTQ(subgrp))
|| subgroup_packets_to_build(subgrp)) {
BGP_TIMER_ON(connection->t_generate_updgrp_packets,
bgp_generate_updgrp_packets, 0);
return;
}
afi = paf->afi;
safi = paf->safi;
/* No packets to send, see if EOR is pending */
if (CHECK_FLAG(peer->cap, PEER_CAP_RESTART_RCV)) {
if (!subgrp->t_coalesce && peer->afc_nego[afi][safi]
&& peer->synctime
&& !CHECK_FLAG(peer->af_sflags[afi][safi],
PEER_STATUS_EOR_SEND)
&& safi != SAFI_MPLS_VPN) {
BGP_TIMER_ON(connection->t_generate_updgrp_packets,
bgp_generate_updgrp_packets, 0);
return;
}
}
}
}
/*
* Generate advertisement information (withdraws, updates, EOR) from each
* update group a peer belongs to, encode this information into packets, and
* enqueue the packets onto the peer's output buffer.
*/
void bgp_generate_updgrp_packets(struct event *thread)
{
struct peer_connection *connection = EVENT_ARG(thread);
struct peer *peer = connection->peer;
struct stream *s;
struct peer_af *paf;
struct bpacket *next_pkt;
uint32_t wpq;
uint32_t generated = 0;
afi_t afi;
safi_t safi;
wpq = atomic_load_explicit(&peer->bgp->wpkt_quanta,
memory_order_relaxed);
/*
* The code beyond this part deals with update packets, proceed only
* if peer is Established and updates are not on hold (as part of
* update-delay processing).
*/
if (!peer_established(peer->connection))
return;
if ((peer->bgp->main_peers_update_hold)
|| bgp_update_delay_active(peer->bgp))
return;
if (peer->connection->t_routeadv)
return;
/*
* Since the following is a do while loop
* let's stop adding to the outq if we are
* already at the limit.
*/
if (connection->obuf->count >= bm->outq_limit) {
bgp_write_proceed_actions(peer);
return;
}
do {
enum bgp_af_index index;
s = NULL;
for (index = BGP_AF_START; index < BGP_AF_MAX; index++) {
paf = peer->peer_af_array[index];
if (!paf || !PAF_SUBGRP(paf))
continue;
afi = paf->afi;
safi = paf->safi;
next_pkt = paf->next_pkt_to_send;
/*
* Try to generate a packet for the peer if we are at
* the end of the list. Always try to push out
* WITHDRAWs first.
*/
if (!next_pkt || !next_pkt->buffer) {
next_pkt = subgroup_withdraw_packet(
PAF_SUBGRP(paf));
if (!next_pkt || !next_pkt->buffer)
subgroup_update_packet(PAF_SUBGRP(paf));
next_pkt = paf->next_pkt_to_send;
}
/*
* If we still don't have a packet to send to the peer,
* then try to find out out if we have to send eor or
* if not, skip to the next AFI, SAFI. Don't send the
* EOR prematurely; if the subgroup's coalesce timer is
* running, the adjacency-out structure is not created
* yet.
*/
if (!next_pkt || !next_pkt->buffer) {
if (!paf->t_announce_route) {
/* Make sure we supress BGP UPDATES
* for normal processing later again.
*/
UNSET_FLAG(paf->subgroup->sflags,
SUBGRP_STATUS_FORCE_UPDATES);
/* If route-refresh BoRR message was
* already sent and we are done with
* re-announcing tables for a decent
* afi/safi, we ready to send
* EoRR request.
*/
if (CHECK_FLAG(
peer->af_sflags[afi][safi],
PEER_STATUS_BORR_SEND)) {
bgp_route_refresh_send(
peer, afi, safi, 0, 0,
0,
BGP_ROUTE_REFRESH_EORR);
SET_FLAG(peer->af_sflags[afi]
[safi],
PEER_STATUS_EORR_SEND);
UNSET_FLAG(
peer->af_sflags[afi]
[safi],
PEER_STATUS_BORR_SEND);
if (bgp_debug_neighbor_events(
peer))
zlog_debug(
"%pBP sending route-refresh (EoRR) for %s/%s",
peer,
afi2str(afi),
safi2str(safi));
}
}
if (CHECK_FLAG(peer->cap,
PEER_CAP_RESTART_RCV)) {
if (!(PAF_SUBGRP(paf))->t_coalesce
&& peer->afc_nego[afi][safi]
&& peer->synctime
&& !CHECK_FLAG(
peer->af_sflags[afi][safi],
PEER_STATUS_EOR_SEND)) {
/* If EOR is disabled,
* the message is not sent
*/
if (BGP_SEND_EOR(peer->bgp, afi,
safi)) {
SET_FLAG(
peer->af_sflags
[afi]
[safi],
PEER_STATUS_EOR_SEND);
/* Update EOR
* send time
*/
peer->eor_stime[afi]
[safi] =
monotime(NULL);
BGP_UPDATE_EOR_PKT(
peer, afi, safi,
s);
bgp_process_pending_refresh(
peer, afi,
safi);
}
}
}
continue;
}
/* Update packet send time */
peer->pkt_stime[afi][safi] = monotime(NULL);
/* Found a packet template to send, overwrite
* packet with appropriate attributes from peer
* and advance peer */
s = bpacket_reformat_for_peer(next_pkt, paf);
bgp_packet_add(connection, peer, s);
bpacket_queue_advance_peer(paf);
}
} while (s && (++generated < wpq) &&
(connection->obuf->count <= bm->outq_limit));
if (generated)
bgp_writes_on(connection);
bgp_write_proceed_actions(peer);
}
/*
* Creates a BGP Keepalive packet and appends it to the peer's output queue.
*/
void bgp_keepalive_send(struct peer *peer)
{
struct stream *s;
s = stream_new(BGP_STANDARD_MESSAGE_MAX_PACKET_SIZE);
/* Make keepalive packet. */
bgp_packet_set_marker(s, BGP_MSG_KEEPALIVE);
/* Set packet size. */
bgp_packet_set_size(s);
/* Dump packet if debug option is set. */
/* bgp_packet_dump (s); */
if (bgp_debug_keepalive(peer))
zlog_debug("%s sending KEEPALIVE", peer->host);
/* Add packet to the peer. */
bgp_packet_add(peer->connection, peer, s);
bgp_writes_on(peer->connection);
}
/*
* Creates a BGP Open packet and appends it to the peer's output queue.
* Sets capabilities as necessary.
*/
void bgp_open_send(struct peer_connection *connection)
{
struct stream *s;
uint16_t send_holdtime;
as_t local_as;
struct peer *peer = connection->peer;
if (CHECK_FLAG(peer->flags, PEER_FLAG_TIMER))
send_holdtime = peer->holdtime;
else
send_holdtime = peer->bgp->default_holdtime;
/* local-as Change */
if (peer->change_local_as)
local_as = peer->change_local_as;
else
local_as = peer->local_as;
s = stream_new(BGP_STANDARD_MESSAGE_MAX_PACKET_SIZE);
/* Make open packet. */
bgp_packet_set_marker(s, BGP_MSG_OPEN);
/* Set open packet values. */
stream_putc(s, BGP_VERSION_4); /* BGP version */
stream_putw(s, (local_as <= BGP_AS_MAX) ? (uint16_t)local_as
: BGP_AS_TRANS);
stream_putw(s, send_holdtime); /* Hold Time */
stream_put_in_addr(s, &peer->local_id); /* BGP Identifier */
/* Set capabilities */
if (CHECK_FLAG(peer->flags, PEER_FLAG_EXTENDED_OPT_PARAMS)) {
(void)bgp_open_capability(s, peer, true);
} else {
struct stream *tmp = stream_new(STREAM_SIZE(s));
stream_copy(tmp, s);
if (bgp_open_capability(tmp, peer, false)
> BGP_OPEN_NON_EXT_OPT_LEN) {
stream_free(tmp);
(void)bgp_open_capability(s, peer, true);
} else {
stream_copy(s, tmp);
stream_free(tmp);
}
}
/* Set BGP packet length. */
bgp_packet_set_size(s);
if (bgp_debug_neighbor_events(peer))
zlog_debug(
"%s sending OPEN, version %d, my as %u, holdtime %d, id %pI4",
peer->host, BGP_VERSION_4, local_as, send_holdtime,
&peer->local_id);
/* Dump packet if debug option is set. */
/* bgp_packet_dump (s); */
hook_call(bgp_packet_send, peer, BGP_MSG_OPEN, stream_get_endp(s), s);
/* Add packet to the peer. */
bgp_packet_add(connection, peer, s);
bgp_writes_on(connection);
}
/*
* Writes NOTIFICATION message directly to a peer socket without waiting for
* the I/O thread.
*
* There must be exactly one stream on the peer->connection->obuf FIFO, and the
* data within this stream must match the format of a BGP NOTIFICATION message.
* Transmission is best-effort.
*
* @requires peer->connection->io_mtx
* @param peer
* @return 0
*/
static void bgp_write_notify(struct peer_connection *connection,
struct peer *peer)
{
int ret, val;
uint8_t type;
struct stream *s;
/* There should be at least one packet. */
s = stream_fifo_pop(connection->obuf);
if (!s)
return;
assert(stream_get_endp(s) >= BGP_HEADER_SIZE);
/*
* socket is in nonblocking mode, if we can't deliver the NOTIFY, well,
* we only care about getting a clean shutdown at this point.
*/
ret = write(connection->fd, STREAM_DATA(s), stream_get_endp(s));
/*
* only connection reset/close gets counted as TCP_fatal_error, failure
* to write the entire NOTIFY doesn't get different FSM treatment
*/
if (ret <= 0) {
stream_free(s);
BGP_EVENT_ADD(connection, TCP_fatal_error);
return;
}
/* Disable Nagle, make NOTIFY packet go out right away */
val = 1;
(void)setsockopt(connection->fd, IPPROTO_TCP, TCP_NODELAY, (char *)&val,
sizeof(val));
/* Retrieve BGP packet type. */
stream_set_getp(s, BGP_MARKER_SIZE + 2);
type = stream_getc(s);
assert(type == BGP_MSG_NOTIFY);
/* Type should be notify. */
atomic_fetch_add_explicit(&peer->notify_out, 1, memory_order_relaxed);
/* Double start timer. */
peer->v_start *= 2;
/* Overflow check. */
if (peer->v_start >= (60 * 2))
peer->v_start = (60 * 2);
/*
* Handle Graceful Restart case where the state changes to
* Connect instead of Idle
*/
BGP_EVENT_ADD(connection, BGP_Stop);
stream_free(s);
}
/*
* Encapsulate an original BGP CEASE Notification into Hard Reset
*/
static uint8_t *bgp_notify_encapsulate_hard_reset(uint8_t code, uint8_t subcode,
uint8_t *data, size_t datalen)
{
uint8_t *message = XCALLOC(MTYPE_BGP_NOTIFICATION, datalen + 2);
/* ErrCode */
message[0] = code;
/* Subcode */
message[1] = subcode;
/* Data */
if (datalen)
memcpy(message + 2, data, datalen);
return message;
}
/*
* Decapsulate an original BGP CEASE Notification from Hard Reset
*/
struct bgp_notify bgp_notify_decapsulate_hard_reset(struct bgp_notify *notify)
{
struct bgp_notify bn = {};
bn.code = notify->raw_data[0];
bn.subcode = notify->raw_data[1];
bn.length = notify->length - 2;
bn.raw_data = XMALLOC(MTYPE_BGP_NOTIFICATION, bn.length);
memcpy(bn.raw_data, notify->raw_data + 2, bn.length);
return bn;
}
/* Check if Graceful-Restart N-bit is exchanged */
bool bgp_has_graceful_restart_notification(struct peer *peer)
{
return CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_RCV) &&
CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_ADV);
}
/*
* Check if to send BGP CEASE Notification/Hard Reset?
*/
bool bgp_notify_send_hard_reset(struct peer *peer, uint8_t code,
uint8_t subcode)
{
/* When the "N" bit has been exchanged, a Hard Reset message is used to
* indicate to the peer that the session is to be fully terminated.
*/
if (!bgp_has_graceful_restart_notification(peer))
return false;
/*
* https://datatracker.ietf.org/doc/html/rfc8538#section-5.1
*/
if (code == BGP_NOTIFY_CEASE) {
switch (subcode) {
case BGP_NOTIFY_CEASE_MAX_PREFIX:
case BGP_NOTIFY_CEASE_ADMIN_SHUTDOWN:
case BGP_NOTIFY_CEASE_PEER_UNCONFIG:
case BGP_NOTIFY_CEASE_HARD_RESET:
case BGP_NOTIFY_CEASE_BFD_DOWN:
return true;
case BGP_NOTIFY_CEASE_ADMIN_RESET:
/* Provide user control:
* `bgp hard-adminstrative-reset`
*/
if (CHECK_FLAG(peer->bgp->flags,
BGP_FLAG_HARD_ADMIN_RESET))
return true;
else
return false;
default:
break;
}
}
return false;
}
/*
* Check if received BGP CEASE Notification/Hard Reset?
*/
bool bgp_notify_received_hard_reset(struct peer *peer, uint8_t code,
uint8_t subcode)
{
/* When the "N" bit has been exchanged, a Hard Reset message is used to
* indicate to the peer that the session is to be fully terminated.
*/
if (!bgp_has_graceful_restart_notification(peer))
return false;
if (code == BGP_NOTIFY_CEASE && subcode == BGP_NOTIFY_CEASE_HARD_RESET)
return true;
return false;
}
/*
* Creates a BGP Notify and appends it to the peer's output queue.
*
* This function attempts to write the packet from the thread it is called
* from, to ensure the packet gets out ASAP.
*
* This function may be called from multiple threads. Since the function
* modifies I/O buffer(s) in the peer, these are locked for the duration of the
* call to prevent tampering from other threads.
*
* Delivery of the NOTIFICATION is attempted once and is best-effort. After
* return, the peer structure *must* be reset; no assumptions about session
* state are valid.
*
* @param peer
* @param code BGP error code
* @param sub_code BGP error subcode
* @param data Data portion
* @param datalen length of data portion
*/
static void bgp_notify_send_internal(struct peer_connection *connection,
uint8_t code, uint8_t sub_code,
uint8_t *data, size_t datalen,
bool use_curr)
{
struct stream *s;
struct peer *peer = connection->peer;
bool hard_reset = bgp_notify_send_hard_reset(peer, code, sub_code);
/* Lock I/O mutex to prevent other threads from pushing packets */
frr_mutex_lock_autounlock(&connection->io_mtx);
/* ============================================== */
/* Allocate new stream. */
s = stream_new(peer->max_packet_size);
/* Make notify packet. */
bgp_packet_set_marker(s, BGP_MSG_NOTIFY);
/* Check if we should send Hard Reset Notification or not */
if (hard_reset) {
uint8_t *hard_reset_message = bgp_notify_encapsulate_hard_reset(
code, sub_code, data, datalen);
/* Hard Reset encapsulates another NOTIFICATION message
* in its data portion.
*/
stream_putc(s, BGP_NOTIFY_CEASE);
stream_putc(s, BGP_NOTIFY_CEASE_HARD_RESET);
stream_write(s, hard_reset_message, datalen + 2);
XFREE(MTYPE_BGP_NOTIFICATION, hard_reset_message);
} else {
stream_putc(s, code);
stream_putc(s, sub_code);
if (data)
stream_write(s, data, datalen);
}
/* Set BGP packet length. */
bgp_packet_set_size(s);
/* wipe output buffer */
stream_fifo_clean(connection->obuf);
/*
* If possible, store last packet for debugging purposes. This check is
* in place because we are sometimes called with a doppelganger peer,
* who tends to have a plethora of fields nulled out.
*
* Some callers should not attempt this - the io pthread for example
* should not touch internals of the peer struct.
*/
if (use_curr && peer->curr) {
size_t packetsize = stream_get_endp(peer->curr);
assert(packetsize <= peer->max_packet_size);
if (peer->last_reset_cause)
stream_free(peer->last_reset_cause);
peer->last_reset_cause = stream_dup(peer->curr);
}
/* For debug */
{
struct bgp_notify bgp_notify;
int first = 0;
int i;
char c[4];
bgp_notify.code = code;
bgp_notify.subcode = sub_code;
bgp_notify.data = NULL;
bgp_notify.length = datalen;
bgp_notify.raw_data = data;
peer->notify.code = bgp_notify.code;
peer->notify.subcode = bgp_notify.subcode;
peer->notify.length = bgp_notify.length;
if (bgp_notify.length && data) {
bgp_notify.data = XMALLOC(MTYPE_BGP_NOTIFICATION,
bgp_notify.length * 3);
for (i = 0; i < bgp_notify.length; i++)
if (first) {
snprintf(c, sizeof(c), " %02x",
data[i]);
strlcat(bgp_notify.data, c,
bgp_notify.length);
} else {
first = 1;
snprintf(c, sizeof(c), "%02x", data[i]);