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mirror_frr/bgpd/bgp_updgrp_packet.c
Don Slice 1c875ddb57 bgpd: stop sending nexthop set by "route-map in" to eBGP peers 
Problem reported that when a "neighbor x.x.x.x route-map FOO in"
set a next-hop value, that modified next-hop value was also sent
to eBGP peers.  This is incorrect since bgp is expected to set
next-hop to self when sending to eBGP peers unless third party
next-hop on a shared segment is true.  This fix modifies the
behavior to stop sending the modified next-hop to eBGP peers
if the route-map was applied inbound on another peer.

Ticket: CM-26025
Signed-off-by: Don Slice <dslice@cumulusnetworks.com>
2019-09-25 13:54:39 -07:00

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/**
* bgp_updgrp_packet.c: BGP update group packet handling routines
*
* @copyright Copyright (C) 2014 Cumulus Networks, Inc.
*
* @author Avneesh Sachdev <avneesh@sproute.net>
* @author Rajesh Varadarajan <rajesh@sproute.net>
* @author Pradosh Mohapatra <pradosh@sproute.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 "prefix.h"
#include "thread.h"
#include "buffer.h"
#include "stream.h"
#include "command.h"
#include "sockunion.h"
#include "network.h"
#include "memory.h"
#include "filter.h"
#include "routemap.h"
#include "log.h"
#include "plist.h"
#include "linklist.h"
#include "workqueue.h"
#include "hash.h"
#include "queue.h"
#include "mpls.h"
#include "bgpd/bgpd.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_advertise.h"
#include "bgpd/bgp_updgrp.h"
#include "bgpd/bgp_nexthop.h"
#include "bgpd/bgp_nht.h"
#include "bgpd/bgp_mplsvpn.h"
#include "bgpd/bgp_label.h"
#include "bgpd/bgp_addpath.h"
/********************
* PRIVATE FUNCTIONS
********************/
/********************
* PUBLIC FUNCTIONS
********************/
struct bpacket *bpacket_alloc(void)
{
struct bpacket *pkt;
pkt = XCALLOC(MTYPE_BGP_PACKET, sizeof(struct bpacket));
return pkt;
}
void bpacket_free(struct bpacket *pkt)
{
if (pkt->buffer)
stream_free(pkt->buffer);
pkt->buffer = NULL;
XFREE(MTYPE_BGP_PACKET, pkt);
}
void bpacket_queue_init(struct bpacket_queue *q)
{
TAILQ_INIT(&(q->pkts));
}
/*
* bpacket_queue_sanity_check
*/
void bpacket_queue_sanity_check(struct bpacket_queue __attribute__((__unused__))
* q)
{
#if 0
struct bpacket *pkt;
pkt = bpacket_queue_last (q);
assert (pkt);
assert (!pkt->buffer);
/*
* Make sure the count of packets is correct.
*/
int num_pkts = 0;
pkt = bpacket_queue_first (q);
while (pkt)
{
num_pkts++;
if (num_pkts > q->curr_count)
assert (0);
pkt = TAILQ_NEXT (pkt, pkt_train);
}
assert (num_pkts == q->curr_count);
#endif
}
/*
* bpacket_queue_add_packet
*
* Internal function of bpacket_queue - and adds a
* packet entry to the end of the list.
*
* Users of bpacket_queue should use bpacket_queue_add instead.
*/
static void bpacket_queue_add_packet(struct bpacket_queue *q,
struct bpacket *pkt)
{
struct bpacket *last_pkt;
if (TAILQ_EMPTY(&(q->pkts)))
TAILQ_INSERT_TAIL(&(q->pkts), pkt, pkt_train);
else {
last_pkt = bpacket_queue_last(q);
TAILQ_INSERT_AFTER(&(q->pkts), last_pkt, pkt, pkt_train);
}
q->curr_count++;
if (q->hwm_count < q->curr_count)
q->hwm_count = q->curr_count;
}
/*
* Adds a packet to the bpacket_queue.
*
* The stream passed is consumed by this function. So, the caller should
* not free or use the stream after
* invoking this function.
*/
struct bpacket *bpacket_queue_add(struct bpacket_queue *q, struct stream *s,
struct bpacket_attr_vec_arr *vecarrp)
{
struct bpacket *pkt;
struct bpacket *last_pkt;
pkt = bpacket_alloc();
if (TAILQ_EMPTY(&(q->pkts))) {
pkt->ver = 1;
pkt->buffer = s;
if (vecarrp)
memcpy(&pkt->arr, vecarrp,
sizeof(struct bpacket_attr_vec_arr));
else
bpacket_attr_vec_arr_reset(&pkt->arr);
bpacket_queue_add_packet(q, pkt);
bpacket_queue_sanity_check(q);
return pkt;
}
/*
* Fill in the new information into the current sentinel and create a
* new sentinel.
*/
bpacket_queue_sanity_check(q);
last_pkt = bpacket_queue_last(q);
assert(last_pkt->buffer == NULL);
last_pkt->buffer = s;
if (vecarrp)
memcpy(&last_pkt->arr, vecarrp,
sizeof(struct bpacket_attr_vec_arr));
else
bpacket_attr_vec_arr_reset(&last_pkt->arr);
pkt->ver = last_pkt->ver;
pkt->ver++;
bpacket_queue_add_packet(q, pkt);
bpacket_queue_sanity_check(q);
return last_pkt;
}
struct bpacket *bpacket_queue_first(struct bpacket_queue *q)
{
return (TAILQ_FIRST(&(q->pkts)));
}
struct bpacket *bpacket_queue_last(struct bpacket_queue *q)
{
return TAILQ_LAST(&(q->pkts), pkt_queue);
}
struct bpacket *bpacket_queue_remove(struct bpacket_queue *q)
{
struct bpacket *first;
first = bpacket_queue_first(q);
if (first) {
TAILQ_REMOVE(&(q->pkts), first, pkt_train);
q->curr_count--;
}
return first;
}
unsigned int bpacket_queue_length(struct bpacket_queue *q)
{
return q->curr_count - 1;
}
unsigned int bpacket_queue_hwm_length(struct bpacket_queue *q)
{
return q->hwm_count - 1;
}
int bpacket_queue_is_full(struct bgp *bgp, struct bpacket_queue *q)
{
if (q->curr_count >= bgp->default_subgroup_pkt_queue_max)
return 1;
return 0;
}
void bpacket_add_peer(struct bpacket *pkt, struct peer_af *paf)
{
if (!pkt || !paf)
return;
LIST_INSERT_HEAD(&(pkt->peers), paf, pkt_train);
paf->next_pkt_to_send = pkt;
}
/*
* bpacket_queue_cleanup
*/
void bpacket_queue_cleanup(struct bpacket_queue *q)
{
struct bpacket *pkt;
while ((pkt = bpacket_queue_remove(q))) {
bpacket_free(pkt);
}
}
/*
* bpacket_queue_compact
*
* Delete packets that do not need to be transmitted to any peer from
* the queue.
*
* @return the number of packets deleted.
*/
static int bpacket_queue_compact(struct bpacket_queue *q)
{
int num_deleted;
struct bpacket *pkt, *removed_pkt;
num_deleted = 0;
while (1) {
pkt = bpacket_queue_first(q);
if (!pkt)
break;
/*
* Don't delete the sentinel.
*/
if (!pkt->buffer)
break;
if (!LIST_EMPTY(&(pkt->peers)))
break;
removed_pkt = bpacket_queue_remove(q);
assert(pkt == removed_pkt);
bpacket_free(removed_pkt);
num_deleted++;
}
bpacket_queue_sanity_check(q);
return num_deleted;
}
void bpacket_queue_advance_peer(struct peer_af *paf)
{
struct bpacket *pkt;
struct bpacket *old_pkt;
old_pkt = paf->next_pkt_to_send;
if (old_pkt->buffer == NULL)
/* Already at end of list */
return;
LIST_REMOVE(paf, pkt_train);
pkt = TAILQ_NEXT(old_pkt, pkt_train);
bpacket_add_peer(pkt, paf);
if (!bpacket_queue_compact(PAF_PKTQ(paf)))
return;
/*
* Deleted one or more packets. Check if we can now merge this
* peer's subgroup into another subgroup.
*/
update_subgroup_check_merge(paf->subgroup, "advanced peer in queue");
}
/*
* bpacket_queue_remove_peer
*
* Remove the peer from the packet queue of the subgroup it belongs
* to.
*/
void bpacket_queue_remove_peer(struct peer_af *paf)
{
struct bpacket_queue *q;
q = PAF_PKTQ(paf);
assert(q);
if (!q)
return;
LIST_REMOVE(paf, pkt_train);
paf->next_pkt_to_send = NULL;
bpacket_queue_compact(q);
}
unsigned int bpacket_queue_virtual_length(struct peer_af *paf)
{
struct bpacket *pkt;
struct bpacket *last;
struct bpacket_queue *q;
pkt = paf->next_pkt_to_send;
if (!pkt || (pkt->buffer == NULL))
/* Already at end of list */
return 0;
q = PAF_PKTQ(paf);
if (TAILQ_EMPTY(&(q->pkts)))
return 0;
last = TAILQ_LAST(&(q->pkts), pkt_queue);
if (last->ver >= pkt->ver)
return last->ver - pkt->ver;
/* sequence # rolled over */
return (UINT_MAX - pkt->ver + 1) + last->ver;
}
/*
* Dump the bpacket queue
*/
void bpacket_queue_show_vty(struct bpacket_queue *q, struct vty *vty)
{
struct bpacket *pkt;
struct peer_af *paf;
pkt = bpacket_queue_first(q);
while (pkt) {
vty_out(vty, " Packet %p ver %u buffer %p\n", pkt, pkt->ver,
pkt->buffer);
LIST_FOREACH (paf, &(pkt->peers), pkt_train) {
vty_out(vty, " - %s\n", paf->peer->host);
}
pkt = bpacket_next(pkt);
}
return;
}
struct stream *bpacket_reformat_for_peer(struct bpacket *pkt,
struct peer_af *paf)
{
struct stream *s = NULL;
bpacket_attr_vec *vec;
struct peer *peer;
char buf[BUFSIZ];
char buf2[BUFSIZ];
struct bgp_filter *filter;
s = stream_dup(pkt->buffer);
peer = PAF_PEER(paf);
vec = &pkt->arr.entries[BGP_ATTR_VEC_NH];
if (CHECK_FLAG(vec->flags, BPKT_ATTRVEC_FLAGS_UPDATED)) {
uint8_t nhlen;
afi_t nhafi;
int route_map_sets_nh;
nhlen = stream_getc_from(s, vec->offset);
filter = &peer->filter[paf->afi][paf->safi];
if (peer_cap_enhe(peer, paf->afi, paf->safi))
nhafi = AFI_IP6;
else
nhafi = BGP_NEXTHOP_AFI_FROM_NHLEN(nhlen);
if (nhafi == AFI_IP) {
struct in_addr v4nh, *mod_v4nh;
int nh_modified = 0;
size_t offset_nh = vec->offset + 1;
route_map_sets_nh =
(CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_IPV4_NH_CHANGED)
|| CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_PEER_ADDRESS));
switch (nhlen) {
case BGP_ATTR_NHLEN_IPV4:
break;
case BGP_ATTR_NHLEN_VPNV4:
offset_nh += 8;
break;
default:
/* TODO: handle IPv6 nexthops */
flog_warn(
EC_BGP_INVALID_NEXTHOP_LENGTH,
"%s: %s: invalid MP nexthop length (AFI IP): %u",
__func__, peer->host, nhlen);
stream_free(s);
return NULL;
}
stream_get_from(&v4nh, s, offset_nh, IPV4_MAX_BYTELEN);
mod_v4nh = &v4nh;
/*
* If route-map has set the nexthop, that is normally
* used; if it is specified as peer-address, the peering
* address is picked up. Otherwise, if NH is unavailable
* from attribute, the peering addr is picked up; the
* "NH unavailable" case also covers next-hop-self and
* some other scenarios - see subgroup_announce_check().
* In all other cases, use the nexthop carried in the
* attribute unless it is EBGP non-multiaccess and there
* is no next-hop-unchanged setting or the peer is EBGP
* and the route-map that changed the next-hop value
* was applied inbound rather than outbound. Updates to
* an EBGP peer should only modify the next-hop if it
* was set in an outbound route-map to that peer.
* Note: It is assumed route-map cannot set the nexthop
* to an invalid value.
*/
if (route_map_sets_nh
&& ((peer->sort != BGP_PEER_EBGP)
|| ROUTE_MAP_OUT(filter))) {
if (CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_PEER_ADDRESS)) {
mod_v4nh = &peer->nexthop.v4;
nh_modified = 1;
}
} else if (!v4nh.s_addr) {
mod_v4nh = &peer->nexthop.v4;
nh_modified = 1;
} else if (
peer->sort == BGP_PEER_EBGP
&& (bgp_multiaccess_check_v4(v4nh, peer) == 0)
&& !CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_UNCHANGED)
&& !peer_af_flag_check(
peer, paf->afi, paf->safi,
PEER_FLAG_NEXTHOP_UNCHANGED)) {
/* NOTE: not handling case where NH has new AFI
*/
mod_v4nh = &peer->nexthop.v4;
nh_modified = 1;
}
if (nh_modified) /* allow for VPN RD */
stream_put_in_addr_at(s, offset_nh, mod_v4nh);
if (bgp_debug_update(peer, NULL, NULL, 0))
zlog_debug("u%" PRIu64 ":s%" PRIu64
" %s send UPDATE w/ nexthop %s%s",
PAF_SUBGRP(paf)->update_group->id,
PAF_SUBGRP(paf)->id, peer->host,
inet_ntoa(*mod_v4nh),
(nhlen == 12 ? " and RD" : ""));
} else if (nhafi == AFI_IP6) {
struct in6_addr v6nhglobal, *mod_v6nhg;
struct in6_addr v6nhlocal, *mod_v6nhl;
int gnh_modified, lnh_modified;
size_t offset_nhglobal = vec->offset + 1;
size_t offset_nhlocal = vec->offset + 1;
gnh_modified = lnh_modified = 0;
mod_v6nhg = &v6nhglobal;
mod_v6nhl = &v6nhlocal;
route_map_sets_nh =
(CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_IPV6_GNH_CHANGED)
|| CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_PEER_ADDRESS));
/*
* The logic here is rather similar to that for IPv4,
* the
* additional work being to handle 1 or 2 nexthops.
* Also, 3rd
* party nexthop is not propagated for EBGP right now.
*/
switch (nhlen) {
case BGP_ATTR_NHLEN_IPV6_GLOBAL:
break;
case BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL:
offset_nhlocal += IPV6_MAX_BYTELEN;
break;
case BGP_ATTR_NHLEN_VPNV6_GLOBAL:
offset_nhglobal += 8;
break;
case BGP_ATTR_NHLEN_VPNV6_GLOBAL_AND_LL:
offset_nhglobal += 8;
offset_nhlocal += 8 * 2 + IPV6_MAX_BYTELEN;
break;
default:
/* TODO: handle IPv4 nexthops */
flog_warn(
EC_BGP_INVALID_NEXTHOP_LENGTH,
"%s: %s: invalid MP nexthop length (AFI IP6): %u",
__func__, peer->host, nhlen);
stream_free(s);
return NULL;
}
stream_get_from(&v6nhglobal, s, offset_nhglobal,
IPV6_MAX_BYTELEN);
/*
* Updates to an EBGP peer should only modify the
* next-hop if it was set in an outbound route-map
* to that peer.
*/
if (route_map_sets_nh
&& ((peer->sort != BGP_PEER_EBGP)
|| ROUTE_MAP_OUT(filter))) {
if (CHECK_FLAG(
vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_PEER_ADDRESS)) {
mod_v6nhg = &peer->nexthop.v6_global;
gnh_modified = 1;
}
} else if (IN6_IS_ADDR_UNSPECIFIED(&v6nhglobal)) {
mod_v6nhg = &peer->nexthop.v6_global;
gnh_modified = 1;
} else if (
(peer->sort == BGP_PEER_EBGP)
&& (!bgp_multiaccess_check_v6(v6nhglobal, peer))
&& !CHECK_FLAG(vec->flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_UNCHANGED)
&& !peer_af_flag_check(
peer, nhafi, paf->safi,
PEER_FLAG_NEXTHOP_UNCHANGED)) {
/* NOTE: not handling case where NH has new AFI
*/
mod_v6nhg = &peer->nexthop.v6_global;
gnh_modified = 1;
}
if (nhlen == BGP_ATTR_NHLEN_IPV6_GLOBAL_AND_LL
|| nhlen == BGP_ATTR_NHLEN_VPNV6_GLOBAL_AND_LL) {
stream_get_from(&v6nhlocal, s, offset_nhlocal,
IPV6_MAX_BYTELEN);
if (IN6_IS_ADDR_UNSPECIFIED(&v6nhlocal)) {
mod_v6nhl = &peer->nexthop.v6_local;
lnh_modified = 1;
}
}
if (gnh_modified)
stream_put_in6_addr_at(s, offset_nhglobal,
mod_v6nhg);
if (lnh_modified)
stream_put_in6_addr_at(s, offset_nhlocal,
mod_v6nhl);
if (bgp_debug_update(peer, NULL, NULL, 0)) {
if (nhlen == 32 || nhlen == 48)
zlog_debug(
"u%" PRIu64 ":s%" PRIu64
" %s send UPDATE w/ mp_nexthops %s, %s%s",
PAF_SUBGRP(paf)
->update_group->id,
PAF_SUBGRP(paf)->id, peer->host,
inet_ntop(AF_INET6, mod_v6nhg,
buf, BUFSIZ),
inet_ntop(AF_INET6, mod_v6nhl,
buf2, BUFSIZ),
(nhlen == 48 ? " and RD" : ""));
else
zlog_debug(
"u%" PRIu64 ":s%" PRIu64
" %s send UPDATE w/ mp_nexthop %s%s",
PAF_SUBGRP(paf)
->update_group->id,
PAF_SUBGRP(paf)->id, peer->host,
inet_ntop(AF_INET6, mod_v6nhg,
buf, BUFSIZ),
(nhlen == 24 ? " and RD" : ""));
}
} else if (paf->afi == AFI_L2VPN) {
struct in_addr v4nh, *mod_v4nh;
int nh_modified = 0;
stream_get_from(&v4nh, s, vec->offset + 1, 4);
mod_v4nh = &v4nh;
/* No route-map changes allowed for EVPN nexthops. */
if (!v4nh.s_addr) {
mod_v4nh = &peer->nexthop.v4;
nh_modified = 1;
}
if (nh_modified)
stream_put_in_addr_at(s, vec->offset + 1,
mod_v4nh);
if (bgp_debug_update(peer, NULL, NULL, 0))
zlog_debug("u%" PRIu64 ":s%" PRIu64
" %s send UPDATE w/ nexthop %s",
PAF_SUBGRP(paf)->update_group->id,
PAF_SUBGRP(paf)->id, peer->host,
inet_ntoa(*mod_v4nh));
}
}
return s;
}
/*
* Update the vecarr offsets to go beyond 'pos' bytes, i.e. add 'pos'
* to each offset.
*/
static void bpacket_attr_vec_arr_update(struct bpacket_attr_vec_arr *vecarr,
size_t pos)
{
int i;
if (!vecarr)
return;
for (i = 0; i < BGP_ATTR_VEC_MAX; i++)
vecarr->entries[i].offset += pos;
}
/*
* Return if there are packets to build for this subgroup.
*/
int subgroup_packets_to_build(struct update_subgroup *subgrp)
{
struct bgp_advertise *adv;
if (!subgrp)
return 0;
adv = bgp_adv_fifo_first(&subgrp->sync->withdraw);
if (adv)
return 1;
adv = bgp_adv_fifo_first(&subgrp->sync->update);
if (adv)
return 1;
return 0;
}
/* Make BGP update packet. */
struct bpacket *subgroup_update_packet(struct update_subgroup *subgrp)
{
struct bpacket_attr_vec_arr vecarr;
struct bpacket *pkt;
struct peer *peer;
struct stream *s;
struct stream *snlri;
struct stream *packet;
struct bgp_adj_out *adj;
struct bgp_advertise *adv;
struct bgp_node *rn = NULL;
struct bgp_path_info *path = NULL;
bgp_size_t total_attr_len = 0;
unsigned long attrlen_pos = 0;
size_t mpattrlen_pos = 0;
size_t mpattr_pos = 0;
afi_t afi;
safi_t safi;
int space_remaining = 0;
int space_needed = 0;
char send_attr_str[BUFSIZ];
int send_attr_printed = 0;
int num_pfx = 0;
int addpath_encode = 0;
int addpath_overhead = 0;
uint32_t addpath_tx_id = 0;
struct prefix_rd *prd = NULL;
mpls_label_t label = MPLS_INVALID_LABEL, *label_pnt = NULL;
uint32_t num_labels = 0;
if (!subgrp)
return NULL;
if (bpacket_queue_is_full(SUBGRP_INST(subgrp), SUBGRP_PKTQ(subgrp)))
return NULL;
peer = SUBGRP_PEER(subgrp);
afi = SUBGRP_AFI(subgrp);
safi = SUBGRP_SAFI(subgrp);
s = subgrp->work;
stream_reset(s);
snlri = subgrp->scratch;
stream_reset(snlri);
bpacket_attr_vec_arr_reset(&vecarr);
addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
addpath_overhead = addpath_encode ? BGP_ADDPATH_ID_LEN : 0;
adv = bgp_adv_fifo_first(&subgrp->sync->update);
while (adv) {
assert(adv->rn);
rn = adv->rn;
adj = adv->adj;
addpath_tx_id = adj->addpath_tx_id;
path = adv->pathi;
space_remaining = STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
- BGP_MAX_PACKET_SIZE_OVERFLOW;
space_needed =
BGP_NLRI_LENGTH + addpath_overhead
+ bgp_packet_mpattr_prefix_size(afi, safi, &rn->p);
/* When remaining space can't include NLRI and it's length. */
if (space_remaining < space_needed)
break;
/* If packet is empty, set attribute. */
if (stream_empty(s)) {
struct peer *from = NULL;
if (path)
from = path->peer;
/* 1: Write the BGP message header - 16 bytes marker, 2
* bytes length,
* one byte message type.
*/
bgp_packet_set_marker(s, BGP_MSG_UPDATE);
/* 2: withdrawn routes length */
stream_putw(s, 0);
/* 3: total attributes length - attrlen_pos stores the
* position */
attrlen_pos = stream_get_endp(s);
stream_putw(s, 0);
/* 4: if there is MP_REACH_NLRI attribute, that should
* be the first
* attribute, according to
* draft-ietf-idr-error-handling. Save the
* position.
*/
mpattr_pos = stream_get_endp(s);
/* 5: Encode all the attributes, except MP_REACH_NLRI
* attr. */
total_attr_len = bgp_packet_attribute(
NULL, peer, s, adv->baa->attr, &vecarr, NULL,
afi, safi, from, NULL, NULL, 0, 0, 0);
space_remaining =
STREAM_CONCAT_REMAIN(s, snlri, STREAM_SIZE(s))
- BGP_MAX_PACKET_SIZE_OVERFLOW;
space_needed = BGP_NLRI_LENGTH + addpath_overhead
+ bgp_packet_mpattr_prefix_size(
afi, safi, &rn->p);
/* If the attributes alone do not leave any room for
* NLRI then
* return */
if (space_remaining < space_needed) {
flog_err(
EC_BGP_UPDGRP_ATTR_LEN,
"u%" PRIu64 ":s%" PRIu64
" attributes too long, cannot send UPDATE",
subgrp->update_group->id, subgrp->id);
/* Flush the FIFO update queue */
while (adv)
adv = bgp_advertise_clean_subgroup(
subgrp, adj);
return NULL;
}
if (BGP_DEBUG(update, UPDATE_OUT)
|| BGP_DEBUG(update, UPDATE_PREFIX)) {
memset(send_attr_str, 0, BUFSIZ);
send_attr_printed = 0;
bgp_dump_attr(adv->baa->attr, send_attr_str,
BUFSIZ);
}
}
if ((afi == AFI_IP && safi == SAFI_UNICAST)
&& !peer_cap_enhe(peer, afi, safi))
stream_put_prefix_addpath(s, &rn->p, addpath_encode,
addpath_tx_id);
else {
/* Encode the prefix in MP_REACH_NLRI attribute */
if (rn->prn)
prd = (struct prefix_rd *)&rn->prn->p;
if (safi == SAFI_LABELED_UNICAST) {
label = bgp_adv_label(rn, path, peer, afi,
safi);
label_pnt = &label;
num_labels = 1;
} else if (path && path->extra) {
label_pnt = &path->extra->label[0];
num_labels = path->extra->num_labels;
}
if (stream_empty(snlri))
mpattrlen_pos = bgp_packet_mpattr_start(
snlri, peer, afi, safi, &vecarr,
adv->baa->attr);
bgp_packet_mpattr_prefix(snlri, afi, safi, &rn->p, prd,
label_pnt, num_labels,
addpath_encode, addpath_tx_id,
adv->baa->attr);
}
num_pfx++;
if (bgp_debug_update(NULL, &rn->p, subgrp->update_group, 0)) {
char pfx_buf[BGP_PRD_PATH_STRLEN];
if (!send_attr_printed) {
zlog_debug("u%" PRIu64 ":s%" PRIu64
" send UPDATE w/ attr: %s",
subgrp->update_group->id, subgrp->id,
send_attr_str);
if (!stream_empty(snlri)) {
iana_afi_t pkt_afi;
iana_safi_t pkt_safi;
pkt_afi = afi_int2iana(afi);
pkt_safi = safi_int2iana(safi);
zlog_debug(
"u%" PRIu64 ":s%" PRIu64
" send MP_REACH for afi/safi %d/%d",
subgrp->update_group->id,
subgrp->id, pkt_afi, pkt_safi);
}
send_attr_printed = 1;
}
bgp_debug_rdpfxpath2str(afi, safi, prd, &rn->p,
label_pnt, num_labels,
addpath_encode, addpath_tx_id,
pfx_buf, sizeof(pfx_buf));
zlog_debug("u%" PRIu64 ":s%" PRIu64 " send UPDATE %s",
subgrp->update_group->id, subgrp->id,
pfx_buf);
}
/* Synchnorize attribute. */
if (adj->attr)
bgp_attr_unintern(&adj->attr);
else
subgrp->scount++;
adj->attr = bgp_attr_intern(adv->baa->attr);
adv = bgp_advertise_clean_subgroup(subgrp, adj);
}
if (!stream_empty(s)) {
if (!stream_empty(snlri)) {
bgp_packet_mpattr_end(snlri, mpattrlen_pos);
total_attr_len += stream_get_endp(snlri);
}
/* set the total attribute length correctly */
stream_putw_at(s, attrlen_pos, total_attr_len);
if (!stream_empty(snlri)) {
packet = stream_dupcat(s, snlri, mpattr_pos);
bpacket_attr_vec_arr_update(&vecarr, mpattr_pos);
} else
packet = stream_dup(s);
bgp_packet_set_size(packet);
if (bgp_debug_update(NULL, NULL, subgrp->update_group, 0))
zlog_debug("u%" PRIu64 ":s%" PRIu64
" send UPDATE len %zd numpfx %d",
subgrp->update_group->id, subgrp->id,
(stream_get_endp(packet)
- stream_get_getp(packet)),
num_pfx);
pkt = bpacket_queue_add(SUBGRP_PKTQ(subgrp), packet, &vecarr);
stream_reset(s);
stream_reset(snlri);
return pkt;
}
return NULL;
}
/* Make BGP withdraw packet. */
/* For ipv4 unicast:
16-octet marker | 2-octet length | 1-octet type |
2-octet withdrawn route length | withdrawn prefixes | 2-octet attrlen (=0)
*/
/* For other afi/safis:
16-octet marker | 2-octet length | 1-octet type |
2-octet withdrawn route length (=0) | 2-octet attrlen |
mp_unreach attr type | attr len | afi | safi | withdrawn prefixes
*/
struct bpacket *subgroup_withdraw_packet(struct update_subgroup *subgrp)
{
struct bpacket *pkt;
struct stream *s;
struct bgp_adj_out *adj;
struct bgp_advertise *adv;
struct peer *peer;
struct bgp_node *rn;
bgp_size_t unfeasible_len;
bgp_size_t total_attr_len;
size_t mp_start = 0;
size_t attrlen_pos = 0;
size_t mplen_pos = 0;
uint8_t first_time = 1;
afi_t afi;
safi_t safi;
int space_remaining = 0;
int space_needed = 0;
int num_pfx = 0;
int addpath_encode = 0;
int addpath_overhead = 0;
uint32_t addpath_tx_id = 0;
struct prefix_rd *prd = NULL;
if (!subgrp)
return NULL;
if (bpacket_queue_is_full(SUBGRP_INST(subgrp), SUBGRP_PKTQ(subgrp)))
return NULL;
peer = SUBGRP_PEER(subgrp);
afi = SUBGRP_AFI(subgrp);
safi = SUBGRP_SAFI(subgrp);
s = subgrp->work;
stream_reset(s);
addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
addpath_overhead = addpath_encode ? BGP_ADDPATH_ID_LEN : 0;
while ((adv = bgp_adv_fifo_first(&subgrp->sync->withdraw)) != NULL) {
assert(adv->rn);
adj = adv->adj;
rn = adv->rn;
addpath_tx_id = adj->addpath_tx_id;
space_remaining =
STREAM_WRITEABLE(s) - BGP_MAX_PACKET_SIZE_OVERFLOW;
space_needed =
BGP_NLRI_LENGTH + addpath_overhead + BGP_TOTAL_ATTR_LEN
+ bgp_packet_mpattr_prefix_size(afi, safi, &rn->p);
if (space_remaining < space_needed)
break;
if (stream_empty(s)) {
bgp_packet_set_marker(s, BGP_MSG_UPDATE);
stream_putw(s, 0); /* unfeasible routes length */
} else
first_time = 0;
if (afi == AFI_IP && safi == SAFI_UNICAST
&& !peer_cap_enhe(peer, afi, safi))
stream_put_prefix_addpath(s, &rn->p, addpath_encode,
addpath_tx_id);
else {
if (rn->prn)
prd = (struct prefix_rd *)&rn->prn->p;
/* If first time, format the MP_UNREACH header */
if (first_time) {
iana_afi_t pkt_afi;
iana_safi_t pkt_safi;
pkt_afi = afi_int2iana(afi);
pkt_safi = safi_int2iana(safi);
attrlen_pos = stream_get_endp(s);
/* total attr length = 0 for now. reevaluate
* later */
stream_putw(s, 0);
mp_start = stream_get_endp(s);
mplen_pos = bgp_packet_mpunreach_start(s, afi,
safi);
if (bgp_debug_update(NULL, NULL,
subgrp->update_group, 0))
zlog_debug(
"u%" PRIu64 ":s%" PRIu64
" send MP_UNREACH for afi/safi %d/%d",
subgrp->update_group->id,
subgrp->id, pkt_afi, pkt_safi);
}
bgp_packet_mpunreach_prefix(s, &rn->p, afi, safi, prd,
NULL, 0, addpath_encode,
addpath_tx_id, NULL);
}
num_pfx++;
if (bgp_debug_update(NULL, &rn->p, subgrp->update_group, 0)) {
char pfx_buf[BGP_PRD_PATH_STRLEN];
bgp_debug_rdpfxpath2str(afi, safi, prd, &rn->p, NULL, 0,
addpath_encode, addpath_tx_id,
pfx_buf, sizeof(pfx_buf));
zlog_debug("u%" PRIu64 ":s%" PRIu64
" send UPDATE %s -- unreachable",
subgrp->update_group->id, subgrp->id,
pfx_buf);
}
subgrp->scount--;
bgp_adj_out_remove_subgroup(rn, adj, subgrp);
bgp_unlock_node(rn);
}
if (!stream_empty(s)) {
if (afi == AFI_IP && safi == SAFI_UNICAST
&& !peer_cap_enhe(peer, afi, safi)) {
unfeasible_len = stream_get_endp(s) - BGP_HEADER_SIZE
- BGP_UNFEASIBLE_LEN;
stream_putw_at(s, BGP_HEADER_SIZE, unfeasible_len);
stream_putw(s, 0);
} else {
/* Set the mp_unreach attr's length */
bgp_packet_mpunreach_end(s, mplen_pos);
/* Set total path attribute length. */
total_attr_len = stream_get_endp(s) - mp_start;
stream_putw_at(s, attrlen_pos, total_attr_len);
}
bgp_packet_set_size(s);
if (bgp_debug_update(NULL, NULL, subgrp->update_group, 0))
zlog_debug("u%" PRIu64 ":s%" PRIu64
" send UPDATE (withdraw) len %zd numpfx %d",
subgrp->update_group->id, subgrp->id,
(stream_get_endp(s) - stream_get_getp(s)),
num_pfx);
pkt = bpacket_queue_add(SUBGRP_PKTQ(subgrp), stream_dup(s),
NULL);
stream_reset(s);
return pkt;
}
return NULL;
}
void subgroup_default_update_packet(struct update_subgroup *subgrp,
struct attr *attr, struct peer *from)
{
struct stream *s;
struct peer *peer;
struct prefix p;
unsigned long pos;
bgp_size_t total_attr_len;
afi_t afi;
safi_t safi;
struct bpacket_attr_vec_arr vecarr;
int addpath_encode = 0;
if (DISABLE_BGP_ANNOUNCE)
return;
if (!subgrp)
return;
peer = SUBGRP_PEER(subgrp);
afi = SUBGRP_AFI(subgrp);
safi = SUBGRP_SAFI(subgrp);
bpacket_attr_vec_arr_reset(&vecarr);
addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
memset(&p, 0, sizeof(p));
p.family = afi2family(afi);
p.prefixlen = 0;
/* Logging the attribute. */
if (bgp_debug_update(NULL, &p, subgrp->update_group, 0)) {
char attrstr[BUFSIZ];
char buf[PREFIX_STRLEN];
/* ' with addpath ID ' 17
* max strlen of uint32 + 10
* +/- (just in case) + 1
* null terminator + 1
* ============================ 29 */
char tx_id_buf[30];
attrstr[0] = '\0';
bgp_dump_attr(attr, attrstr, BUFSIZ);
if (addpath_encode)
snprintf(tx_id_buf, sizeof(tx_id_buf),
" with addpath ID %u",
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
else
tx_id_buf[0] = '\0';
zlog_debug("u%" PRIu64 ":s%" PRIu64 " send UPDATE %s%s %s",
(SUBGRP_UPDGRP(subgrp))->id, subgrp->id,
prefix2str(&p, buf, sizeof(buf)), tx_id_buf,
attrstr);
}
s = stream_new(BGP_MAX_PACKET_SIZE);
/* Make BGP update packet. */
bgp_packet_set_marker(s, BGP_MSG_UPDATE);
/* Unfeasible Routes Length. */
stream_putw(s, 0);
/* Make place for total attribute length. */
pos = stream_get_endp(s);
stream_putw(s, 0);
total_attr_len = bgp_packet_attribute(
NULL, peer, s, attr, &vecarr, &p, afi, safi, from, NULL, NULL,
0, addpath_encode, BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
/* Set Total Path Attribute Length. */
stream_putw_at(s, pos, total_attr_len);
/* NLRI set. */
if (p.family == AF_INET && safi == SAFI_UNICAST
&& !peer_cap_enhe(peer, afi, safi))
stream_put_prefix_addpath(
s, &p, addpath_encode,
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
/* Set size. */
bgp_packet_set_size(s);
(void)bpacket_queue_add(SUBGRP_PKTQ(subgrp), s, &vecarr);
subgroup_trigger_write(subgrp);
}
void subgroup_default_withdraw_packet(struct update_subgroup *subgrp)
{
struct peer *peer;
struct stream *s;
struct prefix p;
unsigned long attrlen_pos = 0;
unsigned long cp;
bgp_size_t unfeasible_len;
bgp_size_t total_attr_len = 0;
size_t mp_start = 0;
size_t mplen_pos = 0;
afi_t afi;
safi_t safi;
int addpath_encode = 0;
if (DISABLE_BGP_ANNOUNCE)
return;
peer = SUBGRP_PEER(subgrp);
afi = SUBGRP_AFI(subgrp);
safi = SUBGRP_SAFI(subgrp);
addpath_encode = bgp_addpath_encode_tx(peer, afi, safi);
memset(&p, 0, sizeof(p));
p.family = afi2family(afi);
p.prefixlen = 0;
if (bgp_debug_update(NULL, &p, subgrp->update_group, 0)) {
char buf[PREFIX_STRLEN];
/* ' with addpath ID ' 17
* max strlen of uint32 + 10
* +/- (just in case) + 1
* null terminator + 1
* ============================ 29 */
char tx_id_buf[30];
if (addpath_encode)
snprintf(tx_id_buf, sizeof(tx_id_buf),
" with addpath ID %u",
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
zlog_debug("u%" PRIu64 ":s%" PRIu64
" send UPDATE %s%s -- unreachable",
(SUBGRP_UPDGRP(subgrp))->id, subgrp->id,
prefix2str(&p, buf, sizeof(buf)), tx_id_buf);
}
s = stream_new(BGP_MAX_PACKET_SIZE);
/* Make BGP update packet. */
bgp_packet_set_marker(s, BGP_MSG_UPDATE);
/* Unfeasible Routes Length. */;
cp = stream_get_endp(s);
stream_putw(s, 0);
/* Withdrawn Routes. */
if (p.family == AF_INET && safi == SAFI_UNICAST
&& !peer_cap_enhe(peer, afi, safi)) {
stream_put_prefix_addpath(
s, &p, addpath_encode,
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE);
unfeasible_len = stream_get_endp(s) - cp - 2;
/* Set unfeasible len. */
stream_putw_at(s, cp, unfeasible_len);
/* Set total path attribute length. */
stream_putw(s, 0);
} else {
attrlen_pos = stream_get_endp(s);
stream_putw(s, 0);
mp_start = stream_get_endp(s);
mplen_pos = bgp_packet_mpunreach_start(s, afi, safi);
bgp_packet_mpunreach_prefix(
s, &p, afi, safi, NULL, NULL, 0, addpath_encode,
BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE, NULL);
/* Set the mp_unreach attr's length */
bgp_packet_mpunreach_end(s, mplen_pos);
/* Set total path attribute length. */
total_attr_len = stream_get_endp(s) - mp_start;
stream_putw_at(s, attrlen_pos, total_attr_len);
}
bgp_packet_set_size(s);
(void)bpacket_queue_add(SUBGRP_PKTQ(subgrp), s, NULL);
subgroup_trigger_write(subgrp);
}
static void
bpacket_vec_arr_inherit_attr_flags(struct bpacket_attr_vec_arr *vecarr,
bpacket_attr_vec_type type,
struct attr *attr)
{
if (CHECK_FLAG(attr->rmap_change_flags,
BATTR_RMAP_NEXTHOP_PEER_ADDRESS))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_PEER_ADDRESS);
if (CHECK_FLAG(attr->rmap_change_flags, BATTR_REFLECTED))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_REFLECTED);
if (CHECK_FLAG(attr->rmap_change_flags, BATTR_RMAP_NEXTHOP_UNCHANGED))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_RMAP_NH_UNCHANGED);
if (CHECK_FLAG(attr->rmap_change_flags, BATTR_RMAP_IPV4_NHOP_CHANGED))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_RMAP_IPV4_NH_CHANGED);
if (CHECK_FLAG(attr->rmap_change_flags,
BATTR_RMAP_IPV6_GLOBAL_NHOP_CHANGED))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_RMAP_IPV6_GNH_CHANGED);
if (CHECK_FLAG(attr->rmap_change_flags,
BATTR_RMAP_IPV6_LL_NHOP_CHANGED))
SET_FLAG(vecarr->entries[BGP_ATTR_VEC_NH].flags,
BPKT_ATTRVEC_FLAGS_RMAP_IPV6_LNH_CHANGED);
}
/* Reset the Attributes vector array. The vector array is used to override
* certain output parameters in the packet for a particular peer
*/
void bpacket_attr_vec_arr_reset(struct bpacket_attr_vec_arr *vecarr)
{
int i;
if (!vecarr)
return;
i = 0;
while (i < BGP_ATTR_VEC_MAX) {
vecarr->entries[i].flags = 0;
vecarr->entries[i].offset = 0;
i++;
}
}
/* Setup a particular node entry in the vecarr */
void bpacket_attr_vec_arr_set_vec(struct bpacket_attr_vec_arr *vecarr,
bpacket_attr_vec_type type, struct stream *s,
struct attr *attr)
{
if (!vecarr)
return;
assert(type < BGP_ATTR_VEC_MAX);
SET_FLAG(vecarr->entries[type].flags, BPKT_ATTRVEC_FLAGS_UPDATED);
vecarr->entries[type].offset = stream_get_endp(s);
if (attr)
bpacket_vec_arr_inherit_attr_flags(vecarr, type, attr);
}
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