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/* BGP network related fucntions
* Copyright (C) 1999 Kunihiro Ishiguro
*
* 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 "thread.h"
#include "sockunion.h"
#include "sockopt.h"
#include "memory.h"
#include "log.h"
#include "if.h"
#include "prefix.h"
#include "command.h"
#include "privs.h"
#include "linklist.h"
#include "network.h"
#include "queue.h"
#include "hash.h"
#include "filter.h"
#include "ns.h"
#include "lib_errors.h"
#include "nexthop.h"
#include "bgpd/bgpd.h"
#include "bgpd/bgp_open.h"
#include "bgpd/bgp_fsm.h"
#include "bgpd/bgp_attr.h"
#include "bgpd/bgp_debug.h"
#include "bgpd/bgp_errors.h"
#include "bgpd/bgp_network.h"
#include "bgpd/bgp_zebra.h"
extern struct zebra_privs_t bgpd_privs;
static char *bgp_get_bound_name(struct peer *peer);
/* BGP listening socket. */
struct bgp_listener {
int fd;
union sockunion su;
struct thread *thread;
struct bgp *bgp;
};
/*
* Set MD5 key for the socket, for the given IPv4 peer address.
* If the password is NULL or zero-length, the option will be disabled.
*/
static int bgp_md5_set_socket(int socket, union sockunion *su,
const char *password)
{
int ret = -1;
int en = ENOSYS;
#if HAVE_DECL_TCP_MD5SIG
union sockunion su2;
#endif /* HAVE_TCP_MD5SIG */
assert(socket >= 0);
#if HAVE_DECL_TCP_MD5SIG
/* Ensure there is no extraneous port information. */
memcpy(&su2, su, sizeof(union sockunion));
if (su2.sa.sa_family == AF_INET)
su2.sin.sin_port = 0;
else
su2.sin6.sin6_port = 0;
ret = sockopt_tcp_signature(socket, &su2, password);
en = errno;
#endif /* HAVE_TCP_MD5SIG */
if (ret < 0)
flog_warn(EC_BGP_NO_TCP_MD5,
"can't set TCP_MD5SIG option on socket %d: %s",
socket, safe_strerror(en));
return ret;
}
/* Helper for bgp_connect */
static int bgp_md5_set_connect(int socket, union sockunion *su,
const char *password)
{
int ret = -1;
#if HAVE_DECL_TCP_MD5SIG
frr_elevate_privs(&bgpd_privs) {
ret = bgp_md5_set_socket(socket, su, password);
}
#endif /* HAVE_TCP_MD5SIG */
return ret;
}
static int bgp_md5_set_password(struct peer *peer, const char *password)
{
struct listnode *node;
int ret = 0;
struct bgp_listener *listener;
frr_elevate_privs(&bgpd_privs) {
/* Set or unset the password on the listen socket(s). Outbound
* connections are taken care of in bgp_connect() below.
*/
for (ALL_LIST_ELEMENTS_RO(bm->listen_sockets, node, listener))
if (listener->su.sa.sa_family
== peer->su.sa.sa_family) {
ret = bgp_md5_set_socket(listener->fd,
&peer->su, password);
break;
}
}
return ret;
}
int bgp_md5_set(struct peer *peer)
{
/* Set the password from listen socket. */
return bgp_md5_set_password(peer, peer->password);
}
int bgp_md5_unset(struct peer *peer)
{
/* Unset the password from listen socket. */
return bgp_md5_set_password(peer, NULL);
}
int bgp_set_socket_ttl(struct peer *peer, int bgp_sock)
{
char buf[INET_ADDRSTRLEN];
int ret = 0;
/* In case of peer is EBGP, we should set TTL for this connection. */
if (!peer->gtsm_hops && (peer_sort(peer) == BGP_PEER_EBGP)) {
ret = sockopt_ttl(peer->su.sa.sa_family, bgp_sock, peer->ttl);
if (ret) {
flog_err(
EC_LIB_SOCKET,
"%s: Can't set TxTTL on peer (rtrid %s) socket, err = %d",
__func__,
inet_ntop(AF_INET, &peer->remote_id, buf,
sizeof(buf)),
errno);
return ret;
}
} else if (peer->gtsm_hops) {
/* On Linux, setting minttl without setting ttl seems to mess
with the
outgoing ttl. Therefore setting both.
*/
ret = sockopt_ttl(peer->su.sa.sa_family, bgp_sock, MAXTTL);
if (ret) {
flog_err(
EC_LIB_SOCKET,
"%s: Can't set TxTTL on peer (rtrid %s) socket, err = %d",
__func__,
inet_ntop(AF_INET, &peer->remote_id, buf,
sizeof(buf)),
errno);
return ret;
}
ret = sockopt_minttl(peer->su.sa.sa_family, bgp_sock,
MAXTTL + 1 - peer->gtsm_hops);
if (ret) {
flog_err(
EC_LIB_SOCKET,
"%s: Can't set MinTTL on peer (rtrid %s) socket, err = %d",
__func__,
inet_ntop(AF_INET, &peer->remote_id, buf,
sizeof(buf)),
errno);
return ret;
}
}
return ret;
}
/*
* Obtain the BGP instance that the incoming connection should be processed
* against. This is important because more than one VRF could be using the
* same IP address space. The instance is got by obtaining the device to
* which the incoming connection is bound to. This could either be a VRF
* or it could be an interface, which in turn determines the VRF.
*/
static int bgp_get_instance_for_inc_conn(int sock, struct bgp **bgp_inst)
{
#ifndef SO_BINDTODEVICE
/* only Linux has SO_BINDTODEVICE, but we're in Linux-specific code here
* anyway since the assumption is that the interface name returned by
* getsockopt() is useful in identifying the VRF, particularly with
* Linux's
* VRF l3master device. The whole mechanism is specific to Linux, so...
* when other platforms add VRF support, this will need handling here as
* well. (or, some restructuring) */
*bgp_inst = bgp_get_default();
return !*bgp_inst;
#else
char name[VRF_NAMSIZ + 1];
socklen_t name_len = VRF_NAMSIZ;
struct bgp *bgp;
int rc;
struct listnode *node, *nnode;
*bgp_inst = NULL;
name[0] = '\0';
rc = getsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, name, &name_len);
if (rc != 0) {
#if defined(HAVE_CUMULUS)
flog_err(EC_LIB_SOCKET,
"[Error] BGP SO_BINDTODEVICE get failed (%s), sock %d",
safe_strerror(errno), sock);
return -1;
#endif
}
if (!strlen(name)) {
*bgp_inst = bgp_get_default();
return 0; /* default instance. */
}
/* First try match to instance; if that fails, check for interfaces. */
bgp = bgp_lookup_by_name(name);
if (bgp) {
if (!bgp->vrf_id) // unexpected
return -1;
*bgp_inst = bgp;
return 0;
}
/* TODO - This will be optimized once interfaces move into the NS */
for (ALL_LIST_ELEMENTS(bm->bgp, node, nnode, bgp)) {
struct interface *ifp;
if (bgp->inst_type == BGP_INSTANCE_TYPE_VIEW)
continue;
ifp = if_lookup_by_name(name, bgp->vrf_id);
if (ifp) {
*bgp_inst = bgp;
return 0;
}
}
/* We didn't match to either an instance or an interface. */
return -1;
#endif
}
/* Accept bgp connection. */
static int bgp_accept(struct thread *thread)
{
int bgp_sock;
int accept_sock;
union sockunion su;
struct bgp_listener *listener = THREAD_ARG(thread);
struct peer *peer;
struct peer *peer1;
char buf[SU_ADDRSTRLEN];
struct bgp *bgp = NULL;
sockunion_init(&su);
/* Register accept thread. */
accept_sock = THREAD_FD(thread);
if (accept_sock < 0) {
flog_err_sys(EC_LIB_SOCKET, "accept_sock is nevative value %d",
accept_sock);
return -1;
}
listener->thread = NULL;
thread_add_read(bm->master, bgp_accept, listener, accept_sock,
&listener->thread);
/* Accept client connection. */
bgp_sock = sockunion_accept(accept_sock, &su);
if (bgp_sock < 0) {
flog_err_sys(EC_LIB_SOCKET,
"[Error] BGP socket accept failed (%s)",
safe_strerror(errno));
return -1;
}
set_nonblocking(bgp_sock);
/* Obtain BGP instance this connection is meant for.
* - if it is a VRF netns sock, then BGP is in listener structure
* - otherwise, the bgp instance need to be demultiplexed
*/
if (listener->bgp)
bgp = listener->bgp;
else if (bgp_get_instance_for_inc_conn(bgp_sock, &bgp)) {
if (bgp_debug_neighbor_events(NULL))
zlog_debug(
"[Event] Could not get instance for incoming conn from %s",
inet_sutop(&su, buf));
close(bgp_sock);
return -1;
}
/* Set socket send buffer size */
setsockopt_so_sendbuf(bgp_sock, BGP_SOCKET_SNDBUF_SIZE);
/* Check remote IP address */
peer1 = peer_lookup(bgp, &su);
if (!peer1) {
peer1 = peer_lookup_dynamic_neighbor(bgp, &su);
if (peer1) {
/* Dynamic neighbor has been created, let it proceed */
peer1->fd = bgp_sock;
bgp_fsm_change_status(peer1, Active);
BGP_TIMER_OFF(
peer1->t_start); /* created in peer_create() */
if (peer_active(peer1))
BGP_EVENT_ADD(peer1, TCP_connection_open);
return 0;
}
}
if (!peer1) {
if (bgp_debug_neighbor_events(NULL)) {
zlog_debug(
"[Event] %s connection rejected - not configured"
" and not valid for dynamic",
inet_sutop(&su, buf));
}
close(bgp_sock);
return -1;
}
if (CHECK_FLAG(peer1->flags, PEER_FLAG_SHUTDOWN)) {
if (bgp_debug_neighbor_events(peer1))
zlog_debug(
"[Event] connection from %s rejected due to admin shutdown",
inet_sutop(&su, buf));
close(bgp_sock);
return -1;
}
/*
* Do not accept incoming connections in Clearing state. This can result
* in incorect state transitions - e.g., the connection goes back to
* Established and then the Clearing_Completed event is generated. Also,
* block incoming connection in Deleted state.
*/
if (peer1->status == Clearing || peer1->status == Deleted) {
if (bgp_debug_neighbor_events(peer1))
zlog_debug(
"[Event] Closing incoming conn for %s (%p) state %d",
peer1->host, peer1, peer1->status);
close(bgp_sock);
return -1;
}
/* Check that at least one AF is activated for the peer. */
if (!peer_active(peer1)) {
if (bgp_debug_neighbor_events(peer1))
zlog_debug(
"%s - incoming conn rejected - no AF activated for peer",
peer1->host);
close(bgp_sock);
return -1;
}
if (bgp_debug_neighbor_events(peer1))
zlog_debug("[Event] BGP connection from host %s fd %d",
inet_sutop(&su, buf), bgp_sock);
if (peer1->doppelganger) {
/* We have an existing connection. Kill the existing one and run
with this one.
*/
if (bgp_debug_neighbor_events(peer1))
zlog_debug(
"[Event] New active connection from peer %s, Killing"
" previous active connection",
peer1->host);
peer_delete(peer1->doppelganger);
}
if (bgp_set_socket_ttl(peer1, bgp_sock) < 0)
if (bgp_debug_neighbor_events(peer1))
zlog_debug(
"[Event] Unable to set min/max TTL on peer %s, Continuing",
peer1->host);
peer = peer_create(&su, peer1->conf_if, peer1->bgp, peer1->local_as,
peer1->as, peer1->as_type, 0, 0, NULL);
hash_release(peer->bgp->peerhash, peer);
hash_get(peer->bgp->peerhash, peer, hash_alloc_intern);
peer_xfer_config(peer, peer1);
UNSET_FLAG(peer->flags, PEER_FLAG_CONFIG_NODE);
peer->doppelganger = peer1;
peer1->doppelganger = peer;
peer->fd = bgp_sock;
vrf_bind(peer->bgp->vrf_id, bgp_sock, bgp_get_bound_name(peer));
bgp_fsm_change_status(peer, Active);
BGP_TIMER_OFF(peer->t_start); /* created in peer_create() */
SET_FLAG(peer->sflags, PEER_STATUS_ACCEPT_PEER);
/* Make dummy peer until read Open packet. */
if (peer1->status == Established
&& CHECK_FLAG(peer1->sflags, PEER_STATUS_NSF_MODE)) {
/* If we have an existing established connection with graceful
* restart
* capability announced with one or more address families, then
* drop
* existing established connection and move state to connect.
*/
peer1->last_reset = PEER_DOWN_NSF_CLOSE_SESSION;
SET_FLAG(peer1->sflags, PEER_STATUS_NSF_WAIT);
bgp_event_update(peer1, TCP_connection_closed);
}
if (peer_active(peer)) {
BGP_EVENT_ADD(peer, TCP_connection_open);
}
return 0;
}
/* BGP socket bind. */
static char *bgp_get_bound_name(struct peer *peer)
{
char *name = NULL;
if (!peer)
return NULL;
if ((peer->bgp->vrf_id == VRF_DEFAULT) && !peer->ifname
&& !peer->conf_if)
return NULL;
if (peer->su.sa.sa_family != AF_INET
&& peer->su.sa.sa_family != AF_INET6)
return NULL; // unexpected
/* For IPv6 peering, interface (unnumbered or link-local with interface)
* takes precedence over VRF. For IPv4 peering, explicit interface or
* VRF are the situations to bind.
*/
if (peer->su.sa.sa_family == AF_INET6)
name = (peer->conf_if ? peer->conf_if
: (peer->ifname ? peer->ifname
: peer->bgp->name));
else
name = peer->ifname ? peer->ifname : peer->bgp->name;
return name;
}
static int bgp_update_address(struct interface *ifp, const union sockunion *dst,
union sockunion *addr)
{
struct prefix *p, *sel, d;
struct connected *connected;
struct listnode *node;
int common;
sockunion2hostprefix(dst, &d);
sel = NULL;
common = -1;
for (ALL_LIST_ELEMENTS_RO(ifp->connected, node, connected)) {
p = connected->address;
if (p->family != d.family)
continue;
if (prefix_common_bits(p, &d) > common) {
sel = p;
common = prefix_common_bits(sel, &d);
}
}
if (!sel)
return 1;
prefix2sockunion(sel, addr);
return 0;
}
/* Update source selection. */
static int bgp_update_source(struct peer *peer)
{
struct interface *ifp;
union sockunion addr;
int ret = 0;
sockunion_init(&addr);
/* Source is specified with interface name. */
if (peer->update_if) {
ifp = if_lookup_by_name(peer->update_if, peer->bgp->vrf_id);
if (!ifp)
return -1;
if (bgp_update_address(ifp, &peer->su, &addr))
return -1;
ret = sockunion_bind(peer->fd, &addr, 0, &addr);
}
/* Source is specified with IP address. */
if (peer->update_source)
ret = sockunion_bind(peer->fd, peer->update_source, 0,
peer->update_source);
return ret;
}
#define DATAPLANE_MARK 254 /* main table ID */
/* BGP try to connect to the peer. */
int bgp_connect(struct peer *peer)
{
assert(!CHECK_FLAG(peer->thread_flags, PEER_THREAD_WRITES_ON));
assert(!CHECK_FLAG(peer->thread_flags, PEER_THREAD_READS_ON));
ifindex_t ifindex = 0;
if (peer->conf_if && BGP_PEER_SU_UNSPEC(peer)) {
zlog_debug("Peer address not learnt: Returning from connect");
return 0;
}
frr_elevate_privs(&bgpd_privs) {
/* Make socket for the peer. */
peer->fd = vrf_sockunion_socket(&peer->su, peer->bgp->vrf_id,
bgp_get_bound_name(peer));
}
if (peer->fd < 0)
return -1;
set_nonblocking(peer->fd);
/* Set socket send buffer size */
setsockopt_so_sendbuf(peer->fd, BGP_SOCKET_SNDBUF_SIZE);
if (bgp_set_socket_ttl(peer, peer->fd) < 0)
return -1;
sockopt_reuseaddr(peer->fd);
sockopt_reuseport(peer->fd);
if (sockopt_mark_default(peer->fd, DATAPLANE_MARK, &bgpd_privs) < 0)
flog_warn(EC_BGP_NO_SOCKOPT_MARK,
"Unable to set mark on FD for peer %s, err=%s",
peer->host, safe_strerror(errno));
#ifdef IPTOS_PREC_INTERNETCONTROL
frr_elevate_privs(&bgpd_privs) {
if (sockunion_family(&peer->su) == AF_INET)
setsockopt_ipv4_tos(peer->fd,
IPTOS_PREC_INTERNETCONTROL);
else if (sockunion_family(&peer->su) == AF_INET6)
setsockopt_ipv6_tclass(peer->fd,
IPTOS_PREC_INTERNETCONTROL);
}
#endif
if (peer->password)
bgp_md5_set_connect(peer->fd, &peer->su, peer->password);
/* Update source bind. */
if (bgp_update_source(peer) < 0) {
return connect_error;
}
if (peer->conf_if || peer->ifname)
ifindex = ifname2ifindex(peer->conf_if ? peer->conf_if
: peer->ifname,
peer->bgp->vrf_id);
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s [Event] Connect start to %s fd %d", peer->host,
peer->host, peer->fd);
/* Connect to the remote peer. */
return sockunion_connect(peer->fd, &peer->su, htons(peer->port),
ifindex);
}
/* After TCP connection is established. Get local address and port. */
int bgp_getsockname(struct peer *peer)
{
if (peer->su_local) {
sockunion_free(peer->su_local);
peer->su_local = NULL;
}
if (peer->su_remote) {
sockunion_free(peer->su_remote);
peer->su_remote = NULL;
}
peer->su_local = sockunion_getsockname(peer->fd);
if (!peer->su_local)
return -1;
peer->su_remote = sockunion_getpeername(peer->fd);
if (!peer->su_remote)
return -1;
if (!bgp_zebra_nexthop_set(peer->su_local, peer->su_remote,
&peer->nexthop, peer)) {
flog_err(EC_BGP_NH_UPD,
"%s: nexthop_set failed, resetting connection - intf %p",
peer->host, peer->nexthop.ifp);
return -1;
}
return 0;
}
static int bgp_listener(int sock, struct sockaddr *sa, socklen_t salen,
struct bgp *bgp)
{
struct bgp_listener *listener;
int ret, en;
sockopt_reuseaddr(sock);
sockopt_reuseport(sock);
frr_elevate_privs(&bgpd_privs) {
#ifdef IPTOS_PREC_INTERNETCONTROL
if (sa->sa_family == AF_INET)
setsockopt_ipv4_tos(sock, IPTOS_PREC_INTERNETCONTROL);
else if (sa->sa_family == AF_INET6)
setsockopt_ipv6_tclass(sock,
IPTOS_PREC_INTERNETCONTROL);
#endif
sockopt_v6only(sa->sa_family, sock);
ret = bind(sock, sa, salen);
en = errno;
}
if (ret < 0) {
flog_err_sys(EC_LIB_SOCKET, "bind: %s", safe_strerror(en));
return ret;
}
ret = listen(sock, SOMAXCONN);
if (ret < 0) {
flog_err_sys(EC_LIB_SOCKET, "listen: %s", safe_strerror(errno));
return ret;
}
listener = XCALLOC(MTYPE_BGP_LISTENER, sizeof(*listener));
listener->fd = sock;
/* this socket needs a change of ns. record bgp back pointer */
if (bgp->vrf_id != VRF_DEFAULT && vrf_is_backend_netns())
listener->bgp = bgp;
memcpy(&listener->su, sa, salen);
listener->thread = NULL;
thread_add_read(bm->master, bgp_accept, listener, sock,
&listener->thread);
listnode_add(bm->listen_sockets, listener);
return 0;
}
/* IPv6 supported version of BGP server socket setup. */
int bgp_socket(struct bgp *bgp, unsigned short port, const char *address)
{
struct addrinfo *ainfo;
struct addrinfo *ainfo_save;
static const struct addrinfo req = {
.ai_family = AF_UNSPEC,
.ai_flags = AI_PASSIVE,
.ai_socktype = SOCK_STREAM,
};
int ret, count;
char port_str[BUFSIZ];
snprintf(port_str, sizeof(port_str), "%d", port);
port_str[sizeof(port_str) - 1] = '\0';
frr_elevate_privs(&bgpd_privs) {
ret = vrf_getaddrinfo(address, port_str, &req, &ainfo_save,
bgp->vrf_id);
}
if (ret != 0) {
flog_err_sys(EC_LIB_SOCKET, "getaddrinfo: %s",
gai_strerror(ret));
return -1;
}
if (bgp_option_check(BGP_OPT_NO_ZEBRA) &&
bgp->vrf_id != VRF_DEFAULT) {
freeaddrinfo(ainfo_save);
return -1;
}
count = 0;
for (ainfo = ainfo_save; ainfo; ainfo = ainfo->ai_next) {
int sock;
if (ainfo->ai_family != AF_INET && ainfo->ai_family != AF_INET6)
continue;
frr_elevate_privs(&bgpd_privs) {
sock = vrf_socket(ainfo->ai_family,
ainfo->ai_socktype,
ainfo->ai_protocol, bgp->vrf_id,
(bgp->inst_type
== BGP_INSTANCE_TYPE_VRF
? bgp->name : NULL));
}
if (sock < 0) {
flog_err_sys(EC_LIB_SOCKET, "socket: %s",
safe_strerror(errno));
continue;
}
/* if we intend to implement ttl-security, this socket needs
* ttl=255 */
sockopt_ttl(ainfo->ai_family, sock, MAXTTL);
ret = bgp_listener(sock, ainfo->ai_addr, ainfo->ai_addrlen,
bgp);
if (ret == 0)
++count;
else
close(sock);
}
freeaddrinfo(ainfo_save);
if (count == 0 && bgp->inst_type != BGP_INSTANCE_TYPE_VRF) {
flog_err(
EC_LIB_SOCKET,
"%s: no usable addresses please check other programs usage of specified port %d",
__func__, port);
flog_err_sys(EC_LIB_SOCKET, "%s: Program cannot continue",
__func__);
exit(-1);
}
return 0;
}
/* this function closes vrf socket
* this should be called only for vrf socket with netns backend
*/
void bgp_close_vrf_socket(struct bgp *bgp)
{
struct listnode *node, *next;
struct bgp_listener *listener;
if (!bgp)
return;
if (bm->listen_sockets == NULL)
return;
for (ALL_LIST_ELEMENTS(bm->listen_sockets, node, next, listener)) {
if (listener->bgp == bgp) {
thread_cancel(listener->thread);
close(listener->fd);
listnode_delete(bm->listen_sockets, listener);
XFREE(MTYPE_BGP_LISTENER, listener);
}
}
}
/* this function closes main socket
*/
void bgp_close(void)
{
struct listnode *node, *next;
struct bgp_listener *listener;
if (bm->listen_sockets == NULL)
return;
for (ALL_LIST_ELEMENTS(bm->listen_sockets, node, next, listener)) {
if (listener->bgp)
continue;
thread_cancel(listener->thread);
close(listener->fd);
listnode_delete(bm->listen_sockets, listener);
XFREE(MTYPE_BGP_LISTENER, listener);
}
}
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