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bfd.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*********************************************************************
* Copyright 2013 Cumulus Networks, LLC. All rights reserved.
* Copyright 2014,2015,2016,2017 Cumulus Networks, Inc. All rights reserved.
*
* bfd.c: implements the BFD protocol.
*
* Authors
* -------
* Shrijeet Mukherjee [[email protected]]
* Kanna Rajagopal [[email protected]]
* Radhika Mahankali [[email protected]]
*/
#include <zebra.h>
#include "lib/jhash.h"
#include "lib/network.h"
#include "bfd.h"
DEFINE_MTYPE_STATIC(BFDD, BFDD_CONFIG, "long-lived configuration memory");
DEFINE_MTYPE_STATIC(BFDD, BFDD_PROFILE, "long-lived profile memory");
DEFINE_MTYPE_STATIC(BFDD, BFDD_SESSION_OBSERVER, "Session observer");
DEFINE_MTYPE_STATIC(BFDD, BFDD_VRF, "BFD VRF");
/*
* Prototypes
*/
static uint32_t ptm_bfd_gen_ID(void);
static void ptm_bfd_echo_xmt_TO(struct bfd_session *bfd);
static struct bfd_session *bfd_find_disc(struct sockaddr_any *sa,
uint32_t ldisc);
static int bfd_session_update(struct bfd_session *bs, struct bfd_peer_cfg *bpc);
static const char *get_diag_str(int diag);
static void bs_admin_down_handler(struct bfd_session *bs, int nstate);
static void bs_down_handler(struct bfd_session *bs, int nstate);
static void bs_init_handler(struct bfd_session *bs, int nstate);
static void bs_up_handler(struct bfd_session *bs, int nstate);
/**
* Remove BFD profile from all BFD sessions so we don't leave dangling
* pointers.
*/
static void bfd_profile_detach(struct bfd_profile *bp);
/* Zeroed array with the size of an IPv6 address. */
struct in6_addr zero_addr;
/** BFD profiles list. */
struct bfdproflist bplist;
/*
* Functions
*/
struct bfd_profile *bfd_profile_lookup(const char *name)
{
struct bfd_profile *bp;
TAILQ_FOREACH (bp, &bplist, entry) {
if (strcmp(name, bp->name))
continue;
return bp;
}
return NULL;
}
static void bfd_profile_set_default(struct bfd_profile *bp)
{
bp->admin_shutdown = false;
bp->detection_multiplier = BFD_DEFDETECTMULT;
bp->echo_mode = false;
bp->passive = false;
bp->minimum_ttl = BFD_DEF_MHOP_TTL;
bp->min_echo_rx = BFD_DEF_REQ_MIN_ECHO_RX;
bp->min_echo_tx = BFD_DEF_DES_MIN_ECHO_TX;
bp->min_rx = BFD_DEFREQUIREDMINRX;
bp->min_tx = BFD_DEFDESIREDMINTX;
}
struct bfd_profile *bfd_profile_new(const char *name)
{
struct bfd_profile *bp;
/* Search for duplicates. */
if (bfd_profile_lookup(name) != NULL)
return NULL;
/* Allocate, name it and put into list. */
bp = XCALLOC(MTYPE_BFDD_PROFILE, sizeof(*bp));
strlcpy(bp->name, name, sizeof(bp->name));
TAILQ_INSERT_TAIL(&bplist, bp, entry);
/* Set default values. */
bfd_profile_set_default(bp);
return bp;
}
void bfd_profile_free(struct bfd_profile *bp)
{
/* Detach from any session. */
if (bglobal.bg_shutdown == false)
bfd_profile_detach(bp);
/* Remove from global list. */
TAILQ_REMOVE(&bplist, bp, entry);
XFREE(MTYPE_BFDD_PROFILE, bp);
}
void bfd_profile_apply(const char *profname, struct bfd_session *bs)
{
struct bfd_profile *bp;
/* Remove previous profile if any. */
if (bs->profile_name) {
/* We are changing profiles. */
if (strcmp(bs->profile_name, profname)) {
XFREE(MTYPE_BFDD_PROFILE, bs->profile_name);
bs->profile_name =
XSTRDUP(MTYPE_BFDD_PROFILE, profname);
}
} else /* Save the current profile name (in case it doesn't exist). */
bs->profile_name = XSTRDUP(MTYPE_BFDD_PROFILE, profname);
/* Look up new profile to apply. */
bp = bfd_profile_lookup(profname);
/* Point to profile if it exists. */
bs->profile = bp;
/* Apply configuration. */
bfd_session_apply(bs);
}
void bfd_session_apply(struct bfd_session *bs)
{
struct bfd_profile *bp;
uint32_t min_tx = bs->timers.desired_min_tx;
uint32_t min_rx = bs->timers.required_min_rx;
/* Pick the source of configuration. */
bp = bs->profile ? bs->profile : &bs->peer_profile;
/* Set multiplier if not the default. */
if (bs->peer_profile.detection_multiplier == BFD_DEFDETECTMULT)
bs->detect_mult = bp->detection_multiplier;
else
bs->detect_mult = bs->peer_profile.detection_multiplier;
/* Set timers if not the default. */
if (bs->peer_profile.min_tx == BFD_DEFDESIREDMINTX)
bs->timers.desired_min_tx = bp->min_tx;
else
bs->timers.desired_min_tx = bs->peer_profile.min_tx;
if (bs->peer_profile.min_rx == BFD_DEFREQUIREDMINRX)
bs->timers.required_min_rx = bp->min_rx;
else
bs->timers.required_min_rx = bs->peer_profile.min_rx;
/* We can only apply echo options on single hop sessions. */
if (!CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)) {
/* Configure echo timers if they were default. */
if (bs->peer_profile.min_echo_rx == BFD_DEF_REQ_MIN_ECHO_RX)
bs->timers.required_min_echo_rx = bp->min_echo_rx;
else
bs->timers.required_min_echo_rx =
bs->peer_profile.min_echo_rx;
if (bs->peer_profile.min_echo_tx == BFD_DEF_DES_MIN_ECHO_TX)
bs->timers.desired_min_echo_tx = bp->min_echo_tx;
else
bs->timers.desired_min_echo_tx =
bs->peer_profile.min_echo_tx;
/* Toggle echo if default value. */
if (bs->peer_profile.echo_mode == false)
bfd_set_echo(bs, bp->echo_mode);
else
bfd_set_echo(bs, bs->peer_profile.echo_mode);
} else {
/* Configure the TTL packet filter. */
if (bs->peer_profile.minimum_ttl == BFD_DEF_MHOP_TTL)
bs->mh_ttl = bp->minimum_ttl;
else
bs->mh_ttl = bs->peer_profile.minimum_ttl;
}
/* Toggle 'passive-mode' if default value. */
if (bs->peer_profile.passive == false)
bfd_set_passive_mode(bs, bp->passive);
else
bfd_set_passive_mode(bs, bs->peer_profile.passive);
/* Toggle 'no shutdown' if default value. */
if (bs->peer_profile.admin_shutdown == false)
bfd_set_shutdown(bs, bp->admin_shutdown);
else
bfd_set_shutdown(bs, bs->peer_profile.admin_shutdown);
/* If session interval changed negotiate new timers. */
if (bs->ses_state == PTM_BFD_UP
&& (bs->timers.desired_min_tx != min_tx
|| bs->timers.required_min_rx != min_rx))
bfd_set_polling(bs);
/* Send updated information to data plane. */
bfd_dplane_update_session(bs);
}
void bfd_profile_remove(struct bfd_session *bs)
{
/* Remove any previous set profile name. */
XFREE(MTYPE_BFDD_PROFILE, bs->profile_name);
bs->profile = NULL;
bfd_session_apply(bs);
}
void gen_bfd_key(struct bfd_key *key, struct sockaddr_any *peer,
struct sockaddr_any *local, bool mhop, const char *ifname,
const char *vrfname)
{
memset(key, 0, sizeof(*key));
switch (peer->sa_sin.sin_family) {
case AF_INET:
key->family = AF_INET;
memcpy(&key->peer, &peer->sa_sin.sin_addr,
sizeof(peer->sa_sin.sin_addr));
memcpy(&key->local, &local->sa_sin.sin_addr,
sizeof(local->sa_sin.sin_addr));
break;
case AF_INET6:
key->family = AF_INET6;
memcpy(&key->peer, &peer->sa_sin6.sin6_addr,
sizeof(peer->sa_sin6.sin6_addr));
memcpy(&key->local, &local->sa_sin6.sin6_addr,
sizeof(local->sa_sin6.sin6_addr));
break;
}
key->mhop = mhop;
if (ifname && ifname[0])
strlcpy(key->ifname, ifname, sizeof(key->ifname));
if (vrfname && vrfname[0])
strlcpy(key->vrfname, vrfname, sizeof(key->vrfname));
else
strlcpy(key->vrfname, VRF_DEFAULT_NAME, sizeof(key->vrfname));
}
struct bfd_session *bs_peer_find(struct bfd_peer_cfg *bpc)
{
struct bfd_key key;
/* Otherwise fallback to peer/local hash lookup. */
gen_bfd_key(&key, &bpc->bpc_peer, &bpc->bpc_local, bpc->bpc_mhop,
bpc->bpc_localif, bpc->bpc_vrfname);
return bfd_key_lookup(key);
}
/*
* Starts a disabled BFD session.
*
* A session is disabled when the specified interface/VRF doesn't exist
* yet. It might happen on FRR boot or with virtual interfaces.
*/
int bfd_session_enable(struct bfd_session *bs)
{
struct interface *ifp = NULL;
struct vrf *vrf = NULL;
int psock;
/* We are using data plane, we don't need software. */
if (bs->bdc)
return 0;
/*
* If the interface or VRF doesn't exist, then we must register
* the session but delay its start.
*/
if (bs->key.vrfname[0]) {
vrf = vrf_lookup_by_name(bs->key.vrfname);
if (vrf == NULL) {
zlog_err(
"session-enable: specified VRF %s doesn't exists.",
bs->key.vrfname);
return 0;
}
} else {
vrf = vrf_lookup_by_id(VRF_DEFAULT);
}
assert(vrf);
if (bs->key.ifname[0]) {
ifp = if_lookup_by_name(bs->key.ifname, vrf->vrf_id);
if (ifp == NULL) {
zlog_err(
"session-enable: specified interface %s (VRF %s) doesn't exist.",
bs->key.ifname, vrf->name);
return 0;
}
}
/* Assign interface/VRF pointers. */
bs->vrf = vrf;
/* Assign interface pointer (if any). */
bs->ifp = ifp;
/* Attempt to use data plane. */
if (bglobal.bg_use_dplane && bfd_dplane_add_session(bs) == 0)
return 0;
/* Sanity check: don't leak open sockets. */
if (bs->sock != -1) {
if (bglobal.debug_peer_event)
zlog_debug("%s: previous socket open", __func__);
close(bs->sock);
bs->sock = -1;
}
/*
* Get socket for transmitting control packets. Note that if we
* could use the destination port (3784) for the source
* port we wouldn't need a socket per session.
*/
if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_IPV6) == 0) {
psock = bp_peer_socket(bs);
if (psock == -1)
return 0;
} else {
psock = bp_peer_socketv6(bs);
if (psock == -1)
return 0;
}
/*
* We've got a valid socket, lets start the timers and the
* protocol.
*/
bs->sock = psock;
/* Only start timers if we are using active mode. */
if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_PASSIVE) == 0) {
bfd_recvtimer_update(bs);
ptm_bfd_start_xmt_timer(bs, false);
}
/* initialize RTT */
bfd_rtt_init(bs);
return 0;
}
/*
* Disabled a running BFD session.
*
* A session is disabled when the specified interface/VRF gets removed
* (e.g. virtual interfaces).
*/
void bfd_session_disable(struct bfd_session *bs)
{
/* We are using data plane, we don't need software. */
if (bs->bdc)
return;
/* Free up socket resources. */
if (bs->sock != -1) {
close(bs->sock);
bs->sock = -1;
}
/* Disable all timers. */
bfd_recvtimer_delete(bs);
bfd_xmttimer_delete(bs);
ptm_bfd_echo_stop(bs);
/* Set session down so it doesn't report UP and disabled. */
ptm_bfd_sess_dn(bs, BD_PATH_DOWN);
}
static uint32_t ptm_bfd_gen_ID(void)
{
uint32_t session_id;
/*
* RFC 5880, Section 6.8.1. recommends that we should generate
* random session identification numbers.
*/
do {
session_id = CHECK_FLAG((frr_weak_random() << 16), 0xFFFF0000) |
CHECK_FLAG(frr_weak_random(), 0x0000FFFF);
} while (session_id == 0 || bfd_id_lookup(session_id) != NULL);
return session_id;
}
void ptm_bfd_start_xmt_timer(struct bfd_session *bfd, bool is_echo)
{
uint64_t jitter, xmt_TO;
int maxpercent;
xmt_TO = is_echo ? bfd->echo_xmt_TO : bfd->xmt_TO;
/*
* From section 6.5.2: trasmit interval should be randomly jittered
* between
* 75% and 100% of nominal value, unless detect_mult is 1, then should
* be
* between 75% and 90%.
*/
maxpercent = (bfd->detect_mult == 1) ? 16 : 26;
jitter = (xmt_TO * (75 + (frr_weak_random() % maxpercent))) / 100;
/* XXX remove that division above */
if (is_echo)
bfd_echo_xmttimer_update(bfd, jitter);
else
bfd_xmttimer_update(bfd, jitter);
}
static void ptm_bfd_echo_xmt_TO(struct bfd_session *bfd)
{
/* Send the scheduled echo packet */
/* if ipv4 use the new echo implementation that causes
* the packet to be looped in forwarding plane of peer
*/
if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_IPV6) == 0)
#ifdef BFD_LINUX
ptm_bfd_echo_fp_snd(bfd);
#else
ptm_bfd_echo_snd(bfd);
#endif
else
ptm_bfd_echo_snd(bfd);
/* Restart the timer for next time */
ptm_bfd_start_xmt_timer(bfd, true);
}
void ptm_bfd_xmt_TO(struct bfd_session *bfd, int fbit)
{
/* Send the scheduled control packet */
ptm_bfd_snd(bfd, fbit);
/* Restart the timer for next time */
ptm_bfd_start_xmt_timer(bfd, false);
}
void ptm_bfd_echo_stop(struct bfd_session *bfd)
{
bfd->echo_xmt_TO = 0;
bfd->echo_detect_TO = 0;
UNSET_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE);
bfd_echo_xmttimer_delete(bfd);
bfd_echo_recvtimer_delete(bfd);
}
void ptm_bfd_echo_start(struct bfd_session *bfd)
{
bfd->echo_detect_TO = (bfd->remote_detect_mult * bfd->echo_xmt_TO);
if (bfd->echo_detect_TO > 0) {
bfd_echo_recvtimer_update(bfd);
ptm_bfd_echo_xmt_TO(bfd);
}
}
void ptm_bfd_sess_up(struct bfd_session *bfd)
{
int old_state = bfd->ses_state;
bfd->local_diag = 0;
bfd->ses_state = PTM_BFD_UP;
monotime(&bfd->uptime);
/* Connection is up, lets negotiate timers. */
bfd_set_polling(bfd);
/* Start sending control packets with poll bit immediately. */
ptm_bfd_snd(bfd, 0);
ptm_bfd_notify(bfd, bfd->ses_state);
if (old_state != bfd->ses_state) {
bfd->stats.session_up++;
if (bglobal.debug_peer_event)
zlog_debug("state-change: [%s] %s -> %s",
bs_to_string(bfd), state_list[old_state].str,
state_list[bfd->ses_state].str);
}
}
void ptm_bfd_sess_dn(struct bfd_session *bfd, uint8_t diag)
{
int old_state = bfd->ses_state;
bfd->local_diag = diag;
bfd->discrs.remote_discr = 0;
bfd->ses_state = PTM_BFD_DOWN;
bfd->polling = 0;
bfd->demand_mode = 0;
monotime(&bfd->downtime);
/*
* Only attempt to send if we have a valid socket:
* this function might be called by session disablers and in
* this case we won't have a valid socket (i.e. interface was
* removed or VRF doesn't exist anymore).
*/
if (bfd->sock != -1)
ptm_bfd_snd(bfd, 0);
/* Slow down the control packets, the connection is down. */
bs_set_slow_timers(bfd);
/* only signal clients when going from up->down state */
if (old_state == PTM_BFD_UP)
ptm_bfd_notify(bfd, PTM_BFD_DOWN);
/* Stop echo packet transmission if they are active */
if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE))
ptm_bfd_echo_stop(bfd);
/* Stop attempting to transmit or expect control packets if passive. */
if (CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_PASSIVE)) {
bfd_recvtimer_delete(bfd);
bfd_xmttimer_delete(bfd);
}
if (old_state != bfd->ses_state) {
bfd->stats.session_down++;
if (bglobal.debug_peer_event)
zlog_debug("state-change: [%s] %s -> %s reason:%s",
bs_to_string(bfd), state_list[old_state].str,
state_list[bfd->ses_state].str,
get_diag_str(bfd->local_diag));
}
/* clear peer's mac address */
UNSET_FLAG(bfd->flags, BFD_SESS_FLAG_MAC_SET);
memset(bfd->peer_hw_addr, 0, sizeof(bfd->peer_hw_addr));
/* reset local address ,it might has been be changed after bfd is up*/
memset(&bfd->local_address, 0, sizeof(bfd->local_address));
/* reset RTT */
bfd_rtt_init(bfd);
}
static struct bfd_session *bfd_find_disc(struct sockaddr_any *sa,
uint32_t ldisc)
{
struct bfd_session *bs;
bs = bfd_id_lookup(ldisc);
if (bs == NULL)
return NULL;
switch (bs->key.family) {
case AF_INET:
if (memcmp(&sa->sa_sin.sin_addr, &bs->key.peer,
sizeof(sa->sa_sin.sin_addr)))
return NULL;
break;
case AF_INET6:
if (memcmp(&sa->sa_sin6.sin6_addr, &bs->key.peer,
sizeof(sa->sa_sin6.sin6_addr)))
return NULL;
break;
}
return bs;
}
struct bfd_session *ptm_bfd_sess_find(struct bfd_pkt *cp,
struct sockaddr_any *peer,
struct sockaddr_any *local,
struct interface *ifp,
vrf_id_t vrfid,
bool is_mhop)
{
struct vrf *vrf;
struct bfd_key key;
/* Find our session using the ID signaled by the remote end. */
if (cp->discrs.remote_discr)
return bfd_find_disc(peer, ntohl(cp->discrs.remote_discr));
/* Search for session without using discriminator. */
vrf = vrf_lookup_by_id(vrfid);
gen_bfd_key(&key, peer, local, is_mhop, ifp ? ifp->name : NULL,
vrf ? vrf->name : VRF_DEFAULT_NAME);
/* XXX maybe remoteDiscr should be checked for remoteHeard cases. */
return bfd_key_lookup(key);
}
void bfd_xmt_cb(struct event *t)
{
struct bfd_session *bs = EVENT_ARG(t);
ptm_bfd_xmt_TO(bs, 0);
}
void bfd_echo_xmt_cb(struct event *t)
{
struct bfd_session *bs = EVENT_ARG(t);
if (bs->echo_xmt_TO > 0)
ptm_bfd_echo_xmt_TO(bs);
}
/* Was ptm_bfd_detect_TO() */
void bfd_recvtimer_cb(struct event *t)
{
struct bfd_session *bs = EVENT_ARG(t);
switch (bs->ses_state) {
case PTM_BFD_INIT:
case PTM_BFD_UP:
ptm_bfd_sess_dn(bs, BD_CONTROL_EXPIRED);
break;
}
}
/* Was ptm_bfd_echo_detect_TO() */
void bfd_echo_recvtimer_cb(struct event *t)
{
struct bfd_session *bs = EVENT_ARG(t);
switch (bs->ses_state) {
case PTM_BFD_INIT:
case PTM_BFD_UP:
ptm_bfd_sess_dn(bs, BD_ECHO_FAILED);
break;
}
}
struct bfd_session *bfd_session_new(void)
{
struct bfd_session *bs;
bs = XCALLOC(MTYPE_BFDD_CONFIG, sizeof(*bs));
/* Set peer session defaults. */
bfd_profile_set_default(&bs->peer_profile);
bs->timers.desired_min_tx = BFD_DEFDESIREDMINTX;
bs->timers.required_min_rx = BFD_DEFREQUIREDMINRX;
bs->timers.required_min_echo_rx = BFD_DEF_REQ_MIN_ECHO_RX;
bs->timers.desired_min_echo_tx = BFD_DEF_DES_MIN_ECHO_TX;
bs->detect_mult = BFD_DEFDETECTMULT;
bs->mh_ttl = BFD_DEF_MHOP_TTL;
bs->ses_state = PTM_BFD_DOWN;
/* Initiate connection with slow timers. */
bs_set_slow_timers(bs);
/* Initiate remote settings as well. */
bs->remote_timers = bs->cur_timers;
bs->remote_detect_mult = BFD_DEFDETECTMULT;
bs->sock = -1;
monotime(&bs->uptime);
bs->downtime = bs->uptime;
return bs;
}
static void _bfd_session_update(struct bfd_session *bs,
struct bfd_peer_cfg *bpc)
{
if (bpc->bpc_has_txinterval) {
bs->timers.desired_min_tx = bpc->bpc_txinterval * 1000;
bs->peer_profile.min_tx = bs->timers.desired_min_tx;
}
if (bpc->bpc_has_recvinterval) {
bs->timers.required_min_rx = bpc->bpc_recvinterval * 1000;
bs->peer_profile.min_rx = bs->timers.required_min_rx;
}
if (bpc->bpc_has_detectmultiplier) {
bs->detect_mult = bpc->bpc_detectmultiplier;
bs->peer_profile.detection_multiplier = bs->detect_mult;
}
if (bpc->bpc_has_echorecvinterval) {
bs->timers.required_min_echo_rx = bpc->bpc_echorecvinterval * 1000;
bs->peer_profile.min_echo_rx = bs->timers.required_min_echo_rx;
}
if (bpc->bpc_has_echotxinterval) {
bs->timers.desired_min_echo_tx = bpc->bpc_echotxinterval * 1000;
bs->peer_profile.min_echo_tx = bs->timers.desired_min_echo_tx;
}
if (bpc->bpc_cbit)
SET_FLAG(bs->flags, BFD_SESS_FLAG_CBIT);
else
UNSET_FLAG(bs->flags, BFD_SESS_FLAG_CBIT);
if (bpc->bpc_has_minimum_ttl) {
bs->mh_ttl = bpc->bpc_minimum_ttl;
bs->peer_profile.minimum_ttl = bpc->bpc_minimum_ttl;
}
bs->peer_profile.echo_mode = bpc->bpc_echo;
bfd_set_echo(bs, bpc->bpc_echo);
/*
* Shutdown needs to be the last in order to avoid timers enable when
* the session is disabled.
*/
bs->peer_profile.admin_shutdown = bpc->bpc_shutdown;
bfd_set_passive_mode(bs, bpc->bpc_passive);
bfd_set_shutdown(bs, bpc->bpc_shutdown);
/*
* Apply profile last: it also calls `bfd_set_shutdown`.
*
* There is no problem calling `shutdown` twice if the value doesn't
* change or if it is overridden by peer specific configuration.
*/
if (bpc->bpc_has_profile)
bfd_profile_apply(bpc->bpc_profile, bs);
}
static int bfd_session_update(struct bfd_session *bs, struct bfd_peer_cfg *bpc)
{
/* User didn't want to update, return failure. */
if (bpc->bpc_createonly)
return -1;
_bfd_session_update(bs, bpc);
return 0;
}
void bfd_session_free(struct bfd_session *bs)
{
struct bfd_session_observer *bso;
bfd_session_disable(bs);
/* Remove session from data plane if any. */
bfd_dplane_delete_session(bs);
bfd_key_delete(bs->key);
bfd_id_delete(bs->discrs.my_discr);
/* Remove observer if any. */
TAILQ_FOREACH(bso, &bglobal.bg_obslist, bso_entry) {
if (bso->bso_bs != bs)
continue;
break;
}
if (bso != NULL)
bs_observer_del(bso);
XFREE(MTYPE_BFDD_PROFILE, bs->profile_name);
XFREE(MTYPE_BFDD_CONFIG, bs);
}
struct bfd_session *ptm_bfd_sess_new(struct bfd_peer_cfg *bpc)
{
struct bfd_session *bfd, *l_bfd;
/* check to see if this needs a new session */
l_bfd = bs_peer_find(bpc);
if (l_bfd) {
/* Requesting a duplicated peer means update configuration. */
if (bfd_session_update(l_bfd, bpc) == 0)
return l_bfd;
else
return NULL;
}
/* Get BFD session storage with its defaults. */
bfd = bfd_session_new();
/*
* Store interface/VRF name in case we need to delay session
* start. See `bfd_session_enable` for more information.
*/
if (bpc->bpc_has_localif)
strlcpy(bfd->key.ifname, bpc->bpc_localif,
sizeof(bfd->key.ifname));
if (bpc->bpc_has_vrfname)
strlcpy(bfd->key.vrfname, bpc->bpc_vrfname,
sizeof(bfd->key.vrfname));
else
strlcpy(bfd->key.vrfname, VRF_DEFAULT_NAME,
sizeof(bfd->key.vrfname));
/* Copy remaining data. */
if (bpc->bpc_ipv4 == false)
SET_FLAG(bfd->flags, BFD_SESS_FLAG_IPV6);
bfd->key.family = (bpc->bpc_ipv4) ? AF_INET : AF_INET6;
switch (bfd->key.family) {
case AF_INET:
memcpy(&bfd->key.peer, &bpc->bpc_peer.sa_sin.sin_addr,
sizeof(bpc->bpc_peer.sa_sin.sin_addr));
memcpy(&bfd->key.local, &bpc->bpc_local.sa_sin.sin_addr,
sizeof(bpc->bpc_local.sa_sin.sin_addr));
break;
case AF_INET6:
memcpy(&bfd->key.peer, &bpc->bpc_peer.sa_sin6.sin6_addr,
sizeof(bpc->bpc_peer.sa_sin6.sin6_addr));
memcpy(&bfd->key.local, &bpc->bpc_local.sa_sin6.sin6_addr,
sizeof(bpc->bpc_local.sa_sin6.sin6_addr));
break;
default:
assert(1);
break;
}
if (bpc->bpc_mhop)
SET_FLAG(bfd->flags, BFD_SESS_FLAG_MH);
bfd->key.mhop = bpc->bpc_mhop;
if (bs_registrate(bfd) == NULL)
return NULL;
/* Apply other configurations. */
_bfd_session_update(bfd, bpc);
return bfd;
}
struct bfd_session *bs_registrate(struct bfd_session *bfd)
{
/* Registrate session into data structures. */
bfd_key_insert(bfd);
bfd->discrs.my_discr = ptm_bfd_gen_ID();
bfd_id_insert(bfd);
/* Try to enable session and schedule for packet receive/send. */
if (bfd_session_enable(bfd) == -1) {
/* Unrecoverable failure, remove the session/peer. */
bfd_session_free(bfd);
return NULL;
}
/* Add observer if we have moving parts. */
if (bfd->key.ifname[0] || bfd->key.vrfname[0] || bfd->sock == -1)
bs_observer_add(bfd);
if (bglobal.debug_peer_event)
zlog_debug("session-new: %s", bs_to_string(bfd));
return bfd;
}
int ptm_bfd_sess_del(struct bfd_peer_cfg *bpc)
{
struct bfd_session *bs;
/* Find session and call free(). */
bs = bs_peer_find(bpc);
if (bs == NULL)
return -1;
/* This pointer is being referenced, don't let it be deleted. */
if (bs->refcount > 0) {
zlog_err("session-delete: refcount failure: %" PRIu64" references",
bs->refcount);
return -1;
}
if (bglobal.debug_peer_event)
zlog_debug("%s: %s", __func__, bs_to_string(bs));
bfd_session_free(bs);
return 0;
}
void bfd_set_polling(struct bfd_session *bs)
{
/*
* Start polling procedure: the only timers that require polling
* to change value without losing connection are:
*
* - Desired minimum transmission interval;
* - Required minimum receive interval;
*
* RFC 5880, Section 6.8.3.
*/
bs->polling = 1;
}
/*
* bs_<state>_handler() functions implement the BFD state machine
* transition mechanism. `<state>` is the current session state and
* the parameter `nstate` is the peer new state.
*/
static void bs_admin_down_handler(struct bfd_session *bs
__attribute__((__unused__)),
int nstate __attribute__((__unused__)))
{
/*
* We are administratively down, there is no state machine
* handling.
*/
}
static void bs_down_handler(struct bfd_session *bs, int nstate)
{
switch (nstate) {
case PTM_BFD_ADM_DOWN:
/*
* Remote peer doesn't want to talk, so lets keep the
* connection down.
*/
case PTM_BFD_UP:
/* Peer can't be up yet, wait it go to 'init' or 'down'. */
break;
case PTM_BFD_DOWN:
/*
* Remote peer agreed that the path is down, lets try to
* bring it up.
*/
bs->ses_state = PTM_BFD_INIT;
/*
* RFC 5880, Section 6.1.
* A system taking the Passive role MUST NOT begin
* sending BFD packets for a particular session until
* it has received a BFD packet for that session, and thus
* has learned the remote system's discriminator value.
*
* Now we can start transmission timer in passive mode.
*/
if (CHECK_FLAG(bs->flags, BFD_SESS_FLAG_PASSIVE))
ptm_bfd_xmt_TO(bs, 0);
break;
case PTM_BFD_INIT:
/*
* Remote peer told us his path is up, lets turn
* activate the session.
*/
ptm_bfd_sess_up(bs);
break;
default:
if (bglobal.debug_peer_event)
zlog_debug("state-change: unhandled neighbor state: %d",
nstate);
break;
}
}
static void bs_init_handler(struct bfd_session *bs, int nstate)
{
switch (nstate) {
case PTM_BFD_ADM_DOWN:
/*
* Remote peer doesn't want to talk, so lets make the
* connection down.
*/
ptm_bfd_sess_dn(bs, BD_NEIGHBOR_DOWN);
break;
case PTM_BFD_DOWN:
/* Remote peer hasn't moved to first stage yet. */
break;
case PTM_BFD_INIT:
case PTM_BFD_UP:
/* We agreed on the settings and the path is up. */
ptm_bfd_sess_up(bs);
break;
default:
if (bglobal.debug_peer_event)
zlog_debug("state-change: unhandled neighbor state: %d",
nstate);
break;
}
}