bfdd: don't try to start echo on protocol restart

[mirror_frr.git] / bfdd / bfd.c

/*********************************************************************
 * Copyright 2013 Cumulus Networks, LLC.  All rights reserved.
 * Copyright 2014,2015,2016,2017 Cumulus Networks, Inc.  All rights reserved.
 *
 * This program 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 of the License, or (at your option)
 * any later version.
 *
 * This program 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
 *
 * bfd.c: implements the BFD protocol.
 *
 * Authors
 * -------
 * Shrijeet Mukherjee [shm@cumulusnetworks.com]
 * Kanna Rajagopal [kanna@cumulusnetworks.com]
 * Radhika Mahankali [Radhika@cumulusnetworks.com]
 */

#include <zebra.h>

#include "lib/jhash.h"

#include "bfd.h"

DEFINE_QOBJ_TYPE(bfd_session);

/*
 * Prototypes
 */
static uint32_t ptm_bfd_gen_ID(void);
static void ptm_bfd_echo_xmt_TO(struct bfd_session *bfd);
static void bfd_session_free(struct bfd_session *bs);
static struct bfd_session *bfd_session_new(int sd);
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);


/*
 * Functions
 */
struct bfd_session *bs_peer_find(struct bfd_peer_cfg *bpc)
{
        struct bfd_session *bs;
        struct peer_label *pl;
        struct bfd_mhop_key mhop;
        struct bfd_shop_key shop;

        /* Try to find label first. */
        if (bpc->bpc_has_label) {
                pl = pl_find(bpc->bpc_label);
                if (pl != NULL) {
                        bs = pl->pl_bs;
                        return bs;
                }
        }

        /* Otherwise fallback to peer/local hash lookup. */
        if (bpc->bpc_mhop) {
                memset(&mhop, 0, sizeof(mhop));
                mhop.peer = bpc->bpc_peer;
                mhop.local = bpc->bpc_local;
                if (bpc->bpc_has_vrfname)
                        strlcpy(mhop.vrf_name, bpc->bpc_vrfname,
                                sizeof(mhop.vrf_name));

                bs = bfd_mhop_lookup(mhop);
        } else {
                memset(&shop, 0, sizeof(shop));
                shop.peer = bpc->bpc_peer;
                if (bpc->bpc_has_localif)
                        strlcpy(shop.port_name, bpc->bpc_localif,
                                sizeof(shop.port_name));

                bs = bfd_shop_lookup(shop);
        }

        return bs;
}

static uint32_t ptm_bfd_gen_ID(void)
{
        static uint32_t sessionID = 1;

        return (sessionID++);
}

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 + (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 */
        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;
        BFD_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)
                ptm_bfd_echo_xmt_TO(bfd);
}

void ptm_bfd_ses_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);

        control_notify(bfd);

        if (old_state != bfd->ses_state) {
                bfd->stats.session_up++;
                log_info("state-change: [%s] %s -> %s", bs_to_string(bfd),
                         state_list[old_state].str,
                         state_list[bfd->ses_state].str);
        }
}

void ptm_bfd_ses_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);

        ptm_bfd_snd(bfd, 0);

        /* only signal clients when going from up->down state */
        if (old_state == PTM_BFD_UP)
                control_notify(bfd);

        /* Stop echo packet transmission if they are active */
        if (BFD_CHECK_FLAG(bfd->flags, BFD_SESS_FLAG_ECHO_ACTIVE))
                ptm_bfd_echo_stop(bfd);

        if (old_state != bfd->ses_state) {
                bfd->stats.session_down++;
                log_info("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));
        }
}

static int ptm_bfd_get_vrf_name(char *port_name, char *vrf_name)
{
        struct bfd_iface *iface;
        struct bfd_vrf *vrf;

        if ((port_name == NULL) || (vrf_name == NULL))
                return -1;

        iface = bfd_iface_lookup(port_name);
        if (iface) {
                vrf = bfd_vrf_lookup(iface->vrf_id);
                if (vrf) {
                        strlcpy(vrf_name, vrf->name, sizeof(vrf->name));
                        return 0;
                }
        }
        return -1;
}

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;

        /* Remove unused fields. */
        switch (sa->sa_sin.sin_family) {
        case AF_INET:
                sa->sa_sin.sin_port = 0;
                if (memcmp(sa, &bs->shop.peer, sizeof(sa->sa_sin)) == 0)
                        return bs;
                break;
        case AF_INET6:
                sa->sa_sin6.sin6_port = 0;
                if (memcmp(sa, &bs->shop.peer, sizeof(sa->sa_sin6)) == 0)
                        return bs;
                break;
        }

        return NULL;
}

struct bfd_session *ptm_bfd_sess_find(struct bfd_pkt *cp, char *port_name,
                                      struct sockaddr_any *peer,
                                      struct sockaddr_any *local,
                                      char *vrf_name, bool is_mhop)
{
        struct bfd_session *l_bfd = NULL;
        struct bfd_mhop_key mhop;
        struct bfd_shop_key shop;
        char vrf_buf[MAXNAMELEN];

        /* 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. */
        if (is_mhop) {
                memset(&mhop, 0, sizeof(mhop));
                mhop.peer = *peer;
                mhop.local = *local;
                if (vrf_name && vrf_name[0]) {
                        strlcpy(mhop.vrf_name, vrf_name, sizeof(mhop.vrf_name));
                } else if (port_name && port_name[0]) {
                        memset(vrf_buf, 0, sizeof(vrf_buf));
                        if (ptm_bfd_get_vrf_name(port_name, vrf_buf) != -1)
                                strlcpy(mhop.vrf_name, vrf_buf,
                                        sizeof(mhop.vrf_name));
                }

                l_bfd = bfd_mhop_lookup(mhop);
        } else {
                memset(&shop, 0, sizeof(shop));
                shop.peer = *peer;
                if (port_name && port_name[0])
                        strlcpy(shop.port_name, port_name,
                                sizeof(shop.port_name));

                l_bfd = bfd_shop_lookup(shop);
        }

        /* XXX maybe remoteDiscr should be checked for remoteHeard cases. */
        return l_bfd;
}

int bfd_xmt_cb(struct thread *t)
{
        struct bfd_session *bs = THREAD_ARG(t);

        ptm_bfd_xmt_TO(bs, 0);

        return 0;
}

int bfd_echo_xmt_cb(struct thread *t)
{
        struct bfd_session *bs = THREAD_ARG(t);

        if (bs->echo_xmt_TO > 0)
                ptm_bfd_echo_xmt_TO(bs);

        return 0;
}

/* Was ptm_bfd_detect_TO() */
int bfd_recvtimer_cb(struct thread *t)
{
        struct bfd_session *bs = THREAD_ARG(t);

        switch (bs->ses_state) {
        case PTM_BFD_INIT:
        case PTM_BFD_UP:
                ptm_bfd_ses_dn(bs, BD_CONTROL_EXPIRED);
                bfd_recvtimer_update(bs);
                break;

        default:
                /* Second detect time expiration, zero remote discr (section
                 * 6.5.1)
                 */
                bs->discrs.remote_discr = 0;
                break;
        }

        return 0;
}

/* Was ptm_bfd_echo_detect_TO() */
int bfd_echo_recvtimer_cb(struct thread *t)
{
        struct bfd_session *bs = THREAD_ARG(t);

        switch (bs->ses_state) {
        case PTM_BFD_INIT:
        case PTM_BFD_UP:
                ptm_bfd_ses_dn(bs, BD_ECHO_FAILED);
                break;
        }

        return 0;
}

static struct bfd_session *bfd_session_new(int sd)
{
        struct bfd_session *bs;

        bs = XCALLOC(MTYPE_BFDD_CONFIG, sizeof(*bs));
        if (bs == NULL)
                return NULL;

        QOBJ_REG(bs, bfd_session);

        bs->timers.desired_min_tx = BFD_DEFDESIREDMINTX;
        bs->timers.required_min_rx = BFD_DEFREQUIREDMINRX;
        bs->timers.required_min_echo = BFD_DEF_REQ_MIN_ECHO;
        bs->detect_mult = BFD_DEFDETECTMULT;
        bs->mh_ttl = BFD_DEF_MHOP_TTL;

        /*
         * BFD connection startup must use slow timer.
         *
         * RFC 5880, Section 6.8.3.
         */
        bs->cur_timers.desired_min_tx = BFD_DEF_SLOWTX;
        bs->cur_timers.required_min_rx = BFD_DEF_SLOWTX;
        bs->cur_timers.required_min_echo = 0;

        /* Set the appropriated timeouts for slow connection. */
        bs->detect_TO = (BFD_DEFDETECTMULT * BFD_DEF_SLOWTX);
        bs->xmt_TO = BFD_DEF_SLOWTX;

        /* Initiate remote settings as well. */
        bs->remote_timers = bs->cur_timers;
        bs->remote_detect_mult = BFD_DEFDETECTMULT;

        bs->sock = sd;
        monotime(&bs->uptime);
        bs->downtime = bs->uptime;

        return bs;
}

int bfd_session_update_label(struct bfd_session *bs, const char *nlabel)
{
        /* New label treatment:
         * - Check if the label is taken;
         * - Try to allocate the memory for it and register;
         */
        if (bs->pl == NULL) {
                if (pl_find(nlabel) != NULL) {
                        /* Someone is already using it. */
                        return -1;
                }

                if (pl_new(nlabel, bs) == NULL)
                        return -1;

                return 0;
        }

        /*
         * Test label change consistency:
         * - Do nothing if it's the same label;
         * - Check if the future label is already taken;
         * - Change label;
         */
        if (strcmp(nlabel, bs->pl->pl_label) == 0)
                return -1;
        if (pl_find(nlabel) != NULL)
                return -1;

        strlcpy(bs->pl->pl_label, nlabel, sizeof(bs->pl->pl_label));
        return 0;
}

static void _bfd_session_update(struct bfd_session *bs,
                                struct bfd_peer_cfg *bpc)
{
        if (bpc->bpc_echo) {
                /* Check if echo mode is already active. */
                if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
                        goto skip_echo;

                BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);

                /* Activate/update echo receive timeout timer. */
                bs_echo_timer_handler(bs);
        } else {
                /* Check if echo mode is already disabled. */
                if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO))
                        goto skip_echo;

                BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_ECHO);
                ptm_bfd_echo_stop(bs);
        }

skip_echo:
        if (bpc->bpc_has_txinterval)
                bs->timers.desired_min_tx = bpc->bpc_txinterval * 1000;

        if (bpc->bpc_has_recvinterval)
                bs->timers.required_min_rx = bpc->bpc_recvinterval * 1000;

        if (bpc->bpc_has_detectmultiplier)
                bs->detect_mult = bpc->bpc_detectmultiplier;

        if (bpc->bpc_has_echointerval)
                bs->timers.required_min_echo = bpc->bpc_echointerval * 1000;

        if (bpc->bpc_has_label)
                bfd_session_update_label(bs, bpc->bpc_label);

        if (bpc->bpc_shutdown) {
                /* Check if already shutdown. */
                if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
                        return;

                BFD_SET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);

                /* Disable all events. */
                bfd_recvtimer_delete(bs);
                bfd_echo_recvtimer_delete(bs);
                bfd_xmttimer_delete(bs);
                bfd_echo_xmttimer_delete(bs);

                /* Change and notify state change. */
                bs->ses_state = PTM_BFD_ADM_DOWN;
                control_notify(bs);

                ptm_bfd_snd(bs, 0);
        } else {
                /* Check if already working. */
                if (!BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN))
                        return;

                BFD_UNSET_FLAG(bs->flags, BFD_SESS_FLAG_SHUTDOWN);

                /* Change and notify state change. */
                bs->ses_state = PTM_BFD_DOWN;
                control_notify(bs);

                /* Enable all timers. */
                bfd_recvtimer_update(bs);
                bfd_xmttimer_update(bs, bs->xmt_TO);
        }
}

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);

        control_notify_config(BCM_NOTIFY_CONFIG_UPDATE, bs);

        return 0;
}

static void bfd_session_free(struct bfd_session *bs)
{
        if (bs->sock != -1)
                close(bs->sock);

        bfd_recvtimer_delete(bs);
        bfd_echo_recvtimer_delete(bs);
        bfd_xmttimer_delete(bs);
        bfd_echo_xmttimer_delete(bs);

        bfd_id_delete(bs->discrs.my_discr);
        if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH))
                bfd_mhop_delete(bs->mhop);
        else
                bfd_shop_delete(bs->shop);

        pl_free(bs->pl);

        QOBJ_UNREG(bs);
        XFREE(MTYPE_BFDD_CONFIG, bs);
}

struct bfd_session *ptm_bfd_sess_new(struct bfd_peer_cfg *bpc)
{
        struct bfd_session *bfd, *l_bfd;
        struct interface *ifp = NULL;
        int psock;

        /* 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;
        }

        /*
         * No session found, we have to allocate a new one.
         *
         * First a few critical checks:
         *
         *   * Check that the specified interface exists.
         *   * Attempt to create the UDP socket (might fail if we exceed
         *     our limits).
         */
        if (bpc->bpc_has_localif) {
                ifp = if_lookup_by_name(bpc->bpc_localif, VRF_DEFAULT);
                if (ifp == NULL) {
                        log_error(
                                "session-new: specified interface doesn't exists.");
                        return NULL;
                }
        }

        /*
         * 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 (bpc->bpc_ipv4) {
                psock = bp_peer_socket(bpc);
                if (psock == -1)
                        return NULL;
        } else {
                psock = bp_peer_socketv6(bpc);
                if (psock == -1)
                        return NULL;
        }

        /* Get memory */
        bfd = bfd_session_new(psock);
        if (bfd == NULL) {
                log_error("session-new: allocation failed");
                return NULL;
        }

        if (bpc->bpc_has_localif && !bpc->bpc_mhop)
                bfd->ifp = ifp;

        if (bpc->bpc_ipv4 == false) {
                BFD_SET_FLAG(bfd->flags, BFD_SESS_FLAG_IPV6);

                /* Set the IPv6 scope id for link-local addresses. */
                if (IN6_IS_ADDR_LINKLOCAL(&bpc->bpc_local.sa_sin6.sin6_addr))
                        bpc->bpc_local.sa_sin6.sin6_scope_id =
                                bfd->ifp != NULL ? bfd->ifp->ifindex
                                                 : IFINDEX_INTERNAL;
                if (IN6_IS_ADDR_LINKLOCAL(&bpc->bpc_peer.sa_sin6.sin6_addr))
                        bpc->bpc_peer.sa_sin6.sin6_scope_id =
                                bfd->ifp != NULL ? bfd->ifp->ifindex
                                                 : IFINDEX_INTERNAL;
        }

        /* Initialize the session */
        bfd->ses_state = PTM_BFD_DOWN;
        bfd->discrs.my_discr = ptm_bfd_gen_ID();
        bfd->discrs.remote_discr = 0;
        bfd->local_ip = bpc->bpc_local;
        bfd->local_address = bpc->bpc_local;
        bfd_recvtimer_update(bfd);
        ptm_bfd_start_xmt_timer(bfd, false);

        /* Registrate session into data structures. */
        bfd_id_insert(bfd);

        if (bpc->bpc_mhop) {
                BFD_SET_FLAG(bfd->flags, BFD_SESS_FLAG_MH);
                bfd->mhop.peer = bpc->bpc_peer;
                bfd->mhop.local = bpc->bpc_local;
                if (bpc->bpc_has_vrfname)
                        strlcpy(bfd->mhop.vrf_name, bpc->bpc_vrfname,
                                sizeof(bfd->mhop.vrf_name));

                bfd_mhop_insert(bfd);
        } else {
                bfd->shop.peer = bpc->bpc_peer;
                if (bpc->bpc_has_localif)
                        strlcpy(bfd->shop.port_name, bpc->bpc_localif,
                                sizeof(bfd->shop.port_name));

                bfd_shop_insert(bfd);
        }

        _bfd_session_update(bfd, bpc);

        log_info("session-new: %s", bs_to_string(bfd));

        control_notify_config(BCM_NOTIFY_CONFIG_ADD, bfd);

        return bfd;
}

int ptm_bfd_ses_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) {
                log_error("session-delete: refcount failure: %" PRIu64
                          " references",
                          bs->refcount);
                return -1;
        }

        log_info("session-delete: %s", bs_to_string(bs));

        control_notify_config(BCM_NOTIFY_CONFIG_DELETE, 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.
 */
void bs_admin_down_handler(struct bfd_session *bs, int nstate);
void bs_down_handler(struct bfd_session *bs, int nstate);
void bs_init_handler(struct bfd_session *bs, int nstate);
void bs_up_handler(struct bfd_session *bs, int nstate);

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.
         */
}

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;
                break;

        case PTM_BFD_INIT:
                /*
                 * Remote peer told us his path is up, lets turn
                 * activate the session.
                 */
                ptm_bfd_ses_up(bs);
                break;

        default:
                log_debug("state-change: unhandled neighbor state: %d", nstate);
                break;
        }
}

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.
                 */
                bs->ses_state = PTM_BFD_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_ses_up(bs);
                break;

        default:
                log_debug("state-change: unhandled neighbor state: %d", nstate);
                break;
        }
}

void bs_up_handler(struct bfd_session *bs, int nstate)
{
        switch (nstate) {
        case PTM_BFD_ADM_DOWN:
        case PTM_BFD_DOWN:
                /* Peer lost or asked to shutdown connection. */
                ptm_bfd_ses_dn(bs, BD_NEIGHBOR_DOWN);
                break;

        case PTM_BFD_INIT:
        case PTM_BFD_UP:
                /* Path is up and working. */
                break;

        default:
                log_debug("state-change: unhandled neighbor state: %d", nstate);
                break;
        }
}

void bs_state_handler(struct bfd_session *bs, int nstate)
{
        switch (bs->ses_state) {
        case PTM_BFD_ADM_DOWN:
                bs_admin_down_handler(bs, nstate);
                break;
        case PTM_BFD_DOWN:
                bs_down_handler(bs, nstate);
                break;
        case PTM_BFD_INIT:
                bs_init_handler(bs, nstate);
                break;
        case PTM_BFD_UP:
                bs_up_handler(bs, nstate);
                break;

        default:
                log_debug("state-change: [%s] is in invalid state: %d",
                          bs_to_string(bs), nstate);
                break;
        }
}

/*
 * Handles echo timer manipulation after updating timer.
 */
void bs_echo_timer_handler(struct bfd_session *bs)
{
        uint32_t old_timer;

        /*
         * Before doing any echo handling, check if it is possible to
         * use it.
         *
         *   - Check for `echo-mode` configuration.
         *   - Check that we are not using multi hop (RFC 5883,
         *     Section 3).
         *   - Check that we are already at the up state.
         */
        if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO) == 0
            || BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)
            || bs->ses_state != PTM_BFD_UP)
                return;

        /* Remote peer asked to stop echo. */
        if (bs->remote_timers.required_min_echo == 0) {
                if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO_ACTIVE))
                        ptm_bfd_echo_stop(bs);

                return;
        }

        /*
         * Calculate the echo transmission timer: we must not send
         * echo packets faster than the minimum required time
         * announced by the remote system.
         *
         * RFC 5880, Section 6.8.9.
         */
        old_timer = bs->echo_xmt_TO;
        if (bs->remote_timers.required_min_echo > bs->timers.required_min_echo)
                bs->echo_xmt_TO = bs->remote_timers.required_min_echo;
        else
                bs->echo_xmt_TO = bs->timers.required_min_echo;

        if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_ECHO_ACTIVE) == 0
            || old_timer != bs->echo_xmt_TO)
                ptm_bfd_echo_start(bs);
}

/*
 * RFC 5880 Section 6.5.
 *
 * When a BFD control packet with the final bit is received, we must
 * update the session parameters.
 */
void bs_final_handler(struct bfd_session *bs)
{
        /* Start using our new timers. */
        bs->cur_timers.desired_min_tx = bs->timers.desired_min_tx;
        bs->cur_timers.required_min_rx = bs->timers.required_min_rx;

        /*
         * TODO: demand mode. See RFC 5880 Section 6.1.
         *
         * When using demand mode we must disable the detection timer
         * for lost control packets.
         */
        if (bs->demand_mode) {
                /* Notify watchers about changed timers. */
                control_notify_config(BCM_NOTIFY_CONFIG_UPDATE, bs);
                return;
        }

        /*
         * Calculate detection time based on new timers.
         *
         * Transmission calculation:
         * We must respect the RequiredMinRxInterval from the remote
         * system: if our desired transmission timer is more than the
         * minimum receive rate, then we must lower it to at least the
         * minimum receive interval.
         *
         * RFC 5880, Section 6.8.3.
         */
        if (bs->timers.desired_min_tx > bs->remote_timers.required_min_rx)
                bs->xmt_TO = bs->remote_timers.required_min_rx;
        else
                bs->xmt_TO = bs->timers.desired_min_tx;

        /* Apply new transmission timer immediately. */
        ptm_bfd_start_xmt_timer(bs, false);

        /*
         * Detection timeout calculation:
         * The minimum detection timeout is the remote detection
         * multipler (number of packets to be missed) times the agreed
         * transmission interval.
         *
         * RFC 5880, Section 6.8.4.
         *
         * TODO: support sending/counting more packets inside detection
         * timeout.
         */
        if (bs->remote_timers.required_min_rx > bs->timers.desired_min_tx)
                bs->detect_TO = bs->remote_detect_mult
                                * bs->remote_timers.required_min_rx;
        else
                bs->detect_TO = bs->remote_detect_mult
                                * bs->timers.desired_min_tx;

        /* Apply new receive timer immediately. */
        bfd_recvtimer_update(bs);

        /* Notify watchers about changed timers. */
        control_notify_config(BCM_NOTIFY_CONFIG_UPDATE, bs);
}


/*
 * Helper functions.
 */
static const char *get_diag_str(int diag)
{
        for (int i = 0; diag_list[i].str; i++) {
                if (diag_list[i].type == diag)
                        return diag_list[i].str;
        }
        return "N/A";
}

const char *satostr(struct sockaddr_any *sa)
{
#define INETSTR_BUFCOUNT 8
        static char buf[INETSTR_BUFCOUNT][INET6_ADDRSTRLEN];
        static int bufidx;
        struct sockaddr_in *sin = &sa->sa_sin;
        struct sockaddr_in6 *sin6 = &sa->sa_sin6;

        bufidx += (bufidx + 1) % INETSTR_BUFCOUNT;
        buf[bufidx][0] = 0;

        switch (sin->sin_family) {
        case AF_INET:
                inet_ntop(AF_INET, &sin->sin_addr, buf[bufidx],
                          sizeof(buf[bufidx]));
                break;
        case AF_INET6:
                inet_ntop(AF_INET6, &sin6->sin6_addr, buf[bufidx],
                          sizeof(buf[bufidx]));
                break;

        default:
                strlcpy(buf[bufidx], "unknown", sizeof(buf[bufidx]));
                break;
        }

        return buf[bufidx];
}

const char *diag2str(uint8_t diag)
{
        switch (diag) {
        case 0:
                return "ok";
        case 1:
                return "control detection time expired";
        case 2:
                return "echo function failed";
        case 3:
                return "neighbor signaled session down";
        case 4:
                return "forwarding plane reset";
        case 5:
                return "path down";
        case 6:
                return "concatenated path down";
        case 7:
                return "administratively down";
        case 8:
                return "reverse concatenated path down";
        default:
                return "unknown";
        }
}

int strtosa(const char *addr, struct sockaddr_any *sa)
{
        memset(sa, 0, sizeof(*sa));

        if (inet_pton(AF_INET, addr, &sa->sa_sin.sin_addr) == 1) {
                sa->sa_sin.sin_family = AF_INET;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
                sa->sa_sin.sin_len = sizeof(sa->sa_sin);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
                return 0;
        }

        if (inet_pton(AF_INET6, addr, &sa->sa_sin6.sin6_addr) == 1) {
                sa->sa_sin6.sin6_family = AF_INET6;
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
                sa->sa_sin6.sin6_len = sizeof(sa->sa_sin6);
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
                return 0;
        }

        return -1;
}

void integer2timestr(uint64_t time, char *buf, size_t buflen)
{
        unsigned int year, month, day, hour, minute, second;
        int rv;

#define MINUTES (60)
#define HOURS (60 * MINUTES)
#define DAYS (24 * HOURS)
#define MONTHS (30 * DAYS)
#define YEARS (12 * MONTHS)
        if (time >= YEARS) {
                year = time / YEARS;
                time -= year * YEARS;

                rv = snprintf(buf, buflen, "%u year(s), ", year);
                buf += rv;
                buflen -= rv;
        }
        if (time >= MONTHS) {
                month = time / MONTHS;
                time -= month * MONTHS;

                rv = snprintf(buf, buflen, "%u month(s), ", month);
                buf += rv;
                buflen -= rv;
        }
        if (time >= DAYS) {
                day = time / DAYS;
                time -= day * DAYS;

                rv = snprintf(buf, buflen, "%u day(s), ", day);
                buf += rv;
                buflen -= rv;
        }
        if (time >= HOURS) {
                hour = time / HOURS;
                time -= hour * HOURS;

                rv = snprintf(buf, buflen, "%u hour(s), ", hour);
                buf += rv;
                buflen -= rv;
        }
        if (time >= MINUTES) {
                minute = time / MINUTES;
                time -= minute * MINUTES;

                rv = snprintf(buf, buflen, "%u minute(s), ", minute);
                buf += rv;
                buflen -= rv;
        }
        second = time % MINUTES;
        snprintf(buf, buflen, "%u second(s)", second);
}

const char *bs_to_string(struct bfd_session *bs)
{
        static char buf[256];
        int pos;
        bool is_mhop = BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH);

        pos = snprintf(buf, sizeof(buf), "mhop:%s", is_mhop ? "yes" : "no");
        if (BFD_CHECK_FLAG(bs->flags, BFD_SESS_FLAG_MH)) {
                pos += snprintf(buf + pos, sizeof(buf) - pos,
                                " peer:%s local:%s", satostr(&bs->mhop.peer),
                                satostr(&bs->mhop.local));

                if (bs->mhop.vrf_name[0])
                        snprintf(buf + pos, sizeof(buf) - pos, " vrf:%s",
                                 bs->mhop.vrf_name);
        } else {
                pos += snprintf(buf + pos, sizeof(buf) - pos, " peer:%s",
                                satostr(&bs->shop.peer));

                if (bs->local_address.sa_sin.sin_family)
                        pos += snprintf(buf + pos, sizeof(buf) - pos,
                                        " local:%s",
                                        satostr(&bs->local_address));

                if (bs->shop.port_name[0])
                        snprintf(buf + pos, sizeof(buf) - pos, " interface:%s",
                                 bs->shop.port_name);
        }

        return buf;
}


/*
 * BFD hash data structures to find sessions.
 */
static struct hash *bfd_id_hash;
static struct hash *bfd_shop_hash;
static struct hash *bfd_mhop_hash;
static struct hash *bfd_vrf_hash;
static struct hash *bfd_iface_hash;

static unsigned int bfd_id_hash_do(void *p);
static unsigned int bfd_shop_hash_do(void *p);
static unsigned int bfd_mhop_hash_do(void *p);
static unsigned int bfd_vrf_hash_do(void *p);
static unsigned int bfd_iface_hash_do(void *p);

static void _shop_key(struct bfd_session *bs, const struct bfd_shop_key *shop);
static void _shop_key2(struct bfd_session *bs, const struct bfd_shop_key *shop);
static void _mhop_key(struct bfd_session *bs, const struct bfd_mhop_key *mhop);
static int _iface_key(struct bfd_iface *iface, const char *ifname);

static void _bfd_free(struct hash_backet *hb,
                      void *arg __attribute__((__unused__)));
static void _vrf_free(void *arg);
static void _iface_free(void *arg);

/* BFD hash for our discriminator. */
static unsigned int bfd_id_hash_do(void *p)
{
        struct bfd_session *bs = p;

        return jhash_1word(bs->discrs.my_discr, 0);
}

static bool bfd_id_hash_cmp(const void *n1, const void *n2)
{
        const struct bfd_session *bs1 = n1, *bs2 = n2;

        return bs1->discrs.my_discr == bs2->discrs.my_discr;
}

/* BFD hash for single hop. */
static unsigned int bfd_shop_hash_do(void *p)
{
        struct bfd_session *bs = p;

        return jhash(&bs->shop, sizeof(bs->shop), 0);
}

static bool bfd_shop_hash_cmp(const void *n1, const void *n2)
{
        const struct bfd_session *bs1 = n1, *bs2 = n2;

        return memcmp(&bs1->shop, &bs2->shop, sizeof(bs1->shop)) == 0;
}

/* BFD hash for multi hop. */
static unsigned int bfd_mhop_hash_do(void *p)
{
        struct bfd_session *bs = p;

        return jhash(&bs->mhop, sizeof(bs->mhop), 0);
}

static bool bfd_mhop_hash_cmp(const void *n1, const void *n2)
{
        const struct bfd_session *bs1 = n1, *bs2 = n2;

        return memcmp(&bs1->mhop, &bs2->mhop, sizeof(bs1->mhop)) == 0;
}

/* BFD hash for VRFs. */
static unsigned int bfd_vrf_hash_do(void *p)
{
        struct bfd_vrf *vrf = p;

        return jhash_1word(vrf->vrf_id, 0);
}

static bool bfd_vrf_hash_cmp(const void *n1, const void *n2)
{
        const struct bfd_vrf *v1 = n1, *v2 = n2;

        return v1->vrf_id == v2->vrf_id;
}

/* BFD hash for interfaces. */
static unsigned int bfd_iface_hash_do(void *p)
{
        struct bfd_iface *iface = p;

        return string_hash_make(iface->ifname);
}

static bool bfd_iface_hash_cmp(const void *n1, const void *n2)
{
        const struct bfd_iface *i1 = n1, *i2 = n2;

        return strcmp(i1->ifname, i2->ifname) == 0;
}

/* Helper functions */
static void _shop_key(struct bfd_session *bs, const struct bfd_shop_key *shop)
{
        bs->shop = *shop;

        /* Remove unused fields. */
        switch (bs->shop.peer.sa_sin.sin_family) {
        case AF_INET:
                bs->shop.peer.sa_sin.sin_port = 0;
                break;
        case AF_INET6:
                bs->shop.peer.sa_sin6.sin6_port = 0;
                break;
        }
}

static void _shop_key2(struct bfd_session *bs, const struct bfd_shop_key *shop)
{
        _shop_key(bs, shop);
        memset(bs->shop.port_name, 0, sizeof(bs->shop.port_name));
}

static void _mhop_key(struct bfd_session *bs, const struct bfd_mhop_key *mhop)
{
        bs->mhop = *mhop;

        /* Remove unused fields. */
        switch (bs->mhop.peer.sa_sin.sin_family) {
        case AF_INET:
                bs->mhop.peer.sa_sin.sin_port = 0;
                bs->mhop.local.sa_sin.sin_port = 0;
                break;
        case AF_INET6:
                bs->mhop.peer.sa_sin6.sin6_port = 0;
                bs->mhop.local.sa_sin6.sin6_port = 0;
                break;
        }
}

static int _iface_key(struct bfd_iface *iface, const char *ifname)
{
        size_t slen = sizeof(iface->ifname);

        memset(iface->ifname, 0, slen);
        if (strlcpy(iface->ifname, ifname, slen) >= slen)
                return -1;

        return 0;
}

/*
 * Hash public interface / exported functions.
 */

/* Lookup functions. */
struct bfd_session *bfd_id_lookup(uint32_t id)
{
        struct bfd_session bs;

        bs.discrs.my_discr = id;

        return hash_lookup(bfd_id_hash, &bs);
}

struct bfd_session *bfd_shop_lookup(struct bfd_shop_key shop)
{
        struct bfd_session bs, *bsp;

        _shop_key(&bs, &shop);

        bsp = hash_lookup(bfd_shop_hash, &bs);
        if (bsp == NULL && bs.shop.port_name[0] != 0) {
                /*
                 * Since the local interface spec is optional, try
                 * searching the key without it as well.
                 */
                _shop_key2(&bs, &shop);
                bsp = hash_lookup(bfd_shop_hash, &bs);
        }

        return bsp;
}

struct bfd_session *bfd_mhop_lookup(struct bfd_mhop_key mhop)
{
        struct bfd_session bs;

        _mhop_key(&bs, &mhop);

        return hash_lookup(bfd_mhop_hash, &bs);
}

struct bfd_vrf *bfd_vrf_lookup(int vrf_id)
{
        struct bfd_vrf vrf;

        vrf.vrf_id = vrf_id;

        return hash_lookup(bfd_vrf_hash, &vrf);
}

struct bfd_iface *bfd_iface_lookup(const char *ifname)
{
        struct bfd_iface iface;

        if (_iface_key(&iface, ifname) != 0)
                return NULL;

        return hash_lookup(bfd_iface_hash, &iface);
}

/*
 * Delete functions.
 *
 * Delete functions searches and remove the item from the hash and
 * returns a pointer to the removed item data. If the item was not found
 * then it returns NULL.
 *
 * The data stored inside the hash is not free()ed, so you must do it
 * manually after getting the pointer back.
 */
struct bfd_session *bfd_id_delete(uint32_t id)
{
        struct bfd_session bs;

        bs.discrs.my_discr = id;

        return hash_release(bfd_id_hash, &bs);
}

struct bfd_session *bfd_shop_delete(struct bfd_shop_key shop)
{
        struct bfd_session bs, *bsp;

        _shop_key(&bs, &shop);
        bsp = hash_release(bfd_shop_hash, &bs);
        if (bsp == NULL && shop.port_name[0] != 0) {
                /*
                 * Since the local interface spec is optional, try
                 * searching the key without it as well.
                 */
                _shop_key2(&bs, &shop);
                bsp = hash_release(bfd_shop_hash, &bs);
        }

        return bsp;
}

struct bfd_session *bfd_mhop_delete(struct bfd_mhop_key mhop)
{
        struct bfd_session bs;

        _mhop_key(&bs, &mhop);

        return hash_release(bfd_mhop_hash, &bs);
}

struct bfd_vrf *bfd_vrf_delete(int vrf_id)
{
        struct bfd_vrf vrf;

        vrf.vrf_id = vrf_id;

        return hash_release(bfd_vrf_hash, &vrf);
}

struct bfd_iface *bfd_iface_delete(const char *ifname)
{
        struct bfd_iface iface;

        if (_iface_key(&iface, ifname) != 0)
                return NULL;

        return hash_release(bfd_iface_hash, &iface);
}

/* Iteration functions. */
void bfd_id_iterate(hash_iter_func hif, void *arg)
{
        hash_iterate(bfd_id_hash, hif, arg);
}

void bfd_shop_iterate(hash_iter_func hif, void *arg)
{
        hash_iterate(bfd_shop_hash, hif, arg);
}

void bfd_mhop_iterate(hash_iter_func hif, void *arg)
{
        hash_iterate(bfd_mhop_hash, hif, arg);
}

void bfd_vrf_iterate(hash_iter_func hif, void *arg)
{
        hash_iterate(bfd_vrf_hash, hif, arg);
}

void bfd_iface_iterate(hash_iter_func hif, void *arg)
{
        hash_iterate(bfd_iface_hash, hif, arg);
}

/*
 * Insert functions.
 *
 * Inserts session into hash and returns `true` on success, otherwise
 * `false`.
 */
bool bfd_id_insert(struct bfd_session *bs)
{
        return (hash_get(bfd_id_hash, bs, hash_alloc_intern) == bs);
}

bool bfd_shop_insert(struct bfd_session *bs)
{
        return (hash_get(bfd_shop_hash, bs, hash_alloc_intern) == bs);
}

bool bfd_mhop_insert(struct bfd_session *bs)
{
        return (hash_get(bfd_mhop_hash, bs, hash_alloc_intern) == bs);
}

bool bfd_vrf_insert(struct bfd_vrf *vrf)
{
        return (hash_get(bfd_vrf_hash, vrf, hash_alloc_intern) == vrf);
}

bool bfd_iface_insert(struct bfd_iface *iface)
{
        return (hash_get(bfd_iface_hash, iface, hash_alloc_intern) == iface);
}

void bfd_initialize(void)
{
        bfd_id_hash = hash_create(bfd_id_hash_do, bfd_id_hash_cmp,
                                  "BFD discriminator hash");
        bfd_shop_hash = hash_create(bfd_shop_hash_do, bfd_shop_hash_cmp,
                                    "BFD single hop hash");
        bfd_mhop_hash = hash_create(bfd_mhop_hash_do, bfd_mhop_hash_cmp,
                                    "BFD multihop hop hash");
        bfd_vrf_hash =
                hash_create(bfd_vrf_hash_do, bfd_vrf_hash_cmp, "BFD VRF hash");
        bfd_iface_hash = hash_create(bfd_iface_hash_do, bfd_iface_hash_cmp,
                                     "BFD interface hash");
}

static void _bfd_free(struct hash_backet *hb,
                      void *arg __attribute__((__unused__)))
{
        struct bfd_session *bs = hb->data;

        bfd_session_free(bs);
}

static void _vrf_free(void *arg)
{
        struct bfd_vrf *vrf = arg;

        XFREE(MTYPE_BFDD_CONFIG, vrf);
}

static void _iface_free(void *arg)
{
        struct bfd_iface *iface = arg;

        XFREE(MTYPE_BFDD_CONFIG, iface);
}

void bfd_shutdown(void)
{
        /*
         * Close and free all BFD sessions.
         *
         * _bfd_free() will call bfd_session_free() which will take care
         * of removing the session from all hashes, so we just run an
         * assert() here to make sure it really happened.
         */
        bfd_id_iterate(_bfd_free, NULL);
        assert(bfd_shop_hash->count == 0);
        assert(bfd_mhop_hash->count == 0);

        /* Clean the VRF and interface hashes. */
        hash_clean(bfd_vrf_hash, _vrf_free);
        hash_clean(bfd_iface_hash, _iface_free);

        /* Now free the hashes themselves. */
        hash_free(bfd_id_hash);
        hash_free(bfd_shop_hash);
        hash_free(bfd_mhop_hash);
        hash_free(bfd_vrf_hash);
        hash_free(bfd_iface_hash);
}