* Copyright (c) 2000 Jason L. Wright (jason@thought.net)

/* $NetBSD: bridgestp.c,v 1.27 2024/07/05 04:31:53 rin Exp $ */

/*
* Copyright (c) 2000 Jason L. Wright ([email protected])
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Jason L. Wright
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* OpenBSD: bridgestp.c,v 1.5 2001/03/22 03:48:29 jason Exp
*/

/*
* Implementation of the spanning tree protocol as defined in
* ISO/IEC Final DIS 15802-3 (IEEE P802.1D/D17), May 25, 1998.
* (In English: IEEE 802.1D, Draft 17, 1998)
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: bridgestp.c,v 1.27 2024/07/05 04:31:53 rin Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/callout.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/if_llc.h>

#include <net/if_ether.h>
#include <net/if_bridgevar.h>

/* BPDU message types */
#define BSTP_MSGTYPE_CFG 0x00 /* Configuration */
#define BSTP_MSGTYPE_TCN 0x80 /* Topology chg notification */

/* BPDU flags */
#define BSTP_FLAG_TC 0x01 /* Topology change */
#define BSTP_FLAG_TCA 0x80 /* Topology change ack */

#define BSTP_MESSAGE_AGE_INCR (1 * 256) /* in 256ths of a second */
#define BSTP_TICK_VAL (1 * 256) /* in 256ths of a second */

/*
* Because BPDU's do not make nicely aligned structures, two different
* declarations are used: bstp_?bpdu (wire representation, packed) and
* bstp_*_unit (internal, nicely aligned version).
*/

/* configuration bridge protocol data unit */
struct bstp_cbpdu {
uint8_t cbu_dsap; /* LLC: destination sap */
uint8_t cbu_ssap; /* LLC: source sap */
uint8_t cbu_ctl; /* LLC: control */
uint16_t cbu_protoid; /* protocol id */
uint8_t cbu_protover; /* protocol version */
uint8_t cbu_bpdutype; /* message type */
uint8_t cbu_flags; /* flags (below) */

/* root id */
uint16_t cbu_rootpri; /* root priority */
uint8_t cbu_rootaddr[6]; /* root address */

uint32_t cbu_rootpathcost; /* root path cost */

/* bridge id */
uint16_t cbu_bridgepri; /* bridge priority */
uint8_t cbu_bridgeaddr[6]; /* bridge address */

uint16_t cbu_portid; /* port id */
uint16_t cbu_messageage; /* current message age */
uint16_t cbu_maxage; /* maximum age */
uint16_t cbu_hellotime; /* hello time */
uint16_t cbu_forwarddelay; /* forwarding delay */
} __packed;

/* topology change notification bridge protocol data unit */
struct bstp_tbpdu {
uint8_t tbu_dsap; /* LLC: destination sap */
uint8_t tbu_ssap; /* LLC: source sap */
uint8_t tbu_ctl; /* LLC: control */
uint16_t tbu_protoid; /* protocol id */
uint8_t tbu_protover; /* protocol version */
uint8_t tbu_bpdutype; /* message type */
} __packed;

const uint8_t bstp_etheraddr[] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };

static void bstp_initialize_port(struct bridge_softc *, struct bridge_iflist *);
static void bstp_ifupdstatus(struct bridge_softc *, struct bridge_iflist *);
static void bstp_enable_port(struct bridge_softc *, struct bridge_iflist *);
static void bstp_disable_port(struct bridge_softc *, struct bridge_iflist *);
static int bstp_root_bridge(struct bridge_softc *sc);
static int bstp_supersedes_port_info(struct bridge_softc *,
struct bridge_iflist *,
struct bstp_config_unit *);
static int bstp_designated_port(struct bridge_softc *, struct bridge_iflist *);
static int bstp_designated_for_some_port(struct bridge_softc *);
static void bstp_transmit_config(struct bridge_softc *, struct bridge_iflist *);
static void bstp_transmit_tcn(struct bridge_softc *);
static void bstp_received_config_bpdu(struct bridge_softc *,
struct bridge_iflist *,
struct bstp_config_unit *);
static void bstp_received_tcn_bpdu(struct bridge_softc *, struct bridge_iflist *,
struct bstp_tcn_unit *);
static void bstp_record_config_information(struct bridge_softc *,
struct bridge_iflist *,
struct bstp_config_unit *);
static void bstp_record_config_timeout_values(struct bridge_softc *,
struct bstp_config_unit *);
static void bstp_config_bpdu_generation(struct bridge_softc *);
static void bstp_send_config_bpdu(struct bridge_softc *, struct bridge_iflist *,
struct bstp_config_unit *);
static void bstp_configuration_update(struct bridge_softc *);
static void bstp_root_selection(struct bridge_softc *);
static void bstp_designated_port_selection(struct bridge_softc *);
static void bstp_become_designated_port(struct bridge_softc *,
struct bridge_iflist *);
static void bstp_port_state_selection(struct bridge_softc *);
static void bstp_make_forwarding(struct bridge_softc *, struct bridge_iflist *);
static void bstp_make_blocking(struct bridge_softc *, struct bridge_iflist *);
static void bstp_set_port_state(struct bridge_iflist *, uint8_t);
#if notused
static void bstp_set_bridge_priority(struct bridge_softc *, uint64_t);
static void bstp_set_port_priority(struct bridge_softc *, struct bridge_iflist *,
uint16_t);
static void bstp_set_path_cost(struct bridge_softc *, struct bridge_iflist *,
uint32_t);
#endif
static void bstp_topology_change_detection(struct bridge_softc *);
static void bstp_topology_change_acknowledged(struct bridge_softc *);
static void bstp_acknowledge_topology_change(struct bridge_softc *,
struct bridge_iflist *);

static void bstp_tick(void *);
static void bstp_timer_start(struct bridge_timer *, uint16_t);
static void bstp_timer_stop(struct bridge_timer *);
static int bstp_timer_expired(struct bridge_timer *, uint16_t);

static void bstp_hold_timer_expiry(struct bridge_softc *, struct bridge_iflist *);
static void bstp_message_age_timer_expiry(struct bridge_softc *,
struct bridge_iflist *);
static void bstp_forward_delay_timer_expiry(struct bridge_softc *,
struct bridge_iflist *);
static void bstp_topology_change_timer_expiry(struct bridge_softc *);
static void bstp_tcn_timer_expiry(struct bridge_softc *);
static void bstp_hello_timer_expiry(struct bridge_softc *);

static void
bstp_transmit_config(struct bridge_softc *sc, struct bridge_iflist *bif)
{
if (bif->bif_hold_timer.active) {
bif->bif_config_pending = 1;
return;
}

bif->bif_config_bpdu.cu_message_type = BSTP_MSGTYPE_CFG;
bif->bif_config_bpdu.cu_rootid = sc->sc_designated_root;
bif->bif_config_bpdu.cu_root_path_cost = sc->sc_root_path_cost;
bif->bif_config_bpdu.cu_bridge_id = sc->sc_bridge_id;
bif->bif_config_bpdu.cu_port_id = bif->bif_port_id;

if (bstp_root_bridge(sc))
bif->bif_config_bpdu.cu_message_age = 0;
else
bif->bif_config_bpdu.cu_message_age =
sc->sc_root_port->bif_message_age_timer.value +
BSTP_MESSAGE_AGE_INCR;

bif->bif_config_bpdu.cu_max_age = sc->sc_max_age;
bif->bif_config_bpdu.cu_hello_time = sc->sc_hello_time;
bif->bif_config_bpdu.cu_forward_delay = sc->sc_forward_delay;
bif->bif_config_bpdu.cu_topology_change_acknowledgment
= bif->bif_topology_change_acknowledge;
bif->bif_config_bpdu.cu_topology_change = sc->sc_topology_change;

if (bif->bif_config_bpdu.cu_message_age < sc->sc_max_age) {
bif->bif_topology_change_acknowledge = 0;
bif->bif_config_pending = 0;
bstp_send_config_bpdu(sc, bif, &bif->bif_config_bpdu);
bstp_timer_start(&bif->bif_hold_timer, 0);
}
}

static void
bstp_send_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
struct bstp_config_unit *cu)
{
struct ifnet *ifp;
struct mbuf *m;
struct ether_header *eh;
struct bstp_cbpdu bpdu;

KASSERT(BRIDGE_LOCKED(sc));

ifp = bif->bif_ifp;

if ((ifp->if_flags & IFF_RUNNING) == 0)
return;

MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL)
return;

eh = mtod(m, struct ether_header *);

m_set_rcvif(m, ifp);
m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
m->m_len = m->m_pkthdr.len;

bpdu.cbu_ssap = bpdu.cbu_dsap = LLC_8021D_LSAP;
bpdu.cbu_ctl = LLC_UI;
bpdu.cbu_protoid = htons(0);
bpdu.cbu_protover = 0;
bpdu.cbu_bpdutype = cu->cu_message_type;
bpdu.cbu_flags = (cu->cu_topology_change ? BSTP_FLAG_TC : 0) |
(cu->cu_topology_change_acknowledgment ? BSTP_FLAG_TCA : 0);

bpdu.cbu_rootpri = htons(cu->cu_rootid >> 48);
bpdu.cbu_rootaddr[0] = cu->cu_rootid >> 40;
bpdu.cbu_rootaddr[1] = cu->cu_rootid >> 32;
bpdu.cbu_rootaddr[2] = cu->cu_rootid >> 24;
bpdu.cbu_rootaddr[3] = cu->cu_rootid >> 16;
bpdu.cbu_rootaddr[4] = cu->cu_rootid >> 8;
bpdu.cbu_rootaddr[5] = cu->cu_rootid >> 0;

bpdu.cbu_rootpathcost = htonl(cu->cu_root_path_cost);

bpdu.cbu_bridgepri = htons(cu->cu_rootid >> 48);
bpdu.cbu_bridgeaddr[0] = cu->cu_rootid >> 40;
bpdu.cbu_bridgeaddr[1] = cu->cu_rootid >> 32;
bpdu.cbu_bridgeaddr[2] = cu->cu_rootid >> 24;
bpdu.cbu_bridgeaddr[3] = cu->cu_rootid >> 16;
bpdu.cbu_bridgeaddr[4] = cu->cu_rootid >> 8;
bpdu.cbu_bridgeaddr[5] = cu->cu_rootid >> 0;

bpdu.cbu_portid = htons(cu->cu_port_id);
bpdu.cbu_messageage = htons(cu->cu_message_age);
bpdu.cbu_maxage = htons(cu->cu_max_age);
bpdu.cbu_hellotime = htons(cu->cu_hello_time);
bpdu.cbu_forwarddelay = htons(cu->cu_forward_delay);

memcpy(eh->ether_shost, CLLADDR(ifp->if_sadl), ETHER_ADDR_LEN);
memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
eh->ether_type = htons(sizeof(bpdu));

memcpy(mtod(m, char *) + sizeof(*eh), &bpdu, sizeof(bpdu));

BRIDGE_UNLOCK(sc);
bridge_enqueue(sc, ifp, m, 0);
BRIDGE_LOCK(sc);
}

static int
bstp_root_bridge(struct bridge_softc *sc)
{
return (sc->sc_designated_root == sc->sc_bridge_id);
}

static int
bstp_supersedes_port_info(struct bridge_softc *sc, struct bridge_iflist *bif,
struct bstp_config_unit *cu)
{
if (cu->cu_rootid < bif->bif_designated_root)
return (1);
if (cu->cu_rootid > bif->bif_designated_root)
return (0);

if (cu->cu_root_path_cost < bif->bif_designated_cost)
return (1);
if (cu->cu_root_path_cost > bif->bif_designated_cost)
return (0);

if (cu->cu_bridge_id < bif->bif_designated_bridge)
return (1);
if (cu->cu_bridge_id > bif->bif_designated_bridge)
return (0);

if (sc->sc_bridge_id != cu->cu_bridge_id)
return (1);
if (cu->cu_port_id <= bif->bif_designated_port)
return (1);
return (0);
}

static void
bstp_record_config_information(struct bridge_softc *sc,
struct bridge_iflist *bif, struct bstp_config_unit *cu)
{
bif->bif_designated_root = cu->cu_rootid;
bif->bif_designated_cost = cu->cu_root_path_cost;
bif->bif_designated_bridge = cu->cu_bridge_id;
bif->bif_designated_port = cu->cu_port_id;
bstp_timer_start(&bif->bif_message_age_timer, cu->cu_message_age);
}

static void
bstp_record_config_timeout_values(struct bridge_softc *sc,
struct bstp_config_unit *config)
{
sc->sc_max_age = config->cu_max_age;
sc->sc_hello_time = config->cu_hello_time;
sc->sc_forward_delay = config->cu_forward_delay;
sc->sc_topology_change = config->cu_topology_change;
}

static void
bstp_config_bpdu_generation(struct bridge_softc *sc)
{
struct bridge_iflist *bif;

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_designated_port(sc, bif) &&
(bif->bif_state != BSTP_IFSTATE_DISABLED))
bstp_transmit_config(sc, bif);
}
}

static int
bstp_designated_port(struct bridge_softc *sc, struct bridge_iflist *bif)
{
return ((bif->bif_designated_bridge == sc->sc_bridge_id)
&& (bif->bif_designated_port == bif->bif_port_id));
}

static void
bstp_transmit_tcn(struct bridge_softc *sc)
{
struct bstp_tbpdu bpdu;
struct bridge_iflist *bif = sc->sc_root_port;
struct ifnet *ifp;
struct ether_header *eh;
struct mbuf *m;

KASSERT(BRIDGE_LOCKED(sc));

KASSERT(bif != NULL);
ifp = bif->bif_ifp;
if ((ifp->if_flags & IFF_RUNNING) == 0)
return;

MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL)
return;

m_set_rcvif(m, ifp);
m->m_pkthdr.len = sizeof(*eh) + sizeof(bpdu);
m->m_len = m->m_pkthdr.len;

eh = mtod(m, struct ether_header *);

memcpy(eh->ether_shost, CLLADDR(ifp->if_sadl), ETHER_ADDR_LEN);
memcpy(eh->ether_dhost, bstp_etheraddr, ETHER_ADDR_LEN);
eh->ether_type = htons(sizeof(bpdu));

bpdu.tbu_ssap = bpdu.tbu_dsap = LLC_8021D_LSAP;
bpdu.tbu_ctl = LLC_UI;
bpdu.tbu_protoid = 0;
bpdu.tbu_protover = 0;
bpdu.tbu_bpdutype = BSTP_MSGTYPE_TCN;

memcpy(mtod(m, char *) + sizeof(*eh), &bpdu, sizeof(bpdu));

BRIDGE_UNLOCK(sc);
bridge_enqueue(sc, ifp, m, 0);
BRIDGE_LOCK(sc);
}

static void
bstp_configuration_update(struct bridge_softc *sc)
{
bstp_root_selection(sc);
bstp_designated_port_selection(sc);
}

static void
bstp_root_selection(struct bridge_softc *sc)
{
struct bridge_iflist *root_port = NULL, *bif;

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_designated_port(sc, bif))
continue;
if (bif->bif_state == BSTP_IFSTATE_DISABLED)
continue;
if (bif->bif_designated_root >= sc->sc_bridge_id)
continue;
if (root_port == NULL)
goto set_port;

if (bif->bif_designated_root < root_port->bif_designated_root)
goto set_port;
if (bif->bif_designated_root > root_port->bif_designated_root)
continue;

if ((bif->bif_designated_cost + bif->bif_path_cost) <
(root_port->bif_designated_cost + root_port->bif_path_cost))
goto set_port;
if ((bif->bif_designated_cost + bif->bif_path_cost) >
(root_port->bif_designated_cost + root_port->bif_path_cost))
continue;

if (bif->bif_designated_bridge <
root_port->bif_designated_bridge)
goto set_port;
if (bif->bif_designated_bridge >
root_port->bif_designated_bridge)
continue;

if (bif->bif_designated_port < root_port->bif_designated_port)
goto set_port;
if (bif->bif_designated_port > root_port->bif_designated_port)
continue;

if (bif->bif_port_id >= root_port->bif_port_id)
continue;
set_port:
root_port = bif;
}

sc->sc_root_port = root_port;
if (root_port == NULL) {
sc->sc_designated_root = sc->sc_bridge_id;
sc->sc_root_path_cost = 0;
} else {
sc->sc_designated_root = root_port->bif_designated_root;
sc->sc_root_path_cost = root_port->bif_designated_cost +
root_port->bif_path_cost;
}
}

static void
bstp_designated_port_selection(struct bridge_softc *sc)
{
struct bridge_iflist *bif;

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_designated_port(sc, bif))
goto designated;
if (bif->bif_designated_root != sc->sc_designated_root)
goto designated;

if (sc->sc_root_path_cost < bif->bif_designated_cost)
goto designated;
if (sc->sc_root_path_cost > bif->bif_designated_cost)
continue;

if (sc->sc_bridge_id < bif->bif_designated_bridge)
goto designated;
if (sc->sc_bridge_id > bif->bif_designated_bridge)
continue;

if (bif->bif_port_id > bif->bif_designated_port)
continue;
designated:
bstp_become_designated_port(sc, bif);
}
}

static void
bstp_become_designated_port(struct bridge_softc *sc, struct bridge_iflist *bif)
{
bif->bif_designated_root = sc->sc_designated_root;
bif->bif_designated_cost = sc->sc_root_path_cost;
bif->bif_designated_bridge = sc->sc_bridge_id;
bif->bif_designated_port = bif->bif_port_id;
}

static void
bstp_port_state_selection(struct bridge_softc *sc)
{
struct bridge_iflist *bif;

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bif == sc->sc_root_port) {
bif->bif_config_pending = 0;
bif->bif_topology_change_acknowledge = 0;
bstp_make_forwarding(sc, bif);
} else if (bstp_designated_port(sc, bif)) {
bstp_timer_stop(&bif->bif_message_age_timer);
bstp_make_forwarding(sc, bif);
} else {
bif->bif_config_pending = 0;
bif->bif_topology_change_acknowledge = 0;
bstp_make_blocking(sc, bif);
}
}
}

static void
bstp_make_forwarding(struct bridge_softc *sc,
struct bridge_iflist *bif)
{
if (bif->bif_state == BSTP_IFSTATE_BLOCKING) {
bstp_set_port_state(bif, BSTP_IFSTATE_LISTENING);
bstp_timer_start(&bif->bif_forward_delay_timer, 0);
}
}

static void
bstp_make_blocking(struct bridge_softc *sc, struct bridge_iflist *bif)
{
if ((bif->bif_state != BSTP_IFSTATE_DISABLED) &&
(bif->bif_state != BSTP_IFSTATE_BLOCKING)) {
if ((bif->bif_state == BSTP_IFSTATE_FORWARDING) ||
(bif->bif_state == BSTP_IFSTATE_LEARNING)) {
if (bif->bif_change_detection_enabled) {
bstp_topology_change_detection(sc);
}
}
bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
bstp_timer_stop(&bif->bif_forward_delay_timer);
}
}

static void
bstp_set_port_state(struct bridge_iflist *bif, uint8_t state)
{
bif->bif_state = state;
}

static void
bstp_topology_change_detection(struct bridge_softc *sc)
{
if (bstp_root_bridge(sc)) {
sc->sc_topology_change = 1;
bstp_timer_start(&sc->sc_topology_change_timer, 0);
} else if (!sc->sc_topology_change_detected) {
bstp_transmit_tcn(sc);
bstp_timer_start(&sc->sc_tcn_timer, 0);
}
sc->sc_topology_change_detected = 1;
}

static void
bstp_topology_change_acknowledged(struct bridge_softc *sc)
{
sc->sc_topology_change_detected = 0;
bstp_timer_stop(&sc->sc_tcn_timer);
}

static void
bstp_acknowledge_topology_change(struct bridge_softc *sc,
struct bridge_iflist *bif)
{
bif->bif_topology_change_acknowledge = 1;
bstp_transmit_config(sc, bif);
}

void
bstp_input(struct bridge_softc *sc, struct bridge_iflist *bif, struct mbuf *m)
{
struct ether_header *eh;
struct bstp_tbpdu tpdu;
struct bstp_cbpdu cpdu;
struct bstp_config_unit cu;
struct bstp_tcn_unit tu;
uint16_t len;

eh = mtod(m, struct ether_header *);

if ((bif->bif_flags & IFBIF_STP) == 0)
goto out;

len = ntohs(eh->ether_type);
if (len < sizeof(tpdu))
goto out;

m_adj(m, ETHER_HDR_LEN);

if (m->m_pkthdr.len > len)
m_adj(m, len - m->m_pkthdr.len);
if (m->m_len < sizeof(tpdu) &&
(m = m_pullup(m, sizeof(tpdu))) == NULL)
goto out;

memcpy(&tpdu, mtod(m, void *), sizeof(tpdu));

if (tpdu.tbu_dsap != LLC_8021D_LSAP ||
tpdu.tbu_ssap != LLC_8021D_LSAP ||
tpdu.tbu_ctl != LLC_UI)
goto out;
if (tpdu.tbu_protoid != 0 || tpdu.tbu_protover != 0)
goto out;

switch (tpdu.tbu_bpdutype) {
case BSTP_MSGTYPE_TCN:
tu.tu_message_type = tpdu.tbu_bpdutype;

BRIDGE_LOCK(sc);
bstp_received_tcn_bpdu(sc, bif, &tu);
BRIDGE_UNLOCK(sc);

break;
case BSTP_MSGTYPE_CFG:
if (m->m_len < sizeof(cpdu) &&
(m = m_pullup(m, sizeof(cpdu))) == NULL)
goto out;
memcpy(&cpdu, mtod(m, void *), sizeof(cpdu));

cu.cu_rootid =
(((uint64_t)ntohs(cpdu.cbu_rootpri)) << 48) |
(((uint64_t)cpdu.cbu_rootaddr[0]) << 40) |
(((uint64_t)cpdu.cbu_rootaddr[1]) << 32) |
(((uint64_t)cpdu.cbu_rootaddr[2]) << 24) |
(((uint64_t)cpdu.cbu_rootaddr[3]) << 16) |
(((uint64_t)cpdu.cbu_rootaddr[4]) << 8) |
(((uint64_t)cpdu.cbu_rootaddr[5]) << 0);

cu.cu_bridge_id =
(((uint64_t)ntohs(cpdu.cbu_bridgepri)) << 48) |
(((uint64_t)cpdu.cbu_bridgeaddr[0]) << 40) |
(((uint64_t)cpdu.cbu_bridgeaddr[1]) << 32) |
(((uint64_t)cpdu.cbu_bridgeaddr[2]) << 24) |
(((uint64_t)cpdu.cbu_bridgeaddr[3]) << 16) |
(((uint64_t)cpdu.cbu_bridgeaddr[4]) << 8) |
(((uint64_t)cpdu.cbu_bridgeaddr[5]) << 0);

cu.cu_root_path_cost = ntohl(cpdu.cbu_rootpathcost);
cu.cu_message_age = ntohs(cpdu.cbu_messageage);
cu.cu_max_age = ntohs(cpdu.cbu_maxage);
cu.cu_hello_time = ntohs(cpdu.cbu_hellotime);
cu.cu_forward_delay = ntohs(cpdu.cbu_forwarddelay);
cu.cu_port_id = ntohs(cpdu.cbu_portid);
cu.cu_message_type = cpdu.cbu_bpdutype;
cu.cu_topology_change_acknowledgment =
(cpdu.cbu_flags & BSTP_FLAG_TCA) ? 1 : 0;
cu.cu_topology_change =
(cpdu.cbu_flags & BSTP_FLAG_TC) ? 1 : 0;

BRIDGE_LOCK(sc);
bstp_received_config_bpdu(sc, bif, &cu);
BRIDGE_UNLOCK(sc);

break;
default:
goto out;
}

out:
m_freem(m);
return;
}

static void
bstp_received_config_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
struct bstp_config_unit *cu)
{
int root;

root = bstp_root_bridge(sc);

if (bif->bif_state != BSTP_IFSTATE_DISABLED) {
if (bstp_supersedes_port_info(sc, bif, cu)) {
bstp_record_config_information(sc, bif, cu);
bstp_configuration_update(sc);
bstp_port_state_selection(sc);

if ((bstp_root_bridge(sc) == 0) && root) {
bstp_timer_stop(&sc->sc_hello_timer);

if (sc->sc_topology_change_detected) {
bstp_timer_stop(
&sc->sc_topology_change_timer);
bstp_transmit_tcn(sc);
bstp_timer_start(&sc->sc_tcn_timer, 0);
}
}

if (bif == sc->sc_root_port) {
bstp_record_config_timeout_values(sc, cu);
bstp_config_bpdu_generation(sc);

if (cu->cu_topology_change_acknowledgment)
bstp_topology_change_acknowledged(sc);
}
} else if (bstp_designated_port(sc, bif))
bstp_transmit_config(sc, bif);
}
}

static void
bstp_received_tcn_bpdu(struct bridge_softc *sc, struct bridge_iflist *bif,
struct bstp_tcn_unit *tcn)
{
if (bif->bif_state != BSTP_IFSTATE_DISABLED &&
bstp_designated_port(sc, bif)) {
bstp_topology_change_detection(sc);
bstp_acknowledge_topology_change(sc, bif);
}
}

static void
bstp_hello_timer_expiry(struct bridge_softc *sc)
{
bstp_config_bpdu_generation(sc);
bstp_timer_start(&sc->sc_hello_timer, 0);
}

static void
bstp_message_age_timer_expiry(struct bridge_softc *sc,
struct bridge_iflist *bif)
{
int root;

root = bstp_root_bridge(sc);
bstp_become_designated_port(sc, bif);
bstp_configuration_update(sc);
bstp_port_state_selection(sc);

if ((bstp_root_bridge(sc)) && (root == 0)) {
sc->sc_max_age = sc->sc_bridge_max_age;
sc->sc_hello_time = sc->sc_bridge_hello_time;
sc->sc_forward_delay = sc->sc_bridge_forward_delay;

bstp_topology_change_detection(sc);
bstp_timer_stop(&sc->sc_tcn_timer);
bstp_config_bpdu_generation(sc);
bstp_timer_start(&sc->sc_hello_timer, 0);
}
}

static void
bstp_forward_delay_timer_expiry(struct bridge_softc *sc,
struct bridge_iflist *bif)
{
if (bif->bif_state == BSTP_IFSTATE_LISTENING) {
bstp_set_port_state(bif, BSTP_IFSTATE_LEARNING);
bstp_timer_start(&bif->bif_forward_delay_timer, 0);
} else if (bif->bif_state == BSTP_IFSTATE_LEARNING) {
bstp_set_port_state(bif, BSTP_IFSTATE_FORWARDING);
if (bstp_designated_for_some_port(sc) &&
bif->bif_change_detection_enabled)
bstp_topology_change_detection(sc);
}
}

static int
bstp_designated_for_some_port(struct bridge_softc *sc)
{

struct bridge_iflist *bif;

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bif->bif_designated_bridge == sc->sc_bridge_id)
return (1);
}
return (0);
}

static void
bstp_tcn_timer_expiry(struct bridge_softc *sc)
{
bstp_transmit_tcn(sc);
bstp_timer_start(&sc->sc_tcn_timer, 0);
}

static void
bstp_topology_change_timer_expiry(struct bridge_softc *sc)
{
sc->sc_topology_change_detected = 0;
sc->sc_topology_change = 0;
}

static void
bstp_hold_timer_expiry(struct bridge_softc *sc, struct bridge_iflist *bif)
{
if (bif->bif_config_pending)
bstp_transmit_config(sc, bif);
}

void
bstp_initialization(struct bridge_softc *sc)
{
struct bridge_iflist *bif, *mif;

mif = NULL;

BRIDGE_LOCK(sc);

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bif->bif_ifp->if_type != IFT_ETHER)
continue;
bif->bif_port_id = (bif->bif_priority << 8) |
(bif->bif_ifp->if_index & 0xff);

if (mif == NULL) {
mif = bif;
continue;
}
if (memcmp(CLLADDR(bif->bif_ifp->if_sadl),
CLLADDR(mif->bif_ifp->if_sadl), ETHER_ADDR_LEN) < 0) {
mif = bif;
continue;
}
}

if (mif == NULL) {
BRIDGE_UNLOCK(sc);
bstp_stop(sc);
return;
}

sc->sc_bridge_id =
(((uint64_t)sc->sc_bridge_priority) << 48) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[0]) << 40) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[1]) << 32) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[2]) << 24) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[3]) << 16) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[4]) << 8) |
(((uint64_t)(uint8_t)CLLADDR(mif->bif_ifp->if_sadl)[5]) << 0);

BRIDGE_UNLOCK(sc);

sc->sc_designated_root = sc->sc_bridge_id;
sc->sc_root_path_cost = 0;
sc->sc_root_port = NULL;

sc->sc_max_age = sc->sc_bridge_max_age;
sc->sc_hello_time = sc->sc_bridge_hello_time;
sc->sc_forward_delay = sc->sc_bridge_forward_delay;
sc->sc_topology_change_detected = 0;
sc->sc_topology_change = 0;
bstp_timer_stop(&sc->sc_tcn_timer);
bstp_timer_stop(&sc->sc_topology_change_timer);

if (callout_pending(&sc->sc_bstpcallout) == 0)
callout_reset(&sc->sc_bstpcallout, hz,
bstp_tick, sc);

BRIDGE_LOCK(sc);

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if (bif->bif_flags & IFBIF_STP)
bstp_enable_port(sc, bif);
else
bstp_disable_port(sc, bif);
}

bstp_port_state_selection(sc);
bstp_config_bpdu_generation(sc);
bstp_timer_start(&sc->sc_hello_timer, 0);

BRIDGE_UNLOCK(sc);
}

void
bstp_stop(struct bridge_softc *sc)
{
struct bridge_iflist *bif;

BRIDGE_LOCK(sc);
BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
bstp_timer_stop(&bif->bif_hold_timer);
bstp_timer_stop(&bif->bif_message_age_timer);
bstp_timer_stop(&bif->bif_forward_delay_timer);
}
BRIDGE_UNLOCK(sc);

callout_stop(&sc->sc_bstpcallout);

bstp_timer_stop(&sc->sc_topology_change_timer);
bstp_timer_stop(&sc->sc_tcn_timer);
bstp_timer_stop(&sc->sc_hello_timer);

}

static void
bstp_initialize_port(struct bridge_softc *sc, struct bridge_iflist *bif)
{
bstp_become_designated_port(sc, bif);
bstp_set_port_state(bif, BSTP_IFSTATE_BLOCKING);
bif->bif_topology_change_acknowledge = 0;
bif->bif_config_pending = 0;
bif->bif_change_detection_enabled = 1;
bstp_timer_stop(&bif->bif_message_age_timer);
bstp_timer_stop(&bif->bif_forward_delay_timer);
bstp_timer_stop(&bif->bif_hold_timer);
}

static void
bstp_enable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
{
bstp_initialize_port(sc, bif);
bstp_port_state_selection(sc);
}

static void
bstp_disable_port(struct bridge_softc *sc, struct bridge_iflist *bif)
{
int root;

root = bstp_root_bridge(sc);
bstp_become_designated_port(sc, bif);
bstp_set_port_state(bif, BSTP_IFSTATE_DISABLED);
bif->bif_topology_change_acknowledge = 0;
bif->bif_config_pending = 0;
bstp_timer_stop(&bif->bif_message_age_timer);
bstp_timer_stop(&bif->bif_forward_delay_timer);
bstp_configuration_update(sc);
bstp_port_state_selection(sc);

if (bstp_root_bridge(sc) && (root == 0)) {
sc->sc_max_age = sc->sc_bridge_max_age;
sc->sc_hello_time = sc->sc_bridge_hello_time;
sc->sc_forward_delay = sc->sc_bridge_forward_delay;

bstp_topology_change_detection(sc);
bstp_timer_stop(&sc->sc_tcn_timer);
bstp_config_bpdu_generation(sc);
bstp_timer_start(&sc->sc_hello_timer, 0);
}
}

#if notused
static void
bstp_set_bridge_priority(struct bridge_softc *sc, uint64_t new_bridge_id)
{
struct bridge_iflist *bif;
int root;

root = bstp_root_bridge(sc);

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_designated_port(sc, bif))
bif->bif_designated_bridge = new_bridge_id;
}

sc->sc_bridge_id = new_bridge_id;

bstp_configuration_update(sc);
bstp_port_state_selection(sc);

if (bstp_root_bridge(sc) && (root == 0)) {
sc->sc_max_age = sc->sc_bridge_max_age;
sc->sc_hello_time = sc->sc_bridge_hello_time;
sc->sc_forward_delay = sc->sc_bridge_forward_delay;

bstp_topology_change_detection(sc);
bstp_timer_stop(&sc->sc_tcn_timer);
bstp_config_bpdu_generation(sc);
bstp_timer_start(&sc->sc_hello_timer, 0);
}
}

static void
bstp_set_port_priority(struct bridge_softc *sc, struct bridge_iflist *bif,
uint16_t new_port_id)
{
if (bstp_designated_port(sc, bif))
bif->bif_designated_port = new_port_id;

bif->bif_port_id = new_port_id;

if ((sc->sc_bridge_id == bif->bif_designated_bridge) &&
(bif->bif_port_id < bif->bif_designated_port)) {
bstp_become_designated_port(sc, bif);
bstp_port_state_selection(sc);
}
}

static void
bstp_set_path_cost(struct bridge_softc *sc, struct bridge_iflist *bif,
uint32_t path_cost)
{
bif->bif_path_cost = path_cost;
bstp_configuration_update(sc);
bstp_port_state_selection(sc);
}
#endif

static void
bstp_ifupdstatus(struct bridge_softc *sc, struct bridge_iflist *bif)
{
struct ifnet *ifp = bif->bif_ifp;

if (ifp->if_flags & IFF_UP) {
switch (ifp->if_link_state) {
case LINK_STATE_UNKNOWN:
/*
* Just enable the port if the link state is
* unknown.
*/
if (bif->bif_state == BSTP_IFSTATE_DISABLED)
bstp_enable_port(sc, bif);
break;

case LINK_STATE_UP:
if (bif->bif_state == BSTP_IFSTATE_DISABLED)
bstp_enable_port(sc, bif);
break;

case LINK_STATE_DOWN:
if (bif->bif_state != BSTP_IFSTATE_DISABLED)
bstp_disable_port(sc, bif);
break;
}
return;
}

if (bif->bif_state != BSTP_IFSTATE_DISABLED)
bstp_disable_port(sc, bif);
}

static void
bstp_tick(void *arg)
{
struct bridge_softc *sc = arg;
struct bridge_iflist *bif;

BRIDGE_LOCK(sc);

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
/*
* XXX This can cause a lag in "link does away"
* XXX and "spanning tree gets updated". We need
* XXX come sort of callback from the link state
* XXX update code to kick spanning tree.
* XXX [email protected]
*/
bstp_ifupdstatus(sc, bif);
}

if (bstp_timer_expired(&sc->sc_hello_timer, sc->sc_hello_time))
bstp_hello_timer_expiry(sc);

if (bstp_timer_expired(&sc->sc_tcn_timer, sc->sc_bridge_hello_time))
bstp_tcn_timer_expiry(sc);

if (bstp_timer_expired(&sc->sc_topology_change_timer,
sc->sc_topology_change_time))
bstp_topology_change_timer_expiry(sc);

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_timer_expired(&bif->bif_message_age_timer,
sc->sc_max_age))
bstp_message_age_timer_expiry(sc, bif);
}

BRIDGE_IFLIST_WRITER_FOREACH(bif, sc) {
if ((bif->bif_flags & IFBIF_STP) == 0)
continue;
if (bstp_timer_expired(&bif->bif_forward_delay_timer,
sc->sc_forward_delay))
bstp_forward_delay_timer_expiry(sc, bif);

if (bstp_timer_expired(&bif->bif_hold_timer,
sc->sc_hold_time))
bstp_hold_timer_expiry(sc, bif);
}

if (sc->sc_if.if_flags & IFF_RUNNING)
callout_reset(&sc->sc_bstpcallout, hz, bstp_tick, sc);

BRIDGE_UNLOCK(sc);
}

static void
bstp_timer_start(struct bridge_timer *t, uint16_t v)
{
t->value = v;
t->active = 1;
}

static void
bstp_timer_stop(struct bridge_timer *t)
{
t->value = 0;
t->active = 0;
}

static int
bstp_timer_expired(struct bridge_timer *t, uint16_t v)
{
if (t->active == 0)
return (0);
t->value += BSTP_TICK_VAL;
if (t->value >= v) {
bstp_timer_stop(t);
return (1);
}
return (0);

}