link.c

linux 内核源代码

		err("Attempt to delete non-existent link\n");
		return;
	}

	dbg("tipc_link_delete()\n");

	k_cancel_timer(&l_ptr->timer);

	tipc_node_lock(l_ptr->owner);
	tipc_link_reset(l_ptr);
	tipc_node_detach_link(l_ptr->owner, l_ptr);
	tipc_link_stop(l_ptr);
	list_del_init(&l_ptr->link_list);
	if (LINK_LOG_BUF_SIZE)
		kfree(l_ptr->print_buf.buf);
	tipc_node_unlock(l_ptr->owner);
	k_term_timer(&l_ptr->timer);
	kfree(l_ptr);
}

void tipc_link_start(struct link *l_ptr)
{
	dbg("tipc_link_start %x\n", l_ptr);
	link_state_event(l_ptr, STARTING_EVT);
}

/**
 * link_schedule_port - schedule port for deferred sending
 * @l_ptr: pointer to link
 * @origport: reference to sending port
 * @sz: amount of data to be sent
 *
 * Schedules port for renewed sending of messages after link congestion
 * has abated.
 */

static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
{
	struct port *p_ptr;

	spin_lock_bh(&tipc_port_list_lock);
	p_ptr = tipc_port_lock(origport);
	if (p_ptr) {
		if (!p_ptr->wakeup)
			goto exit;
		if (!list_empty(&p_ptr->wait_list))
			goto exit;
		p_ptr->congested_link = l_ptr;
		p_ptr->publ.congested = 1;
		p_ptr->waiting_pkts = 1 + ((sz - 1) / link_max_pkt(l_ptr));
		list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
		l_ptr->stats.link_congs++;
exit:
		tipc_port_unlock(p_ptr);
	}
	spin_unlock_bh(&tipc_port_list_lock);
	return -ELINKCONG;
}

void tipc_link_wakeup_ports(struct link *l_ptr, int all)
{
	struct port *p_ptr;
	struct port *temp_p_ptr;
	int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;

	if (all)
		win = 100000;
	if (win <= 0)
		return;
	if (!spin_trylock_bh(&tipc_port_list_lock))
		return;
	if (link_congested(l_ptr))
		goto exit;
	list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
				 wait_list) {
		if (win <= 0)
			break;
		list_del_init(&p_ptr->wait_list);
		p_ptr->congested_link = NULL;
		spin_lock_bh(p_ptr->publ.lock);
		p_ptr->publ.congested = 0;
		p_ptr->wakeup(&p_ptr->publ);
		win -= p_ptr->waiting_pkts;
		spin_unlock_bh(p_ptr->publ.lock);
	}

exit:
	spin_unlock_bh(&tipc_port_list_lock);
}

/**
 * link_release_outqueue - purge link's outbound message queue
 * @l_ptr: pointer to link
 */

static void link_release_outqueue(struct link *l_ptr)
{
	struct sk_buff *buf = l_ptr->first_out;
	struct sk_buff *next;

	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	l_ptr->first_out = NULL;
	l_ptr->out_queue_size = 0;
}

/**
 * tipc_link_reset_fragments - purge link's inbound message fragments queue
 * @l_ptr: pointer to link
 */

void tipc_link_reset_fragments(struct link *l_ptr)
{
	struct sk_buff *buf = l_ptr->defragm_buf;
	struct sk_buff *next;

	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	l_ptr->defragm_buf = NULL;
}

/**
 * tipc_link_stop - purge all inbound and outbound messages associated with link
 * @l_ptr: pointer to link
 */

void tipc_link_stop(struct link *l_ptr)
{
	struct sk_buff *buf;
	struct sk_buff *next;

	buf = l_ptr->oldest_deferred_in;
	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}

	buf = l_ptr->first_out;
	while (buf) {
		next = buf->next;
		buf_discard(buf);
		buf = next;
	}

	tipc_link_reset_fragments(l_ptr);

	buf_discard(l_ptr->proto_msg_queue);
	l_ptr->proto_msg_queue = NULL;
}

#if 0

/* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */

static void link_recv_event(struct link_event *ev)
{
	ev->fcn(ev->addr, ev->name, ev->up);
	kfree(ev);
}

static void link_send_event(void (*fcn)(u32 a, char *n, int up),
			    struct link *l_ptr, int up)
{
	struct link_event *ev;

	ev = kmalloc(sizeof(*ev), GFP_ATOMIC);
	if (!ev) {
		warn("Link event allocation failure\n");
		return;
	}
	ev->addr = l_ptr->addr;
	ev->up = up;
	ev->fcn = fcn;
	memcpy(ev->name, l_ptr->name, TIPC_MAX_LINK_NAME);
	tipc_k_signal((Handler)link_recv_event, (unsigned long)ev);
}

#else

#define link_send_event(fcn, l_ptr, up) do { } while (0)

#endif

void tipc_link_reset(struct link *l_ptr)
{
	struct sk_buff *buf;
	u32 prev_state = l_ptr->state;
	u32 checkpoint = l_ptr->next_in_no;
	int was_active_link = tipc_link_is_active(l_ptr);

	msg_set_session(l_ptr->pmsg, msg_session(l_ptr->pmsg) + 1);

	/* Link is down, accept any session: */
	l_ptr->peer_session = 0;

	/* Prepare for max packet size negotiation */
	link_init_max_pkt(l_ptr);

	l_ptr->state = RESET_UNKNOWN;
	dbg_link_state("Resetting Link\n");

	if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
		return;

	tipc_node_link_down(l_ptr->owner, l_ptr);
	tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
#if 0
	tipc_printf(TIPC_CONS, "\nReset link <%s>\n", l_ptr->name);
	dbg_link_dump();
#endif
	if (was_active_link && tipc_node_has_active_links(l_ptr->owner) &&
	    l_ptr->owner->permit_changeover) {
		l_ptr->reset_checkpoint = checkpoint;
		l_ptr->exp_msg_count = START_CHANGEOVER;
	}

	/* Clean up all queues: */

	link_release_outqueue(l_ptr);
	buf_discard(l_ptr->proto_msg_queue);
	l_ptr->proto_msg_queue = NULL;
	buf = l_ptr->oldest_deferred_in;
	while (buf) {
		struct sk_buff *next = buf->next;
		buf_discard(buf);
		buf = next;
	}
	if (!list_empty(&l_ptr->waiting_ports))
		tipc_link_wakeup_ports(l_ptr, 1);

	l_ptr->retransm_queue_head = 0;
	l_ptr->retransm_queue_size = 0;
	l_ptr->last_out = NULL;
	l_ptr->first_out = NULL;
	l_ptr->next_out = NULL;
	l_ptr->unacked_window = 0;
	l_ptr->checkpoint = 1;
	l_ptr->next_out_no = 1;
	l_ptr->deferred_inqueue_sz = 0;
	l_ptr->oldest_deferred_in = NULL;
	l_ptr->newest_deferred_in = NULL;
	l_ptr->fsm_msg_cnt = 0;
	l_ptr->stale_count = 0;
	link_reset_statistics(l_ptr);

	link_send_event(tipc_cfg_link_event, l_ptr, 0);
	if (!in_own_cluster(l_ptr->addr))
		link_send_event(tipc_disc_link_event, l_ptr, 0);
}


static void link_activate(struct link *l_ptr)
{
	l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
	tipc_node_link_up(l_ptr->owner, l_ptr);
	tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
	link_send_event(tipc_cfg_link_event, l_ptr, 1);
	if (!in_own_cluster(l_ptr->addr))
		link_send_event(tipc_disc_link_event, l_ptr, 1);
}

/**
 * link_state_event - link finite state machine
 * @l_ptr: pointer to link
 * @event: state machine event to process
 */

static void link_state_event(struct link *l_ptr, unsigned event)
{
	struct link *other;
	u32 cont_intv = l_ptr->continuity_interval;

	if (!l_ptr->started && (event != STARTING_EVT))
		return;		/* Not yet. */

	if (link_blocked(l_ptr)) {
		if (event == TIMEOUT_EVT) {
			link_set_timer(l_ptr, cont_intv);
		}
		return;	  /* Changeover going on */
	}
	dbg_link("STATE_EV: <%s> ", l_ptr->name);

	switch (l_ptr->state) {
	case WORKING_WORKING:
		dbg_link("WW/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
			/* fall through */
		case ACTIVATE_MSG:
			dbg_link("ACT\n");
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM ");
			if (l_ptr->next_in_no != l_ptr->checkpoint) {
				l_ptr->checkpoint = l_ptr->next_in_no;
				if (tipc_bclink_acks_missing(l_ptr->owner)) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 0, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				} else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 1, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				}
				link_set_timer(l_ptr, cont_intv);
				break;
			}
			dbg_link(" -> WU\n");
			l_ptr->state = WORKING_UNKNOWN;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv / 4);
			break;
		case RESET_MSG:
			dbg_link("RES -> RR\n");
			info("Resetting link <%s>, requested by peer\n",
			     l_ptr->name);
			tipc_link_reset(l_ptr);
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		default:
			err("Unknown link event %u in WW state\n", event);
		}
		break;
	case WORKING_UNKNOWN:
		dbg_link("WU/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
		case ACTIVATE_MSG:
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES -> RR\n");
			info("Resetting link <%s>, requested by peer "
			     "while probing\n", l_ptr->name);
			tipc_link_reset(l_ptr);
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM ");
			if (l_ptr->next_in_no != l_ptr->checkpoint) {
				dbg_link("-> WW \n");
				l_ptr->state = WORKING_WORKING;
				l_ptr->fsm_msg_cnt = 0;
				l_ptr->checkpoint = l_ptr->next_in_no;
				if (tipc_bclink_acks_missing(l_ptr->owner)) {
					tipc_link_send_proto_msg(l_ptr, STATE_MSG,
								 0, 0, 0, 0, 0);
					l_ptr->fsm_msg_cnt++;
				}
				link_set_timer(l_ptr, cont_intv);
			} else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
				dbg_link("Probing %u/%u,timer = %u ms)\n",
					 l_ptr->fsm_msg_cnt, l_ptr->abort_limit,
					 cont_intv / 4);
				tipc_link_send_proto_msg(l_ptr, STATE_MSG,
							 1, 0, 0, 0, 0);
				l_ptr->fsm_msg_cnt++;
				link_set_timer(l_ptr, cont_intv / 4);
			} else {	/* Link has failed */
				dbg_link("-> RU (%u probes unanswered)\n",
					 l_ptr->fsm_msg_cnt);
				warn("Resetting link <%s>, peer not responding\n",
				     l_ptr->name);
				tipc_link_reset(l_ptr);
				l_ptr->state = RESET_UNKNOWN;
				l_ptr->fsm_msg_cnt = 0;
				tipc_link_send_proto_msg(l_ptr, RESET_MSG,
							 0, 0, 0, 0, 0);
				l_ptr->fsm_msg_cnt++;
				link_set_timer(l_ptr, cont_intv);
			}
			break;
		default:
			err("Unknown link event %u in WU state\n", event);
		}
		break;
	case RESET_UNKNOWN:
		dbg_link("RU/");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-\n");
			break;
		case ACTIVATE_MSG:
			other = l_ptr->owner->active_links[0];
			if (other && link_working_unknown(other)) {
				dbg_link("ACT\n");
				break;
			}
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_activate(l_ptr);
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES \n");
			dbg_link(" -> RR\n");
			l_ptr->state = RESET_RESET;
			l_ptr->fsm_msg_cnt = 0;
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case STARTING_EVT:
			dbg_link("START-");
			l_ptr->started = 1;
			/* fall through */
		case TIMEOUT_EVT:
			dbg_link("TIM \n");
			tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		default:
			err("Unknown link event %u in RU state\n", event);
		}
		break;
	case RESET_RESET:
		dbg_link("RR/ ");
		switch (event) {
		case TRAFFIC_MSG_EVT:
			dbg_link("TRF-");
			/* fall through */
		case ACTIVATE_MSG:
			other = l_ptr->owner->active_links[0];
			if (other && link_working_unknown(other)) {
				dbg_link("ACT\n");
				break;
			}
			dbg_link("ACT -> WW\n");
			l_ptr->state = WORKING_WORKING;
			l_ptr->fsm_msg_cnt = 0;
			link_activate(l_ptr);
			tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			break;
		case RESET_MSG:
			dbg_link("RES\n");
			break;
		case TIMEOUT_EVT:
			dbg_link("TIM\n");
			tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
			l_ptr->fsm_msg_cnt++;
			link_set_timer(l_ptr, cont_intv);
			dbg_link("fsm_msg_cnt %u\n", l_ptr->fsm_msg_cnt);
			break;
		default:
			err("Unknown link event %u in RR state\n", event);
		}
		break;
	default:
		err("Unknown link state %u/%u\n", l_ptr->state, event);
	}
}

/*
 * link_bundle_buf(): Append contents of a buffer to
 * the tail of an existing one.
 */

static int link_bundle_buf(struct link *l_ptr,
			   struct sk_buff *bundler,
			   struct sk_buff *buf)
{
	struct tipc_msg *bundler_msg = buf_msg(bundler);
	struct tipc_msg *msg = buf_msg(buf);
	u32 size = msg_size(msg);
	u32 bundle_size = msg_size(bundler_msg);
	u32 to_pos = align(bundle_size);
	u32 pad = to_pos - bundle_size;

	if (msg_user(bundler_msg) != MSG_BUNDLER)