bearer.c

linux 内核源代码

}

void tipc_bearer_remove_dest(struct bearer *b_ptr, u32 dest)
{
	tipc_nmap_remove(&b_ptr->nodes, dest);
	tipc_disc_update_link_req(b_ptr->link_req);
	tipc_bcbearer_sort();
}

/*
 * bearer_push(): Resolve bearer congestion. Force the waiting
 * links to push out their unsent packets, one packet per link
 * per iteration, until all packets are gone or congestion reoccurs.
 * 'tipc_net_lock' is read_locked when this function is called
 * bearer.lock must be taken before calling
 * Returns binary true(1) ore false(0)
 */
static int bearer_push(struct bearer *b_ptr)
{
	u32 res = TIPC_OK;
	struct link *ln, *tln;

	if (b_ptr->publ.blocked)
		return 0;

	while (!list_empty(&b_ptr->cong_links) && (res != PUSH_FAILED)) {
		list_for_each_entry_safe(ln, tln, &b_ptr->cong_links, link_list) {
			res = tipc_link_push_packet(ln);
			if (res == PUSH_FAILED)
				break;
			if (res == PUSH_FINISHED)
				list_move_tail(&ln->link_list, &b_ptr->links);
		}
	}
	return list_empty(&b_ptr->cong_links);
}

void tipc_bearer_lock_push(struct bearer *b_ptr)
{
	int res;

	spin_lock_bh(&b_ptr->publ.lock);
	res = bearer_push(b_ptr);
	spin_unlock_bh(&b_ptr->publ.lock);
	if (res)
		tipc_bcbearer_push();
}


/*
 * Interrupt enabling new requests after bearer congestion or blocking:
 * See bearer_send().
 */
void tipc_continue(struct tipc_bearer *tb_ptr)
{
	struct bearer *b_ptr = (struct bearer *)tb_ptr;

	spin_lock_bh(&b_ptr->publ.lock);
	b_ptr->continue_count++;
	if (!list_empty(&b_ptr->cong_links))
		tipc_k_signal((Handler)tipc_bearer_lock_push, (unsigned long)b_ptr);
	b_ptr->publ.blocked = 0;
	spin_unlock_bh(&b_ptr->publ.lock);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here
 * bearer.lock is busy
 */

static void tipc_bearer_schedule_unlocked(struct bearer *b_ptr, struct link *l_ptr)
{
	list_move_tail(&l_ptr->link_list, &b_ptr->cong_links);
}

/*
 * Schedule link for sending of messages after the bearer
 * has been deblocked by 'continue()'. This method is called
 * when somebody tries to send a message via this link while
 * the bearer is congested. 'tipc_net_lock' is in read_lock here,
 * bearer.lock is free
 */

void tipc_bearer_schedule(struct bearer *b_ptr, struct link *l_ptr)
{
	spin_lock_bh(&b_ptr->publ.lock);
	tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
	spin_unlock_bh(&b_ptr->publ.lock);
}


/*
 * tipc_bearer_resolve_congestion(): Check if there is bearer congestion,
 * and if there is, try to resolve it before returning.
 * 'tipc_net_lock' is read_locked when this function is called
 */
int tipc_bearer_resolve_congestion(struct bearer *b_ptr, struct link *l_ptr)
{
	int res = 1;

	if (list_empty(&b_ptr->cong_links))
		return 1;
	spin_lock_bh(&b_ptr->publ.lock);
	if (!bearer_push(b_ptr)) {
		tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
		res = 0;
	}
	spin_unlock_bh(&b_ptr->publ.lock);
	return res;
}


/**
 * tipc_enable_bearer - enable bearer with the given name
 */

int tipc_enable_bearer(const char *name, u32 bcast_scope, u32 priority)
{
	struct bearer *b_ptr;
	struct media *m_ptr;
	struct bearer_name b_name;
	char addr_string[16];
	u32 bearer_id;
	u32 with_this_prio;
	u32 i;
	int res = -EINVAL;

	if (tipc_mode != TIPC_NET_MODE) {
		warn("Bearer <%s> rejected, not supported in standalone mode\n",
		     name);
		return -ENOPROTOOPT;
	}
	if (!bearer_name_validate(name, &b_name)) {
		warn("Bearer <%s> rejected, illegal name\n", name);
		return -EINVAL;
	}
	if (!tipc_addr_domain_valid(bcast_scope) ||
	    !in_scope(bcast_scope, tipc_own_addr)) {
		warn("Bearer <%s> rejected, illegal broadcast scope\n", name);
		return -EINVAL;
	}
	if ((priority < TIPC_MIN_LINK_PRI ||
	     priority > TIPC_MAX_LINK_PRI) &&
	    (priority != TIPC_MEDIA_LINK_PRI)) {
		warn("Bearer <%s> rejected, illegal priority\n", name);
		return -EINVAL;
	}

	write_lock_bh(&tipc_net_lock);

	m_ptr = media_find(b_name.media_name);
	if (!m_ptr) {
		warn("Bearer <%s> rejected, media <%s> not registered\n", name,
		     b_name.media_name);
		goto failed;
	}

	if (priority == TIPC_MEDIA_LINK_PRI)
		priority = m_ptr->priority;

restart:
	bearer_id = MAX_BEARERS;
	with_this_prio = 1;
	for (i = MAX_BEARERS; i-- != 0; ) {
		if (!tipc_bearers[i].active) {
			bearer_id = i;
			continue;
		}
		if (!strcmp(name, tipc_bearers[i].publ.name)) {
			warn("Bearer <%s> rejected, already enabled\n", name);
			goto failed;
		}
		if ((tipc_bearers[i].priority == priority) &&
		    (++with_this_prio > 2)) {
			if (priority-- == 0) {
				warn("Bearer <%s> rejected, duplicate priority\n",
				     name);
				goto failed;
			}
			warn("Bearer <%s> priority adjustment required %u->%u\n",
			     name, priority + 1, priority);
			goto restart;
		}
	}
	if (bearer_id >= MAX_BEARERS) {
		warn("Bearer <%s> rejected, bearer limit reached (%u)\n",
		     name, MAX_BEARERS);
		goto failed;
	}

	b_ptr = &tipc_bearers[bearer_id];
	memset(b_ptr, 0, sizeof(struct bearer));

	strcpy(b_ptr->publ.name, name);
	res = m_ptr->enable_bearer(&b_ptr->publ);
	if (res) {
		warn("Bearer <%s> rejected, enable failure (%d)\n", name, -res);
		goto failed;
	}

	b_ptr->identity = bearer_id;
	b_ptr->media = m_ptr;
	b_ptr->net_plane = bearer_id + 'A';
	b_ptr->active = 1;
	b_ptr->detect_scope = bcast_scope;
	b_ptr->priority = priority;
	INIT_LIST_HEAD(&b_ptr->cong_links);
	INIT_LIST_HEAD(&b_ptr->links);
	if (m_ptr->bcast) {
		b_ptr->link_req = tipc_disc_init_link_req(b_ptr, &m_ptr->bcast_addr,
							  bcast_scope, 2);
	}
	spin_lock_init(&b_ptr->publ.lock);
	write_unlock_bh(&tipc_net_lock);
	info("Enabled bearer <%s>, discovery domain %s, priority %u\n",
	     name, addr_string_fill(addr_string, bcast_scope), priority);
	return 0;
failed:
	write_unlock_bh(&tipc_net_lock);
	return res;
}

/**
 * tipc_block_bearer(): Block the bearer with the given name,
 *                      and reset all its links
 */

int tipc_block_bearer(const char *name)
{
	struct bearer *b_ptr = NULL;
	struct link *l_ptr;
	struct link *temp_l_ptr;

	read_lock_bh(&tipc_net_lock);
	b_ptr = bearer_find(name);
	if (!b_ptr) {
		warn("Attempt to block unknown bearer <%s>\n", name);
		read_unlock_bh(&tipc_net_lock);
		return -EINVAL;
	}

	info("Blocking bearer <%s>\n", name);
	spin_lock_bh(&b_ptr->publ.lock);
	b_ptr->publ.blocked = 1;
	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
		struct node *n_ptr = l_ptr->owner;

		spin_lock_bh(&n_ptr->lock);
		tipc_link_reset(l_ptr);
		spin_unlock_bh(&n_ptr->lock);
	}
	spin_unlock_bh(&b_ptr->publ.lock);
	read_unlock_bh(&tipc_net_lock);
	return TIPC_OK;
}

/**
 * bearer_disable -
 *
 * Note: This routine assumes caller holds tipc_net_lock.
 */

static int bearer_disable(const char *name)
{
	struct bearer *b_ptr;
	struct link *l_ptr;
	struct link *temp_l_ptr;

	b_ptr = bearer_find(name);
	if (!b_ptr) {
		warn("Attempt to disable unknown bearer <%s>\n", name);
		return -EINVAL;
	}

	info("Disabling bearer <%s>\n", name);
	tipc_disc_stop_link_req(b_ptr->link_req);
	spin_lock_bh(&b_ptr->publ.lock);
	b_ptr->link_req = NULL;
	b_ptr->publ.blocked = 1;
	if (b_ptr->media->disable_bearer) {
		spin_unlock_bh(&b_ptr->publ.lock);
		write_unlock_bh(&tipc_net_lock);
		b_ptr->media->disable_bearer(&b_ptr->publ);
		write_lock_bh(&tipc_net_lock);
		spin_lock_bh(&b_ptr->publ.lock);
	}
	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
		tipc_link_delete(l_ptr);
	}
	spin_unlock_bh(&b_ptr->publ.lock);
	memset(b_ptr, 0, sizeof(struct bearer));
	return TIPC_OK;
}

int tipc_disable_bearer(const char *name)
{
	int res;

	write_lock_bh(&tipc_net_lock);
	res = bearer_disable(name);
	write_unlock_bh(&tipc_net_lock);
	return res;
}



int tipc_bearer_init(void)
{
	int res;

	write_lock_bh(&tipc_net_lock);
	tipc_bearers = kcalloc(MAX_BEARERS, sizeof(struct bearer), GFP_ATOMIC);
	media_list = kcalloc(MAX_MEDIA, sizeof(struct media), GFP_ATOMIC);
	if (tipc_bearers && media_list) {
		res = TIPC_OK;
	} else {
		kfree(tipc_bearers);
		kfree(media_list);
		tipc_bearers = NULL;
		media_list = NULL;
		res = -ENOMEM;
	}
	write_unlock_bh(&tipc_net_lock);
	return res;
}

void tipc_bearer_stop(void)
{
	u32 i;

	if (!tipc_bearers)
		return;

	for (i = 0; i < MAX_BEARERS; i++) {
		if (tipc_bearers[i].active)
			tipc_bearers[i].publ.blocked = 1;
	}
	for (i = 0; i < MAX_BEARERS; i++) {
		if (tipc_bearers[i].active)
			bearer_disable(tipc_bearers[i].publ.name);
	}
	kfree(tipc_bearers);
	kfree(media_list);
	tipc_bearers = NULL;
	media_list = NULL;
	media_count = 0;
}