node.c

linux 内核源代码

		return;
	}

	if (n_ptr->bclink.supported) {
		tipc_nmap_add(&tipc_cltr_bcast_nodes, n_ptr->addr);
		if (n_ptr->addr < tipc_own_addr)
			tipc_own_tag++;
	}

	/* Case 3 (see above) */
	tipc_net_send_external_routes(n_ptr->addr);
	tipc_cltr_send_slave_routes(c_ptr, n_ptr->addr);
	tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, LOWEST_SLAVE,
				  tipc_highest_allowed_slave);
}

static void node_lost_contact(struct node *n_ptr)
{
	struct cluster *c_ptr;
	struct node_subscr *ns, *tns;
	char addr_string[16];
	u32 i;

	/* Clean up broadcast reception remains */
	n_ptr->bclink.gap_after = n_ptr->bclink.gap_to = 0;
	while (n_ptr->bclink.deferred_head) {
		struct sk_buff* buf = n_ptr->bclink.deferred_head;
		n_ptr->bclink.deferred_head = buf->next;
		buf_discard(buf);
	}
	if (n_ptr->bclink.defragm) {
		buf_discard(n_ptr->bclink.defragm);
		n_ptr->bclink.defragm = NULL;
	}
	if (in_own_cluster(n_ptr->addr) && n_ptr->bclink.supported) {
		tipc_bclink_acknowledge(n_ptr, mod(n_ptr->bclink.acked + 10000));
	}

	/* Update routing tables */
	if (is_slave(tipc_own_addr)) {
		tipc_net_remove_as_router(n_ptr->addr);
	} else {
		if (!in_own_cluster(n_ptr->addr)) {
			/* Case 4 (see above) */
			c_ptr = tipc_cltr_find(tipc_own_addr);
			tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
						   tipc_max_nodes);
		} else {
			/* Case 5 (see above) */
			c_ptr = tipc_cltr_find(n_ptr->addr);
			if (is_slave(n_ptr->addr)) {
				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr, 1,
							   tipc_max_nodes);
			} else {
				if (n_ptr->bclink.supported) {
					tipc_nmap_remove(&tipc_cltr_bcast_nodes,
							 n_ptr->addr);
					if (n_ptr->addr < tipc_own_addr)
						tipc_own_tag--;
				}
				tipc_net_remove_as_router(n_ptr->addr);
				tipc_cltr_bcast_lost_route(c_ptr, n_ptr->addr,
							   LOWEST_SLAVE,
							   tipc_highest_allowed_slave);
			}
		}
	}
	if (tipc_node_has_active_routes(n_ptr))
		return;

	info("Lost contact with %s\n",
	     addr_string_fill(addr_string, n_ptr->addr));

	/* Abort link changeover */
	for (i = 0; i < MAX_BEARERS; i++) {
		struct link *l_ptr = n_ptr->links[i];
		if (!l_ptr)
			continue;
		l_ptr->reset_checkpoint = l_ptr->next_in_no;
		l_ptr->exp_msg_count = 0;
		tipc_link_reset_fragments(l_ptr);
	}

	/* Notify subscribers */
	list_for_each_entry_safe(ns, tns, &n_ptr->nsub, nodesub_list) {
		ns->node = NULL;
		list_del_init(&ns->nodesub_list);
		tipc_k_signal((Handler)ns->handle_node_down,
			      (unsigned long)ns->usr_handle);
	}
}

/**
 * tipc_node_select_next_hop - find the next-hop node for a message
 *
 * Called by when cluster local lookup has failed.
 */

struct node *tipc_node_select_next_hop(u32 addr, u32 selector)
{
	struct node *n_ptr;
	u32 router_addr;

	if (!tipc_addr_domain_valid(addr))
		return NULL;

	/* Look for direct link to destination processsor */
	n_ptr = tipc_node_find(addr);
	if (n_ptr && tipc_node_has_active_links(n_ptr))
		return n_ptr;

	/* Cluster local system nodes *must* have direct links */
	if (!is_slave(addr) && in_own_cluster(addr))
		return NULL;

	/* Look for cluster local router with direct link to node */
	router_addr = tipc_node_select_router(n_ptr, selector);
	if (router_addr)
		return tipc_node_select(router_addr, selector);

	/* Slave nodes can only be accessed within own cluster via a
	   known router with direct link -- if no router was found,give up */
	if (is_slave(addr))
		return NULL;

	/* Inter zone/cluster -- find any direct link to remote cluster */
	addr = tipc_addr(tipc_zone(addr), tipc_cluster(addr), 0);
	n_ptr = tipc_net_select_remote_node(addr, selector);
	if (n_ptr && tipc_node_has_active_links(n_ptr))
		return n_ptr;

	/* Last resort -- look for any router to anywhere in remote zone */
	router_addr =  tipc_net_select_router(addr, selector);
	if (router_addr)
		return tipc_node_select(router_addr, selector);

	return NULL;
}

/**
 * tipc_node_select_router - select router to reach specified node
 *
 * Uses a deterministic and fair algorithm for selecting router node.
 */

u32 tipc_node_select_router(struct node *n_ptr, u32 ref)
{
	u32 ulim;
	u32 mask;
	u32 start;
	u32 r;

	if (!n_ptr)
		return 0;

	if (n_ptr->last_router < 0)
		return 0;
	ulim = ((n_ptr->last_router + 1) * 32) - 1;

	/* Start entry must be random */
	mask = tipc_max_nodes;
	while (mask > ulim)
		mask >>= 1;
	start = ref & mask;
	r = start;

	/* Lookup upwards with wrap-around */
	do {
		if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
			break;
	} while (++r <= ulim);
	if (r > ulim) {
		r = 1;
		do {
			if (((n_ptr->routers[r / 32]) >> (r % 32)) & 1)
				break;
		} while (++r < start);
		assert(r != start);
	}
	assert(r && (r <= ulim));
	return tipc_addr(own_zone(), own_cluster(), r);
}

void tipc_node_add_router(struct node *n_ptr, u32 router)
{
	u32 r_num = tipc_node(router);

	n_ptr->routers[r_num / 32] =
		((1 << (r_num % 32)) | n_ptr->routers[r_num / 32]);
	n_ptr->last_router = tipc_max_nodes / 32;
	while ((--n_ptr->last_router >= 0) &&
	       !n_ptr->routers[n_ptr->last_router]);
}

void tipc_node_remove_router(struct node *n_ptr, u32 router)
{
	u32 r_num = tipc_node(router);

	if (n_ptr->last_router < 0)
		return;		/* No routes */

	n_ptr->routers[r_num / 32] =
		((~(1 << (r_num % 32))) & (n_ptr->routers[r_num / 32]));
	n_ptr->last_router = tipc_max_nodes / 32;
	while ((--n_ptr->last_router >= 0) &&
	       !n_ptr->routers[n_ptr->last_router]);

	if (!tipc_node_is_up(n_ptr))
		node_lost_contact(n_ptr);
}

#if 0
void node_print(struct print_buf *buf, struct node *n_ptr, char *str)
{
	u32 i;

	tipc_printf(buf, "\n\n%s", str);
	for (i = 0; i < MAX_BEARERS; i++) {
		if (!n_ptr->links[i])
			continue;
		tipc_printf(buf, "Links[%u]: %x, ", i, n_ptr->links[i]);
	}
	tipc_printf(buf, "Active links: [%x,%x]\n",
		    n_ptr->active_links[0], n_ptr->active_links[1]);
}
#endif

u32 tipc_available_nodes(const u32 domain)
{
	struct node *n_ptr;
	u32 cnt = 0;

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		if (!in_scope(domain, n_ptr->addr))
			continue;
		if (tipc_node_is_up(n_ptr))
			cnt++;
	}
	return cnt;
}

struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space)
{
	u32 domain;
	struct sk_buff *buf;
	struct node *n_ptr;
	struct tipc_node_info node_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
						   " (network address)");

	if (!tipc_nodes)
		return tipc_cfg_reply_none();

	/* For now, get space for all other nodes
	   (will need to modify this when slave nodes are supported */

	payload_size = TLV_SPACE(sizeof(node_info)) * (tipc_max_nodes - 1);
	if (payload_size > 32768u)
		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
						   " (too many nodes)");
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf)
		return NULL;

	/* Add TLVs for all nodes in scope */

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		if (!in_scope(domain, n_ptr->addr))
			continue;
		node_info.addr = htonl(n_ptr->addr);
		node_info.up = htonl(tipc_node_is_up(n_ptr));
		tipc_cfg_append_tlv(buf, TIPC_TLV_NODE_INFO,
				    &node_info, sizeof(node_info));
	}

	return buf;
}

struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space)
{
	u32 domain;
	struct sk_buff *buf;
	struct node *n_ptr;
	struct tipc_link_info link_info;
	u32 payload_size;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NET_ADDR))
		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	domain = ntohl(*(__be32 *)TLV_DATA(req_tlv_area));
	if (!tipc_addr_domain_valid(domain))
		return tipc_cfg_reply_error_string(TIPC_CFG_INVALID_VALUE
						   " (network address)");

	if (tipc_mode != TIPC_NET_MODE)
		return tipc_cfg_reply_none();

	/* Get space for all unicast links + multicast link */

	payload_size = TLV_SPACE(sizeof(link_info)) *
		(tipc_net.zones[tipc_zone(tipc_own_addr)]->links + 1);
	if (payload_size > 32768u)
		return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
						   " (too many links)");
	buf = tipc_cfg_reply_alloc(payload_size);
	if (!buf)
		return NULL;

	/* Add TLV for broadcast link */

	link_info.dest = htonl(tipc_own_addr & 0xfffff00);
	link_info.up = htonl(1);
	sprintf(link_info.str, tipc_bclink_name);
	tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO, &link_info, sizeof(link_info));

	/* Add TLVs for any other links in scope */

	for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
		u32 i;

		if (!in_scope(domain, n_ptr->addr))
			continue;
		for (i = 0; i < MAX_BEARERS; i++) {
			if (!n_ptr->links[i])
				continue;
			link_info.dest = htonl(n_ptr->addr);
			link_info.up = htonl(tipc_link_is_up(n_ptr->links[i]));
			strcpy(link_info.str, n_ptr->links[i]->name);
			tipc_cfg_append_tlv(buf, TIPC_TLV_LINK_INFO,
					    &link_info, sizeof(link_info));
		}
	}

	return buf;
}