node.c

linux 内核源代码

/*
 * net/tipc/node.c: TIPC node management routines
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2005-2006, Wind River Systems
 * 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. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

#include "core.h"
#include "config.h"
#include "node.h"
#include "cluster.h"
#include "net.h"
#include "addr.h"
#include "node_subscr.h"
#include "link.h"
#include "port.h"
#include "bearer.h"
#include "name_distr.h"

void node_print(struct print_buf *buf, struct node *n_ptr, char *str);
static void node_lost_contact(struct node *n_ptr);
static void node_established_contact(struct node *n_ptr);

struct node *tipc_nodes = NULL;	/* sorted list of nodes within cluster */

u32 tipc_own_tag = 0;

struct node *tipc_node_create(u32 addr)
{
	struct cluster *c_ptr;
	struct node *n_ptr;
	struct node **curr_node;

	n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
	if (!n_ptr) {
		warn("Node creation failed, no memory\n");
		return NULL;
	}

	c_ptr = tipc_cltr_find(addr);
	if (!c_ptr) {
		c_ptr = tipc_cltr_create(addr);
	}
	if (!c_ptr) {
		kfree(n_ptr);
		return NULL;
	}

	n_ptr->addr = addr;
		spin_lock_init(&n_ptr->lock);
	INIT_LIST_HEAD(&n_ptr->nsub);
	n_ptr->owner = c_ptr;
	tipc_cltr_attach_node(c_ptr, n_ptr);
	n_ptr->last_router = -1;

	/* Insert node into ordered list */
	for (curr_node = &tipc_nodes; *curr_node;
	     curr_node = &(*curr_node)->next) {
		if (addr < (*curr_node)->addr) {
			n_ptr->next = *curr_node;
			break;
		}
	}
	(*curr_node) = n_ptr;
	return n_ptr;
}

void tipc_node_delete(struct node *n_ptr)
{
	if (!n_ptr)
		return;

#if 0
	/* Not needed because links are already deleted via tipc_bearer_stop() */

	u32 l_num;

	for (l_num = 0; l_num < MAX_BEARERS; l_num++) {
		link_delete(n_ptr->links[l_num]);
	}
#endif

	dbg("node %x deleted\n", n_ptr->addr);
	kfree(n_ptr);
}


/**
 * tipc_node_link_up - handle addition of link
 *
 * Link becomes active (alone or shared) or standby, depending on its priority.
 */

void tipc_node_link_up(struct node *n_ptr, struct link *l_ptr)
{
	struct link **active = &n_ptr->active_links[0];

	n_ptr->working_links++;

	info("Established link <%s> on network plane %c\n",
	     l_ptr->name, l_ptr->b_ptr->net_plane);

	if (!active[0]) {
		dbg(" link %x into %x/%x\n", l_ptr, &active[0], &active[1]);
		active[0] = active[1] = l_ptr;
		node_established_contact(n_ptr);
		return;
	}
	if (l_ptr->priority < active[0]->priority) {
		info("New link <%s> becomes standby\n", l_ptr->name);
		return;
	}
	tipc_link_send_duplicate(active[0], l_ptr);
	if (l_ptr->priority == active[0]->priority) {
		active[0] = l_ptr;
		return;
	}
	info("Old link <%s> becomes standby\n", active[0]->name);
	if (active[1] != active[0])
		info("Old link <%s> becomes standby\n", active[1]->name);
	active[0] = active[1] = l_ptr;
}

/**
 * node_select_active_links - select active link
 */

static void node_select_active_links(struct node *n_ptr)
{
	struct link **active = &n_ptr->active_links[0];
	u32 i;
	u32 highest_prio = 0;

	active[0] = active[1] = NULL;

	for (i = 0; i < MAX_BEARERS; i++) {
		struct link *l_ptr = n_ptr->links[i];

		if (!l_ptr || !tipc_link_is_up(l_ptr) ||
		    (l_ptr->priority < highest_prio))
			continue;

		if (l_ptr->priority > highest_prio) {
			highest_prio = l_ptr->priority;
			active[0] = active[1] = l_ptr;
		} else {
			active[1] = l_ptr;
		}
	}
}

/**
 * tipc_node_link_down - handle loss of link
 */

void tipc_node_link_down(struct node *n_ptr, struct link *l_ptr)
{
	struct link **active;

	n_ptr->working_links--;

	if (!tipc_link_is_active(l_ptr)) {
		info("Lost standby link <%s> on network plane %c\n",
		     l_ptr->name, l_ptr->b_ptr->net_plane);
		return;
	}
	info("Lost link <%s> on network plane %c\n",
		l_ptr->name, l_ptr->b_ptr->net_plane);

	active = &n_ptr->active_links[0];
	if (active[0] == l_ptr)
		active[0] = active[1];
	if (active[1] == l_ptr)
		active[1] = active[0];
	if (active[0] == l_ptr)
		node_select_active_links(n_ptr);
	if (tipc_node_is_up(n_ptr))
		tipc_link_changeover(l_ptr);
	else
		node_lost_contact(n_ptr);
}

int tipc_node_has_active_links(struct node *n_ptr)
{
	return (n_ptr &&
		((n_ptr->active_links[0]) || (n_ptr->active_links[1])));
}

int tipc_node_has_redundant_links(struct node *n_ptr)
{
	return (n_ptr->working_links > 1);
}

static int tipc_node_has_active_routes(struct node *n_ptr)
{
	return (n_ptr && (n_ptr->last_router >= 0));
}

int tipc_node_is_up(struct node *n_ptr)
{
	return (tipc_node_has_active_links(n_ptr) || tipc_node_has_active_routes(n_ptr));
}

struct node *tipc_node_attach_link(struct link *l_ptr)
{
	struct node *n_ptr = tipc_node_find(l_ptr->addr);

	if (!n_ptr)
		n_ptr = tipc_node_create(l_ptr->addr);
	if (n_ptr) {
		u32 bearer_id = l_ptr->b_ptr->identity;
		char addr_string[16];

		if (n_ptr->link_cnt >= 2) {
			err("Attempt to create third link to %s\n",
			    addr_string_fill(addr_string, n_ptr->addr));
			return NULL;
		}

		if (!n_ptr->links[bearer_id]) {
			n_ptr->links[bearer_id] = l_ptr;
			tipc_net.zones[tipc_zone(l_ptr->addr)]->links++;
			n_ptr->link_cnt++;
			return n_ptr;
		}
		err("Attempt to establish second link on <%s> to %s \n",
		    l_ptr->b_ptr->publ.name,
		    addr_string_fill(addr_string, l_ptr->addr));
	}
	return NULL;
}

void tipc_node_detach_link(struct node *n_ptr, struct link *l_ptr)
{
	n_ptr->links[l_ptr->b_ptr->identity] = NULL;
	tipc_net.zones[tipc_zone(l_ptr->addr)]->links--;
	n_ptr->link_cnt--;
}

/*
 * Routing table management - five cases to handle:
 *
 * 1: A link towards a zone/cluster external node comes up.
 *    => Send a multicast message updating routing tables of all
 *    system nodes within own cluster that the new destination
 *    can be reached via this node.
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *
 * 2: A link towards a slave node comes up.
 *    => Send a multicast message updating routing tables of all
 *    system nodes within own cluster that the new destination
 *    can be reached via this node.
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *    => Send a  message to the slave node about existence
 *    of all system nodes within cluster:
 *    (node.establishedContact()=>cluster.sendLocalRoutes())
 *
 * 3: A new cluster local system node becomes available.
 *    => Send message(s) to this particular node containing
 *    information about all cluster external and slave
 *     nodes which can be reached via this node.
 *    (node.establishedContact()==>network.sendExternalRoutes())
 *    (node.establishedContact()==>network.sendSlaveRoutes())
 *    => Send messages to all directly connected slave nodes
 *    containing information about the existence of the new node
 *    (node.establishedContact()=>cluster.multicastNewRoute())
 *
 * 4: The link towards a zone/cluster external node or slave
 *    node goes down.
 *    => Send a multcast message updating routing tables of all
 *    nodes within cluster that the new destination can not any
 *    longer be reached via this node.
 *    (node.lostAllLinks()=>cluster.bcastLostRoute())
 *
 * 5: A cluster local system node becomes unavailable.
 *    => Remove all references to this node from the local
 *    routing tables. Note: This is a completely node
 *    local operation.
 *    (node.lostAllLinks()=>network.removeAsRouter())
 *    => Send messages to all directly connected slave nodes
 *    containing information about loss of the node
 *    (node.establishedContact()=>cluster.multicastLostRoute())
 *
 */

static void node_established_contact(struct node *n_ptr)
{
	struct cluster *c_ptr;

	dbg("node_established_contact:-> %x\n", n_ptr->addr);
	if (!tipc_node_has_active_routes(n_ptr) && in_own_cluster(n_ptr->addr)) {
		tipc_k_signal((Handler)tipc_named_node_up, n_ptr->addr);
	}

	/* Syncronize broadcast acks */
	n_ptr->bclink.acked = tipc_bclink_get_last_sent();

	if (is_slave(tipc_own_addr))
		return;
	if (!in_own_cluster(n_ptr->addr)) {
		/* Usage case 1 (see above) */
		c_ptr = tipc_cltr_find(tipc_own_addr);
		if (!c_ptr)
			c_ptr = tipc_cltr_create(tipc_own_addr);
		if (c_ptr)
			tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1,
						  tipc_max_nodes);
		return;
	}

	c_ptr = n_ptr->owner;
	if (is_slave(n_ptr->addr)) {
		/* Usage case 2 (see above) */
		tipc_cltr_bcast_new_route(c_ptr, n_ptr->addr, 1, tipc_max_nodes);
		tipc_cltr_send_local_routes(c_ptr, n_ptr->addr);