linux/net/tipc/node.c
Allan Stephens 5a68d5ee00 tipc: Prevent missing name table entries when link flip-flops rapidly
Ensure that TIPC does not re-establish communication with a
neighboring node until it has finished updating all data structures
containing information about that node to reflect the earlier loss of
contact.  Previously, it was possible for TIPC to perform its purge of
name table entries relating to the node once contact had already been
re-established, resulting in the unwanted removal of valid name table
entries.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-17 17:32:00 -07:00

750 lines
20 KiB
C

/*
* 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 tipc_node *n_ptr, char *str);
static void node_lost_contact(struct tipc_node *n_ptr);
static void node_established_contact(struct tipc_node *n_ptr);
struct tipc_node *tipc_nodes = NULL; /* sorted list of nodes within cluster */
static DEFINE_SPINLOCK(node_create_lock);
u32 tipc_own_tag = 0;
/**
* tipc_node_create - create neighboring node
*
* Currently, this routine is called by neighbor discovery code, which holds
* net_lock for reading only. We must take node_create_lock to ensure a node
* isn't created twice if two different bearers discover the node at the same
* time. (It would be preferable to switch to holding net_lock in write mode,
* but this is a non-trivial change.)
*/
struct tipc_node *tipc_node_create(u32 addr)
{
struct cluster *c_ptr;
struct tipc_node *n_ptr;
struct tipc_node **curr_node;
spin_lock_bh(&node_create_lock);
for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
if (addr < n_ptr->addr)
break;
if (addr == n_ptr->addr) {
spin_unlock_bh(&node_create_lock);
return n_ptr;
}
}
n_ptr = kzalloc(sizeof(*n_ptr),GFP_ATOMIC);
if (!n_ptr) {
spin_unlock_bh(&node_create_lock);
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) {
spin_unlock_bh(&node_create_lock);
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;
spin_unlock_bh(&node_create_lock);
return n_ptr;
}
void tipc_node_delete(struct tipc_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 tipc_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 tipc_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 tipc_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 tipc_node *n_ptr)
{
return n_ptr->active_links[0] != NULL;
}
int tipc_node_has_redundant_links(struct tipc_node *n_ptr)
{
return (n_ptr->working_links > 1);
}
static int tipc_node_has_active_routes(struct tipc_node *n_ptr)
{
return (n_ptr && (n_ptr->last_router >= 0));
}
int tipc_node_is_up(struct tipc_node *n_ptr)
{
return (tipc_node_has_active_links(n_ptr) || tipc_node_has_active_routes(n_ptr));
}
struct tipc_node *tipc_node_attach_link(struct link *l_ptr)
{
struct tipc_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",
tipc_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,
tipc_addr_string_fill(addr_string, l_ptr->addr));
}
return NULL;
}
void tipc_node_detach_link(struct tipc_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 tipc_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);
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_cleanup_finished(unsigned long node_addr)
{
struct tipc_node *n_ptr;
read_lock_bh(&tipc_net_lock);
n_ptr = tipc_node_find(node_addr);
if (n_ptr) {
tipc_node_lock(n_ptr);
n_ptr->cleanup_required = 0;
tipc_node_unlock(n_ptr);
}
read_unlock_bh(&tipc_net_lock);
}
static void node_lost_contact(struct tipc_node *n_ptr)
{
struct cluster *c_ptr;
struct tipc_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",
tipc_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);
}
/* Prevent re-contact with node until all cleanup is done */
n_ptr->cleanup_required = 1;
tipc_k_signal((Handler)node_cleanup_finished, n_ptr->addr);
}
/**
* tipc_node_select_next_hop - find the next-hop node for a message
*
* Called by when cluster local lookup has failed.
*/
struct tipc_node *tipc_node_select_next_hop(u32 addr, u32 selector)
{
struct tipc_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 tipc_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 tipc_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 tipc_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 tipc_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 tipc_node *n_ptr;
u32 cnt = 0;
read_lock_bh(&tipc_net_lock);
for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
if (!tipc_in_scope(domain, n_ptr->addr))
continue;
if (tipc_node_is_up(n_ptr))
cnt++;
}
read_unlock_bh(&tipc_net_lock);
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 tipc_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)");
read_lock_bh(&tipc_net_lock);
if (!tipc_nodes) {
read_unlock_bh(&tipc_net_lock);
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) {
read_unlock_bh(&tipc_net_lock);
return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
" (too many nodes)");
}
buf = tipc_cfg_reply_alloc(payload_size);
if (!buf) {
read_unlock_bh(&tipc_net_lock);
return NULL;
}
/* Add TLVs for all nodes in scope */
for (n_ptr = tipc_nodes; n_ptr; n_ptr = n_ptr->next) {
if (!tipc_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));
}
read_unlock_bh(&tipc_net_lock);
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 tipc_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();
read_lock_bh(&tipc_net_lock);
/* 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) {
read_unlock_bh(&tipc_net_lock);
return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
" (too many links)");
}
buf = tipc_cfg_reply_alloc(payload_size);
if (!buf) {
read_unlock_bh(&tipc_net_lock);
return NULL;
}
/* Add TLV for broadcast link */
link_info.dest = htonl(tipc_own_addr & 0xfffff00);
link_info.up = htonl(1);
strlcpy(link_info.str, tipc_bclink_name, TIPC_MAX_LINK_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 (!tipc_in_scope(domain, n_ptr->addr))
continue;
tipc_node_lock(n_ptr);
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));
}
tipc_node_unlock(n_ptr);
}
read_unlock_bh(&tipc_net_lock);
return buf;
}