linux/net/tipc/monitor.c
Jon Maloy fa36882682 tipc: eliminate unnecessary probing
The neighbor monitor employs a threshold, default set to 32 peer nodes,
where it activates the "Overlapping Neighbor Monitoring" algorithm.
Below that threshold, monitoring is full-mesh, and no "domain records"
are passed between the nodes.

Because of this, a node never received a peer's ack that it has received
the most recent update of the own domain. Hence, the field 'acked_gen'
in struct tipc_monitor_state remains permamently at zero, whereas the
own domain generation is incremented for each added or removed peer.

This has the effect that the function tipc_mon_get_state() always sets
the field 'probing' in struct tipc_monitor_state true, again leading the
tipc_link_timeout() of the link in question to always send out a probe,
even when link->silent_intv_count is zero.

This is functionally harmless, but leads to some unncessary probing,
which can easily be eliminated by setting the 'probing' field of the
said struct correctly in such cases.

At the same time, we explictly invalidate the sent domain records when
the algorithm is not activated. This will eliminate any risk that an
invalid domain record might be inadverently accepted by the peer.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03 15:48:46 +09:00

814 lines
21 KiB
C

/*
* net/tipc/monitor.c
*
* Copyright (c) 2016, Ericsson AB
* 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 <net/genetlink.h>
#include "core.h"
#include "addr.h"
#include "monitor.h"
#include "bearer.h"
#define MAX_MON_DOMAIN 64
#define MON_TIMEOUT 120000
#define MAX_PEER_DOWN_EVENTS 4
/* struct tipc_mon_domain: domain record to be transferred between peers
* @len: actual size of domain record
* @gen: current generation of sender's domain
* @ack_gen: most recent generation of self's domain acked by peer
* @member_cnt: number of domain member nodes described in this record
* @up_map: bit map indicating which of the members the sender considers up
* @members: identity of the domain members
*/
struct tipc_mon_domain {
u16 len;
u16 gen;
u16 ack_gen;
u16 member_cnt;
u64 up_map;
u32 members[MAX_MON_DOMAIN];
};
/* struct tipc_peer: state of a peer node and its domain
* @addr: tipc node identity of peer
* @head_map: shows which other nodes currently consider peer 'up'
* @domain: most recent domain record from peer
* @hash: position in hashed lookup list
* @list: position in linked list, in circular ascending order by 'addr'
* @applied: number of reported domain members applied on this monitor list
* @is_up: peer is up as seen from this node
* @is_head: peer is assigned domain head as seen from this node
* @is_local: peer is in local domain and should be continuously monitored
* @down_cnt: - numbers of other peers which have reported this on lost
*/
struct tipc_peer {
u32 addr;
struct tipc_mon_domain *domain;
struct hlist_node hash;
struct list_head list;
u8 applied;
u8 down_cnt;
bool is_up;
bool is_head;
bool is_local;
};
struct tipc_monitor {
struct hlist_head peers[NODE_HTABLE_SIZE];
int peer_cnt;
struct tipc_peer *self;
rwlock_t lock;
struct tipc_mon_domain cache;
u16 list_gen;
u16 dom_gen;
struct net *net;
struct timer_list timer;
unsigned long timer_intv;
};
static struct tipc_monitor *tipc_monitor(struct net *net, int bearer_id)
{
return tipc_net(net)->monitors[bearer_id];
}
const int tipc_max_domain_size = sizeof(struct tipc_mon_domain);
/* dom_rec_len(): actual length of domain record for transport
*/
static int dom_rec_len(struct tipc_mon_domain *dom, u16 mcnt)
{
return ((void *)&dom->members - (void *)dom) + (mcnt * sizeof(u32));
}
/* dom_size() : calculate size of own domain based on number of peers
*/
static int dom_size(int peers)
{
int i = 0;
while ((i * i) < peers)
i++;
return i < MAX_MON_DOMAIN ? i : MAX_MON_DOMAIN;
}
static void map_set(u64 *up_map, int i, unsigned int v)
{
*up_map &= ~(1ULL << i);
*up_map |= ((u64)v << i);
}
static int map_get(u64 up_map, int i)
{
return (up_map & (1 << i)) >> i;
}
static struct tipc_peer *peer_prev(struct tipc_peer *peer)
{
return list_last_entry(&peer->list, struct tipc_peer, list);
}
static struct tipc_peer *peer_nxt(struct tipc_peer *peer)
{
return list_first_entry(&peer->list, struct tipc_peer, list);
}
static struct tipc_peer *peer_head(struct tipc_peer *peer)
{
while (!peer->is_head)
peer = peer_prev(peer);
return peer;
}
static struct tipc_peer *get_peer(struct tipc_monitor *mon, u32 addr)
{
struct tipc_peer *peer;
unsigned int thash = tipc_hashfn(addr);
hlist_for_each_entry(peer, &mon->peers[thash], hash) {
if (peer->addr == addr)
return peer;
}
return NULL;
}
static struct tipc_peer *get_self(struct net *net, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
return mon->self;
}
static inline bool tipc_mon_is_active(struct net *net, struct tipc_monitor *mon)
{
struct tipc_net *tn = tipc_net(net);
return mon->peer_cnt > tn->mon_threshold;
}
/* mon_identify_lost_members() : - identify amd mark potentially lost members
*/
static void mon_identify_lost_members(struct tipc_peer *peer,
struct tipc_mon_domain *dom_bef,
int applied_bef)
{
struct tipc_peer *member = peer;
struct tipc_mon_domain *dom_aft = peer->domain;
int applied_aft = peer->applied;
int i;
for (i = 0; i < applied_bef; i++) {
member = peer_nxt(member);
/* Do nothing if self or peer already see member as down */
if (!member->is_up || !map_get(dom_bef->up_map, i))
continue;
/* Loss of local node must be detected by active probing */
if (member->is_local)
continue;
/* Start probing if member was removed from applied domain */
if (!applied_aft || (applied_aft < i)) {
member->down_cnt = 1;
continue;
}
/* Member loss is confirmed if it is still in applied domain */
if (!map_get(dom_aft->up_map, i))
member->down_cnt++;
}
}
/* mon_apply_domain() : match a peer's domain record against monitor list
*/
static void mon_apply_domain(struct tipc_monitor *mon,
struct tipc_peer *peer)
{
struct tipc_mon_domain *dom = peer->domain;
struct tipc_peer *member;
u32 addr;
int i;
if (!dom || !peer->is_up)
return;
/* Scan across domain members and match against monitor list */
peer->applied = 0;
member = peer_nxt(peer);
for (i = 0; i < dom->member_cnt; i++) {
addr = dom->members[i];
if (addr != member->addr)
return;
peer->applied++;
member = peer_nxt(member);
}
}
/* mon_update_local_domain() : update after peer addition/removal/up/down
*/
static void mon_update_local_domain(struct tipc_monitor *mon)
{
struct tipc_peer *self = mon->self;
struct tipc_mon_domain *cache = &mon->cache;
struct tipc_mon_domain *dom = self->domain;
struct tipc_peer *peer = self;
u64 prev_up_map = dom->up_map;
u16 member_cnt, i;
bool diff;
/* Update local domain size based on current size of cluster */
member_cnt = dom_size(mon->peer_cnt) - 1;
self->applied = member_cnt;
/* Update native and cached outgoing local domain records */
dom->len = dom_rec_len(dom, member_cnt);
diff = dom->member_cnt != member_cnt;
dom->member_cnt = member_cnt;
for (i = 0; i < member_cnt; i++) {
peer = peer_nxt(peer);
diff |= dom->members[i] != peer->addr;
dom->members[i] = peer->addr;
map_set(&dom->up_map, i, peer->is_up);
cache->members[i] = htonl(peer->addr);
}
diff |= dom->up_map != prev_up_map;
if (!diff)
return;
dom->gen = ++mon->dom_gen;
cache->len = htons(dom->len);
cache->gen = htons(dom->gen);
cache->member_cnt = htons(member_cnt);
cache->up_map = cpu_to_be64(dom->up_map);
mon_apply_domain(mon, self);
}
/* mon_update_neighbors() : update preceding neighbors of added/removed peer
*/
static void mon_update_neighbors(struct tipc_monitor *mon,
struct tipc_peer *peer)
{
int dz, i;
dz = dom_size(mon->peer_cnt);
for (i = 0; i < dz; i++) {
mon_apply_domain(mon, peer);
peer = peer_prev(peer);
}
}
/* mon_assign_roles() : reassign peer roles after a network change
* The monitor list is consistent at this stage; i.e., each peer is monitoring
* a set of domain members as matched between domain record and the monitor list
*/
static void mon_assign_roles(struct tipc_monitor *mon, struct tipc_peer *head)
{
struct tipc_peer *peer = peer_nxt(head);
struct tipc_peer *self = mon->self;
int i = 0;
for (; peer != self; peer = peer_nxt(peer)) {
peer->is_local = false;
/* Update domain member */
if (i++ < head->applied) {
peer->is_head = false;
if (head == self)
peer->is_local = true;
continue;
}
/* Assign next domain head */
if (!peer->is_up)
continue;
if (peer->is_head)
break;
head = peer;
head->is_head = true;
i = 0;
}
mon->list_gen++;
}
void tipc_mon_remove_peer(struct net *net, u32 addr, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *self = get_self(net, bearer_id);
struct tipc_peer *peer, *prev, *head;
write_lock_bh(&mon->lock);
peer = get_peer(mon, addr);
if (!peer)
goto exit;
prev = peer_prev(peer);
list_del(&peer->list);
hlist_del(&peer->hash);
kfree(peer->domain);
kfree(peer);
mon->peer_cnt--;
head = peer_head(prev);
if (head == self)
mon_update_local_domain(mon);
mon_update_neighbors(mon, prev);
/* Revert to full-mesh monitoring if we reach threshold */
if (!tipc_mon_is_active(net, mon)) {
list_for_each_entry(peer, &self->list, list) {
kfree(peer->domain);
peer->domain = NULL;
peer->applied = 0;
}
}
mon_assign_roles(mon, head);
exit:
write_unlock_bh(&mon->lock);
}
static bool tipc_mon_add_peer(struct tipc_monitor *mon, u32 addr,
struct tipc_peer **peer)
{
struct tipc_peer *self = mon->self;
struct tipc_peer *cur, *prev, *p;
p = kzalloc(sizeof(*p), GFP_ATOMIC);
*peer = p;
if (!p)
return false;
p->addr = addr;
/* Add new peer to lookup list */
INIT_LIST_HEAD(&p->list);
hlist_add_head(&p->hash, &mon->peers[tipc_hashfn(addr)]);
/* Sort new peer into iterator list, in ascending circular order */
prev = self;
list_for_each_entry(cur, &self->list, list) {
if ((addr > prev->addr) && (addr < cur->addr))
break;
if (((addr < cur->addr) || (addr > prev->addr)) &&
(prev->addr > cur->addr))
break;
prev = cur;
}
list_add_tail(&p->list, &cur->list);
mon->peer_cnt++;
mon_update_neighbors(mon, p);
return true;
}
void tipc_mon_peer_up(struct net *net, u32 addr, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *self = get_self(net, bearer_id);
struct tipc_peer *peer, *head;
write_lock_bh(&mon->lock);
peer = get_peer(mon, addr);
if (!peer && !tipc_mon_add_peer(mon, addr, &peer))
goto exit;
peer->is_up = true;
head = peer_head(peer);
if (head == self)
mon_update_local_domain(mon);
mon_assign_roles(mon, head);
exit:
write_unlock_bh(&mon->lock);
}
void tipc_mon_peer_down(struct net *net, u32 addr, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *self = get_self(net, bearer_id);
struct tipc_peer *peer, *head;
struct tipc_mon_domain *dom;
int applied;
write_lock_bh(&mon->lock);
peer = get_peer(mon, addr);
if (!peer) {
pr_warn("Mon: unknown link %x/%u DOWN\n", addr, bearer_id);
goto exit;
}
applied = peer->applied;
peer->applied = 0;
dom = peer->domain;
peer->domain = NULL;
if (peer->is_head)
mon_identify_lost_members(peer, dom, applied);
kfree(dom);
peer->is_up = false;
peer->is_head = false;
peer->is_local = false;
peer->down_cnt = 0;
head = peer_head(peer);
if (head == self)
mon_update_local_domain(mon);
mon_assign_roles(mon, head);
exit:
write_unlock_bh(&mon->lock);
}
/* tipc_mon_rcv - process monitor domain event message
*/
void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
struct tipc_mon_state *state, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_mon_domain *arrv_dom = data;
struct tipc_mon_domain dom_bef;
struct tipc_mon_domain *dom;
struct tipc_peer *peer;
u16 new_member_cnt = ntohs(arrv_dom->member_cnt);
int new_dlen = dom_rec_len(arrv_dom, new_member_cnt);
u16 new_gen = ntohs(arrv_dom->gen);
u16 acked_gen = ntohs(arrv_dom->ack_gen);
bool probing = state->probing;
int i, applied_bef;
state->probing = false;
/* Sanity check received domain record */
if (dlen < dom_rec_len(arrv_dom, 0))
return;
if (dlen != dom_rec_len(arrv_dom, new_member_cnt))
return;
if ((dlen < new_dlen) || ntohs(arrv_dom->len) != new_dlen)
return;
/* Synch generation numbers with peer if link just came up */
if (!state->synched) {
state->peer_gen = new_gen - 1;
state->acked_gen = acked_gen;
state->synched = true;
}
if (more(acked_gen, state->acked_gen))
state->acked_gen = acked_gen;
/* Drop duplicate unless we are waiting for a probe response */
if (!more(new_gen, state->peer_gen) && !probing)
return;
write_lock_bh(&mon->lock);
peer = get_peer(mon, addr);
if (!peer || !peer->is_up)
goto exit;
/* Peer is confirmed, stop any ongoing probing */
peer->down_cnt = 0;
/* Task is done for duplicate record */
if (!more(new_gen, state->peer_gen))
goto exit;
state->peer_gen = new_gen;
/* Cache current domain record for later use */
dom_bef.member_cnt = 0;
dom = peer->domain;
if (dom)
memcpy(&dom_bef, dom, dom->len);
/* Transform and store received domain record */
if (!dom || (dom->len < new_dlen)) {
kfree(dom);
dom = kmalloc(new_dlen, GFP_ATOMIC);
peer->domain = dom;
if (!dom)
goto exit;
}
dom->len = new_dlen;
dom->gen = new_gen;
dom->member_cnt = new_member_cnt;
dom->up_map = be64_to_cpu(arrv_dom->up_map);
for (i = 0; i < new_member_cnt; i++)
dom->members[i] = ntohl(arrv_dom->members[i]);
/* Update peers affected by this domain record */
applied_bef = peer->applied;
mon_apply_domain(mon, peer);
mon_identify_lost_members(peer, &dom_bef, applied_bef);
mon_assign_roles(mon, peer_head(peer));
exit:
write_unlock_bh(&mon->lock);
}
void tipc_mon_prep(struct net *net, void *data, int *dlen,
struct tipc_mon_state *state, int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_mon_domain *dom = data;
u16 gen = mon->dom_gen;
u16 len;
/* Send invalid record if not active */
if (!tipc_mon_is_active(net, mon)) {
dom->len = 0;
return;
}
/* Send only a dummy record with ack if peer has acked our last sent */
if (likely(state->acked_gen == gen)) {
len = dom_rec_len(dom, 0);
*dlen = len;
dom->len = htons(len);
dom->gen = htons(gen);
dom->ack_gen = htons(state->peer_gen);
dom->member_cnt = 0;
return;
}
/* Send the full record */
read_lock_bh(&mon->lock);
len = ntohs(mon->cache.len);
*dlen = len;
memcpy(data, &mon->cache, len);
read_unlock_bh(&mon->lock);
dom->ack_gen = htons(state->peer_gen);
}
void tipc_mon_get_state(struct net *net, u32 addr,
struct tipc_mon_state *state,
int bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *peer;
if (!tipc_mon_is_active(net, mon)) {
state->probing = false;
state->monitoring = true;
return;
}
/* Used cached state if table has not changed */
if (!state->probing &&
(state->list_gen == mon->list_gen) &&
(state->acked_gen == mon->dom_gen))
return;
read_lock_bh(&mon->lock);
peer = get_peer(mon, addr);
if (peer) {
state->probing = state->acked_gen != mon->dom_gen;
state->probing |= peer->down_cnt;
state->reset |= peer->down_cnt >= MAX_PEER_DOWN_EVENTS;
state->monitoring = peer->is_local;
state->monitoring |= peer->is_head;
state->list_gen = mon->list_gen;
}
read_unlock_bh(&mon->lock);
}
static void mon_timeout(struct timer_list *t)
{
struct tipc_monitor *mon = from_timer(mon, t, timer);
struct tipc_peer *self;
int best_member_cnt = dom_size(mon->peer_cnt) - 1;
write_lock_bh(&mon->lock);
self = mon->self;
if (self && (best_member_cnt != self->applied)) {
mon_update_local_domain(mon);
mon_assign_roles(mon, self);
}
write_unlock_bh(&mon->lock);
mod_timer(&mon->timer, jiffies + mon->timer_intv);
}
int tipc_mon_create(struct net *net, int bearer_id)
{
struct tipc_net *tn = tipc_net(net);
struct tipc_monitor *mon;
struct tipc_peer *self;
struct tipc_mon_domain *dom;
if (tn->monitors[bearer_id])
return 0;
mon = kzalloc(sizeof(*mon), GFP_ATOMIC);
self = kzalloc(sizeof(*self), GFP_ATOMIC);
dom = kzalloc(sizeof(*dom), GFP_ATOMIC);
if (!mon || !self || !dom) {
kfree(mon);
kfree(self);
kfree(dom);
return -ENOMEM;
}
tn->monitors[bearer_id] = mon;
rwlock_init(&mon->lock);
mon->net = net;
mon->peer_cnt = 1;
mon->self = self;
self->domain = dom;
self->addr = tipc_own_addr(net);
self->is_up = true;
self->is_head = true;
INIT_LIST_HEAD(&self->list);
timer_setup(&mon->timer, mon_timeout, 0);
mon->timer_intv = msecs_to_jiffies(MON_TIMEOUT + (tn->random & 0xffff));
mod_timer(&mon->timer, jiffies + mon->timer_intv);
return 0;
}
void tipc_mon_delete(struct net *net, int bearer_id)
{
struct tipc_net *tn = tipc_net(net);
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *self = get_self(net, bearer_id);
struct tipc_peer *peer, *tmp;
write_lock_bh(&mon->lock);
tn->monitors[bearer_id] = NULL;
list_for_each_entry_safe(peer, tmp, &self->list, list) {
list_del(&peer->list);
hlist_del(&peer->hash);
kfree(peer->domain);
kfree(peer);
}
mon->self = NULL;
write_unlock_bh(&mon->lock);
del_timer_sync(&mon->timer);
kfree(self->domain);
kfree(self);
kfree(mon);
}
int tipc_nl_monitor_set_threshold(struct net *net, u32 cluster_size)
{
struct tipc_net *tn = tipc_net(net);
if (cluster_size > TIPC_CLUSTER_SIZE)
return -EINVAL;
tn->mon_threshold = cluster_size;
return 0;
}
int tipc_nl_monitor_get_threshold(struct net *net)
{
struct tipc_net *tn = tipc_net(net);
return tn->mon_threshold;
}
int __tipc_nl_add_monitor_peer(struct tipc_peer *peer, struct tipc_nl_msg *msg)
{
struct tipc_mon_domain *dom = peer->domain;
struct nlattr *attrs;
void *hdr;
hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
NLM_F_MULTI, TIPC_NL_MON_PEER_GET);
if (!hdr)
return -EMSGSIZE;
attrs = nla_nest_start(msg->skb, TIPC_NLA_MON_PEER);
if (!attrs)
goto msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_MON_PEER_ADDR, peer->addr))
goto attr_msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_MON_PEER_APPLIED, peer->applied))
goto attr_msg_full;
if (peer->is_up)
if (nla_put_flag(msg->skb, TIPC_NLA_MON_PEER_UP))
goto attr_msg_full;
if (peer->is_local)
if (nla_put_flag(msg->skb, TIPC_NLA_MON_PEER_LOCAL))
goto attr_msg_full;
if (peer->is_head)
if (nla_put_flag(msg->skb, TIPC_NLA_MON_PEER_HEAD))
goto attr_msg_full;
if (dom) {
if (nla_put_u32(msg->skb, TIPC_NLA_MON_PEER_DOMGEN, dom->gen))
goto attr_msg_full;
if (nla_put_u64_64bit(msg->skb, TIPC_NLA_MON_PEER_UPMAP,
dom->up_map, TIPC_NLA_MON_PEER_PAD))
goto attr_msg_full;
if (nla_put(msg->skb, TIPC_NLA_MON_PEER_MEMBERS,
dom->member_cnt * sizeof(u32), &dom->members))
goto attr_msg_full;
}
nla_nest_end(msg->skb, attrs);
genlmsg_end(msg->skb, hdr);
return 0;
attr_msg_full:
nla_nest_cancel(msg->skb, attrs);
msg_full:
genlmsg_cancel(msg->skb, hdr);
return -EMSGSIZE;
}
int tipc_nl_add_monitor_peer(struct net *net, struct tipc_nl_msg *msg,
u32 bearer_id, u32 *prev_node)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
struct tipc_peer *peer;
if (!mon)
return -EINVAL;
read_lock_bh(&mon->lock);
peer = mon->self;
do {
if (*prev_node) {
if (peer->addr == *prev_node)
*prev_node = 0;
else
continue;
}
if (__tipc_nl_add_monitor_peer(peer, msg)) {
*prev_node = peer->addr;
read_unlock_bh(&mon->lock);
return -EMSGSIZE;
}
} while ((peer = peer_nxt(peer)) != mon->self);
read_unlock_bh(&mon->lock);
return 0;
}
int __tipc_nl_add_monitor(struct net *net, struct tipc_nl_msg *msg,
u32 bearer_id)
{
struct tipc_monitor *mon = tipc_monitor(net, bearer_id);
char bearer_name[TIPC_MAX_BEARER_NAME];
struct nlattr *attrs;
void *hdr;
int ret;
ret = tipc_bearer_get_name(net, bearer_name, bearer_id);
if (ret || !mon)
return -EINVAL;
hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
NLM_F_MULTI, TIPC_NL_MON_GET);
if (!hdr)
return -EMSGSIZE;
attrs = nla_nest_start(msg->skb, TIPC_NLA_MON);
if (!attrs)
goto msg_full;
read_lock_bh(&mon->lock);
if (nla_put_u32(msg->skb, TIPC_NLA_MON_REF, bearer_id))
goto attr_msg_full;
if (tipc_mon_is_active(net, mon))
if (nla_put_flag(msg->skb, TIPC_NLA_MON_ACTIVE))
goto attr_msg_full;
if (nla_put_string(msg->skb, TIPC_NLA_MON_BEARER_NAME, bearer_name))
goto attr_msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_MON_PEERCNT, mon->peer_cnt))
goto attr_msg_full;
if (nla_put_u32(msg->skb, TIPC_NLA_MON_LISTGEN, mon->list_gen))
goto attr_msg_full;
read_unlock_bh(&mon->lock);
nla_nest_end(msg->skb, attrs);
genlmsg_end(msg->skb, hdr);
return 0;
attr_msg_full:
read_unlock_bh(&mon->lock);
nla_nest_cancel(msg->skb, attrs);
msg_full:
genlmsg_cancel(msg->skb, hdr);
return -EMSGSIZE;
}