linux-brain/net/tipc/name_table.h
Jon Maloy 988f3f1603 tipc: eliminate message disordering during binding table update
We have seen the following race scenario:
1) named_distribute() builds a "bulk" message, containing a PUBLISH
   item for a certain publication. This is based on the contents of
   the binding tables's 'cluster_scope' list.
2) tipc_named_withdraw() removes the same publication from the list,
   bulds a WITHDRAW message and distributes it to all cluster nodes.
3) tipc_named_node_up(), which was calling named_distribute(), sends
   out the bulk message built under 1)
4) The WITHDRAW message arrives at the just detected node, finds
   no corresponding publication, and is dropped.
5) The PUBLISH item arrives at the same node, is added to its binding
   table, and remains there forever.

This arrival disordering was earlier taken care of by the backlog queue,
originally added for a different purpose, which was removed in the
commit referred to below, but we now need a different solution.
In this commit, we replace the rcu lock protecting the 'cluster_scope'
list with a regular RW lock which comprises even the sending of the
bulk message. This both guarantees both the list integrity and the
message sending order. We will later add a commit which cleans up
this code further.

Note that this commit needs recently added commit d3092b2efc ("tipc:
fix unsafe rcu locking when accessing publication list") to apply
cleanly.

Fixes: 37922ea4a3 ("tipc: permit overlapping service ranges in name table")
Reported-by: Tuong Lien Tong <tuong.t.lien@dektech.com.au>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22 19:29:12 -07:00

149 lines
6.1 KiB
C

/*
* net/tipc/name_table.h: Include file for TIPC name table code
*
* Copyright (c) 2000-2006, 2014-2018, Ericsson AB
* Copyright (c) 2004-2005, 2010-2011, 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.
*/
#ifndef _TIPC_NAME_TABLE_H
#define _TIPC_NAME_TABLE_H
struct tipc_subscription;
struct tipc_plist;
struct tipc_nlist;
struct tipc_group;
/*
* TIPC name types reserved for internal TIPC use (both current and planned)
*/
#define TIPC_ZM_SRV 3 /* zone master service name type */
#define TIPC_PUBL_SCOPE_NUM (TIPC_NODE_SCOPE + 1)
#define TIPC_NAMETBL_SIZE 1024 /* must be a power of 2 */
/**
* struct publication - info about a published (name or) name sequence
* @type: name sequence type
* @lower: name sequence lower bound
* @upper: name sequence upper bound
* @scope: scope of publication, TIPC_NODE_SCOPE or TIPC_CLUSTER_SCOPE
* @node: network address of publishing socket's node
* @port: publishing port
* @key: publication key, unique across the cluster
* @binding_node: all publications from the same node which bound this one
* - Remote publications: in node->publ_list
* Used by node/name distr to withdraw publications when node is lost
* - Local/node scope publications: in name_table->node_scope list
* - Local/cluster scope publications: in name_table->cluster_scope list
* @binding_sock: all publications from the same socket which bound this one
* Used by socket to withdraw publications when socket is unbound/released
* @local_publ: list of identical publications made from this node
* Used by closest_first and multicast receive lookup algorithms
* @all_publ: all publications identical to this one, whatever node and scope
* Used by round-robin lookup algorithm
* @rcu: RCU callback head used for deferred freeing
*/
struct publication {
u32 type;
u32 lower;
u32 upper;
u32 scope;
u32 node;
u32 port;
u32 key;
struct list_head binding_node;
struct list_head binding_sock;
struct list_head local_publ;
struct list_head all_publ;
struct rcu_head rcu;
};
/**
* struct name_table - table containing all existing port name publications
* @seq_hlist: name sequence hash lists
* @node_scope: all local publications with node scope
* - used by name_distr during re-init of name table
* @cluster_scope: all local publications with cluster scope
* - used by name_distr to send bulk updates to new nodes
* - used by name_distr during re-init of name table
* @local_publ_count: number of publications issued by this node
*/
struct name_table {
struct hlist_head services[TIPC_NAMETBL_SIZE];
struct list_head node_scope;
struct list_head cluster_scope;
rwlock_t cluster_scope_lock;
u32 local_publ_count;
};
int tipc_nl_name_table_dump(struct sk_buff *skb, struct netlink_callback *cb);
u32 tipc_nametbl_translate(struct net *net, u32 type, u32 instance, u32 *node);
void tipc_nametbl_mc_lookup(struct net *net, u32 type, u32 lower, u32 upper,
u32 scope, bool exact, struct list_head *dports);
void tipc_nametbl_build_group(struct net *net, struct tipc_group *grp,
u32 type, u32 domain);
void tipc_nametbl_lookup_dst_nodes(struct net *net, u32 type, u32 lower,
u32 upper, struct tipc_nlist *nodes);
bool tipc_nametbl_lookup(struct net *net, u32 type, u32 instance, u32 domain,
struct list_head *dsts, int *dstcnt, u32 exclude,
bool all);
struct publication *tipc_nametbl_publish(struct net *net, u32 type, u32 lower,
u32 upper, u32 scope, u32 port,
u32 key);
int tipc_nametbl_withdraw(struct net *net, u32 type, u32 lower, u32 upper,
u32 key);
struct publication *tipc_nametbl_insert_publ(struct net *net, u32 type,
u32 lower, u32 upper, u32 scope,
u32 node, u32 ref, u32 key);
struct publication *tipc_nametbl_remove_publ(struct net *net, u32 type,
u32 lower, u32 upper,
u32 node, u32 key);
bool tipc_nametbl_subscribe(struct tipc_subscription *s);
void tipc_nametbl_unsubscribe(struct tipc_subscription *s);
int tipc_nametbl_init(struct net *net);
void tipc_nametbl_stop(struct net *net);
struct tipc_dest {
struct list_head list;
u32 port;
u32 node;
};
struct tipc_dest *tipc_dest_find(struct list_head *l, u32 node, u32 port);
bool tipc_dest_push(struct list_head *l, u32 node, u32 port);
bool tipc_dest_pop(struct list_head *l, u32 *node, u32 *port);
bool tipc_dest_del(struct list_head *l, u32 node, u32 port);
void tipc_dest_list_purge(struct list_head *l);
int tipc_dest_list_len(struct list_head *l);
#endif