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cb1b728096
linux-next/net/tipc/node.h
Jon Paul Maloy cb1b728096 tipc: eliminate race condition at multicast reception 
In a previous commit in this series we resolved a race problem during
unicast message reception.

Here, we resolve the same problem at multicast reception. We apply the
same technique: an input queue serializing the delivery of arriving
buffers. The main difference is that here we do it in two steps.
First, the broadcast link feeds arriving buffers into the tail of an
arrival queue, which head is consumed at the socket level, and where
destination lookup is performed. Second, if the lookup is successful,
the resulting buffer clones are fed into a second queue, the input
queue. This queue is consumed at reception in the socket just like
in the unicast case. Both queues are protected by the same lock, -the
one of the input queue.

Reviewed-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>
2015-02-05 16:00:03 -08:00

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/*
* net/tipc/node.h: Include file for TIPC node management routines
*
* Copyright (c) 2000-2006, 2014-2015, Ericsson AB
* Copyright (c) 2005, 2010-2014, 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_NODE_H
#define _TIPC_NODE_H
#include "addr.h"
#include "net.h"
#include "bearer.h"
#include "msg.h"
/* Out-of-range value for node signature */
#define INVALID_NODE_SIG 0x10000
#define NODE_HTABLE_SIZE 512
/* Flags used to take different actions according to flag type
* TIPC_WAIT_PEER_LINKS_DOWN: wait to see that peer's links are down
* TIPC_WAIT_OWN_LINKS_DOWN: wait until peer node is declared down
* TIPC_NOTIFY_NODE_DOWN: notify node is down
* TIPC_NOTIFY_NODE_UP: notify node is up
* TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
*/
enum {
TIPC_MSG_EVT = 1,
TIPC_WAIT_PEER_LINKS_DOWN = (1 << 1),
TIPC_WAIT_OWN_LINKS_DOWN = (1 << 2),
TIPC_NOTIFY_NODE_DOWN = (1 << 3),
TIPC_NOTIFY_NODE_UP = (1 << 4),
TIPC_WAKEUP_BCAST_USERS = (1 << 5),
TIPC_NOTIFY_LINK_UP = (1 << 6),
TIPC_NOTIFY_LINK_DOWN = (1 << 7),
TIPC_NAMED_MSG_EVT = (1 << 8),
TIPC_BCAST_MSG_EVT = (1 << 9)
};
/**
* struct tipc_node_bclink - TIPC node bclink structure
* @acked: sequence # of last outbound b'cast message acknowledged by node
* @last_in: sequence # of last in-sequence b'cast message received from node
* @last_sent: sequence # of last b'cast message sent by node
* @oos_state: state tracker for handling OOS b'cast messages
* @deferred_queue: deferred queue saved OOS b'cast message received from node
* @reasm_buf: broadcast reassembly queue head from node
* @inputq_map: bitmap indicating which inqueues should be kicked
* @recv_permitted: true if node is allowed to receive b'cast messages
*/
struct tipc_node_bclink {
u32 acked;
u32 last_in;
u32 last_sent;
u32 oos_state;
u32 deferred_size;
struct sk_buff_head deferred_queue;
struct sk_buff *reasm_buf;
int inputq_map;
bool recv_permitted;
};
/**
* struct tipc_node - TIPC node structure
* @addr: network address of node
* @lock: spinlock governing access to structure
* @net: the applicable net namespace
* @hash: links to adjacent nodes in unsorted hash chain
* @inputq: pointer to input queue containing messages for msg event
* @namedq: pointer to name table input queue with name table messages
* @curr_link: the link holding the node lock, if any
* @active_links: pointers to active links to node
* @links: pointers to all links to node
* @action_flags: bit mask of different types of node actions
* @bclink: broadcast-related info
* @list: links to adjacent nodes in sorted list of cluster's nodes
* @working_links: number of working links to node (both active and standby)
* @link_cnt: number of links to node
* @signature: node instance identifier
* @link_id: local and remote bearer ids of changing link, if any
* @publ_list: list of publications
* @rcu: rcu struct for tipc_node
*/
struct tipc_node {
u32 addr;
spinlock_t lock;
struct net *net;
struct hlist_node hash;
struct sk_buff_head *inputq;
struct sk_buff_head *namedq;
struct tipc_link *active_links[2];
u32 act_mtus[2];
struct tipc_link *links[MAX_BEARERS];
int action_flags;
struct tipc_node_bclink bclink;
struct list_head list;
int link_cnt;
int working_links;
u32 signature;
u32 link_id;
struct list_head publ_list;
struct list_head conn_sks;
struct rcu_head rcu;
};
struct tipc_node *tipc_node_find(struct net *net, u32 addr);
struct tipc_node *tipc_node_create(struct net *net, u32 addr);
void tipc_node_stop(struct net *net);
void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
int tipc_node_active_links(struct tipc_node *n_ptr);
int tipc_node_is_up(struct tipc_node *n_ptr);
struct sk_buff *tipc_node_get_links(struct net *net, const void *req_tlv_area,
int req_tlv_space);
struct sk_buff *tipc_node_get_nodes(struct net *net, const void *req_tlv_area,
int req_tlv_space);
int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 node,
char *linkname, size_t len);
void tipc_node_unlock(struct tipc_node *node);
int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port);
void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port);
int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb);
static inline void tipc_node_lock(struct tipc_node *node)
{
spin_lock_bh(&node->lock);
}
static inline bool tipc_node_blocked(struct tipc_node *node)
{
return (node->action_flags & (TIPC_WAIT_PEER_LINKS_DOWN |
TIPC_NOTIFY_NODE_DOWN | TIPC_WAIT_OWN_LINKS_DOWN));
}
static inline uint tipc_node_get_mtu(struct net *net, u32 addr, u32 selector)
{
struct tipc_node *node;
u32 mtu;
node = tipc_node_find(net, addr);
if (likely(node))
mtu = node->act_mtus[selector & 1];
else
mtu = MAX_MSG_SIZE;
return mtu;
}
#endif
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