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TIPC node hash node table is protected with rcu lock on read side. tipc_node_find() is used to look for a node object with node address through iterating the hash node table. As the entire process of what tipc_node_find() traverses the table is guarded with rcu read lock, it's safe for us. However, when callers use the node object returned by tipc_node_find(), there is no rcu read lock applied. Therefore, this is absolutely unsafe for callers of tipc_node_find(). Now we introduce a reference counter for node structure. Before tipc_node_find() returns node object to its caller, it first increases the reference counter. Accordingly, after its caller used it up, it decreases the counter again. This can prevent a node being used by one thread from being freed by another thread. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
188 lines
6.7 KiB
C
188 lines
6.7 KiB
C
/*
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* net/tipc/node.h: Include file for TIPC node management routines
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*
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* Copyright (c) 2000-2006, 2014-2015, Ericsson AB
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* Copyright (c) 2005, 2010-2014, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _TIPC_NODE_H
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#define _TIPC_NODE_H
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#include "addr.h"
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#include "net.h"
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#include "bearer.h"
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#include "msg.h"
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/* Out-of-range value for node signature */
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#define INVALID_NODE_SIG 0x10000
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#define NODE_HTABLE_SIZE 512
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/* Flags used to take different actions according to flag type
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* TIPC_WAIT_PEER_LINKS_DOWN: wait to see that peer's links are down
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* TIPC_WAIT_OWN_LINKS_DOWN: wait until peer node is declared down
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* TIPC_NOTIFY_NODE_DOWN: notify node is down
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* TIPC_NOTIFY_NODE_UP: notify node is up
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* TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
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*/
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enum {
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TIPC_MSG_EVT = 1,
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TIPC_WAIT_PEER_LINKS_DOWN = (1 << 1),
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TIPC_WAIT_OWN_LINKS_DOWN = (1 << 2),
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TIPC_NOTIFY_NODE_DOWN = (1 << 3),
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TIPC_NOTIFY_NODE_UP = (1 << 4),
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TIPC_WAKEUP_BCAST_USERS = (1 << 5),
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TIPC_NOTIFY_LINK_UP = (1 << 6),
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TIPC_NOTIFY_LINK_DOWN = (1 << 7),
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TIPC_NAMED_MSG_EVT = (1 << 8),
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TIPC_BCAST_MSG_EVT = (1 << 9),
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TIPC_BCAST_RESET = (1 << 10)
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};
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/**
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* struct tipc_node_bclink - TIPC node bclink structure
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* @acked: sequence # of last outbound b'cast message acknowledged by node
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* @last_in: sequence # of last in-sequence b'cast message received from node
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* @last_sent: sequence # of last b'cast message sent by node
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* @oos_state: state tracker for handling OOS b'cast messages
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* @deferred_queue: deferred queue saved OOS b'cast message received from node
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* @reasm_buf: broadcast reassembly queue head from node
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* @inputq_map: bitmap indicating which inqueues should be kicked
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* @recv_permitted: true if node is allowed to receive b'cast messages
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*/
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struct tipc_node_bclink {
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u32 acked;
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u32 last_in;
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u32 last_sent;
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u32 oos_state;
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u32 deferred_size;
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struct sk_buff_head deferdq;
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struct sk_buff *reasm_buf;
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int inputq_map;
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bool recv_permitted;
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};
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/**
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* struct tipc_node - TIPC node structure
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* @addr: network address of node
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* @ref: reference counter to node object
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* @lock: spinlock governing access to structure
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* @net: the applicable net namespace
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* @hash: links to adjacent nodes in unsorted hash chain
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* @inputq: pointer to input queue containing messages for msg event
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* @namedq: pointer to name table input queue with name table messages
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* @curr_link: the link holding the node lock, if any
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* @active_links: pointers to active links to node
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* @links: pointers to all links to node
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* @action_flags: bit mask of different types of node actions
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* @bclink: broadcast-related info
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* @list: links to adjacent nodes in sorted list of cluster's nodes
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* @working_links: number of working links to node (both active and standby)
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* @link_cnt: number of links to node
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* @capabilities: bitmap, indicating peer node's functional capabilities
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* @signature: node instance identifier
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* @link_id: local and remote bearer ids of changing link, if any
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* @publ_list: list of publications
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* @rcu: rcu struct for tipc_node
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*/
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struct tipc_node {
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u32 addr;
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struct kref kref;
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spinlock_t lock;
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struct net *net;
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struct hlist_node hash;
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struct sk_buff_head *inputq;
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struct sk_buff_head *namedq;
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struct tipc_link *active_links[2];
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u32 act_mtus[2];
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struct tipc_link *links[MAX_BEARERS];
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int action_flags;
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struct tipc_node_bclink bclink;
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struct list_head list;
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int link_cnt;
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u16 working_links;
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u16 capabilities;
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u32 signature;
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u32 link_id;
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struct list_head publ_list;
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struct list_head conn_sks;
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struct rcu_head rcu;
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};
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struct tipc_node *tipc_node_find(struct net *net, u32 addr);
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void tipc_node_put(struct tipc_node *node);
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struct tipc_node *tipc_node_create(struct net *net, u32 addr);
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void tipc_node_stop(struct net *net);
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void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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int tipc_node_active_links(struct tipc_node *n_ptr);
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int tipc_node_is_up(struct tipc_node *n_ptr);
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int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 node,
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char *linkname, size_t len);
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void tipc_node_unlock(struct tipc_node *node);
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int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port);
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void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port);
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int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb);
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static inline void tipc_node_lock(struct tipc_node *node)
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{
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spin_lock_bh(&node->lock);
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}
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static inline bool tipc_node_blocked(struct tipc_node *node)
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{
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return (node->action_flags & (TIPC_WAIT_PEER_LINKS_DOWN |
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TIPC_NOTIFY_NODE_DOWN | TIPC_WAIT_OWN_LINKS_DOWN));
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}
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static inline uint tipc_node_get_mtu(struct net *net, u32 addr, u32 selector)
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{
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struct tipc_node *node;
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u32 mtu;
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node = tipc_node_find(net, addr);
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if (likely(node)) {
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mtu = node->act_mtus[selector & 1];
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tipc_node_put(node);
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} else {
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mtu = MAX_MSG_SIZE;
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}
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return mtu;
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}
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#endif
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