![Erik Hugne](/assets/img/avatar_default.png)
TIPC name table updates are distributed asynchronously in a cluster, entailing a risk of certain race conditions. E.g., if two nodes simultaneously issue conflicting (overlapping) publications, this may not be detected until both publications have reached a third node, in which case one of the publications will be silently dropped on that node. Hence, we end up with an inconsistent name table. In most cases this conflict is just a temporary race, e.g., one node is issuing a publication under the assumption that a previous, conflicting, publication has already been withdrawn by the other node. However, because of the (rtt related) distributed update delay, this may not yet hold true on all nodes. The symptom of this failure is a syslog message: "tipc: Cannot publish {%u,%u,%u}, overlap error". In this commit we add a resiliency queue at the receiving end of the name table distributor. When insertion of an arriving publication fails, we retain it in this queue for a short amount of time, assuming that another update will arrive very soon and clear the conflict. If so happens, we insert the publication, otherwise we drop it. The (configurable) retention value defaults to 2000 ms. Knowing from experience that the situation described above is extremely rare, there is no risk that the queue will accumulate any large number of items. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
208 lines
6.3 KiB
C
208 lines
6.3 KiB
C
/*
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* net/tipc/core.h: Include file for TIPC global declarations
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*
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* Copyright (c) 2005-2006, 2013 Ericsson AB
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* Copyright (c) 2005-2007, 2010-2013, 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_CORE_H
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#define _TIPC_CORE_H
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/tipc.h>
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#include <linux/tipc_config.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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#include <linux/interrupt.h>
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#include <linux/atomic.h>
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#include <asm/hardirq.h>
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#include <linux/netdevice.h>
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#include <linux/in.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/rtnetlink.h>
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#include <linux/etherdevice.h>
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#define TIPC_MOD_VER "2.0.0"
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#define ULTRA_STRING_MAX_LEN 32768
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#define TIPC_MAX_SUBSCRIPTIONS 65535
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#define TIPC_MAX_PUBLICATIONS 65535
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struct tipc_msg; /* msg.h */
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int tipc_snprintf(char *buf, int len, const char *fmt, ...);
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/*
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* TIPC-specific error codes
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*/
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#define ELINKCONG EAGAIN /* link congestion <=> resource unavailable */
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/*
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* Global configuration variables
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*/
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extern u32 tipc_own_addr __read_mostly;
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extern int tipc_max_ports __read_mostly;
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extern int tipc_net_id __read_mostly;
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extern int sysctl_tipc_rmem[3] __read_mostly;
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extern int sysctl_tipc_named_timeout __read_mostly;
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/*
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* Other global variables
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*/
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extern int tipc_random __read_mostly;
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/*
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* Routines available to privileged subsystems
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*/
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int tipc_netlink_start(void);
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void tipc_netlink_stop(void);
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int tipc_socket_init(void);
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void tipc_socket_stop(void);
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int tipc_sock_create_local(int type, struct socket **res);
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void tipc_sock_release_local(struct socket *sock);
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int tipc_sock_accept_local(struct socket *sock, struct socket **newsock,
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int flags);
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#ifdef CONFIG_SYSCTL
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int tipc_register_sysctl(void);
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void tipc_unregister_sysctl(void);
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#else
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#define tipc_register_sysctl() 0
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#define tipc_unregister_sysctl()
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#endif
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/*
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* TIPC timer code
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*/
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typedef void (*Handler) (unsigned long);
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/**
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* k_init_timer - initialize a timer
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* @timer: pointer to timer structure
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* @routine: pointer to routine to invoke when timer expires
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* @argument: value to pass to routine when timer expires
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*
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* Timer must be initialized before use (and terminated when no longer needed).
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*/
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static inline void k_init_timer(struct timer_list *timer, Handler routine,
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unsigned long argument)
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{
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setup_timer(timer, routine, argument);
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}
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/**
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* k_start_timer - start a timer
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* @timer: pointer to timer structure
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* @msec: time to delay (in ms)
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*
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* Schedules a previously initialized timer for later execution.
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* If timer is already running, the new timeout overrides the previous request.
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*
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* To ensure the timer doesn't expire before the specified delay elapses,
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* the amount of delay is rounded up when converting to the jiffies
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* then an additional jiffy is added to account for the fact that
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* the starting time may be in the middle of the current jiffy.
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*/
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static inline void k_start_timer(struct timer_list *timer, unsigned long msec)
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{
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mod_timer(timer, jiffies + msecs_to_jiffies(msec) + 1);
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}
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/**
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* k_cancel_timer - cancel a timer
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* @timer: pointer to timer structure
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*
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* Cancels a previously initialized timer.
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* Can be called safely even if the timer is already inactive.
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*
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* WARNING: Must not be called when holding locks required by the timer's
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* timeout routine, otherwise deadlock can occur on SMP systems!
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*/
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static inline void k_cancel_timer(struct timer_list *timer)
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{
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del_timer_sync(timer);
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}
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/**
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* k_term_timer - terminate a timer
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* @timer: pointer to timer structure
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*
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* Prevents further use of a previously initialized timer.
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*
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* WARNING: Caller must ensure timer isn't currently running.
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*
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* (Do not "enhance" this routine to automatically cancel an active timer,
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* otherwise deadlock can arise when a timeout routine calls k_term_timer.)
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*/
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static inline void k_term_timer(struct timer_list *timer)
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{
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}
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/*
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* TIPC message buffer code
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*
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* TIPC message buffer headroom reserves space for the worst-case
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* link-level device header (in case the message is sent off-node).
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*
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* Note: Headroom should be a multiple of 4 to ensure the TIPC header fields
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* are word aligned for quicker access
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*/
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#define BUF_HEADROOM LL_MAX_HEADER
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struct tipc_skb_cb {
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void *handle;
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struct sk_buff *tail;
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bool deferred;
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bool wakeup_pending;
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u16 chain_sz;
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u16 chain_imp;
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};
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#define TIPC_SKB_CB(__skb) ((struct tipc_skb_cb *)&((__skb)->cb[0]))
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static inline struct tipc_msg *buf_msg(struct sk_buff *skb)
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{
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return (struct tipc_msg *)skb->data;
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}
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struct sk_buff *tipc_buf_acquire(u32 size);
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#endif
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