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06bd2b1ed0
In commit 2d18ac4ba7 ("tipc: extend broadcast link initialization
criteria") we tried to fix a problem with the initial synchronization
of broadcast link acknowledge values. Unfortunately that solution is
not sufficient to solve the issue.
We have seen it happen that LINK_PROTOCOL/STATE packets with a valid
non-zero unicast acknowledge number may bypass BCAST_PROTOCOL
initialization, NAME_DISTRIBUTOR and other STATE packets with invalid
broadcast acknowledge numbers, leading to premature opening of the
broadcast link. When the bypassed packets finally arrive, they are
inadvertently accepted, and the already correctly initialized
acknowledge number in the broadcast receive link is overwritten by
the invalid (zero) value of the said packets. After this the broadcast
link goes stale.
We now fix this by marking the packets where we know the acknowledge
value is or may be invalid, and then ignoring the acks from those.
To this purpose, we claim an unused bit in the header to indicate that
the value is invalid. We set the bit to 1 in the initial BCAST_PROTOCOL
synchronization packet and all initial ("bulk") NAME_DISTRIBUTOR
packets, plus those LINK_PROTOCOL packets sent out before the broadcast
links are fully synchronized.
This minor protocol update is fully backwards compatible.
Reported-by: John Thompson <thompa.atl@gmail.com>
Tested-by: John Thompson <thompa.atl@gmail.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
81 lines
3.2 KiB
C
81 lines
3.2 KiB
C
/*
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* net/tipc/bcast.h: Include file for TIPC broadcast code
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*
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* Copyright (c) 2003-2006, 2014-2015, Ericsson AB
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* Copyright (c) 2005, 2010-2011, 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_BCAST_H
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#define _TIPC_BCAST_H
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#include "core.h"
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struct tipc_node;
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struct tipc_msg;
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struct tipc_nl_msg;
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struct tipc_node_map;
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extern const char tipc_bclink_name[];
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int tipc_bcast_init(struct net *net);
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void tipc_bcast_stop(struct net *net);
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void tipc_bcast_add_peer(struct net *net, struct tipc_link *l,
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struct sk_buff_head *xmitq);
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void tipc_bcast_remove_peer(struct net *net, struct tipc_link *rcv_bcl);
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void tipc_bcast_inc_bearer_dst_cnt(struct net *net, int bearer_id);
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void tipc_bcast_dec_bearer_dst_cnt(struct net *net, int bearer_id);
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int tipc_bcast_get_mtu(struct net *net);
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int tipc_bcast_xmit(struct net *net, struct sk_buff_head *list);
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int tipc_bcast_rcv(struct net *net, struct tipc_link *l, struct sk_buff *skb);
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void tipc_bcast_ack_rcv(struct net *net, struct tipc_link *l,
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struct tipc_msg *hdr);
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int tipc_bcast_sync_rcv(struct net *net, struct tipc_link *l,
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struct tipc_msg *hdr);
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int tipc_nl_add_bc_link(struct net *net, struct tipc_nl_msg *msg);
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int tipc_nl_bc_link_set(struct net *net, struct nlattr *attrs[]);
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int tipc_bclink_reset_stats(struct net *net);
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static inline void tipc_bcast_lock(struct net *net)
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{
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spin_lock_bh(&tipc_net(net)->bclock);
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}
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static inline void tipc_bcast_unlock(struct net *net)
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{
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spin_unlock_bh(&tipc_net(net)->bclock);
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}
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static inline struct tipc_link *tipc_bc_sndlink(struct net *net)
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{
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return tipc_net(net)->bcl;
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}
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#endif
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