linux/net/tipc
Jon Paul Maloy 06bd2b1ed0 tipc: fix broadcast link synchronization problem
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>
2016-10-29 17:21:09 -04:00
..
addr.c tipc: simplify include dependencies 2015-05-14 12:24:45 -04:00
addr.h tipc: introduce constants for tipc address validation 2016-07-26 14:26:42 -07:00
bcast.c tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
bcast.h tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
bearer.c tipc: add the ability to get UDP options via netlink 2016-08-26 21:38:41 -07:00
bearer.h tipc: introduce UDP replicast 2016-08-26 21:38:41 -07:00
core.c tipc: add neighbor monitoring framework 2016-06-15 14:06:28 -07:00
core.h tipc: add neighbor monitoring framework 2016-06-15 14:06:28 -07:00
discover.c tipc: honor msg2addr return value 2016-06-29 05:17:37 -04:00
discover.h tipc: eliminate buffer leak in bearer layer 2016-04-07 17:00:13 -04:00
eth_media.c tipc: make media address offset a common define 2015-02-27 18:18:48 -05:00
ib_media.c tipc: rename media/msg related definitions 2015-02-27 18:18:48 -05:00
Kconfig tipc: add ip/udp media type 2015-03-05 22:08:42 -05:00
link.c tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
link.h tipc: transfer broadcast nacks in link state messages 2016-09-02 17:10:24 -07:00
Makefile tipc: add neighbor monitoring framework 2016-06-15 14:06:28 -07:00
monitor.c tipc: fix variable dereference before NULL check 2016-08-10 17:56:52 -07:00
monitor.h tipc: dump monitor attributes 2016-07-26 14:26:42 -07:00
msg.c tipc: unclone unbundled buffers before forwarding 2016-06-22 16:33:35 -04:00
msg.h tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
name_distr.c tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
name_distr.h tipc: reduce code dependency between binding table and node layer 2015-11-20 14:06:10 -05:00
name_table.c tipc: move netlink policies to netlink.c 2016-03-07 14:56:41 -05:00
name_table.h tipc: convert legacy nl name table dump to nl compat 2015-02-09 13:20:48 -08:00
net.c tipc: move netlink policies to netlink.c 2016-03-07 14:56:41 -05:00
net.h tipc: add peer removal functionality 2016-08-18 23:36:07 -07:00
netlink_compat.c tipc: fix nl compat regression for link statistics 2016-07-01 16:47:38 -04:00
netlink.c tipc: add UDP remoteip dump to netlink API 2016-08-26 21:38:41 -07:00
netlink.h tipc: make cluster size threshold for monitoring configurable 2016-07-26 14:26:42 -07:00
node.c tipc: fix broadcast link synchronization problem 2016-10-29 17:21:09 -04:00
node.h tipc: transfer broadcast nacks in link state messages 2016-09-02 17:10:24 -07:00
server.c tipc: Use kmemdup instead of kmalloc and memcpy 2016-06-27 09:56:58 -04:00
server.h tipc: fix a race condition leading to subscriber refcnt bug 2016-04-14 16:46:46 -04:00
socket.c tipc: fix NULL pointer dereference in shutdown() 2016-08-15 13:55:36 -07:00
socket.h tipc: redesign connection-level flow control 2016-05-03 15:51:16 -04:00
subscr.c tipc: remove an unnecessary NULL check 2016-04-28 16:54:12 -04:00
subscr.h tipc: remove struct tipc_name_seq from struct tipc_subscription 2016-02-06 03:40:43 -05:00
sysctl.c tipc: add name distributor resiliency queue 2014-09-01 17:51:48 -07:00
udp_media.c tipc: info leak in __tipc_nl_add_udp_addr() 2016-10-13 12:10:01 -04:00
udp_media.h tipc: add UDP remoteip dump to netlink API 2016-08-26 21:38:41 -07:00