2222a78075
During the 4-way handshake, the transport's state is set to ACTIVE in
sctp_process_init() when processing INIT_ACK chunk on client or
COOKIE_ECHO chunk on server.
In the collision scenario below:
192.168.1.2 > 192.168.1.1: sctp (1) [INIT] [init tag: 3922216408]
192.168.1.1 > 192.168.1.2: sctp (1) [INIT] [init tag: 144230885]
192.168.1.2 > 192.168.1.1: sctp (1) [INIT ACK] [init tag: 3922216408]
192.168.1.1 > 192.168.1.2: sctp (1) [COOKIE ECHO]
192.168.1.2 > 192.168.1.1: sctp (1) [COOKIE ACK]
192.168.1.1 > 192.168.1.2: sctp (1) [INIT ACK] [init tag: 3914796021]
when processing COOKIE_ECHO on 192.168.1.2, as it's in COOKIE_WAIT state,
sctp_sf_do_dupcook_b() is called by sctp_sf_do_5_2_4_dupcook() where it
creates a new association and sets its transport to ACTIVE then updates
to the old association in sctp_assoc_update().
However, in sctp_assoc_update(), it will skip the transport update if it
finds a transport with the same ipaddr already existing in the old asoc,
and this causes the old asoc's transport state not to move to ACTIVE
after the handshake.
This means if DATA retransmission happens at this moment, it won't be able
to enter PF state because of the check 'transport->state == SCTP_ACTIVE'
in sctp_do_8_2_transport_strike().
This patch fixes it by updating the transport in sctp_assoc_update() with
sctp_assoc_add_peer() where it updates the transport state if there is
already a transport with the same ipaddr exists in the old asoc.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/fd17356abe49713ded425250cc1ae51e9f5846c6.1696172325.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.