0x7d and 0x7e bytes are meant to be escaped in the data portion of
frames, but this didn't occur since next_chunk_len() had an off-by-one
error. That also resulted in the final byte of a payload being written
as a separate tty write op.
The chunk prior to an escaped byte would be one byte short, and the
next call would never test the txpos+1 case, which is where the escaped
byte was located. That meant it never hit the escaping case in
mctp_serial_tx_work().
Example Input: 01 00 08 c8 7e 80 02
Previous incorrect chunks from next_chunk_len():
01 00 08
c8 7e 80
02
With this fix:
01 00 08 c8
7e
80 02
Cc: stable@vger.kernel.org
Fixes: a0c2ccd9b5 ("mctp: Add MCTP-over-serial transport binding")
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Test various edge cases of inputs that contain characters
that need escaping.
This adds a new kunit suite for mctp-serial.
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
RFC1662 defines the start state for the crc16 FCS to be 0xffff, but
we're currently starting at zero.
This change uses the correct start state. We're only early in the
adoption for the serial binding, so there aren't yet any other users to
interface to.
Fixes: a0c2ccd9b5 ("mctp: Add MCTP-over-serial transport binding")
Reported-by: Harsh Tyagi <harshtya@google.com>
Tested-by: Harsh Tyagi <harshtya@google.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit
baebdf48c3 ("net: dev: Makes sure netif_rx() can be invoked in any context.")
the function netif_rx() can be used in preemptible/thread context as
well as in interrupt context.
Use netif_rx().
Cc: Jeremy Kerr <jk@codeconstruct.com.au>
Cc: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jiri assures me that a ldisc->open with tty->disc_data set should never
happen, so this check doesn't do anything.
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The current serial driver requires a maximum MTU of 68, and it doesn't
make sense to set a MTU below the MCTP-required baseline (of 68) either.
This change sets the min_mtu & max_mtu of the mctp netdev, essentially
disallowing changes. By using these instead of a ndo_change_mtu op, we
get the netlink extacks reported too.
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We want to ensure that the tx work has finished before returning from
the ldisc close op, so do a synchronous cancel.
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This change adds a MCTP Serial transport binding, as defined by DMTF
specificiation DSP0253 - "MCTP Serial Transport Binding". This is
implemented as a new serial line discipline, and can be attached to
arbitrary tty devices.
From the Kconfig description:
This driver provides an MCTP-over-serial interface, through a
serial line-discipline, as defined by DMTF specification "DSP0253 -
MCTP Serial Transport Binding". By attaching the ldisc to a serial
device, we get a new net device to transport MCTP packets.
This allows communication with external MCTP endpoints which use
serial as their transport. It can also be used as an easy way to
provide MCTP connectivity between virtual machines, by forwarding
data between simple virtual serial devices.
Say y here if you need to connect to MCTP endpoints over serial. To
compile as a module, use m; the module will be called mctp-serial.
Once the N_MCTP line discipline is set [using ioctl(TCIOSETD)], we get a
new netdev suitable for MCTP communication.
The 'mctp' utility[1] provides a simple wrapper for this ioctl, using
'link serial <device>':
# mctp link serial /dev/ttyS0 &
# mctp link
dev lo index 1 address 0x00:00:00:00:00:00 net 1 mtu 65536 up
dev mctpserial0 index 5 address 0x(no-addr) net 1 mtu 68 down
[1]: https://github.com/CodeConstruct/mctp
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
