X.25 Layer 3 (the Packet Layer) expects layer 2 to provide a reliable
datalink service such that no packets are reordered or dropped. And
X.25 Layer 2 (the LAPB layer) is indeed designed to provide such service.
However, this reliability is not preserved when a driver calls "netif_rx"
to deliver the received packets to layer 3, because "netif_rx" will put
the packets into per-CPU queues before they are delivered to layer 3.
If there are multiple CPUs, the order of the packets may not be preserved.
The per-CPU queues may also drop packets if there are too many.
Therefore, we should not call "netif_rx" to let it queue the packets.
Instead, we should use our own queue that won't reorder or drop packets.
This patch changes all X.25 drivers to use their own queues instead of
calling "netif_rx". The patch also documents this requirement in the
"x25-iface" documentation.
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
"x25_close" is called by "hdlc_close" in "hdlc.c", which is called by
hardware drivers' "ndo_stop" function.
"x25_xmit" is called by "hdlc_start_xmit" in "hdlc.c", which is hardware
drivers' "ndo_start_xmit" function.
"x25_rx" is called by "hdlc_rcv" in "hdlc.c", which receives HDLC frames
from "net/core/dev.c".
"x25_close" races with "x25_xmit" and "x25_rx" because their callers race.
However, we need to ensure that the LAPB APIs called in "x25_xmit" and
"x25_rx" are called before "lapb_unregister" is called in "x25_close".
This patch adds locking to ensure when "x25_xmit" and "x25_rx" are doing
their work, "lapb_unregister" is not yet called in "x25_close".
Reasons for not solving the racing between "x25_close" and "x25_xmit" by
calling "netif_tx_disable" in "x25_close":
1. We still need to solve the racing between "x25_close" and "x25_rx";
2. The design of the HDLC subsystem assumes the HDLC hardware drivers
have full control over the TX queue, and the HDLC protocol drivers (like
this driver) have no control. Controlling the queue here in the protocol
driver may interfere with hardware drivers' control of the queue.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's not meaningful to pass on LAPB error codes to HDLC code or other
parts of the system, because they will not understand the error codes.
Instead, use system-wide recognizable error codes.
Fixes: f362e5fe0f ("wan/hdlc_x25: make lapb params configurable")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Martin Schiller <ms@dev.tdt.de>
Link: https://lore.kernel.org/r/20210203071541.86138-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
1. In x25_xmit, skb_reset_network_header is not necessary before we call
lapb_data_request. The lapb module doesn't need skb->network_header.
So there is no need to set skb->network_header before calling
lapb_data_request.
2. In x25_data_indication (called by the lapb module after data have
been received), skb_reset_network_header is not necessary before we
call netif_rx. After we call netif_rx, the code in net/core/dev.c will
call skb_reset_network_header before handing the skb to upper layers
(in __netif_receive_skb_core, called by __netif_receive_skb_one_core,
called by __netif_receive_skb, called by process_backlog). So we don't
need to call skb_reset_network_header by ourselves.
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1. Added a skb->len check
This driver expects upper layers to include a pseudo header of 1 byte
when passing down a skb for transmission. This driver will read this
1-byte header. This patch added a skb->len check before reading the
header to make sure the header exists.
2. Added needed_headroom and set hard_header_len to 0
When this driver transmits data,
first this driver will remove a pseudo header of 1 byte,
then the lapb module will prepend the LAPB header of 2 or 3 bytes.
So the value of needed_headroom in this driver should be 3 - 1.
Because this driver has no header_ops, according to the logic of
af_packet.c, the value of hard_header_len should be 0.
Reason of setting needed_headroom and hard_header_len at this place:
This driver is written using the API of the hdlc module, the hdlc
module enables this driver (the protocol driver) to run on any hardware
that has a driver (the hardware driver) written using the API of the
hdlc module.
Two other hdlc protocol drivers - hdlc_ppp and hdlc_raw_eth, also set
things like hard_header_len at this place. In hdlc_ppp, it sets
hard_header_len after attach_hdlc_protocol and before setting dev->type.
In hdlc_raw_eth, it sets hard_header_len by calling ether_setup after
attach_hdlc_protocol and after memcpy the settings.
3. Reset needed_headroom when detaching protocols (in hdlc.c)
When detaching a protocol from a hardware device, the hdlc module will
reset various parameters of the device (including hard_header_len) to
the default values. We add needed_headroom here so that needed_headroom
will also be reset.
Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixed 2 issues with the usage of skb_cow in LAPB drivers
"lapbether" and "hdlc_x25":
1) After skb_cow fails, kfree_skb should be called to drop a reference
to the skb. But in both drivers, kfree_skb is not called.
2) skb_cow should be called before skb_push so that is can ensure the
safety of skb_push. But in "lapbether", it is incorrectly called after
skb_push.
More details about these 2 issues:
1) The behavior of calling kfree_skb on failure is also the behavior of
netif_rx, which is called by this function with "return netif_rx(skb);".
So this function should follow this behavior, too.
2) In "lapbether", skb_cow is called after skb_push. This results in 2
logical issues:
a) skb_push is not protected by skb_cow;
b) An extra headroom of 1 byte is ensured after skb_push. This extra
headroom has no use in this function. It also has no use in the
upper-layer function that this function passes the skb to
(x25_lapb_receive_frame in net/x25/x25_dev.c).
So logically skb_cow should instead be called before skb_push.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/wan/hdlc_x25.c: In function ‘x25_ioctl’:
drivers/net/wan/hdlc_x25.c:256:7: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
256 | if (ifr->ifr_settings.size = 0) {
| ^~~
Signed-off-by: David S. Miller <davem@davemloft.net>
o call skb_reset_network_header() before hdlc->xmit()
o change skb proto to HDLC (0x0019) before hdlc->xmit()
o call dev_queue_xmit_nit() before hdlc->xmit()
This changes make it possible to trace (tcpdump) outgoing layer2
(ETH_P_HDLC) packets
Additionally call skb_reset_network_header() after each skb_push() /
skb_pull().
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This enables you to configure mode (DTE/DCE), Modulo, Window, T1, T2, N2 via
sethdlc (which needs to be patched as well).
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of version 2 of the gnu general public license as
published by the free software foundation
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 107 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.615055994@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
An HDLC device can change type when the protocol driver is changed.
Calling the notifier change allows potential users of the interface
know about this planned change, and even block it. After the change
has occurred, send a second notification to users can evaluate the new
device type etc.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is compile tested only.
Suggested by dumpster diving in PAX.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use pr_fmt, pr_<level> and netdev_<level> as appropriate.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change magic numbers to identifiers for X25 interface.
Signed-off-by: Andrew Hendry <andrew.hendry@gmail.com>
Acked-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Added a space separating some if/switch/while keywords from the following
parenthesis to conform to the CodingStyle.
Signed-off-by: Rudy Matela <rudy.matela@gmail.com>
Acked-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Also remove unneeded last_rx update from Synclink drivers.
Synclink part mostly by Stephen Hemminger.
Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
WAN: fixes a NULL dereference in hdlc_x25.
Reported-by: Adrian Bunk <bunk@kernel.org>.
Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There is no point in using separate net_device_stats structs when
the one in struct net_device is present. Compiles.
Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Switching HDLC devices from Ethernet-framing mode caused stale ethernet
function assignments within net_device.
Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch enables building of individual WAN protocol support
routines (parts of generic HDLC) as separate modules.
All protocol-private definitions are moved from hdlc.h file
to protocol drivers. User-space interface and interface
between generic HDLC and underlying low-level HDLC drivers
are unchanged.
Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
WAN: Fixed a problem with PPP/raw HDLC/X.25 protocols not doing
netif_dormant_off() at startup.
Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
