Commit d9d6ef25 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by David S. Miller

docs: networking: convert netconsole.txt to ReST

- add SPDX header;
- add a document title;
- mark code blocks and literals as such;
- mark tables as such;
- add notes markups;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e98aa682
......@@ -638,7 +638,7 @@
See Documentation/admin-guide/serial-console.rst for more
information. See
Documentation/networking/netconsole.txt for an
Documentation/networking/netconsole.rst for an
alternative.
uart[8250],io,<addr>[,options]
......
......@@ -54,7 +54,7 @@ You will need to create a new device to use ``/dev/console``. The official
``/dev/console`` is now character device 5,1.
(You can also use a network device as a console. See
``Documentation/networking/netconsole.txt`` for information on that.)
``Documentation/networking/netconsole.rst`` for information on that.)
Here's an example that will use ``/dev/ttyS1`` (COM2) as the console.
Replace the sample values as needed.
......
......@@ -80,6 +80,7 @@ Contents:
mac80211-injection
mpls-sysctl
multiqueue
netconsole
.. only:: subproject and html
......
.. SPDX-License-Identifier: GPL-2.0
==========
Netconsole
==========
started by Ingo Molnar <mingo@redhat.com>, 2001.09.17
2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003
IPv6 support by Cong Wang <xiyou.wangcong@gmail.com>, Jan 1 2013
Extended console support by Tejun Heo <tj@kernel.org>, May 1 2015
Please send bug reports to Matt Mackall <mpm@selenic.com>
......@@ -23,34 +32,34 @@ Sender and receiver configuration:
==================================
It takes a string configuration parameter "netconsole" in the
following format:
following format::
netconsole=[+][src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
where
+ if present, enable extended console support
src-port source for UDP packets (defaults to 6665)
src-ip source IP to use (interface address)
dev network interface (eth0)
tgt-port port for logging agent (6666)
tgt-ip IP address for logging agent
tgt-macaddr ethernet MAC address for logging agent (broadcast)
+ if present, enable extended console support
src-port source for UDP packets (defaults to 6665)
src-ip source IP to use (interface address)
dev network interface (eth0)
tgt-port port for logging agent (6666)
tgt-ip IP address for logging agent
tgt-macaddr ethernet MAC address for logging agent (broadcast)
Examples:
Examples::
linux netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
or
or::
insmod netconsole netconsole=@/,@10.0.0.2/
or using IPv6
or using IPv6::
insmod netconsole netconsole=@/,@fd00:1:2:3::1/
It also supports logging to multiple remote agents by specifying
parameters for the multiple agents separated by semicolons and the
complete string enclosed in "quotes", thusly:
complete string enclosed in "quotes", thusly::
modprobe netconsole netconsole="@/,@10.0.0.2/;@/eth1,6892@10.0.0.3/"
......@@ -67,14 +76,19 @@ for example:
On distributions using a BSD-based netcat version (e.g. Fedora,
openSUSE and Ubuntu) the listening port must be specified without
the -p switch:
the -p switch::
nc -u -l -p <port>' / 'nc -u -l <port>
or::
'nc -u -l -p <port>' / 'nc -u -l <port>' or
'netcat -u -l -p <port>' / 'netcat -u -l <port>'
netcat -u -l -p <port>' / 'netcat -u -l <port>
3) socat
'socat udp-recv:<port> -'
::
socat udp-recv:<port> -
Dynamic reconfiguration:
========================
......@@ -92,7 +106,7 @@ netconsole module (or kernel, if netconsole is built-in).
Some examples follow (where configfs is mounted at the /sys/kernel/config
mountpoint).
To add a remote logging target (target names can be arbitrary):
To add a remote logging target (target names can be arbitrary)::
cd /sys/kernel/config/netconsole/
mkdir target1
......@@ -102,12 +116,13 @@ above) and are disabled by default -- they must first be enabled by writing
"1" to the "enabled" attribute (usually after setting parameters accordingly)
as described below.
To remove a target:
To remove a target::
rmdir /sys/kernel/config/netconsole/othertarget/
The interface exposes these parameters of a netconsole target to userspace:
============== ================================= ============
enabled Is this target currently enabled? (read-write)
extended Extended mode enabled (read-write)
dev_name Local network interface name (read-write)
......@@ -117,12 +132,13 @@ The interface exposes these parameters of a netconsole target to userspace:
remote_ip Remote agent's IP address (read-write)
local_mac Local interface's MAC address (read-only)
remote_mac Remote agent's MAC address (read-write)
============== ================================= ============
The "enabled" attribute is also used to control whether the parameters of
a target can be updated or not -- you can modify the parameters of only
disabled targets (i.e. if "enabled" is 0).
To update a target's parameters:
To update a target's parameters::
cat enabled # check if enabled is 1
echo 0 > enabled # disable the target (if required)
......@@ -140,12 +156,12 @@ Extended console:
If '+' is prefixed to the configuration line or "extended" config file
is set to 1, extended console support is enabled. An example boot
param follows.
param follows::
linux netconsole=+4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
Log messages are transmitted with extended metadata header in the
following format which is the same as /dev/kmsg.
following format which is the same as /dev/kmsg::
<level>,<sequnum>,<timestamp>,<contflag>;<message text>
......@@ -155,12 +171,12 @@ newline is used as the delimeter.
If a message doesn't fit in certain number of bytes (currently 1000),
the message is split into multiple fragments by netconsole. These
fragments are transmitted with "ncfrag" header field added.
fragments are transmitted with "ncfrag" header field added::
ncfrag=<byte-offset>/<total-bytes>
For example, assuming a lot smaller chunk size, a message "the first
chunk, the 2nd chunk." may be split as follows.
chunk, the 2nd chunk." may be split as follows::
6,416,1758426,-,ncfrag=0/31;the first chunk,
6,416,1758426,-,ncfrag=16/31; the 2nd chunk.
......@@ -168,39 +184,52 @@ chunk, the 2nd chunk." may be split as follows.
Miscellaneous notes:
====================
WARNING: the default target ethernet setting uses the broadcast
ethernet address to send packets, which can cause increased load on
other systems on the same ethernet segment.
.. Warning::
the default target ethernet setting uses the broadcast
ethernet address to send packets, which can cause increased load on
other systems on the same ethernet segment.
.. Tip::
some LAN switches may be configured to suppress ethernet broadcasts
so it is advised to explicitly specify the remote agents' MAC addresses
from the config parameters passed to netconsole.
.. Tip::
to find out the MAC address of, say, 10.0.0.2, you may try using::
ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2
TIP: some LAN switches may be configured to suppress ethernet broadcasts
so it is advised to explicitly specify the remote agents' MAC addresses
from the config parameters passed to netconsole.
.. Tip::
TIP: to find out the MAC address of, say, 10.0.0.2, you may try using:
in case the remote logging agent is on a separate LAN subnet than
the sender, it is suggested to try specifying the MAC address of the
default gateway (you may use /sbin/route -n to find it out) as the
remote MAC address instead.
ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2
.. note::
TIP: in case the remote logging agent is on a separate LAN subnet than
the sender, it is suggested to try specifying the MAC address of the
default gateway (you may use /sbin/route -n to find it out) as the
remote MAC address instead.
the network device (eth1 in the above case) can run any kind
of other network traffic, netconsole is not intrusive. Netconsole
might cause slight delays in other traffic if the volume of kernel
messages is high, but should have no other impact.
NOTE: the network device (eth1 in the above case) can run any kind
of other network traffic, netconsole is not intrusive. Netconsole
might cause slight delays in other traffic if the volume of kernel
messages is high, but should have no other impact.
.. note::
NOTE: if you find that the remote logging agent is not receiving or
printing all messages from the sender, it is likely that you have set
the "console_loglevel" parameter (on the sender) to only send high
priority messages to the console. You can change this at runtime using:
if you find that the remote logging agent is not receiving or
printing all messages from the sender, it is likely that you have set
the "console_loglevel" parameter (on the sender) to only send high
priority messages to the console. You can change this at runtime using::
dmesg -n 8
dmesg -n 8
or by specifying "debug" on the kernel command line at boot, to send
all kernel messages to the console. A specific value for this parameter
can also be set using the "loglevel" kernel boot option. See the
dmesg(8) man page and Documentation/admin-guide/kernel-parameters.rst for details.
or by specifying "debug" on the kernel command line at boot, to send
all kernel messages to the console. A specific value for this parameter
can also be set using the "loglevel" kernel boot option. See the
dmesg(8) man page and Documentation/admin-guide/kernel-parameters.rst
for details.
Netconsole was designed to be as instantaneous as possible, to
enable the logging of even the most critical kernel bugs. It works
......
......@@ -302,7 +302,7 @@ config NETCONSOLE
tristate "Network console logging support"
---help---
If you want to log kernel messages over the network, enable this.
See <file:Documentation/networking/netconsole.txt> for details.
See <file:Documentation/networking/netconsole.rst> for details.
config NETCONSOLE_DYNAMIC
bool "Dynamic reconfiguration of logging targets"
......@@ -312,7 +312,7 @@ config NETCONSOLE_DYNAMIC
This option enables the ability to dynamically reconfigure target
parameters (interface, IP addresses, port numbers, MAC addresses)
at runtime through a userspace interface exported using configfs.
See <file:Documentation/networking/netconsole.txt> for details.
See <file:Documentation/networking/netconsole.rst> for details.
config NETPOLL
def_bool NETCONSOLE
......
......@@ -1150,7 +1150,7 @@ static irqreturn_t gelic_card_interrupt(int irq, void *ptr)
* gelic_net_poll_controller - artificial interrupt for netconsole etc.
* @netdev: interface device structure
*
* see Documentation/networking/netconsole.txt
* see Documentation/networking/netconsole.rst
*/
void gelic_net_poll_controller(struct net_device *netdev)
{
......
......@@ -1615,7 +1615,7 @@ spider_net_interrupt(int irq, void *ptr)
* spider_net_poll_controller - artificial interrupt for netconsole etc.
* @netdev: interface device structure
*
* see Documentation/networking/netconsole.txt
* see Documentation/networking/netconsole.rst
*/
static void
spider_net_poll_controller(struct net_device *netdev)
......
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