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: Mauro Carvalho Chehab <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/admin-guide/kernel-parameters.txt

···
 
 			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]

Documentation/admin-guide/serial-console.rst

···
 ``/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.

Documentation/networking/index.rst

···
    mac80211-injection
    mpls-sysctl
    multiqueue
+   netconsole
 
 .. only::  subproject and html
 

Documentation/networking/netconsole.txt Documentation/networking/netconsole.rst

···
+.. SPDX-License-Identifier: GPL-2.0
+
+==========
+Netconsole
+==========
+
 
 started by Ingo Molnar <[e-mail]>, 2001.09.17
+
 2.6 port and netpoll api by Matt Mackall <[e-mail]>, Sep 9 2003
+
 IPv6 support by Cong Wang <[e-mail]>, Jan 1 2013
+
 Extended console support by Tejun Heo <[e-mail]>, May 1 2015
 
 Please send bug reports to Matt Mackall <[e-mail]>
···
 ==================================
 
 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/"
 
···
 
    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
-   'netcat -u -l -p <port>' / 'netcat -u -l <port>'
+	nc -u -l -p <port>' / 'nc -u -l <port>
+
+    or::
+
+	netcat -u -l -p <port>' / 'netcat -u -l <port>
 
 3) socat
 
-   'socat udp-recv:<port> -'
+::
+
+   socat udp-recv:<port> -
 
 Dynamic reconfiguration:
 ========================
···
 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
···
 "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)
···
 	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)
···
 
 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>
 
···
 
 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.
···
 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::
 
-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.
+   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: to find out the MAC address of, say, 10.0.0.2, you may try using:
+.. Tip::
 
- ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2
+   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: 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.
+.. Tip::
 
-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.
+   to find out the MAC address of, say, 10.0.0.2, you may try using::
 
-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:
+	ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2
 
- dmesg -n 8
+.. Tip::
 
-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.
+   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.
+
+.. 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::
+
+   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
+
+   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

drivers/net/Kconfig

···
 	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"
···
 	  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

drivers/net/ethernet/toshiba/ps3_gelic_net.c

···
  * 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)
 {

drivers/net/ethernet/toshiba/spider_net.c

···
  * 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)