---

yaml
---
r: 66279
b: refs/heads/master
c: 0bcc181
h: refs/heads/master
i:
  66277: d9a4692
  66275: 6ab94d0
  66271: 75ed38a
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b5427c27173e128dda1541bd9d3b05df79af5882
+refs/heads/master: 0bcc1816188e570bde1d56a208996660f2633ae0

trunk/Documentation/networking/netconsole.txt

@@ -3,6 +3,10 @@ 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
 
 Please send bug reports to Matt Mackall <mpm@selenic.com>
+and Satyam Sharma <satyam.sharma@gmail.com>
+
+Introduction:
+=============
 
 This module logs kernel printk messages over UDP allowing debugging of
 problem where disk logging fails and serial consoles are impractical.
@@ -13,6 +17,9 @@ the specified interface as soon as possible. While this doesn't allow
 capture of early kernel panics, it does capture most of the boot
 process.
 
+Sender and receiver configuration:
+==================================
+
 It takes a string configuration parameter "netconsole" in the
 following format:
 
@@ -46,6 +53,67 @@ address.
 
 The remote host can run either 'netcat -u -l -p <port>' or syslogd.
 
+Dynamic reconfiguration:
+========================
+
+Dynamic reconfigurability is a useful addition to netconsole that enables
+remote logging targets to be dynamically added, removed, or have their
+parameters reconfigured at runtime from a configfs-based userspace interface.
+[ Note that the parameters of netconsole targets that were specified/created
+from the boot/module option are not exposed via this interface, and hence
+cannot be modified dynamically. ]
+
+To include this feature, select CONFIG_NETCONSOLE_DYNAMIC when building the
+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):
+
+ cd /sys/kernel/config/netconsole/
+ mkdir target1
+
+Note that newly created targets have default parameter values (as mentioned
+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:
+
+ 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)
+	dev_name	Local network interface name		(read-write)
+	local_port	Source UDP port to use			(read-write)
+	remote_port	Remote agent's UDP port			(read-write)
+	local_ip	Source IP address to use		(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:
+
+ cat enabled				# check if enabled is 1
+ echo 0 > enabled			# disable the target (if required)
+ echo eth2 > dev_name			# set local interface
+ echo 10.0.0.4 > remote_ip		# update some parameter
+ echo cb:a9:87:65:43:21 > remote_mac	# update more parameters
+ echo 1 > enabled			# enable target again
+
+You can also update the local interface dynamically. This is especially
+useful if you want to use interfaces that have newly come up (and may not
+have existed when netconsole was loaded / initialized).
+
+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.

trunk/drivers/net/Kconfig

@@ -3082,6 +3082,16 @@ config NETCONSOLE
 	If you want to log kernel messages over the network, enable this.
 	See <file:Documentation/networking/netconsole.txt> for details.
 
+config NETCONSOLE_DYNAMIC
+	bool "Dynamic reconfiguration of logging targets (EXPERIMENTAL)"
+	depends on NETCONSOLE && SYSFS && EXPERIMENTAL
+	select CONFIGFS_FS
+	help
+	  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.
+
 config NETPOLL
 	def_bool NETCONSOLE