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From: Matthew Wood <thepacketgeek@gmail.com>
To: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: leitao@debian.org,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH net-next v1 0/8] netconsole: Add userdata append support
Date: Wed, 24 Jan 2024 09:46:58 -0800
Message-ID: <20240124174711.1906102-1-thepacketgeek@gmail.com>
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Add the ability to add custom userdata to every outbound netconsole message
as a collection of key/value pairs, allowing users to add metadata to every
netconsole message which can be used for  for tagging, filtering, and
aggregating log messages.

In a previous patch series the ability to prepend the uname release was
added towards the goals above. This patch series builds on that
idea to allow any userdata, keyed by a user provided name, to be
included in netconsole messages.

If CONFIG_NETCONSOLE_DYNAMIC is enabled an additional userdata
directory will be presented in the netconsole configfs tree, allowing
the addition of userdata entries.

    /sys/kernel/config/netconsole/
			<target>/
				enabled
				release
				dev_name
				local_port
				remote_port
				local_ip
				remote_ip
				local_mac
				remote_mac
				userdata/
					<key>/
						value
					<key>/
						value
          ...

Testing for this series is as follows:

Build every patch without CONFIG_NETCONSOLE_DYNAMIC, and also built
with CONFIG_NETCONSOLE_DYNAMIC enabled for every patch after the config
option was added

Test Userdata configfs

    # Adding userdata
    cd /sys/kernel/config/netconsole/ && mkdir cmdline0 && cd cmdline0
    mkdir userdata/release && echo hotfix1 > userdata/release/value
    preview=3D$(for f in `ls userdata`; do echo $f=3D$(cat userdata/$f/valu=
e); done)
    [[ "$preview" =3D=3D $'release=3Dhotfix1' ]] && echo pass || echo fail
    mkdir userdata/testing && echo something > userdata/testing/value
    preview=3D$(for f in `ls userdata`; do echo $f=3D$(cat userdata/$f/valu=
e); done)
    [[ "$preview" =3D=3D $'release=3Dhotfix1\ntesting=3Dsomething' ]] && ec=
ho pass || echo fail
    #
    # Removing Userdata
    rmdir userdata/testing
    preview=3D$(for f in `ls userdata`; do echo $f=3D$(cat userdata/$f/valu=
e); done)
    [[ "$preview" =3D=3D $'release=3Dhotfix1' ]] && echo pass || echo fail
    rmdir userdata/release
    [[ `cat userdata/complete` =3D=3D $'release=3Dhotfix1' ]] && echo pass =
|| echo fail
    #
    # Adding userdata key with too large of 6.7.0-rc8-virtme,12,481,1795410=
4,-directory name [<54 chars]
    mkdir userdata/testing12345678901234567890123456789012345678901234567890
    [[ $? =3D=3D 1 ]] && echo pass || echo fail
    #
    # Adding userdata value with too large of value [<200 chars]
    mkdir userdata/testing
    echo `for i in {1..201};do printf "%s" "v";done` > userdata/testing/val=
ue
    [[ $? =3D=3D 1 ]] && echo pass || echo fail
    rmdir userdata/testing

- Output:

    pass
    pass
    pass
    pass
    pass
    mkdir: cannot create directory =E2=80=98cmdline0/userdata/testing123456=
78901234567890123456789012345678901234567890=E2=80=99: File name too long
    pass
    bash: echo: write error: Message too long
    pass

Test netconsole messages (w/ msg fragmentation)

    echo `for i in {1..996};do printf "%s" "v";done` > /dev/kmsg

- Output:

    6.7.0-rc8-virtme,12,484,84321212,-,ncfrag=3D0/997;vvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv6.7.0-rc8-virtme,12,484,84321212,-,ncfrag=3D=
952/997;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Test empty userdatum

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/empty
    echo test > /dev/kmsg
    rmdir cmdline0/userdata/empty

- Output:

Test netconsole messages (w/o userdata fragmentation)

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/release && echo hotfix1 > cmdline0/userdata/rel=
ease/value
    mkdir cmdline0/userdata/testing && echo something > cmdline0/userdata/t=
esting/value
    echo test > /dev/kmsg
    rmdir cmdline0/userdata/release
    rmdir cmdline0/userdata/testing

- Output:
    6.7.0-rc8-virtme,12,500,1646292204,-;test
    release=3Dhotfix1
    testing=3Dsomething

Test netconsole messages (w/ long body fragmentation)
    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/release && echo hotfix1 > cmdline0/userdata/rel=
ease/value
    mkdir cmdline0/userdata/testing && echo something > cmdline0/userdata/t=
esting/value
    echo `for i in {1..996};do printf "%s" "v";done` > /dev/kmsg
    rmdir cmdline0/userdata/release
    rmdir cmdline0/userdata/testing

- Output:
    6.7.0-rc8-virtme,12,486,156664417,-,ncfrag=3D0/1031;vvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv=
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv6.7.0-rc8-virtme,12,486,156664417,-,ncfrag=
=3D950/1031;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    release=3Dhotfix1
    testing=3Dsomething

Test netconsole messages (w/ long userdata fragmentation)

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    LOREM=3D"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut"
    for i in {0..5}; do mkdir cmdline0/userdata/value${i} && echo ${LOREM} =
> cmdline0/userdata/value${i}/value; done
    echo test > /dev/kmsg
    for i in {0..5}; do rmdir cmdline0/userdata/value${i}; done

- Output:
    6.7.0-rc8-virtme,12,487,221763007,-,ncfrag=3D0/1241;test
    value0=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value1=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value2=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value3=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value4=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magn6.7.0-rc8-virtme,12,487=
,221763007,-,ncfrag=3D950/1241;a aliqua. Ut enim ad minim veniam, quis nost=
rud exercitation ullamco laboris nisi ut
    value5=3DLorem ipsum dolor sit amet, consectetur adipiscing elit, sed d=
o eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad mi=
nim veniam, quis nostrud exercitation ullamco laboris nisi ut


Matthew Wood (8):
  net: netconsole: cleanup formatting lints
  net: netconsole: move netconsole_target config_item to config_group
  net: netconsole: move newline trimming to function
  net: netconsole: add docs for appending netconsole user data
  net: netconsole: add a userdata config_group member to
    netconsole_target
  net: netconsole: cache userdata formatted string in netconsole_target
  net: netconsole: append userdata to netconsole messages
  net: netconsole: append userdata to fragmented netconsole messages

 Documentation/networking/netconsole.rst |  68 +++++
 drivers/net/netconsole.c                | 355 ++++++++++++++++++++----
 2 files changed, 369 insertions(+), 54 deletions(-)

--
2.43.0