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T6456: Convert "monitor traffic" to modern op-mode wrapper
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The old "monitor traffic" definition had misaligned arguments under the verbose node
and manually offered the same parameter keyword in multiple positions to emulate
flexible parameters.

I've wrapped tcpdump for op-mode and replicated the "varargs" style from mtr.py/mtr.xml.in
to present a few more parameters in a more flexible manner.

Changes to the Makefile were required for recursive varargs lookup.
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talmakion committed Jun 11, 2024
1 parent dd813e5 commit e748592
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Showing 3 changed files with 175 additions and 48 deletions.
3 changes: 2 additions & 1 deletion Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -61,12 +61,13 @@ op_mode_definitions: $(op_xml_obj)
rm -f $(OP_TMPL_DIR)/clear/node.def
rm -f $(OP_TMPL_DIR)/delete/node.def

# XXX: ping, traceroute and mtr must be able to recursivly call themselves as the
# XXX: tcpdump, ping, traceroute and mtr must be able to recursivly call themselves as the
# options are provided from the scripts themselves
ln -s ../node.tag $(OP_TMPL_DIR)/ping/node.tag/node.tag/
ln -s ../node.tag $(OP_TMPL_DIR)/traceroute/node.tag/node.tag/
ln -s ../node.tag $(OP_TMPL_DIR)/mtr/node.tag/node.tag/
ln -s ../node.tag $(OP_TMPL_DIR)/monitor/traceroute/node.tag/node.tag/
ln -s ../node.tag $(OP_TMPL_DIR)/monitor/traffic/interface/node.tag/node.tag/

# XXX: test if there are empty node.def files - this is not allowed as these
# could mask help strings or mandatory priority statements
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55 changes: 8 additions & 47 deletions op-mode-definitions/traffic-dump.xml.in
Original file line number Diff line number Diff line change
Expand Up @@ -8,62 +8,23 @@
</properties>
<children>
<tagNode name="interface">
<command>sudo tcpdump -i $4</command>
<command>${vyos_op_scripts_dir}/tcpdump.py $4</command>
<properties>
<help>Monitor traffic dump from an interface</help>
<completionHelp>
<script>${vyos_completion_dir}/list_dumpable_interfaces.py</script>
</completionHelp>
</properties>
<children>
<node name="verbose">
<command>sudo tcpdump -vvv -ne -i $4</command>
<leafNode name="node.tag">
<properties>
<help>Provide more detailed packets for each monitored traffic</help>
<help>Traffic capture options</help>
<completionHelp>
<script>${vyos_op_scripts_dir}/tcpdump.py --get-options-nested "${COMP_WORDS[@]}"</script>
</completionHelp>
</properties>
<children>
<tagNode name="filter">
<command>sudo tcpdump -vvv -ne -i $4 "${@:6}"</command>
<properties>
<help>Monitor traffic matching filter conditions</help>
</properties>
</tagNode>
<tagNode name="save">
<command>sudo tcpdump -vvv -ne -i $4 -w $6</command>
<properties>
<help>Save traffic dump from an interface to a file</help>
</properties>
<children>
<tagNode name="filter">
<command>sudo tcpdump -vvv -ne -i $4 -w $6 "${@:8}"</command>
<properties>
<help>Save a dump of traffic matching filter conditions to a file</help>
</properties>
</tagNode>
</children>
</tagNode>
</children>
</node>
<tagNode name="filter">
<command>sudo tcpdump -n -i $4 "${@:6}"</command>
<properties>
<help>Monitor traffic matching filter conditions</help>
</properties>
</tagNode>
<tagNode name="save">
<command>sudo tcpdump -n -i $4 -w $6</command>
<properties>
<help>Save traffic dump from an interface to a file</help>
</properties>
<children>
<tagNode name="filter">
<command>sudo tcpdump -n -i $4 -w $6 "${@:8}"</command>
<properties>
<help>Save a dump of traffic matching filter conditions to a file</help>
</properties>
</tagNode>
</children>
</tagNode>
<command>${vyos_op_scripts_dir}/tcpdump.py "${@:4}"</command>
</leafNode>
</children>
</tagNode>
</children>
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165 changes: 165 additions & 0 deletions src/op_mode/tcpdump.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,165 @@
#! /usr/bin/env python3

# Copyright (C) 2024 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

import sys

from vyos.utils.process import call

options = {
'dump': {
'cmd': '{command} -A',
'type': 'noarg',
'help': 'Print each packet (minus its link level header) in ASCII.'
},
'hexdump': {
'cmd': '{command} -X',
'type': 'noarg',
'help': 'Print each packet (minus its link level header) in both hex and ASCII.'
},
'filter': {
'cmd': '{command} \'{value}\'',
'type': '<pcap-filter>',
'help': 'Match traffic for capture and display with a pcap-filter expression.'
},
'numeric': {
'cmd': '{command} -nn',
'type': 'noarg',
'help': 'Do not attempt to resolve addresses, protocols or services to names.'
},
'save': {
'cmd': '{command} -w {value}',
'type': '<file>',
'help': 'Write captured raw packets to <file> rather than parsing or printing them out.'
},
'verbose': {
'cmd': '{command} -vvv -ne',
'type': 'noarg',
'help': 'Parse packets with increased detail output, including link-level headers and extended decoding protocol sanity checks.'
},
}

tcpdump = 'sudo /usr/bin/tcpdump'

class List(list):
def first(self):
return self.pop(0) if self else ''

def last(self):
return self.pop() if self else ''

def prepend(self, value):
self.insert(0, value)


def completion_failure(option: str) -> None:
"""
Shows failure message after TAB when option is wrong
:param option: failure option
:type str:
"""
sys.stderr.write('\n\n Invalid option: {}\n\n'.format(option))
sys.stdout.write('<nocomps>')
sys.exit(1)


def expansion_failure(option, completions):
reason = 'Ambiguous' if completions else 'Invalid'
sys.stderr.write(
'\n\n {} command: {} [{}]\n\n'.format(reason, ' '.join(sys.argv),
option))
if completions:
sys.stderr.write(' Possible completions:\n ')
sys.stderr.write('\n '.join(completions))
sys.stderr.write('\n')
sys.stdout.write('<nocomps>')
sys.exit(1)


def complete(prefix):
return [o for o in options if o.startswith(prefix)]


def convert(command, args):
while args:
shortname = args.first()
longnames = complete(shortname)
if len(longnames) != 1:
expansion_failure(shortname, longnames)
longname = longnames[0]
if options[longname]['type'] == 'noarg':
command = options[longname]['cmd'].format(
command=command, value='')
elif not args:
sys.exit(f'monitor traffic: missing argument for {longname} option')
else:
command = options[longname]['cmd'].format(
command=command, value=args.first())
return command


if __name__ == '__main__':
args = List(sys.argv[1:])
ifname = args.first()

# Slightly simplified & tweaked version of the code from mtr.py - it may be
# worthwhile to combine and centralise this in a common module.
if ifname == '--get-options-nested':
args.first() # pop monitor
args.first() # pop traffic
args.first() # pop interface
args.first() # pop <ifname>
usedoptionslist = []
while args:
option = args.first() # pop option
matched = complete(option) # get option parameters
usedoptionslist.append(option) # list of used options
# Select options
if not args:
# remove from Possible completions used options
for o in usedoptionslist:
if o in matched:
matched.remove(o)
if not matched:
sys.stdout.write('<nocomps>')
else:
sys.stdout.write(' '.join(matched))
sys.exit(0)

if len(matched) > 1:
sys.stdout.write(' '.join(matched))
sys.exit(0)
# If option doesn't have value
if matched:
if options[matched[0]]['type'] == 'noarg':
continue
else:
# Unexpected option
completion_failure(option)

value = args.first() # pop option's value
if not args:
matched = complete(option)
helplines = options[matched[0]]['type']
# Run helpfunction to get list of possible values
if 'helpfunction' in options[matched[0]]:
result = options[matched[0]]['helpfunction']()
if result:
helplines = '\n' + ' '.join(result)
sys.stdout.write(helplines)
sys.exit(0)

command = convert(tcpdump, args)
call(f'{command} -i {ifname}')

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