Merge pull request #3601 from talmakion/bugfix/T6456

T6456: Convert "monitor traffic" to modern op-mode wrapper

1 files changed, 165 insertions, 0 deletions

diff --git a/src/op_mode/tcpdump.py b/src/op_mode/tcpdump.py
new file mode 100644
index 000000000..607b59603
--- /dev/null
+++ b/src/op_mode/tcpdump.py
@@ -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}')