nat: T2460: add src/op_mode/show_nat_translations.py

1 files changed, 196 insertions, 0 deletions

diff --git a/src/op_mode/show_nat_translations.py b/src/op_mode/show_nat_translations.py
new file mode 100755
index 000000000..db3d2bf0a
--- /dev/null
+++ b/src/op_mode/show_nat_translations.py
@@ -0,0 +1,196 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2018 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/>.
+
+'''
+show nat translations
+'''
+
+import os
+import sys
+import ipaddress
+import argparse
+import xmltodict
+
+from vyos.util import popen
+from vyos.util import DEVNULL
+
+conntrack = '/usr/sbin/conntrack'
+
+verbose_format = "%-20s %-18s %-20s %-18s"
+normal_format = "%-20s %-20s %-4s  %-8s %s"
+
+
+def headers(verbose, pipe):
+    if verbose:
+        return verbose_format % ('Pre-NAT src', 'Pre-NAT dst', 'Post-NAT src', 'Post-NAT dst')
+    return normal_format % ('Pre-NAT', 'Post-NAT', 'Prot', 'Timeout', 'Type' if pipe else '')
+
+
+def command(srcdest, proto, ipaddr):
+    command = f'{conntrack} -o xml -L'
+
+    if proto:
+        command += f' -p {proto}'
+
+    if srcdest == 'source':
+        command += ' -n'
+        if ipaddr:
+            command += f' --orig-src {ipaddr}'
+    if srcdest == 'destination':
+        command += ' -g'
+
+    return command
+
+
+def run(command):
+    xml, code = popen(command,stderr=DEVNULL)
+    if code:
+        sys.exit('conntrack failed')
+    return xml
+
+
+def content(xmlfile):
+    xml = ''
+    with open(xmlfile,'r') as r:
+        xml += r.read()
+    return xml
+
+
+def pipe():
+    xml = ''
+    while True:
+        line = sys.stdin.readline()
+        xml += line
+        if '</conntrack>' in line:
+            break
+
+    sys.stdin = open('/dev/tty')
+    return xml
+
+
+def process(data, stats, protocol, pipe, verbose, flowtype=''):
+    if not data:
+        return
+ 
+    parsed = xmltodict.parse(data)
+
+    print(headers(verbose, pipe))
+
+    # to help the linter to detect typos
+    ORIGINAL = 'original'
+    REPLY = 'reply'
+    INDEPENDANT = 'independent'
+    SPORT = 'sport'
+    DPORT = 'dport'
+    SRC = 'src'
+    DST = 'dst'
+
+    for rule in parsed['conntrack']['flow']:
+        src, dst, sport, dport, proto = {}, {}, {}, {}, {}
+        packet_count, byte_count = {}, {}
+        timeout, use = 0, 0
+
+        rule_type = rule.get('type', '')
+ 
+        for meta in rule['meta']:
+            # print(meta)
+            direction = meta['@direction']
+
+            if direction in (ORIGINAL, REPLY):
+                if 'layer3' in meta:
+                    l3 = meta['layer3']
+                    src[direction] = l3[SRC]
+                    dst[direction] = l3[DST]
+
+                if 'layer4' in meta:
+                    l4 = meta['layer4']
+                    sport[direction] = l4[SPORT]
+                    dport[direction] = l4[DPORT]
+                    proto[direction] = l4.get('@protoname','')
+
+                if stats and 'counters' in meta:
+                    packet_count[direction] = meta['packets']
+                    byte_count[direction] = meta['bytes']
+                continue
+
+            if direction == INDEPENDANT:
+                timeout = meta['timeout']
+                use = meta['use']
+                continue
+
+        in_src = '%s:%s' % (src[ORIGINAL], sport[ORIGINAL]) if ORIGINAL in sport else src[ORIGINAL]
+        in_dst = '%s:%s' % (dst[ORIGINAL], dport[ORIGINAL]) if ORIGINAL in dport else dst[ORIGINAL]
+
+        # inverted the the perl code !!?
+        out_dst = '%s:%s' % (dst[REPLY], dport[REPLY]) if REPLY in dport else dst[REPLY]
+        out_src = '%s:%s' % (src[REPLY], sport[REPLY]) if REPLY in sport else src[REPLY]
+
+        if flowtype == 'source':
+            v = ORIGINAL in sport and REPLY in dport
+            f = '%s:%s' % (src[ORIGINAL], sport[ORIGINAL]) if v else src[ORIGINAL]
+            t = '%s:%s' % (dst[REPLY], dport[REPLY]) if v else dst[REPLY]
+        else:
+            v = ORIGINAL in dport and REPLY in sport
+            f = '%s:%s' % (dst[ORIGINAL], dport[ORIGINAL]) if v else dst[ORIGINAL]
+            t = '%s:%s' % (src[REPLY], sport[REPLY]) if v else src[REPLY]
+
+        # Thomas: I do not believe proto should be an option
+        p = proto.get('original', '')
+        if protocol and p != protocol:
+            continue
+
+        if verbose:
+            msg = verbose_format % (in_src, in_dst, out_dst, out_src)
+            p = f'{p}: ' if p else ''
+            msg += f'\n  {p}{f} ==> {t}'
+            msg += f' timeout: {timeout}' if timeout else ''
+            msg += f' use: {use} ' if use else ''
+            msg += f' type: {rule_type}' if rule_type else ''
+            print(msg)
+        else:
+            print(normal_format % (f, t, p, timeout, rule_type if rule_type else ''))
+
+        if stats:
+            for direction in ('original', 'reply'):
+                if direction in packet_count:
+                    print('  %-8s: packets %s, bytes %s' % direction, packet_count[direction], byte_count[direction])
+
+
+def main():
+    parser = argparse.ArgumentParser(description=sys.modules[__name__].__doc__)
+    parser.add_argument('--verbose', help='provide more details about the flows', action='store_true')
+    parser.add_argument('--proto', help='filter by protocol', default='', type=str)
+    parser.add_argument('--file', help='read the conntrack xml from a file', type=str)
+    parser.add_argument('--stats', help='add usage statistics', action='store_true')
+    parser.add_argument('--type', help='NAT type (source, destination)', required=True, type=str)
+    parser.add_argument('--ipaddr', help='source ip address to filter on', type=ipaddress.ip_address)
+    parser.add_argument('--pipe', help='read conntrack xml data from stdin', action='store_true')
+
+    arg = parser.parse_args()
+
+    if arg.type not in ('source', 'destination'):
+        sys.exit('Unknown NAT type!')
+
+    if arg.pipe:
+        process(pipe(), arg.stats, arg.proto, arg.pipe, arg.verbose, arg.type)
+    elif arg.file:
+        process(content(arg.file), arg.stats, arg.proto, arg.pipe, arg.verbose, arg.type)
+    else:
+        process(run(command(arg.type, arg.proto, arg.ipaddr)), arg.stats, arg.proto, arg.pipe, arg.verbose, arg.type)
+
+
+if __name__ == '__main__':
+    main()