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authorChristian Poessinger <christian@poessinger.com>2019-04-21 13:19:12 +0200
committerChristian Poessinger <christian@poessinger.com>2019-04-21 13:21:12 +0200
commit7d024a324412f4902b9ba212277901bbbe2f949c (patch)
tree3cdb6d4dfd8f2ee30cbcb21aa3b1a3f25016600f /src
parent0a0f32e9a770b6b3f50295e10b593358a60813d5 (diff)
downloadvyos-1x-7d024a324412f4902b9ba212277901bbbe2f949c.tar.gz
vyos-1x-7d024a324412f4902b9ba212277901bbbe2f949c.zip
[firewall] T314: add firewall options for MSS clamping
* clamp MSS IPv4 set firewall options interface pppoe0 adjust-mss '1452' * clamp MSS IPv6 set firewall options interface pppoe0 adjust-mss6 '1452' * disable entire rule set firewall options interface pppoe0 disable Output ------ $ sudo iptables-save -t mangle # Generated by iptables-save v1.4.21 on Sun Apr 21 12:56:25 2019 *mangle :PREROUTING ACCEPT [1217:439885] :INPUT ACCEPT [290:52459] :FORWARD ACCEPT [920:375774] :OUTPUT ACCEPT [301:100053] :POSTROUTING ACCEPT [1221:475827] :VYOS_FW_OPTIONS - [0:0] -A FORWARD -j VYOS_FW_OPTIONS -A VYOS_FW_OPTIONS -o pppoe0 -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 1452 COMMIT Completed on Sun Apr 21 12:56:25 2019 (cherry picked from commit 476aa4c3a561ea0ef0bf9b4c26ec8b78d18a5d02)
Diffstat (limited to 'src')
-rwxr-xr-xsrc/conf_mode/firewall_options.py142
1 files changed, 142 insertions, 0 deletions
diff --git a/src/conf_mode/firewall_options.py b/src/conf_mode/firewall_options.py
new file mode 100755
index 000000000..e2c306904
--- /dev/null
+++ b/src/conf_mode/firewall_options.py
@@ -0,0 +1,142 @@
+#!/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/>.
+#
+
+import sys
+import os
+import copy
+
+from vyos.config import Config
+from vyos import ConfigError
+
+default_config_data = {
+ 'intf_opts': [],
+ 'new_chain4': False,
+ 'new_chain6': False
+}
+
+def get_config():
+ opts = copy.deepcopy(default_config_data)
+ conf = Config()
+ if not conf.exists('firewall options'):
+ return None
+ else:
+ conf.set_level('firewall options')
+
+ # Parse configuration of each individual instance
+ if conf.exists('interface'):
+ for intf in conf.list_nodes('interface'):
+ conf.set_level('firewall options interface {0}'.format(intf))
+ config = {
+ 'intf': intf,
+ 'disabled': False,
+ 'mss4': '',
+ 'mss6': ''
+ }
+
+ # Check if individual option is disabled
+ if conf.exists('disable'):
+ config['disabled'] = True
+
+ #
+ # Get MSS value IPv4
+ #
+ if conf.exists('adjust-mss'):
+ config['mss4'] = conf.return_value('adjust-mss')
+
+ # We need a marker that a new iptables chain needs to be generated
+ if not opts['new_chain4']:
+ opts['new_chain4'] = True
+
+ #
+ # Get MSS value IPv6
+ #
+ if conf.exists('adjust-mss6'):
+ config['mss6'] = conf.return_value('adjust-mss6')
+
+ # We need a marker that a new ip6tables chain needs to be generated
+ if not opts['new_chain6']:
+ opts['new_chain6'] = True
+
+ # Append interface options to global list
+ opts['intf_opts'].append(config)
+
+ return opts
+
+def verify(tcp):
+ # syntax verification is done via cli
+ return None
+
+def apply(tcp):
+ target = 'VYOS_FW_OPTIONS'
+
+ # always cleanup iptables
+ os.system('iptables --table mangle --delete FORWARD --jump {} >&/dev/null'.format(target))
+ os.system('iptables --table mangle --flush {} >&/dev/null'.format(target))
+ os.system('iptables --table mangle --delete-chain {} >&/dev/null'.format(target))
+
+ # always cleanup ip6tables
+ os.system('ip6tables --table mangle --delete FORWARD --jump {} >&/dev/null'.format(target))
+ os.system('ip6tables --table mangle --flush {} >&/dev/null'.format(target))
+ os.system('ip6tables --table mangle --delete-chain {} >&/dev/null'.format(target))
+
+ # Setup new iptables rules
+ if tcp['new_chain4']:
+ os.system('iptables --table mangle --new-chain {} >&/dev/null'.format(target))
+ os.system('iptables --table mangle --append FORWARD --jump {} >&/dev/null'.format(target))
+
+ for opts in tcp['intf_opts']:
+ intf = opts['intf']
+ mss = opts['mss4']
+
+ # Check if this rule iis disabled
+ if opts['disabled']:
+ continue
+
+ # adjust TCP MSS per interface
+ if mss:
+ os.system('iptables --table mangle --append {} --out-interface {} --protocol tcp ' \
+ '--tcp-flags SYN,RST SYN --jump TCPMSS --set-mss {} >&/dev/null'.format(target, intf, mss))
+
+ # Setup new ip6tables rules
+ if tcp['new_chain6']:
+ os.system('ip6tables --table mangle --new-chain {} >&/dev/null'.format(target))
+ os.system('ip6tables --table mangle --append FORWARD --jump {} >&/dev/null'.format(target))
+
+ for opts in tcp['intf_opts']:
+ intf = opts['intf']
+ mss = opts['mss6']
+
+ # Check if this rule iis disabled
+ if opts['disabled']:
+ continue
+
+ # adjust TCP MSS per interface
+ if mss:
+ os.system('ip6tables --table mangle --append {} --out-interface {} --protocol tcp ' \
+ '--tcp-flags SYN,RST SYN --jump TCPMSS --set-mss {} >&/dev/null'.format(target, intf, mss))
+
+ return None
+
+if __name__ == '__main__':
+
+ try:
+ c = get_config()
+ verify(c)
+ apply(c)
+ except ConfigError as e:
+ print(e)
+ sys.exit(1)