libs/sys/luasrc/sys/iptparser.lua

   1 --[[
   2
   3 Iptables parser and query library
   4 (c) 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net>
   5 (c) 2008 Steven Barth <steven@midlink.org>
   6
   7 Licensed under the Apache License, Version 2.0 (the "License");
   8 you may not use this file except in compliance with the License.
   9 You may obtain a copy of the License at
  10
  11         http://www.apache.org/licenses/LICENSE-2.0
  12
  13 $Id$
  14
  15 ]]--
  16
  17 local luci  = {}
  18 luci.util   = require "luci.util"
  19 luci.sys    = require "luci.sys"
  20 luci.ip     = require "luci.ip"
  21
  22 local tonumber, ipairs = tonumber, ipairs
  23
  24 --- LuCI iptables parser and query library
  25 -- @cstyle      instance
  26 module("luci.sys.iptparser")
  27
  28 --- Create a new iptables parser object.
  29 -- @class       function
  30 -- @name        IptParser
  31 -- @return      IptParser instance
  32 IptParser = luci.util.class()
  33
  34 function IptParser.__init__( self, ... )
  35         self._rules = { }
  36         self._chain = nil
  37         self:_parse_rules()
  38 end
  39
  40 --- Find all firewall rules that match the given criteria. Expects a table with
  41 -- search criteria as only argument. If args is nil or an empty table then all
  42 -- rules will be returned.
  43 --
  44 -- The following keys in the args table are recognized:
  45 -- <ul>
  46 --  <li> table           - Match rules that are located within the given table
  47 --  <li> chain           - Match rules that are located within the given chain
  48 --  <li> target          - Match rules with the given target
  49 --  <li> protocol        - Match rules that match the given protocol, rules with
  50 --                                              protocol "all" are always matched
  51 --  <li> source          - Match rules with the given source, rules with source
  52 --                                              "0.0.0.0/0" are always matched
  53 --  <li> destination - Match rules with the given destination, rules with
  54 --                                              destination "0.0.0.0/0" are always matched
  55 --  <li> inputif         - Match rules with the given input interface, rules
  56 --                                              with input      interface "*" (=all) are always matched
  57 --  <li> outputif        - Match rules with the given output interface, rules
  58 --                                              with output     interface "*" (=all) are always matched
  59 --  <li> flags           - Match rules that match the given flags, current
  60 --                                              supported values are "-f" (--fragment)
  61 --                                              and "!f" (! --fragment)
  62 --  <li> options         - Match rules containing all given options
  63 -- </ul>
  64 -- The return value is a list of tables representing the matched rules.
  65 -- Each rule table contains the following fields:
  66 -- <ul>
  67 --  <li> index           - The index number of the rule
  68 --  <li> table           - The table where the rule is located, can be one
  69 --                                              of "filter", "nat" or "mangle"
  70 --  <li> chain           - The chain where the rule is located, e.g. "INPUT"
  71 --                                              or "postrouting_wan"
  72 --  <li> target          - The rule target, e.g. "REJECT" or "DROP"
  73 --  <li> protocol               The matching protocols, e.g. "all" or "tcp"
  74 --  <li> flags           - Special rule options ("--", "-f" or "!f")
  75 --  <li> inputif         - Input interface of the rule, e.g. "eth0.0"
  76 --                                              or "*" for all interfaces
  77 --  <li> outputif        - Output interface of the rule,e.g. "eth0.0"
  78 --                                              or "*" for all interfaces
  79 --  <li> source          - The source ip range, e.g. "0.0.0.0/0"
  80 --  <li> destination - The destination ip range, e.g. "0.0.0.0/0"
  81 --  <li> options         - A list of specific options of the rule,
  82 --                                              e.g. { "reject-with", "tcp-reset" }
  83 --  <li> packets         - The number of packets matched by the rule
  84 --  <li> bytes           - The number of total bytes matched by the rule
  85 -- </ul>
  86 -- Example:
  87 -- <pre>
  88 -- ip = luci.sys.iptparser.IptParser()
  89 -- result = ip.find( {
  90 --      target="REJECT",
  91 --      protocol="tcp",
  92 --      options={ "reject-with", "tcp-reset" }
  93 -- } )
  94 -- </pre>
  95 -- This will match all rules with target "-j REJECT",
  96 -- protocol "-p tcp" (or "-p all")
  97 -- and the option "--reject-with tcp-reset".
  98 -- @params args         Table containing the search arguments (optional)
  99 -- @return                      Table of matching rule tables
 100 function IptParser.find( self, args )
 101
 102         local args = args or { }
 103         local rv   = { }
 104
 105         args.source      = args.source      and luci.ip.IPv4(args.source)
 106         args.destination = args.destination and luci.ip.IPv4(args.destination)
 107
 108         for i, rule in ipairs(self._rules) do
 109                 local match = true
 110
 111                 -- match table
 112                 if not ( not args.table or args.table == rule.table ) then
 113                         match = false
 114                 end
 115
 116                 -- match chain
 117                 if not ( match == true and (
 118                         not args.chain or args.chain == rule.chain
 119                 ) ) then
 120                         match = false
 121                 end
 122
 123                 -- match target
 124                 if not ( match == true and (
 125                         not args.target or args.target:upper() == rule.target
 126                 ) ) then
 127                         match = false
 128                 end
 129
 130                 -- match protocol
 131                 if not ( match == true and (
 132                         not args.protocol or rule.protocol == "all" or
 133                         args.protocol:lower() == rule.protocol
 134                 ) ) then
 135                         match = false
 136                 end
 137
 138                 -- match source
 139                 if not ( match == true and (
 140                         not args.source or rule.source == "0.0.0.0/0" or
 141                         luci.ip.IPv4(rule.source):contains(args.source)
 142                 ) ) then
 143                         match = false
 144                 end
 145
 146                 -- match destination
 147                 if not ( match == true and (
 148                         not args.destination or rule.destination == "0.0.0.0/0" or
 149                         luci.ip.IPv4(rule.destination):contains(args.destination)
 150                 ) ) then
 151                         match = false
 152                 end
 153
 154                 -- match input interface
 155                 if not ( match == true and (
 156                         not args.inputif or rule.inputif == "*" or
 157                         args.inputif == rule.inputif
 158                 ) ) then
 159                         match = false
 160                 end
 161
 162                 -- match output interface
 163                 if not ( match == true and (
 164                         not args.outputif or rule.outputif == "*" or
 165                         args.outputif == rule.outputif
 166                 ) ) then
 167                         match = false
 168                 end
 169
 170                 -- match flags (the "opt" column)
 171                 if not ( match == true and (
 172                         not args.flags or rule.flags == args.flags
 173                 ) ) then
 174                         match = false
 175                 end
 176
 177                 -- match specific options
 178                 if not ( match == true and (
 179                         not args.options or
 180                         self:_match_options( rule.options, args.options )
 181                 ) ) then
 182                         match = false
 183                 end
 184
 185                 -- insert match
 186                 if match == true then
 187                         rv[#rv+1] = rule
 188                 end
 189         end
 190
 191         return rv
 192 end
 193
 194
 195 --- Rebuild the internal lookup table, for example when rules have changed
 196 -- through external commands.
 197 -- @return      nothing
 198 function IptParser.resync( self )
 199         self._rules = { }
 200         self._chain = nil
 201         self:_parse_rules()
 202 end
 203
 204
 205 -- [internal] Parse iptables output from all tables.
 206 function IptParser._parse_rules( self )
 207
 208         for i, tbl in ipairs({ "filter", "nat", "mangle" }) do
 209
 210                 for i, rule in ipairs(luci.util.execl("iptables -t " .. tbl .. " --line-numbers -nxvL")) do
 211
 212                         if rule:find( "Chain " ) == 1 then
 213
 214                                 self._chain = rule:gsub("Chain ([^%s]*) .*", "%1")
 215
 216                         else
 217                                 if rule:find("%d") == 1 then
 218
 219                                         local rule_partmays   = luci.util.split( rule, "%s+", nil, true )
 220                                         local rule_details = { }
 221
 222                                         rule_details["table"]       = tbl
 223                                         rule_details["chain"]       = self._chain
 224                                         rule_details["index"]       = tonumber(rule_parts[1])
 225                                         rule_details["packets"]     = tonumber(rule_parts[2])
 226                                         rule_details["bytes"]       = tonumber(rule_parts[3])
 227                                         rule_details["target"]      = rule_parts[4]
 228                                         rule_details["protocol"]    = rule_parts[5]
 229                                         rule_details["flags"]       = rule_parts[6]
 230                                         rule_details["inputif"]     = rule_parts[7]
 231                                         rule_details["outputif"]    = rule_parts[8]
 232                                         rule_details["source"]      = rule_parts[9]
 233                                         rule_details["destination"] = rule_parts[10]
 234                                         rule_details["options"]     = { }
 235
 236                                         for i = 11, #rule_parts - 1 do
 237                                                 rule_details["options"][i-10] = rule_parts[i]
 238                                         end
 239
 240                                         self._rules[#self._rules+1] = rule_details
 241                                 end
 242                         end
 243                 end
 244         end
 245
 246         self._chain = nil
 247 end
 248
 249
 250 -- [internal] Return true if optlist1 contains all elements of optlist 2.
 251 --            Return false in all other cases.
 252 function IptParser._match_options( self, o1, o2 )
 253
 254         -- construct a hashtable of first options list to speed up lookups
 255         local oh = { }
 256         for i, opt in ipairs( o1 ) do oh[opt] = true end
 257
 258         -- iterate over second options list
 259         -- each string in o2 must be also present in o1
 260         -- if o2 contains a string which is not found in o1 then return false
 261         for i, opt in ipairs( o2 ) do
 262                 if not oh[opt] then
 263                         return false
 264                 end
 265         end
 266
 267         return true
 268 end