modules/luci-base/luasrc/sys/iptparser.lua

   1 --[[
   2
   3 Iptables parser and query library
   4 (c) 2008-2009 Jo-Philipp Wich <jow@openwrt.org>
   5 (c) 2008-2009 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, table = tonumber, ipairs, table
  23
  24 module("luci.sys.iptparser")
  25
  26 IptParser = luci.util.class()
  27
  28 function IptParser.__init__( self, family )
  29         self._family = (tonumber(family) == 6) and 6 or 4
  30         self._rules  = { }
  31         self._chains = { }
  32
  33         if self._family == 4 then
  34                 self._nulladdr = "0.0.0.0/0"
  35                 self._tables   = { "filter", "nat", "mangle", "raw" }
  36                 self._command  = "iptables -t %s --line-numbers -nxvL"
  37         else
  38                 self._nulladdr = "::/0"
  39                 self._tables   = { "filter", "mangle", "raw" }
  40                 self._command  = "ip6tables -t %s --line-numbers -nxvL"
  41         end
  42
  43         self:_parse_rules()
  44 end
  45
  46 -- search criteria as only argument. If args is nil or an empty table then all
  47 -- rules will be returned.
  48 --
  49 -- The following keys in the args table are recognized:
  50 -- <ul>
  51 --  <li> table           - Match rules that are located within the given table
  52 --  <li> chain           - Match rules that are located within the given chain
  53 --  <li> target          - Match rules with the given target
  54 --  <li> protocol        - Match rules that match the given protocol, rules with
  55 --                                              protocol "all" are always matched
  56 --  <li> source          - Match rules with the given source, rules with source
  57 --                                              "0.0.0.0/0" (::/0) are always matched
  58 --  <li> destination - Match rules with the given destination, rules with
  59 --                                              destination "0.0.0.0/0" (::/0) are always matched
  60 --  <li> inputif         - Match rules with the given input interface, rules
  61 --                                              with input      interface "*" (=all) are always matched
  62 --  <li> outputif        - Match rules with the given output interface, rules
  63 --                                              with output     interface "*" (=all) are always matched
  64 --  <li> flags           - Match rules that match the given flags, current
  65 --                                              supported values are "-f" (--fragment)
  66 --                                              and "!f" (! --fragment)
  67 --  <li> options         - Match rules containing all given options
  68 -- </ul>
  69 -- The return value is a list of tables representing the matched rules.
  70 -- Each rule table contains the following fields:
  71 -- <ul>
  72 --  <li> index           - The index number of the rule
  73 --  <li> table           - The table where the rule is located, can be one
  74 --                                              of "filter", "nat" or "mangle"
  75 --  <li> chain           - The chain where the rule is located, e.g. "INPUT"
  76 --                                              or "postrouting_wan"
  77 --  <li> target          - The rule target, e.g. "REJECT" or "DROP"
  78 --  <li> protocol               The matching protocols, e.g. "all" or "tcp"
  79 --  <li> flags           - Special rule options ("--", "-f" or "!f")
  80 --  <li> inputif         - Input interface of the rule, e.g. "eth0.0"
  81 --                                              or "*" for all interfaces
  82 --  <li> outputif        - Output interface of the rule,e.g. "eth0.0"
  83 --                                              or "*" for all interfaces
  84 --  <li> source          - The source ip range, e.g. "0.0.0.0/0" (::/0)
  85 --  <li> destination - The destination ip range, e.g. "0.0.0.0/0" (::/0)
  86 --  <li> options         - A list of specific options of the rule,
  87 --                                              e.g. { "reject-with", "tcp-reset" }
  88 --  <li> packets         - The number of packets matched by the rule
  89 --  <li> bytes           - The number of total bytes matched by the rule
  90 -- </ul>
  91 -- Example:
  92 -- <pre>
  93 -- ip = luci.sys.iptparser.IptParser()
  94 -- result = ip.find( {
  95 --      target="REJECT",
  96 --      protocol="tcp",
  97 --      options={ "reject-with", "tcp-reset" }
  98 -- } )
  99 -- </pre>
 100 -- This will match all rules with target "-j REJECT",
 101 -- protocol "-p tcp" (or "-p all")
 102 -- and the option "--reject-with tcp-reset".
 103 function IptParser.find( self, args )
 104
 105         local args = args or { }
 106         local rv   = { }
 107
 108         args.source      = args.source      and self:_parse_addr(args.source)
 109         args.destination = args.destination and self:_parse_addr(args.destination)
 110
 111         for i, rule in ipairs(self._rules) do
 112                 local match = true
 113
 114                 -- match table
 115                 if not ( not args.table or args.table:lower() == rule.table ) then
 116                         match = false
 117                 end
 118
 119                 -- match chain
 120                 if not ( match == true and (
 121                         not args.chain or args.chain == rule.chain
 122                 ) ) then
 123                         match = false
 124                 end
 125
 126                 -- match target
 127                 if not ( match == true and (
 128                         not args.target or args.target == rule.target
 129                 ) ) then
 130                         match = false
 131                 end
 132
 133                 -- match protocol
 134                 if not ( match == true and (
 135                         not args.protocol or rule.protocol == "all" or
 136                         args.protocol:lower() == rule.protocol
 137                 ) ) then
 138                         match = false
 139                 end
 140
 141                 -- match source
 142                 if not ( match == true and (
 143                         not args.source or rule.source == self._nulladdr or
 144                         self:_parse_addr(rule.source):contains(args.source)
 145                 ) ) then
 146                         match = false
 147                 end
 148
 149                 -- match destination
 150                 if not ( match == true and (
 151                         not args.destination or rule.destination == self._nulladdr or
 152                         self:_parse_addr(rule.destination):contains(args.destination)
 153                 ) ) then
 154                         match = false
 155                 end
 156
 157                 -- match input interface
 158                 if not ( match == true and (
 159                         not args.inputif or rule.inputif == "*" or
 160                         args.inputif == rule.inputif
 161                 ) ) then
 162                         match = false
 163                 end
 164
 165                 -- match output interface
 166                 if not ( match == true and (
 167                         not args.outputif or rule.outputif == "*" or
 168                         args.outputif == rule.outputif
 169                 ) ) then
 170                         match = false
 171                 end
 172
 173                 -- match flags (the "opt" column)
 174                 if not ( match == true and (
 175                         not args.flags or rule.flags == args.flags
 176                 ) ) then
 177                         match = false
 178                 end
 179
 180                 -- match specific options
 181                 if not ( match == true and (
 182                         not args.options or
 183                         self:_match_options( rule.options, args.options )
 184                 ) ) then
 185                         match = false
 186                 end
 187
 188                 -- insert match
 189                 if match == true then
 190                         rv[#rv+1] = rule
 191                 end
 192         end
 193
 194         return rv
 195 end
 196
 197
 198 -- through external commands.
 199 function IptParser.resync( self )
 200         self._rules = { }
 201         self._chain = nil
 202         self:_parse_rules()
 203 end
 204
 205
 206 function IptParser.tables( self )
 207         return self._tables
 208 end
 209
 210
 211 function IptParser.chains( self, table )
 212         local lookup = { }
 213         local chains = { }
 214         for _, r in ipairs(self:find({table=table})) do
 215                 if not lookup[r.chain] then
 216                         lookup[r.chain]   = true
 217                         chains[#chains+1] = r.chain
 218                 end
 219         end
 220         return chains
 221 end
 222
 223
 224 --                              and "rules". The "rules" field is a table of rule tables.
 225 function IptParser.chain( self, table, chain )
 226         return self._chains[table:lower()] and self._chains[table:lower()][chain]
 227 end
 228
 229
 230 function IptParser.is_custom_target( self, target )
 231         for _, r in ipairs(self._rules) do
 232                 if r.chain == target then
 233                         return true
 234                 end
 235         end
 236         return false
 237 end
 238
 239
 240 -- [internal] Parse address according to family.
 241 function IptParser._parse_addr( self, addr )
 242         if self._family == 4 then
 243                 return luci.ip.IPv4(addr)
 244         else
 245                 return luci.ip.IPv6(addr)
 246         end
 247 end
 248
 249 -- [internal] Parse iptables output from all tables.
 250 function IptParser._parse_rules( self )
 251
 252         for i, tbl in ipairs(self._tables) do
 253
 254                 self._chains[tbl] = { }
 255
 256                 for i, rule in ipairs(luci.util.execl(self._command % tbl)) do
 257
 258                         if rule:find( "^Chain " ) == 1 then
 259
 260                                 local crefs
 261                                 local cname, cpol, cpkt, cbytes = rule:match(
 262                                         "^Chain ([^%s]*) %(policy (%w+) " ..
 263                                         "(%d+) packets, (%d+) bytes%)"
 264                                 )
 265
 266                                 if not cname then
 267                                         cname, crefs = rule:match(
 268                                                 "^Chain ([^%s]*) %((%d+) references%)"
 269                                         )
 270                                 end
 271
 272                                 self._chain = cname
 273                                 self._chains[tbl][cname] = {
 274                                         policy     = cpol,
 275                                         packets    = tonumber(cpkt or 0),
 276                                         bytes      = tonumber(cbytes or 0),
 277                                         references = tonumber(crefs or 0),
 278                                         rules      = { }
 279                                 }
 280
 281                         else
 282                                 if rule:find("%d") == 1 then
 283
 284                                         local rule_parts   = luci.util.split( rule, "%s+", nil, true )
 285                                         local rule_details = { }
 286
 287                                         -- cope with rules that have no target assigned
 288                                         if rule:match("^%d+%s+%d+%s+%d+%s%s") then
 289                                                 table.insert(rule_parts, 4, nil)
 290                                         end
 291
 292                                         -- ip6tables opt column is usually zero-width
 293                                         if self._family == 6 then
 294                                                 table.insert(rule_parts, 6, "--")
 295                                         end
 296
 297                                         rule_details["table"]       = tbl
 298                                         rule_details["chain"]       = self._chain
 299                                         rule_details["index"]       = tonumber(rule_parts[1])
 300                                         rule_details["packets"]     = tonumber(rule_parts[2])
 301                                         rule_details["bytes"]       = tonumber(rule_parts[3])
 302                                         rule_details["target"]      = rule_parts[4]
 303                                         rule_details["protocol"]    = rule_parts[5]
 304                                         rule_details["flags"]       = rule_parts[6]
 305                                         rule_details["inputif"]     = rule_parts[7]
 306                                         rule_details["outputif"]    = rule_parts[8]
 307                                         rule_details["source"]      = rule_parts[9]
 308                                         rule_details["destination"] = rule_parts[10]
 309                                         rule_details["options"]     = { }
 310
 311                                         for i = 11, #rule_parts  do
 312                                                 if #rule_parts[i] > 0 then
 313                                                         rule_details["options"][i-10] = rule_parts[i]
 314                                                 end
 315                                         end
 316
 317                                         self._rules[#self._rules+1] = rule_details
 318
 319                                         self._chains[tbl][self._chain].rules[
 320                                                 #self._chains[tbl][self._chain].rules + 1
 321                                         ] = rule_details
 322                                 end
 323                         end
 324                 end
 325         end
 326
 327         self._chain = nil
 328 end
 329
 330
 331 -- [internal] Return true if optlist1 contains all elements of optlist 2.
 332 --            Return false in all other cases.
 333 function IptParser._match_options( self, o1, o2 )
 334
 335         -- construct a hashtable of first options list to speed up lookups
 336         local oh = { }
 337         for i, opt in ipairs( o1 ) do oh[opt] = true end
 338
 339         -- iterate over second options list
 340         -- each string in o2 must be also present in o1
 341         -- if o2 contains a string which is not found in o1 then return false
 342         for i, opt in ipairs( o2 ) do
 343                 if not oh[opt] then
 344                         return false
 345                 end
 346         end
 347
 348         return true
 349 end