libs/sys/luasrc/sys/iptparser.lua

   1 --[[
   2
   3 Iptables parser and query library
   4 (c) 2008-2009 Jo-Philipp Wich <xm@leipzig.freifunk.net>
   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 --- 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 -- @param       family  Number specifying the address family. 4 for IPv4, 6 for IPv6
  32 -- @return      IptParser instance
  33 IptParser = luci.util.class()
  34
  35 function IptParser.__init__( self, family )
  36         self._family = (tonumber(family) == 6) and 6 or 4
  37         self._rules  = { }
  38         self._chains = { }
  39
  40         if self._family == 4 then
  41                 self._nulladdr = "0.0.0.0/0"
  42                 self._tables   = { "filter", "nat", "mangle", "raw" }
  43                 self._command  = "iptables -t %s --line-numbers -nxvL"
  44         else
  45                 self._nulladdr = "::/0"
  46                 self._tables   = { "filter", "mangle", "raw" }
  47                 self._command  = "ip6tables -t %s --line-numbers -nxvL"
  48         end
  49
  50         self:_parse_rules()
  51 end
  52
  53 --- Find all firewall rules that match the given criteria. Expects a table with
  54 -- search criteria as only argument. If args is nil or an empty table then all
  55 -- rules will be returned.
  56 --
  57 -- The following keys in the args table are recognized:
  58 -- <ul>
  59 --  <li> table           - Match rules that are located within the given table
  60 --  <li> chain           - Match rules that are located within the given chain
  61 --  <li> target          - Match rules with the given target
  62 --  <li> protocol        - Match rules that match the given protocol, rules with
  63 --                                              protocol "all" are always matched
  64 --  <li> source          - Match rules with the given source, rules with source
  65 --                                              "0.0.0.0/0" (::/0) are always matched
  66 --  <li> destination - Match rules with the given destination, rules with
  67 --                                              destination "0.0.0.0/0" (::/0) are always matched
  68 --  <li> inputif         - Match rules with the given input interface, rules
  69 --                                              with input      interface "*" (=all) are always matched
  70 --  <li> outputif        - Match rules with the given output interface, rules
  71 --                                              with output     interface "*" (=all) are always matched
  72 --  <li> flags           - Match rules that match the given flags, current
  73 --                                              supported values are "-f" (--fragment)
  74 --                                              and "!f" (! --fragment)
  75 --  <li> options         - Match rules containing all given options
  76 -- </ul>
  77 -- The return value is a list of tables representing the matched rules.
  78 -- Each rule table contains the following fields:
  79 -- <ul>
  80 --  <li> index           - The index number of the rule
  81 --  <li> table           - The table where the rule is located, can be one
  82 --                                              of "filter", "nat" or "mangle"
  83 --  <li> chain           - The chain where the rule is located, e.g. "INPUT"
  84 --                                              or "postrouting_wan"
  85 --  <li> target          - The rule target, e.g. "REJECT" or "DROP"
  86 --  <li> protocol               The matching protocols, e.g. "all" or "tcp"
  87 --  <li> flags           - Special rule options ("--", "-f" or "!f")
  88 --  <li> inputif         - Input interface of the rule, e.g. "eth0.0"
  89 --                                              or "*" for all interfaces
  90 --  <li> outputif        - Output interface of the rule,e.g. "eth0.0"
  91 --                                              or "*" for all interfaces
  92 --  <li> source          - The source ip range, e.g. "0.0.0.0/0" (::/0)
  93 --  <li> destination - The destination ip range, e.g. "0.0.0.0/0" (::/0)
  94 --  <li> options         - A list of specific options of the rule,
  95 --                                              e.g. { "reject-with", "tcp-reset" }
  96 --  <li> packets         - The number of packets matched by the rule
  97 --  <li> bytes           - The number of total bytes matched by the rule
  98 -- </ul>
  99 -- Example:
 100 -- <pre>
 101 -- ip = luci.sys.iptparser.IptParser()
 102 -- result = ip.find( {
 103 --      target="REJECT",
 104 --      protocol="tcp",
 105 --      options={ "reject-with", "tcp-reset" }
 106 -- } )
 107 -- </pre>
 108 -- This will match all rules with target "-j REJECT",
 109 -- protocol "-p tcp" (or "-p all")
 110 -- and the option "--reject-with tcp-reset".
 111 -- @params args         Table containing the search arguments (optional)
 112 -- @return                      Table of matching rule tables
 113 function IptParser.find( self, args )
 114
 115         local args = args or { }
 116         local rv   = { }
 117
 118         args.source      = args.source      and self:_parse_addr(args.source)
 119         args.destination = args.destination and self:_parse_addr(args.destination)
 120
 121         for i, rule in ipairs(self._rules) do
 122                 local match = true
 123
 124                 -- match table
 125                 if not ( not args.table or args.table:lower() == rule.table ) then
 126                         match = false
 127                 end
 128
 129                 -- match chain
 130                 if not ( match == true and (
 131                         not args.chain or args.chain == rule.chain
 132                 ) ) then
 133                         match = false
 134                 end
 135
 136                 -- match target
 137                 if not ( match == true and (
 138                         not args.target or args.target == rule.target
 139                 ) ) then
 140                         match = false
 141                 end
 142
 143                 -- match protocol
 144                 if not ( match == true and (
 145                         not args.protocol or rule.protocol == "all" or
 146                         args.protocol:lower() == rule.protocol
 147                 ) ) then
 148                         match = false
 149                 end
 150
 151                 -- match source
 152                 if not ( match == true and (
 153                         not args.source or rule.source == self._nulladdr or
 154                         self:_parse_addr(rule.source):contains(args.source)
 155                 ) ) then
 156                         match = false
 157                 end
 158
 159                 -- match destination
 160                 if not ( match == true and (
 161                         not args.destination or rule.destination == self._nulladdr or
 162                         self:_parse_addr(rule.destination):contains(args.destination)
 163                 ) ) then
 164                         match = false
 165                 end
 166
 167                 -- match input interface
 168                 if not ( match == true and (
 169                         not args.inputif or rule.inputif == "*" or
 170                         args.inputif == rule.inputif
 171                 ) ) then
 172                         match = false
 173                 end
 174
 175                 -- match output interface
 176                 if not ( match == true and (
 177                         not args.outputif or rule.outputif == "*" or
 178                         args.outputif == rule.outputif
 179                 ) ) then
 180                         match = false
 181                 end
 182
 183                 -- match flags (the "opt" column)
 184                 if not ( match == true and (
 185                         not args.flags or rule.flags == args.flags
 186                 ) ) then
 187                         match = false
 188                 end
 189
 190                 -- match specific options
 191                 if not ( match == true and (
 192                         not args.options or
 193                         self:_match_options( rule.options, args.options )
 194                 ) ) then
 195                         match = false
 196                 end
 197
 198                 -- insert match
 199                 if match == true then
 200                         rv[#rv+1] = rule
 201                 end
 202         end
 203
 204         return rv
 205 end
 206
 207
 208 --- Rebuild the internal lookup table, for example when rules have changed
 209 -- through external commands.
 210 -- @return      nothing
 211 function IptParser.resync( self )
 212         self._rules = { }
 213         self._chain = nil
 214         self:_parse_rules()
 215 end
 216
 217
 218 --- Find the names of all chains within the given table name.
 219 -- @param table String containing the table name
 220 -- @return              Table of chain names in the order they occur.
 221 function IptParser.chains( self, table )
 222         local lookup = { }
 223         local chains = { }
 224         for _, r in ipairs(self:find({table=table})) do
 225                 if not lookup[r.chain] then
 226                         lookup[r.chain]   = true
 227                         chains[#chains+1] = r.chain
 228                 end
 229         end
 230         return chains
 231 end
 232
 233
 234 --- Return the given firewall chain within the given table name.
 235 -- @param table String containing the table name
 236 -- @param chain String containing the chain name
 237 -- @return              Table containing the fields "policy", "packets", "bytes"
 238 --                              and "rules". The "rules" field is a table of rule tables.
 239 function IptParser.chain( self, table, chain )
 240         return self._chains[table:lower()] and self._chains[table:lower()][chain]
 241 end
 242
 243
 244 --- Test whether the given target points to a custom chain.
 245 -- @param target        String containing the target action
 246 -- @return                      Boolean indicating whether target is a custom chain.
 247 function IptParser.is_custom_target( self, target )
 248         for _, r in ipairs(self._rules) do
 249                 if r.chain == target then
 250                         return true
 251                 end
 252         end
 253         return false
 254 end
 255
 256
 257 -- [internal] Parse address according to family.
 258 function IptParser._parse_addr( self, addr )
 259         if self._family == 4 then
 260                 return luci.ip.IPv4(addr)
 261         else
 262                 return luci.ip.IPv6(addr)
 263         end
 264 end
 265
 266 -- [internal] Parse iptables output from all tables.
 267 function IptParser._parse_rules( self )
 268
 269         for i, tbl in ipairs(self._tables) do
 270
 271                 self._chains[tbl] = { }
 272
 273                 for i, rule in ipairs(luci.util.execl(self._command % tbl)) do
 274
 275                         if rule:find( "^Chain " ) == 1 then
 276
 277                                 local crefs
 278                                 local cname, cpol, cpkt, cbytes = rule:match(
 279                                         "^Chain ([^%s]*) %(policy (%w+) " ..
 280                                         "(%d+) packets, (%d+) bytes%)"
 281                                 )
 282
 283                                 if not cname then
 284                                         cname, crefs = rule:match(
 285                                                 "^Chain ([^%s]*) %((%d+) references%)"
 286                                         )
 287                                 end
 288
 289                                 self._chain = cname
 290                                 self._chains[tbl][cname] = {
 291                                         policy     = cpol,
 292                                         packets    = tonumber(cpkt or 0),
 293                                         bytes      = tonumber(cbytes or 0),
 294                                         references = tonumber(crefs or 0),
 295                                         rules      = { }
 296                                 }
 297
 298                         else
 299                                 if rule:find("%d") == 1 then
 300
 301                                         local rule_parts   = luci.util.split( rule, "%s+", nil, true )
 302                                         local rule_details = { }
 303
 304                                         -- cope with rules that have no target assigned
 305                                         if rule:match("^%d+%s+%d+%s+%d+%s%s") then
 306                                                 table.insert(rule_parts, 4, nil)
 307                                         end
 308
 309                                         rule_details["table"]       = tbl
 310                                         rule_details["chain"]       = self._chain
 311                                         rule_details["index"]       = tonumber(rule_parts[1])
 312                                         rule_details["packets"]     = tonumber(rule_parts[2])
 313                                         rule_details["bytes"]       = tonumber(rule_parts[3])
 314                                         rule_details["target"]      = rule_parts[4]
 315                                         rule_details["protocol"]    = rule_parts[5]
 316                                         rule_details["flags"]       = rule_parts[6]
 317                                         rule_details["inputif"]     = rule_parts[7]
 318                                         rule_details["outputif"]    = rule_parts[8]
 319                                         rule_details["source"]      = rule_parts[9]
 320                                         rule_details["destination"] = rule_parts[10]
 321                                         rule_details["options"]     = { }
 322
 323                                         for i = 11, #rule_parts - 1 do
 324                                                 rule_details["options"][i-10] = rule_parts[i]
 325                                         end
 326
 327                                         self._rules[#self._rules+1] = rule_details
 328
 329                                         self._chains[tbl][self._chain].rules[
 330                                                 #self._chains[tbl][self._chain].rules + 1
 331                                         ] = rule_details
 332                                 end
 333                         end
 334                 end
 335         end
 336
 337         self._chain = nil
 338 end
 339
 340
 341 -- [internal] Return true if optlist1 contains all elements of optlist 2.
 342 --            Return false in all other cases.
 343 function IptParser._match_options( self, o1, o2 )
 344
 345         -- construct a hashtable of first options list to speed up lookups
 346         local oh = { }
 347         for i, opt in ipairs( o1 ) do oh[opt] = true end
 348
 349         -- iterate over second options list
 350         -- each string in o2 must be also present in o1
 351         -- if o2 contains a string which is not found in o1 then return false
 352         for i, opt in ipairs( o2 ) do
 353                 if not oh[opt] then
 354                         return false
 355                 end
 356         end
 357
 358         return true
 359 end