libs/luci-lib-iptparser/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 pcall = pcall
  23 local io = require "io"
  24 local tonumber, ipairs, table = tonumber, ipairs, table
  25
  26 module("luci.sys.iptparser")
  27
  28 IptParser = luci.util.class()
  29
  30 function IptParser.__init__( self, family )
  31         self._family = (tonumber(family) == 6) and 6 or 4
  32         self._rules  = { }
  33         self._chains = { }
  34         self._tables = { }
  35
  36         local t = self._tables
  37         local s = self:_supported_tables(self._family)
  38
  39         if s.filter then t[#t+1] = "filter" end
  40         if s.nat    then t[#t+1] = "nat"    end
  41         if s.mangle then t[#t+1] = "mangle" end
  42         if s.raw    then t[#t+1] = "raw"    end
  43
  44         if self._family == 4 then
  45                 self._nulladdr = "0.0.0.0/0"
  46                 self._command  = "iptables -t %s --line-numbers -nxvL"
  47         else
  48                 self._nulladdr = "::/0"
  49                 self._command  = "ip6tables -t %s --line-numbers -nxvL"
  50         end
  51
  52         self:_parse_rules()
  53 end
  54
  55 function IptParser._supported_tables( self, family )
  56         local tables = { }
  57         local ok, lines = pcall(io.lines,
  58                 (family == 6) and "/proc/net/ip6_tables_names"
  59                                or "/proc/net/ip_tables_names")
  60
  61         if ok and lines then
  62                 local line
  63                 for line in lines do
  64                         tables[line] = true
  65                 end
  66         end
  67
  68         return tables
  69 end
  70
  71 -- search criteria as only argument. If args is nil or an empty table then all
  72 -- rules will be returned.
  73 --
  74 -- The following keys in the args table are recognized:
  75 -- <ul>
  76 --  <li> table           - Match rules that are located within the given table
  77 --  <li> chain           - Match rules that are located within the given chain
  78 --  <li> target          - Match rules with the given target
  79 --  <li> protocol        - Match rules that match the given protocol, rules with
  80 --                                              protocol "all" are always matched
  81 --  <li> source          - Match rules with the given source, rules with source
  82 --                                              "0.0.0.0/0" (::/0) are always matched
  83 --  <li> destination - Match rules with the given destination, rules with
  84 --                                              destination "0.0.0.0/0" (::/0) are always matched
  85 --  <li> inputif         - Match rules with the given input interface, rules
  86 --                                              with input      interface "*" (=all) are always matched
  87 --  <li> outputif        - Match rules with the given output interface, rules
  88 --                                              with output     interface "*" (=all) are always matched
  89 --  <li> flags           - Match rules that match the given flags, current
  90 --                                              supported values are "-f" (--fragment)
  91 --                                              and "!f" (! --fragment)
  92 --  <li> options         - Match rules containing all given options
  93 -- </ul>
  94 -- The return value is a list of tables representing the matched rules.
  95 -- Each rule table contains the following fields:
  96 -- <ul>
  97 --  <li> index           - The index number of the rule
  98 --  <li> table           - The table where the rule is located, can be one
  99 --                                              of "filter", "nat" or "mangle"
 100 --  <li> chain           - The chain where the rule is located, e.g. "INPUT"
 101 --                                              or "postrouting_wan"
 102 --  <li> target          - The rule target, e.g. "REJECT" or "DROP"
 103 --  <li> protocol               The matching protocols, e.g. "all" or "tcp"
 104 --  <li> flags           - Special rule options ("--", "-f" or "!f")
 105 --  <li> inputif         - Input interface of the rule, e.g. "eth0.0"
 106 --                                              or "*" for all interfaces
 107 --  <li> outputif        - Output interface of the rule,e.g. "eth0.0"
 108 --                                              or "*" for all interfaces
 109 --  <li> source          - The source ip range, e.g. "0.0.0.0/0" (::/0)
 110 --  <li> destination - The destination ip range, e.g. "0.0.0.0/0" (::/0)
 111 --  <li> options         - A list of specific options of the rule,
 112 --                                              e.g. { "reject-with", "tcp-reset" }
 113 --  <li> packets         - The number of packets matched by the rule
 114 --  <li> bytes           - The number of total bytes matched by the rule
 115 -- </ul>
 116 -- Example:
 117 -- <pre>
 118 -- ip = luci.sys.iptparser.IptParser()
 119 -- result = ip.find( {
 120 --      target="REJECT",
 121 --      protocol="tcp",
 122 --      options={ "reject-with", "tcp-reset" }
 123 -- } )
 124 -- </pre>
 125 -- This will match all rules with target "-j REJECT",
 126 -- protocol "-p tcp" (or "-p all")
 127 -- and the option "--reject-with tcp-reset".
 128 function IptParser.find( self, args )
 129
 130         local args = args or { }
 131         local rv   = { }
 132
 133         args.source      = args.source      and self:_parse_addr(args.source)
 134         args.destination = args.destination and self:_parse_addr(args.destination)
 135
 136         for i, rule in ipairs(self._rules) do
 137                 local match = true
 138
 139                 -- match table
 140                 if not ( not args.table or args.table:lower() == rule.table ) then
 141                         match = false
 142                 end
 143
 144                 -- match chain
 145                 if not ( match == true and (
 146                         not args.chain or args.chain == rule.chain
 147                 ) ) then
 148                         match = false
 149                 end
 150
 151                 -- match target
 152                 if not ( match == true and (
 153                         not args.target or args.target == rule.target
 154                 ) ) then
 155                         match = false
 156                 end
 157
 158                 -- match protocol
 159                 if not ( match == true and (
 160                         not args.protocol or rule.protocol == "all" or
 161                         args.protocol:lower() == rule.protocol
 162                 ) ) then
 163                         match = false
 164                 end
 165
 166                 -- match source
 167                 if not ( match == true and (
 168                         not args.source or rule.source == self._nulladdr or
 169                         self:_parse_addr(rule.source):contains(args.source)
 170                 ) ) then
 171                         match = false
 172                 end
 173
 174                 -- match destination
 175                 if not ( match == true and (
 176                         not args.destination or rule.destination == self._nulladdr or
 177                         self:_parse_addr(rule.destination):contains(args.destination)
 178                 ) ) then
 179                         match = false
 180                 end
 181
 182                 -- match input interface
 183                 if not ( match == true and (
 184                         not args.inputif or rule.inputif == "*" or
 185                         args.inputif == rule.inputif
 186                 ) ) then
 187                         match = false
 188                 end
 189
 190                 -- match output interface
 191                 if not ( match == true and (
 192                         not args.outputif or rule.outputif == "*" or
 193                         args.outputif == rule.outputif
 194                 ) ) then
 195                         match = false
 196                 end
 197
 198                 -- match flags (the "opt" column)
 199                 if not ( match == true and (
 200                         not args.flags or rule.flags == args.flags
 201                 ) ) then
 202                         match = false
 203                 end
 204
 205                 -- match specific options
 206                 if not ( match == true and (
 207                         not args.options or
 208                         self:_match_options( rule.options, args.options )
 209                 ) ) then
 210                         match = false
 211                 end
 212
 213                 -- insert match
 214                 if match == true then
 215                         rv[#rv+1] = rule
 216                 end
 217         end
 218
 219         return rv
 220 end
 221
 222
 223 -- through external commands.
 224 function IptParser.resync( self )
 225         self._rules = { }
 226         self._chain = nil
 227         self:_parse_rules()
 228 end
 229
 230
 231 function IptParser.tables( self )
 232         return self._tables
 233 end
 234
 235
 236 function IptParser.chains( self, table )
 237         local lookup = { }
 238         local chains = { }
 239         for _, r in ipairs(self:find({table=table})) do
 240                 if not lookup[r.chain] then
 241                         lookup[r.chain]   = true
 242                         chains[#chains+1] = r.chain
 243                 end
 244         end
 245         return chains
 246 end
 247
 248
 249 --                              and "rules". The "rules" field is a table of rule tables.
 250 function IptParser.chain( self, table, chain )
 251         return self._chains[table:lower()] and self._chains[table:lower()][chain]
 252 end
 253
 254
 255 function IptParser.is_custom_target( self, target )
 256         for _, r in ipairs(self._rules) do
 257                 if r.chain == target then
 258                         return true
 259                 end
 260         end
 261         return false
 262 end
 263
 264
 265 -- [internal] Parse address according to family.
 266 function IptParser._parse_addr( self, addr )
 267         if self._family == 4 then
 268                 return luci.ip.IPv4(addr)
 269         else
 270                 return luci.ip.IPv6(addr)
 271         end
 272 end
 273
 274 -- [internal] Parse iptables output from all tables.
 275 function IptParser._parse_rules( self )
 276
 277         for i, tbl in ipairs(self._tables) do
 278
 279                 self._chains[tbl] = { }
 280
 281                 for i, rule in ipairs(luci.util.execl(self._command % tbl)) do
 282
 283                         if rule:find( "^Chain " ) == 1 then
 284
 285                                 local crefs
 286                                 local cname, cpol, cpkt, cbytes = rule:match(
 287                                         "^Chain ([^%s]*) %(policy (%w+) " ..
 288                                         "(%d+) packets, (%d+) bytes%)"
 289                                 )
 290
 291                                 if not cname then
 292                                         cname, crefs = rule:match(
 293                                                 "^Chain ([^%s]*) %((%d+) references%)"
 294                                         )
 295                                 end
 296
 297                                 self._chain = cname
 298                                 self._chains[tbl][cname] = {
 299                                         policy     = cpol,
 300                                         packets    = tonumber(cpkt or 0),
 301                                         bytes      = tonumber(cbytes or 0),
 302                                         references = tonumber(crefs or 0),
 303                                         rules      = { }
 304                                 }
 305
 306                         else
 307                                 if rule:find("%d") == 1 then
 308
 309                                         local rule_parts   = luci.util.split( rule, "%s+", nil, true )
 310                                         local rule_details = { }
 311
 312                                         -- cope with rules that have no target assigned
 313                                         if rule:match("^%d+%s+%d+%s+%d+%s%s") then
 314                                                 table.insert(rule_parts, 4, nil)
 315                                         end
 316
 317                                         -- ip6tables opt column is usually zero-width
 318                                         if self._family == 6 then
 319                                                 table.insert(rule_parts, 6, "--")
 320                                         end
 321
 322                                         rule_details["table"]       = tbl
 323                                         rule_details["chain"]       = self._chain
 324                                         rule_details["index"]       = tonumber(rule_parts[1])
 325                                         rule_details["packets"]     = tonumber(rule_parts[2])
 326                                         rule_details["bytes"]       = tonumber(rule_parts[3])
 327                                         rule_details["target"]      = rule_parts[4]
 328                                         rule_details["protocol"]    = rule_parts[5]
 329                                         rule_details["flags"]       = rule_parts[6]
 330                                         rule_details["inputif"]     = rule_parts[7]
 331                                         rule_details["outputif"]    = rule_parts[8]
 332                                         rule_details["source"]      = rule_parts[9]
 333                                         rule_details["destination"] = rule_parts[10]
 334                                         rule_details["options"]     = { }
 335
 336                                         for i = 11, #rule_parts  do
 337                                                 if #rule_parts[i] > 0 then
 338                                                         rule_details["options"][i-10] = rule_parts[i]
 339                                                 end
 340                                         end
 341
 342                                         self._rules[#self._rules+1] = rule_details
 343
 344                                         self._chains[tbl][self._chain].rules[
 345                                                 #self._chains[tbl][self._chain].rules + 1
 346                                         ] = rule_details
 347                                 end
 348                         end
 349                 end
 350         end
 351
 352         self._chain = nil
 353 end
 354
 355
 356 -- [internal] Return true if optlist1 contains all elements of optlist 2.
 357 --            Return false in all other cases.
 358 function IptParser._match_options( self, o1, o2 )
 359
 360         -- construct a hashtable of first options list to speed up lookups
 361         local oh = { }
 362         for i, opt in ipairs( o1 ) do oh[opt] = true end
 363
 364         -- iterate over second options list
 365         -- each string in o2 must be also present in o1
 366         -- if o2 contains a string which is not found in o1 then return false
 367         for i, opt in ipairs( o2 ) do
 368                 if not oh[opt] then
 369                         return false
 370                 end
 371         end
 372
 373         return true
 374 end