--- /dev/null
+--[[
+
+Iptables parser and query library
+(c) 2008-2009 Jo-Philipp Wich <xm@leipzig.freifunk.net>
+(c) 2008-2009 Steven Barth <steven@midlink.org>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+$Id$
+
+]]--
+
+local luci = {}
+luci.util = require "luci.util"
+luci.sys = require "luci.sys"
+luci.ip = require "luci.ip"
+
+local tonumber, ipairs, table = tonumber, ipairs, table
+
+--- LuCI iptables parser and query library
+-- @cstyle instance
+module("luci.sys.iptparser")
+
+--- Create a new iptables parser object.
+-- @class function
+-- @name IptParser
+-- @param family Number specifying the address family. 4 for IPv4, 6 for IPv6
+-- @return IptParser instance
+IptParser = luci.util.class()
+
+function IptParser.__init__( self, family )
+ self._family = (tonumber(family) == 6) and 6 or 4
+ self._rules = { }
+ self._chains = { }
+
+ if self._family == 4 then
+ self._nulladdr = "0.0.0.0/0"
+ self._tables = { "filter", "nat", "mangle", "raw" }
+ self._command = "iptables -t %s --line-numbers -nxvL"
+ else
+ self._nulladdr = "::/0"
+ self._tables = { "filter", "mangle", "raw" }
+ self._command = "ip6tables -t %s --line-numbers -nxvL"
+ end
+
+ self:_parse_rules()
+end
+
+--- Find all firewall rules that match the given criteria. Expects a table with
+-- search criteria as only argument. If args is nil or an empty table then all
+-- rules will be returned.
+--
+-- The following keys in the args table are recognized:
+-- <ul>
+-- <li> table - Match rules that are located within the given table
+-- <li> chain - Match rules that are located within the given chain
+-- <li> target - Match rules with the given target
+-- <li> protocol - Match rules that match the given protocol, rules with
+-- protocol "all" are always matched
+-- <li> source - Match rules with the given source, rules with source
+-- "0.0.0.0/0" (::/0) are always matched
+-- <li> destination - Match rules with the given destination, rules with
+-- destination "0.0.0.0/0" (::/0) are always matched
+-- <li> inputif - Match rules with the given input interface, rules
+-- with input interface "*" (=all) are always matched
+-- <li> outputif - Match rules with the given output interface, rules
+-- with output interface "*" (=all) are always matched
+-- <li> flags - Match rules that match the given flags, current
+-- supported values are "-f" (--fragment)
+-- and "!f" (! --fragment)
+-- <li> options - Match rules containing all given options
+-- </ul>
+-- The return value is a list of tables representing the matched rules.
+-- Each rule table contains the following fields:
+-- <ul>
+-- <li> index - The index number of the rule
+-- <li> table - The table where the rule is located, can be one
+-- of "filter", "nat" or "mangle"
+-- <li> chain - The chain where the rule is located, e.g. "INPUT"
+-- or "postrouting_wan"
+-- <li> target - The rule target, e.g. "REJECT" or "DROP"
+-- <li> protocol The matching protocols, e.g. "all" or "tcp"
+-- <li> flags - Special rule options ("--", "-f" or "!f")
+-- <li> inputif - Input interface of the rule, e.g. "eth0.0"
+-- or "*" for all interfaces
+-- <li> outputif - Output interface of the rule,e.g. "eth0.0"
+-- or "*" for all interfaces
+-- <li> source - The source ip range, e.g. "0.0.0.0/0" (::/0)
+-- <li> destination - The destination ip range, e.g. "0.0.0.0/0" (::/0)
+-- <li> options - A list of specific options of the rule,
+-- e.g. { "reject-with", "tcp-reset" }
+-- <li> packets - The number of packets matched by the rule
+-- <li> bytes - The number of total bytes matched by the rule
+-- </ul>
+-- Example:
+-- <pre>
+-- ip = luci.sys.iptparser.IptParser()
+-- result = ip.find( {
+-- target="REJECT",
+-- protocol="tcp",
+-- options={ "reject-with", "tcp-reset" }
+-- } )
+-- </pre>
+-- This will match all rules with target "-j REJECT",
+-- protocol "-p tcp" (or "-p all")
+-- and the option "--reject-with tcp-reset".
+-- @params args Table containing the search arguments (optional)
+-- @return Table of matching rule tables
+function IptParser.find( self, args )
+
+ local args = args or { }
+ local rv = { }
+
+ args.source = args.source and self:_parse_addr(args.source)
+ args.destination = args.destination and self:_parse_addr(args.destination)
+
+ for i, rule in ipairs(self._rules) do
+ local match = true
+
+ -- match table
+ if not ( not args.table or args.table:lower() == rule.table ) then
+ match = false
+ end
+
+ -- match chain
+ if not ( match == true and (
+ not args.chain or args.chain == rule.chain
+ ) ) then
+ match = false
+ end
+
+ -- match target
+ if not ( match == true and (
+ not args.target or args.target == rule.target
+ ) ) then
+ match = false
+ end
+
+ -- match protocol
+ if not ( match == true and (
+ not args.protocol or rule.protocol == "all" or
+ args.protocol:lower() == rule.protocol
+ ) ) then
+ match = false
+ end
+
+ -- match source
+ if not ( match == true and (
+ not args.source or rule.source == self._nulladdr or
+ self:_parse_addr(rule.source):contains(args.source)
+ ) ) then
+ match = false
+ end
+
+ -- match destination
+ if not ( match == true and (
+ not args.destination or rule.destination == self._nulladdr or
+ self:_parse_addr(rule.destination):contains(args.destination)
+ ) ) then
+ match = false
+ end
+
+ -- match input interface
+ if not ( match == true and (
+ not args.inputif or rule.inputif == "*" or
+ args.inputif == rule.inputif
+ ) ) then
+ match = false
+ end
+
+ -- match output interface
+ if not ( match == true and (
+ not args.outputif or rule.outputif == "*" or
+ args.outputif == rule.outputif
+ ) ) then
+ match = false
+ end
+
+ -- match flags (the "opt" column)
+ if not ( match == true and (
+ not args.flags or rule.flags == args.flags
+ ) ) then
+ match = false
+ end
+
+ -- match specific options
+ if not ( match == true and (
+ not args.options or
+ self:_match_options( rule.options, args.options )
+ ) ) then
+ match = false
+ end
+
+ -- insert match
+ if match == true then
+ rv[#rv+1] = rule
+ end
+ end
+
+ return rv
+end
+
+
+--- Rebuild the internal lookup table, for example when rules have changed
+-- through external commands.
+-- @return nothing
+function IptParser.resync( self )
+ self._rules = { }
+ self._chain = nil
+ self:_parse_rules()
+end
+
+
+--- Find the names of all tables.
+-- @return Table of table names.
+function IptParser.tables( self )
+ return self._tables
+end
+
+
+--- Find the names of all chains within the given table name.
+-- @param table String containing the table name
+-- @return Table of chain names in the order they occur.
+function IptParser.chains( self, table )
+ local lookup = { }
+ local chains = { }
+ for _, r in ipairs(self:find({table=table})) do
+ if not lookup[r.chain] then
+ lookup[r.chain] = true
+ chains[#chains+1] = r.chain
+ end
+ end
+ return chains
+end
+
+
+--- Return the given firewall chain within the given table name.
+-- @param table String containing the table name
+-- @param chain String containing the chain name
+-- @return Table containing the fields "policy", "packets", "bytes"
+-- and "rules". The "rules" field is a table of rule tables.
+function IptParser.chain( self, table, chain )
+ return self._chains[table:lower()] and self._chains[table:lower()][chain]
+end
+
+
+--- Test whether the given target points to a custom chain.
+-- @param target String containing the target action
+-- @return Boolean indicating whether target is a custom chain.
+function IptParser.is_custom_target( self, target )
+ for _, r in ipairs(self._rules) do
+ if r.chain == target then
+ return true
+ end
+ end
+ return false
+end
+
+
+-- [internal] Parse address according to family.
+function IptParser._parse_addr( self, addr )
+ if self._family == 4 then
+ return luci.ip.IPv4(addr)
+ else
+ return luci.ip.IPv6(addr)
+ end
+end
+
+-- [internal] Parse iptables output from all tables.
+function IptParser._parse_rules( self )
+
+ for i, tbl in ipairs(self._tables) do
+
+ self._chains[tbl] = { }
+
+ for i, rule in ipairs(luci.util.execl(self._command % tbl)) do
+
+ if rule:find( "^Chain " ) == 1 then
+
+ local crefs
+ local cname, cpol, cpkt, cbytes = rule:match(
+ "^Chain ([^%s]*) %(policy (%w+) " ..
+ "(%d+) packets, (%d+) bytes%)"
+ )
+
+ if not cname then
+ cname, crefs = rule:match(
+ "^Chain ([^%s]*) %((%d+) references%)"
+ )
+ end
+
+ self._chain = cname
+ self._chains[tbl][cname] = {
+ policy = cpol,
+ packets = tonumber(cpkt or 0),
+ bytes = tonumber(cbytes or 0),
+ references = tonumber(crefs or 0),
+ rules = { }
+ }
+
+ else
+ if rule:find("%d") == 1 then
+
+ local rule_parts = luci.util.split( rule, "%s+", nil, true )
+ local rule_details = { }
+
+ -- cope with rules that have no target assigned
+ if rule:match("^%d+%s+%d+%s+%d+%s%s") then
+ table.insert(rule_parts, 4, nil)
+ end
+
+ -- ip6tables opt column is usually zero-width
+ if self._family == 6 then
+ table.insert(rule_parts, 6, "--")
+ end
+
+ rule_details["table"] = tbl
+ rule_details["chain"] = self._chain
+ rule_details["index"] = tonumber(rule_parts[1])
+ rule_details["packets"] = tonumber(rule_parts[2])
+ rule_details["bytes"] = tonumber(rule_parts[3])
+ rule_details["target"] = rule_parts[4]
+ rule_details["protocol"] = rule_parts[5]
+ rule_details["flags"] = rule_parts[6]
+ rule_details["inputif"] = rule_parts[7]
+ rule_details["outputif"] = rule_parts[8]
+ rule_details["source"] = rule_parts[9]
+ rule_details["destination"] = rule_parts[10]
+ rule_details["options"] = { }
+
+ for i = 11, #rule_parts do
+ if #rule_parts[i] > 0 then
+ rule_details["options"][i-10] = rule_parts[i]
+ end
+ end
+
+ self._rules[#self._rules+1] = rule_details
+
+ self._chains[tbl][self._chain].rules[
+ #self._chains[tbl][self._chain].rules + 1
+ ] = rule_details
+ end
+ end
+ end
+ end
+
+ self._chain = nil
+end
+
+
+-- [internal] Return true if optlist1 contains all elements of optlist 2.
+-- Return false in all other cases.
+function IptParser._match_options( self, o1, o2 )
+
+ -- construct a hashtable of first options list to speed up lookups
+ local oh = { }
+ for i, opt in ipairs( o1 ) do oh[opt] = true end
+
+ -- iterate over second options list
+ -- each string in o2 must be also present in o1
+ -- if o2 contains a string which is not found in o1 then return false
+ for i, opt in ipairs( o2 ) do
+ if not oh[opt] then
+ return false
+ end
+ end
+
+ return true
+end
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