# -*- coding: utf-8 -*-
#
# Copyright (C) 2010-2016 Red Hat, Inc.
#
# Authors:
# Thomas Woerner <twoerner@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import os.path
import copy

from firewall.core.prog import runProg
from firewall.core.logger import log
from firewall.functions import tempFile, readfile, splitArgs, check_mac, portStr, \
                               check_single_address, check_address, normalizeIP6
from firewall import config
from firewall.errors import FirewallError, INVALID_PASSTHROUGH, INVALID_RULE, UNKNOWN_ERROR, INVALID_ADDR
from firewall.core.rich import Rich_Accept, Rich_Reject, Rich_Drop, Rich_Mark, \
                               Rich_Masquerade, Rich_ForwardPort, Rich_IcmpBlock
import string

POLICY_CHAIN_PREFIX = ""

BUILT_IN_CHAINS = {
    "security": [ "INPUT", "OUTPUT", "FORWARD" ],
    "raw": [ "PREROUTING", "OUTPUT" ],
    "mangle": [ "PREROUTING", "POSTROUTING", "INPUT", "OUTPUT", "FORWARD" ],
    "nat": [ "PREROUTING", "POSTROUTING", "OUTPUT" ],
    "filter": [ "INPUT", "OUTPUT", "FORWARD" ],
}

DEFAULT_REJECT_TYPE = {
    "ipv4": "icmp-host-prohibited",
    "ipv6": "icmp6-adm-prohibited",
}

ICMP = {
    "ipv4": "icmp",
    "ipv6": "ipv6-icmp",
}

# ipv ebtables also uses this
#
def common_reverse_rule(args):
    """ Inverse valid rule """

    replace_args = {
        # Append
        "-A": "-D",
        "--append": "--delete",
        # Insert
        "-I": "-D",
        "--insert": "--delete",
        # New chain
        "-N": "-X",
        "--new-chain": "--delete-chain",
    }

    ret_args = args[:]

    for arg in replace_args:
        try:
            idx = ret_args.index(arg)
        except Exception:
            continue

        if arg in [ "-I", "--insert" ]:
            # With insert rulenum, then remove it if it is a number
            # Opt at position idx, chain at position idx+1, [rulenum] at
            # position idx+2
            try:
                int(ret_args[idx+2])
            except Exception:
                pass
            else:
                ret_args.pop(idx+2)

        ret_args[idx] = replace_args[arg]
    return ret_args

def common_reverse_passthrough(args):
    """ Reverse valid passthough rule """

    replace_args = {
        # Append
        "-A": "-D",
        "--append": "--delete",
        # Insert
        "-I": "-D",
        "--insert": "--delete",
        # New chain
        "-N": "-X",
        "--new-chain": "--delete-chain",
    }

    ret_args = args[:]

    for x in replace_args:
        try:
            idx = ret_args.index(x)
        except ValueError:
            continue

        if x in [ "-I", "--insert" ]:
            # With insert rulenum, then remove it if it is a number
            # Opt at position idx, chain at position idx+1, [rulenum] at
            # position idx+2
            try:
                int(ret_args[idx+2])
            except ValueError:
                pass
            else:
                ret_args.pop(idx+2)

        ret_args[idx] = replace_args[x]
        return ret_args

    raise FirewallError(INVALID_PASSTHROUGH,
                        "no '-A', '-I' or '-N' arg")

# ipv ebtables also uses this
#
def common_check_passthrough(args):
    """ Check if passthough rule is valid (only add, insert and new chain
    rules are allowed) """

    args = set(args)
    not_allowed = set(["-C", "--check",           # check rule
                       "-D", "--delete",          # delete rule
                       "-R", "--replace",         # replace rule
                       "-L", "--list",            # list rule
                       "-S", "--list-rules",      # print rules
                       "-F", "--flush",           # flush rules
                       "-Z", "--zero",            # zero rules
                       "-X", "--delete-chain",    # delete chain
                       "-P", "--policy",          # policy
                       "-E", "--rename-chain"])   # rename chain)
    # intersection of args and not_allowed is not empty, i.e.
    # something from args is not allowed
    if len(args & not_allowed) > 0:
        raise FirewallError(INVALID_PASSTHROUGH,
                            "arg '%s' is not allowed" %
                            list(args & not_allowed)[0])

    # args need to contain one of -A, -I, -N
    needed = set(["-A", "--append",
                  "-I", "--insert",
                  "-N", "--new-chain"])
    # empty intersection of args and needed, i.e.
    # none from args contains any needed command
    if len(args & needed) == 0:
        raise FirewallError(INVALID_PASSTHROUGH,
                            "no '-A', '-I' or '-N' arg")

class ip4tables(object):
    ipv = "ipv4"
    name = "ip4tables"
    policies_supported = True

    def __init__(self, fw):
        self._fw = fw
        self._command = config.COMMANDS[self.ipv]
        self._restore_command = config.COMMANDS["%s-restore" % self.ipv]
        self.wait_option = self._detect_wait_option()
        self.restore_wait_option = self._detect_restore_wait_option()
        self.fill_exists()
        self.available_tables = []
        self.rich_rule_priority_counts = {}
        self.policy_priority_counts = {}
        self.zone_source_index_cache = []
        self.our_chains = {} # chains created by firewalld

    def fill_exists(self):
        self.command_exists = os.path.exists(self._command)
        self.restore_command_exists = os.path.exists(self._restore_command)

    def __run(self, args):
        # convert to string list
        if self.wait_option and self.wait_option not in args:
            _args = [self.wait_option] + ["%s" % item for item in args]
        else:
            _args = ["%s" % item for item in args]
        log.debug2("%s: %s %s", self.__class__, self._command, " ".join(_args))
        (status, ret) = runProg(self._command, _args)
        if status != 0:
            raise ValueError("'%s %s' failed: %s" % (self._command,
                                                     " ".join(_args), ret))
        return ret

    def _rule_replace(self, rule, pattern, replacement):
        try:
            i = rule.index(pattern)
        except ValueError:
            return False
        else:
            rule[i:i+1] = replacement
            return True

    def is_chain_builtin(self, ipv, table, chain):
        return table in BUILT_IN_CHAINS and \
               chain in BUILT_IN_CHAINS[table]

    def build_chain_rules(self, add, table, chain):
        rule = [ "-t", table ]
        if add:
            rule.append("-N")
        else:
            rule.append("-X")
        rule.append(chain)
        return [rule]

    def build_rule(self, add, table, chain, index, args):
        rule = [ "-t", table ]
        if add:
            rule += [ "-I", chain, str(index) ]
        else:
            rule += [ "-D", chain ]
        rule += args
        return rule

    def reverse_rule(self, args):
        return common_reverse_rule(args)

    def check_passthrough(self, args):
        common_check_passthrough(args)

    def reverse_passthrough(self, args):
        return common_reverse_passthrough(args)

    def passthrough_parse_table_chain(self, args):
        table = "filter"
        try:
            i = args.index("-t")
        except ValueError:
            pass
        else:
            if len(args) >= i+1:
                table = args[i+1]
        chain = None
        for opt in [ "-A", "--append",
                     "-I", "--insert",
                     "-N", "--new-chain" ]:
            try:
                i = args.index(opt)
            except ValueError:
                pass
            else:
                if len(args) >= i+1:
                    chain = args[i+1]
        return (table, chain)

    def _run_replace_zone_source(self, rule, zone_source_index_cache):
        try:
            i = rule.index("%%ZONE_SOURCE%%")
            rule.pop(i)
            zone = rule.pop(i)
            if "-m" == rule[4]: # ipset/mac
                zone_source = (zone, rule[7]) # (zone, address)
            else:
                zone_source = (zone, rule[5]) # (zone, address)
        except ValueError:
            try:
                i = rule.index("%%ZONE_INTERFACE%%")
                rule.pop(i)
                zone_source = None
            except ValueError:
                return

        rule_add = True
        if rule[0] in ["-D", "--delete"]:
            rule_add = False

        if zone_source and not rule_add:
            if zone_source in zone_source_index_cache:
                zone_source_index_cache.remove(zone_source)
        elif rule_add:
            if zone_source:
                # order source based dispatch by zone name
                if zone_source not in zone_source_index_cache:
                    zone_source_index_cache.append(zone_source)
                    zone_source_index_cache.sort(key=lambda x: x[0])

                index = zone_source_index_cache.index(zone_source)
            else:
                if self._fw._allow_zone_drifting:
                    index = 0
                else:
                    index = len(zone_source_index_cache)

            rule[0] = "-I"
            rule.insert(2, "%d" % (index + 1))

    def _set_rule_replace_priority(self, rule, priority_counts, token):
        """
        Change something like
          -t filter -I public_IN %%RICH_RULE_PRIORITY%% 123
        or
          -t filter -A public_IN %%RICH_RULE_PRIORITY%% 321
        into
          -t filter -I public_IN 4
        or
          -t filter -I public_IN
        """
        try:
            i = rule.index(token)
        except ValueError:
            pass
        else:
            rule_add = True
            insert = False
            insert_add_index = -1
            rule.pop(i)
            priority = rule.pop(i)
            if type(priority) != int:
                raise FirewallError(INVALID_RULE, "priority must be followed by a number")

            table = "filter"
            for opt in [ "-t", "--table" ]:
                try:
                    j = rule.index(opt)
                except ValueError:
                    pass
                else:
                    if len(rule) >= j+1:
                        table = rule[j+1]
            for opt in [ "-A", "--append",
                         "-I", "--insert",
                         "-D", "--delete" ]:
                try:
                    insert_add_index = rule.index(opt)
                except ValueError:
                    pass
                else:
                    if len(rule) >= insert_add_index+1:
                        chain = rule[insert_add_index+1]

                    if opt in [ "-I", "--insert" ]:
                        insert = True
                    if opt in [ "-D", "--delete" ]:
                        rule_add = False

            chain = (table, chain)

            # Add the rule to the priority counts. We don't need to store the
            # rule, just bump the ref count for the priority value.
            if not rule_add:
                if chain not in priority_counts or \
                   priority not in priority_counts[chain] or \
                   priority_counts[chain][priority] <= 0:
                    raise FirewallError(UNKNOWN_ERROR, "nonexistent or underflow of priority count")

                priority_counts[chain][priority] -= 1
            else:
                if chain not in priority_counts:
                    priority_counts[chain] = {}
                if priority not in priority_counts[chain]:
                    priority_counts[chain][priority] = 0

                # calculate index of new rule
                index = 1
                for p in sorted(priority_counts[chain].keys()):
                    if p == priority and insert:
                        break
                    index += priority_counts[chain][p]
                    if p == priority:
                        break

                priority_counts[chain][priority] += 1

                rule[insert_add_index] = "-I"
                rule.insert(insert_add_index+2, "%d" % index)

    def set_rules(self, rules, log_denied):
        temp_file = tempFile()

        table_rules = { }
        rich_rule_priority_counts = copy.deepcopy(self.rich_rule_priority_counts)
        policy_priority_counts = copy.deepcopy(self.policy_priority_counts)
        zone_source_index_cache = copy.deepcopy(self.zone_source_index_cache)
        for _rule in rules:
            rule = _rule[:]

            # replace %%REJECT%%
            self._rule_replace(rule, "%%REJECT%%", \
                    ["REJECT", "--reject-with", DEFAULT_REJECT_TYPE[self.ipv]])

            # replace %%ICMP%%
            self._rule_replace(rule, "%%ICMP%%", [ICMP[self.ipv]])

            # replace %%LOGTYPE%%
            try:
                i = rule.index("%%LOGTYPE%%")
            except ValueError:
                pass
            else:
                if log_denied == "off":
                    continue
                if log_denied in [ "unicast", "broadcast", "multicast" ]:
                    rule[i:i+1] = [ "-m", "pkttype", "--pkt-type", log_denied ]
                else:
                    rule.pop(i)

            self._set_rule_replace_priority(rule, rich_rule_priority_counts, "%%RICH_RULE_PRIORITY%%")
            self._set_rule_replace_priority(rule, policy_priority_counts, "%%POLICY_PRIORITY%%")
            self._run_replace_zone_source(rule, zone_source_index_cache)

            table = "filter"
            # get table form rule
            for opt in [ "-t", "--table" ]:
                try:
                    i = rule.index(opt)
                except ValueError:
                    pass
                else:
                    if len(rule) >= i+1:
                        rule.pop(i)
                        table = rule.pop(i)

            # we can not use joinArgs here, because it would use "'" instead
            # of '"' for the start and end of the string, this breaks
            # iptables-restore
            for i in range(len(rule)):
                for c in string.whitespace:
                    if c in rule[i] and not (rule[i].startswith('"') and
                                             rule[i].endswith('"')):
                        rule[i] = '"%s"' % rule[i]

            table_rules.setdefault(table, []).append(rule)

        for table in table_rules:
            rules = table_rules[table]

            temp_file.write("*%s\n" % table)
            for rule in rules:
                temp_file.write(" ".join(rule) + "\n")
            temp_file.write("COMMIT\n")

        temp_file.close()

        stat = os.stat(temp_file.name)
        log.debug2("%s: %s %s", self.__class__, self._restore_command,
                   "%s: %d" % (temp_file.name, stat.st_size))
        args = [ ]
        if self.restore_wait_option:
            args.append(self.restore_wait_option)
        args.append("-n")

        (status, ret) = runProg(self._restore_command, args,
                                stdin=temp_file.name)

        if log.getDebugLogLevel() > 2:
            lines = readfile(temp_file.name)
            if lines is not None:
                i = 1
                for line in lines:
                    log.debug3("%8d: %s" % (i, line), nofmt=1, nl=0)
                    if not line.endswith("\n"):
                        log.debug3("", nofmt=1)
                    i += 1

        os.unlink(temp_file.name)

        if status != 0:
            raise ValueError("'%s %s' failed: %s" % (self._restore_command,
                                                     " ".join(args), ret))
        self.rich_rule_priority_counts = rich_rule_priority_counts
        self.policy_priority_counts = policy_priority_counts
        self.zone_source_index_cache = zone_source_index_cache

    def set_rule(self, rule, log_denied):
        # replace %%REJECT%%
        self._rule_replace(rule, "%%REJECT%%", \
                ["REJECT", "--reject-with", DEFAULT_REJECT_TYPE[self.ipv]])

        # replace %%ICMP%%
        self._rule_replace(rule, "%%ICMP%%", [ICMP[self.ipv]])

        # replace %%LOGTYPE%%
        try:
            i = rule.index("%%LOGTYPE%%")
        except ValueError:
            pass
        else:
            if log_denied == "off":
                return ""
            if log_denied in [ "unicast", "broadcast", "multicast" ]:
                rule[i:i+1] = [ "-m", "pkttype", "--pkt-type", log_denied ]
            else:
                rule.pop(i)

        rich_rule_priority_counts = copy.deepcopy(self.rich_rule_priority_counts)
        policy_priority_counts = copy.deepcopy(self.policy_priority_counts)
        zone_source_index_cache = copy.deepcopy(self.zone_source_index_cache)
        self._set_rule_replace_priority(rule, rich_rule_priority_counts, "%%RICH_RULE_PRIORITY%%")
        self._set_rule_replace_priority(rule, policy_priority_counts, "%%POLICY_PRIORITY%%")
        self._run_replace_zone_source(rule, zone_source_index_cache)

        output = self.__run(rule)

        self.rich_rule_priority_counts = rich_rule_priority_counts
        self.policy_priority_counts = policy_priority_counts
        self.zone_source_index_cache = zone_source_index_cache
        return output

    def get_available_tables(self, table=None):
        ret = []
        tables = [ table ] if table else BUILT_IN_CHAINS.keys()
        for table in tables:
            if table in self.available_tables:
                ret.append(table)
            else:
                try:
                    self.__run(["-t", table, "-L", "-n"])
                    self.available_tables.append(table)
                    ret.append(table)
                except ValueError:
                    log.debug1("%s table '%s' does not exist (or not enough permission to check)." % (self.ipv, table))

        return ret

    def _detect_wait_option(self):
        wait_option = ""
        ret = runProg(self._command, ["-w", "-L", "-n"])  # since iptables-1.4.20
        if ret[0] == 0:
            wait_option = "-w"  # wait for xtables lock
            ret = runProg(self._command, ["-w10", "-L", "-n"])  # since iptables > 1.4.21
            if ret[0] == 0:
                wait_option = "-w10"  # wait max 10 seconds
            log.debug2("%s: %s will be using %s option.", self.__class__, self._command, wait_option)

        return wait_option

    def _detect_restore_wait_option(self):
        temp_file = tempFile()
        temp_file.write("#foo")
        temp_file.close()

        wait_option = ""
        for test_option in ["-w", "--wait=2"]:
            ret = runProg(self._restore_command, [test_option], stdin=temp_file.name)
            if ret[0] == 0 and "invalid option" not in ret[1] \
                           and "unrecognized option" not in ret[1]:
                wait_option = test_option
                break

        log.debug2("%s: %s will be using %s option.", self.__class__, self._restore_command, wait_option)

        os.unlink(temp_file.name)

        return wait_option

    def build_flush_rules(self):
        self.rich_rule_priority_counts = {}
        self.policy_priority_counts = {}
        self.zone_source_index_cache = []
        rules = []
        for table in BUILT_IN_CHAINS.keys():
            if not self.get_available_tables(table):
                continue
            # Flush firewall rules: -F
            # Delete firewall chains: -X
            # Set counter to zero: -Z
            for flag in [ "-F", "-X", "-Z" ]:
                rules.append(["-t", table, flag])
        return rules

    def build_set_policy_rules(self, policy):
        rules = []
        _policy = "DROP" if policy == "PANIC" else policy
        for table in BUILT_IN_CHAINS.keys():
            if not self.get_available_tables(table):
                continue
            if table == "nat":
                continue
            for chain in BUILT_IN_CHAINS[table]:
                rules.append(["-t", table, "-P", chain, _policy])
        return rules

    def supported_icmp_types(self, ipv=None):
        """Return ICMP types that are supported by the iptables/ip6tables command and kernel"""
        ret = [ ]
        output = ""
        try:
            output = self.__run(["-p",
                                 "icmp" if self.ipv == "ipv4" else "ipv6-icmp",
                                 "--help"])
        except ValueError as ex:
            if self.ipv == "ipv4":
                log.debug1("iptables error: %s" % ex)
            else:
                log.debug1("ip6tables error: %s" % ex)
        lines = output.splitlines()

        in_types = False
        for line in lines:
            #print(line)
            if in_types:
                line = line.strip().lower()
                splits = line.split()
                for split in splits:
                    if split.startswith("(") and split.endswith(")"):
                        x = split[1:-1]
                    else:
                        x = split
                    if x not in ret:
                        ret.append(x)
            if self.ipv == "ipv4" and line.startswith("Valid ICMP Types:") or \
               self.ipv == "ipv6" and line.startswith("Valid ICMPv6 Types:"):
                in_types = True
        return ret

    def build_default_tables(self):
        # nothing to do, they always exist
        return []

    def build_default_rules(self, log_denied="off"):
        default_rules = {}

        if self.get_available_tables("security"):
            default_rules["security"] = [ ]
            self.our_chains["security"] = set()
            for chain in BUILT_IN_CHAINS["security"]:
                default_rules["security"].append("-N %s_direct" % chain)
                default_rules["security"].append("-A %s -j %s_direct" % (chain, chain))
                self.our_chains["security"].add("%s_direct" % chain)

        if self.get_available_tables("raw"):
            default_rules["raw"] = [ ]
            self.our_chains["raw"] = set()
            for chain in BUILT_IN_CHAINS["raw"]:
                default_rules["raw"].append("-N %s_direct" % chain)
                default_rules["raw"].append("-A %s -j %s_direct" % (chain, chain))
                self.our_chains["raw"].add("%s_direct" % chain)

                if chain == "PREROUTING":
                    for dispatch_suffix in ["POLICIES_pre", "ZONES_SOURCE", "ZONES", "POLICIES_post"] if self._fw._allow_zone_drifting else ["POLICIES_pre", "ZONES", "POLICIES_post"]:
                        default_rules["raw"].append("-N %s_%s" % (chain, dispatch_suffix))
                        default_rules["raw"].append("-A %s -j %s_%s" % (chain, chain, dispatch_suffix))
                        self.our_chains["raw"].update(set(["%s_%s" % (chain, dispatch_suffix)]))

        if self.get_available_tables("mangle"):
            default_rules["mangle"] = [ ]
            self.our_chains["mangle"] = set()
            for chain in BUILT_IN_CHAINS["mangle"]:
                default_rules["mangle"].append("-N %s_direct" % chain)
                default_rules["mangle"].append("-A %s -j %s_direct" % (chain, chain))
                self.our_chains["mangle"].add("%s_direct" % chain)

                if chain == "PREROUTING":
                    for dispatch_suffix in ["POLICIES_pre", "ZONES_SOURCE", "ZONES", "POLICIES_post"] if self._fw._allow_zone_drifting else ["POLICIES_pre", "ZONES", "POLICIES_post"]:
                        default_rules["mangle"].append("-N %s_%s" % (chain, dispatch_suffix))
                        default_rules["mangle"].append("-A %s -j %s_%s" % (chain, chain, dispatch_suffix))
                        self.our_chains["mangle"].update(set(["%s_%s" % (chain, dispatch_suffix)]))

        if self.get_available_tables("nat"):
            default_rules["nat"] = [ ]
            self.our_chains["nat"] = set()
            for chain in BUILT_IN_CHAINS["nat"]:
                default_rules["nat"].append("-N %s_direct" % chain)
                default_rules["nat"].append("-A %s -j %s_direct" % (chain, chain))
                self.our_chains["nat"].add("%s_direct" % chain)

                if chain in [ "PREROUTING", "POSTROUTING" ]:
                    for dispatch_suffix in ["POLICIES_pre", "ZONES_SOURCE", "ZONES", "POLICIES_post"] if self._fw._allow_zone_drifting else ["POLICIES_pre", "ZONES", "POLICIES_post"]:
                        default_rules["nat"].append("-N %s_%s" % (chain, dispatch_suffix))
                        default_rules["nat"].append("-A %s -j %s_%s" % (chain, chain, dispatch_suffix))
                        self.our_chains["nat"].update(set(["%s_%s" % (chain, dispatch_suffix)]))

        default_rules["filter"] = []
        self.our_chains["filter"] = set()
        default_rules["filter"].append("-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED,DNAT -j ACCEPT")
        default_rules["filter"].append("-A INPUT -i lo -j ACCEPT")
        default_rules["filter"].append("-N INPUT_direct")
        default_rules["filter"].append("-A INPUT -j INPUT_direct")
        self.our_chains["filter"].update(set("INPUT_direct"))
        for dispatch_suffix in ["POLICIES_pre", "ZONES_SOURCE", "ZONES", "POLICIES_post"] if self._fw._allow_zone_drifting else ["POLICIES_pre", "ZONES", "POLICIES_post"]:
            default_rules["filter"].append("-N INPUT_%s" % (dispatch_suffix))
            default_rules["filter"].append("-A INPUT -j INPUT_%s" % (dispatch_suffix))
            self.our_chains["filter"].update(set("INPUT_%s" % (dispatch_suffix)))
        if log_denied != "off":
            default_rules["filter"].append("-A INPUT -m conntrack --ctstate INVALID %%LOGTYPE%% -j LOG --log-prefix 'STATE_INVALID_DROP: '")
        default_rules["filter"].append("-A INPUT -m conntrack --ctstate INVALID -j DROP")
        if log_denied != "off":
            default_rules["filter"].append("-A INPUT %%LOGTYPE%% -j LOG --log-prefix 'FINAL_REJECT: '")
        default_rules["filter"].append("-A INPUT -j %%REJECT%%")

        default_rules["filter"].append("-A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED,DNAT -j ACCEPT")
        default_rules["filter"].append("-A FORWARD -i lo -j ACCEPT")
        default_rules["filter"].append("-N FORWARD_direct")
        default_rules["filter"].append("-A FORWARD -j FORWARD_direct")
        self.our_chains["filter"].update(set("FORWARD_direct"))
        for dispatch_suffix in ["POLICIES_pre"]:
            default_rules["filter"].append("-N FORWARD_%s" % (dispatch_suffix))
            default_rules["filter"].append("-A FORWARD -j FORWARD_%s" % (dispatch_suffix))
            self.our_chains["filter"].update(set("FORWARD_%s" % (dispatch_suffix)))
        for direction in ["IN", "OUT"]:
            for dispatch_suffix in ["ZONES_SOURCE", "ZONES"] if self._fw._allow_zone_drifting else ["ZONES"]:
                default_rules["filter"].append("-N FORWARD_%s_%s" % (direction, dispatch_suffix))
                default_rules["filter"].append("-A FORWARD -j FORWARD_%s_%s" % (direction, dispatch_suffix))
                self.our_chains["filter"].update(set("FORWARD_%s_%s" % (direction, dispatch_suffix)))
        for dispatch_suffix in ["POLICIES_post"]:
            default_rules["filter"].append("-N FORWARD_%s" % (dispatch_suffix))
            default_rules["filter"].append("-A FORWARD -j FORWARD_%s" % (dispatch_suffix))
            self.our_chains["filter"].update(set("FORWARD_%s" % (dispatch_suffix)))
        if log_denied != "off":
            default_rules["filter"].append("-A FORWARD -m conntrack --ctstate INVALID %%LOGTYPE%% -j LOG --log-prefix 'STATE_INVALID_DROP: '")
        default_rules["filter"].append("-A FORWARD -m conntrack --ctstate INVALID -j DROP")
        if log_denied != "off":
            default_rules["filter"].append("-A FORWARD %%LOGTYPE%% -j LOG --log-prefix 'FINAL_REJECT: '")
        default_rules["filter"].append("-A FORWARD -j %%REJECT%%")

        default_rules["filter"] += [
            "-N OUTPUT_direct",

            "-A OUTPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT",
            "-A OUTPUT -o lo -j ACCEPT",
            "-A OUTPUT -j OUTPUT_direct",
        ]
        self.our_chains["filter"].update(set("OUTPUT_direct"))
        for dispatch_suffix in ["POLICIES_pre"]:
            default_rules["filter"].append("-N OUTPUT_%s" % (dispatch_suffix))
            default_rules["filter"].append("-A OUTPUT -j OUTPUT_%s" % (dispatch_suffix))
            self.our_chains["filter"].update(set("OUTPUT_%s" % (dispatch_suffix)))
        for dispatch_suffix in ["POLICIES_post"]:
            default_rules["filter"].append("-N OUTPUT_%s" % (dispatch_suffix))
            default_rules["filter"].append("-A OUTPUT -j OUTPUT_%s" % (dispatch_suffix))
            self.our_chains["filter"].update(set("OUTPUT_%s" % (dispatch_suffix)))

        final_default_rules = []
        for table in default_rules:
            if table not in self.get_available_tables():
                continue
            for rule in default_rules[table]:
                final_default_rules.append(["-t", table] + splitArgs(rule))

        return final_default_rules

    def get_zone_table_chains(self, table):
        if table == "filter":
            return { "INPUT", "FORWARD_IN", "FORWARD_OUT" }
        if table == "mangle":
            if "mangle" in self.get_available_tables():
                return { "PREROUTING" }
        if table == "nat":
            if "nat" in self.get_available_tables():
                return { "PREROUTING", "POSTROUTING" }
        if table == "raw":
            if "raw" in self.get_available_tables():
                return { "PREROUTING" }

        return {}

    def build_policy_ingress_egress_rules(self, enable, policy, table, chain,
                                          ingress_interfaces, egress_interfaces,
                                          ingress_sources, egress_sources):
        p_obj = self._fw.policy.get_policy(policy)
        chain_suffix = "pre" if p_obj.priority < 0 else "post"
        isSNAT = True if (table == "nat" and chain == "POSTROUTING") else False
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX, isSNAT)

        ingress_fragments = []
        egress_fragments = []
        for interface in ingress_interfaces:
            ingress_fragments.append(["-i", interface])
        for interface in egress_interfaces:
            egress_fragments.append(["-o", interface])
        for addr in ingress_sources:
            ipv = self._fw.zone.check_source(addr)
            if ipv in ["ipv4", "ipv6"] and not self.is_ipv_supported(ipv):
                continue
            ingress_fragments.append(self._rule_addr_fragment("-s", addr))
        for addr in egress_sources:
            ipv = self._fw.zone.check_source(addr)
            if ipv in ["ipv4", "ipv6"] and not self.is_ipv_supported(ipv):
                continue
            # iptables can not match destination MAC
            if check_mac(addr) and chain in ["POSTROUTING", "FORWARD_OUT", "OUTPUT"]:
                continue

            egress_fragments.append(self._rule_addr_fragment("-d", addr))

        def _generate_policy_dispatch_rule(ingress_fragment, egress_fragment):
            add_del = {True: "-A", False: "-D" }[enable]
            rule = ["-t", table, add_del, "%s_POLICIES_%s" % (chain, chain_suffix),
                    "%%POLICY_PRIORITY%%", p_obj.priority]
            if ingress_fragment:
                rule.extend(ingress_fragment)
            if egress_fragment:
                rule.extend(egress_fragment)
            rule.extend(["-j", _policy])

            return rule

        rules = []
        if ingress_fragments:
            # zone --> [zone, ANY, HOST]
            for ingress_fragment in ingress_fragments:
                # zone --> zone
                if egress_fragments:
                    for egress_fragment in egress_fragments:
                        rules.append(_generate_policy_dispatch_rule(ingress_fragment, egress_fragment))
                elif egress_sources:
                    # if the egress source is not for the current family (there
                    # are no egress fragments), then avoid creating an invalid
                    # catch all rule.
                    pass
                else:
                    rules.append(_generate_policy_dispatch_rule(ingress_fragment, None))
        elif ingress_sources:
            # if the ingress source is not for the current family (there are no
            # ingress fragments), then avoid creating an invalid catch all
            # rule.
            pass
        else: # [ANY, HOST] --> [zone, ANY, HOST]
            # [ANY, HOST] --> zone
            if egress_fragments:
                for egress_fragment in egress_fragments:
                    rules.append(_generate_policy_dispatch_rule(None, egress_fragment))
            elif egress_sources:
                # if the egress source is not for the current family (there
                # are no egress fragments), then avoid creating an invalid
                # catch all rule.
                pass
            else:
                # [ANY, HOST] --> [ANY, HOST]
                rules.append(_generate_policy_dispatch_rule(None, None))

        return rules

    def build_zone_source_interface_rules(self, enable, zone, policy, interface,
                                          table, chain, append=False):
        isSNAT = True if (table == "nat" and chain == "POSTROUTING") else False
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX, isSNAT=isSNAT)
        opt = {
            "PREROUTING": "-i",
            "POSTROUTING": "-o",
            "INPUT": "-i",
            "FORWARD_IN": "-i",
            "FORWARD_OUT": "-o",
            "OUTPUT": "-o",
        }[chain]

        action = "-g"

        if enable and not append:
            rule = [ "-I", "%s_ZONES" % chain, "%%ZONE_INTERFACE%%" ]
        elif enable:
            rule = [ "-A", "%s_ZONES" % chain ]
        else:
            rule = [ "-D", "%s_ZONES" % chain ]
            if not append:
                rule += ["%%ZONE_INTERFACE%%"]
        rule += [ "-t", table, opt, interface, action, _policy ]
        return [rule]

    def _rule_addr_fragment(self, opt, address, invert=False):
        if address.startswith("ipset:"):
            name = address[6:]
            if opt == "-d":
                opt = "dst"
            else:
                opt = "src"
            flags = ",".join([opt] * self._fw.ipset.get_dimension(name))
            return ["-m", "set", "--match-set", name, flags]
        elif check_mac(address):
            # outgoing can not be set
            if opt == "-d":
                raise FirewallError(INVALID_ADDR, "Can't match a destination MAC.")
            return ["-m", "mac", "--mac-source", address.upper()]
        else:
            if check_single_address("ipv6", address):
                address = normalizeIP6(address)
            elif check_address("ipv6", address):
                addr_split = address.split("/")
                address = normalizeIP6(addr_split[0]) + "/" + addr_split[1]
            return [opt, address]

    def build_zone_source_address_rules(self, enable, zone, policy,
                                        address, table, chain):
        add_del = { True: "-I", False: "-D" }[enable]

        isSNAT = True if (table == "nat" and chain == "POSTROUTING") else False
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX, isSNAT=isSNAT)
        opt = {
            "PREROUTING": "-s",
            "POSTROUTING": "-d",
            "INPUT": "-s",
            "FORWARD_IN": "-s",
            "FORWARD_OUT": "-d",
            "OUTPUT": "-d",
        }[chain]

        if self._fw._allow_zone_drifting:
            zone_dispatch_chain = "%s_ZONES_SOURCE" % (chain)
        else:
            zone_dispatch_chain = "%s_ZONES" % (chain)

        # iptables can not match destination MAC
        if check_mac(address) and chain in ["POSTROUTING", "FORWARD_OUT", "OUTPUT"]:
            return []

        rule = [add_del, zone_dispatch_chain, "%%ZONE_SOURCE%%", zone, "-t", table]
        rule.extend(self._rule_addr_fragment(opt, address))
        rule.extend(["-g", _policy])

        return [rule]

    def build_policy_chain_rules(self, enable, policy, table, chain):
        add_del_chain = { True: "-N", False: "-X" }[enable]
        add_del_rule = { True: "-A", False: "-D" }[enable]
        isSNAT = True if (table == "nat" and chain == "POSTROUTING") else False
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX, isSNAT=isSNAT)

        self.our_chains[table].update(set([_policy,
                                      "%s_log" % _policy,
                                      "%s_deny" % _policy,
                                      "%s_pre" % _policy,
                                      "%s_post" % _policy,
                                      "%s_allow" % _policy]))

        rules = []
        rules.append([ add_del_chain, _policy, "-t", table ])
        rules.append([ add_del_chain, "%s_pre" % _policy, "-t", table ])
        rules.append([ add_del_chain, "%s_log" % _policy, "-t", table ])
        rules.append([ add_del_chain, "%s_deny" % _policy, "-t", table ])
        rules.append([ add_del_chain, "%s_allow" % _policy, "-t", table ])
        rules.append([ add_del_chain, "%s_post" % _policy, "-t", table ])
        rules.append([ add_del_rule, _policy, "-t", table, "-j", "%s_pre" % _policy ])
        rules.append([ add_del_rule, _policy, "-t", table, "-j", "%s_log" % _policy ])
        rules.append([ add_del_rule, _policy, "-t", table, "-j", "%s_deny" % _policy ])
        rules.append([ add_del_rule, _policy, "-t", table, "-j", "%s_allow" % _policy ])
        rules.append([ add_del_rule, _policy, "-t", table, "-j", "%s_post" % _policy ])

        target = self._fw.policy._policies[policy].target

        if self._fw.get_log_denied() != "off":
            if table == "filter":
                if target in [ "REJECT", "%%REJECT%%" ]:
                    rules.append([ add_del_rule, _policy, "-t", table, "%%LOGTYPE%%",
                                   "-j", "LOG", "--log-prefix",
                                   "\"%s_REJECT: \"" % _policy ])
                if target == "DROP":
                    rules.append([ add_del_rule, _policy, "-t", table, "%%LOGTYPE%%",
                                   "-j", "LOG", "--log-prefix",
                                   "\"%s_DROP: \"" % _policy ])

        if table == "filter" and \
           target in [ "ACCEPT", "REJECT", "%%REJECT%%", "DROP" ]:
            rules.append([ add_del_rule, _policy, "-t", table, "-j", target ])

        if not enable:
            rules.reverse()

        return rules

    def _rule_limit(self, limit):
        if not limit:
            return []
        s = ["-m", "limit", "--limit", limit.value]
        if limit.burst is not None:
            s += ["--limit-burst", limit.burst]
        return s

    def _rich_rule_chain_suffix(self, rich_rule):
        if type(rich_rule.element) in [Rich_Masquerade, Rich_ForwardPort, Rich_IcmpBlock]:
            # These are special and don't have an explicit action
            pass
        elif rich_rule.action:
            if type(rich_rule.action) not in [Rich_Accept, Rich_Reject, Rich_Drop, Rich_Mark]:
                raise FirewallError(INVALID_RULE, "Unknown action %s" % type(rich_rule.action))
        else:
            raise FirewallError(INVALID_RULE, "No rule action specified.")

        if rich_rule.priority == 0:
            if type(rich_rule.element) in [Rich_Masquerade, Rich_ForwardPort] or \
               type(rich_rule.action) in [Rich_Accept, Rich_Mark]:
                return "allow"
            elif type(rich_rule.element) in [Rich_IcmpBlock] or \
                 type(rich_rule.action) in [Rich_Reject, Rich_Drop]:
                return "deny"
        elif rich_rule.priority < 0:
            return "pre"
        else:
            return "post"

    def _rich_rule_chain_suffix_from_log(self, rich_rule):
        if not rich_rule.log and not rich_rule.audit:
            raise FirewallError(INVALID_RULE, "Not log or audit")

        if rich_rule.priority == 0:
            return "log"
        elif rich_rule.priority < 0:
            return "pre"
        else:
            return "post"

    def _rich_rule_priority_fragment(self, rich_rule):
        if rich_rule.priority == 0:
            return []
        return ["%%RICH_RULE_PRIORITY%%", rich_rule.priority]

    def _rich_rule_log(self, policy, rich_rule, enable, table, rule_fragment):
        if not rich_rule.log:
            return []

        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        add_del = { True: "-A", False: "-D" }[enable]

        chain_suffix = self._rich_rule_chain_suffix_from_log(rich_rule)
        rule = ["-t", table, add_del, "%s_%s" % (_policy, chain_suffix)]
        rule += self._rich_rule_priority_fragment(rich_rule)
        rule += rule_fragment + [ "-j", "LOG" ]
        if rich_rule.log.prefix:
            rule += [ "--log-prefix", "'%s'" % rich_rule.log.prefix ]
        if rich_rule.log.level:
            rule += [ "--log-level", "%s" % rich_rule.log.level ]
        rule += self._rule_limit(rich_rule.log.limit)

        return rule

    def _rich_rule_audit(self, policy, rich_rule, enable, table, rule_fragment):
        if not rich_rule.audit:
            return []

        add_del = { True: "-A", False: "-D" }[enable]

        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        chain_suffix = self._rich_rule_chain_suffix_from_log(rich_rule)
        rule = ["-t", table, add_del, "%s_%s" % (_policy, chain_suffix)]
        rule += self._rich_rule_priority_fragment(rich_rule)
        rule += rule_fragment
        if type(rich_rule.action) == Rich_Accept:
            _type = "accept"
        elif type(rich_rule.action) == Rich_Reject:
            _type = "reject"
        elif type(rich_rule.action) ==  Rich_Drop:
            _type = "drop"
        else:
            _type = "unknown"
        rule += [ "-j", "AUDIT", "--type", _type ]
        rule += self._rule_limit(rich_rule.audit.limit)

        return rule

    def _rich_rule_action(self, policy, rich_rule, enable, table, rule_fragment):
        if not rich_rule.action:
            return []

        add_del = { True: "-A", False: "-D" }[enable]

        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        chain_suffix = self._rich_rule_chain_suffix(rich_rule)
        chain = "%s_%s" % (_policy, chain_suffix)
        if type(rich_rule.action) == Rich_Accept:
            rule_action = [ "-j", "ACCEPT" ]
        elif type(rich_rule.action) == Rich_Reject:
            rule_action = [ "-j", "REJECT" ]
            if rich_rule.action.type:
                rule_action += [ "--reject-with", rich_rule.action.type ]
        elif type(rich_rule.action) ==  Rich_Drop:
            rule_action = [ "-j", "DROP" ]
        elif type(rich_rule.action) == Rich_Mark:
            table = "mangle"
            _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
            chain = "%s_%s" % (_policy, chain_suffix)
            rule_action = [ "-j", "MARK", "--set-xmark", rich_rule.action.set ]
        else:
            raise FirewallError(INVALID_RULE,
                                "Unknown action %s" % type(rich_rule.action))

        rule = ["-t", table, add_del, chain]
        rule += self._rich_rule_priority_fragment(rich_rule)
        rule += rule_fragment + rule_action
        rule += self._rule_limit(rich_rule.action.limit)

        return rule

    def _rich_rule_destination_fragment(self, rich_dest):
        if not rich_dest:
            return []

        rule_fragment = []
        if rich_dest.addr:
            if rich_dest.invert:
                rule_fragment.append("!")
            if check_single_address("ipv6", rich_dest.addr):
                rule_fragment += [ "-d", normalizeIP6(rich_dest.addr) ]
            elif check_address("ipv6", rich_dest.addr):
                addr_split = rich_dest.addr.split("/")
                rule_fragment += [ "-d", normalizeIP6(addr_split[0]) + "/" + addr_split[1] ]
            else:
                rule_fragment += [ "-d", rich_dest.addr ]
        elif rich_dest.ipset:
            rule_fragment += [ "-m", "set" ]
            if rich_dest.invert:
                rule_fragment.append("!")
            flags = self._fw.zone._ipset_match_flags(rich_dest.ipset, "dst")
            rule_fragment += [ "--match-set", rich_dest.ipset, flags ]

        return rule_fragment

    def _rich_rule_source_fragment(self, rich_source):
        if not rich_source:
            return []

        rule_fragment = []
        if rich_source.addr:
            if rich_source.invert:
                rule_fragment.append("!")
            if check_single_address("ipv6", rich_source.addr):
                rule_fragment += [ "-s", normalizeIP6(rich_source.addr) ]
            elif check_address("ipv6", rich_source.addr):
                addr_split = rich_source.addr.split("/")
                rule_fragment += [ "-s", normalizeIP6(addr_split[0]) + "/" + addr_split[1] ]
            else:
                rule_fragment += [ "-s", rich_source.addr ]
        elif hasattr(rich_source, "mac") and rich_source.mac:
            rule_fragment += [ "-m", "mac" ]
            if rich_source.invert:
                rule_fragment.append("!")
            rule_fragment += [ "--mac-source", rich_source.mac ]
        elif hasattr(rich_source, "ipset") and rich_source.ipset:
            rule_fragment += [ "-m", "set" ]
            if rich_source.invert:
                rule_fragment.append("!")
            flags = self._fw.zone._ipset_match_flags(rich_source.ipset, "src")
            rule_fragment += [ "--match-set", rich_source.ipset, flags ]

        return rule_fragment

    def build_policy_ports_rules(self, enable, policy, proto, port, destination=None, rich_rule=None):
        add_del = { True: "-A", False: "-D" }[enable]
        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        rule_fragment = [ "-p", proto ]
        if port:
            rule_fragment += [ "--dport", "%s" % portStr(port) ]
        if destination:
            rule_fragment += [ "-d", destination ]
        if rich_rule:
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        if not rich_rule or type(rich_rule.action) != Rich_Mark:
            rule_fragment += [ "-m", "conntrack", "--ctstate", "NEW,UNTRACKED" ]

        rules = []
        if rich_rule:
            rules.append(self._rich_rule_log(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_audit(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_action(policy, rich_rule, enable, table, rule_fragment))
        else:
            rules.append([add_del, "%s_allow" % (_policy), "-t", table] +
                         rule_fragment + [ "-j", "ACCEPT" ])

        return rules

    def build_policy_protocol_rules(self, enable, policy, protocol, destination=None, rich_rule=None):
        add_del = { True: "-A", False: "-D" }[enable]
        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        rule_fragment = [ "-p", protocol ]
        if destination:
            rule_fragment += [ "-d", destination ]
        if rich_rule:
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        if not rich_rule or type(rich_rule.action) != Rich_Mark:
            rule_fragment += [ "-m", "conntrack", "--ctstate", "NEW,UNTRACKED" ]

        rules = []
        if rich_rule:
            rules.append(self._rich_rule_log(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_audit(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_action(policy, rich_rule, enable, table, rule_fragment))
        else:
            rules.append([add_del, "%s_allow" % (_policy), "-t", table] +
                         rule_fragment + [ "-j", "ACCEPT" ])

        return rules

    def build_policy_source_ports_rules(self, enable, policy, proto, port,
                                     destination=None, rich_rule=None):
        add_del = { True: "-A", False: "-D" }[enable]
        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        rule_fragment = [ "-p", proto ]
        if port:
            rule_fragment += [ "--sport", "%s" % portStr(port) ]
        if destination:
            rule_fragment += [ "-d", destination ]
        if rich_rule:
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        if not rich_rule or type(rich_rule.action) != Rich_Mark:
            rule_fragment += [ "-m", "conntrack", "--ctstate", "NEW,UNTRACKED" ]

        rules = []
        if rich_rule:
            rules.append(self._rich_rule_log(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_audit(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_action(policy, rich_rule, enable, table, rule_fragment))
        else:
            rules.append([add_del, "%s_allow" % (_policy), "-t", table] +
                         rule_fragment + [ "-j", "ACCEPT" ])

        return rules

    def build_policy_helper_ports_rules(self, enable, policy, proto, port,
                                      destination, helper_name, module_short_name):
        table = "raw"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
        add_del = { True: "-A", False: "-D" }[enable]

        rule = [ add_del, "%s_allow" % (_policy), "-t", "raw", "-p", proto ]
        if port:
            rule += [ "--dport", "%s" % portStr(port) ]
        if destination:
            rule += [ "-d",  destination ]
        rule += [ "-j", "CT", "--helper", module_short_name ]

        return [rule]

    def build_zone_forward_rules(self, enable, zone, policy, table, interface=None, source=None):
        add_del = { True: "-A", False: "-D" }[enable]
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        rules = []
        if interface:
            rules.append(["-t", "filter", add_del, "%s_allow" % _policy,
                          "-o", interface, "-j", "ACCEPT"])
        else: # source
            # iptables can not match destination MAC
            if check_mac(source):
                return []

            rules.append(["-t", "filter", add_del, "%s_allow" % _policy]
                         + self._rule_addr_fragment("-d", source) +
                         ["-j", "ACCEPT"])
        return rules

    def build_policy_masquerade_rules(self, enable, policy, rich_rule=None):
        table = "nat"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX, isSNAT=True)

        add_del = { True: "-A", False: "-D" }[enable]

        rule_fragment = []
        if rich_rule:
            chain_suffix = self._rich_rule_chain_suffix(rich_rule)
            rule_fragment += self._rich_rule_priority_fragment(rich_rule)
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        else:
            chain_suffix = "allow"

        rules = []
        rules.append(["-t", "nat", add_del, "%s_%s" % (_policy, chain_suffix)]
                     + rule_fragment +
                     [ "!", "-o", "lo", "-j", "MASQUERADE" ])

        rule_fragment = []
        if rich_rule:
            chain_suffix = self._rich_rule_chain_suffix(rich_rule)
            rule_fragment += self._rich_rule_priority_fragment(rich_rule)
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        else:
            chain_suffix = "allow"

        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
        rules.append(["-t", "filter", add_del, "%s_%s" % (_policy, chain_suffix)]
                     + rule_fragment +
                     ["-m", "conntrack", "--ctstate", "NEW,UNTRACKED", "-j", "ACCEPT" ])

        return rules

    def build_policy_forward_port_rules(self, enable, policy, port,
                                      protocol, toport, toaddr, rich_rule=None):
        table = "nat"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
        add_del = { True: "-A", False: "-D" }[enable]

        to = ""
        if toaddr:
            if check_single_address("ipv6", toaddr):
                to += "[%s]" % normalizeIP6(toaddr)
            else:
                to += toaddr
        if toport and toport != "":
            to += ":%s" % portStr(toport, "-")

        rule_fragment = []
        if rich_rule:
            chain_suffix = self._rich_rule_chain_suffix(rich_rule)
            rule_fragment = self._rich_rule_priority_fragment(rich_rule)
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        else:
            chain_suffix = "allow"

        rules = []
        if rich_rule:
            rules.append(self._rich_rule_log(policy, rich_rule, enable, "nat", rule_fragment))
        rules.append(["-t", "nat", add_del, "%s_%s" % (_policy, chain_suffix)]
                     + rule_fragment +
                     ["-p", protocol, "--dport", portStr(port),
                      "-j", "DNAT", "--to-destination", to])

        return rules

    def build_policy_icmp_block_rules(self, enable, policy, ict, rich_rule=None):
        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)
        add_del = { True: "-A", False: "-D" }[enable]

        if self.ipv == "ipv4":
            proto = [ "-p", "icmp" ]
            match = [ "-m", "icmp", "--icmp-type", ict.name ]
        else:
            proto = [ "-p", "ipv6-icmp" ]
            match = [ "-m", "icmp6", "--icmpv6-type", ict.name ]

        rules = []
        if self._fw.policy.query_icmp_block_inversion(policy):
            final_chain = "%s_allow" % (_policy)
            final_target = "ACCEPT"
        else:
            final_chain = "%s_deny" % (_policy)
            final_target = "%%REJECT%%"

        rule_fragment = []
        if rich_rule:
            rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
            rule_fragment += self._rich_rule_source_fragment(rich_rule.source)
        rule_fragment += proto + match

        if rich_rule:
            rules.append(self._rich_rule_log(policy, rich_rule, enable, table, rule_fragment))
            rules.append(self._rich_rule_audit(policy, rich_rule, enable, table, rule_fragment))
            if rich_rule.action:
                rules.append(self._rich_rule_action(policy, rich_rule, enable, table, rule_fragment))
            else:
                chain_suffix = self._rich_rule_chain_suffix(rich_rule)
                rules.append(["-t", table, add_del, "%s_%s" % (_policy, chain_suffix)]
                             + self._rich_rule_priority_fragment(rich_rule)
                             + rule_fragment +
                             [ "-j", "%%REJECT%%" ])
        else:
            if self._fw.get_log_denied() != "off" and final_target != "ACCEPT":
                rules.append([ add_del, final_chain, "-t", table ]
                             + rule_fragment +
                             [ "%%LOGTYPE%%", "-j", "LOG",
                               "--log-prefix", "\"%s_ICMP_BLOCK: \"" % policy ])
            rules.append([ add_del, final_chain, "-t", table ]
                         + rule_fragment +
                         [ "-j", final_target ])

        return rules

    def build_policy_icmp_block_inversion_rules(self, enable, policy):
        table = "filter"
        _policy = self._fw.policy.policy_base_chain_name(policy, table, POLICY_CHAIN_PREFIX)

        rules = []
        rule_idx = 6

        if self._fw.policy.query_icmp_block_inversion(policy):
            ibi_target = "%%REJECT%%"

            if self._fw.get_log_denied() != "off":
                if enable:
                    rule = [ "-I", _policy, str(rule_idx) ]
                else:
                    rule = [ "-D", _policy ]

                rule = rule + [ "-t", table, "-p", "%%ICMP%%",
                              "%%LOGTYPE%%",
                              "-j", "LOG", "--log-prefix",
                              "\"%s_ICMP_BLOCK: \"" % _policy ]
                rules.append(rule)
                rule_idx += 1
        else:
            ibi_target = "ACCEPT"

        if enable:
            rule = [ "-I", _policy, str(rule_idx) ]
        else:
            rule = [ "-D", _policy ]
        rule = rule + [ "-t", table, "-p", "%%ICMP%%", "-j", ibi_target ]
        rules.append(rule)

        return rules

    def build_policy_rich_source_destination_rules(self, enable, policy, rich_rule):
        table = "filter"

        rule_fragment = []
        rule_fragment += self._rich_rule_destination_fragment(rich_rule.destination)
        rule_fragment += self._rich_rule_source_fragment(rich_rule.source)

        rules = []
        rules.append(self._rich_rule_log(policy, rich_rule, enable, table, rule_fragment))
        rules.append(self._rich_rule_audit(policy, rich_rule, enable, table, rule_fragment))
        rules.append(self._rich_rule_action(policy, rich_rule, enable, table, rule_fragment))

        return rules

    def is_ipv_supported(self, ipv):
        return ipv == self.ipv

class ip6tables(ip4tables):
    ipv = "ipv6"
    name = "ip6tables"

    def build_rpfilter_rules(self, log_denied=False):
        rules = []
        rules.append([ "-I", "PREROUTING", "-t", "mangle",
                       "-m", "rpfilter", "--invert", "--validmark",
                       "-j", "DROP" ])
        if log_denied != "off":
            rules.append([ "-I", "PREROUTING", "-t", "mangle",
                           "-m", "rpfilter", "--invert", "--validmark",
                           "-j", "LOG",
                           "--log-prefix", "rpfilter_DROP: " ])
        rules.append([ "-I", "PREROUTING", "-t", "mangle",
                       "-p", "ipv6-icmp",
                       "--icmpv6-type=neighbour-solicitation",
                       "-j", "ACCEPT" ]) # RHBZ#1575431, kernel bug in 4.16-4.17
        rules.append([ "-I", "PREROUTING", "-t", "mangle",
                       "-p", "ipv6-icmp",
                       "--icmpv6-type=router-advertisement",
                       "-j", "ACCEPT" ]) # RHBZ#1058505
        return rules

    def build_rfc3964_ipv4_rules(self):
        daddr_list = [
                     "::0.0.0.0/96", # IPv4 compatible
                     "::ffff:0.0.0.0/96", # IPv4 mapped
                     "2002:0000::/24", # 0.0.0.0/8 (the system has no address assigned yet)
                     "2002:0a00::/24", # 10.0.0.0/8 (private)
                     "2002:7f00::/24", # 127.0.0.0/8 (loopback)
                     "2002:ac10::/28", # 172.16.0.0/12 (private)
                     "2002:c0a8::/32", # 192.168.0.0/16 (private)
                     "2002:a9fe::/32", # 169.254.0.0/16 (IANA Assigned DHCP link-local)
                     "2002:e000::/19", # 224.0.0.0/4 (multicast), 240.0.0.0/4 (reserved and broadcast)
                     ]

        chain_name = "RFC3964_IPv4"
        self.our_chains["filter"].add(chain_name)

        rules = []
        rules.append(["-t", "filter", "-N", chain_name])
        for daddr in daddr_list:
            rules.append(["-t", "filter", "-I", chain_name,
                          "-d", daddr, "-j", "REJECT", "--reject-with",
                          "addr-unreach"])
            if self._fw._log_denied in ["unicast", "all"]:
                rules.append(["-t", "filter", "-I", chain_name,
                              "-d", daddr, "-j", "LOG",
                              "--log-prefix", "\"RFC3964_IPv4_REJECT: \""])

        # Inject into FORWARD and OUTPUT chains
        rules.append(["-t", "filter", "-I", "OUTPUT", "4",
                      "-j", chain_name])
        rules.append(["-t", "filter", "-I", "FORWARD", "4",
                      "-j", chain_name])
        return rules
