# SPDX-License-Identifier: GPL-2.0-or-later
#
# Copyright (C) 2015-2016 Red Hat, Inc.
#
# Authors:
# Thomas Woerner <twoerner@redhat.com>

"""ipset io XML handler, reader, writer"""

import xml.sax as sax
import os
import io
import shutil

from firewall import config
from firewall.functions import (
    checkIP,
    checkIP6,
    checkIPnMask,
    checkIP6nMask,
    check_mac,
    check_port,
    checkInterface,
    checkProtocol,
)
from firewall.core.io.io_object import (
    IO_Object,
    IO_Object_ContentHandler,
    IO_Object_XMLGenerator,
)
from firewall.core.ipset import IPSET_TYPES, IPSET_CREATE_OPTIONS
from firewall.core.icmp import (
    check_icmp_name,
    check_icmp_type_code,
    check_icmpv6_name,
    check_icmpv6_type_code,
)
from firewall.core.logger import log
from firewall import errors
from firewall.errors import FirewallError


class IPSet(IO_Object):
    IMPORT_EXPORT_STRUCTURE = {
        "version": "",  # s
        "short": "",  # s
        "description": "",  # s
        "type": "",  # s
        "options": {"": ""},  # a{ss}
        "entries": [""],  # as
    }
    DBUS_SIGNATURE = "(ssssa{ss}as)"
    ADDITIONAL_ALNUM_CHARS = ["_", "-", ":", "."]
    PARSER_REQUIRED_ELEMENT_ATTRS = {
        "short": None,
        "description": None,
        "ipset": ["type"],
        "option": ["name"],
        "entry": None,
    }
    PARSER_OPTIONAL_ELEMENT_ATTRS = {
        "ipset": ["version"],
        "option": ["value"],
    }

    def __init__(self):
        super(IPSet, self).__init__()
        self.version = ""
        self.short = ""
        self.description = ""
        self.type = ""
        self.entries = []
        self.options = {}
        self.applied = False

    def cleanup(self):
        self.version = ""
        self.short = ""
        self.description = ""
        self.type = ""
        del self.entries[:]
        self.options.clear()
        self.applied = False

    @staticmethod
    def check_entry(entry, options, ipset_type):
        family = "ipv4"
        if "family" in options:
            if options["family"] == "inet6":
                family = "ipv6"

        if not ipset_type.startswith("hash:"):
            raise FirewallError(
                errors.INVALID_IPSET, "ipset type '%s' not usable" % ipset_type
            )
        flags = ipset_type[5:].split(",")
        items = entry.split(",")

        if len(flags) != len(items) or len(flags) < 1:
            raise FirewallError(
                errors.INVALID_ENTRY,
                "entry '%s' does not match ipset type '%s'" % (entry, ipset_type),
            )

        for i, flag in enumerate(flags):
            item = items[i]

            if flag == "ip":
                if "-" in item and family == "ipv4":
                    # IP ranges only with plain IPs, no masks
                    if i > 1:
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address '%s' in '%s'[%d]" % (item, entry, i),
                        )
                    splits = item.split("-")
                    if len(splits) != 2:
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address range '%s' in '%s' for %s (%s)"
                            % (item, entry, ipset_type, family),
                        )
                    for _split in splits:
                        if (family == "ipv4" and not checkIP(_split)) or (
                            family == "ipv6" and not checkIP6(_split)
                        ):
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid address '%s' in '%s' for %s (%s)"
                                % (_split, entry, ipset_type, family),
                            )
                else:
                    # IPs with mask only allowed in the first
                    # position of the type
                    if family == "ipv4":
                        if item == "0.0.0.0":
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid address '%s' in '%s' for %s (%s)"
                                % (item, entry, ipset_type, family),
                            )
                        if i == 0:
                            ip_check = checkIPnMask
                        else:
                            ip_check = checkIP
                    else:
                        ip_check = checkIP6
                    if not ip_check(item):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address '%s' in '%s' for %s (%s)"
                            % (item, entry, ipset_type, family),
                        )
            elif flag == "net":
                if "-" in item:
                    # IP ranges only with plain IPs, no masks
                    splits = item.split("-")
                    if len(splits) != 2:
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address range '%s' in '%s' for %s (%s)"
                            % (item, entry, ipset_type, family),
                        )
                    # First part can only be a plain IP
                    if (family == "ipv4" and not checkIP(splits[0])) or (
                        family == "ipv6" and not checkIP6(splits[0])
                    ):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address '%s' in '%s' for %s (%s)"
                            % (splits[0], entry, ipset_type, family),
                        )
                    # Second part can also have a mask
                    if (family == "ipv4" and not checkIPnMask(splits[1])) or (
                        family == "ipv6" and not checkIP6nMask(splits[1])
                    ):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address '%s' in '%s' for %s (%s)"
                            % (splits[1], entry, ipset_type, family),
                        )
                else:
                    # IPs with mask allowed in all positions, but no /0
                    if item.endswith("/0"):
                        if not (
                            family == "ipv6"
                            and i == 0
                            and ipset_type == "hash:net,iface"
                        ):
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid address '%s' in '%s' for %s (%s)"
                                % (item, entry, ipset_type, family),
                            )
                    if (family == "ipv4" and not checkIPnMask(item)) or (
                        family == "ipv6" and not checkIP6nMask(item)
                    ):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid address '%s' in '%s' for %s (%s)"
                            % (item, entry, ipset_type, family),
                        )
            elif flag == "mac":
                # ipset does not allow to add 00:00:00:00:00:00
                if not check_mac(item) or item == "00:00:00:00:00:00":
                    raise FirewallError(
                        errors.INVALID_ENTRY,
                        "invalid mac address '%s' in '%s'" % (item, entry),
                    )
            elif flag == "port":
                if ":" in item:
                    splits = item.split(":")
                    if len(splits) != 2:
                        raise FirewallError(
                            errors.INVALID_ENTRY, "invalid port '%s'" % (item)
                        )
                    if splits[0] == "icmp":
                        if family != "ipv4":
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid protocol for family '%s' in '%s'"
                                % (family, entry),
                            )
                        if not check_icmp_name(splits[1]) and "/" not in splits[1]:
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid icmp type '%s' in '%s'" % (splits[1], entry),
                            )
                        else:
                            (_type, _code) = splits[1].split("/")
                            if not check_icmp_type_code(_type, _code):
                                raise FirewallError(
                                    errors.INVALID_ENTRY,
                                    "invalid icmp type '%s' in '%s'"
                                    % (splits[1], entry),
                                )
                    elif splits[0] in ["icmpv6", "ipv6-icmp"]:
                        if family != "ipv6":
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid protocol for family '%s' in '%s'"
                                % (family, entry),
                            )
                        if not check_icmpv6_name(splits[1]) and "/" not in splits[1]:
                            raise FirewallError(
                                errors.INVALID_ENTRY,
                                "invalid icmpv6 type '%s' in '%s'" % (splits[1], entry),
                            )
                        else:
                            (_type, _code) = splits[1].split("/")
                            if not check_icmpv6_type_code(_type, _code):
                                raise FirewallError(
                                    errors.INVALID_ENTRY,
                                    "invalid icmpv6 type '%s' in '%s'"
                                    % (splits[1], entry),
                                )
                    elif splits[0] not in [
                        "tcp",
                        "sctp",
                        "udp",
                        "udplite",
                    ] and not checkProtocol(splits[0]):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid protocol '%s' in '%s'" % (splits[0], entry),
                        )
                    elif not check_port(splits[1]):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid port '%s'in '%s'" % (splits[1], entry),
                        )
                else:
                    if not check_port(item):
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid port '%s' in '%s'" % (item, entry),
                        )
            elif flag == "mark":
                if item.startswith("0x"):
                    try:
                        int_val = int(item, 16)
                    except ValueError:
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid mark '%s' in '%s'" % (item, entry),
                        )
                else:
                    try:
                        int_val = int(item)
                    except ValueError:
                        raise FirewallError(
                            errors.INVALID_ENTRY,
                            "invalid mark '%s' in '%s'" % (item, entry),
                        )
                if int_val < 0 or int_val > 4294967295:
                    raise FirewallError(
                        errors.INVALID_ENTRY,
                        "invalid mark '%s' in '%s'" % (item, entry),
                    )
            elif flag == "iface":
                if not checkInterface(item) or len(item) > 15:
                    raise FirewallError(
                        errors.INVALID_ENTRY,
                        "invalid interface '%s' in '%s'" % (item, entry),
                    )
            else:
                raise FirewallError(
                    errors.INVALID_IPSET, "ipset type '%s' not usable" % ipset_type
                )

    def _check_config(self, config, item, all_config, all_io_objects):
        if item == "type":
            if config not in IPSET_TYPES:
                raise FirewallError(
                    errors.INVALID_TYPE, "'%s' is not valid ipset type" % config
                )
        if item == "options":
            for key in config.keys():
                if key not in IPSET_CREATE_OPTIONS:
                    raise FirewallError(
                        errors.INVALID_IPSET, "ipset invalid option '%s'" % key
                    )
                if key in ["timeout", "hashsize", "maxelem"]:
                    try:
                        int_value = int(config[key])
                    except ValueError:
                        raise FirewallError(
                            errors.INVALID_VALUE,
                            "Option '%s': Value '%s' is not an integer"
                            % (key, config[key]),
                        )
                    if int_value < 0:
                        raise FirewallError(
                            errors.INVALID_VALUE,
                            "Option '%s': Value '%s' is negative" % (key, config[key]),
                        )
                    if key == "maxelem" and len(self.entries) > int_value:
                        raise FirewallError(
                            errors.INVALID_IPSET,
                            "the number of ipset entries exceeds the maximum set size of %d"
                            % int_value,
                        )
                elif key == "family" and config[key] not in ["inet", "inet6"]:
                    raise FirewallError(errors.INVALID_FAMILY, config[key])

    def import_config(self, config, all_io_objects):
        if "timeout" in config[4] and config[4]["timeout"] != "0":
            if len(config[5]) != 0:
                raise FirewallError(errors.IPSET_WITH_TIMEOUT)
        for entry in config[5]:
            IPSet.check_entry(entry, config[4], config[3])
        super(IPSet, self).import_config(config, all_io_objects)


# PARSER


class ipset_ContentHandler(IO_Object_ContentHandler):
    def startElement(self, name, attrs):
        IO_Object_ContentHandler.startElement(self, name, attrs)
        self.item.parser_check_element_attrs(name, attrs)
        if name == "ipset":
            if "type" in attrs:
                if attrs["type"] not in IPSET_TYPES:
                    raise FirewallError(errors.INVALID_TYPE, "%s" % attrs["type"])
                self.item.type = attrs["type"]
            if "version" in attrs:
                self.item.version = attrs["version"]
        elif name == "short":
            pass
        elif name == "description":
            pass
        elif name == "option":
            value = ""
            if "value" in attrs:
                value = attrs["value"]

            if attrs["name"] not in ["family", "timeout", "hashsize", "maxelem"]:
                raise FirewallError(
                    errors.INVALID_OPTION, "Unknown option '%s'" % attrs["name"]
                )
            if self.item.type == "hash:mac" and attrs["name"] in ["family"]:
                raise FirewallError(
                    errors.INVALID_OPTION,
                    "Unsupported option '%s' for type '%s'"
                    % (attrs["name"], self.item.type),
                )
            if (
                attrs["name"] in ["family", "timeout", "hashsize", "maxelem"]
                and not value
            ):
                raise FirewallError(
                    errors.INVALID_OPTION,
                    "Missing mandatory value of option '%s'" % attrs["name"],
                )
            if attrs["name"] in ["timeout", "hashsize", "maxelem"]:
                try:
                    int_value = int(value)
                except ValueError:
                    raise FirewallError(
                        errors.INVALID_VALUE,
                        "Option '%s': Value '%s' is not an integer"
                        % (attrs["name"], value),
                    )
                if int_value < 0:
                    raise FirewallError(
                        errors.INVALID_VALUE,
                        "Option '%s': Value '%s' is negative" % (attrs["name"], value),
                    )
            if attrs["name"] == "family" and value not in ["inet", "inet6"]:
                raise FirewallError(errors.INVALID_FAMILY, value)
            if attrs["name"] not in self.item.options:
                self.item.options[attrs["name"]] = value
            else:
                log.warning("Option %s already set, ignoring.", attrs["name"])
        # nothing to do for entry and entries here

    def endElement(self, name):
        IO_Object_ContentHandler.endElement(self, name)
        if name == "entry":
            self.item.entries.append(self._element)


def ipset_reader(filename, path):
    ipset = IPSet()
    if not filename.endswith(".xml"):
        raise FirewallError(
            errors.INVALID_NAME, "'%s' is missing .xml suffix" % filename
        )
    ipset.name = filename[:-4]
    ipset.check_name(ipset.name)
    ipset.filename = filename
    ipset.path = path
    ipset.builtin = False if path.startswith(config.ETC_FIREWALLD) else True
    ipset.default = ipset.builtin
    handler = ipset_ContentHandler(ipset)
    parser = sax.make_parser()
    parser.setContentHandler(handler)
    name = "%s/%s" % (path, filename)
    with open(name, "rb") as f:
        source = sax.InputSource(None)
        source.setByteStream(f)
        try:
            parser.parse(source)
        except sax.SAXParseException as msg:
            raise FirewallError(
                errors.INVALID_IPSET, "not a valid ipset file: %s" % msg.getException()
            )
    del handler
    del parser
    if (
        "timeout" in ipset.options
        and ipset.options["timeout"] != "0"
        and len(ipset.entries) > 0
    ):
        # no entries visible for ipsets with timeout
        log.warning(
            "ipset '%s': timeout option is set, entries are ignored", ipset.name
        )
        del ipset.entries[:]
    i = 0
    entries_set = set()
    while i < len(ipset.entries):
        if ipset.entries[i] in entries_set:
            log.warning("Entry %s already set, ignoring.", ipset.entries[i])
            ipset.entries.pop(i)
        else:
            try:
                ipset.check_entry(ipset.entries[i], ipset.options, ipset.type)
            except FirewallError as e:
                log.warning("%s, ignoring.", e)
                ipset.entries.pop(i)
            else:
                entries_set.add(ipset.entries[i])
                i += 1
    del entries_set

    return ipset


def ipset_writer(ipset, path=None):
    _path = path if path else ipset.path

    if ipset.filename:
        name = "%s/%s" % (_path, ipset.filename)
    else:
        name = "%s/%s.xml" % (_path, ipset.name)

    if os.path.exists(name):
        try:
            shutil.copy2(name, "%s.old" % name)
        except Exception as msg:
            log.error("Backup of file '%s' failed: %s", name, msg)

    dirpath = os.path.dirname(name)
    if dirpath.startswith(config.ETC_FIREWALLD) and not os.path.exists(dirpath):
        if not os.path.exists(config.ETC_FIREWALLD):
            os.mkdir(config.ETC_FIREWALLD, 0o750)
        os.mkdir(dirpath, 0o750)

    f = io.open(name, mode="wt", encoding="UTF-8")
    handler = IO_Object_XMLGenerator(f)
    handler.startDocument()

    # start ipset element
    attrs = {"type": ipset.type}
    if ipset.version and ipset.version != "":
        attrs["version"] = ipset.version
    handler.startElement("ipset", attrs)
    handler.ignorableWhitespace("\n")

    # short
    if ipset.short and ipset.short != "":
        handler.ignorableWhitespace("  ")
        handler.startElement("short", {})
        handler.characters(ipset.short)
        handler.endElement("short")
        handler.ignorableWhitespace("\n")

    # description
    if ipset.description and ipset.description != "":
        handler.ignorableWhitespace("  ")
        handler.startElement("description", {})
        handler.characters(ipset.description)
        handler.endElement("description")
        handler.ignorableWhitespace("\n")

    # options
    for key, value in ipset.options.items():
        handler.ignorableWhitespace("  ")
        if value != "":
            handler.simpleElement("option", {"name": key, "value": value})
        else:
            handler.simpleElement("option", {"name": key})
        handler.ignorableWhitespace("\n")

    # entries
    for entry in ipset.entries:
        handler.ignorableWhitespace("  ")
        handler.startElement("entry", {})
        handler.characters(entry)
        handler.endElement("entry")
        handler.ignorableWhitespace("\n")

    # end ipset element
    handler.endElement("ipset")
    handler.ignorableWhitespace("\n")
    handler.endDocument()
    f.close()
    del handler