/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * (c) ZeroTier, Inc.
 * https://www.zerotier.com/
 */

"use strict";

// Names for bits in characteristics -- 0==LSB, 63==MSB
const CHARACTERISTIC_BITS = {
  inbound: 63,
  multicast: 62,
  broadcast: 61,
  ipauth: 60,
  macauth: 59,
  tcp_fin: 0,
  tcp_syn: 1,
  tcp_rst: 2,
  tcp_psh: 3,
  tcp_ack: 4,
  tcp_urg: 5,
  tcp_ece: 6,
  tcp_cwr: 7,
  tcp_ns: 8,
  tcp_rs2: 9,
  tcp_rs1: 10,
  tcp_rs0: 11,
};

// Shorthand names for common ethernet types
const ETHERTYPES = {
  ipv4: 0x0800,
  arp: 0x0806,
  wol: 0x0842,
  rarp: 0x8035,
  ipv6: 0x86dd,
  atalk: 0x809b,
  aarp: 0x80f3,
  ipx_a: 0x8137,
  ipx_b: 0x8138,
};

// Shorthand names for common IP protocols
const IP_PROTOCOLS = {
  icmp: 0x01,
  icmp4: 0x01,
  icmpv4: 0x01,
  igmp: 0x02,
  ipip: 0x04,
  tcp: 0x06,
  egp: 0x08,
  igp: 0x09,
  udp: 0x11,
  rdp: 0x1b,
  esp: 0x32,
  ah: 0x33,
  icmp6: 0x3a,
  icmpv6: 0x3a,
  l2tp: 0x73,
  sctp: 0x84,
  udplite: 0x88,
};

// Keywords that open new blocks that must be terminated by a semicolon
const OPEN_BLOCK_KEYWORDS = {
  macro: true,
  tag: true,
  cap: true,
  drop: true,
  accept: true,
  tee: true,
  watch: true,
  redirect: true,
  break: true,
  priority: true,
};

// Reserved words that can't be used as tag, capability, or rule set names
const RESERVED_WORDS = {
  macro: true,
  tag: true,
  cap: true,
  default: true,

  drop: true,
  accept: true,
  tee: true,
  watch: true,
  redirect: true,
  break: true,
  priority: true,

  ztsrc: true,
  ztdest: true,
  vlan: true,
  vlanpcp: true,
  vlandei: true,
  ethertype: true,
  macsrc: true,
  macdest: true,
  ipsrc: true,
  ipdest: true,
  iptos: true,
  ipprotocol: true,
  icmp: true,
  sport: true,
  dport: true,
  chr: true,
  framesize: true,
  random: true,
  tand: true,
  tor: true,
  txor: true,
  tdiff: true,
  teq: true,
  tseq: true,
  treq: true,

  type: true,
  enum: true,
  class: true,
  define: true,
  import: true,
  include: true,
  log: true,
  not: true,
  xor: true,
  or: true,
  and: true,
  set: true,
  var: true,
  let: true,
};

const KEYWORD_TO_API_MAP = {
  drop: "ACTION_DROP",
  accept: "ACTION_ACCEPT",
  tee: "ACTION_TEE",
  watch: "ACTION_WATCH",
  redirect: "ACTION_REDIRECT",
  break: "ACTION_BREAK",
  priority: "ACTION_PRIORITY",

  ztsrc: "MATCH_SOURCE_ZEROTIER_ADDRESS",
  ztdest: "MATCH_DEST_ZEROTIER_ADDRESS",
  vlan: "MATCH_VLAN_ID",
  vlanpcp: "MATCH_VLAN_PCP",
  vlandei: "MATCH_VLAN_DEI",
  ethertype: "MATCH_ETHERTYPE",
  macsrc: "MATCH_MAC_SOURCE",
  macdest: "MATCH_MAC_DEST",
  //'ipsrc': '', // special handling since we programmatically differentiate between V4 and V6
  //'ipdest': '', // special handling
  iptos: "MATCH_IP_TOS",
  ipprotocol: "MATCH_IP_PROTOCOL",
  icmp: "MATCH_ICMP",
  sport: "MATCH_IP_SOURCE_PORT_RANGE",
  dport: "MATCH_IP_DEST_PORT_RANGE",
  chr: "MATCH_CHARACTERISTICS",
  framesize: "MATCH_FRAME_SIZE_RANGE",
  random: "MATCH_RANDOM",
  tand: "MATCH_TAGS_BITWISE_AND",
  tor: "MATCH_TAGS_BITWISE_OR",
  txor: "MATCH_TAGS_BITWISE_XOR",
  tdiff: "MATCH_TAGS_DIFFERENCE",
  teq: "MATCH_TAGS_EQUAL",
  tseq: "MATCH_TAG_SENDER",
  treq: "MATCH_TAG_RECEIVER",
};

// Number of args for each match
const MATCH_ARG_COUNTS = {
  ztsrc: 1,
  ztdest: 1,
  vlan: 1,
  vlanpcp: 1,
  vlandei: 1,
  ethertype: 1,
  macsrc: 1,
  macdest: 1,
  ipsrc: 1,
  ipdest: 1,
  iptos: 2,
  ipprotocol: 1,
  icmp: 2,
  sport: 1,
  dport: 1,
  chr: 1,
  framesize: 1,
  random: 1,
  tand: 2,
  tor: 2,
  txor: 2,
  tdiff: 2,
  teq: 2,
  tseq: 2,
  treq: 2,
};

// Regex of all alphanumeric characters in Unicode
const INTL_ALPHANUM_REGEX = new RegExp(
  "[0-9A-Za-z\xAA\xB5\xBA\xC0-\xD6\xD8-\xF6\xF8-\u02C1\u02C6-\u02D1\u02E0-\u02E4\u02EC\u02EE\u0370-\u0374\u0376\u0377\u037A-\u037D\u0386\u0388-\u038A\u038C\u038E-\u03A1\u03A3-\u03F5\u03F7-\u0481\u048A-\u0527\u0531-\u0556\u0559\u0561-\u0587\u05D0-\u05EA\u05F0-\u05F2\u0620-\u064A\u066E\u066F\u0671-\u06D3\u06D5\u06E5\u06E6\u06EE\u06EF\u06FA-\u06FC\u06FF\u0710\u0712-\u072F\u074D-\u07A5\u07B1\u07CA-\u07EA\u07F4\u07F5\u07FA\u0800-\u0815\u081A\u0824\u0828\u0840-\u0858\u08A0\u08A2-\u08AC\u0904-\u0939\u093D\u0950\u0958-\u0961\u0971-\u0977\u0979-\u097F\u0985-\u098C\u098F\u0990\u0993-\u09A8\u09AA-\u09B0\u09B2\u09B6-\u09B9\u09BD\u09CE\u09DC\u09DD\u09DF-\u09E1\u09F0\u09F1\u0A05-\u0A0A\u0A0F\u0A10\u0A13-\u0A28\u0A2A-\u0A30\u0A32\u0A33\u0A35\u0A36\u0A38\u0A39\u0A59-\u0A5C\u0A5E\u0A72-\u0A74\u0A85-\u0A8D\u0A8F-\u0A91\u0A93-\u0AA8\u0AAA-\u0AB0\u0AB2\u0AB3\u0AB5-\u0AB9\u0ABD\u0AD0\u0AE0\u0AE1\u0B05-\u0B0C\u0B0F\u0B10\u0B13-\u0B28\u0B2A-\u0B30\u0B32\u0B33\u0B35-\u0B39\u0B3D\u0B5C\u0B5D\u0B5F-\u0B61\u0B71\u0B83\u0B85-\u0B8A\u0B8E-\u0B90\u0B92-\u0B95\u0B99\u0B9A\u0B9C\u0B9E\u0B9F\u0BA3\u0BA4\u0BA8-\u0BAA\u0BAE-\u0BB9\u0BD0\u0C05-\u0C0C\u0C0E-\u0C10\u0C12-\u0C28\u0C2A-\u0C33\u0C35-\u0C39\u0C3D\u0C58\u0C59\u0C60\u0C61\u0C85-\u0C8C\u0C8E-\u0C90\u0C92-\u0CA8\u0CAA-\u0CB3\u0CB5-\u0CB9\u0CBD\u0CDE\u0CE0\u0CE1\u0CF1\u0CF2\u0D05-\u0D0C\u0D0E-\u0D10\u0D12-\u0D3A\u0D3D\u0D4E\u0D60\u0D61\u0D7A-\u0D7F\u0D85-\u0D96\u0D9A-\u0DB1\u0DB3-\u0DBB\u0DBD\u0DC0-\u0DC6\u0E01-\u0E30\u0E32\u0E33\u0E40-\u0E46\u0E81\u0E82\u0E84\u0E87\u0E88\u0E8A\u0E8D\u0E94-\u0E97\u0E99-\u0E9F\u0EA1-\u0EA3\u0EA5\u0EA7\u0EAA\u0EAB\u0EAD-\u0EB0\u0EB2\u0EB3\u0EBD\u0EC0-\u0EC4\u0EC6\u0EDC-\u0EDF\u0F00\u0F40-\u0F47\u0F49-\u0F6C\u0F88-\u0F8C\u1000-\u102A\u103F\u1050-\u1055\u105A-\u105D\u1061\u1065\u1066\u106E-\u1070\u1075-\u1081\u108E\u10A0-\u10C5\u10C7\u10CD\u10D0-\u10FA\u10FC-\u1248\u124A-\u124D\u1250-\u1256\u1258\u125A-\u125D\u1260-\u1288\u128A-\u128D\u1290-\u12B0\u12B2-\u12B5\u12B8-\u12BE\u12C0\u12C2-\u12C5\u12C8-\u12D6\u12D8-\u1310\u1312-\u1315\u1318-\u135A\u1380-\u138F\u13A0-\u13F4\u1401-\u166C\u166F-\u167F\u1681-\u169A\u16A0-\u16EA\u1700-\u170C\u170E-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176C\u176E-\u1770\u1780-\u17B3\u17D7\u17DC\u1820-\u1877\u1880-\u18A8\u18AA\u18B0-\u18F5\u1900-\u191C\u1950-\u196D\u1970-\u1974\u1980-\u19AB\u19C1-\u19C7\u1A00-\u1A16\u1A20-\u1A54\u1AA7\u1B05-\u1B33\u1B45-\u1B4B\u1B83-\u1BA0\u1BAE\u1BAF\u1BBA-\u1BE5\u1C00-\u1C23\u1C4D-\u1C4F\u1C5A-\u1C7D\u1CE9-\u1CEC\u1CEE-\u1CF1\u1CF5\u1CF6\u1D00-\u1DBF\u1E00-\u1F15\u1F18-\u1F1D\u1F20-\u1F45\u1F48-\u1F4D\u1F50-\u1F57\u1F59\u1F5B\u1F5D\u1F5F-\u1F7D\u1F80-\u1FB4\u1FB6-\u1FBC\u1FBE\u1FC2-\u1FC4\u1FC6-\u1FCC\u1FD0-\u1FD3\u1FD6-\u1FDB\u1FE0-\u1FEC\u1FF2-\u1FF4\u1FF6-\u1FFC\u2071\u207F\u2090-\u209C\u2102\u2107\u210A-\u2113\u2115\u2119-\u211D\u2124\u2126\u2128\u212A-\u212D\u212F-\u2139\u213C-\u213F\u2145-\u2149\u214E\u2183\u2184\u2C00-\u2C2E\u2C30-\u2C5E\u2C60-\u2CE4\u2CEB-\u2CEE\u2CF2\u2CF3\u2D00-\u2D25\u2D27\u2D2D\u2D30-\u2D67\u2D6F\u2D80-\u2D96\u2DA0-\u2DA6\u2DA8-\u2DAE\u2DB0-\u2DB6\u2DB8-\u2DBE\u2DC0-\u2DC6\u2DC8-\u2DCE\u2DD0-\u2DD6\u2DD8-\u2DDE\u2E2F\u3005\u3006\u3031-\u3035\u303B\u303C\u3041-\u3096\u309D-\u309F\u30A1-\u30FA\u30FC-\u30FF\u3105-\u312D\u3131-\u318E\u31A0-\u31BA\u31F0-\u31FF\u3400-\u4DB5\u4E00-\u9FCC\uA000-\uA48C\uA4D0-\uA4FD\uA500-\uA60C\uA610-\uA61F\uA62A\uA62B\uA640-\uA66E\uA67F-\uA697\uA6A0-\uA6E5\uA717-\uA71F\uA722-\uA788\uA78B-\uA78E\uA790-\uA793\uA7A0-\uA7AA\uA7F8-\uA801\uA803-\uA805\uA807-\uA80A\uA80C-\uA822\uA840-\uA873\uA882-\uA8B3\uA8F2-\uA8F7\uA8FB\uA90A-\uA925\uA930-\uA946\uA960-\uA97C\uA984-\uA9B2\uA9CF\uAA00-\uAA28\uAA40-\uAA42\uAA44-\uAA4B\uAA60-\uAA76\uAA7A\uAA80-\uAAAF\uAAB1\uAAB5\uAAB6\uAAB9-\uAABD\uAAC0\uAAC2\uAADB-\uAADD\uAAE0-\uAAEA\uAAF2-\uAAF4\uAB01-\uAB06\uAB09-\uAB0E\uAB11-\uAB16\uAB20-\uAB26\uAB28-\uAB2E\uABC0-\uABE2\uAC00-\uD7A3\uD7B0-\uD7C6\uD7CB-\uD7FB\uF900-\uFA6D\uFA70-\uFAD9\uFB00-\uFB06\uFB13-\uFB17\uFB1D\uFB1F-\uFB28\uFB2A-\uFB36\uFB38-\uFB3C\uFB3E\uFB40\uFB41\uFB43\uFB44\uFB46-\uFBB1\uFBD3-\uFD3D\uFD50-\uFD8F\uFD92-\uFDC7\uFDF0-\uFDFB\uFE70-\uFE74\uFE76-\uFEFC\uFF21-\uFF3A\uFF41-\uFF5A\uFF66-\uFFBE\uFFC2-\uFFC7\uFFCA-\uFFCF\uFFD2-\uFFD7\uFFDA-\uFFDC]",
);

// Checks whether something is a valid capability, tag, or macro name
function _isValidName(n) {
  if (typeof n !== "string" || n.length === 0) return false;
  if ("0123456789".indexOf(n.charAt(0)) >= 0) return false;
  for (let i = 0; i < n.length; ++i) {
    let c = n.charAt(i);
    if (c !== "_" && !INTL_ALPHANUM_REGEX.test(c)) return false;
  }
  return true;
}

// Regexes for checking the basic syntactic validity of IP addresses
const IPV6_REGEX = new RegExp(
  "(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|([0-9a-fA-F]{1,4}:){1,6}:[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,5}(:[0-9a-fA-F]{1,4}){1,2}|([0-9a-fA-F]{1,4}:){1,4}(:[0-9a-fA-F]{1,4}){1,3}|([0-9a-fA-F]{1,4}:){1,3}(:[0-9a-fA-F]{1,4}){1,4}|([0-9a-fA-F]{1,4}:){1,2}(:[0-9a-fA-F]{1,4}){1,5}|[0-9a-fA-F]{1,4}:((:[0-9a-fA-F]{1,4}){1,6})|:((:[0-9a-fA-F]{1,4}){1,7}|:)|fe80:(:[0-9a-fA-F]{0,4}){0,4}%[0-9a-zA-Z]{1,}|::(ffff(:0{1,4}){0,1}:){0,1}((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])|([0-9a-fA-F]{1,4}:){1,4}:((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9]))",
);
const IPV4_REGEX = new RegExp(
  "((25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])\\.){3,3}(25[0-5]|(2[0-4]|1{0,1}[0-9]){0,1}[0-9])",
);

function _parseNum(n) {
  try {
    if (typeof n !== "string" || n.length === 0) return -1;
    n = n.toLowerCase();
    if (n.length > 2 && n.substr(0, 2) === "0x") n = parseInt(n.substr(2), 16);
    else n = parseInt(n, 10);
    return typeof n === "number" && n !== null && !isNaN(n) ? n : -1;
  } catch (e) {
    return -1;
  }
}

function _cleanMac(m) {
  m = m.toLowerCase();
  var m2 = "";
  let charcount = 0;
  for (let i = 0; i < m.length && m2.length < 17; ++i) {
    let c = m.charAt(i);
    if ("0123456789abcdef".indexOf(c) >= 0) {
      m2 += c;
      charcount++;
      if (m2.length > 0 && m2.length !== 17 && charcount >= 2) {
        m2 += ":";
        charcount = 0;
      }
    }
  }
  return m2;
}

function _cleanHex(m) {
  m = m.toLowerCase();
  var m2 = "";
  for (let i = 0; i < m.length; ++i) {
    let c = m.charAt(i);
    if ("0123456789abcdef".indexOf(c) >= 0) m2 += c;
  }
  return m2;
}

function _renderMatches(mtree, rules, macros, caps, tags, params) {
  let not = false;
  let or = false;
  for (let k = 0; k < mtree.length; ++k) {
    let match =
      typeof mtree[k][0] === "string" ? mtree[k][0].toLowerCase() : "";
    if (match.length === 0 || match === "and") {
      // AND is the default
      continue;
    } else if (match === "not") {
      not = true;
    } else if (match === "or") {
      or = true;
    } else {
      let args = [];
      let argCount = MATCH_ARG_COUNTS[match];
      if (!argCount)
        return [
          mtree[k][1],
          mtree[k][2],
          'Unrecognized match type "' + match + '".',
        ];
      for (let i = 0; i < argCount; ++i) {
        if (++k >= mtree.length)
          return [
            mtree[k - 1][1],
            mtree[k - 1][2],
            "Missing argument(s) to match.",
          ];
        let arg = mtree[k][0];
        if (
          typeof arg !== "string" ||
          arg in RESERVED_WORDS ||
          arg.length === 0
        )
          return [
            mtree[k - 1][1],
            mtree[k - 1][2],
            "Missing argument(s) to match (invalid argument or argument is reserved word).",
          ];
        if (arg.charAt(0) === "$") {
          let tmp = params[arg];
          if (typeof tmp === "undefined")
            return [mtree[k][1], mtree[k][2], "Undefined variable name."];
          args.push([tmp, mtree[k][1], mtree[k][2]]);
        } else {
          args.push(mtree[k]);
        }
      }

      switch (match) {
        case "ztsrc":
        case "ztdest":
          {
            let zt = _cleanHex(args[0][0]);
            if (zt.length !== 10)
              return [args[0][1], args[0][2], "Invalid ZeroTier address."];
            rules.push({
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
              zt: zt,
            });
          }
          break;

        case "vlan":
        case "vlanpcp":
        case "vlandei":
        case "ethertype":
        case "ipprotocol":
          {
            let num = null;
            switch (match) {
              case "ethertype":
                num = ETHERTYPES[args[0][0]];
                break;
              case "ipprotocol":
                num = IP_PROTOCOLS[args[0][0]];
                break;
            }
            if (typeof num !== "number") num = _parseNum(args[0][0]);
            if (
              typeof num !== "number" ||
              num < 0 ||
              num > 0xffffffff ||
              num === null
            )
              return [args[0][1], args[0][2], "Invalid numeric value."];
            let r = {
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
            };
            switch (match) {
              case "vlan":
                r["vlanId"] = num;
                break;
              case "vlanpcp":
                r["vlanPcp"] = num;
                break;
              case "vlandei":
                r["vlanDei"] = num;
                break;
              case "ethertype":
                r["etherType"] = num;
                break;
              case "ipprotocol":
                r["ipProtocol"] = num;
                break;
            }
            rules.push(r);
          }
          break;

        case "random":
          {
            let num = parseFloat(args[0][0]) || 0.0;
            if (num < 0.0) num = 0.0;
            if (num > 1.0) num = 1.0;
            rules.push({
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
              probability: Math.floor(4294967295 * num),
            });
          }
          break;

        case "macsrc":
        case "macdest":
          {
            let mac = _cleanMac(args[0][0]);
            if (mac.length !== 17)
              return [args[0][1], args[0][2], "Invalid MAC address."];
            rules.push({
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
              mac: mac,
            });
          }
          break;

        case "ipsrc":
        case "ipdest":
          {
            let ip = args[0][0];
            let slashIdx = ip.indexOf("/");
            if (slashIdx <= 0)
              return [
                args[0][1],
                args[0][2],
                "Missing /bits netmask length designation in IP.",
              ];
            let ipOnly = ip.substr(0, slashIdx);
            if (IPV6_REGEX.test(ipOnly)) {
              rules.push({
                type:
                  match === "ipsrc" ? "MATCH_IPV6_SOURCE" : "MATCH_IPV6_DEST",
                not: not,
                or: or,
                ip: ip,
              });
            } else if (IPV4_REGEX.test(ipOnly)) {
              rules.push({
                type:
                  match === "ipsrc" ? "MATCH_IPV4_SOURCE" : "MATCH_IPV4_DEST",
                not: not,
                or: or,
                ip: ip,
              });
            } else {
              return [
                args[0][1],
                args[0][2],
                "Invalid IP address (not valid IPv4 or IPv6).",
              ];
            }
          }
          break;

        case "icmp":
          {
            let icmpType = _parseNum(args[0][0]);
            if (icmpType < 0 || icmpType > 0xff)
              return [args[0][1], args[0][2], "Missing or invalid ICMP type."];
            let icmpCode = _parseNum(args[1][0]); // -1 okay, indicates don't match code
            if (icmpCode > 0xff)
              return [
                args[1][1],
                args[1][2],
                "Invalid ICMP code (use -1 for none).",
              ];
            rules.push({
              type: "MATCH_ICMP",
              not: not,
              or: or,
              icmpType: icmpType,
              icmpCode: icmpCode < 0 ? null : icmpCode,
            });
          }
          break;

        case "sport":
        case "dport":
        case "framesize":
          {
            let arg = args[0][0];
            let fn = null;
            let tn = null;
            if (arg.indexOf("-") > 0) {
              let asplit = arg.split("-");
              if (asplit.length !== 2) {
                return [args[0][1], args[0][2], "Invalid numeric range."];
              } else {
                fn = _parseNum(asplit[0]);
                tn = _parseNum(asplit[1]);
              }
            } else {
              fn = _parseNum(arg);
              tn = fn;
            }
            if (fn < 0 || fn > 0xffff || tn < 0 || tn > 0xffff || tn < fn)
              return [args[0][1], args[0][2], "Invalid numeric range."];
            rules.push({
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
              start: fn,
              end: tn,
            });
          }
          break;

        case "iptos":
          {
            let mask = _parseNum(args[0][0]);
            if (
              typeof mask !== "number" ||
              mask < 0 ||
              mask > 0xff ||
              mask === null
            )
              return [args[0][1], args[0][2], "Invalid mask."];
            let arg = args[1][0];
            let fn = null;
            let tn = null;
            if (arg.indexOf("-") > 0) {
              let asplit = arg.split("-");
              if (asplit.length !== 2) {
                return [args[1][1], args[1][2], "Invalid value range."];
              } else {
                fn = _parseNum(asplit[0]);
                tn = _parseNum(asplit[1]);
              }
            } else {
              fn = _parseNum(arg);
              tn = fn;
            }
            if (fn < 0 || fn > 0xff || tn < 0 || tn > 0xff || tn < fn)
              return [args[1][1], args[1][2], "Invalid value range."];
            rules.push({
              type: "MATCH_IP_TOS",
              not: not,
              or: or,
              mask: mask,
              start: fn,
              end: tn,
            });
          }
          break;

        case "chr":
          {
            let chrb = args[0][0].split(/[,]+/);
            let maskhi = 0;
            let masklo = 0;
            for (let i = 0; i < chrb.length; ++i) {
              if (chrb[i].length > 0) {
                let tmp = CHARACTERISTIC_BITS[chrb[i]];
                let bit = typeof tmp === "number" ? tmp : _parseNum(chrb[i]);
                if (bit < 0 || bit > 63)
                  return [
                    args[0][1],
                    args[0][2],
                    "Invalid bit index (range 0-63) or unrecognized name.",
                  ];
                if (bit >= 32) maskhi |= Math.abs(1 << (bit - 32));
                else masklo |= Math.abs(1 << bit);
              }
            }
            maskhi = Math.abs(maskhi).toString(16);
            while (maskhi.length < 8) maskhi = "0" + maskhi;
            masklo = Math.abs(masklo).toString(16);
            while (masklo.length < 8) masklo = "0" + masklo;
            rules.push({
              type: "MATCH_CHARACTERISTICS",
              not: not,
              or: or,
              mask: maskhi + masklo,
            });
          }
          break;

        case "tand":
        case "tor":
        case "txor":
        case "tdiff":
        case "teq":
        case "tseq":
        case "treq":
          {
            let tag = tags[args[0][0]];
            let tagId = -1;
            let tagValue = -1;
            if (tag) {
              tagId = tag.id;
              tagValue = args[1][0];
              if (tagValue in tag.flags) tagValue = tag.flags[tagValue];
              else if (tagValue in tag.enums) tagValue = tag.enums[tagValue];
              else tagValue = _parseNum(tagValue);
            } else {
              tagId = _parseNum(args[0][0]);
              tagValue = _parseNum(args[1][0]);
            }
            if (tagId < 0 || tagId > 0xffffffff)
              return [
                args[0][1],
                args[0][2],
                "Undefined tag name and invalid tag value.",
              ];
            if (tagValue < 0 || tagValue > 0xffffffff)
              return [
                args[1][1],
                args[1][2],
                "Invalid tag value or unrecognized flag/enum name.",
              ];
            rules.push({
              type: KEYWORD_TO_API_MAP[match],
              not: not,
              or: or,
              id: tagId,
              value: tagValue,
            });
          }
          break;
      }

      not = false;
      or = false;
    }
  }
  return null;
}

function _renderActions(rtree, rules, macros, caps, tags, params) {
  for (let k = 0; k < rtree.length; ++k) {
    let action =
      typeof rtree[k][0] === "string" ? rtree[k][0].toLowerCase() : "";
    if (action.length === 0) {
      continue;
    } else if (action === "include") {
      if (k + 1 >= rtree.length)
        return [
          rtree[k][1],
          rtree[k][2],
          "Include directive is missing a macro name.",
        ];
      let macroName = rtree[k + 1][0];
      ++k;

      let macroParamArray = [];
      let parenIdx = macroName.indexOf("(");
      if (parenIdx > 0) {
        let pns = macroName.substr(parenIdx + 1).split(/[,)]+/);
        for (let k = 0; k < pns.length; ++k) {
          if (pns[k].length > 0) macroParamArray.push(pns[k]);
        }
        macroName = macroName.substr(0, parenIdx);
      }

      let macro = macros[macroName];
      if (!macro) return [rtree[k][1], rtree[k][2], "Macro name not found."];
      let macroParams = {};
      for (let param in macro.params) {
        let pidx = macro.params[param];
        if (pidx >= macroParamArray.length)
          return [
            rtree[k][1],
            rtree[k][2],
            "Missing one or more required macro parameter.",
          ];
        macroParams[param] = macroParamArray[pidx];
      }

      let err = _renderActions(
        macro.rules,
        rules,
        macros,
        caps,
        tags,
        macroParams,
      );
      if (err !== null) return err;
    } else if (action === "drop" || action === "accept" || action === "break") {
      // actions without arguments
      if (k + 1 < rtree.length && Array.isArray(rtree[k + 1][0])) {
        let mtree = rtree[k + 1];
        ++k;
        let err = _renderMatches(mtree, rules, macros, caps, tags, params);
        if (err !== null) return err;
      }
      rules.push({
        type: KEYWORD_TO_API_MAP[action],
      });
    } else if (action === "tee" || action === "watch") {
      // actions with arguments (ZeroTier address)
      if (
        k + 1 < rtree.length &&
        Array.isArray(rtree[k + 1][0]) &&
        rtree[k + 1][0].length >= 2
      ) {
        let mtree = rtree[k + 1];
        ++k;
        let maxLength = _parseNum(mtree[0][0]);
        if (maxLength < -1 || maxLength > 0xffff)
          return [
            mtree[0][1],
            mtree[1][2],
            "Tee/watch max packet length to forward invalid or out of range.",
          ];
        let target = mtree[1][0];
        if (typeof target !== "string" || target.length !== 10)
          return [
            mtree[1][1],
            mtree[1][2],
            "Missing or invalid ZeroTier address target for tee/watch.",
          ];
        let err = _renderMatches(
          mtree.slice(2),
          rules,
          macros,
          caps,
          tags,
          params,
        );
        if (err !== null) return err;
        rules.push({
          type: KEYWORD_TO_API_MAP[action],
          address: target,
          length: maxLength,
        });
      } else {
        return [
          rtree[k][1],
          rtree[k][2],
          "The tee and watch actions require two paremters (max length or 0 for all, target).",
        ];
      }
    } else if (action === "redirect") {
      if (
        k + 1 < rtree.length &&
        Array.isArray(rtree[k + 1][0]) &&
        rtree[k + 1][0].length >= 1
      ) {
        let mtree = rtree[k + 1];
        ++k;
        let target = mtree[0][0];
        if (typeof target !== "string" || target.length !== 10)
          return [
            mtree[0][1],
            mtree[0][2],
            "Missing or invalid ZeroTier address target for redirect.",
          ];
        let err = _renderMatches(
          mtree.slice(1),
          rules,
          macros,
          caps,
          tags,
          params,
        );
        if (err !== null) return err;
        rules.push({
          type: KEYWORD_TO_API_MAP[action],
          address: target,
        });
      } else {
        return [
          rtree[k][1],
          rtree[k][2],
          "The redirect action requires a target parameter.",
        ];
      }
    } else {
      return [
        rtree[k][1],
        rtree[k][2],
        "Unrecognized action or directive in rule set.",
      ];
    }
  }

  return null;
}

function compile(src, rules, caps, tags) {
  try {
    if (typeof src !== "string")
      return [0, 0, '"src" parameter must be a string.'];

    // Pass 1: parse source into a tree of arrays of elements. Each element is a 3-item
    // tuple consisting of string, line number, and character index in line to enable
    // informative error messages to be returned.

    var blockStack = [[]];
    var curr = ["", -1, -1];
    var skipRestOfLine = false;
    for (
      let idx = 0, lineNo = 1, lineIdx = 0;
      idx < src.length;
      ++idx, ++lineIdx
    ) {
      let ch = src.charAt(idx);
      if (skipRestOfLine) {
        if (ch === "\r" || ch === "\n") {
          skipRestOfLine = false;
          ++lineNo;
          lineIdx = 0;
        }
      } else {
        switch (ch) {
          case "\n":
            ++lineNo;
            lineIdx = 0;
          case "\r":
          case "\t":
          case " ":
            if (curr[0].length > 0) {
              let endOfBlock = false;
              if (curr[0].charAt(curr[0].length - 1) === ";") {
                endOfBlock = true;
                curr[0] = curr[0].substr(0, curr[0].length - 1);
              }

              if (curr[0].length > 0) {
                blockStack[blockStack.length - 1].push(curr);
              }
              if (
                endOfBlock &&
                blockStack.length > 1 &&
                blockStack[blockStack.length - 1].length > 0
              ) {
                blockStack[blockStack.length - 2].push(
                  blockStack[blockStack.length - 1],
                );
                blockStack.pop();
              } else if (curr[0] in OPEN_BLOCK_KEYWORDS) {
                blockStack.push([]);
              }

              curr = ["", -1, -1];
            }
            break;
          default:
            if (curr[0].length === 0) {
              if (ch === "#") {
                skipRestOfLine = true;
                continue;
              } else {
                curr[1] = lineNo;
                curr[2] = lineIdx;
              }
            }
            curr[0] += ch;
            break;
        }
      }
    }

    if (curr[0].length > 0) {
      if (curr[0].charAt(curr[0].length - 1) === ";")
        curr[0] = curr[0].substr(0, curr[0].length - 1);
      if (curr[0].length > 0) blockStack[blockStack.length - 1].push(curr);
    }
    while (
      blockStack.length > 1 &&
      blockStack[blockStack.length - 1].length > 0
    ) {
      blockStack[blockStack.length - 2].push(blockStack[blockStack.length - 1]);
      blockStack.pop();
    }
    var parsed = blockStack[0];

    // Pass 2: parse tree into capabilities, tags, rule sets, and document-level rules.

    let baseRuleTree = [];
    let macros = {};
    for (let i = 0; i < parsed.length; ++i) {
      let keyword =
        typeof parsed[i][0] === "string" ? parsed[i][0].toLowerCase() : null;
      if (keyword === "macro") {
        // Define macros

        if (
          i + 1 >= parsed.length ||
          !Array.isArray(parsed[i + 1]) ||
          parsed[i + 1].length < 1 ||
          !Array.isArray(parsed[i + 1][0])
        )
          return [
            parsed[i][1],
            parsed[i][2],
            "Macro definition is missing name.",
          ];
        let macro = parsed[++i];
        let macroName = macro[0][0].toLowerCase();

        let params = {};
        let parenIdx = macroName.indexOf("(");
        if (parenIdx > 0) {
          let pns = macroName.substr(parenIdx + 1).split(/[,)]+/);
          for (let k = 0; k < pns.length; ++k) {
            if (pns[k].length > 0) params[pns[k]] = k;
          }
          macroName = macroName.substr(0, parenIdx);
        }

        if (!_isValidName(macroName))
          return [macro[0][1], macro[0][2], "Invalid macro name."];
        if (macroName in RESERVED_WORDS)
          return [macro[0][1], macro[0][2], "Macro name is a reserved word."];

        if (macroName in macros)
          return [
            macro[0][1],
            macro[0][2],
            "Multiple definition of macro name.",
          ];

        macros[macroName] = {
          params: params,
          rules: macro.slice(1),
        };
      } else if (keyword === "tag") {
        // Define tags

        if (
          i + 1 >= parsed.length ||
          !Array.isArray(parsed[i + 1]) ||
          parsed[i + 1].length < 1 ||
          !Array.isArray(parsed[i + 1][0])
        )
          return [
            parsed[i][1],
            parsed[i][2],
            "Tag definition is missing name.",
          ];
        let tag = parsed[++i];
        let tagName = tag[0][0].toLowerCase();

        if (!_isValidName(tagName))
          return [tag[0][1], tag[0][2], "Invalid tag name."];
        if (tagName in RESERVED_WORDS)
          return [tag[0][1], tag[0][2], "Tag name is a reserved word."];

        if (tagName in tags)
          return [tag[0][1], tag[0][2], "Multiple definition of tag name."];

        let flags = {};
        let enums = {};
        let id = -1;
        let dfl = null;
        for (let k = 1; k < tag.length; ++k) {
          let tkeyword = tag[k][0].toLowerCase();
          if (tkeyword === "id") {
            if (id >= 0)
              return [tag[k][1], tag[k][2], "Duplicate tag id definition."];
            if (k + 1 >= tag.length)
              return [tag[k][1], tag[k][2], "Missing numeric value for ID."];
            id = _parseNum(tag[++k][0]);
            if (id < 0 || id > 0xffffffff)
              return [tag[k][1], tag[k][2], "Invalid or out of range tag ID."];
          } else if (tkeyword === "default") {
            if (dfl !== null)
              return [tag[k][1], tag[k][2], "Duplicate tag default directive."];
            if (k + 1 >= tag.length)
              return [tag[k][1], tag[k][2], "Missing value for default."];
            dfl = tag[++k][0];
          } else if (tkeyword === "flag") {
            if (k + 2 >= tag.length)
              return [
                tag[k][1],
                tag[k][2],
                "Missing tag flag name or bit index.",
              ];
            ++k;
            let bits = tag[k][0].split(/[,]+/);
            let mask = 0;
            for (let j = 0; j < bits.length; ++j) {
              let b = bits[j].toLowerCase();
              if (b in flags) {
                mask |= flags[b];
              } else {
                b = _parseNum(b);
                if (b < 0 || b > 31)
                  return [
                    tag[k][1],
                    tag[k][2],
                    "Bit index invalid, out of range, or references an undefined flag name.",
                  ];
                mask |= 1 << b;
              }
            }
            let flagName = tag[++k][0].toLowerCase();
            if (!_isValidName(flagName))
              return [tag[k][1], tag[k][2], "Invalid or reserved flag name."];
            if (flagName in flags)
              return [
                tag[k][1],
                tag[k][2],
                "Duplicate flag name in tag definition.",
              ];
            flags[flagName] = mask;
          } else if (tkeyword === "enum") {
            if (k + 2 >= tag.length)
              return [tag[k][1], tag[k][2], "Missing tag enum name or value."];
            ++k;
            let value = _parseNum(tag[k][0]);
            if (value < 0 || value > 0xffffffff)
              return [
                tag[k][1],
                tag[k][2],
                "Tag enum value invalid or out of range.",
              ];
            let enumName = tag[++k][0].toLowerCase();
            if (!_isValidName(enumName))
              return [
                tag[k][1],
                tag[k][2],
                "Invalid or reserved tag enum name.",
              ];
            if (enumName in enums)
              return [
                tag[k][1],
                tag[k][2],
                "Duplicate enum name in tag definition.",
              ];
            enums[enumName] = value;
          } else {
            return [
              tag[k][1],
              tag[k][2],
              "Unrecognized keyword in tag definition.",
            ];
          }
        }
        if (id < 0)
          return [
            tag[0][1],
            tag[0][2],
            "Tag definition is missing a numeric ID.",
          ];

        if (typeof dfl === "string") {
          let dfl2 = enums[dfl];
          if (typeof dfl2 === "number") {
            dfl = dfl2;
          } else {
            dfl2 = flags[dfl];
            if (typeof dfl2 === "number") {
              dfl = dfl2;
            } else {
              dfl = Math.abs(parseInt(dfl) || 0) & 0xffffffff;
            }
          }
        } else if (typeof dfl === "number") {
          dfl = Math.abs(dfl) & 0xffffffff;
        }

        tags[tagName] = {
          id: id,
          default: dfl,
          enums: enums,
          flags: flags,
        };
      } else if (keyword === "cap") {
        // Define capabilities

        if (
          i + 1 >= parsed.length ||
          !Array.isArray(parsed[i + 1]) ||
          parsed[i + 1].length < 1 ||
          !Array.isArray(parsed[i + 1][0])
        )
          return [
            parsed[i][1],
            parsed[i][2],
            "Capability definition is missing name.",
          ];
        let cap = parsed[++i];
        let capName = cap[0][0].toLowerCase();

        if (!_isValidName(capName))
          return [cap[0][1], cap[0][2], "Invalid capability name."];
        if (capName in RESERVED_WORDS)
          return [cap[0][1], cap[0][2], "Capability name is a reserved word."];

        if (capName in caps)
          return [
            cap[0][1],
            cap[0][2],
            "Multiple definition of capability name.",
          ];

        let capRules = [];
        let id = -1;
        let dfl = false;
        for (let k = 1; k < cap.length; ++k) {
          let dn =
            typeof cap[k][0] === "string" ? cap[k][0].toLowerCase() : null;
          if (dn === "id") {
            if (id >= 0)
              return [
                cap[k][1],
                cap[k][2],
                "Duplicate id directive in capability definition.",
              ];
            if (k + 1 >= cap.length)
              return [cap[k][1], cap[k][2], "Missing value for ID."];
            id = _parseNum(cap[++k][0]);
            if (id < 0 || id > 0xffffffff)
              return [
                cap[k - 1][1],
                cap[k - 1][2],
                "Invalid or out of range capability ID.",
              ];
            for (let cn in caps) {
              if (caps[cn].id === id)
                return [
                  cap[k - 1][1],
                  cap[k - 1][2],
                  "Duplicate capability ID.",
                ];
            }
          } else if (dn === "default") {
            dfl = true;
          } else {
            capRules.push(cap[k]);
          }
        }
        if (id < 0)
          return [
            cap[0][1],
            cap[0][2],
            "Capability definition is missing a numeric ID.",
          ];

        caps[capName] = {
          id: id,
          default: dfl,
          rules: capRules,
        };
      } else {
        baseRuleTree.push(parsed[i]);
      }
    }

    // Pass 3: render low-level ZeroTier rules arrays for capabilities and base.

    for (let capName in caps) {
      let r = [];
      let err = _renderActions(caps[capName].rules, r, macros, caps, tags, {});
      if (err !== null) return err;
      caps[capName].rules = r;
    }

    let err = _renderActions(baseRuleTree, rules, macros, caps, tags, {});
    if (err !== null) return err;

    return null;
  } catch (e) {
    console.log(e.stack);
    return [0, 0, "Unexpected exception: " + e.toString()];
  }
}

exports.compile = compile;
