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'use strict';
const errors = require('internal/errors');
const { isIP } = require('internal/net');
const {
ChannelWrap,
strerror,
AI_ADDRCONFIG,
AI_V4MAPPED
} = internalBinding('cares_wrap');
const IANA_DNS_PORT = 53;
const IPv6RE = /^\[([^[\]]*)\]/;
const addrSplitRE = /(^.+?)(?::(\d+))?$/;
const {
ERR_DNS_SET_SERVERS_FAILED,
ERR_INVALID_ARG_TYPE,
ERR_INVALID_IP_ADDRESS,
ERR_INVALID_OPT_VALUE
} = errors.codes;
// Resolver instances correspond 1:1 to c-ares channels.
class Resolver {
constructor() {
this._handle = new ChannelWrap();
}
cancel() {
this._handle.cancel();
}
getServers() {
return this._handle.getServers().map((val) => {
if (!val[1] || val[1] === IANA_DNS_PORT)
return val[0];
const host = isIP(val[0]) === 6 ? `[${val[0]}]` : val[0];
return `${host}:${val[1]}`;
});
}
setServers(servers) {
if (!Array.isArray(servers)) {
throw new ERR_INVALID_ARG_TYPE('servers', 'Array', servers);
}
// Cache the original servers because in the event of an error while
// setting the servers, c-ares won't have any servers available for
// resolution.
const orig = this._handle.getServers();
const newSet = [];
servers.forEach((serv, index) => {
if (typeof serv !== 'string') {
throw new ERR_INVALID_ARG_TYPE(`servers[${index}]`, 'string', serv);
}
var ipVersion = isIP(serv);
if (ipVersion !== 0)
return newSet.push([ipVersion, serv, IANA_DNS_PORT]);
const match = serv.match(IPv6RE);
// Check for an IPv6 in brackets.
if (match) {
ipVersion = isIP(match[1]);
if (ipVersion !== 0) {
const port =
parseInt(serv.replace(addrSplitRE, '$2')) ||
IANA_DNS_PORT;
return newSet.push([ipVersion, match[1], port]);
}
}
// addr::port
const addrSplitMatch = serv.match(addrSplitRE);
if (addrSplitMatch) {
const hostIP = addrSplitMatch[1];
const port = addrSplitMatch[2] || IANA_DNS_PORT;
ipVersion = isIP(hostIP);
if (ipVersion !== 0) {
return newSet.push([ipVersion, hostIP, parseInt(port)]);
}
}
throw new ERR_INVALID_IP_ADDRESS(serv);
});
const errorNumber = this._handle.setServers(newSet);
if (errorNumber !== 0) {
// Reset the servers to the old servers, because ares probably unset them.
this._handle.setServers(orig.join(','));
const err = strerror(errorNumber);
throw new ERR_DNS_SET_SERVERS_FAILED(err, servers);
}
}
}
let defaultResolver = new Resolver();
const resolverKeys = [
'getServers',
'resolve',
'resolveAny',
'resolve4',
'resolve6',
'resolveCname',
'resolveMx',
'resolveNs',
'resolveTxt',
'resolveSrv',
'resolvePtr',
'resolveNaptr',
'resolveSoa',
'reverse'
];
function getDefaultResolver() {
return defaultResolver;
}
function setDefaultResolver(resolver) {
defaultResolver = resolver;
}
function bindDefaultResolver(target, source) {
resolverKeys.forEach((key) => {
target[key] = source[key].bind(defaultResolver);
});
}
function validateHints(hints) {
if (hints !== 0 &&
hints !== AI_ADDRCONFIG &&
hints !== AI_V4MAPPED &&
hints !== (AI_ADDRCONFIG | AI_V4MAPPED)) {
throw new ERR_INVALID_OPT_VALUE('hints', hints);
}
}
module.exports = {
bindDefaultResolver,
getDefaultResolver,
setDefaultResolver,
validateHints,
Resolver
};
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