mirror of
https://github.com/danog/dns.git
synced 2024-11-30 04:29:06 +01:00
605 lines
20 KiB
PHP
605 lines
20 KiB
PHP
<?php
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namespace Amp\Dns;
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use Amp\Cache\ArrayCache;
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use Amp\CoroutineResult;
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use Amp\Deferred;
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use Amp\Failure;
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use Amp\Success;
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use LibDNS\Decoder\DecoderFactory;
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use LibDNS\Encoder\EncoderFactory;
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use LibDNS\Messages\MessageFactory;
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use LibDNS\Messages\MessageTypes;
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use LibDNS\Records\QuestionFactory;
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/**
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* Resolve a DNS name to an IP address
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*
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* Upon success the returned promise resolves to an indexed array of the form:
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*
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* [string $recordValue, int $type, int $ttl]
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*
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* A null $ttl value indicates the DNS name was resolved from the cache or the
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* local hosts file.
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* $type being one constant from Amp\Dns\Record
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*
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* Options:
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*
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* - "server" | string Custom DNS server address in ip or ip:port format (Default: 8.8.8.8:53)
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* - "timeout" | int DNS server query timeout (Default: 3000ms)
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* - "hosts" | bool Use the hosts file (Default: true)
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* - "reload_hosts" | bool Reload the hosts file (Default: false), only active when no_hosts not true
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* - "cache" | bool Use local DNS cache when querying (Default: true)
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* - "types" | array Default: [Record::A, Record::AAAA] (only for resolve())
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* - "recurse" | bool Check for DNAME and CNAME records (always active for resolve(), Default: false for query())
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*
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* If the custom per-request "server" option is not present the resolver will
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* use the first nameserver in /etc/resolv.conf or default to Google's public
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* DNS servers on Windows or if /etc/resolv.conf is not found.
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*
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* @param string $name The hostname to resolve
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* @param array $options
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* @return \Amp\Promise
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* @TODO add boolean "clear_cache" option flag
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*/
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function resolve($name, array $options = []) {
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if (!$inAddr = @\inet_pton($name)) {
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if (__isValidHostName($name)) {
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$types = empty($options["types"]) ? [Record::A, Record::AAAA] : $options["types"];
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return __pipeResult(__recurseWithHosts($name, $types, $options), $types);
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} else {
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return new Failure(new ResolutionException("Cannot resolve; invalid host name"));
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}
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} else {
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return new Success([[$name, isset($inAddr[4]) ? Record::AAAA : Record::A, $ttl = null]]);
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}
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}
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/**
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* Query specific DNS records.
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*
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* @param string $name
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* @param int|int[] $type Use constants of Amp\Dns\Record
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* @param array $options
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* @return \Amp\Promise
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* @TODO document options
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*/
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function query($name, $type, array $options = []) {
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if (!$inAddr = @\inet_pton($name)) {
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if (__isValidHostName($name)) {
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$handler = __NAMESPACE__ . "\\" . (empty($options["recurse"]) ? "__doRecurse" : "__doResolve");
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$types = (array) $type;
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return __pipeResult(\Amp\resolve($handler($name, $types, $options)), $types);
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} else {
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return new Failure(new ResolutionException("Query failed; invalid host name"));
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}
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} else {
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return new Failure(new ResolutionException("Cannot query records from an IP address"));
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}
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}
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function __isValidHostName($name) {
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$pattern = "/^(?:[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9]){0,1})(?:\\.[a-z0-9][a-z0-9-]{0,61}[a-z0-9])*$/i";
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return !isset($name[253]) && \preg_match($pattern, $name);
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}
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// flatten $result while preserving order according to $types (append unspecified types for e.g. Record::ALL queries)
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function __pipeResult($promise, array $types) {
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return \Amp\pipe($promise, function (array $result) use ($types) {
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$retval = [];
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foreach ($types as $type) {
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if (isset($result[$type])) {
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$retval = \array_merge($retval, $result[$type]);
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unset($result[$type]);
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}
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}
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return $result ? \array_merge($retval, \call_user_func_array("array_merge", $result)) : $retval;
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});
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}
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function __recurseWithHosts($name, array $types, $options) {
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// Check for hosts file matches
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if (!isset($options["hosts"]) || $options["hosts"]) {
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static $hosts = null;
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if ($hosts === null || !empty($options["reload_hosts"])) {
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return \Amp\pipe(\Amp\resolve(__loadHostsFile()), function ($value) use (&$hosts, $name, $types, $options) {
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unset($options["reload_hosts"]); // avoid recursion
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$hosts = $value;
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return __recurseWithHosts($name, $types, $options);
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});
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}
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$result = [];
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if (in_array(Record::A, $types) && isset($hosts[Record::A][$name])) {
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$result[Record::A] = [[$hosts[Record::A][$name], Record::A, $ttl = null]];
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}
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if (in_array(Record::AAAA, $types) && isset($hosts[Record::AAAA][$name])) {
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$result[Record::AAAA] = [[$hosts[Record::AAAA][$name], Record::AAAA, $ttl = null]];
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}
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if ($result) {
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return new Success($result);
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}
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}
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return \Amp\resolve(__doRecurse($name, $types, $options));
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}
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function __doRecurse($name, array $types, $options) {
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if (array_intersect($types, [Record::CNAME, Record::DNAME])) {
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throw new ResolutionException("Cannot use recursion for CNAME and DNAME records");
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}
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$types = array_merge($types, [Record::CNAME, Record::DNAME]);
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$lookupName = $name;
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for ($i = 0; $i < 30; $i++) {
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$result = (yield \Amp\resolve(__doResolve($lookupName, $types, $options)));
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if (count($result) > isset($result[Record::CNAME]) + isset($result[Record::DNAME])) {
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unset($result[Record::CNAME], $result[Record::DNAME]);
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yield new CoroutineResult($result);
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return;
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}
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// @TODO check for potentially using recursion and iterate over *all* CNAME/DNAME
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// @FIXME check higher level for CNAME?
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foreach ([Record::CNAME, Record::DNAME] as $type) {
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if (isset($result[$type])) {
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list($lookupName) = $result[$type][0];
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}
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}
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}
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throw new ResolutionException("CNAME or DNAME chain too long (possible recursion?)");
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}
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function __doRequest($state, $uri, $name, $type) {
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$server = __loadExistingServer($state, $uri) ?: __loadNewServer($state, $uri);
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// Get the next available request ID
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do {
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$requestId = $state->requestIdCounter++;
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if ($state->requestIdCounter >= MAX_REQUEST_ID) {
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$state->requestIdCounter = 1;
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}
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} while (isset($state->pendingRequests[$requestId]));
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// Create question record
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$question = $state->questionFactory->create($type);
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$question->setName($name);
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// Create request message
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$request = $state->messageFactory->create(MessageTypes::QUERY);
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$request->getQuestionRecords()->add($question);
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$request->isRecursionDesired(true);
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$request->setID($requestId);
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// Encode request message
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$requestPacket = $state->encoder->encode($request);
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if (substr($uri, 0, 6) == "tcp://") {
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$requestPacket = pack("n", strlen($requestPacket)) . $requestPacket;
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}
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// Send request
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$bytesWritten = \fwrite($server->socket, $requestPacket);
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if ($bytesWritten === false || isset($packet[$bytesWritten])) {
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throw new ResolutionException(
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"Request send failed"
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);
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}
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$promisor = new Deferred;
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$server->pendingRequests[$requestId] = true;
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$state->pendingRequests[$requestId] = [$promisor, $name, $type, $uri];
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return $promisor->promise();
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}
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function __doResolve($name, array $types, $options) {
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static $state;
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$state = $state ?: (yield \Amp\resolve(__init()));
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if (empty($types)) {
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yield new CoroutineResult([]);
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return;
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}
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assert(array_reduce($types, function ($result, $val) {
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return $result && \is_int($val);
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}, true), 'The $types passed to DNS functions must all be integers (from \Amp\Dns\Record class)');
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$name = \strtolower($name);
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$result = [];
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// Check for cache hits
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if (!isset($options["cache"]) || $options["cache"]) {
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foreach ($types as $k => $type) {
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$cacheKey = "$name#$type";
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$cacheValue = (yield $state->arrayCache->get($cacheKey));
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if ($cacheValue !== null) {
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$result[$type] = $cacheValue;
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unset($types[$k]);
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}
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}
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if (empty($types)) {
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yield new CoroutineResult($result);
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return;
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}
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}
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$timeout = empty($options["timeout"]) ? $state->config["timeout"] : (int) $options["timeout"];
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if (empty($options["server"])) {
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if (empty($state->config["nameservers"])) {
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throw new ResolutionException("No nameserver specified in system config");
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}
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$uri = "udp://" . $state->config["nameservers"][0];
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} else {
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$uri = __parseCustomServerUri($options["server"]);
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}
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foreach ($types as $type) {
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$promises[] = __doRequest($state, $uri, $name, $type);
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}
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try {
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list( , $resultArr) = (yield \Amp\timeout(\Amp\some($promises), $timeout));
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foreach ($resultArr as $value) {
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$result += $value;
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}
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} catch (\Amp\TimeoutException $e) {
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if (substr($uri, 0, 6) == "tcp://") {
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throw new TimeoutException(
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"Name resolution timed out for {$name}"
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);
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} else {
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$options["server"] = \preg_replace("#[a-z.]+://#", "tcp://", $uri);
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yield new CoroutineResult(\Amp\resolve(__doResolve($name, $types, $options)));
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}
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} catch (ResolutionException $e) {
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if (empty($result)) { // if we have no cached results
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throw $e;
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}
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} catch (\RuntimeException $e) { // if all promises in Amp\some fail
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if (empty($result)) { // if we have no cached results
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throw new ResolutionException("All name resolution requests failed", 0, $e);
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}
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}
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yield new CoroutineResult($result);
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}
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function __init() {
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$state = new \StdClass;
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$state->messageFactory = new MessageFactory;
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$state->questionFactory = new QuestionFactory;
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$state->encoder = (new EncoderFactory)->create();
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$state->decoder = (new DecoderFactory)->create();
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$state->arrayCache = new ArrayCache;
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$state->requestIdCounter = 1;
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$state->pendingRequests = [];
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$state->serverIdMap = [];
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$state->serverUriMap = [];
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$state->serverIdTimeoutMap = [];
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$state->now = \time();
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$state->serverTimeoutWatcher = \Amp\repeat(function ($watcherId) use ($state) {
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$state->now = $now = \time();
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foreach ($state->serverIdTimeoutMap as $id => $expiry) {
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if ($now > $expiry) {
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__unloadServer($state, $id);
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}
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}
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if (empty($state->serverIdMap)) {
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\Amp\disable($watcherId);
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}
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}, 1000, $options = [
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"enable" => true,
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"keep_alive" => false,
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]);
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$state->config = (yield \Amp\resolve(__loadResolvConf()));
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yield new CoroutineResult($state);
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}
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/** @link http://man7.org/linux/man-pages/man5/resolv.conf.5.html */
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function __loadResolvConf($path = null) {
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$result = [
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"nameservers" => [
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"8.8.8.8:53",
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"8.8.4.4:53",
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],
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"timeout" => 3000,
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"attempts" => 2,
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];
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if (\stripos(PHP_OS, "win") !== 0) {
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$path = $path ?: "/etc/resolv.conf";
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try {
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$lines = explode("\n", (yield \Amp\File\get($path)));
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$result["nameservers"] = [];
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foreach ($lines as $line) {
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$line = \preg_split('#\s+#', $line, 2);
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if (\count($line) !== 2) {
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continue;
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}
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list($type, $value) = $line;
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if ($type === "nameserver") {
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$line[1] = trim($line[1]);
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$ip = @\inet_pton($line[1]);
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if ($ip === false) {
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continue;
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}
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$result["nameservers"][] = $line[1] . ":53";
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} elseif ($type === "options") {
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$optline = preg_split('#\s+#', $value, 2);
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if (\count($optline) !== 2) {
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continue;
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}
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// TODO: Respect the contents of the attempts setting during resolution
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list($option, $value) = $optline;
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if (in_array($option, ["timeout", "attempts"])) {
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$result[$option] = (int) $value;
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}
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}
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}
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} catch (\Amp\File\FilesystemException $e) {}
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}
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yield new CoroutineResult($result);
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}
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function __loadHostsFile($path = null) {
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$data = [];
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if (empty($path)) {
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$path = \stripos(PHP_OS, "win") === 0
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? 'C:\Windows\system32\drivers\etc\hosts'
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: '/etc/hosts';
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}
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try {
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$contents = (yield \Amp\File\get($path));
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} catch (\Exception $e) {
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yield new CoroutineResult($data);
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return;
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}
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$lines = \array_filter(\array_map("trim", \explode("\n", $contents)));
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foreach ($lines as $line) {
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if ($line[0] === "#") {
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continue;
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}
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$parts = \preg_split('/\s+/', $line);
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if (!($ip = @\inet_pton($parts[0]))) {
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continue;
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} elseif (isset($ip[4])) {
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$key = Record::AAAA;
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} else {
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$key = Record::A;
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}
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for ($i = 1, $l = \count($parts); $i < $l; $i++) {
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if (__isValidHostName($parts[$i])) {
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$data[$key][strtolower($parts[$i])] = $parts[0];
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}
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}
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}
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yield new CoroutineResult($data);
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}
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function __parseCustomServerUri($uri) {
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if (!\is_string($uri)) {
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throw new ResolutionException(
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'Invalid server address ($uri must be a string IP address, ' . gettype($uri) . " given)"
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);
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}
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if (strpos("://", $uri) !== false) {
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return $uri;
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}
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if (($colonPos = strrpos(":", $uri)) !== false) {
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$addr = \substr($uri, 0, $colonPos);
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$port = \substr($uri, $colonPos);
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} else {
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$addr = $uri;
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$port = 53;
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}
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$addr = trim($addr, "[]");
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if (!$inAddr = @\inet_pton($addr)) {
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throw new ResolutionException(
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'Invalid server $uri; string IP address required'
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);
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}
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return isset($inAddr[4]) ? "udp://[{$addr}]:{$port}" : "udp://{$addr}:{$port}";
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}
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function __loadExistingServer($state, $uri) {
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if (empty($state->serverUriMap[$uri])) {
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return null;
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}
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$server = $state->serverUriMap[$uri];
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if (\is_resource($server->socket)) {
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unset($state->serverIdTimeoutMap[$server->id]);
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\Amp\enable($server->watcherId);
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return $server;
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}
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__unloadServer($state, $server->id);
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return null;
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}
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function __loadNewServer($state, $uri) {
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if (!$socket = @\stream_socket_client($uri, $errno, $errstr)) {
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throw new ResolutionException(sprintf(
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"Connection to %s failed: [Error #%d] %s",
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$uri,
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$errno,
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$errstr
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));
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}
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\stream_set_blocking($socket, false);
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$id = (int) $socket;
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$server = new \StdClass;
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$server->id = $id;
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$server->uri = $uri;
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$server->socket = $socket;
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$server->buffer = "";
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$server->length = INF;
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$server->pendingRequests = [];
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$server->watcherId = \Amp\onReadable($socket, 'Amp\Dns\__onReadable', [
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"enable" => true,
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"keep_alive" => true,
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"cb_data" => $state,
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]);
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$state->serverIdMap[$id] = $server;
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$state->serverUriMap[$uri] = $server;
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return $server;
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}
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function __unloadServer($state, $serverId, $error = null) {
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$server = $state->serverIdMap[$serverId];
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\Amp\cancel($server->watcherId);
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unset(
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$state->serverIdMap[$serverId],
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$state->serverUriMap[$server->uri]
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);
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if (\is_resource($server->socket)) {
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@\fclose($server->socket);
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}
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if ($error && $server->pendingRequests) {
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foreach (array_keys($server->pendingRequests) as $requestId) {
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list($promisor) = $state->pendingRequests[$requestId];
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$promisor->fail($error);
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}
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}
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}
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function __onReadable($watcherId, $socket, $state) {
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$serverId = (int) $socket;
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$packet = @\fread($socket, 512);
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if ($packet != "") {
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$server = $state->serverIdMap[$serverId];
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if (\substr($server->uri, 0, 6) == "tcp://") {
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if ($server->length == INF) {
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$server->length = unpack("n", $packet)[1];
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$packet = substr($packet, 2);
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}
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$server->buffer .= $packet;
|
|
while ($server->length <= \strlen($server->buffer)) {
|
|
__decodeResponsePacket($state, $serverId, substr($server->buffer, 0, $server->length));
|
|
$server->buffer = substr($server->buffer, $server->length);
|
|
if (\strlen($server->buffer) >= 2 + $server->length) {
|
|
$server->length = unpack("n", $server->buffer)[1];
|
|
$server->buffer = substr($server->buffer, 2);
|
|
} else {
|
|
$server->length = INF;
|
|
}
|
|
}
|
|
} else {
|
|
__decodeResponsePacket($state, $serverId, $packet);
|
|
}
|
|
} else {
|
|
__unloadServer($state, $serverId, new ResolutionException(
|
|
"Server connection failed"
|
|
));
|
|
}
|
|
}
|
|
|
|
function __decodeResponsePacket($state, $serverId, $packet) {
|
|
try {
|
|
$response = $state->decoder->decode($packet);
|
|
$requestId = $response->getID();
|
|
$responseCode = $response->getResponseCode();
|
|
$responseType = $response->getType();
|
|
|
|
if ($responseCode !== 0) {
|
|
__finalizeResult($state, $serverId, $requestId, new ResolutionException(
|
|
"Server returned error code: {$responseCode}"
|
|
));
|
|
} elseif ($responseType !== MessageTypes::RESPONSE) {
|
|
__unloadServer($state, $serverId, new ResolutionException(
|
|
"Invalid server reply; expected RESPONSE but received QUERY"
|
|
));
|
|
} else {
|
|
__processDecodedResponse($state, $serverId, $requestId, $response);
|
|
}
|
|
} catch (\Exception $e) {
|
|
__unloadServer($state, $serverId, new ResolutionException(
|
|
"Response decode error", 0, $e
|
|
));
|
|
}
|
|
}
|
|
|
|
function __processDecodedResponse($state, $serverId, $requestId, $response) {
|
|
list($promisor, $name, $type, $uri) = $state->pendingRequests[$requestId];
|
|
|
|
// Retry via tcp if message has been truncated
|
|
if ($response->isTruncated()) {
|
|
if (\substr($uri, 0, 6) != "tcp://") {
|
|
$uri = \preg_replace("#[a-z.]+://#", "tcp://", $uri);
|
|
$promisor->succeed(__doRequest($state, $uri, $name, $type));
|
|
} else {
|
|
__finalizeResult($state, $serverId, $requestId, new ResolutionException(
|
|
"Server returned truncated response"
|
|
));
|
|
}
|
|
return;
|
|
}
|
|
|
|
$answers = $response->getAnswerRecords();
|
|
foreach ($answers as $record) {
|
|
$result[$record->getType()][] = [(string) $record->getData(), $record->getType(), $record->getTTL()];
|
|
}
|
|
if (empty($result)) {
|
|
$state->arrayCache->set("$name#$type", [], 300); // "it MUST NOT cache it for longer than five (5) minutes" per RFC 2308 section 7.1
|
|
__finalizeResult($state, $serverId, $requestId, new NoRecordException(
|
|
"No records returned for {$name}"
|
|
));
|
|
} else {
|
|
__finalizeResult($state, $serverId, $requestId, $error = null, $result);
|
|
}
|
|
}
|
|
|
|
function __finalizeResult($state, $serverId, $requestId, $error = null, $result = null) {
|
|
if (empty($state->pendingRequests[$requestId])) {
|
|
return;
|
|
}
|
|
|
|
list($promisor, $name) = $state->pendingRequests[$requestId];
|
|
$server = $state->serverIdMap[$serverId];
|
|
unset(
|
|
$state->pendingRequests[$requestId],
|
|
$server->pendingRequests[$requestId]
|
|
);
|
|
if (empty($server->pendingRequests)) {
|
|
$state->serverIdTimeoutMap[$server->id] = $state->now + IDLE_TIMEOUT;
|
|
\Amp\disable($server->watcherId);
|
|
\Amp\enable($state->serverTimeoutWatcher);
|
|
}
|
|
if ($error) {
|
|
$promisor->fail($error);
|
|
} else {
|
|
foreach ($result as $type => $records) {
|
|
$minttl = INF;
|
|
foreach ($records as list( , $ttl)) {
|
|
if ($ttl && $minttl > $ttl) {
|
|
$minttl = $ttl;
|
|
}
|
|
}
|
|
$state->arrayCache->set("$name#$type", $records, $minttl);
|
|
}
|
|
$promisor->succeed($result);
|
|
}
|
|
}
|