Merge

lib/Config.php

@@ -4,10 +4,20 @@ namespace Amp\Dns;
 
 final class Config
 {
+    /** @var array */
     private $nameservers;
+    /** @var array */
     private $knownHosts;
+    /** @var int */
     private $timeout;
+    /** @var int */
     private $attempts;
+    /** @var array */
+    private $searchList = [];
+    /** @var int */
+    private $ndots = 1;
+    /** @var bool */
+    private $rotation = false;
 
     public function __construct(array $nameservers, array $knownHosts = [], int $timeout = 3000, int $attempts = 2)
     {
@@ -44,6 +54,39 @@ final class Config
         $this->attempts = $attempts;
     }
 
+    public function withSearchList(array $searchList): self
+    {
+        $self = clone $this;
+        $self->searchList = $searchList;
+
+        return $self;
+    }
+
+    /**
+     * @throws ConfigException
+     */
+    public function withNdots(int $ndots): self
+    {
+        if ($ndots < 0) {
+            throw new ConfigException("Invalid ndots ({$ndots}), must be greater or equal to 0");
+        }
+        if ($ndots > 15) {
+            $ndots = 15;
+        }
+        $self = clone $this;
+        $self->ndots = $ndots;
+
+        return $self;
+    }
+
+    public function withRotationEnabled(bool $enabled = true): self
+    {
+        $self = clone $this;
+        $self->rotation = $enabled;
+
+        return $self;
+    }
+
     private function validateNameserver($nameserver)
     {
         if (!$nameserver || !\is_string($nameserver)) {
@@ -101,4 +144,19 @@ final class Config
     {
         return $this->attempts;
     }
+
+    public function getSearchList(): array
+    {
+        return $this->searchList;
+    }
+
+    public function getNdots(): int
+    {
+        return $this->ndots;
+    }
+
+    public function isRotationEnabled(): bool
+    {
+        return $this->rotation;
+    }
 }

lib/Rfc1035StubResolver.php

@@ -55,6 +55,8 @@ final class Rfc1035StubResolver implements Resolver
 
     /** @var BlockingFallbackResolver */
     private $blockingFallbackResolver;
+    /** @var int */
+    private $nextNameserver = 0;
 
     public function __construct(Cache $cache = null, ConfigLoader $configLoader = null)
     {
@@ -135,7 +137,9 @@ final class Rfc1035StubResolver implements Resolver
                     }
                     break;
             }
-
+            $dots = \substr_count($name, ".");
+            // Should be replaced with $name[-1] from 7.1
+            $trailingDot = \substr($name, -1, 1) === ".";
             $name = normalizeName($name);
 
             if ($records = $this->queryHosts($name, $typeRestriction)) {
@@ -150,52 +154,69 @@ final class Rfc1035StubResolver implements Resolver
                     : [new Record('127.0.0.1', Record::A, null)];
             }
 
-            for ($redirects = 0; $redirects < 5; $redirects++) {
-                try {
-                    if ($typeRestriction) {
-                        return yield $this->query($name, $typeRestriction);
+            if (!$dots && \count($this->config->getSearchList()) === 0) {
+                throw new DnsException("Giving up resolution of '{$name}', unknown host");
+            }
+
+            $searchList = [null];
+            if (!$trailingDot && $dots < $this->config->getNdots()) {
+                $searchList = \array_merge($this->config->getSearchList(), $searchList);
+            }
+
+            foreach ($searchList as $search) {
+                for ($redirects = 0; $redirects < 5; $redirects++) {
+                    $searchName = $name;
+
+                    if ($search !== null) {
+                        $searchName = $name . "." . $search;
                     }
 
                     try {
-                        list(, $records) = yield Promise\some([
-                            $this->query($name, Record::A),
-                            $this->query($name, Record::AAAA),
-                        ]);
-
-                        return \array_merge(...$records);
-                    } catch (MultiReasonException $e) {
-                        $errors = [];
-
-                        foreach ($e->getReasons() as $reason) {
-                            if ($reason instanceof NoRecordException) {
-                                throw $reason;
-                            }
-
-                            $errors[] = $reason->getMessage();
+                        if ($typeRestriction) {
+                            return yield $this->query($searchName, $typeRestriction);
                         }
 
-                        throw new DnsException(
-                            "All query attempts failed for {$name}: " . \implode(", ", $errors),
-                            0,
-                            $e
-                        );
-                    }
-                } catch (NoRecordException $e) {
-                    try {
-                        /** @var Record[] $cnameRecords */
-                        $cnameRecords = yield $this->query($name, Record::CNAME);
-                        $name = $cnameRecords[0]->getValue();
-                        continue;
+                        try {
+                            list(, $records) = yield Promise\some([
+                                $this->query($searchName, Record::A),
+                                $this->query($searchName, Record::AAAA),
+                            ]);
+
+                            return \array_merge(...$records);
+                        } catch (MultiReasonException $e) {
+                            $errors = [];
+
+                            foreach ($e->getReasons() as $reason) {
+                                if ($reason instanceof NoRecordException) {
+                                    throw $reason;
+                                }
+
+                                $errors[] = $reason->getMessage();
+                            }
+
+                            throw new DnsException(
+                                "All query attempts failed for {$searchName}: " . \implode(", ", $errors),
+                                0,
+                                $e
+                            );
+                        }
                     } catch (NoRecordException $e) {
-                        /** @var Record[] $dnameRecords */
-                        $dnameRecords = yield $this->query($name, Record::DNAME);
-                        $name = $dnameRecords[0]->getValue();
-                        continue;
+                        try {
+                            /** @var Record[] $cnameRecords */
+                            $cnameRecords = yield $this->query($searchName, Record::CNAME);
+                            $name = $cnameRecords[0]->getValue();
+                            continue;
+                        } catch (NoRecordException $e) {
+                            /** @var Record[] $dnameRecords */
+                            $dnameRecords = yield $this->query($searchName, Record::DNAME);
+                            $name = $dnameRecords[0]->getValue();
+                            continue;
+                        }
                     }
                 }
             }
 
-            throw new DnsException("Giving up resolution of '{$name}', too many redirects");
+            throw new DnsException("Giving up resolution of '{$searchName}', too many redirects");
         });
     }
 
@@ -268,7 +289,8 @@ final class Rfc1035StubResolver implements Resolver
                 return $this->decodeCachedResult($name, $type, $cachedValue);
             }
 
-            $nameservers = $this->config->getNameservers();
+            $nameservers = $this->selectNameservers();
+            $nameserversCount = \count($nameservers);
             $attempts = $this->config->getAttempts();
             $protocol = "udp";
             $attempt = 0;
@@ -285,9 +307,7 @@ final class Rfc1035StubResolver implements Resolver
                         unset($this->sockets[$uri]);
                         $socket->close();
 
-                        /** @var Socket $server */
-                        $i = $attempt % \count($nameservers);
-                        $uri = $protocol . "://" . $nameservers[$i];
+                        $uri = $protocol . "://" . $nameservers[$attempt % $nameserversCount];
                         $socket = yield $this->getSocket($uri);
                     }
 
@@ -309,8 +329,7 @@ final class Rfc1035StubResolver implements Resolver
                         if ($protocol !== "tcp") {
                             // Retry with TCP, don't count attempt
                             $protocol = "tcp";
-                            $i = $attempt % \count($nameservers);
-                            $uri = $protocol . "://" . $nameservers[$i];
+                            $uri = $protocol . "://" . $nameservers[$attempt % $nameserversCount];
                             $socket = yield $this->getSocket($uri);
                             continue;
                         }
@@ -356,8 +375,7 @@ final class Rfc1035StubResolver implements Resolver
                         $socket->close();
                     });
 
-                    $i = ++$attempt % \count($nameservers);
-                    $uri = $protocol . "://" . $nameservers[$i];
+                    $uri = $protocol . "://" . $nameservers[++$attempt % $nameserversCount];
                     $socket = yield $this->getSocket($uri);
 
                     continue;
@@ -488,10 +506,28 @@ final class Rfc1035StubResolver implements Resolver
         return $server;
     }
 
+    /**
+     * @throws DnsException
+     */
     private function assertAcceptableResponse(Message $response)
     {
         if ($response->getResponseCode() !== 0) {
             throw new DnsException(\sprintf("Server returned error code: %d", $response->getResponseCode()));
         }
     }
+
+    private function selectNameservers(): array
+    {
+        $nameservers = $this->config->getNameservers();
+
+        if ($this->config->isRotationEnabled() && ($nameserversCount = \count($nameservers)) > 1) {
+            $nameservers = \array_merge(
+                \array_slice($nameservers, $this->nextNameserver),
+                \array_slice($nameservers, 0, $this->nextNameserver)
+            );
+            $this->nextNameserver = ++$this->nextNameserver % $nameserversCount;
+        }
+
+        return $nameservers;
+    }
 }

lib/UnixConfigLoader.php

@@ -9,6 +9,23 @@ use function Amp\call;
 
 class UnixConfigLoader implements ConfigLoader
 {
+    const MAX_NAMESERVERS = 3;
+    const MAX_DNS_SEARCH = 6;
+
+    const MAX_TIMEOUT = 30 * 1000;
+    const MAX_ATTEMPTS = 5;
+    const MAX_NDOTS = 15;
+
+    const DEFAULT_TIMEOUT = 5 * 1000;
+    const DEFAULT_ATTEMPTS = 2;
+    const DEFAULT_NDOTS = 1;
+
+    const DEFAULT_OPTIONS = [
+        "timeout" => self::DEFAULT_TIMEOUT,
+        "attempts" => self::DEFAULT_ATTEMPTS,
+        "ndots" => self::DEFAULT_NDOTS,
+        "rotate" => false,
+    ];
     private $path;
     private $hostLoader;
 
@@ -40,8 +57,20 @@ class UnixConfigLoader implements ConfigLoader
     {
         return call(function () {
             $nameservers = [];
-            $timeout = 3000;
-            $attempts = 2;
+            $searchList = [];
+            $options = self::DEFAULT_OPTIONS;
+            $haveLocaldomainEnv = false;
+
+            /* Allow user to override the local domain definition.  */
+            if ($localdomain = \getenv("LOCALDOMAIN")) {
+                /* Set search list to be blank-separated strings from rest of
+                   env value.  Permits users of LOCALDOMAIN to still have a
+                   search list, and anyone to set the one that they want to use
+                   as an individual (even more important now that the rfc1535
+                   stuff restricts searches).  */
+                $searchList = $this->splitOnWhitespace($localdomain);
+                $haveLocaldomainEnv = true;
+            }
 
             $fileContent = yield $this->readFile($this->path);
 
@@ -57,6 +86,9 @@ class UnixConfigLoader implements ConfigLoader
                 list($type, $value) = $line;
 
                 if ($type === "nameserver") {
+                    if (\count($nameservers) === self::MAX_NAMESERVERS) {
+                        continue;
+                    }
                     $value = \trim($value);
                     $ip = @\inet_pton($value);
 
@@ -69,29 +101,90 @@ class UnixConfigLoader implements ConfigLoader
                     } else { // IPv4
                         $nameservers[] = $value . ":53";
                     }
+                } elseif ($type === "domain" && !$haveLocaldomainEnv) { // LOCALDOMAIN env overrides config
+                    $searchList = $this->splitOnWhitespace($value);
+                } elseif ($type === "search" && !$haveLocaldomainEnv) { // LOCALDOMAIN env overrides config
+                    $searchList = $this->splitOnWhitespace($value);
                 } elseif ($type === "options") {
-                    $optline = \preg_split('#\s+#', $value, 2);
-
-                    if (\count($optline) !== 2) {
-                        continue;
-                    }
-
-                    list($option, $value) = $optline;
-
-                    switch ($option) {
-                        case "timeout":
-                            $timeout = (int) $value;
-                            break;
-
-                        case "attempts":
-                            $attempts = (int) $value;
+                    $option = $this->parseOption($value);
+                    if (\count($option) === 2) {
+                        $options[$option[0]] = $option[1];
                     }
                 }
             }
 
             $hosts = yield $this->hostLoader->loadHosts();
 
-            return new Config($nameservers, $hosts, $timeout, $attempts);
+            if (\count($searchList) === 0) {
+                $hostname = \gethostname();
+                $dot = \strpos(".", $hostname);
+                if ($dot !== false && $dot < \strlen($hostname)) {
+                    $searchList = [
+                        \substr($hostname, $dot),
+                    ];
+                }
+            }
+            if (\count($searchList) > self::MAX_DNS_SEARCH) {
+                $searchList = \array_slice($searchList, 0, self::MAX_DNS_SEARCH);
+            }
+
+            $resOptions = \getenv("RES_OPTIONS");
+            if ($resOptions) {
+                foreach ($this->splitOnWhitespace($resOptions) as $option) {
+                    $option = $this->parseOption($option);
+                    if (\count($option) === 2) {
+                        $options[$option[0]] = $option[1];
+                    }
+                }
+            }
+
+            $config = new Config($nameservers, $hosts, $options["timeout"], $options["attempts"]);
+
+            return $config->withSearchList($searchList)
+                ->withNdots($options["ndots"])
+                ->withRotationEnabled($options["rotate"]);
         });
     }
+
+    private function splitOnWhitespace(string $names): array
+    {
+        return \preg_split("#\s+#", \trim($names));
+    }
+
+    private function parseOption(string $option): array
+    {
+        $optline = \explode(':', $option, 2);
+        list($name, $value) = $optline + [1 => null];
+
+        switch ($name) {
+            case "timeout":
+                $value = (int) $value;
+                if ($value < 0) {
+                    return []; // don't overwrite option value
+                }
+                // The value for this option is silently capped to 30s
+                return ["timeout", (int) \min($value * 1000, self::MAX_TIMEOUT)];
+
+            case "attempts":
+                $value = (int) $value;
+                if ($value < 0) {
+                    return []; // don't overwrite option value
+                }
+                // The value for this option is silently capped to 5
+                return ["attempts", (int) \min($value, self::MAX_ATTEMPTS)];
+
+            case "ndots":
+                $value = (int) $value;
+                if ($value < 0) {
+                    return []; // don't overwrite option value
+                }
+                // The value for this option is silently capped to 15
+                return ["ndots", (int) \min($value, self::MAX_NDOTS)];
+
+            case "rotate":
+                return ["rotate", true];
+        }
+
+        return [];
+    }
 }

test/ConfigTest.php

@@ -74,4 +74,38 @@ class ConfigTest extends TestCase
         $this->expectException(ConfigException::class);
         new Config(["127.0.0.1"], [], 500, 0);
     }
+
+    public function testInvalidNtods()
+    {
+        $this->expectException(ConfigException::class);
+        $config = new Config(["127.0.0.1"]);
+        $config->withNdots(-1);
+    }
+
+    public function testNdots()
+    {
+        $config = new Config(["127.0.0.1"]);
+        $config = $config->withNdots(1);
+        $this->assertSame(1, $config->getNdots());
+    }
+
+    public function testSearchList()
+    {
+        $config = new Config(["127.0.0.1"]);
+        $config = $config->withSearchList(['local']);
+        $this->assertSame(['local'], $config->getSearchList());
+    }
+
+    public function testRotationEnabled()
+    {
+        $config = new Config(["127.0.0.1"]);
+        $config = $config->withRotationEnabled(true);
+        $this->assertTrue($config->isRotationEnabled());
+    }
+
+    public function testRotationDisabled()
+    {
+        $config = new Config(["127.0.0.1"]);
+        $this->assertFalse($config->isRotationEnabled());
+    }
 }

test/IntegrationTest.php

@@ -2,11 +2,17 @@
 
 namespace Amp\Dns\Test;
 
+use Amp\Cache\NullCache;
 use Amp\Dns;
 use Amp\Dns\BlockingFallbackResolver;
+use Amp\Dns\DnsException;
 use Amp\Dns\Record;
+use Amp\Dns\UnixConfigLoader;
+use Amp\Dns\WindowsConfigLoader;
 use Amp\Loop;
 use Amp\PHPUnit\TestCase;
+use Amp\Success;
+use PHPUnit\Framework\MockObject\MockObject;
 
 class IntegrationTest extends TestCase
 {
@@ -25,7 +31,7 @@ class IntegrationTest extends TestCase
             $inAddr = @\inet_pton($record->getValue());
             $this->assertNotFalse(
                 $inAddr,
-                "Server name $hostname did not resolve to a valid IP address"
+                "Server name {$hostname} did not resolve to a valid IP address"
             );
         });
     }
@@ -95,6 +101,87 @@ class IntegrationTest extends TestCase
         });
     }
 
+    public function testResolveUsingSearchList()
+    {
+        Loop::run(function () {
+            $configLoader = \stripos(PHP_OS, "win") === 0
+                ? new WindowsConfigLoader()
+                : new UnixConfigLoader();
+            /** @var Dns\Config $config */
+            $config = yield $configLoader->loadConfig();
+            $config = $config->withSearchList(['kelunik.com']);
+            $config = $config->withNdots(1);
+            /** @var Dns\ConfigLoader|MockObject $configLoader */
+            $configLoader = $this->createMock(Dns\ConfigLoader::class);
+            $configLoader->expects($this->once())
+                ->method('loadConfig')
+                ->willReturn(new Success($config));
+
+            Dns\resolver(new Dns\Rfc1035StubResolver(null, $configLoader));
+            $result = yield Dns\resolve('blog');
+
+            /** @var Record $record */
+            $record = $result[0];
+            $inAddr = @\inet_pton($record->getValue());
+            $this->assertNotFalse(
+                $inAddr,
+                "Server name blog.kelunik.com did not resolve to a valid IP address"
+            );
+
+            $result = yield Dns\query('blog.kelunik.com', Dns\Record::A);
+            /** @var Record $record */
+            $record = $result[0];
+            $this->assertSame($inAddr, @\inet_pton($record->getValue()));
+        });
+    }
+
+    public function testFailResolveRootedDomainWhenSearchListDefined()
+    {
+        Loop::run(function () {
+            $configLoader = \stripos(PHP_OS, "win") === 0
+                ? new WindowsConfigLoader()
+                : new UnixConfigLoader();
+            /** @var Dns\Config $config */
+            $config = yield $configLoader->loadConfig();
+            $config = $config->withSearchList(['kelunik.com']);
+            $config = $config->withNdots(1);
+            /** @var Dns\ConfigLoader|MockObject $configLoader */
+            $configLoader = $this->createMock(Dns\ConfigLoader::class);
+            $configLoader->expects($this->once())
+                ->method('loadConfig')
+                ->willReturn(new Success($config));
+
+            Dns\resolver(new Dns\Rfc1035StubResolver(null, $configLoader));
+            $this->expectException(DnsException::class);
+            yield Dns\resolve('blog.');
+        });
+    }
+
+    public function testResolveWithRotateList()
+    {
+        Loop::run(function () {
+            /** @var Dns\ConfigLoader|MockObject $configLoader */
+            $configLoader = $this->createMock(Dns\ConfigLoader::class);
+            $config = new Dns\Config([
+                '208.67.222.220:53', // Opendns, US
+                '195.243.214.4:53', // Deutche Telecom AG, DE
+            ]);
+            $config = $config->withRotationEnabled(true);
+            $configLoader->expects($this->once())
+                ->method('loadConfig')
+                ->willReturn(new Success($config));
+
+            $resolver = new Dns\Rfc1035StubResolver(new NullCache(), $configLoader);
+
+            /** @var Record $record1 */
+            list($record1) = yield $resolver->query('facebook.com', Dns\Record::A);
+            /** @var Record $record2 */
+            list($record2) = yield $resolver->query('facebook.com', Dns\Record::A);
+
+            $this->assertNotSame($record1->getValue(), $record2->getValue());
+        });
+    }
+
     public function testPtrLookup()
     {
         Loop::run(function () {
@@ -179,6 +266,7 @@ class IntegrationTest extends TestCase
             ["localhost"],
             ["192.168.0.1"],
             ["::1"],
+            ["dns.google."], /* that's rooted domain name - cannot use searchList */
         ];
     }
 

test/UnixConfigLoaderTest.php

@@ -22,8 +22,87 @@ class UnixConfigLoaderTest extends TestCase
             "[2001:4860:4860::8888]:53",
         ], $result->getNameservers());
 
-        $this->assertSame(5000, $result->getTimeout());
+        $this->assertSame(30000, $result->getTimeout());
         $this->assertSame(3, $result->getAttempts());
+        $this->assertEmpty($result->getSearchList());
+        $this->assertSame(1, $result->getNdots());
+        $this->assertFalse($result->isRotationEnabled());
+    }
+
+    public function testWithSearchList()
+    {
+        $loader = new UnixConfigLoader(__DIR__ . "/data/resolv-search.conf");
+
+        /** @var Config $result */
+        $result = wait($loader->loadConfig());
+
+        $this->assertSame([
+            "127.0.0.1:53",
+            "[2001:4860:4860::8888]:53",
+        ], $result->getNameservers());
+
+        $this->assertSame(30000, $result->getTimeout());
+        $this->assertSame(3, $result->getAttempts());
+        $this->assertSame(['local', 'local1', 'local2', 'local3', 'local4', 'local5'], $result->getSearchList());
+        $this->assertSame(15, $result->getNdots());
+        $this->assertFalse($result->isRotationEnabled());
+    }
+
+    public function testWithRotateOption()
+    {
+        $loader = new UnixConfigLoader(__DIR__ . "/data/resolv-rotate.conf");
+
+        /** @var Config $result */
+        $result = wait($loader->loadConfig());
+
+        $this->assertSame([
+            "127.0.0.1:53",
+            "[2001:4860:4860::8888]:53",
+        ], $result->getNameservers());
+
+        $this->assertSame(5000, $result->getTimeout());
+        $this->assertSame(2, $result->getAttempts());
+        $this->assertTrue($result->isRotationEnabled());
+    }
+
+    public function testWithNegativeOption()
+    {
+        $loader = new UnixConfigLoader(__DIR__ . "/data/resolv-negative-option-values.conf");
+
+        /** @var Config $result */
+        $result = wait($loader->loadConfig());
+
+        $this->assertSame([
+            "127.0.0.1:53",
+            "[2001:4860:4860::8888]:53",
+        ], $result->getNameservers());
+
+        $this->assertSame(5000, $result->getTimeout());
+        $this->assertSame(2, $result->getAttempts());
+        $this->assertSame(1, $result->getNdots());
+    }
+
+    public function testWithEnvironmentOverride()
+    {
+        \putenv("LOCALDOMAIN=local");
+        \putenv("RES_OPTIONS=timeout:1 attempts:10 ndots:10 rotate");
+
+        $loader = new UnixConfigLoader(__DIR__ . "/data/resolv.conf");
+
+        /** @var Config $result */
+        $result = wait($loader->loadConfig());
+
+        $this->assertSame([
+            "127.0.0.1:53",
+            "[2001:4860:4860::8888]:53",
+        ], $result->getNameservers());
+
+        $this->assertSame(['local'], $result->getSearchList());
+
+        $this->assertSame(1000, $result->getTimeout());
+        $this->assertSame(5, $result->getAttempts());
+        $this->assertSame(10, $result->getNdots());
+        $this->assertTrue($result->isRotationEnabled());
     }
 
     public function testNoDefaultsOnConfNotFound()

test/data/resolv-negative-option-values.conf

@@ -0,0 +1,9 @@
+# Default
+nameserver 127.0.0.1
+
+# Google Fallback
+nameserver 2001:4860:4860::8888
+
+options timeout:-1
+options attempts:-1
+options ndots:-1

test/data/resolv-rotate.conf

@@ -0,0 +1,10 @@
+# Default
+nameserver 127.0.0.1
+
+# Google Fallback
+nameserver 2001:4860:4860::8888
+
+# Invalid server gets ignored
+nameserver foobar
+
+options rotate

test/data/resolv-search.conf

@@ -0,0 +1,17 @@
+# Default
+nameserver 127.0.0.1
+
+# Google Fallback
+nameserver 2001:4860:4860::8888
+
+# Invalid server gets ignored
+nameserver foobar
+
+search local local1 local2 local3 local4 local5 local6
+
+options timeout:5000
+options attempts:3
+options ndots:20
+
+# Unknown option gets ignored
+options foo

test/data/resolv.conf

@@ -7,8 +7,8 @@ nameserver 2001:4860:4860::8888
 # Invalid server gets ignored
 nameserver foobar
 
-options timeout 5000
-options attempts 3
+options timeout:5000
+options attempts:3
 
 # Unknown option gets ignored
-options foo
+options foo