/*
* Copyright (c) 2008-2024 Jonathan Schleifer <js@nil.im>
*
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License version 3.0 only,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* version 3.0 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3.0 along with this program. If not, see
* <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <string.h>
#import "OFDNSResolver.h"
#import "OFArray.h"
#import "OFDNSQuery.h"
#import "OFDNSResolverSettings.h"
#import "OFDNSResponse.h"
#import "OFData.h"
#import "OFDate.h"
#import "OFDictionary.h"
#import "OFHostAddressResolver.h"
#import "OFNumber.h"
#import "OFPair.h"
#import "OFString.h"
#import "OFTCPSocket.h"
#import "OFTimer.h"
#import "OFUDPSocket.h"
#import "OFUDPSocket+Private.h"
#import "OFDNSQueryFailedException.h"
#import "OFInitializationFailedException.h"
#import "OFInvalidArgumentException.h"
#import "OFInvalidFormatException.h"
#import "OFInvalidServerResponseException.h"
#import "OFNotImplementedException.h"
#import "OFOutOfRangeException.h"
#import "OFTruncatedDataException.h"
#ifndef SOCK_DNS
# define SOCK_DNS 0
#endif
static const size_t bufferLength = OFDNSResolverBufferLength;
static const size_t maxDNSResponseLength = 65536;
/*
* RFC 1035 doesn't specify if pointers to pointers are allowed, and if so how
* many. Since it's unspecified, we have to assume that it might happen, but we
* also want to limit it to avoid DoS. Limiting it to 16 levels of pointers and
* immediately rejecting pointers to itself seems like a fair balance.
*/
static const uint_fast8_t maxAllowedPointers = 16;
@interface OFDNSResolver () <OFUDPSocketDelegate, OFTCPSocketDelegate>
- (void)of_contextTimedOut: (OFDNSResolverContext *)context;
@end
OF_DIRECT_MEMBERS
@interface OFDNSResolverContext: OFObject
{
@public
OFDNSQuery *_query;
OFNumber *_ID;
OFDNSResolverSettings *_settings;
size_t _nameServersIndex;
unsigned int _attempt;
id <OFDNSResolverQueryDelegate> _delegate;
OFData *_queryData;
OFSocketAddress _usedNameServer;
OFTCPSocket *_TCPSocket;
OFMutableData *_TCPQueryData;
void *_TCPBuffer;
size_t _responseLength;
OFTimer *_cancelTimer;
}
- (instancetype)initWithQuery: (OFDNSQuery *)query
ID: (OFNumber *)ID
settings: (OFDNSResolverSettings *)settings
delegate: (id <OFDNSResolverQueryDelegate>)delegate;
@end
static OFString *
parseString(const unsigned char *buffer, size_t length, size_t *i)
{
uint8_t stringLength;
OFString *string;
if (*i >= length)
@throw [OFTruncatedDataException exception];
stringLength = buffer[(*i)++];
if (*i + stringLength > length)
@throw [OFTruncatedDataException exception];
string = [OFString stringWithUTF8String: (char *)&buffer[*i]
length: stringLength];
*i += stringLength;
return string;
}
static OFString *
parseName(const unsigned char *buffer, size_t length, size_t *i,
uint_fast8_t pointerLevel)
{
OFMutableArray *components = [OFMutableArray array];
uint8_t componentLength;
do {
OFString *component;
if (*i >= length)
@throw [OFTruncatedDataException exception];
componentLength = buffer[(*i)++];
if (componentLength & 0xC0) {
size_t j;
OFString *suffix;
if (pointerLevel == 0)
@throw [OFInvalidServerResponseException
exception];
if (*i >= length)
@throw [OFTruncatedDataException exception];
j = ((componentLength & 0x3F) << 8) | buffer[(*i)++];
if (j == *i - 2)
/* Pointing to itself?! */
@throw [OFInvalidServerResponseException
exception];
suffix = parseName(buffer, length, &j,
pointerLevel - 1);
if (components.count == 0)
return suffix;
else {
[components addObject: suffix];
return [components
componentsJoinedByString: @"."];
}
}
if (*i + componentLength > length)
@throw [OFTruncatedDataException exception];
component = [OFString stringWithUTF8String: (char *)&buffer[*i]
length: componentLength];
*i += componentLength;
[components addObject: component];
} while (componentLength > 0);
return [components componentsJoinedByString: @"."];
}
static OF_KINDOF(OFDNSResourceRecord *)
parseResourceRecord(OFString *name, OFDNSClass DNSClass,
OFDNSRecordType recordType, uint32_t TTL, const unsigned char *buffer,
size_t length, size_t i, uint16_t dataLength)
{
if (recordType == OFDNSRecordTypeA && DNSClass == OFDNSClassIN) {
OFSocketAddress address;
if (dataLength != 4)
@throw [OFInvalidServerResponseException exception];
memset(&address, 0, sizeof(address));
address.family = OFSocketAddressFamilyIPv4;
address.length = sizeof(address.sockaddr.in);
address.sockaddr.in.sin_family = AF_INET;
memcpy(&address.sockaddr.in.sin_addr.s_addr, buffer + i, 4);
return [[[OFADNSResourceRecord alloc]
initWithName: name
address: &address
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeNS) {
size_t j = i;
OFString *authoritativeHost = parseName(buffer, length, &j,
maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFNSDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
authoritativeHost: authoritativeHost
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeCNAME) {
size_t j = i;
OFString *alias = parseName(buffer, length, &j,
maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFCNAMEDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
alias: alias
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeSOA) {
size_t j = i;
OFString *primaryNameServer = parseName(buffer, length, &j,
maxAllowedPointers);
OFString *responsiblePerson;
uint32_t serialNumber, refreshInterval, retryInterval;
uint32_t expirationInterval, minTTL;
if (j > i + dataLength)
@throw [OFInvalidServerResponseException exception];
responsiblePerson = parseName(buffer, length, &j,
maxAllowedPointers);
if (dataLength - (j - i) != 20)
@throw [OFInvalidServerResponseException exception];
serialNumber = (buffer[j] << 24) | (buffer[j + 1] << 16) |
(buffer[j + 2] << 8) | buffer[j + 3];
refreshInterval = (buffer[j + 4] << 24) |
(buffer[j + 5] << 16) | (buffer[j + 6] << 8) |
buffer[j + 7];
retryInterval = (buffer[j + 8] << 24) | (buffer[j + 9] << 16) |
(buffer[j + 10] << 8) | buffer[j + 11];
expirationInterval = (buffer[j + 12] << 24) |
(buffer[j + 13] << 16) | (buffer[j + 14] << 8) |
buffer[j + 15];
minTTL = (buffer[j + 16] << 24) | (buffer[j + 17] << 16) |
(buffer[j + 18] << 8) | buffer[j + 19];
return [[[OFSOADNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
primaryNameServer: primaryNameServer
responsiblePerson: responsiblePerson
serialNumber: serialNumber
refreshInterval: refreshInterval
retryInterval: retryInterval
expirationInterval: expirationInterval
minTTL: minTTL
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypePTR) {
size_t j = i;
OFString *domainName = parseName(buffer, length, &j,
maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFPTRDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
domainName: domainName
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeHINFO) {
size_t j = i;
OFString *CPU = parseString(buffer, length, &j);
OFString *OS;
if (j > i + dataLength)
@throw [OFInvalidServerResponseException exception];
OS = parseString(buffer, length, &j);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFHINFODNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
CPU: CPU
OS: OS
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeMX) {
uint16_t preference;
size_t j;
OFString *mailExchange;
if (dataLength < 2)
@throw [OFInvalidServerResponseException exception];
preference = (buffer[i] << 8) | buffer[i + 1];
j = i + 2;
mailExchange = parseName(buffer, length, &j,
maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFMXDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
preference: preference
mailExchange: mailExchange
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeTXT) {
OFMutableArray *textStrings = [OFMutableArray array];
while (dataLength > 0) {
uint_fast8_t stringLength = buffer[i++];
dataLength--;
if (stringLength > dataLength)
@throw [OFInvalidServerResponseException
exception];
[textStrings addObject:
[OFData dataWithItems: buffer + i
count: stringLength]];
i += stringLength;
dataLength -= stringLength;
}
[textStrings makeImmutable];
return [[[OFTXTDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
textStrings: textStrings
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeRP) {
size_t j = i;
OFString *mailbox = parseName(buffer, length, &j,
maxAllowedPointers);
OFString *TXTDomainName;
if (j > i + dataLength)
@throw [OFInvalidServerResponseException exception];
TXTDomainName = parseName(buffer, length, &j,
maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFRPDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
mailbox: mailbox
TXTDomainName: TXTDomainName
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeAAAA &&
DNSClass == OFDNSClassIN) {
OFSocketAddress address;
if (dataLength != 16)
@throw [OFInvalidServerResponseException exception];
memset(&address, 0, sizeof(address));
address.family = OFSocketAddressFamilyIPv6;
address.length = sizeof(address.sockaddr.in6);
#ifdef AF_INET6
address.sockaddr.in6.sin6_family = AF_INET6;
#else
address.sockaddr.in6.sin6_family = AF_UNSPEC;
#endif
memcpy(address.sockaddr.in6.sin6_addr.s6_addr, buffer + i, 16);
return [[[OFAAAADNSResourceRecord alloc]
initWithName: name
address: &address
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeLOC) {
uint8_t size, horizontalPrecision, verticalPrecision;
uint32_t latitude, longitude, altitude;
if (dataLength < 16 || buffer[i] != 0)
@throw [OFInvalidServerResponseException exception];
size = buffer[i + 1];
horizontalPrecision = buffer[i + 2];
verticalPrecision = buffer[i + 3];
latitude = (buffer[i + 4] << 24) | (buffer[i + 5] << 16) |
(buffer[i + 6] << 8) | buffer[i + 7];
longitude = (buffer[i + 8] << 24) | (buffer[i + 9] << 16) |
(buffer[i + 10] << 8) | buffer[i + 11];
altitude = (buffer[i + 12] << 24) | (buffer[i + 13] << 16) |
(buffer[i + 14] << 8) | buffer[i + 15];
return [[[OFLOCDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
size: size
horizontalPrecision: horizontalPrecision
verticalPrecision: verticalPrecision
latitude: latitude
longitude: longitude
altitude: altitude
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeSRV &&
DNSClass == OFDNSClassIN) {
uint16_t priority, weight, port;
size_t j;
OFString *target;
if (dataLength < 6)
@throw [OFInvalidServerResponseException exception];
priority = (buffer[i] << 8) | buffer[i + 1];
weight = (buffer[i + 2] << 8) | buffer[i + 3];
port = (buffer[i + 4] << 8) | buffer[i + 5];
j = i + 6;
target = parseName(buffer, length, &j, maxAllowedPointers);
if (j != i + dataLength)
@throw [OFInvalidServerResponseException exception];
return [[[OFSRVDNSResourceRecord alloc]
initWithName: name
priority: priority
weight: weight
target: target
port: port
TTL: TTL] autorelease];
} else if (recordType == OFDNSRecordTypeURI) {
uint16_t priority, weight;
OFString *target;
if (dataLength < 4)
@throw [OFInvalidServerResponseException exception];
priority = (buffer[i] << 8) | buffer[i + 1];
weight = (buffer[i + 2] << 8) | buffer[i + 3];
target = [OFString stringWithUTF8String: (char *)buffer + i + 4
length: dataLength - 4];
return [[[OFURIDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
priority: priority
weight: weight
target: target
TTL: TTL] autorelease];
} else
return [[[OFDNSResourceRecord alloc]
initWithName: name
DNSClass: DNSClass
recordType: recordType
TTL: TTL] autorelease];
}
static OFDictionary *
parseSection(const unsigned char *buffer, size_t length, size_t *i,
uint_fast16_t count)
{
OFMutableDictionary *ret = [OFMutableDictionary dictionary];
OFEnumerator OF_GENERIC(OFMutableArray *) *objectEnumerator;
OFMutableArray *array;
for (uint_fast16_t j = 0; j < count; j++) {
OFString *name = parseName(buffer, length, i,
maxAllowedPointers).lowercaseString;
OFDNSClass DNSClass;
OFDNSRecordType recordType;
uint32_t TTL;
uint16_t dataLength;
OFDNSResourceRecord *record;
if (*i + 10 > length)
@throw [OFTruncatedDataException exception];
recordType = (buffer[*i] << 8) | buffer[*i + 1];
DNSClass = (buffer[*i + 2] << 8) | buffer[*i + 3];
TTL = (buffer[*i + 4] << 24) | (buffer[*i + 5] << 16) |
(buffer[*i + 6] << 8) | buffer[*i + 7];
dataLength = (buffer[*i + 8] << 8) | buffer[*i + 9];
*i += 10;
if (*i + dataLength > length)
@throw [OFTruncatedDataException exception];
record = parseResourceRecord(name, DNSClass, recordType, TTL,
buffer, length, *i, dataLength);
*i += dataLength;
array = [ret objectForKey: name];
if (array == nil) {
array = [OFMutableArray array];
[ret setObject: array forKey: name];
}
[array addObject: record];
}
objectEnumerator = [ret objectEnumerator];
while ((array = [objectEnumerator nextObject]) != nil)
[array makeImmutable];
[ret makeImmutable];
return ret;
}
static bool
containsExpiredRecord(OFDNSResponseRecords responseRecords, uint32_t age)
{
OFEnumerator *enumerator = [responseRecords objectEnumerator];
OFArray OF_GENERIC(OFDNSResourceRecord *) *records;
while ((records = [enumerator nextObject]) != nil)
for (OFDNSResourceRecord *record in records)
if (record.TTL < age)
return true;
return false;
}
@implementation OFDNSResolverContext
- (instancetype)initWithQuery: (OFDNSQuery *)query
ID: (OFNumber *)ID
settings: (OFDNSResolverSettings *)settings
delegate: (id <OFDNSResolverQueryDelegate>)delegate
{
self = [super init];
@try {
void *pool = objc_autoreleasePoolPush();
OFMutableData *queryData;
uint16_t tmp;
_query = [query copy];
_ID = [ID retain];
_settings = [settings copy];
_delegate = [delegate retain];
queryData = [OFMutableData dataWithCapacity: 512];
/* Header */
tmp = OFToBigEndian16(_ID.unsignedShortValue);
[queryData addItems: &tmp count: 2];
/* RD */
tmp = OFToBigEndian16(1u << 8);
[queryData addItems: &tmp count: 2];
/* QDCOUNT */
tmp = OFToBigEndian16(1);
[queryData addItems: &tmp count: 2];
/* ANCOUNT, NSCOUNT and ARCOUNT */
[queryData increaseCountBy: 6];
/* Question */
/* QNAME */
for (OFString *component in
[_query.domainName componentsSeparatedByString: @"."]) {
size_t length = component.UTF8StringLength;
uint8_t length8;
if (length > 63 || queryData.count + length > 512)
@throw [OFOutOfRangeException exception];
length8 = (uint8_t)length;
[queryData addItem: &length8];
[queryData addItems: component.UTF8String
count: length];
}
/* QTYPE */
tmp = OFToBigEndian16(_query.recordType);
[queryData addItems: &tmp count: 2];
/* QCLASS */
tmp = OFToBigEndian16(_query.DNSClass);
[queryData addItems: &tmp count: 2];
[queryData makeImmutable];
_queryData = [queryData copy];
objc_autoreleasePoolPop(pool);
} @catch (id e) {
[self release];
@throw e;
}
return self;
}
- (void)dealloc
{
[_query release];
[_ID release];
[_settings release];
[_delegate release];
[_queryData release];
[_TCPSocket release];
[_TCPQueryData release];
OFFreeMemory(_TCPBuffer);
[_cancelTimer release];
[super dealloc];
}
@end
@implementation OFDNSResolver
#ifdef OF_AMIGAOS
+ (void)initialize
{
if (self != [OFDNSResolver class])
return;
if (!_OFSocketInit())
@throw [OFInitializationFailedException
exceptionWithClass: self];
}
#endif
+ (instancetype)resolver
{
return [[[self alloc] init] autorelease];
}
- (instancetype)init
{
self = [super init];
@try {
_settings = [[OFDNSResolverSettings alloc] init];
_queries = [[OFMutableDictionary alloc] init];
_TCPQueries = [[OFMutableDictionary alloc] init];
_cache = [[OFMutableDictionary alloc] init];
[_settings reload];
} @catch (id e) {
[self release];
@throw e;
}
return self;
}
- (void)dealloc
{
[self close];
[_settings release];
[_IPv4Socket cancelAsyncRequests];
[_IPv4Socket release];
#ifdef OF_HAVE_IPV6
[_IPv6Socket cancelAsyncRequests];
[_IPv6Socket release];
#endif
[_queries release];
[_TCPQueries release];
[_cache release];
[_lastNameServers release];
[super dealloc];
}
- (OFDictionary *)staticHosts
{
return _settings->_staticHosts;
}
- (void)setStaticHosts: (OFDictionary *)staticHosts
{
OFDictionary *old = _settings->_staticHosts;
_settings->_staticHosts = [staticHosts copy];
[old release];
}
- (OFArray *)nameServers
{
return _settings->_nameServers;
}
- (void)setNameServers: (OFArray *)nameServers
{
OFArray *old = _settings->_nameServers;
_settings->_nameServers = [nameServers copy];
[old release];
}
- (OFString *)localDomain
{
return _settings->_localDomain;
}
- (OFArray *)searchDomains
{
return _settings->_searchDomains;
}
- (void)setSearchDomains: (OFArray *)searchDomains
{
OFArray *old = _settings->_searchDomains;
_settings->_searchDomains = [searchDomains copy];
[old release];
}
- (OFTimeInterval)timeout
{
return _settings->_timeout;
}
- (void)setTimeout: (OFTimeInterval)timeout
{
_settings->_timeout = timeout;
}
- (unsigned int)maxAttempts
{
return _settings->_maxAttempts;
}
- (void)setMaxAttempts: (unsigned int)maxAttempts
{
_settings->_maxAttempts = maxAttempts;
}
- (unsigned int)minNumberOfDotsInAbsoluteName
{
return _settings->_minNumberOfDotsInAbsoluteName;
}
- (void)setMinNumberOfDotsInAbsoluteName:
(unsigned int)minNumberOfDotsInAbsoluteName
{
_settings->_minNumberOfDotsInAbsoluteName =
minNumberOfDotsInAbsoluteName;
}
- (bool)forcesTCP
{
return _settings->_forcesTCP;
}
- (void)setForcesTCP: (bool)forcesTCP
{
_settings->_forcesTCP = forcesTCP;
}
- (OFTimeInterval)configReloadInterval
{
return _settings->_configReloadInterval;
}
- (void)setConfigReloadInterval: (OFTimeInterval)configReloadInterval
{
_settings->_configReloadInterval = configReloadInterval;
}
- (void)of_sendQueryForContext: (OFDNSResolverContext *)context
runLoopMode: (OFRunLoopMode)runLoopMode
{
OFUDPSocket *sock;
OFString *nameServer;
[_queries setObject: context forKey: context->_ID];
[context->_cancelTimer invalidate];
[context->_cancelTimer release];
context->_cancelTimer = nil;
context->_cancelTimer = [[OFTimer alloc]
initWithFireDate: [OFDate dateWithTimeIntervalSinceNow:
context->_settings->_timeout]
interval: context->_settings->_timeout
target: self
selector: @selector(of_contextTimedOut:)
object: context
repeats: false];
[[OFRunLoop currentRunLoop] addTimer: context->_cancelTimer
forMode: runLoopMode];
nameServer = [context->_settings->_nameServers
objectAtIndex: context->_nameServersIndex];
if (context->_settings->_forcesTCP) {
OFEnsure(context->_TCPSocket == nil);
context->_TCPSocket = [[OFTCPSocket alloc] init];
[_TCPQueries setObject: context forKey: context->_TCPSocket];
context->_TCPSocket.delegate = self;
[context->_TCPSocket asyncConnectToHost: nameServer
port: 53
runLoopMode: runLoopMode];
return;
}
context->_usedNameServer = OFSocketAddressParseIP(nameServer, 53);
switch (context->_usedNameServer.family) {
#ifdef OF_HAVE_IPV6
case OFSocketAddressFamilyIPv6:
if (_IPv6Socket == nil) {
OFSocketAddress address =
OFSocketAddressParseIPv6(@"::", 0);
_IPv6Socket = [[OFUDPSocket alloc] init];
[_IPv6Socket of_bindToAddress: &address
extraType: SOCK_DNS];
@try {
_IPv6Socket.canBlock = false;
} @catch (OFNotImplementedException *e) {
/* Can't do anything about it... */
}
_IPv6Socket.delegate = self;
}
sock = _IPv6Socket;
break;
#endif
case OFSocketAddressFamilyIPv4:
if (_IPv4Socket == nil) {
OFSocketAddress address =
OFSocketAddressParseIPv4(@"0.0.0.0", 0);
_IPv4Socket = [[OFUDPSocket alloc] init];
[_IPv4Socket of_bindToAddress: &address
extraType: SOCK_DNS];
@try {
_IPv4Socket.canBlock = false;
} @catch (OFNotImplementedException *e) {
/* Can't do anything about it... */
}
_IPv4Socket.delegate = self;
}
sock = _IPv4Socket;
break;
default:
@throw [OFInvalidArgumentException exception];
}
[sock asyncSendData: context->_queryData
receiver: &context->_usedNameServer
runLoopMode: runLoopMode];
[sock asyncReceiveIntoBuffer: _buffer
length: bufferLength
runLoopMode: runLoopMode];
}
- (void)of_cleanUpCache
{
OFTimeInterval now = [[OFDate date] timeIntervalSince1970];
OFMutableArray *removeList;
if (_lastNameServers != _settings->_nameServers &&
![_lastNameServers isEqual: _settings->_nameServers]) {
OFArray *old = _lastNameServers;
_lastNameServers = [_settings->_nameServers copy];
[old release];
[_cache removeAllObjects];
return;
}
if (now - _lastCacheCleanup < 1)
return;
_lastCacheCleanup = now;
removeList = [OFMutableArray arrayWithCapacity: _cache.count];
for (OFDNSQuery *query in _cache) {
OFPair OF_GENERIC(OFDate *, OFDNSResponse *) *entry =
[_cache objectForKey: query];
uint32_t age = (uint32_t)now -
(uint32_t)[entry.firstObject timeIntervalSince1970];
OFDNSResponse *response = entry.secondObject;
if (containsExpiredRecord(response.answerRecords, age) ||
containsExpiredRecord(response.authorityRecords, age) ||
containsExpiredRecord(response.additionalRecords, age))
[removeList addObject: query];
}
for (OFDNSQuery *query in removeList)
[_cache removeObjectForKey: query];
}
- (void)asyncPerformQuery: (OFDNSQuery *)query
delegate: (id <OFDNSResolverQueryDelegate>)delegate
{
[self asyncPerformQuery: query
runLoopMode: OFDefaultRunLoopMode
delegate: delegate];
}
- (void)asyncPerformQuery: (OFDNSQuery *)query
runLoopMode: (OFRunLoopMode)runLoopMode
delegate: (id <OFDNSResolverQueryDelegate>)delegate
{
void *pool = objc_autoreleasePoolPush();
OFNumber *ID;
OFDNSResolverContext *context;
OFPair OF_GENERIC(OFDate *, OFDNSResponse *) *cacheEntry;
[self of_cleanUpCache];
if ((cacheEntry = [_cache objectForKey: query]) != nil) {
uint32_t age =
(uint32_t)-[cacheEntry.firstObject timeIntervalSinceNow];
OFDNSResponse *response = cacheEntry.secondObject;
if (!containsExpiredRecord(response.answerRecords, age) &&
!containsExpiredRecord(response.authorityRecords, age) &&
!containsExpiredRecord(response.additionalRecords, age)) {
OFTimer *timer = [OFTimer
timerWithTimeInterval: 0
target: delegate
selector: @selector(resolver:
didPerformQuery:response:
exception:)
object: self
object: query
object: response
object: nil
repeats: false];
[[OFRunLoop currentRunLoop] addTimer: timer
forMode: runLoopMode];
objc_autoreleasePoolPop(pool);
return;
}
}
/* Random, unused ID */
do {
ID = [OFNumber numberWithUnsignedShort: OFRandom16()];
} while ([_queries objectForKey: ID] != nil);
if (query.domainName.UTF8StringLength > 253)
@throw [OFOutOfRangeException exception];
if (_settings->_nameServers.count == 0) {
id exception = [OFDNSQueryFailedException
exceptionWithQuery: query
errorCode: OFDNSResolverErrorCodeNoNameServer];
[delegate resolver: self
didPerformQuery: query
response: nil
exception: exception];
return;
}
context = [[[OFDNSResolverContext alloc]
initWithQuery: query
ID: ID
settings: _settings
delegate: delegate] autorelease];
[self of_sendQueryForContext: context runLoopMode: runLoopMode];
objc_autoreleasePoolPop(pool);
}
- (void)of_contextTimedOut: (OFDNSResolverContext *)context
{
OFRunLoopMode runLoopMode = [OFRunLoop currentRunLoop].currentMode;
OFDNSQueryFailedException *exception;
if (context->_TCPSocket != nil) {
context->_TCPSocket.delegate = nil;
[context->_TCPSocket cancelAsyncRequests];
[_TCPQueries removeObjectForKey: context->_TCPSocket];
[context->_TCPSocket release];
context->_TCPSocket = nil;
context->_responseLength = 0;
}
if (context->_nameServersIndex + 1 <
context->_settings->_nameServers.count) {
context->_nameServersIndex++;
[self of_sendQueryForContext: context runLoopMode: runLoopMode];
return;
}
if (++context->_attempt < context->_settings->_maxAttempts) {
context->_nameServersIndex = 0;
[self of_sendQueryForContext: context runLoopMode: runLoopMode];
return;
}
context = [[context retain] autorelease];
[_queries removeObjectForKey: context->_ID];
/*
* Cancel any pending queries, to avoid a send being still pending and
* trying to access the query once it no longer exists.
*/
[_IPv4Socket cancelAsyncRequests];
[_IPv4Socket asyncReceiveIntoBuffer: _buffer length: bufferLength];
#ifdef OF_HAVE_IPV6
[_IPv6Socket cancelAsyncRequests];
[_IPv6Socket asyncReceiveIntoBuffer: _buffer length: bufferLength];
#endif
exception = [OFDNSQueryFailedException
exceptionWithQuery: context->_query
errorCode: OFDNSResolverErrorCodeTimeout];
[context->_delegate resolver: self
didPerformQuery: context->_query
response: nil
exception: exception];
}
- (bool)of_handleResponseBuffer: (unsigned char *)buffer
length: (size_t)length
sender: (const OFSocketAddress *)sender
{
OFDictionary *answerRecords = nil, *authorityRecords = nil;
OFDictionary *additionalRecords = nil;
OFDNSResponse *response = nil;
id exception = nil;
OFNumber *ID;
OFDNSResolverContext *context;
if (length < 2)
/* We can't get the ID to get the context. Ignore packet. */
return true;
ID = [OFNumber numberWithUnsignedShort: (buffer[0] << 8) | buffer[1]];
context = [[[_queries objectForKey: ID] retain] autorelease];
if (context == nil)
return true;
if (context->_TCPSocket != nil) {
if ([_TCPQueries objectForKey: context->_TCPSocket] != context)
return true;
} else if (sender == NULL ||
!OFSocketAddressEqual(sender, &context->_usedNameServer))
return true;
[context->_cancelTimer invalidate];
[context->_cancelTimer release];
context->_cancelTimer = nil;
[_queries removeObjectForKey: ID];
@try {
OFDNSResolverErrorCode errorCode = 0;
bool tryNextNameServer = false;
const unsigned char *queryDataBuffer;
size_t i;
uint16_t numQuestions, numAnswers, numAuthorityRecords;
uint16_t numAdditionalRecords;
if (length < 12)
@throw [OFTruncatedDataException exception];
if (context->_queryData.itemSize != 1 ||
context->_queryData.count < 12)
@throw [OFInvalidArgumentException exception];
queryDataBuffer = context->_queryData.items;
/* QR */
if ((buffer[2] & 0x80) == 0)
@throw [OFInvalidServerResponseException exception];
/* Opcode */
if ((buffer[2] & 0x78) != (queryDataBuffer[2] & 0x78))
@throw [OFInvalidServerResponseException exception];
/* TC */
if (buffer[2] & 0x02) {
OFRunLoopMode runLoopMode;
if (context->_settings->_forcesTCP)
@throw [OFTruncatedDataException exception];
context->_settings->_forcesTCP = true;
runLoopMode = [OFRunLoop currentRunLoop].currentMode;
[self of_sendQueryForContext: context
runLoopMode: runLoopMode];
return false;
}
/* RCODE */
switch (buffer[3] & 0x0F) {
case 0:
break;
case 1:
errorCode = OFDNSResolverErrorCodeServerInvalidFormat;
break;
case 2:
errorCode = OFDNSResolverErrorCodeServerFailure;
tryNextNameServer = true;
break;
case 3:
errorCode = OFDNSResolverErrorCodeServerNameError;
break;
case 4:
errorCode = OFDNSResolverErrorCodeServerNotImplemented;
tryNextNameServer = true;
break;
case 5:
errorCode = OFDNSResolverErrorCodeServerRefused;
tryNextNameServer = true;
break;
default:
errorCode = OFDNSResolverErrorCodeUnknown;
tryNextNameServer = true;
break;
}
if (tryNextNameServer) {
if (context->_nameServersIndex + 1 <
context->_settings->_nameServers.count) {
OFRunLoopMode runLoopMode =
[OFRunLoop currentRunLoop].currentMode;
context->_nameServersIndex++;
[self of_sendQueryForContext: context
runLoopMode: runLoopMode];
return false;
}
}
if (buffer[3] & 0x0F)
@throw [OFDNSQueryFailedException
exceptionWithQuery: context->_query
errorCode: errorCode];
numQuestions = (buffer[4] << 8) | buffer[5];
numAnswers = (buffer[6] << 8) | buffer[7];
numAuthorityRecords = (buffer[8] << 8) | buffer[9];
numAdditionalRecords = (buffer[10] << 8) | buffer[11];
i = 12;
/*
* Skip over the questions - we use the ID to identify the
* query.
*
* TODO: Compare to our query, just in case?
*/
for (uint_fast16_t j = 0; j < numQuestions; j++) {
parseName(buffer, length, &i, maxAllowedPointers);
i += 4;
}
answerRecords = parseSection(buffer, length, &i, numAnswers);
authorityRecords = parseSection(buffer, length, &i,
numAuthorityRecords);
additionalRecords = parseSection(buffer, length, &i,
numAdditionalRecords);
response = [OFDNSResponse
responseWithDomainName: context->_query.domainName
answerRecords: answerRecords
authorityRecords: authorityRecords
additionalRecords: additionalRecords];
} @catch (id e) {
exception = e;
}
if (exception != nil)
response = nil;
[self of_cleanUpCache];
if (response != nil)
[_cache setObject: [OFPair pairWithFirstObject: [OFDate date]
secondObject: response]
forKey: context->_query];
else
[_cache removeObjectForKey: context->_query];
[context->_delegate resolver: self
didPerformQuery: context->_query
response: response
exception: exception];
return false;
}
- (bool)socket: (OFDatagramSocket *)sock
didReceiveIntoBuffer: (void *)buffer
length: (size_t)length
sender: (const OFSocketAddress *)sender
exception: (id)exception
{
if (exception != nil)
return true;
return [self of_handleResponseBuffer: buffer
length: length
sender: sender];
}
- (void)socket: (OFTCPSocket *)sock
didConnectToHost: (OFString *)host
port: (uint16_t)port
exception: (id)exception
{
OFDNSResolverContext *context = [_TCPQueries objectForKey: sock];
OFEnsure(context != nil);
if (exception != nil) {
/*
* TODO: Handle error immediately instead of waiting for the
* timer to try the next nameserver or to retry.
*/
[_TCPQueries removeObjectForKey: context->_TCPSocket];
[context->_TCPSocket release];
context->_TCPSocket = nil;
context->_responseLength = 0;
return;
}
if (context->_TCPQueryData == nil) {
size_t queryDataCount = context->_queryData.count;
uint16_t tmp;
if (queryDataCount > UINT16_MAX)
@throw [OFOutOfRangeException exception];
context->_TCPQueryData = [[OFMutableData alloc]
initWithCapacity: queryDataCount + 2];
tmp = OFToBigEndian16(queryDataCount);
[context->_TCPQueryData addItems: &tmp count: sizeof(tmp)];
[context->_TCPQueryData addItems: context->_queryData.items
count: queryDataCount];
}
[sock asyncWriteData: context->_TCPQueryData];
}
- (OFData *)stream: (OFStream *)stream
didWriteData: (OFData *)data
bytesWritten: (size_t)bytesWritten
exception: (id)exception
{
OFTCPSocket *sock = (OFTCPSocket *)stream;
OFDNSResolverContext *context = [_TCPQueries objectForKey: sock];
OFEnsure(context != nil);
if (exception != nil) {
/*
* TODO: Handle error immediately instead of waiting for the
* timer to try the next nameserver or to retry.
*/
[_TCPQueries removeObjectForKey: context->_TCPSocket];
[context->_TCPSocket release];
context->_TCPSocket = nil;
context->_responseLength = 0;
return nil;
}
if (context->_TCPBuffer == nil)
context->_TCPBuffer = OFAllocMemory(maxDNSResponseLength, 1);
[sock asyncReadIntoBuffer: context->_TCPBuffer exactLength: 2];
return nil;
}
- (bool)stream: (OFStream *)stream
didReadIntoBuffer: (void *)buffer
length: (size_t)length
exception: (id)exception
{
OFTCPSocket *sock = (OFTCPSocket *)stream;
OFDNSResolverContext *context = [_TCPQueries objectForKey: sock];
OFEnsure(context != nil);
if (exception != nil) {
/*
* TODO: Handle error immediately instead of waiting for the
* timer to try the next nameserver or to retry.
*/
goto done;
}
if (context->_responseLength == 0) {
unsigned char *ucBuffer = buffer;
OFEnsure(length == 2);
context->_responseLength = (ucBuffer[0] << 8) | ucBuffer[1];
if (context->_responseLength > maxDNSResponseLength)
@throw [OFOutOfRangeException exception];
if (context->_responseLength == 0)
goto done;
[sock asyncReadIntoBuffer: context->_TCPBuffer
exactLength: context->_responseLength];
return false;
}
if (length != context->_responseLength)
/*
* The connection was closed before we received the entire
* response.
*/
goto done;
[self of_handleResponseBuffer: buffer length: length sender: NULL];
done:
[_TCPQueries removeObjectForKey: context->_TCPSocket];
[context->_TCPSocket release];
context->_TCPSocket = nil;
context->_responseLength = 0;
return false;
}
- (void)asyncResolveAddressesForHost: (OFString *)host
delegate: (id <OFDNSResolverHostDelegate>)delegate
{
[self asyncResolveAddressesForHost: host
addressFamily: OFSocketAddressFamilyAny
runLoopMode: OFDefaultRunLoopMode
delegate: delegate];
}
- (void)asyncResolveAddressesForHost: (OFString *)host
addressFamily: (OFSocketAddressFamily)addressFamily
delegate: (id <OFDNSResolverHostDelegate>)delegate
{
[self asyncResolveAddressesForHost: host
addressFamily: addressFamily
runLoopMode: OFDefaultRunLoopMode
delegate: delegate];
}
- (void)asyncResolveAddressesForHost: (OFString *)host
addressFamily: (OFSocketAddressFamily)addressFamily
runLoopMode: (OFRunLoopMode)runLoopMode
delegate: (id <OFDNSResolverHostDelegate>)delegate
{
void *pool = objc_autoreleasePoolPush();
OFHostAddressResolver *resolver = [[[OFHostAddressResolver alloc]
initWithHost: host
addressFamily: addressFamily
resolver: self
settings: _settings
runLoopMode: runLoopMode
delegate: delegate] autorelease];
[resolver asyncResolve];
objc_autoreleasePoolPop(pool);
}
- (OFData *)resolveAddressesForHost: (OFString *)host
addressFamily: (OFSocketAddressFamily)addressFamily
{
void *pool = objc_autoreleasePoolPush();
OFHostAddressResolver *resolver = [[[OFHostAddressResolver alloc]
initWithHost: host
addressFamily: addressFamily
resolver: self
settings: _settings
runLoopMode: nil
delegate: nil] autorelease];
OFData *addresses = [resolver resolve];
[addresses retain];
objc_autoreleasePoolPop(pool);
return [addresses autorelease];
}
- (void)close
{
void *pool = objc_autoreleasePoolPush();
OFEnumerator OF_GENERIC(OFDNSResolverContext *) *enumerator;
OFDNSResolverContext *context;
[_IPv4Socket cancelAsyncRequests];
[_IPv4Socket release];
_IPv4Socket = nil;
#ifdef OF_HAVE_IPV6
[_IPv6Socket cancelAsyncRequests];
[_IPv6Socket release];
_IPv6Socket = nil;
#endif
enumerator = [_queries objectEnumerator];
while ((context = [enumerator nextObject]) != nil) {
OFDNSQueryFailedException *exception;
exception = [OFDNSQueryFailedException
exceptionWithQuery: context->_query
errorCode: OFDNSResolverErrorCodeCanceled];
[context->_delegate resolver: self
didPerformQuery: context->_query
response: nil
exception: exception];
}
[_queries removeAllObjects];
objc_autoreleasePoolPop(pool);
}
@end