ObjFW  Check-in [452616df69]

#import "OFCharacterSet.h"
#import "OFData.h"
#import "OFDictionary.h"
#import "OFFile.h"
#import "OFLocale.h"
#import "OFNumber.h"
#import "OFString.h"
#import "OFTimer.h"
#import "OFUDPSocket.h"
#ifdef OF_WINDOWS
# import "OFWindowsRegistryKey.h"
#endif

#import "OFInvalidArgumentException.h"
#import "OFInvalidServerReplyException.h"

 * 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.
 */
#define MAX_ALLOWED_POINTERS 16

#define TIMEOUT 2

/*
 * TODO:
 *

 *  - Resolve with each search domain
 *  - Iterate through name servers
 *  - Fallback to TCP
 */

@interface OFDNSResolver_context: OFObject
{
	OFString *_host;
	of_dns_resource_record_class_t _recordClass;
	of_dns_resource_record_type_t _recordType;
	OFNumber *_ID;
	OFArray OF_GENERIC(OFString *) *_nameServers, *_searchDomains;
	size_t _nameServersIndex, _searchDomainsIndex;
	OFMutableData *_queryData;
	id _target;
	SEL _selector;
	id _userContext;
	OFTimer *_timer;
}

@property (readonly, nonatomic) OFString *host;
@property (readonly, nonatomic) of_dns_resource_record_class_t recordClass;
@property (readonly, nonatomic) of_dns_resource_record_type_t recordType;
@property (readonly, nonatomic) OFNumber *ID;
@property (readonly, nonatomic) OFArray OF_GENERIC(OFString *) *nameServers;
@property (readonly, nonatomic) OFArray OF_GENERIC(OFString *) *searchDomains;
@property (nonatomic) size_t nameServersIndex;
@property (nonatomic) size_t searchDomainsIndex;
@property (readonly, nonatomic) OFMutableData *queryData;
@property (readonly, nonatomic) id target;
@property (readonly, nonatomic) SEL selector;
@property (readonly, nonatomic) id userContext;
@property (readonly, nonatomic) OFTimer *timer;

- (instancetype)initWithHost: (OFString *)host
		 recordClass: (of_dns_resource_record_class_t)recordClass
		  recordType: (of_dns_resource_record_type_t)recordType
			  ID: (OFNumber *)ID
		 nameServers: (OFArray OF_GENERIC(OFString *) *)nameServers
	       searchDomains: (OFArray OF_GENERIC(OFString *) *)searchDomains
		   queryData: (OFMutableData *)queryData
		      target: (id)target
		    selector: (SEL)selector
		 userContext: (id)userContext
		       timer: (OFTimer *)timer;
@end

@interface OFDNSResolver ()
#ifdef OF_HAVE_FILES
- (void)of_parseHosts: (OFString *)path;
# ifndef OF_WINDOWS
- (void)of_parseResolvConf: (OFString *)path;

@implementation OFDNSResolver_context
@synthesize host = _host, recordClass = _recordClass, recordType = _recordType;
@synthesize ID = _ID, nameServers = _nameServers;
@synthesize searchDomains = _searchDomains;
@synthesize nameServersIndex = _nameServersIndex;
@synthesize searchDomainsIndex = _searchDomainsIndex, queryData = _queryData;
@synthesize target = _target, selector = _selector, userContext = _userContext;
@synthesize timer = _timer;

- (instancetype)initWithHost: (OFString *)host
		 recordClass: (of_dns_resource_record_class_t)recordClass
		  recordType: (of_dns_resource_record_type_t)recordType
			  ID: (OFNumber *)ID
		 nameServers: (OFArray OF_GENERIC(OFString *) *)nameServers
	       searchDomains: (OFArray OF_GENERIC(OFString *) *)searchDomains
		   queryData: (OFMutableData *)queryData
		      target: (id)target
		    selector: (SEL)selector
		 userContext: (id)userContext
		       timer: (OFTimer *)timer
{
	self = [super init];

	@try {
		_host = [host copy];
		_recordClass = recordClass;
		_recordType = recordType;
		_ID = [ID retain];
		_nameServers = [nameServers copy];
		_searchDomains = [searchDomains copy];
		_queryData = [queryData retain];
		_target = [target retain];
		_selector = selector;
		_userContext = [userContext retain];
		_timer = [timer retain];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[_host release];
	[_ID release];
	[_nameServers release];
	[_searchDomains release];
	[_queryData release];
	[_target release];
	[_userContext release];
	[_timer release];

	[super dealloc];
}
@end

@implementation OFDNSResolver
@synthesize staticHosts = _staticHosts, nameServers = _nameServers;

	ID = [OFNumber numberWithUInt16: (buffer[0] << 8) | buffer[1]];
	DNSResolverContext = [[[_queries objectForKey: ID] retain] autorelease];

	if (DNSResolverContext == nil)
		return false;

	[[DNSResolverContext timer] invalidate];
	[_queries removeObjectForKey: ID];

	target = [DNSResolverContext target];
	selector = [DNSResolverContext selector];
	callback = (void (*)(id, SEL, OFArray *, id, id))
	    [target methodForSelector: selector];
	queryData = [DNSResolverContext queryData];

	}

	callback(target, selector, answers, [DNSResolverContext userContext],
	    nil);

	return false;
}

- (void)of_queryWithIDTimedOut: (OFNumber *)ID
{
	OFDNSResolver_context *DNSResolverContext = [_queries objectForKey: ID];
	id target;
	SEL selector;
	void (*callback)(id, SEL, OFArray *, id, id);
	OFResolveHostFailedException *exception;

	if (DNSResolverContext == nil)
		return;

	target = [[[DNSResolverContext target] retain] autorelease];
	selector = [DNSResolverContext selector];
	callback = (void (*)(id, SEL, OFArray *, id, id))
	    [target methodForSelector: selector];

	exception = [OFResolveHostFailedException
	    exceptionWithHost: [DNSResolverContext host]
		  recordClass: [DNSResolverContext recordClass]
		   recordType: [DNSResolverContext recordType]
			error: OF_DNS_RESOLVER_ERROR_TIMEOUT];

	[_queries removeObjectForKey: [DNSResolverContext ID]];

	callback(target, selector, nil,
	    [DNSResolverContext userContext], exception);
}

- (size_t)of_socket: (OFUDPSocket *)sock
      didSendBuffer: (void **)buffer
	  bytesSent: (size_t)bytesSent
	   receiver: (of_socket_address_t *)receiver
	    context: (id)DNSResolverContext
	  exception: (id)exception

	      recordType: (of_dns_resource_record_type_t)recordType
		  target: (id)target
		selector: (SEL)selector
		 context: (id)context
{
	void *pool = objc_autoreleasePoolPush();
	OFMutableData *data = [OFMutableData dataWithCapacity: 512];
	OFTimer *timer;
	OFDNSResolver_context *DNSResolverContext;
	OFNumber *ID;
	uint16_t tmp;
	OFUDPSocket *sock;
	of_socket_address_t address;

	/* TODO: Properly try all search domains */

		 count: 2];

	/* QCLASS */
	tmp = OF_BSWAP16_IF_LE(recordClass);
	[data addItems: &tmp
		 count: 2];

	timer = [OFTimer
	    scheduledTimerWithTimeInterval: TIMEOUT
				    target: self
				  selector: @selector(of_queryWithIDTimedOut:)
				    object: ID
				   repeats: false];

	DNSResolverContext = [[[OFDNSResolver_context alloc]
	    initWithHost: host
	     recordClass: recordClass
	      recordType: recordType
		      ID: ID
	     nameServers: _nameServers
	   searchDomains: _searchDomains
	       queryData: data
		  target: target
		selector: selector
	     userContext: context
		   timer: timer] autorelease];
	[_queries setObject: DNSResolverContext
		     forKey: ID];

	address = of_socket_address_parse_ip(
	    [[DNSResolverContext nameServers] firstObject], 53);

#ifdef OF_HAVE_IPV6