Retired Document
Important: This sample code may not represent best practices for current development. The project may use deprecated symbols and illustrate technologies and techniques that are no longer recommended.
PortMapper.m
/* |
File: PortMapper.m |
Abstract: Objective-C class implementation using Bonjour port mapping |
Version: 1.0 |
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*/ |
#import "PortMapper.h" |
#import <dns_sd.h> |
#import <sys/types.h> |
#import <sys/socket.h> |
#import <net/if.h> |
#import <netinet/in.h> |
#import <ifaddrs.h> |
#ifndef Log |
#define ENABLE_LOGGING 0 /* Change value to 1 to enable logging. */ |
#define Log if(!ENABLE_LOGGING) ; else NSLog |
#endif |
NSString* const PortMapperChangedNotification = @"PortMapperChanged"; |
/** Converts a raw IPv4 address to an NSString in dotted-quad notation */ |
static NSString* StringFromIPv4Addr( UInt32 ipv4Addr ) |
{ |
if( ipv4Addr != 0 ) { |
const UInt8* addrBytes = (const UInt8*)&ipv4Addr; |
return [NSString stringWithFormat: @"%u.%u.%u.%u", |
(unsigned)addrBytes[0],(unsigned)addrBytes[1], |
(unsigned)addrBytes[2],(unsigned)addrBytes[3]]; |
} else |
return nil; |
} |
@interface PortMapper () |
// Redeclare these properties as settable, internally: |
@property (readwrite) SInt32 error; |
@property (readwrite) UInt32 rawPublicAddress; |
@property (copy) NSString* publicAddress; |
@property (readwrite) unsigned short publicPort; |
// Private getter: |
@property (readonly) void* _service; |
- (void) priv_disconnect; |
@end |
@implementation PortMapper |
- (id) initWithPort: (UInt16)port |
{ |
self = [super init]; |
if (self != nil) { |
_port = port; |
_mapTCP = YES; |
} |
return self; |
} |
- (void) dealloc |
{ |
if( _service ) |
[self priv_disconnect]; |
[super dealloc]; |
} |
- (void) finalize |
{ |
if( _service ) |
[self priv_disconnect]; |
[super finalize]; |
} |
@synthesize publicAddress=_publicAddress, rawPublicAddress=_rawPublicAddress, |
publicPort=_publicPort, error=_error, _service=_service, |
mapTCP=_mapTCP, mapUDP=_mapUDP, |
desiredPublicPort=_desiredPublicPort; |
- (BOOL) isMapped |
{ |
return _rawPublicAddress && _rawPublicAddress != [[self class] rawLocalAddress]; |
} |
/** Called whenever the port mapping changes (see comment for callback, below.) */ |
- (void) priv_portMapStatus: (DNSServiceErrorType)errorCode |
publicAddress: (UInt32)rawPublicAddress |
publicPort: (UInt16)publicPort |
{ |
if( errorCode ) { |
Log(@"Port-mapping callback got error %i",errorCode); |
} else { |
if( publicPort == 0 && _desiredPublicPort != 0 ) { |
Log(@"Port-mapping callback reported no mapping available"); |
errorCode = kDNSServiceErr_NATPortMappingUnsupported; |
} |
} |
if( errorCode != self.error ) |
self.error = errorCode; |
if( rawPublicAddress != self.rawPublicAddress ) { |
self.rawPublicAddress = rawPublicAddress; |
self.publicAddress = StringFromIPv4Addr(rawPublicAddress); |
} |
if( publicPort != self.publicPort ) |
self.publicPort = publicPort; |
if( ! errorCode ) { |
Log(@"PortMapper: Got %@ :%hu (mapped=%i)", self.publicAddress,self.publicPort,self.isMapped); |
} |
[[NSNotificationCenter defaultCenter] postNotificationName: PortMapperChangedNotification |
object: self]; |
} |
/** Asynchronous callback from DNSServiceNATPortMappingCreate. |
This is invoked whenever the status of the port mapping changes. |
All it does is dispatch to the object's priv_portMapStatus:publicAddress:publicPort: method. */ |
static void portMapCallback ( |
DNSServiceRef sdRef, |
DNSServiceFlags flags, |
uint32_t interfaceIndex, |
DNSServiceErrorType errorCode, |
uint32_t publicAddress, /* four byte IPv4 address in network byte order */ |
DNSServiceProtocol protocol, |
uint16_t privatePort, |
uint16_t publicPort, /* may be different than the requested port */ |
uint32_t ttl, /* may be different than the requested ttl */ |
void *context |
) |
{ |
NSAutoreleasePool *pool = [NSAutoreleasePool new]; |
@try{ |
[(PortMapper*)context priv_portMapStatus: errorCode |
publicAddress: publicAddress |
publicPort: ntohs(publicPort)]; // port #s in network byte order! |
}@catch( id x ) { |
NSLog(@"PortMapper caught exception: %@",x); |
} |
[pool drain]; |
} |
/** CFSocket callback, informing us that _socket has data available, which means |
that the DNS service has an incoming result to be processed. This will end up invoking |
the portMapCallback. */ |
static void serviceCallback(CFSocketRef s, |
CFSocketCallBackType type, |
CFDataRef address, const void *data, void *clientCallBackInfo) |
{ |
PortMapper *mapper = (PortMapper*)clientCallBackInfo; |
DNSServiceRef service = mapper._service; |
DNSServiceErrorType err = DNSServiceProcessResult(service); |
if( err ) { |
// An error here means the socket has failed and should be closed. |
[mapper priv_portMapStatus: err publicAddress: 0 publicPort: 0]; |
[mapper priv_disconnect]; |
} |
} |
- (BOOL) open |
{ |
NSAssert(!_service,@"Already open"); |
// Create the DNSService: |
DNSServiceProtocol protocol = 0; |
if( _mapTCP ) protocol |= kDNSServiceProtocol_TCP; |
if( _mapUDP ) protocol |= kDNSServiceProtocol_UDP; |
self.error = DNSServiceNATPortMappingCreate((DNSServiceRef*)&_service, |
0 /*flags*/, |
0 /*interfaceIndex*/, |
protocol, |
htons(_port), |
htons(_desiredPublicPort), |
0 /*ttl*/, |
&portMapCallback, |
self); |
if( _error ) { |
Log(@"Error %i creating port mapping",_error); |
return NO; |
} |
// Wrap a CFSocket around the service's socket: |
CFSocketContext ctxt = { 0, self, CFRetain, CFRelease, NULL }; |
_socket = CFSocketCreateWithNative(NULL, |
DNSServiceRefSockFD(_service), |
kCFSocketReadCallBack, |
&serviceCallback, &ctxt); |
if( _socket ) { |
CFSocketSetSocketFlags(_socket, CFSocketGetSocketFlags(_socket) & ~kCFSocketCloseOnInvalidate); |
// Attach the socket to the runloop so the serviceCallback will be invoked: |
_socketSource = CFSocketCreateRunLoopSource(NULL, _socket, 0); |
if( _socketSource ) |
CFRunLoopAddSource(CFRunLoopGetCurrent(), _socketSource, kCFRunLoopCommonModes); |
} |
if( _socketSource ) { |
Log(@"Opening PortMapper"); |
return YES; |
} else { |
Log(@"Failed to open PortMapper"); |
[self close]; |
_error = kDNSServiceErr_Unknown; |
return NO; |
} |
} |
- (BOOL) waitTillOpened |
{ |
if( ! _socketSource ) |
if( ! [self open] ) |
return NO; |
// Run the runloop until there's either an error or a result: |
while( _error==0 && _publicAddress==nil ) |
if( ! [[NSRunLoop currentRunLoop] runMode: NSDefaultRunLoopMode |
beforeDate: [NSDate distantFuture]] ) |
break; |
return (_error==0); |
} |
// Close down, but _without_ clearing the 'error' property |
- (void) priv_disconnect |
{ |
if( _socketSource ) { |
CFRunLoopSourceInvalidate(_socketSource); |
CFRelease(_socketSource); |
_socketSource = NULL; |
} |
if( _socket ) { |
CFSocketInvalidate(_socket); |
CFRelease(_socket); |
_socket = NULL; |
} |
if( _service ) { |
Log(@"Deleting port mapping"); |
DNSServiceRefDeallocate(_service); |
_service = NULL; |
self.rawPublicAddress = 0; |
self.publicAddress = nil; |
self.publicPort = 0; |
} |
} |
- (void) close |
{ |
[self priv_disconnect]; |
self.error = 0; |
} |
#pragma mark - |
#pragma mark UTILITY CLASS METHODS: |
+ (UInt32) rawLocalAddress |
{ |
// getifaddrs returns a linked list of interface entries; |
// find the first active non-loopback interface with IPv4: |
UInt32 address = 0; |
struct ifaddrs *interfaces; |
if( getifaddrs(&interfaces) == 0 ) { |
struct ifaddrs *interface; |
for( interface=interfaces; interface; interface=interface->ifa_next ) { |
if( (interface->ifa_flags & IFF_UP) && ! (interface->ifa_flags & IFF_LOOPBACK) ) { |
const struct sockaddr_in *addr = (const struct sockaddr_in*) interface->ifa_addr; |
if( addr && addr->sin_family==AF_INET ) { |
address = addr->sin_addr.s_addr; |
break; |
} |
} |
} |
freeifaddrs(interfaces); |
} |
return address; |
} |
+ (NSString*) localAddress |
{ |
return StringFromIPv4Addr( [self rawLocalAddress] ); |
} |
// Private IP address ranges. See RFC 3330. |
static const struct {UInt32 mask, value;} const kPrivateRanges[] = { |
{0xFF000000, 0x00000000}, // 0.x.x.x (hosts on "this" network) |
{0xFF000000, 0x0A000000}, // 10.x.x.x (private address range) |
{0xFF000000, 0x7F000000}, // 127.x.x.x (loopback) |
{0xFFFF0000, 0xA9FE0000}, // 169.254.x.x (link-local self-configured addresses) |
{0xFFF00000, 0xAC100000}, // 172.(16-31).x.x (private address range) |
{0xFFFF0000, 0xC0A80000}, // 192.168.x.x (private address range) |
{0,0} |
}; |
+ (BOOL) localAddressIsPrivate |
{ |
UInt32 address = ntohl([self rawLocalAddress]); |
int i; |
for( i=0; kPrivateRanges[i].mask; i++ ) |
if( (address & kPrivateRanges[i].mask) == kPrivateRanges[i].value ) |
return YES; |
return NO; |
} |
+ (NSString*) findPublicAddress |
{ |
// To find our public IP address, open a PortMapper with no port or protocols. |
// This will cause the DNSService to look up our public address without creating a mapping. |
NSString *addr = nil; |
PortMapper *mapper = [[self alloc] initWithPort: 0]; |
mapper.mapTCP = mapper.mapUDP = NO; |
if( [mapper waitTillOpened] ) |
addr = mapper.publicAddress; |
[mapper close]; |
[mapper release]; |
return addr; |
} |
@end |
Copyright © 2008 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2008-07-25