How to get ip address from NetService

Question

When I get a NetService object，I try to do：

NSNetService *ss=[netArray objectAtIndex:indexPath.row];
ss.delegate=self;
[ss resolveWithTimeout:3.0];

On the delegate method：

-(void)netServiceDidResolveAddress:(NSNetService *)sender
{
   NSArray *address=sender.addresses;
   NSData *addressData=[NSData dataWithBytes:address length:sizeof(address)];
   /*
   How?
   */
}

Thanks.

Please mind that the method `NSNetService#address` returns multiple objects: `An array containing NSData objects, each of which contains a socket address for the service.` ([source](http://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Classes/NSNetService_Class/Reference/Reference.html)). Therefore you should iterate the array. — JJD, Sep 25 '12 at 09:09

score 7 · Answer 1 · answered Aug 25 '13 at 10:39

// Sent when addresses are resolved
- (void)netServiceDidResolveAddress:(NSNetService *)netService
{
    // Make sure [netService addresses] contains the
    // necessary connection information
    if ([self addressesComplete:[netService addresses]
                 forServiceType:[netService type]]) {
        [services addObject:netService];
    }
}

// Verifies [netService addresses]
- (BOOL)addressesComplete:(NSArray *)addresses
           forServiceType:(NSString *)serviceType
{

    // Perform appropriate logic to ensure that [netService addresses]
    // contains the appropriate information to connect to the service

    NSData *myData = nil;
    myData = [addresses objectAtIndex:0];

    NSString *addressString;
    int port=0;
    struct sockaddr *addressGeneric;
    struct sockaddr_in addressClient;


    addressGeneric = (struct sockaddr *) [myData bytes];

    switch( addressGeneric->sa_family ) {
        case AF_INET: {
            struct sockaddr_in *ip4;
            char dest[INET_ADDRSTRLEN];
            ip4 = (struct sockaddr_in *) [myData bytes];
            port = ntohs(ip4->sin_port);
            addressString = [NSString stringWithFormat: @"IP4: %s Port: %d", inet_ntop(AF_INET, &ip4->sin_addr, dest, sizeof dest),port];
        }
            break;

        case AF_INET6: {
            struct sockaddr_in6 *ip6;
            char dest[INET6_ADDRSTRLEN];
            ip6 = (struct sockaddr_in6 *) [myData bytes];
            port = ntohs(ip6->sin6_port);
            addressString = [NSString stringWithFormat: @"IP6: %s Port: %d",  inet_ntop(AF_INET6, &ip6->sin6_addr, dest, sizeof dest),port];
        }
            break;
        default:
            addressString=@"Unknown family";
            break;
    }

    NSLog(@"Client Address: %@",addressString);


    return YES;
}

This is the output Client Address: IP4: 192.168.69.38 Port: 58612

Why is serviceType here but unused? – TealShift Aug 01 '16 at 21:19 — TealShift, Aug 01 '16 at 21:19

JJD · Answer 2 · 2012-09-25T22:23:29.943

I found a post which suggests the following solution.

NSString* addressString = [[NSString alloc] initWithData:addressData encoding:NSASCIIStringEncoding];

Though it does not output a human readable string for me... It might work for you.

This is what is written to the console when I print the NSData object.

<10026a5e 0a0a7893 00000000 00000000>

Meanwhile, I found out that the second segment is the hexadecimal form of the ip-address. In this example it is ...

10.10.120.147 // 0a0a7893

I have written a Host class that does the conversion. The NSString extension can be found here. I only use the first 16-bytes address and ignore all others. Feel free to extend the class.

So please share your solution with everybody else. This is how this platform works. — JJD, Sep 26 '12 at 14:56

How to get ip address from NetService

2 Answers2

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