How to get tcp/udp opening port list on iphone by objective-c?

Question

Hi I want to get all tcp/udp opening port status list on iphone by objective-c? like netstat on Linux, Do you know how to achieve it or it there any API　can do that? Thanks.

Answer 1

You can't run netstat on an iPhone (unless you jailbreak it), but you can do what netstat does. Take a look at function protopr in the netstat source code. I verified that you can call sysctlbyname with "net.inet.tcp.pcblist" as the name and get back a bunch of data. I didn't try to interpret the data like netstat does.

Test case:

size_t len = 0;
if (sysctlbyname("net.inet.tcp.pcblist", 0, &len, 0, 0) < 0) {
    perror("sysctlbyname");
} else {
    char *buf = malloc(len);
    sysctlbyname("net.inet.tcp.pcblist", buf, &len, 0, 0);
    NSData *data = [NSData dataWithBytesNoCopy:buf length:len];
    NSLog(@"data = %@", data);
}

Output on my iPad 2 running iOS 5.0:

2011-11-17 19:59:34.712 keyboardtest[29423:707] data = <18000000 2c000000 9e2a0900
00000000 c60e5d00 00000000 0c020000 00000000 00000000 00000000 00000000 d4d3d4d2
00000000 00000000 ...

and lots more I have truncated.

Make sure you're initializing len to 0. Also, you can't just put the contents of buf in an NSString as if it were a C string. It's not. It's binary data that you have to interpret, like netstat does.

Presumably you want to interpret the data. You need to read through the protopr function in the netstat source code, which I linked to above. The data structures used by protopr are declared in <netinet/in_pcb.h>, <netinet/tcp_var.h>, and other header files in /usr/include/netinet. These header files are included in the iOS SDK (as of iOS 7.0 at least), so you can use them.

Answer 2

To get the data obtained by the rob mayoff's answer readable you just need to take a look at the code of inet.c. In it, you have all you need to parse the data.

Take a look at my another answer in the question of Hisenberg: Network Activity Monitoring on iPhone

In my code, you can see in what part of the code the data is readable, that is when I add the values to the dictionary.