Question

Do you know any way to print in readable format an ipv6 address and its port from the inet_sock struct?
My question has two parts. One is which are the structure members that have this information and the second is how to print them in readable format.

Thanks!

Answer 1

printk has new modifiers which help printing inet addresses (I think since kernel 2.6.24). So you can try several ways, as an example:

//destination address
printk("%pI6 %d\n", my_inet_socket->pinet6->daddr, 
                    ntohs(my_inet_socket->inet_dport));
//source address
printk("%pI6 %d\n", my_inet_socket->pinet6->saddr, 
                    ntohs(my_inet_socket->inet_sport));

Here’s how many modifiers you have and how they print the IPv6 address. You can check http://www.kernel.org/doc/Documentation/printk-formats.txt for more info.

%pI6 0001:0002:0003:0004:0005:0006:0007:0008
%pi6 00010002000300040005000600070008
%pI6c 1:2:3:4:5:6:7:8

For older kernels you need to use NIP6 like this:

//destination address
printk(NIP6_FMT " %d\n", NIP6(my_inet_socket->pinet6->daddr), 
                         ntohs(my_inet_socket->inet_dport));
//source address
printk(NIP6_FMT " %d\n", NIP6(my_inet_socket->pinet6->saddr), 
                         ntohs(my_inet_socket->inet_sport));

As a last note, you can check net/ipv6/tcp_ipv6.c from the kernel itself. It has tons of examples. Hope this helps you