Thread: how to access structures of...

structures, is my question.

well i wanted to print out eveything that an icmp packet holds, like checksum, mtu and the id for example.

i included </linux/icmp.h>

Code:

struct icmphdr *icmp;

...
...

printf("checksum is: %d\n", icmp->checksum);

that works fine.
but in the /linux/icmp.h header file there is more than one structure like:

Code:

struct icmphdr {
  __u8 checksum;

   union {
        struct {
          __u16 id;
          } echo;
              } frag;

how would i print out the id of the icmp packet now?
the id code is included in the union frag and the struct echo as seen above.


thank you

didnt thought it would be that easy.