ProgrammingThis forum is for all programming questions.
The question does not have to be directly related to Linux and any language is fair game.
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
I have written a kernel module that accesses skbuff and depending on whether packet is icmp or not it prints IP checksum and ICMP checksum. But I am getting
sum.c: In function `hook_func1':
sum.c:24: dereferencing pointer to incomplete type
sum.c: In function `hook_func2':
sum.c:40: dereferencing pointer to incomplete type
I am just wondering about how header files are added to other header files and source files.
Say if i added following statement in dev.c
printk(KERN_DEBUG "TCP cksum=%d",skb->h.th->check);
This works without pointer dereference.
But same is not true with
printk(KERN_DEBUG "UCP cksum=%d",skb->h.uh->check);
This gives pointer dereference error.
That mean some header file may be already added tcp.h
Now if we see skbuff.h there are no network protocol headers are defined why?
Isn't that a very important socket buffer structure? In compilation it does not give error for including tcp.h,ip.h,icmp.h...
then how those network headers are added to skbuff.h?