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Hello,
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
Whats wrong?
regards,
cranium.
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?
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