Unix Programming - Re: Parsing Packets

Author

Re: Parsing Packets

chris

2004-06-30, 6:02 pm

Lev Walkin wrote:
> chris wrote:
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> u_char ip_p; /* protocol */
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> You're trying to perform byte swap on a single character.
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> Do not use ntohs() function, and you'll probably be fine.
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>

I removed the call to ntohs() but it didn't make a difference. I learned
that the BPF returns link layer headers (in this case ethernet) so I
tried to accomodate for them but it doesn't seem to make a difference

int
processPacket(char *packet, int size)
{
struct ip *iphdr;

iphdr = (struct ip *) packet + sizeof(struct ether_header);

printf("%x packet captured; %d bytes\n", iphdr->ip_p, size);
return 0;
}