searching for a string in the data contents of a socket buffer

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Date: 18 Nov 2003 22:04:44 -0800

I'm trying to search for character stings in the payload of udp
packets inside a socket buffer (in the kernel before the socket buffer
has been copied to user space).

I'm doing this on an Intel machine. Intel uses little endian byte
order. The packets come across the network in big endian byte order.

If I start at the data head inside the skb and advance one byte at a
time will I see the bytes as they came across the network or will the
little endian byte order screw things up. i.e. is the payload stored
in the skb as 4 Byte words as such:

bytes as they come across the network:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ...

bytes in main memory (4 byte words in little endian byte order)

3, 2, 1, 0, 7, 6, 5 ,4

I'm searching for strings, so I need to see the bytes as they were
transmitted. If I want to inspect the packet contents one byte at a
time, can I just do this...

unsigned char *p_data = skb->data;
while (*pdata != 0x20) {
      do_stuff();
      pdata++;
}

or will advancing the pointer one byte at a time yield the wrong
order? i.e. 3, 2, 1, 0, 7, 6, 5, 4....

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