I don't understand why you're stripping off the outer mac and IP
headers. Why not just let the normal dissectors do their jobs of
calling the next dissector? Is there an IP protocol number which lets
the IP dissector know to pass the payload to the ethernet dissector?
--gilbert
On 8/30/05, Charles Wilkinson <c_s_wilkinson@xxxxxxxxxxx> wrote:
> Hi list, need some info on dissecting mac tunnels.
> Optical is a protocol that encapsulates ethernet
> frames in another ethernet frame with an IP header. so
> we have:
>
> MAC-IP-MAC-trailers. I've stripped off the outer mac
> and IP and am trying to call the ethernet disector to
> break up the innner mac frame. Here's the code
>
> static dissector_handle_t eth_handle;
> eth_handle = find_dissector("eth");
> int available_length = tvb_length(tvb) - 26;/*20 for
> the ip header and 6 for the TLS*/
> int reported_length = hlen - 26;
> next_tvb = tvb_new_subset(
> tvb,
> 26,
> MIN(available_length, reported_length),
> reported_length
> );
> call_dissector(eth_handle, next_tvb, pinfo,
> parent_tree);
> return;
>
> All I get is [malformed IP Packet] after the first two
> layers (i.e. the ouer MAc and IP) so it is calling the
> eth dissector and it doesn't crash but it isn't
> dissecting the inner ethernet and all the rest of the
> layers above it.
> Interesting problem, pls help.
> I have also a problem concerning display of non byte
> alligned data, the 6 bit post.
> Please help as this protocol is going to be widely
> used and dissection is important.
> All the best
> Charles
>
> contact: c_s_wilkinson@xxxxxxxxxxx
>
>
>
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