[net2-wg] Good result (very slow test)

[Rodrigo Fonseca]

Hi,

I think the two fixes to the code are :

1. From Phil's second email:
(in Send.send()):

    call Packet.setPayloadLength(msg, len + sizeof(network_header_t));

should become

    call Packet.setPayloadLength(msg, len);

This seems to be correct, since setPayloadLength already adds the header size.

2. From Phil's first email re: code in ForwardingEngineP.forward()

The code is currently

   uint8_t len = call SubPacket.payloadLength(m);
      qe->msg = m;
      qe->client = 0xff;
   call Packet.setPayloadLength(m, len + sizeof(network_header_t));

I don't see the reason for this. Maybe I'm missing something.

len is read from SubPacket. It's the entire length.
The length of Packet is supposed to be that *minus* the network header.
Calling Packet.setPayloadLength has no effect other than setting the
length of the SubPacket to be the argument *plus* the header size.

If the SubPacket length was L, this code has the effect of making it
L+2*sizeof(network_header_t).

It should be only
...
      qe->msg = m;
      qe->client = 0xff;
...
This code assumes that SubPacket.payload is correct, and that
assumption is enough for everything else to work.

I will test this after the conference call.
Cheers,

Rodrigo



On 6/14/06, Philip Levis <pal at cs.stanford.edu> wrote:
> On Jun 14, 2006, at 7:07 PM, Sukun Kim wrote:
>
> > The packet is longer only when it's more than 1 hop.
>
> This is almost certainly a bug in ForwardingEngineP.forward(), then.
>
> The fact that the difference is 8 bytes is confusing. But I'll hazard
> a guess that these lines are at least part of the culprit:
>
>        uint8_t len = call SubPacket.payloadLength(m);
>
>        qe->msg = m;
>        qe->client = 0xff;
>
>        call Packet.setPayloadLength(m, len + sizeof(network_header_t));
>
> It's getting the sub length (which is the full packet length) and
> then adding a network_header_t. The code should either be
>
>        qe->msg = m;
>        qe->client = 0xff;
>
>        call Packet.setPayloadLength(m, call SubPacket.payloadLength(m));
>
> or
>
>        uint8_t len = call Packet.payloadLength(m);
>
>        qe->msg = m;
>        qe->client = 0xff;
>
>        call Packet.setPayloadLength(m, len + sizeof(network_header_t));
>
> (the former is probably better).
>
> You might even be able to cut out this code entirely. I'll need to
> think on that, though.
>
> Phil
>
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