Re: [lwip-users] Pulling data from a server using HTTP with lwIP

[Simon Goldschmidt]

Robert Wood wrote:
> Sorry, I'm obviously still not explaining this clearly.

I don't really think that this is our problem...


To get a grip on this, could you please explain your pcaps:

- which IP is lwIP, which IP is the remote host in question (there are plenty 
of hosts in your pcap file, not only 2!)
- which packet numbers are you talking about?
- which packet number exactly is the one you wouldn't expect, or in other 
words, where would the missing ACK be inserted?

I can again try to explain why *I* think that packet #54 in 
"no_ack_but_get.pcap" is correct: I think you are expecting an ACK packet here 
(note that an [ACK] packet is only a description of wireshark: in TCP, this is 
a packet with the ACK flag set but no user data contained).

Instead of this packet (ACK but no data) you get the "GET" request, which in 
TCP is ACK+DATA. This is perfectly valid to me.

Maybe you should tell us what the real problem is. I think your real problem is 
the missing HTTP answer. So why not start and send a correct HTTP request? Like 
Mikale Eiman wrote, "GET /index.html HTTP/1.0\r\n\r\n" (double newline at the 
end) should be enough when the send length is correct (you seem to be sending 
invalid data after the HTTP header!).


Hope that helps,
Simon