[lwip-users] [lwip] wrong type for "pcb->tmr" ?

[Jörg Kesten]

Hi all,

I think there is a bug in the definition of the pcb structure. The "tmr" 
member variable is defined as "u16_t", but upon creation of a new pcb in 
"tcp_new()" it is initialized with the current value of tcp_ticks, which 
is of type "u32_t".

The problem we encountered is this:
We connect to our device over a gsm-modem connection, i.e. "ping time" 
is 700-800 ms. Thus, after receiving a "SYN", tcp_slowtmr() is triggerd 
while the pcb is in state "SYN_RECV".

For the first 9h or so everything works fine, but when the value of 
"tcp_ticks" leaves the u16_t range, the value is truncated in
tcp_new(): pcb->tmr = tcp_ticks.
Then the check:
     if(pcb->state == SYN_RCVD) {
->      if((u32_t)(tcp_ticks - pcb->tmr) >
         TCP_SYN_RCVD_TIMEOUT / TCP_SLOW_INTERVAL) {
         ++pcb_remove;
       }
     }
in tcp_slowtmr() always is true and the pcb will be deleted before the 
connection can be established.

We changed the type of pcb->tmr to u32_t, and now everything seems to work.
The question is, is this the right fix, or has it to be done in a 
different way? Did we break something in another place?

CU
Joerg
-- 
email: address@hidden

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