[lwip-users] Possible SNTP bug

[Bernhard 'Gustl' Bauer]

Hi,

I'm using lwip 1.3, NO_SYS. I know it is not up to date, but the contrib 
1.4 for sntp has not changed much since 1.3 and I checked the differences.

My problem is: the HEAP has an overflow when the time server could not 
be reached. The pbuf_alloc() in sntp_send_request() has no matching 
pbuf_free() in this case. The only pbuf_free() I found is in 
sntp_recv(), so pbuf can only be freed when there is an answer. 
sntp_send() is called repeatedly by sntp_retry().

Even when the time server can be reached there is a slight increase in 
used HEAP space. But this could be dropped packets which would have the 
same effect due to the above error.

I can think of 2 solutions: Use always the same pbuf, or free it during 
sntp_retry. Some pointers how to do this the right way would be great.

TIA

Gustl