On 12/07/16 11:40, Andrey Sverdlichenko wrote:
they both reading what other one sends to them? Given that your code only fails on large files, I guess sender never reads this 4-byte status messages receiver sends to it, and processes deadlock after socket buffer is filled up.
Right on the nail. I played a bit with tcpdump/wireshark to see I was just sending 0 length ACKs and multiple 4 byte messages joined on a single packet. Seems TCP buffers tiny packets using a strategy called Nagle's algorithm and thus joined all my packets on a bufferzone until a threeshold. Then it sent them all at once, making the other end crazy. Adding on a function that set-ups the socket this line newSocket :: AddrInfo -> IO Socket newSocket addr = do sock <- socket AF_INET Stream defaultProtocol setSocketOption sock NoDelay 1 -- this was added connect sock (addrAddress addr) return sock makes the downloads go until the end. :-)
As a side node, consider using putWord32be from binary or cereal packages instead of serializing data yourself.
Note taken. I just don't want to impose on a new dependency on my first patch. I did copy/pasted putWord32be (at least on style) for my int2BS function though. Thanks a lot! -- Ruben Astudillo