Hello all, I'm writing an IRC client to which I'm adding SSL to the DCC chat & send file functions. Everything went peachy keen with SSLing DCC chat, but I ran into a minor problem adding SSL to send file.
Basically in DCC send file the sender sends 256 byte blocks of the file and the receiver acknowledges each block with 4 bytes of a long int saying total bytes of the file received so far. Originally the sender waited for each acknowledgement before sending the next block, but these days most IRC clients use the so-called "fast send" variant in which the sender doesn't wait for the acknowledgements. I enhanced my DCC send file code so that it could send blocks larger than 256 bytes in order to speed up the process. This works fine over an SSLed link up to 8192 byte block size. But at 8193 bytes and higher per block the SSL_write() on the sender's side eventually ends up returning -1 every time with SSL_get_error() returning SSL_ERROR_WANT_WRITE, thus send file stalls. On the receiver's end SSL_write() never returns an error. SSL_read() doesn't return an error on the receiver's side, either, but that's because I'm MSG_PEEK-ing at the socket to see if there is data available. I'm writing using VC++ on Win2Kpro with non-blocking sockets by way of the MFC class CAsyncSocket. When data is available on a socket CAsyncSocket::OnReceive() is called. My function then reads the socket until it is exhausted, the function exits and things go on until CAsyncSocket::OnReceive() is called again. My OpenSSL libs are openssl-0.9.7-stable-SNAP-20020831. I found it odd that everything would flow through just fine when writing blocks of 8192 bytes and smaller, but just one byte more would cause the SSL link to stall. And nor could I figure out why the error would be SSL_ERROR_WANT_WRITE. I made up a specific text file to test with - each line 64 bytes long (including the \r\n at the end) with number that increased every line so I could track how much data was actually getting through before the stall. The receiver gets every line in every block sent by the sender in all successful calls SSL_write(), sot it appears that as soon as SSL_write() returns -1 that not even part of the data is gets through. The sender also appears to receiver, with SSL_read() all the 4 byte acknowledgement blocks sent by the receiver. Is this an expected problem with SSL? I.e. it specifically can't handle writing blocks of larger than 8192 bytes at a time? Thanks in advance. __________________________________________________ Do you Yahoo!? New DSL Internet Access from SBC & Yahoo! http://sbc.yahoo.com ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List [EMAIL PROTECTED] Automated List Manager [EMAIL PROTECTED]
