Messages in this thread | | | Date | Thu, 6 Mar 2003 09:38:14 -0800 | From | David Ashley <> | Subject | Possible socket problem? |
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I'm seeing some strange behaviour with sockets under 2.4.20, and the same thing on 2.4.18. I haven't tried any other kernel versions though or done any more investigation, but all signs seem to point to a socket problem in the kernel.
My program is reading from a socket produced like this: sock=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); I connect() the socket to an external server (an IMAP mail server). The server throws lots of data down the line. The indication is that if the socket's receive buffer fills up, I can no longer read from the socket, the read just blocks forever. Same if I select() on the socket, it never reports data is ready. I can tcpdump and see plenty of data having arrived after the point where the last read succeeded.
The problem goes away if I do this: i=4096; j=setsockopt(sock,SOL_SOCKET,SO_RCVBUF,&i,sizeof(i));
It still occured when I set the RCVBUF size to 50000.
When the freeze happens I can find the last data received from the socket in the tcpdump log, and it always is the last bytes in a single tcp packet. More tcp packets follow, but they don't cause the read() to return.
I'm not doing any ioctl's or weird stuff, and I only read() or write() to the socket.
-Dave
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