[noPoll] Issue with using Secure Sockets client connecion (wss://) from Windows

[Kale, Rahul]

Hello,

Any resolution to the issue regarding this?
In spite of the workaround mentioned below, we see this fail
in certain cases.

Thanks,

Rahul

Rahul Kale

IP Video Systems
Barco, Inc
1287 Anvilwood Ave
Sunnyvale, CA  94089


From: nopoll-bounces en lists.aspl.es [mailto:nopoll-bounces en lists.aspl.es] On Behalf Of Kale, Rahul
Sent: Tuesday, September 08, 2015 6:35 PM
To: nopoll en lists.aspl.es
Subject: [noPoll] Issue with using Secure Sockets client connecion (wss://) from Windows


Hello,

I am facing an issue with using noPoll library for Secure Websockets (wss://)
client connection on Windows platform. Basically, the first connection from
the same binary works but subsequent connections do not work reliably.
When I tried to debug the issue, by enabling logs, the problem goes away.
Strangely, if I install my own log handler with an empty (do nothing)
implementation, the problem also goes away.
I have been trying to track down the problem the past week and finally have
something to report.

Firstly, I have isolated the code (see below) to the bare minimum below for you to reproduce the
issue. The code makes 100 back to back connections in a loop and exits the loop
early if it fails. This code rarely lasts for 2 or more loops. However if you
enable logs (setting nopoll_log_set_handler to true) or install a log
handler (using nopoll_log_set_handler), it will make 100 successful connections.

Since logging did not help, I ended up compiling the noPoll source myself for further
debugging. Since I am using VS 2008, I had to fix the code here and there to get it
to compile and also had to add __declspec(dllexport) to most functions in the header file.
By adding trial and error printfs I narrowed down the spot when it fails.
Whenever the connect fails, the SSL_connect() function errors out with
SSL_ERROR_SYSCALL at around line 756 in nopoll_conn.c.

Assuming that there is some timing issue (since logging adds just enough delay),
I have put a temporary fix as a workaround which fixes the issue: I added
a nopoll_sleep() just before SSL_connect() like so:

    nopoll_sleep (10000);
    while (SSL_connect (conn->ssl) <= 0) {
    ...


I am sure you will find the root cause and have a better fix.

Here is the sample code:

#include "nopoll.h"

static void noPollLogger(noPollCtx *ctx, noPollDebugLevel level, const char *log_msg, noPollPtr user_data) {
    // Do nothing here
}

int ConnectToWebsocket()
{

    noPollCtx * context = nopoll_ctx_new();

    //nopoll_log_set_handler(context, noPollLogger, NULL);
    nopoll_log_enable(context, false);

    noPollConnOpts * opts = nopoll_conn_opts_new();
    nopoll_conn_opts_ssl_peer_verify(opts, false); // disable cert verification
    noPollConn * connection = nopoll_conn_tls_new(context, opts, "10.1.2.3", "443", NULL,
        "wss://10.1.2.3:443/wstunnel/?dst=127.0.0.1:6060", "tunnel-protocol", "some-origin");

    bool connected = true;
    int count = 0;
    while (!nopoll_conn_is_ready(connection)) {
        if (!nopoll_conn_is_ok(connection)) {
            connected = false;
            break;
        }
        nopoll_sleep(10000);
        fprintf(stdout, "Info: Waiting for connection...\n", count++);
    }

    if (connected) {
       fprintf(stdout, "Info: Connected!!\n");
    }
    else {
       fprintf(stdout, "Failed websocket connection\n");
       exit(1);
    }

    nopoll_conn_close(connection);
    nopoll_ctx_unref(context);

    return 0;
}

int main(int argc, char *argv[])
{
    for (int i = 0; i < 100; i++) {
        ConnectToWebsocket();
        fprintf(stderr, "Done Loop %d\n", i);
    }
    return 0;
}

Thanks,

Rahul

Rahul Kale

IP Video Systems
Barco, Inc
1287 Anvilwood Ave
Sunnyvale, CA  94089

Tel  +1 408 400 4238

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