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Re: asynchronous channel write

Hi Torsten,

the "trick" is called ssh_set_blocking(session, 0);

But be careful, this affects everything in the session.

My write loop looks lile this:

    blocking = ssh_is_blocking(session);
    ssh_set_blocking(session, 0);

    if (len > 0) {
        if (ssh_channel_is_open(channel)) {
            wr = 0;
            do {
                i = ssh_channel_write(channel, buf, len);
                if (i < 0) {
                    log("Error writing on the direct-tcpip channel: %d", i);
                    len = wr;
                wr += i;
                log("channel_write (%d from %d)", wr, len);
            } while (i > 0 && wr < len);
        else {
            log("Can't write on closed channel!");

    ssh_set_blocking(session, blocking);


On 13.01.20 17:48, Torsten Kuehnel wrote:
> Working on the reference implementation of the ncot library i am
> confronted with the follwoing use case:
> Data packets are to be received and send from/to several simultaneous
> open ssh-like encrypted channels to instances of the same program
> running on other hosts over the network.
> The one client-server connection -> one thread paradigm does not fit
> so well. Packets have to be validated, act upon and processed in
> different ways, and need to be resend to other connections - this is
> the real part of the implementation.
> So my approach currently is the following one:
> A mainloop with ssh_event_dopoll manages to call my channel callbacks
> i have established during initialization of the several sessions. But
> when it comes to write my packets over the channels, libssh only offers
> a blocking ssh_channel_write call what is not what i want.
> When the poll returns with write possible, i usually try to write as
> much as i can and send tells me how much succeded. How can i achieve
> this behaviour using libssh ?
> thanks for any insights in advance, keep up the good work !
> -- Torsten Kuehnel
> <tdkuehnel@xxxxxxxxxxxxxxxxxxxxx>

Re: asynchronous channel writeTorsten Kuehnel <tdkuehnel@xxxxxxxxxxxxxxxxxxxxx>
asynchronous channel writeTorsten Kuehnel <tdkuehnel@xxxxxxxxxxxxxxxxxxxxx>
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