bk138/libsshtunnel

Simple SSH tunnel library to let your networking app connect to a host running behind a SSH server.

About

libsshtunnel is a simple SSH tunnel library to let your networking app connect to a host running behind a SSH server.

Example Usage

#include <libsshtunnel.h>

// Callback that handles the SSH server's fingerprint.
// For the example, accepts any fingerprint, but normally
// you would check against saved ones etc.
int ssh_fingerprint_check(void *client,
                          const char *fingerprint,
                          int fingerprint_len,
                          const char *host) {
    return 0;
}

// No extended error checking here for the sake of API showoff.
int main () {
    // Init crypto backend, has to be called only once.
    ssh_tunnel_init();

    // Open a tunnel. This one uses password auth, there also is a variant using the private key.
    ssh_tunnel_t *t = ssh_tunnel_open_with_password("ssh.server.net",       // Hostname of SSH server
                                                    "username",             // SSH user name
                                                    "password",             // SSH user's password
                                                    "localhost",            // Remote service is running directly on SSH server
                                                     26000,                 // Port of remote service
                                                     NULL,                  // You can give an application pointer here that's handed to the callbacks.
                                                     ssh_fingerprint_check, // SSH fingerprint check callback
                                                     NULL);                 // Callback for error reporting, can be omitted
    if(t) {
        // Initial tunnel creation succeeded; you can now let your code connect
        // to the local end of the tunnel:
        // Your client will get connected to the server running on
        // "ssh.server.net", port 26000, as specified above.
        my_client_connect("localhost", ssh_tunnel_get_port(t));

       // Your other logic here...
    }

    // Closes the tunnel and frees memory.
    ssh_tunnel_close(t);

    return 0;
}

Building

libsshtunnel uses CMake, thus it's:

mkdir build
cd build
cmake ..
cmake --build .

License

libsshtunnel is licensed under the BSD 3-Clause License. See COPYING for more information.

libsshtunnel's Issues

Make it safe to call close from error callback

Right now, calling close from the error callback is explicitly forbidden in the docs because thrd_join() on self will not work.

It could be possible with the following scheme:

• have a detached thread instead of joinable
• close sets flag and signals condition variable, thread either terminates itself and waits for cond or is terminated by flag and then does not check cond

Add unit tests