Bi-directional communication using sockets via ssh tunnel

I have a server host (S) and a bunch of clients (C1, C2, C3, ...). I would like to open connection between S and C1, C2, C3 respectively for bi-directional communication. Ideally using sockets. SSH for authorisation purposes is preferred.

Ideally:

1. Client C1 creates SSH reverse tunnel to S, forwarding C1's port so it is accessible on S as it's own port.
2. Client program running on C1 creates a socket and binds to forwarded port.
3. Server program running on S creates a socket and binds to forwarded port.
4. Client and server can exchange data.

Is something like that possible? I tried coding up a draft using Python but to no avail:

Firstly, I run on C1: ssh -N -R 9999:localhost:15432 root@example.com - OK

Secondly, on server I run:

import socket

serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(('localhost', 9999))
serversocket.listen(5)

while True:
    connection, address = serversocket.accept()
    buf = connection.recv(64)
    if len(buf) > 0:
        print buf
        break

Thirdly, on client I run:

import socket

clientsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
clientsocket.connect(('localhost', 15432))
clientsocket.send('hello')

But I'm getting socket.error: [Errno 111] Connection refused on client. Also if I set up tunnel first and then launch server program, I'm getting [Errno 98] Address already in use. It only works when I first start the program, then set up a tunnel.

If aforementioned concept does not make sense, what would you suggest to create sort of synchronisation tool so any client listens for queries from the server and can respond with data? (preferrably in Python).

Thanks in advance.