Tunnels UDP multicast packets over TCP.
Intended to be used like udptunnel but when multicasting with loopback enabled
is required (since udptunnel disables multicast loopback it cannot be used to
receive multicast packets and tunnel them from the same host it is running on and
sends received data on the multicast group).
It can run either in TCP server (multi-threaded supporting multiple concurrent TCP clients) or TCP client mode.
For each TCP connection 2 sockets (in addition to the one for the TCP data exchange, 1 to send UDP multicast packets and 1 to receive them) and 5 threads are spawned (1 to control the others and 2 pairs of reception-transmission threads for TCP and UDP). The 2 distinct sockets for UDP multicast are used in order to utilize a different (random) port for transmission in order to be able to recognize (and discard) multicast packets that have originated from the instance itself. Two queues are used for each TCP connection to buffer incoming packets (one for TCP, one for UDP) before transmission.
The TCP client automatically retries every 1 second to connect if the connection attempt fails or the connection is broken.
Python 3.x
usage: mcasttunnel [-h] [-s] -a ADDRESS -p PORT -i MCAST_INTERFACE_ADDR -g
MCAST_GRP_ADDR -r MCAST_GRP_PORT -t MCAST_TTL [-v]
Tunnel UDP multicast packets over TCP
optional arguments:
-h, --help show this help message and exit
-s, --server if set run as TCP server, client otherwise
-a ADDRESS, --address ADDRESS
the server's address if running as client, the address
of the network interface to listen on when running as
server (0.0.0.0 for any interface)
-p PORT, --port PORT the port the server listens (or should listen) on
-i MCAST_INTERFACE_ADDR, --mcast_interface_addr MCAST_INTERFACE_ADDR
the address of the network interface to be used to
send/receive multicast packets
-g MCAST_GRP_ADDR, --mcast_grp_addr MCAST_GRP_ADDR
the IP address of the multicast group
-r MCAST_GRP_PORT, --mcast_grp_port MCAST_GRP_PORT
the port of the multicast group
-t MCAST_TTL, --mcast_ttl MCAST_TTL
the TTL for multicast packets
-v, --verbose enables verbose output