SSDP PACKET SENDER 173.32.43.8 CODE

Just another answer to explain some subtle points in the code of the other answers: Above example generates 8 byte setsockopt call where first four bytes define multicast_group and second four bytes define interface_ip. Shortest is form is 8 bytes long and longer is 12 bytes long. Linux socket documentation (see man 7 ip) introduces two forms of ip_mreqn structure for IP_ADD_MEMBERSHIP option. Python forwards setsockopt method call to native C socket interface.

I will try to describe what happens underneath the hood when exercising setsockopt call for python socket object. Please be advised that typical example uses 4sl as format and it is not aligned with actual OS socket interface structure.

Issue for all of them are using struct.pack incorrectly. I noticed that lot of examples around Internet works by accident in fact. All you need to take care of is just set correct destination IP address in sendto() method. If you have single NIC in your system sending such packets does not differ from usual UDP frames sending. Sending multicast IP frames is straight forward. S.setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, str(mreq))įirstly it creates socket, binds it and triggers triggers multicast group joining by issuing setsockopt. Mreq = inet_aton(multicast_group) + inet_aton(interface_ip) Multicast mode of operation such as joining and dropping group membership can be accomplished by setsockopt only.īasic program for receiving multicast IP packet can look like: from socket import * Due to portability and stability of Python environment many of socket options are directly forwarded to native socket setsockopt call. In order to Join multicast group Python uses native OS socket interface. Socket.inet_aton(MCAST_GRP) + socket.inet_aton(host)) tsockopt(socket.SOL_IP, socket.IP_ADD_MEMBERSHIP, tsockopt(socket.SOL_IP, socket.IP_MULTICAST_IF, socket.inet_aton(host)) Host = socket.gethostbyname(socket.gethostname()) tsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1) Multicast receiver that reads from a multicast group and prints hex data to the console: #!/usr/bin/env python ndto('Hello World!', (MCAST_GRP, MCAST_PORT)) tsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 32) Multicast sender that broadcasts to a multicast group: #!/usr/bin/env python It is based off the examples from which didn't work. # For Python 3, change next line to 'ndto(b'robot'. tsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, MULTICAST_TTL) # for all packets sent, after two hops on the network the packet will not # For Python 3, change next line to 'print(sock.recv(10240))' tsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq) Mreq = struct.pack('4sl', socket.inet_aton(MCAST_GRP), socket.INADDR_ANY) # on this port, receives ALL multicast groups tsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) Sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)

Ssdp packet sender 173.32.43.8