| 1 | n/a | #!/usr/bin/env python3 |
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| 2 | n/a | # |
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| 3 | n/a | # Send/receive UDP multicast packets. |
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| 4 | n/a | # Requires that your OS kernel supports IP multicast. |
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| 5 | n/a | # |
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| 6 | n/a | # Usage: |
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| 7 | n/a | # mcast -s (sender, IPv4) |
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| 8 | n/a | # mcast -s -6 (sender, IPv6) |
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| 9 | n/a | # mcast (receivers, IPv4) |
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| 10 | n/a | # mcast -6 (receivers, IPv6) |
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| 11 | n/a | |
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| 12 | n/a | MYPORT = 8123 |
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| 13 | n/a | MYGROUP_4 = '225.0.0.250' |
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| 14 | n/a | MYGROUP_6 = 'ff15:7079:7468:6f6e:6465:6d6f:6d63:6173' |
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| 15 | n/a | MYTTL = 1 # Increase to reach other networks |
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| 16 | n/a | |
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| 17 | n/a | import time |
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| 18 | n/a | import struct |
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| 19 | n/a | import socket |
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| 20 | n/a | import sys |
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| 21 | n/a | |
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| 22 | n/a | def main(): |
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| 23 | n/a | group = MYGROUP_6 if "-6" in sys.argv[1:] else MYGROUP_4 |
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| 24 | n/a | |
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| 25 | n/a | if "-s" in sys.argv[1:]: |
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| 26 | n/a | sender(group) |
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| 27 | n/a | else: |
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| 28 | n/a | receiver(group) |
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| 29 | n/a | |
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| 30 | n/a | |
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| 31 | n/a | def sender(group): |
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| 32 | n/a | addrinfo = socket.getaddrinfo(group, None)[0] |
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| 33 | n/a | |
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| 34 | n/a | s = socket.socket(addrinfo[0], socket.SOCK_DGRAM) |
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| 35 | n/a | |
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| 36 | n/a | # Set Time-to-live (optional) |
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| 37 | n/a | ttl_bin = struct.pack('@i', MYTTL) |
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| 38 | n/a | if addrinfo[0] == socket.AF_INET: # IPv4 |
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| 39 | n/a | s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl_bin) |
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| 40 | n/a | else: |
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| 41 | n/a | s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, ttl_bin) |
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| 42 | n/a | |
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| 43 | n/a | while True: |
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| 44 | n/a | data = repr(time.time()).encode('utf-8') + b'\0' |
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| 45 | n/a | s.sendto(data, (addrinfo[4][0], MYPORT)) |
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| 46 | n/a | time.sleep(1) |
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| 47 | n/a | |
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| 48 | n/a | |
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| 49 | n/a | def receiver(group): |
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| 50 | n/a | # Look up multicast group address in name server and find out IP version |
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| 51 | n/a | addrinfo = socket.getaddrinfo(group, None)[0] |
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| 52 | n/a | |
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| 53 | n/a | # Create a socket |
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| 54 | n/a | s = socket.socket(addrinfo[0], socket.SOCK_DGRAM) |
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| 55 | n/a | |
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| 56 | n/a | # Allow multiple copies of this program on one machine |
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| 57 | n/a | # (not strictly needed) |
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| 58 | n/a | s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
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| 59 | n/a | |
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| 60 | n/a | # Bind it to the port |
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| 61 | n/a | s.bind(('', MYPORT)) |
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| 62 | n/a | |
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| 63 | n/a | group_bin = socket.inet_pton(addrinfo[0], addrinfo[4][0]) |
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| 64 | n/a | # Join group |
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| 65 | n/a | if addrinfo[0] == socket.AF_INET: # IPv4 |
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| 66 | n/a | mreq = group_bin + struct.pack('=I', socket.INADDR_ANY) |
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| 67 | n/a | s.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq) |
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| 68 | n/a | else: |
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| 69 | n/a | mreq = group_bin + struct.pack('@I', 0) |
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| 70 | n/a | s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, mreq) |
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| 71 | n/a | |
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| 72 | n/a | # Loop, printing any data we receive |
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| 73 | n/a | while True: |
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| 74 | n/a | data, sender = s.recvfrom(1500) |
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| 75 | n/a | while data[-1:] == '\0': data = data[:-1] # Strip trailing \0's |
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| 76 | n/a | print(str(sender) + ' ' + repr(data)) |
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| 77 | n/a | |
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| 78 | n/a | |
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| 79 | n/a | if __name__ == '__main__': |
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| 80 | n/a | main() |
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