Benjamin Peterson | 90f5ba5 | 2010-03-11 22:53:45 +0000 | [diff] [blame] | 1 | #!/usr/bin/env python3 |
Georg Brandl | 856898b | 2010-12-30 22:11:50 +0000 | [diff] [blame] | 2 | |
| 3 | """ |
| 4 | Send/receive UDP multicast packets. |
| 5 | Requires that your OS kernel supports IP multicast. |
| 6 | |
| 7 | Usage: |
| 8 | mcast -s (sender, IPv4) |
| 9 | mcast -s -6 (sender, IPv6) |
| 10 | mcast (receivers, IPv4) |
| 11 | mcast -6 (receivers, IPv6) |
| 12 | """ |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 13 | |
| 14 | MYPORT = 8123 |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 15 | MYGROUP_4 = '225.0.0.250' |
| 16 | MYGROUP_6 = 'ff15:7079:7468:6f6e:6465:6d6f:6d63:6173' |
| 17 | MYTTL = 1 # Increase to reach other networks |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 18 | |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 19 | import time |
| 20 | import struct |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 21 | import socket |
| 22 | import sys |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 23 | |
Guido van Rossum | bd07b31 | 1992-11-16 16:54:45 +0000 | [diff] [blame] | 24 | def main(): |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 25 | group = MYGROUP_6 if "-6" in sys.argv[1:] else MYGROUP_4 |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 26 | |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 27 | if "-s" in sys.argv[1:]: |
| 28 | sender(group) |
Tim Peters | e6ddc8b | 2004-07-18 05:56:09 +0000 | [diff] [blame] | 29 | else: |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 30 | receiver(group) |
| 31 | |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 32 | |
| 33 | def sender(group): |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 34 | addrinfo = socket.getaddrinfo(group, None)[0] |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 35 | |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 36 | s = socket.socket(addrinfo[0], socket.SOCK_DGRAM) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 37 | |
| 38 | # Set Time-to-live (optional) |
| 39 | ttl_bin = struct.pack('@i', MYTTL) |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 40 | if addrinfo[0] == socket.AF_INET: # IPv4 |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 41 | s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl_bin) |
| 42 | else: |
| 43 | s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, ttl_bin) |
| 44 | |
| 45 | while True: |
| 46 | data = repr(time.time()).encode('utf-8') + b'\0' |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 47 | s.sendto(data, (addrinfo[4][0], MYPORT)) |
Tim Peters | e6ddc8b | 2004-07-18 05:56:09 +0000 | [diff] [blame] | 48 | time.sleep(1) |
Guido van Rossum | 4fab6a5 | 1992-09-08 21:19:55 +0000 | [diff] [blame] | 49 | |
Guido van Rossum | a1b51f3 | 1992-10-25 19:20:47 +0000 | [diff] [blame] | 50 | |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 51 | def receiver(group): |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 52 | # Look up multicast group address in name server and find out IP version |
| 53 | addrinfo = socket.getaddrinfo(group, None)[0] |
Guido van Rossum | bd07b31 | 1992-11-16 16:54:45 +0000 | [diff] [blame] | 54 | |
Tim Peters | e6ddc8b | 2004-07-18 05:56:09 +0000 | [diff] [blame] | 55 | # Create a socket |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 56 | s = socket.socket(addrinfo[0], socket.SOCK_DGRAM) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 57 | |
Tim Peters | e6ddc8b | 2004-07-18 05:56:09 +0000 | [diff] [blame] | 58 | # Allow multiple copies of this program on one machine |
| 59 | # (not strictly needed) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 60 | s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
| 61 | |
Tim Peters | e6ddc8b | 2004-07-18 05:56:09 +0000 | [diff] [blame] | 62 | # Bind it to the port |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 63 | s.bind(('', MYPORT)) |
| 64 | |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 65 | group_bin = socket.inet_pton(addrinfo[0], addrinfo[4][0]) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 66 | # Join group |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 67 | if addrinfo[0] == socket.AF_INET: # IPv4 |
| 68 | mreq = group_bin + struct.pack('=I', socket.INADDR_ANY) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 69 | s.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq) |
| 70 | else: |
Amaury Forgeot d'Arc | 3783143 | 2009-06-23 22:01:54 +0000 | [diff] [blame] | 71 | mreq = group_bin + struct.pack('@I', 0) |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 72 | s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, mreq) |
| 73 | |
| 74 | # Loop, printing any data we receive |
| 75 | while True: |
| 76 | data, sender = s.recvfrom(1500) |
| 77 | while data[-1:] == '\0': data = data[:-1] # Strip trailing \0's |
| 78 | print(str(sender) + ' ' + repr(data)) |
Guido van Rossum | bd07b31 | 1992-11-16 16:54:45 +0000 | [diff] [blame] | 79 | |
| 80 | |
Gregory P. Smith | 2b1a467 | 2009-05-03 19:09:56 +0000 | [diff] [blame] | 81 | if __name__ == '__main__': |
| 82 | main() |