55 lines
1.4 KiB
Python
55 lines
1.4 KiB
Python
|
# Send/receive UDP multicast packets (SGI)
|
||
|
# After /usr/people/4Dgifts/examples/network/mcast.c
|
||
|
# Usage:
|
||
|
# mcast -s (sender)
|
||
|
# mcast (receivers)
|
||
|
|
||
|
MYPORT = 8123
|
||
|
MYGROUP_BYTES = 225, 0, 0, 250
|
||
|
|
||
|
import sys
|
||
|
import time
|
||
|
import struct
|
||
|
from socket import *
|
||
|
from SOCKET import *
|
||
|
from IN import *
|
||
|
|
||
|
sender = (sys.argv[1:2] == ['-s'])
|
||
|
|
||
|
s = socket(AF_INET, SOCK_DGRAM)
|
||
|
|
||
|
if sender:
|
||
|
# Ugly: construct decimal IP address string from MYGROUP_BYTES
|
||
|
mygroup = ''
|
||
|
for byte in MYGROUP_BYTES: mygroup = mygroup + '.' + `byte`
|
||
|
mygroup = mygroup[1:]
|
||
|
ttl = struct.pack('b', 1) # Time-to-live
|
||
|
s.setsockopt(IPPROTO_IP, IP_MULTICAST_TTL, ttl)
|
||
|
while 1:
|
||
|
data = `time.time()` + '\n'
|
||
|
s.sendto(data, (mygroup, MYPORT))
|
||
|
time.sleep(5)
|
||
|
else:
|
||
|
# Bind the socket to my port
|
||
|
s.bind('', MYPORT)
|
||
|
|
||
|
# Allow multiple copies of this program on one machine
|
||
|
s.setsockopt(SOL_SOCKET, SO_REUSEPORT, 1) # (Not strictly needed)
|
||
|
|
||
|
# Ugly: construct binary group address from MYGROUP_BYTES
|
||
|
grpaddr = 0
|
||
|
for byte in MYGROUP_BYTES: grpaddr = (grpaddr << 8) | byte
|
||
|
|
||
|
# Construct struct mreq from grpaddr and ifaddr
|
||
|
ifaddr = INADDR_ANY
|
||
|
mreq = struct.pack('ll', grpaddr, ifaddr)
|
||
|
|
||
|
# Add group membership
|
||
|
s.setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, mreq)
|
||
|
|
||
|
# Loop, printing any data we receive
|
||
|
while 1:
|
||
|
data, sender = s.recvfrom(1500)
|
||
|
while data[-1:] == '\0': data = data[:-1] # Strip trailing \0's
|
||
|
print sender, ':', `data`
|