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Merged revisions 72237 via svnmerge from
svn+ssh://[email protected]/python/trunk ........ r72237 | gregory.p.smith | 2009-05-03 11:42:15 -0700 (Sun, 03 May 2009) | 3 lines Issue 5379 - applies patch supplied by philipp hagemeister to fix many problems with the ancient mcast.py demo code. ........
1 parent 05bf1d2 commit 2b1a467

2 files changed

Lines changed: 65 additions & 78 deletions

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‎Demo/sockets/README‎

Lines changed: 1 addition & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -5,17 +5,10 @@ echosvr.py About the simplest TCP server possible.
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finger.py Client for the 'finger' protocol.
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ftp.py A very simple ftp client.
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gopher.py A simple gopher client.
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mcast.py IPv4/v6 multicast example
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radio.py Receive time broadcasts from broadcast.py.
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telnet.py Client for the 'telnet' protocol.
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throughput.py Client and server to measure TCP throughput.
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unixclient.py Unix socket example, client side
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unixserver.py Unix socket example, server side
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udpecho.py Client and server for the UDP echo protocol.
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The following file is only relevant on SGI machines (or other systems
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that support multicast):
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mcast.py A Python translation of
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/usr/people/4Dgifts/examples/network/mcast.c
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(Note that IN.py is in ../../lib/sgi.)
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‎Demo/sockets/mcast.py‎

Lines changed: 64 additions & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -1,93 +1,87 @@
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#!/usr/bin/env python
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#
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# Send/receive UDP multicast packets.
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# Requires that your OS kernel supports IP multicast.
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# This is built-in on SGI, still optional for most other vendors.
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#
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# Usage:
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# mcast -s (sender)
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# mcast -b (sender, using broadcast instead multicast)
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# mcast (receivers)
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# mcast -s (sender, IPv4)
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# mcast -s -6 (sender, IPv6)
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# mcast (receivers, IPv4)
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# mcast -6 (receivers, IPv6)
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MYPORT = 8123
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MYGROUP = '225.0.0.250'
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MYGROUP_4 = '225.0.0.250'
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MYGROUP_6 = 'ff15:7079:7468:6f6e:6465:6d6f:6d63:6173'
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MYTTL = 1 # Increase to reach other networks
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import sys
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import ipaddr
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import time
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import struct
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from socket import *
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import socket
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import sys
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# Main program
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def main():
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flags = sys.argv[1:]
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#
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if flags:
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sender(flags[0])
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group = MYGROUP_6 if "-6" in sys.argv[1:] else MYGROUP_4
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if "-s" in sys.argv[1:]:
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sender(group)
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else:
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receiver(group)
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def _sockfam(ip):
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"""Returns the family argument of socket.socket"""
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if ip.version == 4:
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return socket.AF_INET
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elif ip.version == 6:
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return socket.AF_INET6
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else:
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receiver()
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raise ValueError('IPv' + ip.version + ' is not supported')
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def sender(group):
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group_ip = ipaddr.IP(group)
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s = socket.socket(_sockfam(group_ip), socket.SOCK_DGRAM)
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# Sender subroutine (only one per local area network)
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def sender(flag):
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s = socket(AF_INET, SOCK_DGRAM)
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if flag == '-b':
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s.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
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mygroup = '<broadcast>'
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# Set Time-to-live (optional)
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ttl_bin = struct.pack('@i', MYTTL)
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if group_ip.version == 4:
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s.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, ttl_bin)
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else:
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mygroup = MYGROUP
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ttl = struct.pack('b', 1) # Time-to-live
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s.setsockopt(IPPROTO_IP, IP_MULTICAST_TTL, ttl)
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while 1:
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data = repr(time.time())
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## data = data + (1400 - len(data)) * '\0'
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s.sendto(data, (mygroup, MYPORT))
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s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_MULTICAST_HOPS, ttl_bin)
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while True:
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data = repr(time.time()).encode('utf-8') + b'\0'
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s.sendto(data, (group_ip.ip_ext_full, MYPORT))
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time.sleep(1)
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# Receiver subroutine (as many as you like)
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def receiver():
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# Open and initialize the socket
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s = openmcastsock(MYGROUP, MYPORT)
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#
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# Loop, printing any data we receive
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while 1:
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data, sender = s.recvfrom(1500)
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while data[-1:] == '\0': data = data[:-1] # Strip trailing \0's
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print(sender, ':', repr(data))
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def receiver(group):
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group_ip = ipaddr.IP(group)
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# Open a UDP socket, bind it to a port and select a multicast group
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def openmcastsock(group, port):
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# Import modules used only here
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import string
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import struct
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#
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# Create a socket
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s = socket(AF_INET, SOCK_DGRAM)
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#
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s = socket.socket(_sockfam(group_ip), socket.SOCK_DGRAM)
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# Allow multiple copies of this program on one machine
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# (not strictly needed)
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s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
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#
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s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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# Bind it to the port
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s.bind(('', port))
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#
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# Look up multicast group address in name server
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# (doesn't hurt if it is already in ddd.ddd.ddd.ddd format)
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group = gethostbyname(group)
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#
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# Construct binary group address
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bytes = list(map(int, string.split(group, ".")))
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grpaddr = 0
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for byte in bytes: grpaddr = (grpaddr << 8) | byte
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#
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# Construct struct mreq from grpaddr and ifaddr
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ifaddr = INADDR_ANY
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mreq = struct.pack('ll', htonl(grpaddr), htonl(ifaddr))
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#
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# Add group membership
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s.setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, mreq)
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#
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return s
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93-
main()
69+
s.bind(('', MYPORT))
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71+
# Join group
72+
if group_ip.version == 4: # IPv4
73+
mreq = group_ip.packed + struct.pack('=I', socket.INADDR_ANY)
74+
s.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
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else:
76+
mreq = group_ip.packed + struct.pack('@I', 0)
77+
s.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_JOIN_GROUP, mreq)
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79+
# Loop, printing any data we receive
80+
while True:
81+
data, sender = s.recvfrom(1500)
82+
while data[-1:] == '\0': data = data[:-1] # Strip trailing \0's
83+
print(str(sender) + ' ' + repr(data))
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85+
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if __name__ == '__main__':
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main()

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