Merged revisions 72237 via svnmerge from

svn+ssh://pythondev@svn.python.org/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.
........
This commit is contained in:
Gregory P. Smith 2009-05-03 19:09:56 +00:00
parent 05bf1d23f6
commit 2b1a467be9
2 changed files with 65 additions and 78 deletions

View File

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

View File

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