FM / sockets

/usr/lib64/python2.6/Demo/sockets

Name	Size	Mode	Actions
broadcast.py	283	0644	edit dl rm
broadcast.pyc	546	0644	edit dl rm
broadcast.pyo	546	0644	edit dl rm
echosvr.py	742	0755	edit dl rm
echosvr.pyc	830	0644	edit dl rm
echosvr.pyo	830	0644	edit dl rm
finger.py	1263	0755	edit dl rm
finger.pyc	1174	0644	edit dl rm
finger.pyo	1174	0644	edit dl rm
ftp.py	3928	0644	edit dl rm
ftp.pyc	2973	0644	edit dl rm
ftp.pyo	2973	0644	edit dl rm
gopher.py	9787	0755	edit dl rm
gopher.pyc	10427	0644	edit dl rm
gopher.pyo	10427	0644	edit dl rm
mcast.py	2387	0644	edit dl rm
mcast.pyc	2094	0644	edit dl rm
mcast.pyo	2094	0644	edit dl rm
radio.py	287	0644	edit dl rm
radio.pyc	470	0644	edit dl rm
radio.pyo	470	0644	edit dl rm
README	814	0644	edit dl rm
rpython.py	717	0755	edit dl rm
rpython.pyc	987	0644	edit dl rm
rpython.pyo	987	0644	edit dl rm
rpythond.py	1217	0755	edit dl rm
rpythond.pyc	1337	0644	edit dl rm
rpythond.pyo	1337	0644	edit dl rm
telnet.py	3013	0755	edit dl rm
telnet.pyc	2182	0644	edit dl rm
telnet.pyo	2182	0644	edit dl rm
throughput.py	2088	0755	edit dl rm
throughput.pyc	2489	0644	edit dl rm
throughput.pyo	2489	0644	edit dl rm
udpecho.py	1471	0755	edit dl rm
udpecho.pyc	2039	0644	edit dl rm
udpecho.pyo	2039	0644	edit dl rm
unicast.py	230	0644	edit dl rm
unicast.pyc	455	0644	edit dl rm
unicast.pyo	455	0644	edit dl rm
unixclient.py	232	0644	edit dl rm
unixclient.pyc	424	0644	edit dl rm
unixclient.pyo	424	0644	edit dl rm
unixserver.py	414	0644	edit dl rm
unixserver.pyc	599	0644	edit dl rm
unixserver.pyo	599	0644	edit dl rm

Edit: /usr/lib64/python2.6/Demo/sockets/mcast.py (2387B)

# 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)

MYPORT = 8123
MYGROUP = '225.0.0.250'

import sys
import time
import struct
from socket import *

# Main program
def main():
    flags = sys.argv[1:]
    #
    if flags:
        sender(flags[0])
    else:
        receiver()

# 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>'
    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))
        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)

# 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)
    #
    # Allow multiple copies of this program on one machine
    # (not strictly needed)
    s.setsockopt(SOL_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 = 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

main()

cmd: