python-组播

 #!/usr/bin/python 
#coding=utf-8
#发送端
import sys,struct,socket
from time import sleep

message="hello"
message1="nihao"

multicast_group=('224.3.29.73',10003)
multicast_group1=('224.3.29.74',10004)

sock=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

sock.timeout(3)

ttl=struct.pack('b',1)  #将数字1转换成无符号字符类型.在python中没有这种类型,但是内核需要,所以转换

sock.setsockopt(socket.IPPROTO_IP,socket.IP_MULTICAST_TTL,ttl)

try:
    while 1:
        sleep(2)
        sent=sock.sendto(message,multicast_group)
        sent=sock.sendto(message1,multicast_group1)

        print >>sys.stderr,"waiting to receive"

        try:
            data,server=sock.recvfrom(1024)
        except sock.timeout:
            print >>sys.stderr,"time out ,no more response"
            break
        else:
            print >>sys.stderr,"received %s from %s"%(data,server)
finally:
    print >>sys.stderr,"closing socket"
    sock.close()

#!/usr/bin/python
#接收端
import socket
import sys
import struct
 
multicast_group = '224.3.29.72'
server_address = ('',10001)
 
sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
 
sock.bind(server_address)
 
group = socket.inet_aton(multicast_group)
mreq = struct.pack('4sL',group,socket.INADDR_ANY)
sock.setsockopt(socket.IPPROTO_IP,socket.IP_ADD_MEMBERSHIP,mreq)
 
while True:
    print >>sys.stderr,'
waiting to receive message'
    data,address = sock.recvfrom(1024)
 
    print >>sys.stderr,'received %s bytes from %s'%(len(data),data)
    print >>sys.stderr,'sending acknowledgement to',address
    sock.sendto('gaozhiqiangf',address)