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,'\nwaiting 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)