.

tmcast.py

@@ -5,9 +5,10 @@ from __future__ import print_function
 
 
 import sys, time
-from socket import socket, AF_INET, SOCK_DGRAM, IPPROTO_UDP, SOL_SOCKET, \
-    SO_REUSEADDR, IPPROTO_IP, IP_ADD_MEMBERSHIP, IP_MULTICAST_TTL, IP_MULTICAST_LOOP,   \
-    inet_aton, INADDR_ANY
+from socket import socket, AF_INET, AF_INET6, SOCK_DGRAM, IPPROTO_UDP,          \
+    SOL_SOCKET, SO_REUSEADDR, IPPROTO_IP, IPPROTO_IPV6, IP_ADD_MEMBERSHIP,          \
+    IPV6_JOIN_GROUP, IP_MULTICAST_TTL, IPV6_MULTICAST_HOPS, IP_MULTICAST_LOOP,          \
+    IPV6_MULTICAST_LOOP, inet_pton
 import socket as net
 from struct import pack
 
@@ -16,39 +17,59 @@ from golang import sync, context
 
 
 group4 = '224.1.1.1'
-group6 = 'XXX'
+group6 = 'ff15:7079:7468:6f6e:6465:6d6f:6d63:6173'
 port   =  5678
 
+def _udpsockfor(ipaddr): # -> (sk, isipv6)
+    ip6 = (':' in ipaddr)  # autodetect ip4/ip6 based on group addr
+    if ip6:
+        sk = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP)
+    else:
+        sk = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)
+    return (sk, ip6)
+
+
 # mjoin_tx returns socket prepated to send/receive to/from multicast group:port.
 def mjoin_tx(group, port, ttl=2):
-    # XXX autodetect ip4/ip6 based on group addr
-    sk = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)
+    sk, ip6 = _udpsockfor(group)
 
     # set ttl and default destination address (for tx)
-    sk.setsockopt(IPPROTO_IP, IP_MULTICAST_TTL, pack('b', ttl))
+    bttl = pack('b', ttl)
+    if ip6:
+        sk.setsockopt(IPPROTO_IPV6, IPV6_MULTICAST_HOPS, bttl)
+    else:
+        sk.setsockopt(IPPROTO_IP, IP_MULTICAST_TTL, bttl)
+
     sk.connect((group, port))
 
     # so that what we send is received locally as well
+    if ip6:
+        sk.setsockopt(IPPROTO_IPV6, IPV6_MULTICAST_LOOP, 1)
+    else:
         sk.setsockopt(IPPROTO_IP, IP_MULTICAST_LOOP, 1)
+
     return sk
 
 # mjoin_rx returns socket prepated to send/receive to/from multicast group:port.
 def mjoin_rx(group, port):
-    # XXX autodetect ip4/ip6 based on group addr
-    sk = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)
+    sk, ip6 = _udpsockfor(group)
 
     sk.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
     sk.bind((group, port))  # works for reception even from multiple ifaces
     #sk.bind(('', port))     # XXX and later IP_MULTICAST_ALL=0 ?
 
-    ## join the group (for rx)
-    #mreq = pack("4sl", inet_aton(group), INADDR_ANY)
-    #sk.setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, mreq)
-
     # join the group on all interfaces
     for ifidx, ifname in net.if_nameindex():
         print("joining %s @ [%d]%s" % (group, ifidx, ifname))
-        mreq = pack("4sii", inet_aton(group), INADDR_ANY, ifidx)
+        bifidx = pack("@i", ifidx)
+        if ip6:
+            mreq = inet_pton(AF_INET6, group) + \
+                   bifidx
+            sk.setsockopt(IPPROTO_IPV6, IPV6_JOIN_GROUP, mreq)  # = IPV6_ADD_MEMBERSHIP
+        else:
+            mreq = inet_pton(AF_INET, group)     + \
+                   inet_pton(AF_INET, '0.0.0.0') + \
+                   bifidx
             #print(repr(mreq), len(mreq))
             sk.setsockopt(IPPROTO_IP, IP_ADD_MEMBERSHIP, mreq)