int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
 {
-       int err;
+       int err = 0;
        struct ip_mreqn imr;
        u32 addr = msf->imsf_multiaddr;
        struct ip_mc_socklist *pmc;
        struct in_device *in_dev;
        struct inet_sock *inet = inet_sk(sk);
        struct ip_sf_socklist *newpsl, *psl;
+       int leavegroup = 0;
 
        if (!MULTICAST(addr))
                return -EINVAL;
                goto done;
        }
 
+       /* special case - (INCLUDE, empty) == LEAVE_GROUP */
+       if (msf->imsf_fmode == MCAST_INCLUDE && msf->imsf_numsrc == 0) {
+               leavegroup = 1;
+               goto done;
+       }
+
        for (pmc=inet->mc_list; pmc; pmc=pmc->next) {
                if (pmc->multi.imr_multiaddr.s_addr == msf->imsf_multiaddr &&
                    pmc->multi.imr_ifindex == imr.imr_ifindex)
        err = 0;
 done:
        rtnl_shunlock();
+       if (leavegroup)
+               err = ip_mc_leave_group(sk, &imr);
        return err;
 }
 
 
        }
        write_unlock_bh(&ipv6_sk_mc_lock);
 
-       return -ENOENT;
+       return -EADDRNOTAVAIL;
 }
 
 static struct inet6_dev *ip6_mc_find_dev(struct in6_addr *group, int ifindex)
        struct inet6_dev *idev;
        struct ipv6_pinfo *inet6 = inet6_sk(sk);
        struct ip6_sf_socklist *newpsl, *psl;
+       int leavegroup = 0;
        int i, err;
 
        group = &((struct sockaddr_in6 *)&gsf->gf_group)->sin6_addr;
                return -ENODEV;
        dev = idev->dev;
 
+       if (gsf->gf_fmode == MCAST_INCLUDE && gsf->gf_numsrc == 0) {
+               leavegroup = 1;
+               goto done;
+       }
+
        for (pmc=inet6->ipv6_mc_list; pmc; pmc=pmc->next) {
                if (pmc->ifindex != gsf->gf_interface)
                        continue;
        read_unlock_bh(&idev->lock);
        in6_dev_put(idev);
        dev_put(dev);
+       if (leavegroup)
+               err = ipv6_sock_mc_drop(sk, gsf->gf_interface, group);
        return err;
 }