[IPV4]: (INCLUDE,empty)/leave-group equivalence for full-state MSF APIs & errno fix

1) Adds (INCLUDE, empty)/leave-group equivalence to the full-state 
   multicast source filter APIs (IPv4 and IPv6)

2) Fixes an incorrect errno in the IPv6 leave-group (ENOENT should be
   EADDRNOTAVAIL)
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/igmp.c

@@ -1849,13 +1849,14 @@ done:
 
 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;
@@ -1875,6 +1876,12 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
 		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)
@@ -1915,6 +1922,8 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
 	err = 0;
 done:
 	rtnl_shunlock();
+	if (leavegroup)
+		err = ip_mc_leave_group(sk, &imr);
 	return err;
 }
 

net/ipv6/mcast.c

@@ -281,7 +281,7 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, struct in6_addr *addr)
 	}
 	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)
@@ -492,6 +492,7 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf)
 	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;
@@ -508,6 +509,11 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf)
 		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;
@@ -554,6 +560,8 @@ done:
 	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;
 }