[IPV6] MLDv2: fix change records when transitioning to/from inactive

The following patch fixes these problems in MLDv2:

1) Add/remove "delete" records for sending change reports when
        addition of a filter results in that filter transitioning to/from
        inactive. [same as recent IPv4 IGMPv3 fix]
2) Remove 2 redundant "group_type" checks (can't be IPV6_ADDR_ANY
        within that loop, so checks are always true)
3) change an is_in() "return 0" to "return type == MLD2_MODE_IS_INCLUDE".
        It should always be "0" to get here, but it improves code locality 
        to not assume it, and if some race allowed otherwise, doing
        the check would return the correct result.
Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/mcast.c

@@ -1252,8 +1252,7 @@ int igmp6_event_query(struct sk_buff *skb)
 		}
 	} else {
 		for (ma = idev->mc_list; ma; ma=ma->next) {
-			if (group_type != IPV6_ADDR_ANY &&
-			    !ipv6_addr_equal(group, &ma->mca_addr))
+			if (!ipv6_addr_equal(group, &ma->mca_addr))
 				continue;
 			spin_lock_bh(&ma->mca_lock);
 			if (ma->mca_flags & MAF_TIMER_RUNNING) {
@@ -1268,11 +1267,10 @@ int igmp6_event_query(struct sk_buff *skb)
 					ma->mca_flags &= ~MAF_GSQUERY;
 			}
 			if (!(ma->mca_flags & MAF_GSQUERY) ||
-			   mld_marksources(ma, ntohs(mlh2->nsrcs), mlh2->srcs))
+			    mld_marksources(ma, ntohs(mlh2->nsrcs), mlh2->srcs))
 				igmp6_group_queried(ma, max_delay);
 			spin_unlock_bh(&ma->mca_lock);
-			if (group_type != IPV6_ADDR_ANY)
-				break;
+			break;
 		}
 	}
 	read_unlock_bh(&idev->lock);
@@ -1351,7 +1349,7 @@ static int is_in(struct ifmcaddr6 *pmc, struct ip6_sf_list *psf, int type,
 			 * in all filters
 			 */
 			if (psf->sf_count[MCAST_INCLUDE])
-				return 0;
+				return type == MLD2_MODE_IS_INCLUDE;
 			return pmc->mca_sfcount[MCAST_EXCLUDE] ==
 				psf->sf_count[MCAST_EXCLUDE];
 		}
@@ -1966,7 +1964,7 @@ static void sf_markstate(struct ifmcaddr6 *pmc)
 
 static int sf_setstate(struct ifmcaddr6 *pmc)
 {
-	struct ip6_sf_list *psf;
+	struct ip6_sf_list *psf, *dpsf;
 	int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];
 	int qrv = pmc->idev->mc_qrv;
 	int new_in, rv;
@@ -1978,8 +1976,48 @@ static int sf_setstate(struct ifmcaddr6 *pmc)
 				!psf->sf_count[MCAST_INCLUDE];
 		} else
 			new_in = psf->sf_count[MCAST_INCLUDE] != 0;
-		if (new_in != psf->sf_oldin) {
-			psf->sf_crcount = qrv;
+		if (new_in) {
+			if (!psf->sf_oldin) {
+				struct ip6_sf_list *prev = 0;
+
+				for (dpsf=pmc->mca_tomb; dpsf;
+				     dpsf=dpsf->sf_next) {
+					if (ipv6_addr_equal(&dpsf->sf_addr,
+					    &psf->sf_addr))
+						break;
+					prev = dpsf;
+				}
+				if (dpsf) {
+					if (prev)
+						prev->sf_next = dpsf->sf_next;
+					else
+						pmc->mca_tomb = dpsf->sf_next;
+					kfree(dpsf);
+				}
+				psf->sf_crcount = qrv;
+				rv++;
+			}
+		} else if (psf->sf_oldin) {
+			psf->sf_crcount = 0;
+			/*
+			 * add or update "delete" records if an active filter
+			 * is now inactive
+			 */
+			for (dpsf=pmc->mca_tomb; dpsf; dpsf=dpsf->sf_next)
+				if (ipv6_addr_equal(&dpsf->sf_addr,
+				    &psf->sf_addr))
+					break;
+			if (!dpsf) {
+				dpsf = (struct ip6_sf_list *)
+					kmalloc(sizeof(*dpsf), GFP_ATOMIC);
+				if (!dpsf)
+					continue;
+				*dpsf = *psf;
+				/* pmc->mca_lock held by callers */
+				dpsf->sf_next = pmc->mca_tomb;
+				pmc->mca_tomb = dpsf;
+			}
+			dpsf->sf_crcount = qrv;
 			rv++;
 		}
 	}