[PATCH net-next 10/15] net: bridge: mcast: support for IGMPv3 IGMPV3_ALLOW_NEW_SOURCES report

[Nikolay Aleksandrov <nikolay@cumulusnetworks.com>]

This patch adds handling for the IGMPV3_ALLOW_NEW_SOURCES IGMPv3 report
type and limits it only when multicast_igmp_version == 3. Now that
IGMPv3 handling functions will be managing timers we need to delay their
activation, thus a new argument is added which controls if the timer
should be updated. We also disable host IGMPv3 handling as it's not yet
implemented and could cause inconsistent group state, the host can only
join a group as EXCLUDE {} or leave it.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
---
 net/bridge/br_multicast.c | 113 ++++++++++++++++++++++++++++++++------
 net/bridge/br_private.h   |   7 +++
 2 files changed, 103 insertions(+), 17 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 1dc0964ea3b5..cf76a95f1599 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -721,7 +721,8 @@ void br_multicast_host_leave(struct net_bridge_mdb_entry *mp, bool notify)
 static int br_multicast_add_group(struct net_bridge *br,
 				  struct net_bridge_port *port,
 				  struct br_ip *group,
-				  const unsigned char *src)
+				  const unsigned char *src,
+				  bool update_timer)
 {
 	struct net_bridge_port_group __rcu **pp;
 	struct net_bridge_port_group *p;
@@ -760,7 +761,8 @@ static int br_multicast_add_group(struct net_bridge *br,
 	br_mdb_notify(br->dev, mp, p, RTM_NEWMDB);
 
 found:
-	mod_timer(&p->timer, now + br->multicast_membership_interval);
+	if (update_timer)
+		mod_timer(&p->timer, now + br->multicast_membership_interval);
 
 out:
 	err = 0;
@@ -774,7 +776,8 @@ static int br_ip4_multicast_add_group(struct net_bridge *br,
 				      struct net_bridge_port *port,
 				      __be32 group,
 				      __u16 vid,
-				      const unsigned char *src)
+				      const unsigned char *src,
+				      bool update_timer)
 {
 	struct br_ip br_group;
 
@@ -786,7 +789,7 @@ static int br_ip4_multicast_add_group(struct net_bridge *br,
 	br_group.proto = htons(ETH_P_IP);
 	br_group.vid = vid;
 
-	return br_multicast_add_group(br, port, &br_group, src);
+	return br_multicast_add_group(br, port, &br_group, src, update_timer);
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
@@ -806,7 +809,7 @@ static int br_ip6_multicast_add_group(struct net_bridge *br,
 	br_group.proto = htons(ETH_P_IPV6);
 	br_group.vid = vid;
 
-	return br_multicast_add_group(br, port, &br_group, src);
+	return br_multicast_add_group(br, port, &br_group, src, true);
 }
 #endif
 
@@ -1153,20 +1156,71 @@ void br_multicast_disable_port(struct net_bridge_port *port)
 	spin_unlock(&br->multicast_lock);
 }
 
+/* State          Msg type      New state                Actions
+ * INCLUDE (A)    IS_IN (B)     INCLUDE (A+B)            (B)=GMI
+ * INCLUDE (A)    ALLOW (B)     INCLUDE (A+B)            (B)=GMI
+ * EXCLUDE (X,Y)  ALLOW (A)     EXCLUDE (X+A,Y-A)        (A)=GMI
+ */
+static bool br_multicast_isinc_allow(struct net_bridge_port_group *pg,
+				     __be32 *srcs, u32 nsrcs)
+{
+	struct net_bridge *br = pg->port->br;
+	struct net_bridge_group_src *ent;
+	unsigned long now = jiffies;
+	bool changed = false;
+	struct br_ip src_ip;
+	u32 src_idx;
+
+	memset(&src_ip, 0, sizeof(src_ip));
+	src_ip.proto = htons(ETH_P_IP);
+	for (src_idx = 0; src_idx < nsrcs; src_idx++) {
+		src_ip.u.ip4 = srcs[src_idx];
+		ent = br_multicast_find_group_src(pg, &src_ip);
+		if (!ent) {
+			ent = br_multicast_new_group_src(pg, &src_ip);
+			if (ent)
+				changed = true;
+		}
+
+		if (ent)
+			mod_timer(&ent->timer, now + br_multicast_gmi(br));
+	}
+
+	return changed;
+}
+
+static struct net_bridge_port_group *
+br_multicast_find_port(struct net_bridge_mdb_entry *mp,
+		       struct net_bridge_port *p,
+		       const unsigned char *src)
+{
+	struct net_bridge_port_group *pg;
+	struct net_bridge *br = mp->br;
+
+	for (pg = mlock_dereference(mp->ports, br);
+	     pg;
+	     pg = mlock_dereference(pg->next, br))
+		if (br_port_group_equal(pg, p, src))
+			return pg;
+
+	return NULL;
+}
+
 static int br_ip4_multicast_igmp3_report(struct net_bridge *br,
 					 struct net_bridge_port *port,
 					 struct sk_buff *skb,
 					 u16 vid)
 {
+	bool igmpv2 = br->multicast_igmp_version == 2;
+	struct net_bridge_mdb_entry *mdst;
+	struct net_bridge_port_group *pg;
 	const unsigned char *src;
 	struct igmpv3_report *ih;
 	struct igmpv3_grec *grec;
-	int i;
-	int len;
-	int num;
-	int type;
-	int err = 0;
+	int i, len, num, type;
+	bool changed = false;
 	__be32 group;
+	int err = 0;
 	u16 nsrcs;
 
 	ih = igmpv3_report_hdr(skb);
@@ -1187,7 +1241,6 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br,
 		if (!ip_mc_may_pull(skb, len))
 			return -EINVAL;
 
-		/* We treat this as an IGMPv2 report for now. */
 		switch (type) {
 		case IGMPV3_MODE_IS_INCLUDE:
 		case IGMPV3_MODE_IS_EXCLUDE:
@@ -1202,16 +1255,41 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br,
 		}
 
 		src = eth_hdr(skb)->h_source;
-		if ((type == IGMPV3_CHANGE_TO_INCLUDE ||
-		     type == IGMPV3_MODE_IS_INCLUDE) &&
-		    nsrcs == 0) {
-			br_ip4_multicast_leave_group(br, port, group, vid, src);
+		if (nsrcs == 0 &&
+		    (type == IGMPV3_CHANGE_TO_INCLUDE ||
+		     type == IGMPV3_MODE_IS_INCLUDE)) {
+			if (igmpv2 || !port) {
+				br_ip4_multicast_leave_group(br, port, group, vid, src);
+				continue;
+			}
 		} else {
 			err = br_ip4_multicast_add_group(br, port, group, vid,
-							 src);
+							 src, igmpv2);
 			if (err)
 				break;
 		}
+
+		if (!port || igmpv2)
+			continue;
+
+		spin_lock_bh(&br->multicast_lock);
+		mdst = br_mdb_ip4_get(br, group, vid);
+		if (!mdst)
+			goto unlock_continue;
+		pg = br_multicast_find_port(mdst, port, src);
+		if (!pg || (pg->flags & MDB_PG_FLAGS_PERMANENT))
+			goto unlock_continue;
+		/* reload grec */
+		grec = (void *)(skb->data + len - sizeof(*grec) - (nsrcs * 4));
+		switch (type) {
+		case IGMPV3_ALLOW_NEW_SOURCES:
+			changed = br_multicast_isinc_allow(pg, grec->grec_src, nsrcs);
+			break;
+		}
+		if (changed)
+			br_mdb_notify(br->dev, mdst, pg, RTM_NEWMDB);
+unlock_continue:
+		spin_unlock_bh(&br->multicast_lock);
 	}
 
 	return err;
@@ -1859,7 +1937,8 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
 	case IGMP_HOST_MEMBERSHIP_REPORT:
 	case IGMPV2_HOST_MEMBERSHIP_REPORT:
 		BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
-		err = br_ip4_multicast_add_group(br, port, ih->group, vid, src);
+		err = br_ip4_multicast_add_group(br, port, ih->group, vid, src,
+						 true);
 		break;
 	case IGMPV3_HOST_MEMBERSHIP_REPORT:
 		err = br_ip4_multicast_igmp3_report(br, port, skb, vid);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index f514b45b2963..cbcec3bf28ea 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -874,6 +874,13 @@ static inline unsigned long br_multicast_lmqt(const struct net_bridge *br)
 	return br->multicast_last_member_interval *
 	       br->multicast_last_member_count;
 }
+
+static inline unsigned long br_multicast_gmi(const struct net_bridge *br)
+{
+	/* use the RFC default of 2 for QRV */
+	return 2 * br->multicast_query_interval +
+	       br->multicast_query_response_interval;
+}
 #else
 static inline int br_multicast_rcv(struct net_bridge *br,
 				   struct net_bridge_port *port,
-- 
2.25.4