net: bridge: mcast: add support for src list and filter mode dumping

Support per port group src list (address and timer) and filter mode
dumping. Protected by either multicast_lock or rcu.

v3: add IPv6 support
v2: require RCU or multicast_lock to traverse src groups
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/uapi/linux/if_bridge.h

@@ -455,10 +455,31 @@ enum {
 enum {
 	MDBA_MDB_EATTR_UNSPEC,
 	MDBA_MDB_EATTR_TIMER,
+	MDBA_MDB_EATTR_SRC_LIST,
+	MDBA_MDB_EATTR_GROUP_MODE,
 	__MDBA_MDB_EATTR_MAX
 };
 #define MDBA_MDB_EATTR_MAX (__MDBA_MDB_EATTR_MAX - 1)
 
+/* per mdb entry source */
+enum {
+	MDBA_MDB_SRCLIST_UNSPEC,
+	MDBA_MDB_SRCLIST_ENTRY,
+	__MDBA_MDB_SRCLIST_MAX
+};
+#define MDBA_MDB_SRCLIST_MAX (__MDBA_MDB_SRCLIST_MAX - 1)
+
+/* per mdb entry per source attributes
+ * these are embedded in MDBA_MDB_SRCLIST_ENTRY
+ */
+enum {
+	MDBA_MDB_SRCATTR_UNSPEC,
+	MDBA_MDB_SRCATTR_ADDRESS,
+	MDBA_MDB_SRCATTR_TIMER,
+	__MDBA_MDB_SRCATTR_MAX
+};
+#define MDBA_MDB_SRCATTR_MAX (__MDBA_MDB_SRCATTR_MAX - 1)
+
 /* multicast router types */
 enum {
 	MDB_RTR_TYPE_DISABLED,

net/bridge/br_mdb.c

@@ -77,10 +77,67 @@ static void __mdb_entry_to_br_ip(struct br_mdb_entry *entry, struct br_ip *ip)
 #endif
 }
 
+static int __mdb_fill_srcs(struct sk_buff *skb,
+			   struct net_bridge_port_group *p)
+{
+	struct net_bridge_group_src *ent;
+	struct nlattr *nest, *nest_ent;
+
+	if (hlist_empty(&p->src_list))
+		return 0;
+
+	nest = nla_nest_start(skb, MDBA_MDB_EATTR_SRC_LIST);
+	if (!nest)
+		return -EMSGSIZE;
+
+	hlist_for_each_entry_rcu(ent, &p->src_list, node,
+				 lockdep_is_held(&p->port->br->multicast_lock)) {
+		nest_ent = nla_nest_start(skb, MDBA_MDB_SRCLIST_ENTRY);
+		if (!nest_ent)
+			goto out_cancel_err;
+		switch (ent->addr.proto) {
+		case htons(ETH_P_IP):
+			if (nla_put_in_addr(skb, MDBA_MDB_SRCATTR_ADDRESS,
+					    ent->addr.u.ip4)) {
+				nla_nest_cancel(skb, nest_ent);
+				goto out_cancel_err;
+			}
+			break;
+#if IS_ENABLED(CONFIG_IPV6)
+		case htons(ETH_P_IPV6):
+			if (nla_put_in6_addr(skb, MDBA_MDB_SRCATTR_ADDRESS,
+					     &ent->addr.u.ip6)) {
+				nla_nest_cancel(skb, nest_ent);
+				goto out_cancel_err;
+			}
+			break;
+#endif
+		default:
+			nla_nest_cancel(skb, nest_ent);
+			continue;
+		}
+		if (nla_put_u32(skb, MDBA_MDB_SRCATTR_TIMER,
+				br_timer_value(&ent->timer))) {
+			nla_nest_cancel(skb, nest_ent);
+			goto out_cancel_err;
+		}
+		nla_nest_end(skb, nest_ent);
+	}
+
+	nla_nest_end(skb, nest);
+
+	return 0;
+
+out_cancel_err:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
 static int __mdb_fill_info(struct sk_buff *skb,
 			   struct net_bridge_mdb_entry *mp,
 			   struct net_bridge_port_group *p)
 {
+	bool dump_srcs_mode = false;
 	struct timer_list *mtimer;
 	struct nlattr *nest_ent;
 	struct br_mdb_entry e;
@@ -119,6 +176,23 @@ static int __mdb_fill_info(struct sk_buff *skb,
 		nla_nest_cancel(skb, nest_ent);
 		return -EMSGSIZE;
 	}
+	switch (mp->addr.proto) {
+	case htons(ETH_P_IP):
+		dump_srcs_mode = !!(p && mp->br->multicast_igmp_version == 3);
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case htons(ETH_P_IPV6):
+		dump_srcs_mode = !!(p && mp->br->multicast_mld_version == 2);
+		break;
+#endif
+	}
+	if (dump_srcs_mode &&
+	    (__mdb_fill_srcs(skb, p) ||
+	     nla_put_u8(skb, MDBA_MDB_EATTR_GROUP_MODE, p->filter_mode))) {
+		nla_nest_cancel(skb, nest_ent);
+		return -EMSGSIZE;
+	}
+
 	nla_nest_end(skb, nest_ent);
 
 	return 0;
@@ -127,7 +201,7 @@ static int __mdb_fill_info(struct sk_buff *skb,
 static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 			    struct net_device *dev)
 {
-	int idx = 0, s_idx = cb->args[1], err = 0;
+	int idx = 0, s_idx = cb->args[1], err = 0, pidx = 0, s_pidx = cb->args[2];
 	struct net_bridge *br = netdev_priv(dev);
 	struct net_bridge_mdb_entry *mp;
 	struct nlattr *nest, *nest2;
@@ -152,7 +226,7 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 			break;
 		}
 
-		if (mp->host_joined) {
+		if (!s_pidx && mp->host_joined) {
 			err = __mdb_fill_info(skb, mp, NULL);
 			if (err) {
 				nla_nest_cancel(skb, nest2);
@@ -164,13 +238,19 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 		      pp = &p->next) {
 			if (!p->port)
 				continue;
+			if (pidx < s_pidx)
+				goto skip_pg;
 
 			err = __mdb_fill_info(skb, mp, p);
 			if (err) {
 				nla_nest_cancel(skb, nest2);
 				goto out;
 			}
+skip_pg:
+			pidx++;
 		}
+		pidx = 0;
+		s_pidx = 0;
 		nla_nest_end(skb, nest2);
 skip:
 		idx++;
@@ -178,6 +258,7 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
 
 out:
 	cb->args[1] = idx;
+	cb->args[2] = pidx;
 	nla_nest_end(skb, nest);
 	return err;
 }