bridge: mcast: add MLDv2 querier support

This patch adds basic support for MLDv2 queries, the default is MLDv1
as before. A new multicast option - multicast_mld_version, adds the
ability to change it between 1 and 2 via netlink and sysfs.
The MLD option is disabled if CONFIG_IPV6 is disabled.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/if_link.h

@@ -276,6 +276,7 @@ enum {
 	IFLA_BR_VLAN_STATS_ENABLED,
 	IFLA_BR_MCAST_STATS_ENABLED,
 	IFLA_BR_MCAST_IGMP_VERSION,
+	IFLA_BR_MCAST_MLD_VERSION,
 	__IFLA_BR_MAX,
 };
 

net/bridge/br_multicast.c

@@ -459,15 +459,20 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 						    const struct in6_addr *grp,
 						    u8 *igmp_type)
 {
-	struct sk_buff *skb;
+	struct mld2_query *mld2q;
+	unsigned long interval;
 	struct ipv6hdr *ip6h;
 	struct mld_msg *mldq;
+	size_t mld_hdr_size;
+	struct sk_buff *skb;
 	struct ethhdr *eth;
 	u8 *hopopt;
-	unsigned long interval;
 
+	mld_hdr_size = sizeof(*mldq);
+	if (br->multicast_mld_version == 2)
+		mld_hdr_size = sizeof(*mld2q);
 	skb = netdev_alloc_skb_ip_align(br->dev, sizeof(*eth) + sizeof(*ip6h) +
-						 8 + sizeof(*mldq));
+						 8 + mld_hdr_size);
 	if (!skb)
 		goto out;
 
@@ -486,7 +491,7 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 	ip6h = ipv6_hdr(skb);
 
 	*(__force __be32 *)ip6h = htonl(0x60000000);
-	ip6h->payload_len = htons(8 + sizeof(*mldq));
+	ip6h->payload_len = htons(8 + mld_hdr_size);
 	ip6h->nexthdr = IPPROTO_HOPOPTS;
 	ip6h->hop_limit = 1;
 	ipv6_addr_set(&ip6h->daddr, htonl(0xff020000), 0, 0, htonl(1));
@@ -514,26 +519,47 @@ static struct sk_buff *br_ip6_multicast_alloc_query(struct net_bridge *br,
 
 	/* ICMPv6 */
 	skb_set_transport_header(skb, skb->len);
-	mldq = (struct mld_msg *) icmp6_hdr(skb);
-
 	interval = ipv6_addr_any(grp) ?
 			br->multicast_query_response_interval :
 			br->multicast_last_member_interval;
-
 	*igmp_type = ICMPV6_MGM_QUERY;
-	mldq->mld_type = ICMPV6_MGM_QUERY;
-	mldq->mld_code = 0;
-	mldq->mld_cksum = 0;
-	mldq->mld_maxdelay = htons((u16)jiffies_to_msecs(interval));
-	mldq->mld_reserved = 0;
-	mldq->mld_mca = *grp;
-
-	/* checksum */
-	mldq->mld_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
-					  sizeof(*mldq), IPPROTO_ICMPV6,
-					  csum_partial(mldq,
-						       sizeof(*mldq), 0));
-	skb_put(skb, sizeof(*mldq));
+	switch (br->multicast_mld_version) {
+	case 1:
+		mldq = (struct mld_msg *)icmp6_hdr(skb);
+		mldq->mld_type = ICMPV6_MGM_QUERY;
+		mldq->mld_code = 0;
+		mldq->mld_cksum = 0;
+		mldq->mld_maxdelay = htons((u16)jiffies_to_msecs(interval));
+		mldq->mld_reserved = 0;
+		mldq->mld_mca = *grp;
+		mldq->mld_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+						  sizeof(*mldq), IPPROTO_ICMPV6,
+						  csum_partial(mldq,
+							       sizeof(*mldq),
+							       0));
+		break;
+	case 2:
+		mld2q = (struct mld2_query *)icmp6_hdr(skb);
+		mld2q->mld2q_mrc = ntohs((u16)jiffies_to_msecs(interval));
+		mld2q->mld2q_type = ICMPV6_MGM_QUERY;
+		mld2q->mld2q_code = 0;
+		mld2q->mld2q_cksum = 0;
+		mld2q->mld2q_resv1 = 0;
+		mld2q->mld2q_resv2 = 0;
+		mld2q->mld2q_suppress = 0;
+		mld2q->mld2q_qrv = 2;
+		mld2q->mld2q_nsrcs = 0;
+		mld2q->mld2q_qqic = br->multicast_query_interval / HZ;
+		mld2q->mld2q_mca = *grp;
+		mld2q->mld2q_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+						     sizeof(*mld2q),
+						     IPPROTO_ICMPV6,
+						     csum_partial(mld2q,
+								  sizeof(*mld2q),
+								  0));
+		break;
+	}
+	skb_put(skb, mld_hdr_size);
 
 	__skb_pull(skb, sizeof(*eth));
 
@@ -1842,7 +1868,6 @@ void br_multicast_init(struct net_bridge *br)
 	br->hash_elasticity = 4;
 	br->hash_max = 512;
 
-	br->multicast_igmp_version = 2;
 	br->multicast_router = MDB_RTR_TYPE_TEMP_QUERY;
 	br->multicast_querier = 0;
 	br->multicast_query_use_ifaddr = 0;
@@ -1858,7 +1883,9 @@ void br_multicast_init(struct net_bridge *br)
 
 	br->ip4_other_query.delay_time = 0;
 	br->ip4_querier.port = NULL;
+	br->multicast_igmp_version = 2;
 #if IS_ENABLED(CONFIG_IPV6)
+	br->multicast_mld_version = 1;
 	br->ip6_other_query.delay_time = 0;
 	br->ip6_querier.port = NULL;
 #endif
@@ -2177,6 +2204,26 @@ int br_multicast_set_igmp_version(struct net_bridge *br, unsigned long val)
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_IPV6)
+int br_multicast_set_mld_version(struct net_bridge *br, unsigned long val)
+{
+	/* Currently we support version 1 and 2 */
+	switch (val) {
+	case 1:
+	case 2:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	spin_lock_bh(&br->multicast_lock);
+	br->multicast_mld_version = val;
+	spin_unlock_bh(&br->multicast_lock);
+
+	return 0;
+}
+#endif
+
 /**
  * br_multicast_list_adjacent - Returns snooped multicast addresses
  * @dev:	The bridge port adjacent to which to retrieve addresses

net/bridge/br_netlink.c

@@ -859,6 +859,7 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = {
 	[IFLA_BR_VLAN_STATS_ENABLED] = { .type = NLA_U8 },
 	[IFLA_BR_MCAST_STATS_ENABLED] = { .type = NLA_U8 },
 	[IFLA_BR_MCAST_IGMP_VERSION] = { .type = NLA_U8 },
+	[IFLA_BR_MCAST_MLD_VERSION] = { .type = NLA_U8 },
 };
 
 static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1079,6 +1080,17 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 		if (err)
 			return err;
 	}
+
+#if IS_ENABLED(CONFIG_IPV6)
+	if (data[IFLA_BR_MCAST_MLD_VERSION]) {
+		__u8 mld_version;
+
+		mld_version = nla_get_u8(data[IFLA_BR_MCAST_MLD_VERSION]);
+		err = br_multicast_set_mld_version(br, mld_version);
+		if (err)
+			return err;
+	}
+#endif
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	if (data[IFLA_BR_NF_CALL_IPTABLES]) {
@@ -1146,6 +1158,7 @@ static size_t br_get_size(const struct net_device *brdev)
 	       nla_total_size_64bit(sizeof(u64)) + /* IFLA_BR_MCAST_QUERY_RESPONSE_INTVL */
 	       nla_total_size_64bit(sizeof(u64)) + /* IFLA_BR_MCAST_STARTUP_QUERY_INTVL */
 	       nla_total_size(sizeof(u8)) +	/* IFLA_BR_MCAST_IGMP_VERSION */
+	       nla_total_size(sizeof(u8)) +	/* IFLA_BR_MCAST_MLD_VERSION */
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_NF_CALL_IPTABLES */
@@ -1225,7 +1238,11 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev)
 	    nla_put_u8(skb, IFLA_BR_MCAST_IGMP_VERSION,
 		       br->multicast_igmp_version))
 		return -EMSGSIZE;
-
+#if IS_ENABLED(CONFIG_IPV6)
+	if (nla_put_u8(skb, IFLA_BR_MCAST_MLD_VERSION,
+		       br->multicast_mld_version))
+		return -EMSGSIZE;
+#endif
 	clockval = jiffies_to_clock_t(br->multicast_last_member_interval);
 	if (nla_put_u64_64bit(skb, IFLA_BR_MCAST_LAST_MEMBER_INTVL, clockval,
 			      IFLA_BR_PAD))

net/bridge/br_private.h

@@ -355,6 +355,7 @@ struct net_bridge
 	struct bridge_mcast_other_query	ip6_other_query;
 	struct bridge_mcast_own_query	ip6_own_query;
 	struct bridge_mcast_querier	ip6_querier;
+	u8				multicast_mld_version;
 #endif /* IS_ENABLED(CONFIG_IPV6) */
 #endif
 
@@ -585,6 +586,9 @@ int br_multicast_toggle(struct net_bridge *br, unsigned long val);
 int br_multicast_set_querier(struct net_bridge *br, unsigned long val);
 int br_multicast_set_hash_max(struct net_bridge *br, unsigned long val);
 int br_multicast_set_igmp_version(struct net_bridge *br, unsigned long val);
+#if IS_ENABLED(CONFIG_IPV6)
+int br_multicast_set_mld_version(struct net_bridge *br, unsigned long val);
+#endif
 struct net_bridge_mdb_entry *
 br_mdb_ip_get(struct net_bridge_mdb_htable *mdb, struct br_ip *dst);
 struct net_bridge_mdb_entry *

net/bridge/br_sysfs_br.c

@@ -659,6 +659,25 @@ static ssize_t multicast_stats_enabled_store(struct device *d,
 	return store_bridge_parm(d, buf, len, set_stats_enabled);
 }
 static DEVICE_ATTR_RW(multicast_stats_enabled);
+
+#if IS_ENABLED(CONFIG_IPV6)
+static ssize_t multicast_mld_version_show(struct device *d,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct net_bridge *br = to_bridge(d);
+
+	return sprintf(buf, "%u\n", br->multicast_mld_version);
+}
+
+static ssize_t multicast_mld_version_store(struct device *d,
+					   struct device_attribute *attr,
+					   const char *buf, size_t len)
+{
+	return store_bridge_parm(d, buf, len, br_multicast_set_mld_version);
+}
+static DEVICE_ATTR_RW(multicast_mld_version);
+#endif
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 static ssize_t nf_call_iptables_show(
@@ -827,6 +846,9 @@ static struct attribute *bridge_attrs[] = {
 	&dev_attr_multicast_startup_query_interval.attr,
 	&dev_attr_multicast_stats_enabled.attr,
 	&dev_attr_multicast_igmp_version.attr,
+#if IS_ENABLED(CONFIG_IPV6)
+	&dev_attr_multicast_mld_version.attr,
+#endif
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	&dev_attr_nf_call_iptables.attr,