[PATCH v4 0/2] batman-adv: routeable multicast preparations

[PATCH v4 0/2] batman-adv: routeable multicast preparations

[Linus Lüssing]

This patchset provides some code restructuring in preparation for the
support of routeable multicast addresses.

The first one swaps the kernel MAC multicast list with the equivalent
IPv4 and IPv6 ones: This allows an easier filtering later.

Patch 2 is a first application of such filtering and allows
omitting some redundant address additions to the TT. Later, the same
will be necessary for routeable multicast addresses.

---

Changelog v4:

* rebased to master:
  -> removed [PATCH v3 1/3] (now applied)
* fixed build issues with CONFIG_IPV6 disabled

Changelog v3:

* fixed "From:" address in mail header

Changelog v2:

* rebased to master
* removed already applied patch
  ("batman-adv: mcast: fix multicast tt/tvlv worker locking")
* split patchset in two with the intention to ease reviewing
  (no code changes, just omitted the last two patches)

* kerneldoc: alignment for batadv_mcast_mla_flags_update()
  [PATCH 2/6] / [PATCH v2 1/3]
* fixed compile issues due to a duplicated member in struct
* batadv_priv_mcast
  [PATCH 2/6] / [PATCH v2 1/3]
* kerneldoc: added missing @flags for batadv_mcast_mla_flags_update()
  [PATCH 2/6] / [PATCH v2 1/3]
* kerneldoc: @flags -> @tvlv_flags in struct batadv_mcast_mla_flags
  [PATCH 2/6] / [PATCH v2 1/3]

[PATCH v4 1/2] batman-adv: mcast: collect softif listeners from IP lists instead

[Linus Lüssing]

Instead of collecting multicast MAC addresses from the netdev hw mc
list collect a node's multicast listeners from the IP lists and convert
those to MAC addresses.

This allows to exclude addresses of specific scope later. On a
multicast MAC address the IP destination scope is not visible anymore.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 net/batman-adv/multicast.c | 258 +++++++++++++++++++++++++------------
 1 file changed, 173 insertions(+), 85 deletions(-)

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index af0e2ce8..693e3bba 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -20,6 +20,7 @@
 #include <linux/igmp.h>
 #include <linux/in.h>
 #include <linux/in6.h>
+#include <linux/inetdevice.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/jiffies.h>
@@ -171,91 +172,6 @@ static struct net_device *batadv_mcast_get_bridge(struct net_device *soft_iface)
 	return upper;
 }
 
-/**
- * batadv_mcast_addr_is_ipv4() - check if multicast MAC is IPv4
- * @addr: the MAC address to check
- *
- * Return: True, if MAC address is one reserved for IPv4 multicast, false
- * otherwise.
- */
-static bool batadv_mcast_addr_is_ipv4(const u8 *addr)
-{
-	static const u8 prefix[] = {0x01, 0x00, 0x5E};
-
-	return memcmp(prefix, addr, sizeof(prefix)) == 0;
-}
-
-/**
- * batadv_mcast_addr_is_ipv6() - check if multicast MAC is IPv6
- * @addr: the MAC address to check
- *
- * Return: True, if MAC address is one reserved for IPv6 multicast, false
- * otherwise.
- */
-static bool batadv_mcast_addr_is_ipv6(const u8 *addr)
-{
-	static const u8 prefix[] = {0x33, 0x33};
-
-	return memcmp(prefix, addr, sizeof(prefix)) == 0;
-}
-
-/**
- * batadv_mcast_mla_softif_get() - get softif multicast listeners
- * @dev: the device to collect multicast addresses from
- * @mcast_list: a list to put found addresses into
- * @flags: flags indicating the new multicast state
- *
- * Collects multicast addresses of multicast listeners residing
- * on this kernel on the given soft interface, dev, in
- * the given mcast_list. In general, multicast listeners provided by
- * your multicast receiving applications run directly on this node.
- *
- * If there is a bridge interface on top of dev, collects from that one
- * instead. Just like with IP addresses and routes, multicast listeners
- * will(/should) register to the bridge interface instead of an
- * enslaved bat0.
- *
- * Return: -ENOMEM on memory allocation error or the number of
- * items added to the mcast_list otherwise.
- */
-static int
-batadv_mcast_mla_softif_get(struct net_device *dev,
-			    struct hlist_head *mcast_list,
-			    struct batadv_mcast_mla_flags *flags)
-{
-	bool all_ipv4 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4;
-	bool all_ipv6 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6;
-	struct net_device *bridge = batadv_mcast_get_bridge(dev);
-	struct netdev_hw_addr *mc_list_entry;
-	struct batadv_hw_addr *new;
-	int ret = 0;
-
-	netif_addr_lock_bh(bridge ? bridge : dev);
-	netdev_for_each_mc_addr(mc_list_entry, bridge ? bridge : dev) {
-		if (all_ipv4 && batadv_mcast_addr_is_ipv4(mc_list_entry->addr))
-			continue;
-
-		if (all_ipv6 && batadv_mcast_addr_is_ipv6(mc_list_entry->addr))
-			continue;
-
-		new = kmalloc(sizeof(*new), GFP_ATOMIC);
-		if (!new) {
-			ret = -ENOMEM;
-			break;
-		}
-
-		ether_addr_copy(new->addr, mc_list_entry->addr);
-		hlist_add_head(&new->list, mcast_list);
-		ret++;
-	}
-	netif_addr_unlock_bh(bridge ? bridge : dev);
-
-	if (bridge)
-		dev_put(bridge);
-
-	return ret;
-}
-
 /**
  * batadv_mcast_mla_is_duplicate() - check whether an address is in a list
  * @mcast_addr: the multicast address to check
@@ -276,6 +192,178 @@ static bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,
 	return false;
 }
 
+/**
+ * batadv_mcast_mla_softif_get_ipv4() - get softif IPv4 multicast listeners
+ * @dev: the device to collect multicast addresses from
+ * @mcast_list: a list to put found addresses into
+ * @flags: flags indicating the new multicast state
+ *
+ * Collects multicast addresses of IPv4 multicast listeners residing
+ * on this kernel on the given soft interface, dev, in
+ * the given mcast_list. In general, multicast listeners provided by
+ * your multicast receiving applications run directly on this node.
+ *
+ * Return: -ENOMEM on memory allocation error or the number of
+ * items added to the mcast_list otherwise.
+ */
+static int
+batadv_mcast_mla_softif_get_ipv4(struct net_device *dev,
+				 struct hlist_head *mcast_list,
+				 struct batadv_mcast_mla_flags *flags)
+{
+	struct batadv_hw_addr *new;
+	struct in_device *in_dev;
+	u8 mcast_addr[ETH_ALEN];
+	struct ip_mc_list *pmc;
+	int ret = 0;
+
+	if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4)
+		return 0;
+
+	in_dev = in_dev_get(dev);
+	if (!in_dev)
+		return 0;
+
+	rcu_read_lock();
+	for (pmc = rcu_dereference(in_dev->mc_list); pmc;
+	     pmc = rcu_dereference(pmc->next_rcu)) {
+		ip_eth_mc_map(pmc->multiaddr, mcast_addr);
+
+		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
+			continue;
+
+		new = kmalloc(sizeof(*new), GFP_ATOMIC);
+		if (!new) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ether_addr_copy(new->addr, mcast_addr);
+		hlist_add_head(&new->list, mcast_list);
+		ret++;
+	}
+	rcu_read_unlock();
+	in_dev_put(in_dev);
+
+	return ret;
+}
+
+/**
+ * batadv_mcast_mla_softif_get_ipv6() - get softif IPv6 multicast listeners
+ * @dev: the device to collect multicast addresses from
+ * @mcast_list: a list to put found addresses into
+ * @flags: flags indicating the new multicast state
+ *
+ * Collects multicast addresses of IPv6 multicast listeners residing
+ * on this kernel on the given soft interface, dev, in
+ * the given mcast_list. In general, multicast listeners provided by
+ * your multicast receiving applications run directly on this node.
+ *
+ * Return: -ENOMEM on memory allocation error or the number of
+ * items added to the mcast_list otherwise.
+ */
+#if IS_ENABLED(CONFIG_IPV6)
+static int
+batadv_mcast_mla_softif_get_ipv6(struct net_device *dev,
+				 struct hlist_head *mcast_list,
+				 struct batadv_mcast_mla_flags *flags)
+{
+	struct batadv_hw_addr *new;
+	struct inet6_dev *in6_dev;
+	u8 mcast_addr[ETH_ALEN];
+	struct ifmcaddr6 *pmc6;
+	int ret = 0;
+
+	if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6)
+		return 0;
+
+	in6_dev = in6_dev_get(dev);
+	if (!in6_dev)
+		return 0;
+
+	read_lock_bh(&in6_dev->lock);
+	for (pmc6 = in6_dev->mc_list; pmc6; pmc6 = pmc6->next) {
+		if (IPV6_ADDR_MC_SCOPE(&pmc6->mca_addr) <
+		    IPV6_ADDR_SCOPE_LINKLOCAL)
+			continue;
+
+		ipv6_eth_mc_map(&pmc6->mca_addr, mcast_addr);
+
+		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
+			continue;
+
+		new = kmalloc(sizeof(*new), GFP_ATOMIC);
+		if (!new) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ether_addr_copy(new->addr, mcast_addr);
+		hlist_add_head(&new->list, mcast_list);
+		ret++;
+	}
+	read_unlock_bh(&in6_dev->lock);
+	in6_dev_put(in6_dev);
+
+	return ret;
+}
+#else
+static inline int
+batadv_mcast_mla_softif_get_ipv6(struct net_device *dev,
+				 struct hlist_head *mcast_list,
+				 struct batadv_mcast_mla_flags *flags)
+{
+	return 0;
+}
+#endif
+
+/**
+ * batadv_mcast_mla_softif_get() - get softif multicast listeners
+ * @dev: the device to collect multicast addresses from
+ * @mcast_list: a list to put found addresses into
+ * @flags: flags indicating the new multicast state
+ *
+ * Collects multicast addresses of multicast listeners residing
+ * on this kernel on the given soft interface, dev, in
+ * the given mcast_list. In general, multicast listeners provided by
+ * your multicast receiving applications run directly on this node.
+ *
+ * If there is a bridge interface on top of dev, collects from that one
+ * instead. Just like with IP addresses and routes, multicast listeners
+ * will(/should) register to the bridge interface instead of an
+ * enslaved bat0.
+ *
+ * Return: -ENOMEM on memory allocation error or the number of
+ * items added to the mcast_list otherwise.
+ */
+static int
+batadv_mcast_mla_softif_get(struct net_device *dev,
+			    struct hlist_head *mcast_list,
+			    struct batadv_mcast_mla_flags *flags)
+{
+	struct net_device *bridge = batadv_mcast_get_bridge(dev);
+	int ret4, ret6 = 0;
+
+	if (bridge)
+		dev = bridge;
+
+	ret4 = batadv_mcast_mla_softif_get_ipv4(dev, mcast_list, flags);
+	if (ret4 < 0)
+		goto out;
+
+	ret6 = batadv_mcast_mla_softif_get_ipv6(dev, mcast_list, flags);
+	if (ret6 < 0) {
+		ret4 = 0;
+		goto out;
+	}
+
+out:
+	if (bridge)
+		dev_put(bridge);
+
+	return ret4 + ret6;
+}
+
 /**
  * batadv_mcast_mla_br_addr_cpy() - copy a bridge multicast address
  * @dst: destination to write to - a multicast MAC address
-- 
2.20.1

[PATCH v4 2/2] batman-adv: mcast: avoid redundant multicast TT entries with bridges

[Linus Lüssing]

When a bridge is added on top of bat0 we set the WANT_ALL_UNSNOOPABLES
flag. Which means we sign up for all traffic for ff02::1/128 and
224.0.0.0/24.

When the node itself had IPv6 enabled or joined a group in 224.0.0.0/24
itself then so far this would result in a multicast TT entry which is
redundant to the WANT_ALL_UNSNOOPABLES.

With this patch such redundant TT entries are avoided.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 net/batman-adv/multicast.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 693e3bba..5940c2df 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -227,6 +227,10 @@ batadv_mcast_mla_softif_get_ipv4(struct net_device *dev,
 	rcu_read_lock();
 	for (pmc = rcu_dereference(in_dev->mc_list); pmc;
 	     pmc = rcu_dereference(pmc->next_rcu)) {
+		if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
+		    ipv4_is_local_multicast(pmc->multiaddr))
+			continue;
+
 		ip_eth_mc_map(pmc->multiaddr, mcast_addr);
 
 		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
@@ -287,6 +291,10 @@ batadv_mcast_mla_softif_get_ipv6(struct net_device *dev,
 		    IPV6_ADDR_SCOPE_LINKLOCAL)
 			continue;
 
+		if (flags->tvlv_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
+		    ipv6_addr_is_ll_all_nodes(&pmc6->mca_addr))
+			continue;
+
 		ipv6_eth_mc_map(&pmc6->mca_addr, mcast_addr);
 
 		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
@@ -407,9 +415,8 @@ static int batadv_mcast_mla_bridge_get(struct net_device *dev,
 				       struct batadv_mcast_mla_flags *flags)
 {
 	struct list_head bridge_mcast_list = LIST_HEAD_INIT(bridge_mcast_list);
-	bool all_ipv4 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4;
-	bool all_ipv6 = flags->tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6;
 	struct br_ip_list *br_ip_entry, *tmp;
+	u8 tvlv_flags = flags->tvlv_flags;
 	struct batadv_hw_addr *new;
 	u8 mcast_addr[ETH_ALEN];
 	int ret;
@@ -422,11 +429,25 @@ static int batadv_mcast_mla_bridge_get(struct net_device *dev,
 		goto out;
 
 	list_for_each_entry(br_ip_entry, &bridge_mcast_list, list) {
-		if (all_ipv4 && br_ip_entry->addr.proto == htons(ETH_P_IP))
-			continue;
+		if (br_ip_entry->addr.proto == htons(ETH_P_IP)) {
+			if (tvlv_flags & BATADV_MCAST_WANT_ALL_IPV4)
+				continue;
 
-		if (all_ipv6 && br_ip_entry->addr.proto == htons(ETH_P_IPV6))
-			continue;
+			if (tvlv_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
+			    ipv4_is_local_multicast(br_ip_entry->addr.u.ip4))
+				continue;
+		}
+
+#if IS_ENABLED(CONFIG_IPV6)
+		if (br_ip_entry->addr.proto == htons(ETH_P_IPV6)) {
+			if (tvlv_flags & BATADV_MCAST_WANT_ALL_IPV6)
+				continue;
+
+			if (tvlv_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
+			    ipv6_addr_is_ll_all_nodes(&br_ip_entry->addr.u.ip6))
+				continue;
+		}
+#endif
 
 		batadv_mcast_mla_br_addr_cpy(mcast_addr, &br_ip_entry->addr);
 		if (batadv_mcast_mla_is_duplicate(mcast_addr, mcast_list))
-- 
2.20.1