[B.A.T.M.A.N.] [PATCHv7 0/3] Multicast optimizations for bridges

[B.A.T.M.A.N.] [PATCHv7 0/3] Multicast optimizations for bridges

[Linus Lüssing]

This patchset enables the usage of the batman-adv multicast optimizations
for scenarios involving bridges on top of e.g. bat0, too.

Along come two more patches adding according debugging facilities
to make it possible for the user to check why the multicast
optimizations might not work ideally to give hints about
what they might change about their topology.

Cheers, Linus


Changes in v7 (thanks to Simon's suggestions):
- PATCH 2/3:
* renaming old/new_querier to old/new_state
* slightly extended kerneldoc of batadv_mcast_querier_log()
* removing words "good" and "bad" from debug output
* simplified batadv_mcast_flags_log()
* assignment instead of memset in batadv_mcast_mla_tvlv_update()
  and batadv_softif_init_late()
* simple struct member assignments instead of one complex struct
  assigment
* removing unnecessary memcmp's
* substituting return statement for an if-block in
  batadv_mcast_querier_log() and batadv_mcast_bridge_log()
* print "Unsnoopables(U)-flag" instead of just "U-flag"
- PATCH 3/3:
* use bat_priv values instead of querying bridge ABI in
  batadv_mcast_flags_print_header()

Changes in v6:
* New PATCH 2/3 inserted, moving logging to separate patch
* More verbose logging added to PATCH 2/3:
  Bridge and querier state changes are logged too
* upper case to lower case for kernel doc of batadv_mcast_flags_open
  (PATCH 2/3)
* Adding note to kernel doc of batadv_mcast_get_bridge about
  increased refcount (PATCH 1/3)
* Printing some lines about current bridge and querier state to
  debugfs too (PATCH 3/3)

Changes in v5 (PATCH 2/2 only):
* s/dat_cache/mcast_flags/ in kerneldoc (copy&paste error)

Changes in v4 (PATCH 2/2 only):
* initial {ad,e}dition of this patch

Changes in v3 (PATCH 1/2 only):
* Removed "RFC" tag in title again: The stubs and new export are upstream
  in net-next and therefore going to be included in 3.17
* Added some debug output:
  * Two warning messages:
    -> Old kernel version or no bridge IGMP/MLD snooping compiled
  * New batman-adv log-level "mcast":
    -> Logging mcast flag changes
  (a third debugging facility, a new table for debugfs for a global
   mcast flag overview will be added in a separate patch later
   as discussed with Simon)

Changes in v2 (PATCH 1/2 only):
* fetching local (= on this same kernel) multicast listeners from
  the bridge instead of the bat0 interface if a bridge is present
  - just like ip addresses and routes should be used from br0, the
  same goes for multicast listeners
* beautification of batadv_mcast_mla_br_addr_cpy(), now using already
  present functions from the kernel instead of own, hackish approach
* changed names of some goto-labels (not using "skip" anymore)
* using new, third bridge multicast export (because this export is
  not upstream yet, I've added the "RFC" in the title):
  br_multicast_has_querier_anywhere()
* adding compat stubs for two bridge multicast exports, to make
  batman-adv compile- and usable even if a 3.16 kernel was compiled
  without bridge code - the stubs are supposed to be upstream in the
  bridge code in 3.17 (therefore just 'compat')
* updated kerneldocs for batadv_mcast_mla_bridge_get() and
  batadv_mcast_mla_softif_get()
* The two sentences in the commit message starting with "Queriers: ..."
  were slightly modified to include the third bridge multicast export

[B.A.T.M.A.N.] [PATCHv7 1/3] batman-adv: Add multicast optimization support for bridged setups

[Linus Lüssing]

So far, the recently added multicast optimizations did not support
a configuration where a bridge is on top of the soft-interface (e.g.
bat0).

Now the Linux bridge code is able to provide us with the missing bits:

Multicast Listeners: The bridge hands us a list of multicast listeners
it has detected behind the bridge which we will announce through the
mesh via the translation table, allowing other nodes to direct multicast
packets to these clients behind the bridge even with enabled multicast
optimizations.

Queriers: The bridge informs us whether there is a selected IGMP or
MLD querier behind the bridge or if there is no querier at all. In these
cases we need all according IPv4 or IPv6 multicast traffic directed to us.

These two parts together allow us to serve all multicast listeners with
IPv6 link-local multicast packets even when bridges are involved and
our multicast optimizations enabled.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
 compat.c    |   39 ++++++++++++++
 compat.h    |   32 +++++++++++
 main.h      |    6 ++-
 multicast.c |  169 ++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 4 files changed, 227 insertions(+), 19 deletions(-)

diff --git a/compat.c b/compat.c
index 3dbf9d2..31546f5 100644
--- a/compat.c
+++ b/compat.c
@@ -109,3 +109,42 @@ void batadv_free_rcu_tvlv_handler(struct rcu_head *rcu)
 }
 
 #endif /* < KERNEL_VERSION(3, 0, 0) */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 16, 0)
+
+int br_multicast_list_adjacent(struct net_device *dev,
+			       struct list_head *br_ip_list)
+{
+	return 0;
+}
+
+bool br_multicast_has_querier_adjacent(struct net_device *dev, int proto)
+{
+	return false;
+}
+
+#endif /* < KERNEL_VERSION(3, 16, 0) */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
+
+bool br_multicast_has_querier_anywhere(struct net_device *dev, int proto)
+{
+	pr_warn_once("Old kernel detected (< 3.17) - multicast optimizations disabled\n");
+
+	return false;
+}
+
+#if !(IS_ENABLED(CONFIG_BRIDGE) && IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING))
+int br_multicast_list_adjacent(struct net_device *dev,
+			       struct list_head *br_ip_list)
+{
+	return 0;
+}
+
+bool br_multicast_has_querier_adjacent(struct net_device *dev, int proto)
+{
+	return false;
+}
+#endif
+
+#endif /* < KERNEL_VERSION(3, 17, 0) */
diff --git a/compat.h b/compat.h
index ed5b815..14de948 100644
--- a/compat.h
+++ b/compat.h
@@ -240,6 +240,12 @@ static inline void skb_reset_mac_len(struct sk_buff *skb)
 
 #endif /* < KERNEL_VERSION(3, 0, 0) */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 1, 0)
+
+#define IS_ENABLED(x) defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+
+#endif /* < KERNEL_VERSION(3, 1, 0) */
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 3, 0)
 
 #define batadv_interface_add_vid(x, y, z) \
@@ -444,6 +450,32 @@ static int __batadv_interface_kill_vid(struct net_device *dev, __be16 proto,\
 
 #define pskb_copy_for_clone pskb_copy
 
+int br_multicast_list_adjacent(struct net_device *dev,
+			       struct list_head *br_ip_list);
+bool br_multicast_has_querier_adjacent(struct net_device *dev, int proto);
+
+struct br_ip {
+	union {
+		__be32  ip4;
+#if IS_ENABLED(CONFIG_IPV6)
+		struct in6_addr ip6;
+#endif
+	} u;
+	__be16          proto;
+	__u16           vid;
+};
+
+struct br_ip_list {
+	struct list_head list;
+	struct br_ip addr;
+};
+
 #endif /* < KERNEL_VERSION(3, 16, 0) */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
+
+bool br_multicast_has_querier_anywhere(struct net_device *dev, int proto);
+
+#endif /* < KERNEL_VERSION(3, 17, 0) */
+
 #endif /* _NET_BATMAN_ADV_COMPAT_H_ */
diff --git a/main.h b/main.h
index fdfccff..acf9d84 100644
--- a/main.h
+++ b/main.h
@@ -169,6 +169,7 @@ enum batadv_uev_type {
 #include <linux/netdevice.h>	/* netdevice */
 #include <linux/etherdevice.h>  /* ethernet address classification */
 #include <linux/if_ether.h>	/* ethernet header */
+#include <linux/if_bridge.h>	/* bridge / multicast-snooping communication */
 #include <linux/poll.h>		/* poll_table */
 #include <linux/kthread.h>	/* kernel threads */
 #include <linux/pkt_sched.h>	/* schedule types */
@@ -177,6 +178,7 @@ enum batadv_uev_type {
 #include <linux/slab.h>
 #include <net/sock.h>		/* struct sock */
 #include <net/addrconf.h>	/* ipv6 address stuff */
+#include <net/ip.h>
 #include <linux/ip.h>
 #include <net/rtnetlink.h>
 #include <linux/jiffies.h>
@@ -223,6 +225,7 @@ __be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr);
  * @BATADV_DBG_BLA: bridge loop avoidance messages
  * @BATADV_DBG_DAT: ARP snooping and DAT related messages
  * @BATADV_DBG_NC: network coding related messages
+ * @BATADV_DBG_MCAST: multicast related messages
  * @BATADV_DBG_ALL: the union of all the above log levels
  */
 enum batadv_dbg_level {
@@ -232,7 +235,8 @@ enum batadv_dbg_level {
 	BATADV_DBG_BLA    = BIT(3),
 	BATADV_DBG_DAT    = BIT(4),
 	BATADV_DBG_NC	  = BIT(5),
-	BATADV_DBG_ALL    = 63,
+	BATADV_DBG_MCAST  = BIT(6),
+	BATADV_DBG_ALL    = 127,
 };
 
 #ifdef CONFIG_BATMAN_ADV_DEBUG
diff --git a/multicast.c b/multicast.c
index 96b66fd..c05f64a 100644
--- a/multicast.c
+++ b/multicast.c
@@ -23,12 +23,44 @@
 #include "multicast.h"
 
 /**
+ * batadv_mcast_get_bridge - get the bridge on top of the softif if it exists
+ * @soft_iface: netdev struct of the mesh interface
+ *
+ * Returns either a bridge interface on top of our soft interface or
+ * NULL if no such bridge exists.
+ *
+ * If found then the refcount of the bridge interface is incremented.
+ */
+static struct net_device *batadv_mcast_get_bridge(struct net_device *soft_iface)
+{
+	struct net_device *upper = soft_iface;
+
+	rcu_read_lock();
+	do {
+		upper = netdev_master_upper_dev_get_rcu(upper);
+	} while (upper && !(upper->priv_flags & IFF_EBRIDGE));
+
+	if (upper)
+		dev_hold(upper);
+	rcu_read_unlock();
+
+	return upper;
+}
+
+/**
  * 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
  *
- * Collect multicast addresses of the local multicast listeners
- * on the given soft interface, dev, in the given mcast_list.
+ * 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.
  *
  * Returns -ENOMEM on memory allocation error or the number of
  * items added to the mcast_list otherwise.
@@ -36,12 +68,13 @@
 static int batadv_mcast_mla_softif_get(struct net_device *dev,
 				       struct hlist_head *mcast_list)
 {
+	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(dev);
-	netdev_for_each_mc_addr(mc_list_entry, dev) {
+	netif_addr_lock_bh(bridge ? bridge : dev);
+	netdev_for_each_mc_addr(mc_list_entry, bridge ? bridge : dev) {
 		new = kmalloc(sizeof(*new), GFP_ATOMIC);
 		if (!new) {
 			ret = -ENOMEM;
@@ -52,7 +85,10 @@ static int batadv_mcast_mla_softif_get(struct net_device *dev,
 		hlist_add_head(&new->list, mcast_list);
 		ret++;
 	}
-	netif_addr_unlock_bh(dev);
+	netif_addr_unlock_bh(bridge ? bridge : dev);
+
+	if (bridge)
+		dev_put(bridge);
 
 	return ret;
 }
@@ -78,6 +114,83 @@ static bool batadv_mcast_mla_is_duplicate(uint8_t *mcast_addr,
 }
 
 /**
+ * batadv_mcast_mla_br_addr_cpy - copy a bridge multicast address
+ * @dst: destination to write to - a multicast MAC address
+ * @src: source to read from - a multicast IP address
+ *
+ * Converts a given multicast IPv4/IPv6 address from a bridge
+ * to its matching multicast MAC address and copies it into the given
+ * destination buffer.
+ *
+ * Caller needs to make sure the destination buffer can hold
+ * at least ETH_ALEN bytes.
+ */
+static void batadv_mcast_mla_br_addr_cpy(char *dst, const struct br_ip *src)
+{
+	if (src->proto == htons(ETH_P_IP))
+		ip_eth_mc_map(src->u.ip4, dst);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (src->proto == htons(ETH_P_IPV6))
+		ipv6_eth_mc_map(&src->u.ip6, dst);
+#endif
+	else
+		memset(dst, 0, ETH_ALEN);
+}
+
+/**
+ * batadv_mcast_mla_bridge_get - get bridged-in multicast listeners
+ * @dev: a bridge slave whose bridge to collect multicast addresses from
+ * @mcast_list: a list to put found addresses into
+ *
+ * Collects multicast addresses of multicast listeners residing
+ * on foreign, non-mesh devices which we gave access to our mesh via
+ * a bridge on top of the given soft interface, dev, in the given
+ * mcast_list.
+ *
+ * Returns -ENOMEM on memory allocation error or the number of
+ * items added to the mcast_list otherwise.
+ */
+static int batadv_mcast_mla_bridge_get(struct net_device *dev,
+				       struct hlist_head *mcast_list)
+{
+	struct list_head bridge_mcast_list = LIST_HEAD_INIT(bridge_mcast_list);
+	struct br_ip_list *br_ip_entry, *tmp;
+	struct batadv_hw_addr *new;
+	uint8_t mcast_addr[ETH_ALEN];
+	int ret;
+
+	/* we don't need to detect these devices/listeners, the IGMP/MLD
+	 * snooping code of the Linux bridge already does that for us
+	 */
+	ret = br_multicast_list_adjacent(dev, &bridge_mcast_list);
+	if (ret < 0)
+		goto out;
+
+	list_for_each_entry(br_ip_entry, &bridge_mcast_list, list) {
+		batadv_mcast_mla_br_addr_cpy(mcast_addr, &br_ip_entry->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);
+	}
+
+out:
+	list_for_each_entry_safe(br_ip_entry, tmp, &bridge_mcast_list, list) {
+		list_del(&br_ip_entry->list);
+		kfree(br_ip_entry);
+	}
+
+	return ret;
+}
+
+/**
  * batadv_mcast_mla_list_free - free a list of multicast addresses
  * @mcast_list: the list to free
  *
@@ -185,29 +298,44 @@ static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
  * Updates the own multicast tvlv with our current multicast related settings,
  * capabilities and inabilities.
  *
- * Returns true if the tvlv container is registered afterwards. Otherwise
- * returns false.
+ * Returns false if we want all IPv4 && IPv6 multicast traffic and true
+ * otherwise.
  */
 static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
 {
 	struct batadv_tvlv_mcast_data mcast_data;
+	struct net_device *dev = bat_priv->soft_iface;
 
 	mcast_data.flags = BATADV_NO_FLAGS;
 	memset(mcast_data.reserved, 0, sizeof(mcast_data.reserved));
 
-	/* Avoid attaching MLAs, if there is a bridge on top of our soft
-	 * interface, we don't support that yet (TODO)
+	if (!batadv_mcast_has_bridge(bat_priv))
+		goto update;
+
+#if !IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING)
+	pr_warn_once("No bridge IGMP snooping compiled - multicast optimizations disabled\n");
+#endif
+
+	mcast_data.flags |= BATADV_MCAST_WANT_ALL_UNSNOOPABLES;
+
+	/* 1) If no querier exists at all, then multicast listeners on
+	 *    our local TT clients behind the bridge will keep silent.
+	 * 2) If the selected querier is on one of our local TT clients,
+	 *    behind the bridge, then this querier might shadow multicast
+	 *    listeners on our local TT clients, behind this bridge.
+	 *
+	 * In both cases, we will signalize other batman nodes that
+	 * we need all multicast traffic of the according protocol.
 	 */
-	if (batadv_mcast_has_bridge(bat_priv)) {
-		if (bat_priv->mcast.enabled) {
-			batadv_tvlv_container_unregister(bat_priv,
-							 BATADV_TVLV_MCAST, 1);
-			bat_priv->mcast.enabled = false;
-		}
+	if (!br_multicast_has_querier_anywhere(dev, ETH_P_IP) ||
+	    br_multicast_has_querier_adjacent(dev, ETH_P_IP))
+		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV4;
 
-		return false;
-	}
+	if (!br_multicast_has_querier_anywhere(dev, ETH_P_IPV6) ||
+	    br_multicast_has_querier_adjacent(dev, ETH_P_IPV6))
+		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV6;
 
+update:
 	if (!bat_priv->mcast.enabled ||
 	    mcast_data.flags != bat_priv->mcast.flags) {
 		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 1,
@@ -216,7 +344,8 @@ static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
 		bat_priv->mcast.enabled = true;
 	}
 
-	return true;
+	return !(mcast_data.flags &
+		 (BATADV_MCAST_WANT_ALL_IPV4 + BATADV_MCAST_WANT_ALL_IPV6));
 }
 
 /**
@@ -239,6 +368,10 @@ void batadv_mcast_mla_update(struct batadv_priv *bat_priv)
 	if (ret < 0)
 		goto out;
 
+	ret = batadv_mcast_mla_bridge_get(soft_iface, &mcast_list);
+	if (ret < 0)
+		goto out;
+
 update:
 	batadv_mcast_mla_tt_retract(bat_priv, &mcast_list);
 	batadv_mcast_mla_tt_add(bat_priv, &mcast_list);
-- 
1.7.10.4

[B.A.T.M.A.N.] [PATCHv7 2/3] batman-adv: Adding 'mcast' log level

[Linus Lüssing]

This patch adds an 'mcast' log level. Currently, it will print changes
relevant to a nodes own multicast flag changes.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
 multicast.c      |  138 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
 soft-interface.c |    5 ++
 types.h          |   17 +++++++
 3 files changed, 155 insertions(+), 5 deletions(-)

diff --git a/multicast.c b/multicast.c
index c05f64a..915582d 100644
--- a/multicast.c
+++ b/multicast.c
@@ -292,6 +292,119 @@ static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
 }
 
 /**
+ * batadv_mcast_querier_log - debug output regarding the querier status on link
+ * @bat_priv: the bat priv with all the soft interface information
+ * @str_proto: a string for the querier protocol (e.g. "IGMP" or "MLD")
+ * @old_state: the previous querier state on our link
+ * @new_state: the new querier state on our link
+ *
+ * Outputs debug messages to the logging facility with log level 'mcast'
+ * regarding changes to the querier status on the link which are relevant
+ * to our multicast optimizations.
+ *
+ * Usually this is about whether a querier appeared or vanished in
+ * our mesh or whether the querier is in the suboptimal position of being
+ * behind our local bridge segment: Snooping switches will directly
+ * forward listener reports to the querier, therefore batman-adv and
+ * the bridge will potentially not see these listeners - the querier is
+ * potentially shadowing listeners from us then.
+ *
+ * This is only interesting for nodes with a bridge on top of their
+ * soft interface.
+ */
+static void
+batadv_mcast_querier_log(struct batadv_priv *bat_priv, char *str_proto,
+			 struct batadv_mcast_querier_state *old_state,
+			 struct batadv_mcast_querier_state *new_state)
+{
+	if (!old_state->exists && new_state->exists)
+		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+			   "%s Querier appeared\n", str_proto);
+	else if (old_state->exists && !new_state->exists)
+		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+			   "%s Querier disappeared\n", str_proto);
+	else if (!bat_priv->mcast.bridged && !new_state->exists)
+		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+			   "Note: No %s Querier present\n", str_proto);
+
+	if (new_state->exists) {
+		if (!old_state->shadowing && new_state->shadowing)
+			batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+				   "%s Querier is behind our bridged segment: Might shadow listeners\n",
+				   str_proto);
+		else if (old_state->shadowing && !new_state->shadowing)
+			batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+				   "%s Querier is not behind our bridged segment\n",
+				   str_proto);
+	}
+}
+
+/**
+ * batadv_mcast_bridge_log - debug output for topology changes in bridged setups
+ * @bat_priv: the bat priv with all the soft interface information
+ * @bridged: a flag about whether the soft interface is currently bridged or not
+ * @querier_ipv4: (maybe) new status of a potential, selected IGMP querier
+ * @querier_ipv6: (maybe) new status of a potential, selected MLD querier
+ *
+ * If no bridges are ever used on this node, then this function does nothing.
+ *
+ * Otherwise this function outputs debug information to the 'mcast' log level
+ * which might be relevant to our multicast optimizations.
+ *
+ * More precisely, it outputs information when a bridge interface is added or
+ * removed from a soft interface. And when a bridge is present, it further
+ * outputs information about the querier state which is relevant for the
+ * multicast flags this node is going to set.
+ */
+static void
+batadv_mcast_bridge_log(struct batadv_priv *bat_priv, bool bridged,
+			struct batadv_mcast_querier_state *querier_ipv4,
+			struct batadv_mcast_querier_state *querier_ipv6)
+{
+	if (!bat_priv->mcast.bridged && bridged)
+		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+			   "Bridge added: Setting Unsnoopables(U)-flag\n");
+	else if (bat_priv->mcast.bridged && !bridged)
+		batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+			   "Bridge removed: Unsetting Unsnoopables(U)-flag\n");
+
+	if (bridged) {
+		batadv_mcast_querier_log(bat_priv, "IGMP",
+					 &bat_priv->mcast.querier_ipv4,
+					 querier_ipv4);
+		batadv_mcast_querier_log(bat_priv, "MLD",
+					 &bat_priv->mcast.querier_ipv6,
+					 querier_ipv6);
+	}
+}
+
+/**
+ * batadv_mcast_flags_logs - output debug information about mcast flag changes
+ * @bat_priv: the bat priv with all the soft interface information
+ * @mcast_flags: flags indicating the new multicast state
+ *
+ * Whenever the multicast flags this nodes announces changes (@mcast_flags vs.
+ * bat_priv->mcast.flags), this notifies userspace via the 'mcast' log level.
+ */
+static void batadv_mcast_flags_log(struct batadv_priv *bat_priv, uint8_t flags)
+{
+	uint8_t old_flags = bat_priv->mcast.flags;
+	char str_old_flags[] = "[...]";
+
+	sprintf(str_old_flags, "[%c%c%c]",
+		old_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES ? 'U' : '.',
+		old_flags & BATADV_MCAST_WANT_ALL_IPV4 ? '4' : '.',
+		old_flags & BATADV_MCAST_WANT_ALL_IPV6 ? '6' : '.');
+
+	batadv_dbg(BATADV_DBG_MCAST, bat_priv,
+		   "Changing multicast flags from '%s' to '[%c%c%c]'\n",
+		   bat_priv->mcast.enabled ? str_old_flags : "<undefined>",
+		   flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES ? 'U' : '.',
+		   flags & BATADV_MCAST_WANT_ALL_IPV4 ? '4' : '.',
+		   flags & BATADV_MCAST_WANT_ALL_IPV6 ? '6' : '.');
+}
+
+/**
  * batadv_mcast_mla_tvlv_update - update multicast tvlv
  * @bat_priv: the bat priv with all the soft interface information
  *
@@ -304,18 +417,28 @@ static bool batadv_mcast_has_bridge(struct batadv_priv *bat_priv)
 static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
 {
 	struct batadv_tvlv_mcast_data mcast_data;
+	struct batadv_mcast_querier_state querier4 = {false, false};
+	struct batadv_mcast_querier_state querier6 = {false, false};
 	struct net_device *dev = bat_priv->soft_iface;
+	bool bridged;
 
 	mcast_data.flags = BATADV_NO_FLAGS;
 	memset(mcast_data.reserved, 0, sizeof(mcast_data.reserved));
 
-	if (!batadv_mcast_has_bridge(bat_priv))
+	bridged = batadv_mcast_has_bridge(bat_priv);
+	if (!bridged)
 		goto update;
 
 #if !IS_ENABLED(CONFIG_BRIDGE_IGMP_SNOOPING)
 	pr_warn_once("No bridge IGMP snooping compiled - multicast optimizations disabled\n");
 #endif
 
+	querier4.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IP);
+	querier4.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IP);
+
+	querier6.exists = br_multicast_has_querier_anywhere(dev, ETH_P_IPV6);
+	querier6.shadowing = br_multicast_has_querier_adjacent(dev, ETH_P_IPV6);
+
 	mcast_data.flags |= BATADV_MCAST_WANT_ALL_UNSNOOPABLES;
 
 	/* 1) If no querier exists at all, then multicast listeners on
@@ -327,21 +450,26 @@ static bool batadv_mcast_mla_tvlv_update(struct batadv_priv *bat_priv)
 	 * In both cases, we will signalize other batman nodes that
 	 * we need all multicast traffic of the according protocol.
 	 */
-	if (!br_multicast_has_querier_anywhere(dev, ETH_P_IP) ||
-	    br_multicast_has_querier_adjacent(dev, ETH_P_IP))
+	if (!querier4.exists || querier4.shadowing)
 		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV4;
 
-	if (!br_multicast_has_querier_anywhere(dev, ETH_P_IPV6) ||
-	    br_multicast_has_querier_adjacent(dev, ETH_P_IPV6))
+	if (!querier6.exists || querier6.shadowing)
 		mcast_data.flags |= BATADV_MCAST_WANT_ALL_IPV6;
 
 update:
+	batadv_mcast_bridge_log(bat_priv, bridged, &querier4, &querier6);
+
+	bat_priv->mcast.querier_ipv4 = querier4;
+	bat_priv->mcast.querier_ipv6 = querier6;
+
 	if (!bat_priv->mcast.enabled ||
 	    mcast_data.flags != bat_priv->mcast.flags) {
+		batadv_mcast_flags_log(bat_priv, mcast_data.flags);
 		batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 1,
 					       &mcast_data, sizeof(mcast_data));
 		bat_priv->mcast.flags = mcast_data.flags;
 		bat_priv->mcast.enabled = true;
+		bat_priv->mcast.bridged = bridged;
 	}
 
 	return !(mcast_data.flags &
diff --git a/soft-interface.c b/soft-interface.c
index 9bf382d..d4d892c 100644
--- a/soft-interface.c
+++ b/soft-interface.c
@@ -745,7 +745,12 @@ static int batadv_softif_init_late(struct net_device *dev)
 	atomic_set(&bat_priv->distributed_arp_table, 1);
 #endif
 #ifdef CONFIG_BATMAN_ADV_MCAST
+	bat_priv->mcast.querier_ipv4.exists = false;
+	bat_priv->mcast.querier_ipv4.shadowing = false;
+	bat_priv->mcast.querier_ipv6.exists = false;
+	bat_priv->mcast.querier_ipv6.shadowing = false;
 	bat_priv->mcast.flags = BATADV_NO_FLAGS;
+	bat_priv->mcast.bridged = false;
 	atomic_set(&bat_priv->multicast_mode, 1);
 	atomic_set(&bat_priv->mcast.num_disabled, 0);
 	atomic_set(&bat_priv->mcast.num_want_all_unsnoopables, 0);
diff --git a/types.h b/types.h
index 8854c05..b27c79d 100644
--- a/types.h
+++ b/types.h
@@ -625,14 +625,28 @@ struct batadv_priv_dat {
 
 #ifdef CONFIG_BATMAN_ADV_MCAST
 /**
+ * struct batadv_mcast_querier_state - IGMP/MLD querier state when bridged
+ * @exists: whether a querier exists in the mesh
+ * @shadowing: if a querier exists, whether it is potentially shadowing
+ *  multicast listeners (i.e. querier is behind our own bridge segment)
+ */
+struct batadv_mcast_querier_state {
+	bool exists;
+	bool shadowing;
+};
+
+/**
  * struct batadv_priv_mcast - per mesh interface mcast data
  * @mla_list: list of multicast addresses we are currently announcing via TT
  * @want_all_unsnoopables_list: a list of orig_nodes wanting all unsnoopable
  *  multicast traffic
  * @want_all_ipv4_list: a list of orig_nodes wanting all IPv4 multicast traffic
  * @want_all_ipv6_list: a list of orig_nodes wanting all IPv6 multicast traffic
+ * @querier_ipv4: the current state of an IGMP querier in the mesh (if bridged)
+ * @querier_ipv6: the current state of an MLD querier in the mesh (if bridged)
  * @flags: the flags we have last sent in our mcast tvlv
  * @enabled: whether the multicast tvlv is currently enabled
+ * @bridged: whether the soft interface currently has a bridge on top
  * @num_disabled: number of nodes that have no mcast tvlv
  * @num_want_all_unsnoopables: number of nodes wanting unsnoopable IP traffic
  * @num_want_all_ipv4: counter for items in want_all_ipv4_list
@@ -645,8 +659,11 @@ struct batadv_priv_mcast {
 	struct hlist_head want_all_unsnoopables_list;
 	struct hlist_head want_all_ipv4_list;
 	struct hlist_head want_all_ipv6_list;
+	struct batadv_mcast_querier_state querier_ipv4;
+	struct batadv_mcast_querier_state querier_ipv6;
 	uint8_t flags;
 	bool enabled;
+	bool bridged;
 	atomic_t num_disabled;
 	atomic_t num_want_all_unsnoopables;
 	atomic_t num_want_all_ipv4;
-- 
1.7.10.4

[B.A.T.M.A.N.] [PATCHv7 3/3] batman-adv: Add debugfs table for mcast flags

[Linus Lüssing]

This patch adds a debugfs table with originators and their according
multicast flags to help users figure out why multicast optimizations
might be enabled or disabled for them.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
 debugfs.c   |   21 +++++++++++++
 multicast.c |   99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 multicast.h |    2 ++
 3 files changed, 122 insertions(+)

diff --git a/debugfs.c b/debugfs.c
index a12e25e..cd7c282 100644
--- a/debugfs.c
+++ b/debugfs.c
@@ -30,6 +30,7 @@
 #include "bridge_loop_avoidance.h"
 #include "distributed-arp-table.h"
 #include "network-coding.h"
+#include "multicast.h"
 
 static struct dentry *batadv_debugfs;
 
@@ -332,6 +333,20 @@ static int batadv_nc_nodes_open(struct inode *inode, struct file *file)
 }
 #endif
 
+#ifdef CONFIG_BATMAN_ADV_MCAST
+/**
+ * batadv_mcast_flags_open - prepare file handler for reads from mcast_flags
+ * @inode: inode which was opened
+ * @file: file handle to be initialized
+ */
+static int batadv_mcast_flags_open(struct inode *inode, struct file *file)
+{
+	struct net_device *net_dev = (struct net_device *)inode->i_private;
+
+	return single_open(file, batadv_mcast_flags_seq_print_text, net_dev);
+}
+#endif
+
 #define BATADV_DEBUGINFO(_name, _mode, _open)		\
 struct batadv_debuginfo batadv_debuginfo_##_name = {	\
 	.attr = { .name = __stringify(_name),		\
@@ -372,6 +387,9 @@ static BATADV_DEBUGINFO(transtable_local, S_IRUGO,
 #ifdef CONFIG_BATMAN_ADV_NC
 static BATADV_DEBUGINFO(nc_nodes, S_IRUGO, batadv_nc_nodes_open);
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST
+static BATADV_DEBUGINFO(mcast_flags, S_IRUGO, batadv_mcast_flags_open);
+#endif
 
 static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
 	&batadv_debuginfo_originators,
@@ -388,6 +406,9 @@ static struct batadv_debuginfo *batadv_mesh_debuginfos[] = {
 #ifdef CONFIG_BATMAN_ADV_NC
 	&batadv_debuginfo_nc_nodes,
 #endif
+#ifdef CONFIG_BATMAN_ADV_MCAST
+	&batadv_debuginfo_mcast_flags,
+#endif
 	NULL,
 };
 
diff --git a/multicast.c b/multicast.c
index 915582d..621f86d 100644
--- a/multicast.c
+++ b/multicast.c
@@ -981,6 +981,105 @@ void batadv_mcast_init(struct batadv_priv *bat_priv)
 }
 
 /**
+ * batadv_mcast_flags_print_header - print own mcast flags to debugfs table
+ * @bat_priv: the bat priv with all the soft interface information
+ * @seq: debugfs table seq_file struct
+ *
+ * Prints our own multicast flags including a more specific reason why
+ * they are set, that is prints the bridge and querier state too, to
+ * the debugfs table specified via @seq.
+ */
+static void batadv_mcast_flags_print_header(struct batadv_priv *bat_priv,
+					    struct seq_file *seq)
+{
+	uint8_t flags = bat_priv->mcast.flags;
+	char querier4, querier6, shadowing4, shadowing6;
+	bool bridged = bat_priv->mcast.bridged;
+
+	if (bridged) {
+		querier4 = bat_priv->mcast.querier_ipv4.exists ? '+' : '-';
+		querier6 = bat_priv->mcast.querier_ipv6.exists ? '+' : '-';
+		shadowing4 = bat_priv->mcast.querier_ipv4.shadowing ? '+' : '-';
+		shadowing6 = bat_priv->mcast.querier_ipv6.shadowing ? '+' : '-';
+	} else {
+		querier4 = '?';
+		querier6 = '?';
+		shadowing4 = '?';
+		shadowing6 = '?';
+	}
+
+	seq_printf(seq, "Multicast flags (own flags: [%c%c%c])\n",
+		   flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES ? 'U' : '.',
+		   flags & BATADV_MCAST_WANT_ALL_IPV4 ? '4' : '.',
+		   flags & BATADV_MCAST_WANT_ALL_IPV6 ? '6' : '.');
+	seq_printf(seq, "* Bridged [U]\t\t\t\t%c\n", bridged ? '+' : '-');
+	seq_printf(seq, "* No IGMP/MLD Querier [4/6]:\t\t%c/%c\n",
+		   querier4, querier6);
+	seq_printf(seq, "* Shadowing IGMP/MLD Querier [4/6]:\t%c/%c\n",
+		   shadowing4, shadowing6);
+	seq_puts(seq, "-------------------------------------------\n");
+	seq_printf(seq, "       %-10s %s\n", "Originator", "Flags");
+}
+
+/**
+ * batadv_mcast_flags_seq_print_text - print the mcast flags of other nodes
+ * @seq: seq file to print on
+ * @offset: not used
+ *
+ * This prints a table of (primary) originators and their according
+ * multicast flags, including (in the header) our own.
+ */
+int batadv_mcast_flags_seq_print_text(struct seq_file *seq, void *offset)
+{
+	struct net_device *net_dev = (struct net_device *)seq->private;
+	struct batadv_priv *bat_priv = netdev_priv(net_dev);
+	struct batadv_hard_iface *primary_if;
+	struct batadv_hashtable *hash = bat_priv->orig_hash;
+	struct batadv_orig_node *orig_node;
+	struct hlist_head *head;
+	uint8_t flags;
+	uint32_t i;
+
+	primary_if = batadv_seq_print_text_primary_if_get(seq);
+	if (!primary_if)
+		return 0;
+
+	batadv_mcast_flags_print_header(bat_priv, seq);
+
+	for (i = 0; i < hash->size; i++) {
+		head = &hash->table[i];
+
+		rcu_read_lock();
+		hlist_for_each_entry_rcu(orig_node, head, hash_entry) {
+			if (!(orig_node->capa_initialized &
+			      BATADV_ORIG_CAPA_HAS_MCAST))
+				continue;
+
+			flags = orig_node->mcast_flags;
+
+			if (!(orig_node->capabilities &
+			      BATADV_ORIG_CAPA_HAS_MCAST)) {
+				seq_printf(seq, "%pM -\n", orig_node->orig);
+				continue;
+			}
+
+			seq_printf(seq, "%pM [%c%c%c]\n", orig_node->orig,
+				   (flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES ?
+				    'U' : '.'),
+				   (flags & BATADV_MCAST_WANT_ALL_IPV4 ?
+				    '4' : '.'),
+				   (flags & BATADV_MCAST_WANT_ALL_IPV6 ?
+				    '6' : '.'));
+		}
+		rcu_read_unlock();
+	}
+
+	batadv_hardif_free_ref(primary_if);
+
+	return 0;
+}
+
+/**
  * batadv_mcast_free - free the multicast optimizations structures
  * @bat_priv: the bat priv with all the soft interface information
  */
diff --git a/multicast.h b/multicast.h
index 73b5d45..5344160 100644
--- a/multicast.h
+++ b/multicast.h
@@ -42,6 +42,8 @@ batadv_mcast_forw_mode(struct batadv_priv *bat_priv, struct sk_buff *skb,
 
 void batadv_mcast_init(struct batadv_priv *bat_priv);
 
+int batadv_mcast_flags_seq_print_text(struct seq_file *seq, void *offset);
+
 void batadv_mcast_free(struct batadv_priv *bat_priv);
 
 void batadv_mcast_purge_orig(struct batadv_orig_node *orig_node);
-- 
1.7.10.4

Re: [B.A.T.M.A.N.] [PATCHv7 0/3] Multicast optimizations for bridges

[Simon Wunderlich]

On Friday 08 August 2014 04:46:26 Linus Lüssing wrote:
> This patchset enables the usage of the batman-adv multicast optimizations
> for scenarios involving bridges on top of e.g. bat0, too.
> 
> Along come two more patches adding according debugging facilities
> to make it possible for the user to check why the multicast
> optimizations might not work ideally to give hints about
> what they might change about their topology.
> 
> Cheers, Linus

As discussed in private, here are some things which I've noticed during my 
tests which should get fixed:

 * With batctl mf, in the own flag section, it reports "no querier present +" 
when there is actually a querier present, and "no querier present -" if there 
is no querier -> reversed logic?
 * As a beautification suggestion, you could use the flag names (U/4/6) instead 
of "+" and "." instead of "-" in the batctl mf output to make the connection 
to the reported flags more clear
 * I didn't get any log output (from batctl log) when a querier was shadowed, 
even if batctl mf was showing that correctly. All what was reported was 
IGMP/MLD querier appearing or disappearing. We've discussed that this might be 
due to some delay in the bridge code to report that ...

In general, the tests went fine, if you can resolve these quirks then we can 
add my Reviewed/Tested by, I guess. :)

Thanks!
    Simon