[B.A.T.M.A.N.] [PATCHv12 3/4] batman-adv: Adding logging of mcast flag changes

Linus Lüssing
2016-03-16T04:06:44Z

With this patch changes relevant to a node's own multicast flags are
printed to the 'mcast' log level.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
net/batman-adv/main.h | 4 +-
net/batman-adv/multicast.c | 164 +++++++++++++++++++++++++++++++++++----
net/batman-adv/soft-interface.c | 4 +
net/batman-adv/types.h | 15 ++++
4 files changed, 170 insertions(+), 17 deletions(-)

diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index e602408..c1c6a32 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -227,6 +227,7 @@ __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 {
@@ -236,7 +237,8 @@ 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/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 34abe39..41ba2e8 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -367,6 +367,122 @@ batadv_mcast_handler_unregister(struct batadv_priv *bat_priv, u8 version)
}

/**
+ * 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_info(bat_priv->soft_iface, "%s Querier appeared\n",
+ str_proto);
+ else if (old_state->exists && !new_state->exists)
+ batadv_info(bat_priv->soft_iface,
+ "%s Querier disappeared - multicast optimizations disabled\n",
+ str_proto);
+ else if (!bat_priv->mcast.bridged && !new_state->exists)
+ batadv_info(bat_priv->soft_iface,
+ "No %s Querier present - multicast optimizations disabled\n",
+ str_proto);
+
+ if (new_state->exists) {
+ if ((!old_state->shadowing && new_state->shadowing) ||
+ (!old_state->exists && 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, u8 flags)
+{
+ u8 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
*
@@ -379,29 +495,28 @@ batadv_mcast_handler_unregister(struct batadv_priv *bat_priv, u8 version)
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)) {
- if (bat_priv->mcast.bridged || !bat_priv->mcast.enabled) {
- batadv_mcast_handler_register(bat_priv, 1);
- bat_priv->mcast.bridged = false;
- }
-
+ bridged = batadv_mcast_has_bridge(bat_priv);
+ if (!bridged)
goto update;
- }
-
- if (bat_priv->mcast.enabled && !bat_priv->mcast.bridged)
- batadv_mcast_handler_unregister(bat_priv, 1);
-
- bat_priv->mcast.bridged = true;

#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
@@ -413,17 +528,34 @@ 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.exists = querier4.exists;
+ bat_priv->mcast.querier_ipv4.shadowing = querier4.shadowing;
+
+ bat_priv->mcast.querier_ipv6.exists = querier6.exists;
+ bat_priv->mcast.querier_ipv6.shadowing = querier6.shadowing;
+
+ if (bridged) {
+ if (!bat_priv->mcast.enabled || !bat_priv->mcast.bridged)
+ batadv_mcast_handler_register(bat_priv, 1);
+ } else {
+ if (bat_priv->mcast.bridged)
+ batadv_mcast_handler_unregister(bat_priv, 1);
+ }
+
+ bat_priv->mcast.bridged = bridged;
+
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));
batadv_tvlv_container_register(bat_priv, BATADV_TVLV_MCAST, 2,
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 7679f3a..2d0cd6f 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -791,6 +791,10 @@ 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;
atomic_set(&bat_priv->multicast_mode, 1);
atomic_set(&bat_priv->mcast.num_disabled, 0);
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index f793c57..330e9de 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -743,12 +743,25 @@ 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
+ * @querier_ipv6: the current state of an MLD querier in the mesh
* @flags: the flags we have last sent in our mcast tvlv
* @enabled: whether the multicast tvlv is currently enabled
* @bridged: whether the soft interface has a bridge on top
@@ -764,6 +777,8 @@ 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;
u8 flags;
bool enabled;
bool bridged;
--
1.7.10.4