[B.A.T.M.A.N.] [PATCHv2 net-next 4/4] bridge: memorize and export selected IGMP/MLD querier port

Linus Lüssing
2014-05-25T05:03:25Z

Adding bridge support to the batman-adv multicast optimization requires
batman-adv knowing about the existence of bridged-in IGMP/MLD queriers
to be able to reliably serve any multicast listener behind this same
bridge.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
---
include/linux/if_bridge.h | 1 +
net/bridge/br_multicast.c | 72 +++++++++++++++++++++++++++++++++++++++++----
net/bridge/br_private.h | 1 +
3 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 44d6eb0..fd22789 100644
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -38,5 +38,6 @@ typedef int br_should_route_hook_t(struct sk_buff *skb);
extern br_should_route_hook_t __rcu *br_should_route_hook;
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);

#endif
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 807e535..3c9b405 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1081,6 +1081,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br,
#endif

static bool br_ip4_multicast_select_querier(struct net_bridge *br,
+ struct net_bridge_port *port,
__be32 saddr)
{
if (!timer_pending(&br->ip4_own_query.timer) &&
@@ -1098,11 +1099,15 @@ static bool br_ip4_multicast_select_querier(struct net_bridge *br,
update:
br->ip4_querier.addr.u.ip4 = saddr;

+ /* update protected by general multicast_lock by caller */
+ rcu_assign_pointer(br->ip4_querier.port, port);
+
return true;
}

#if IS_ENABLED(CONFIG_IPV6)
static bool br_ip6_multicast_select_querier(struct net_bridge *br,
+ struct net_bridge_port *port,
struct in6_addr *saddr)
{
if (!timer_pending(&br->ip6_own_query.timer) &&
@@ -1117,19 +1122,23 @@ static bool br_ip6_multicast_select_querier(struct net_bridge *br,
update:
br->ip6_querier.addr.u.ip6 = *saddr;

+ /* update protected by general multicast_lock by caller */
+ rcu_assign_pointer(br->ip6_querier.port, port);
+
return true;
}
#endif

static bool br_multicast_select_querier(struct net_bridge *br,
+ struct net_bridge_port *port,
struct br_ip *saddr)
{
switch (saddr->proto) {
case htons(ETH_P_IP):
- return br_ip4_multicast_select_querier(br, saddr->u.ip4);
+ return br_ip4_multicast_select_querier(br, port, saddr->u.ip4);
#if IS_ENABLED(CONFIG_IPV6)
case htons(ETH_P_IPV6):
- return br_ip6_multicast_select_querier(br, &saddr->u.ip6);
+ return br_ip6_multicast_select_querier(br, port, &saddr->u.ip6);
#endif
}

@@ -1201,7 +1210,7 @@ static void br_multicast_query_received(struct net_bridge *br,
struct br_ip *saddr,
unsigned long max_delay)
{
- if (!br_multicast_select_querier(br, saddr))
+ if (!br_multicast_select_querier(br, port, saddr))
return;

br_multicast_update_query_timer(br, query, max_delay);
@@ -1804,12 +1813,14 @@ int br_multicast_rcv(struct net_bridge *br, struct net_bridge_port *port,
}

static void br_multicast_query_expired(struct net_bridge *br,
- struct bridge_mcast_own_query *query)
+ struct bridge_mcast_own_query *query,
+ struct bridge_mcast_querier *querier)
{
spin_lock(&br->multicast_lock);
if (query->startup_sent < br->multicast_startup_query_count)
query->startup_sent++;

+ rcu_assign_pointer(querier, NULL);
br_multicast_send_query(br, NULL, query);
spin_unlock(&br->multicast_lock);
}
@@ -1818,7 +1829,7 @@ static void br_ip4_multicast_query_expired(unsigned long data)
{
struct net_bridge *br = (void *)data;

- br_multicast_query_expired(br, &br->ip4_own_query);
+ br_multicast_query_expired(br, &br->ip4_own_query, &br->ip4_querier);
}

#if IS_ENABLED(CONFIG_IPV6)
@@ -1826,7 +1837,7 @@ static void br_ip6_multicast_query_expired(unsigned long data)
{
struct net_bridge *br = (void *)data;

- br_multicast_query_expired(br, &br->ip6_own_query);
+ br_multicast_query_expired(br, &br->ip6_own_query, &br->ip6_querier);
}
#endif

@@ -1849,8 +1860,10 @@ void br_multicast_init(struct net_bridge *br)
br->multicast_membership_interval = 260 * HZ;

br->ip4_other_query.delay_time = 0;
+ br->ip4_querier.port = NULL;
#if IS_ENABLED(CONFIG_IPV6)
br->ip6_other_query.delay_time = 0;
+ br->ip6_querier.port = NULL;
#endif

spin_lock_init(&br->multicast_lock);
@@ -2199,3 +2212,50 @@ unlock:
return count;
}
EXPORT_SYMBOL(br_multicast_list_adjacent);
+
+/**
+ * br_multicast_has_querier_adjacent - Checks for a querier behind a bridge port
+ * @dev: The bridge port adjacent to which to check for a querier
+ * @proto: The protocol family to check for: IGMP -> ETH_P_IP, MLD -> ETH_P_IPV6
+ *
+ * Checks whether the given interface has a bridge on top and if so returns
+ * true if a selected querier is behind one of the other ports of this
+ * bridge. Otherwise returns false.
+ */
+bool br_multicast_has_querier_adjacent(struct net_device *dev, int proto)
+{
+ struct net_bridge *br;
+ struct net_bridge_port *port;
+ bool ret = false;
+
+ rcu_read_lock();
+ if (!br_port_exists(dev))
+ goto unlock;
+
+ port = br_port_get_rcu(dev);
+ if (!port || !port->br)
+ goto unlock;
+
+ br = port->br;
+
+ switch (proto) {
+ case ETH_P_IP:
+ if (!timer_pending(&br->ip4_other_query.timer) ||
+ rcu_dereference(br->ip4_querier.port) == port)
+ goto unlock;
+ break;
+ case ETH_P_IPV6:
+ if (!timer_pending(&br->ip6_other_query.timer) ||
+ rcu_dereference(br->ip6_querier.port) == port)
+ goto unlock;
+ break;
+ default:
+ goto unlock;
+ }
+
+ ret = true;
+unlock:
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL(br_multicast_has_querier_adjacent);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index cb704a6..625d1bf 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -70,6 +70,7 @@ struct bridge_mcast_other_query {
/* selected querier */
struct bridge_mcast_querier {
struct br_ip addr;
+ struct net_bridge_port __rcu *port;
};
#endif

--
1.7.10.4