thr3ads.net - Linux Ethernet Bridging - [Bridge] [PATCH net-next 2/6] net: bridge: mcast: make sure querier port/address updates are consistent [Aug 2021]

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Nikolay Aleksandrov

2021-Aug-13 14:59 UTC

[Bridge] [PATCH net-next 0/6] net: bridge: mcast: dump querier state

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Hi,
This set adds the ability to dump the current multicast querier state.
This is extremely useful when debugging multicast issues, we've had
many cases of unexpected queriers causing strange behaviour and mcast
test failures. The first patch changes the querier struct to record
a port device's ifindex instead of a pointer to the port itself so we
can later retrieve it, I chose this way because it's much simpler
and doesn't require us to do querier port ref counting, it is best
effort anyway. Then patch 02 makes the querier address/port updates
consistent via a combination of multicast_lock and seqcount, so readers
can only use seqcount to get a consistent snapshot of address and port.
Patch 03 is a minor cleanup in preparation for the dump support, it
consolidates IPv4 and IPv6 querier selection paths as they share most of
the logic (except address comparisons of course). Finally the last three
patches add the new querier state dumping support, for the bridge's
global multicast context we embed the BRIDGE_QUERIER_xxx attributes
into IFLA_BR_MCAST_QUERIER_STATE and for the per-vlan global mcast
contexts we embed them into BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE.

The structure is:
  [IFLA_BR_MCAST_QUERIER_STATE / BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE]
  `[BRIDGE_QUERIER_IP_ADDRESS] - ip address of the querier
  `[BRIDGE_QUERIER_IP_PORT]    - bridge port ifindex where the querier was
                                 seen (set only if external querier)
  `[BRIDGE_QUERIER_IP_OTHER_TIMER]   -  other querier timeout
  `[BRIDGE_QUERIER_IPV6_ADDRESS] - ip address of the querier
  `[BRIDGE_QUERIER_IPV6_PORT]    - bridge port ifindex where the querier
                                   was seen (set only if external querier)
  `[BRIDGE_QUERIER_IPV6_OTHER_TIMER]   -  other querier timeout

Later we can also add IGMP version of seen queriers and last seen values
from the queries.

Thanks,
 Nik

Nikolay Aleksandrov (6):
  net: bridge: mcast: record querier port device ifindex instead of
    pointer
  net: bridge: mcast: make sure querier port/address updates are
    consistent
  net: bridge: mcast: consolidate querier selection for ipv4 and ipv6
  net: bridge: mcast: dump ipv4 querier state
  net: bridge: mcast: dump ipv6 querier state
  net: bridge: vlan: dump mcast ctx querier state

 include/uapi/linux/if_bridge.h |  14 +++
 include/uapi/linux/if_link.h   |   1 +
 net/bridge/br_multicast.c      | 211 ++++++++++++++++++++++++++-------
 net/bridge/br_netlink.c        |   5 +-
 net/bridge/br_private.h        |   7 +-
 net/bridge/br_vlan_options.c   |   5 +-
 6 files changed, 199 insertions(+), 44 deletions(-)

-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 14:59 UTC

head link

[Bridge] [PATCH net-next 1/6] net: bridge: mcast: record querier port device ifindex instead of pointer

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Currently when a querier port is detected its net_bridge_port pointer is
recorded, but it's used only for comparisons so it's fine to have stale
pointer, in order to dereference and use the port pointer a proper
accounting of its usage must be implemented adding unnecessary
complexity. To solve the problem we can just store the netdevice ifindex
instead of the port pointer and retrieve the bridge port. It is a best
effort and the device needs to be validated that is still part of that
bridge before use, but that is small price to pay for avoiding querier
reference counting for each port/vlan.

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 net/bridge/br_multicast.c | 19 ++++++++++++-------
 net/bridge/br_private.h   |  2 +-
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index df6bf6a237aa..853b947edf87 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2850,7 +2850,8 @@ static bool br_ip4_multicast_select_querier(struct
net_bridge_mcast *brmctx,
 	brmctx->ip4_querier.addr.src.ip4 = saddr;
 
 	/* update protected by general multicast_lock by caller */
-	rcu_assign_pointer(brmctx->ip4_querier.port, port);
+	if (port)
+		brmctx->ip4_querier.port_ifidx = port->dev->ifindex;
 
 	return true;
 }
@@ -2875,7 +2876,8 @@ static bool br_ip6_multicast_select_querier(struct
net_bridge_mcast *brmctx,
 	brmctx->ip6_querier.addr.src.ip6 = *saddr;
 
 	/* update protected by general multicast_lock by caller */
-	rcu_assign_pointer(brmctx->ip6_querier.port, port);
+	if (port)
+		brmctx->ip6_querier.port_ifidx = port->dev->ifindex;
 
 	return true;
 }
@@ -3675,7 +3677,7 @@ static void br_multicast_query_expired(struct
net_bridge_mcast *brmctx,
 	if (query->startup_sent < brmctx->multicast_startup_query_count)
 		query->startup_sent++;
 
-	RCU_INIT_POINTER(querier->port, NULL);
+	querier->port_ifidx = 0;
 	br_multicast_send_query(brmctx, NULL, query);
 out:
 	spin_unlock(&brmctx->br->multicast_lock);
@@ -3732,12 +3734,12 @@ void br_multicast_ctx_init(struct net_bridge *br,
 	brmctx->multicast_membership_interval = 260 * HZ;
 
 	brmctx->ip4_other_query.delay_time = 0;
-	brmctx->ip4_querier.port = NULL;
+	brmctx->ip4_querier.port_ifidx = 0;
 	brmctx->multicast_igmp_version = 2;
 #if IS_ENABLED(CONFIG_IPV6)
 	brmctx->multicast_mld_version = 1;
 	brmctx->ip6_other_query.delay_time = 0;
-	brmctx->ip6_querier.port = NULL;
+	brmctx->ip6_querier.port_ifidx = 0;
 #endif
 
 	timer_setup(&brmctx->ip4_mc_router_timer,
@@ -4479,6 +4481,7 @@ bool br_multicast_has_querier_adjacent(struct net_device
*dev, int proto)
 	struct net_bridge *br;
 	struct net_bridge_port *port;
 	bool ret = false;
+	int port_ifidx;
 
 	rcu_read_lock();
 	if (!netif_is_bridge_port(dev))
@@ -4493,14 +4496,16 @@ bool br_multicast_has_querier_adjacent(struct net_device
*dev, int proto)
 
 	switch (proto) {
 	case ETH_P_IP:
+		port_ifidx = brmctx->ip4_querier.port_ifidx;
 		if (!timer_pending(&brmctx->ip4_other_query.timer) ||
-		    rcu_dereference(brmctx->ip4_querier.port) == port)
+		    port_ifidx == port->dev->ifindex)
 			goto unlock;
 		break;
 #if IS_ENABLED(CONFIG_IPV6)
 	case ETH_P_IPV6:
+		port_ifidx = brmctx->ip6_querier.port_ifidx;
 		if (!timer_pending(&brmctx->ip6_other_query.timer) ||
-		    rcu_dereference(brmctx->ip6_querier.port) == port)
+		    port_ifidx == port->dev->ifindex)
 			goto unlock;
 		break;
 #endif
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 32c218aa3f36..b92fab5ae0fb 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -81,7 +81,7 @@ struct bridge_mcast_other_query {
 /* selected querier */
 struct bridge_mcast_querier {
 	struct br_ip addr;
-	struct net_bridge_port __rcu	*port;
+	int port_ifidx;
 };
 
 /* IGMP/MLD statistics */
-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 14:59 UTC

head link

[Bridge] [PATCH net-next 2/6] net: bridge: mcast: make sure querier port/address updates are consistent

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Use a sequence counter to make sure port/address updates can be read
consistently without requiring the bridge multicast_lock. We need to
zero out the port and address when the other querier has expired and
we're about to select ourselves as querier. br_multicast_read_querier
will be used later when dumping querier state. Updates are done only
with the multicast spinlock and softirqs disabled, while reads are done
from process context and from softirqs (due to notifications).

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 net/bridge/br_multicast.c | 74 ++++++++++++++++++++++++++++-----------
 net/bridge/br_private.h   |  1 +
 2 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 853b947edf87..701cf46b89de 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1659,11 +1659,38 @@ static void __br_multicast_send_query(struct
net_bridge_mcast *brmctx,
 	}
 }
 
+static void br_multicast_read_querier(const struct bridge_mcast_querier
*querier,
+				      struct bridge_mcast_querier *dest)
+{
+	unsigned int seq;
+
+	memset(dest, 0, sizeof(*dest));
+	do {
+		seq = read_seqcount_begin(&querier->seq);
+		dest->port_ifidx = querier->port_ifidx;
+		memcpy(&dest->addr, &querier->addr, sizeof(struct br_ip));
+	} while (read_seqcount_retry(&querier->seq, seq));
+}
+
+static void br_multicast_update_querier(struct net_bridge_mcast *brmctx,
+					struct bridge_mcast_querier *querier,
+					int ifindex,
+					struct br_ip *saddr)
+{
+	lockdep_assert_held_once(&brmctx->br->multicast_lock);
+
+	write_seqcount_begin(&querier->seq);
+	querier->port_ifidx = ifindex;
+	memcpy(&querier->addr, saddr, sizeof(*saddr));
+	write_seqcount_end(&querier->seq);
+}
+
 static void br_multicast_send_query(struct net_bridge_mcast *brmctx,
 				    struct net_bridge_mcast_port *pmctx,
 				    struct bridge_mcast_own_query *own_query)
 {
 	struct bridge_mcast_other_query *other_query = NULL;
+	struct bridge_mcast_querier *querier;
 	struct br_ip br_group;
 	unsigned long time;
 
@@ -1676,10 +1703,12 @@ static void br_multicast_send_query(struct
net_bridge_mcast *brmctx,
 
 	if (pmctx ? (own_query == &pmctx->ip4_own_query) :
 		    (own_query == &brmctx->ip4_own_query)) {
+		querier = &brmctx->ip4_querier;
 		other_query = &brmctx->ip4_other_query;
 		br_group.proto = htons(ETH_P_IP);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
+		querier = &brmctx->ip6_querier;
 		other_query = &brmctx->ip6_other_query;
 		br_group.proto = htons(ETH_P_IPV6);
 #endif
@@ -1688,6 +1717,13 @@ static void br_multicast_send_query(struct
net_bridge_mcast *brmctx,
 	if (!other_query || timer_pending(&other_query->timer))
 		return;
 
+	/* we're about to select ourselves as querier */
+	if (!pmctx && querier->port_ifidx) {
+		struct br_ip zeroip = {};
+
+		br_multicast_update_querier(brmctx, querier, 0, &zeroip);
+	}
+
 	__br_multicast_send_query(brmctx, pmctx, NULL, NULL, &br_group, false,
 				  0, NULL);
 
@@ -2830,9 +2866,9 @@ static int br_ip6_multicast_mld2_report(struct
net_bridge_mcast *brmctx,
 
 static bool br_ip4_multicast_select_querier(struct net_bridge_mcast *brmctx,
 					    struct net_bridge_mcast_port *pmctx,
-					    __be32 saddr)
+					    struct br_ip *saddr)
 {
-	struct net_bridge_port *port = pmctx ? pmctx->port : NULL;
+	int port_ifidx = pmctx ? pmctx->port->dev->ifindex : 0;
 
 	if (!timer_pending(&brmctx->ip4_own_query.timer) &&
 	    !timer_pending(&brmctx->ip4_other_query.timer))
@@ -2841,17 +2877,14 @@ static bool br_ip4_multicast_select_querier(struct
net_bridge_mcast *brmctx,
 	if (!brmctx->ip4_querier.addr.src.ip4)
 		goto update;
 
-	if (ntohl(saddr) <= ntohl(brmctx->ip4_querier.addr.src.ip4))
+	if (ntohl(saddr->src.ip4) <= ntohl(brmctx->ip4_querier.addr.src.ip4))
 		goto update;
 
 	return false;
 
 update:
-	brmctx->ip4_querier.addr.src.ip4 = saddr;
-
-	/* update protected by general multicast_lock by caller */
-	if (port)
-		brmctx->ip4_querier.port_ifidx = port->dev->ifindex;
+	br_multicast_update_querier(brmctx, &brmctx->ip4_querier, port_ifidx,
+				    saddr);
 
 	return true;
 }
@@ -2859,25 +2892,23 @@ static bool br_ip4_multicast_select_querier(struct
net_bridge_mcast *brmctx,
 #if IS_ENABLED(CONFIG_IPV6)
 static bool br_ip6_multicast_select_querier(struct net_bridge_mcast *brmctx,
 					    struct net_bridge_mcast_port *pmctx,
-					    struct in6_addr *saddr)
+					    struct br_ip *saddr)
 {
-	struct net_bridge_port *port = pmctx ? pmctx->port : NULL;
+	int port_ifidx = pmctx ? pmctx->port->dev->ifindex : 0;
 
 	if (!timer_pending(&brmctx->ip6_own_query.timer) &&
 	    !timer_pending(&brmctx->ip6_other_query.timer))
 		goto update;
 
-	if (ipv6_addr_cmp(saddr, &brmctx->ip6_querier.addr.src.ip6) <= 0)
+	if (ipv6_addr_cmp(&saddr->src.ip6,
+			  &brmctx->ip6_querier.addr.src.ip6) <= 0)
 		goto update;
 
 	return false;
 
 update:
-	brmctx->ip6_querier.addr.src.ip6 = *saddr;
-
-	/* update protected by general multicast_lock by caller */
-	if (port)
-		brmctx->ip6_querier.port_ifidx = port->dev->ifindex;
+	br_multicast_update_querier(brmctx, &brmctx->ip6_querier, port_ifidx,
+				    saddr);
 
 	return true;
 }
@@ -3084,7 +3115,7 @@ br_ip4_multicast_query_received(struct net_bridge_mcast
*brmctx,
 				struct br_ip *saddr,
 				unsigned long max_delay)
 {
-	if (!br_ip4_multicast_select_querier(brmctx, pmctx, saddr->src.ip4))
+	if (!br_ip4_multicast_select_querier(brmctx, pmctx, saddr))
 		return;
 
 	br_multicast_update_query_timer(brmctx, query, max_delay);
@@ -3099,7 +3130,7 @@ br_ip6_multicast_query_received(struct net_bridge_mcast
*brmctx,
 				struct br_ip *saddr,
 				unsigned long max_delay)
 {
-	if (!br_ip6_multicast_select_querier(brmctx, pmctx, &saddr->src.ip6))
+	if (!br_ip6_multicast_select_querier(brmctx, pmctx, saddr))
 		return;
 
 	br_multicast_update_query_timer(brmctx, query, max_delay);
@@ -3119,7 +3150,7 @@ static void br_ip4_multicast_query(struct net_bridge_mcast
*brmctx,
 	struct igmpv3_query *ih3;
 	struct net_bridge_port_group *p;
 	struct net_bridge_port_group __rcu **pp;
-	struct br_ip saddr;
+	struct br_ip saddr = {};
 	unsigned long max_delay;
 	unsigned long now = jiffies;
 	__be32 group;
@@ -3199,7 +3230,7 @@ static int br_ip6_multicast_query(struct net_bridge_mcast
*brmctx,
 	struct mld2_query *mld2q;
 	struct net_bridge_port_group *p;
 	struct net_bridge_port_group __rcu **pp;
-	struct br_ip saddr;
+	struct br_ip saddr = {};
 	unsigned long max_delay;
 	unsigned long now = jiffies;
 	unsigned int offset = skb_transport_offset(skb);
@@ -3677,7 +3708,6 @@ static void br_multicast_query_expired(struct
net_bridge_mcast *brmctx,
 	if (query->startup_sent < brmctx->multicast_startup_query_count)
 		query->startup_sent++;
 
-	querier->port_ifidx = 0;
 	br_multicast_send_query(brmctx, NULL, query);
 out:
 	spin_unlock(&brmctx->br->multicast_lock);
@@ -3735,11 +3765,13 @@ void br_multicast_ctx_init(struct net_bridge *br,
 
 	brmctx->ip4_other_query.delay_time = 0;
 	brmctx->ip4_querier.port_ifidx = 0;
+	seqcount_init(&brmctx->ip4_querier.seq);
 	brmctx->multicast_igmp_version = 2;
 #if IS_ENABLED(CONFIG_IPV6)
 	brmctx->multicast_mld_version = 1;
 	brmctx->ip6_other_query.delay_time = 0;
 	brmctx->ip6_querier.port_ifidx = 0;
+	seqcount_init(&brmctx->ip6_querier.seq);
 #endif
 
 	timer_setup(&brmctx->ip4_mc_router_timer,
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index b92fab5ae0fb..6ca9519f18a3 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -82,6 +82,7 @@ struct bridge_mcast_other_query {
 struct bridge_mcast_querier {
 	struct br_ip addr;
 	int port_ifidx;
+	seqcount_t seq;
 };
 
 /* IGMP/MLD statistics */
-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 14:59 UTC

head link

[Bridge] [PATCH net-next 3/6] net: bridge: mcast: consolidate querier selection for ipv4 and ipv6

From: Nikolay Aleksandrov <nikolay at nvidia.com>

We can consolidate both functions as they share almost the same logic.
This is easier to maintain and we have a single querier update function.

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 net/bridge/br_multicast.c | 67 +++++++++++++++++----------------------
 1 file changed, 29 insertions(+), 38 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 701cf46b89de..3705b7ace62d 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2864,55 +2864,46 @@ static int br_ip6_multicast_mld2_report(struct
net_bridge_mcast *brmctx,
 }
 #endif
 
-static bool br_ip4_multicast_select_querier(struct net_bridge_mcast *brmctx,
-					    struct net_bridge_mcast_port *pmctx,
-					    struct br_ip *saddr)
+static bool br_multicast_select_querier(struct net_bridge_mcast *brmctx,
+					struct net_bridge_mcast_port *pmctx,
+					struct br_ip *saddr)
 {
 	int port_ifidx = pmctx ? pmctx->port->dev->ifindex : 0;
+	struct timer_list *own_timer, *other_timer;
+	struct bridge_mcast_querier *querier;
 
-	if (!timer_pending(&brmctx->ip4_own_query.timer) &&
-	    !timer_pending(&brmctx->ip4_other_query.timer))
-		goto update;
-
-	if (!brmctx->ip4_querier.addr.src.ip4)
-		goto update;
-
-	if (ntohl(saddr->src.ip4) <= ntohl(brmctx->ip4_querier.addr.src.ip4))
-		goto update;
-
-	return false;
-
-update:
-	br_multicast_update_querier(brmctx, &brmctx->ip4_querier, port_ifidx,
-				    saddr);
-
-	return true;
-}
-
+	switch (saddr->proto) {
+	case htons(ETH_P_IP):
+		querier = &brmctx->ip4_querier;
+		own_timer = &brmctx->ip4_own_query.timer;
+		other_timer = &brmctx->ip4_other_query.timer;
+		if (!querier->addr.src.ip4 ||
+		    ntohl(saddr->src.ip4) <= ntohl(querier->addr.src.ip4))
+			goto update;
+		break;
 #if IS_ENABLED(CONFIG_IPV6)
-static bool br_ip6_multicast_select_querier(struct net_bridge_mcast *brmctx,
-					    struct net_bridge_mcast_port *pmctx,
-					    struct br_ip *saddr)
-{
-	int port_ifidx = pmctx ? pmctx->port->dev->ifindex : 0;
-
-	if (!timer_pending(&brmctx->ip6_own_query.timer) &&
-	    !timer_pending(&brmctx->ip6_other_query.timer))
-		goto update;
+	case htons(ETH_P_IPV6):
+		querier = &brmctx->ip6_querier;
+		own_timer = &brmctx->ip6_own_query.timer;
+		other_timer = &brmctx->ip6_other_query.timer;
+		if (ipv6_addr_cmp(&saddr->src.ip6, &querier->addr.src.ip6)
<= 0)
+			goto update;
+		break;
+#endif
+	default:
+		return false;
+	}
 
-	if (ipv6_addr_cmp(&saddr->src.ip6,
-			  &brmctx->ip6_querier.addr.src.ip6) <= 0)
+	if (!timer_pending(own_timer) && !timer_pending(other_timer))
 		goto update;
 
 	return false;
 
 update:
-	br_multicast_update_querier(brmctx, &brmctx->ip6_querier, port_ifidx,
-				    saddr);
+	br_multicast_update_querier(brmctx, querier, port_ifidx, saddr);
 
 	return true;
 }
-#endif
 
 static void
 br_multicast_update_query_timer(struct net_bridge_mcast *brmctx,
@@ -3115,7 +3106,7 @@ br_ip4_multicast_query_received(struct net_bridge_mcast
*brmctx,
 				struct br_ip *saddr,
 				unsigned long max_delay)
 {
-	if (!br_ip4_multicast_select_querier(brmctx, pmctx, saddr))
+	if (!br_multicast_select_querier(brmctx, pmctx, saddr))
 		return;
 
 	br_multicast_update_query_timer(brmctx, query, max_delay);
@@ -3130,7 +3121,7 @@ br_ip6_multicast_query_received(struct net_bridge_mcast
*brmctx,
 				struct br_ip *saddr,
 				unsigned long max_delay)
 {
-	if (!br_ip6_multicast_select_querier(brmctx, pmctx, saddr))
+	if (!br_multicast_select_querier(brmctx, pmctx, saddr))
 		return;
 
 	br_multicast_update_query_timer(brmctx, query, max_delay);
-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 15:00 UTC

head link

[Bridge] [PATCH net-next 4/6] net: bridge: mcast: dump ipv4 querier state

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Add support for dumping global IPv4 querier state, we dump the state
only if our own querier is enabled or there has been another external
querier which has won the election. For the bridge global state we use
a new attribute IFLA_BR_MCAST_QUERIER_STATE and embed the state inside.
The structure is:
 [IFLA_BR_MCAST_QUERIER_STATE]
  `[BRIDGE_QUERIER_IP_ADDRESS] - ip address of the querier
  `[BRIDGE_QUERIER_IP_PORT]    - bridge port ifindex where the querier was
                                 seen (set only if external querier)
  `[BRIDGE_QUERIER_IP_OTHER_TIMER]   -  other querier timeout

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 include/uapi/linux/if_bridge.h | 10 +++++
 include/uapi/linux/if_link.h   |  1 +
 net/bridge/br_multicast.c      | 73 ++++++++++++++++++++++++++++++++++
 net/bridge/br_netlink.c        |  5 ++-
 net/bridge/br_private.h        |  4 ++
 5 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 620d86e825b8..e0fff67fcd88 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -770,4 +770,14 @@ struct br_boolopt_multi {
 	__u32 optval;
 	__u32 optmask;
 };
+
+enum {
+	BRIDGE_QUERIER_UNSPEC,
+	BRIDGE_QUERIER_IP_ADDRESS,
+	BRIDGE_QUERIER_IP_PORT,
+	BRIDGE_QUERIER_IP_OTHER_TIMER,
+	BRIDGE_QUERIER_PAD,
+	__BRIDGE_QUERIER_MAX
+};
+#define BRIDGE_QUERIER_MAX (__BRIDGE_QUERIER_MAX - 1)
 #endif /* _UAPI_LINUX_IF_BRIDGE_H */
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 5310003523ce..8aad65b69054 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -479,6 +479,7 @@ enum {
 	IFLA_BR_MCAST_MLD_VERSION,
 	IFLA_BR_VLAN_STATS_PER_PORT,
 	IFLA_BR_MULTI_BOOLOPT,
+	IFLA_BR_MCAST_QUERIER_STATE,
 	__IFLA_BR_MAX,
 };
 
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 3705b7ace62d..4513bc13b6d3 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2905,6 +2905,79 @@ static bool br_multicast_select_querier(struct
net_bridge_mcast *brmctx,
 	return true;
 }
 
+static struct net_bridge_port *
+__br_multicast_get_querier_port(struct net_bridge *br,
+				const struct bridge_mcast_querier *querier)
+{
+	int port_ifidx = READ_ONCE(querier->port_ifidx);
+	struct net_bridge_port *p;
+	struct net_device *dev;
+
+	if (port_ifidx == 0)
+		return NULL;
+
+	dev = dev_get_by_index_rcu(dev_net(br->dev), port_ifidx);
+	if (!dev)
+		return NULL;
+	p = br_port_get_rtnl_rcu(dev);
+	if (!p || p->br != br)
+		return NULL;
+
+	return p;
+}
+
+size_t br_multicast_querier_state_size(void)
+{
+	return nla_total_size(sizeof(0)) +      /* nest attribute */
+	       nla_total_size(sizeof(__be32)) + /* BRIDGE_QUERIER_IP_ADDRESS */
+	       nla_total_size(sizeof(int)) +    /* BRIDGE_QUERIER_IP_PORT */
+	       nla_total_size_64bit(sizeof(u64)); /* BRIDGE_QUERIER_IP_OTHER_TIMER */
+}
+
+/* protected by rtnl or rcu */
+int br_multicast_dump_querier_state(struct sk_buff *skb,
+				    const struct net_bridge_mcast *brmctx,
+				    int nest_attr)
+{
+	struct bridge_mcast_querier querier = {};
+	struct net_bridge_port *p;
+	struct nlattr *nest;
+
+	if (!brmctx->multicast_querier &&
+	    !timer_pending(&brmctx->ip4_other_query.timer))
+		return 0;
+
+	nest = nla_nest_start(skb, nest_attr);
+	if (!nest)
+		return -EMSGSIZE;
+
+	rcu_read_lock();
+	br_multicast_read_querier(&brmctx->ip4_querier, &querier);
+	if (nla_put_in_addr(skb, BRIDGE_QUERIER_IP_ADDRESS,
+			    querier.addr.src.ip4)) {
+		rcu_read_unlock();
+		goto out_err;
+	}
+
+	p = __br_multicast_get_querier_port(brmctx->br, &querier);
+	if (timer_pending(&brmctx->ip4_other_query.timer) &&
+	    (nla_put_u64_64bit(skb, BRIDGE_QUERIER_IP_OTHER_TIMER,
+			       br_timer_value(&brmctx->ip4_other_query.timer),
+			       BRIDGE_QUERIER_PAD) ||
+	     (p && nla_put_u32(skb, BRIDGE_QUERIER_IP_PORT,
p->dev->ifindex)))) {
+		rcu_read_unlock();
+		goto out_err;
+	}
+	rcu_read_unlock();
+	nla_nest_end(skb, nest);
+
+	return 0;
+
+out_err:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
+}
+
 static void
 br_multicast_update_query_timer(struct net_bridge_mcast *brmctx,
 				struct bridge_mcast_other_query *query,
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 8ae026fa2ad7..2f184ad8ae29 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1501,6 +1501,7 @@ static size_t br_get_size(const struct net_device *brdev)
 	       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 */
+	       br_multicast_querier_state_size() + /* IFLA_BR_MCAST_QUERIER_STATE */
 #endif
 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 	       nla_total_size(sizeof(u8)) +     /* IFLA_BR_NF_CALL_IPTABLES */
@@ -1587,7 +1588,9 @@ static int br_fill_info(struct sk_buff *skb, const struct
net_device *brdev)
 	    nla_put_u32(skb, IFLA_BR_MCAST_STARTUP_QUERY_CNT,
 			br->multicast_ctx.multicast_startup_query_count) ||
 	    nla_put_u8(skb, IFLA_BR_MCAST_IGMP_VERSION,
-		       br->multicast_ctx.multicast_igmp_version))
+		       br->multicast_ctx.multicast_igmp_version) ||
+	    br_multicast_dump_querier_state(skb, &br->multicast_ctx,
+					    IFLA_BR_MCAST_QUERIER_STATE))
 		return -EMSGSIZE;
 #if IS_ENABLED(CONFIG_IPV6)
 	if (nla_put_u8(skb, IFLA_BR_MCAST_MLD_VERSION,
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 6ca9519f18a3..e03fc4c5f283 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -948,6 +948,10 @@ int br_mdb_replay(struct net_device *br_dev, struct
net_device *dev,
 		  struct netlink_ext_ack *extack);
 int br_rports_fill_info(struct sk_buff *skb,
 			const struct net_bridge_mcast *brmctx);
+int br_multicast_dump_querier_state(struct sk_buff *skb,
+				    const struct net_bridge_mcast *brmctx,
+				    int nest_attr);
+size_t br_multicast_querier_state_size(void);
 
 static inline bool br_group_is_l2(const struct br_ip *group)
 {
-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 15:00 UTC

head link

[Bridge] [PATCH net-next 5/6] net: bridge: mcast: dump ipv6 querier state

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Add support for dumping global IPv6 querier state, we dump the state
only if our own querier is enabled or there has been another external
querier which has won the election. For the bridge global state we use
a new attribute IFLA_BR_MCAST_QUERIER_STATE and embed the state inside.
The structure is:
  [IFLA_BR_MCAST_QUERIER_STATE]
   `[BRIDGE_QUERIER_IPV6_ADDRESS] - ip address of the querier
   `[BRIDGE_QUERIER_IPV6_PORT]    - bridge port ifindex where the querier
                                    was seen (set only if external querier)
   `[BRIDGE_QUERIER_IPV6_OTHER_TIMER]   -  other querier timeout

IPv4 and IPv6 attributes are embedded at the same level of
IFLA_BR_MCAST_QUERIER_STATE. If we didn't dump anything we cancel the nest
and return.

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 include/uapi/linux/if_bridge.h |  3 +++
 net/bridge/br_multicast.c      | 36 ++++++++++++++++++++++++++++++----
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index e0fff67fcd88..eceaad200bf6 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -777,6 +777,9 @@ enum {
 	BRIDGE_QUERIER_IP_PORT,
 	BRIDGE_QUERIER_IP_OTHER_TIMER,
 	BRIDGE_QUERIER_PAD,
+	BRIDGE_QUERIER_IPV6_ADDRESS,
+	BRIDGE_QUERIER_IPV6_PORT,
+	BRIDGE_QUERIER_IPV6_OTHER_TIMER,
 	__BRIDGE_QUERIER_MAX
 };
 #define BRIDGE_QUERIER_MAX (__BRIDGE_QUERIER_MAX - 1)
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 4513bc13b6d3..0e5d6ba03457 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -2943,15 +2943,15 @@ int br_multicast_dump_querier_state(struct sk_buff *skb,
 	struct net_bridge_port *p;
 	struct nlattr *nest;
 
-	if (!brmctx->multicast_querier &&
-	    !timer_pending(&brmctx->ip4_other_query.timer))
-		return 0;
-
 	nest = nla_nest_start(skb, nest_attr);
 	if (!nest)
 		return -EMSGSIZE;
 
 	rcu_read_lock();
+	if (!brmctx->multicast_querier &&
+	    !timer_pending(&brmctx->ip4_other_query.timer))
+		goto out_v6;
+
 	br_multicast_read_querier(&brmctx->ip4_querier, &querier);
 	if (nla_put_in_addr(skb, BRIDGE_QUERIER_IP_ADDRESS,
 			    querier.addr.src.ip4)) {
@@ -2968,8 +2968,36 @@ int br_multicast_dump_querier_state(struct sk_buff *skb,
 		rcu_read_unlock();
 		goto out_err;
 	}
+
+out_v6:
+#if IS_ENABLED(CONFIG_IPV6)
+	if (!brmctx->multicast_querier &&
+	    !timer_pending(&brmctx->ip6_other_query.timer))
+		goto out;
+
+	br_multicast_read_querier(&brmctx->ip6_querier, &querier);
+	if (nla_put_in6_addr(skb, BRIDGE_QUERIER_IPV6_ADDRESS,
+			     &querier.addr.src.ip6)) {
+		rcu_read_unlock();
+		goto out_err;
+	}
+
+	p = __br_multicast_get_querier_port(brmctx->br, &querier);
+	if (timer_pending(&brmctx->ip6_other_query.timer) &&
+	    (nla_put_u64_64bit(skb, BRIDGE_QUERIER_IPV6_OTHER_TIMER,
+			       br_timer_value(&brmctx->ip6_other_query.timer),
+			       BRIDGE_QUERIER_PAD) ||
+	     (p && nla_put_u32(skb, BRIDGE_QUERIER_IPV6_PORT,
+			       p->dev->ifindex)))) {
+		rcu_read_unlock();
+		goto out_err;
+	}
+out:
+#endif
 	rcu_read_unlock();
 	nla_nest_end(skb, nest);
+	if (!nla_len(nest))
+		nla_nest_cancel(skb, nest);
 
 	return 0;
 
-- 
2.31.1

Nikolay Aleksandrov

2021-Aug-13 15:00 UTC

head link

[Bridge] [PATCH net-next 6/6] net: bridge: vlan: dump mcast ctx querier state

From: Nikolay Aleksandrov <nikolay at nvidia.com>

Use the new mcast querier state dump infrastructure and export vlans'
mcast context querier state embedded in attribute
BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE.

Signed-off-by: Nikolay Aleksandrov <nikolay at nvidia.com>
---
 include/uapi/linux/if_bridge.h | 1 +
 net/bridge/br_vlan_options.c   | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index eceaad200bf6..f71a81fdbbc6 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -563,6 +563,7 @@ enum {
 	BRIDGE_VLANDB_GOPTS_MCAST_QUERIER,
 	BRIDGE_VLANDB_GOPTS_MCAST_ROUTER,
 	BRIDGE_VLANDB_GOPTS_MCAST_ROUTER_PORTS,
+	BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE,
 	__BRIDGE_VLANDB_GOPTS_MAX
 };
 #define BRIDGE_VLANDB_GOPTS_MAX (__BRIDGE_VLANDB_GOPTS_MAX - 1)
diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c
index b4fd5fa441b7..49dec53a4a74 100644
--- a/net/bridge/br_vlan_options.c
+++ b/net/bridge/br_vlan_options.c
@@ -299,7 +299,9 @@ bool br_vlan_global_opts_fill(struct sk_buff *skb, u16 vid,
u16 vid_range,
 	    nla_put_u8(skb, BRIDGE_VLANDB_GOPTS_MCAST_QUERIER,
 		       v_opts->br_mcast_ctx.multicast_querier) ||
 	    nla_put_u8(skb, BRIDGE_VLANDB_GOPTS_MCAST_ROUTER,
-		       v_opts->br_mcast_ctx.multicast_router))
+		       v_opts->br_mcast_ctx.multicast_router) ||
+	    br_multicast_dump_querier_state(skb, &v_opts->br_mcast_ctx,
+					    BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE))
 		goto out_err;
 
 	clockval =
jiffies_to_clock_t(v_opts->br_mcast_ctx.multicast_last_member_interval);
@@ -379,6 +381,7 @@ static size_t rtnl_vlan_global_opts_nlmsg_size(void)
 		+ nla_total_size(sizeof(u64)) /*
BRIDGE_VLANDB_GOPTS_MCAST_STARTUP_QUERY_INTVL */
 		+ nla_total_size(sizeof(u8)) /* BRIDGE_VLANDB_GOPTS_MCAST_QUERIER */
 		+ nla_total_size(sizeof(u8)) /* BRIDGE_VLANDB_GOPTS_MCAST_ROUTER */
+		+ br_multicast_querier_state_size() /*
BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE */
 #endif
 		+ nla_total_size(sizeof(u16)); /* BRIDGE_VLANDB_GOPTS_RANGE */
 }
-- 
2.31.1

patchwork-bot+netdevbpf at kernel.org

2021-Aug-14 13:10 UTC

head link

[Bridge] [PATCH net-next 0/6] net: bridge: mcast: dump querier state

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Fri, 13 Aug 2021 17:59:56 +0300 you wrote:> From: Nikolay Aleksandrov <nikolay at nvidia.com>
> 
> Hi,
> This set adds the ability to dump the current multicast querier state.
> This is extremely useful when debugging multicast issues, we've had
> many cases of unexpected queriers causing strange behaviour and mcast
> test failures. The first patch changes the querier struct to record
> a port device's ifindex instead of a pointer to the port itself so we
> can later retrieve it, I chose this way because it's much simpler
> and doesn't require us to do querier port ref counting, it is best
> effort anyway. Then patch 02 makes the querier address/port updates
> consistent via a combination of multicast_lock and seqcount, so readers
> can only use seqcount to get a consistent snapshot of address and port.
> Patch 03 is a minor cleanup in preparation for the dump support, it
> consolidates IPv4 and IPv6 querier selection paths as they share most of
> the logic (except address comparisons of course). Finally the last three
> patches add the new querier state dumping support, for the bridge's
> global multicast context we embed the BRIDGE_QUERIER_xxx attributes
> into IFLA_BR_MCAST_QUERIER_STATE and for the per-vlan global mcast
> contexts we embed them into BRIDGE_VLANDB_GOPTS_MCAST_QUERIER_STATE.
> 
> [...]
Here is the summary with links:
  - [net-next,1/6] net: bridge: mcast: record querier port device ifindex
instead of pointer
    https://git.kernel.org/netdev/net-next/c/bb18ef8e7e18
  - [net-next,2/6] net: bridge: mcast: make sure querier port/address updates
are consistent
    https://git.kernel.org/netdev/net-next/c/67b746f94ff3
  - [net-next,3/6] net: bridge: mcast: consolidate querier selection for ipv4
and ipv6
    https://git.kernel.org/netdev/net-next/c/c3fb3698f935
  - [net-next,4/6] net: bridge: mcast: dump ipv4 querier state
    https://git.kernel.org/netdev/net-next/c/c7fa1d9b1fb1
  - [net-next,5/6] net: bridge: mcast: dump ipv6 querier state
    https://git.kernel.org/netdev/net-next/c/85b410821174
  - [net-next,6/6] net: bridge: vlan: dump mcast ctx querier state
    https://git.kernel.org/netdev/net-next/c/ddc649d158c5

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Linux Ethernet Bridging - Aug 2021 - [Bridge] [PATCH net-next 2/6] net: bridge: mcast: make sure querier port/address updates are consistent

[Bridge] [PATCH net-next 0/6] net: bridge: mcast: dump querier state

[Bridge] [PATCH net-next 1/6] net: bridge: mcast: record querier port device ifindex instead of pointer

[Bridge] [PATCH net-next 2/6] net: bridge: mcast: make sure querier port/address updates are consistent

[Bridge] [PATCH net-next 3/6] net: bridge: mcast: consolidate querier selection for ipv4 and ipv6

[Bridge] [PATCH net-next 4/6] net: bridge: mcast: dump ipv4 querier state

[Bridge] [PATCH net-next 5/6] net: bridge: mcast: dump ipv6 querier state

[Bridge] [PATCH net-next 6/6] net: bridge: vlan: dump mcast ctx querier state

[Bridge] [PATCH net-next 0/6] net: bridge: mcast: dump querier state