netdev - [PATCH net-next v2 7/8] net: bridge: fdb: add support for flush filtering based on ndm flags and state

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Message-Id: <20220411172934.1813604-8-razor@blackwall.org>
Date:   Mon, 11 Apr 2022 20:29:33 +0300
From:   Nikolay Aleksandrov <razor@...ckwall.org>
To:     netdev@...r.kernel.org
Cc:     roopa@...dia.com, idosch@...sch.org, kuba@...nel.org,
        davem@...emloft.net, bridge@...ts.linux-foundation.org,
        Nikolay Aleksandrov <razor@...ckwall.org>
Subject: [PATCH net-next v2 7/8] net: bridge: fdb: add support for flush filtering based on ndm flags and state

Add support for fdb flush filtering based on ndm flags and state. NDM
state and flags are mapped to bridge-specific flags and matched
according to the specified masks. NTF_USE is used to represent
added_by_user flag since it sets it on fdb add and we don't have a 1:1
mapping for it. Only allowed bits can be set, NTF_USE and NTF_MASTER are
ignored.

Signed-off-by: Nikolay Aleksandrov <razor@...ckwall.org>
---
v2: ignore NTF_USE/NTF_MASTER and reject unknown flags

 net/bridge/br_fdb.c     | 58 ++++++++++++++++++++++++++++++++++++++---
 net/bridge/br_private.h |  5 ++++
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 045eb61e833e..2cea03cbc55f 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -594,13 +594,40 @@ void __br_fdb_flush(struct net_bridge *br,
 	rcu_read_unlock();
 }
 
+static unsigned long __ndm_state_to_fdb_flags(u16 ndm_state)
+{
+	unsigned long flags = 0;
+
+	if (ndm_state & NUD_PERMANENT)
+		__set_bit(BR_FDB_LOCAL, &flags);
+	if (ndm_state & NUD_NOARP)
+		__set_bit(BR_FDB_STATIC, &flags);
+
+	return flags;
+}
+
+static unsigned long __ndm_flags_to_fdb_flags(u8 ndm_flags)
+{
+	unsigned long flags = 0;
+
+	if (ndm_flags & NTF_USE)
+		__set_bit(BR_FDB_ADDED_BY_USER, &flags);
+	if (ndm_flags & NTF_EXT_LEARNED)
+		__set_bit(BR_FDB_ADDED_BY_EXT_LEARN, &flags);
+	if (ndm_flags & NTF_OFFLOADED)
+		__set_bit(BR_FDB_OFFLOADED, &flags);
+	if (ndm_flags & NTF_STICKY)
+		__set_bit(BR_FDB_STICKY, &flags);
+
+	return flags;
+}
+
 int br_fdb_flush(struct ndmsg *ndm, struct nlattr *tb[],
 		 struct net_device *dev, u16 vid,
 		 struct netlink_ext_ack *extack)
 {
-	struct net_bridge_fdb_flush_desc desc = {
-		.flags_mask = BR_FDB_STATIC
-	};
+	u8 ndm_flags = ndm->ndm_flags & ~FDB_FLUSH_IGNORED_NDM_FLAGS;
+	struct net_bridge_fdb_flush_desc desc = {};
 	struct net_bridge *br;
 
 	if (netif_is_bridge_master(dev)) {
@@ -615,6 +642,31 @@ int br_fdb_flush(struct ndmsg *ndm, struct nlattr *tb[],
 		br = p->br;
 	}
 
+	if (ndm_flags & ~FDB_FLUSH_ALLOWED_NDM_FLAGS) {
+		NL_SET_ERR_MSG(extack, "Unsupported fdb flush ndm flag bits set");
+		return -EINVAL;
+	}
+	if (ndm->ndm_state & ~FDB_FLUSH_ALLOWED_NDM_STATES) {
+		NL_SET_ERR_MSG(extack, "Unsupported fdb flush ndm state bits set");
+		return -EINVAL;
+	}
+
+	desc.flags |= __ndm_state_to_fdb_flags(ndm->ndm_state);
+	desc.flags |= __ndm_flags_to_fdb_flags(ndm_flags);
+	if (tb[NDFA_NDM_STATE_MASK]) {
+		u16 ndm_state_mask = nla_get_u16(tb[NDFA_NDM_STATE_MASK]);
+
+		desc.flags_mask |= __ndm_state_to_fdb_flags(ndm_state_mask);
+	}
+	if (tb[NDFA_NDM_FLAGS_MASK]) {
+		u8 ndm_flags_mask = nla_get_u8(tb[NDFA_NDM_FLAGS_MASK]);
+
+		desc.flags_mask |= __ndm_flags_to_fdb_flags(ndm_flags_mask);
+	}
+
+	br_debug(br, "flushing port ifindex: %d vlan id: %u flags: 0x%lx flags mask: 0x%lx\n",
+		 desc.port_ifindex, desc.vlan_id, desc.flags, desc.flags_mask);
+
 	__br_fdb_flush(br, &desc);
 
 	return 0;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 9fb9abdbd3f4..fd5cbd00e12d 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -762,6 +762,11 @@ static inline void br_netpoll_disable(struct net_bridge_port *p)
 #endif
 
 /* br_fdb.c */
+#define FDB_FLUSH_IGNORED_NDM_FLAGS (NTF_MASTER | NTF_SELF)
+#define FDB_FLUSH_ALLOWED_NDM_STATES (NUD_PERMANENT | NUD_NOARP)
+#define FDB_FLUSH_ALLOWED_NDM_FLAGS (NTF_USE | NTF_EXT_LEARNED | \
+				     NTF_STICKY | NTF_OFFLOADED)
+
 int br_fdb_init(void);
 void br_fdb_fini(void);
 int br_fdb_hash_init(struct net_bridge *br);
-- 
2.35.1