On 10/03/2022 18:11, Hans Schultz wrote:

On tor, mar 10, 2022 at 17:57, Nikolay Aleksandrov [off-list ref] wrote:

quoted

On 10/03/2022 17:38, Hans Schultz wrote:

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On tor, mar 10, 2022 at 16:42, Nikolay Aleksandrov [off-list ref] wrote:

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On 10/03/2022 16:23, Hans Schultz wrote:

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Add an intermediate state for clients behind a locked port to allow for
possible opening of the port for said clients. This feature corresponds
to the Mac-Auth and MAC Authentication Bypass (MAB) named features. The
latter defined by Cisco.

Signed-off-by: Hans Schultz <redacted>
---
    include/uapi/linux/neighbour.h |  1 +
    net/bridge/br_fdb.c            |  6 ++++++
    net/bridge/br_input.c          | 11 ++++++++++-
    net/bridge/br_private.h        |  3 ++-
    4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/neighbour.h b/include/uapi/linux/neighbour.h
index db05fb55055e..83115a592d58 100644
--- a/include/uapi/linux/neighbour.h
+++ b/include/uapi/linux/neighbour.h

@@ -208,6 +208,7 @@ enum {
    	NFEA_UNSPEC,
    	NFEA_ACTIVITY_NOTIFY,
    	NFEA_DONT_REFRESH,
+	NFEA_LOCKED,
    	__NFEA_MAX
    };

Hmm, can you use NDA_FLAGS_EXT instead ?
That should simplify things and reduce the nl size.

I am using NDA_FDB_EXT_ATTRS. NFEA_LOCKED is just the
flag as the other flags section is full wrt the normal flags, but maybe it
doesn't fit in that section?

Actually wait a second, this is completely wrong use of NDA_FDB_EXT_ATTRS.
That is a nested attribute, so the code below is wrong. More below..

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I will just note that iproute2 support for parsing nested attributes
does not work, thus the BR_FDB_NOTIFY section (lines 150-165) are
obsolete with respect to iproute2 as it is now. I cannot rule out that
someone has some other tool that can handle this BR_FDB_NOTIFY, but I
could not make iproute2 as it stands handle nested attributes. And of
course there is no handling of NDA_FDB_EXT_ATTRS in iproute2 now.

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    #define NFEA_MAX (__NFEA_MAX - 1)

diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 6ccda68bd473..396dcf3084cf 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c

@@ -105,6 +105,7 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
    	struct nda_cacheinfo ci;
    	struct nlmsghdr *nlh;
    	struct ndmsg *ndm;
+	u8 ext_flags = 0;
    
    	nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
    	if (nlh == NULL)

@@ -125,11 +126,16 @@ static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
    		ndm->ndm_flags |= NTF_EXT_LEARNED;
    	if (test_bit(BR_FDB_STICKY, &fdb->flags))
    		ndm->ndm_flags |= NTF_STICKY;
+	if (test_bit(BR_FDB_ENTRY_LOCKED, &fdb->flags))
+		ext_flags |= 1 << NFEA_LOCKED;
    
    	if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->key.addr))
    		goto nla_put_failure;
    	if (nla_put_u32(skb, NDA_MASTER, br->dev->ifindex))
    		goto nla_put_failure;
+	if (nla_put_u8(skb, NDA_FDB_EXT_ATTRS, ext_flags))
+		goto nla_put_failure;
+

This is wrong. NDA_FDB_EXT_ATTRS is a nested attribute, you can't use it as a u8.
You need to have this structure:
   [ NDA_FDB_EXT_ATTRS ]
    ` [ NFEA_LOCKED ]

But that's why I asked if you could use the NDA_FLAGS_EXT attribute. You can see
the logic from the neigh code.

Ahh yes, NDA_FLAGS_EXT was not there in the 5.15.x kernel I have
originally being making the patches in.

I hope that the handling of nested attributes has been fixed in
iproute2. ;-)

It hasn't been broken, I'm guessing you're having issues with the nested bit being set.
Check NLA_F_NESTED and NLA_TYPE_MASK.

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Also note that you need to account for the new attribute's size in fdb_nlmsg_size().

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    	ci.ndm_used	 = jiffies_to_clock_t(now - fdb->used);
    	ci.ndm_confirmed = 0;
    	ci.ndm_updated	 = jiffies_to_clock_t(now - fdb->updated);

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index e0c13fcc50ed..897908484b18 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c

@@ -75,6 +75,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
    	struct net_bridge_mcast *brmctx;
    	struct net_bridge_vlan *vlan;
    	struct net_bridge *br;
+	unsigned long flags = 0;

Please move this below...

quoted

    	u16 vid = 0;
    	u8 state;
    

@@ -94,8 +95,16 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
    			br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
    
    		if (!fdb_src || READ_ONCE(fdb_src->dst) != p ||
-		    test_bit(BR_FDB_LOCAL, &fdb_src->flags))
+		    test_bit(BR_FDB_LOCAL, &fdb_src->flags)) {
+			if (!fdb_src) {

... here where it's only used.

Forgot that one. Shall do!

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+				set_bit(BR_FDB_ENTRY_LOCKED, &flags);
+				br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, flags);
+			}
    			goto drop;
+		} else {
+			if (test_bit(BR_FDB_ENTRY_LOCKED, &fdb_src->flags))
+				goto drop;
+		}
    	}
    
    	nbp_switchdev_frame_mark(p, skb);

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 48bc61ebc211..f5a0b68c4857 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h

@@ -248,7 +248,8 @@ enum {
    	BR_FDB_ADDED_BY_EXT_LEARN,
    	BR_FDB_OFFLOADED,
    	BR_FDB_NOTIFY,
-	BR_FDB_NOTIFY_INACTIVE
+	BR_FDB_NOTIFY_INACTIVE,
+	BR_FDB_ENTRY_LOCKED,
    };
    
    struct net_bridge_fdb_key {