On 10/03/2022 18:11, Hans Schultz wrote:
On tor, mar 10, 2022 at 17:57, Nikolay Aleksandrov <[email protected]> wrote:
On 10/03/2022 17:38, Hans Schultz wrote:
On tor, mar 10, 2022 at 16:42, Nikolay Aleksandrov <[email protected]> wrote:
On 10/03/2022 16:23, Hans Schultz wrote:
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 <[email protected]>
---
    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..

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.
    #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.


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


        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...

        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!

+                               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 {

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