Re: [PATCH net-next 1/3] net: bridge: add fdb flag to extent locked port feature
From: Nikolay Aleksandrov
Date: Thu Mar 10 2022 - 10:57:39 EST
On 10/03/2022 17:38, Hans Schultz wrote:
On tor, mar 10, 2022 at 16:42, Nikolay Aleksandrov <razor@xxxxxxxxxxxxx> 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 <schultz.hans+netdev@xxxxxxxxx>
---
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.
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 {