On mån, mar 14, 2022 at 17:30, Ido Schimmel <idosch@xxxxxxxxxx> wrote:
> On Thu, Mar 10, 2022 at 03:23:18PM +0100, 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
>> };
>> #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;
>> +
>> 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;
>> 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) {
>> + set_bit(BR_FDB_ENTRY_LOCKED, &flags);
>
> This flag is read-only for user space, right? That is, the kernel needs
> to reject it during netlink policy validation.
>
Yes, the flag is only readable from user space, unless there is a wish
to change that.
>> + br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, flags);
>> + }
>> goto drop;
>> + } else {
>
> IIUC, we get here in case there is a non-local FDB entry with the SA
> that points to our port. Can you write it as:
>
Yes, looks like that's more optimal. :)
> if (!fdb_src || READ_ONCE(fdb_src->dst) != p ||
> test_bit(BR_FDB_LOCAL, &fdb_src->flags) ||
> test_bit(BR_FDB_ENTRY_LOCKED, &fdb_src->flags)) {
> if (!fdb_src) {
> ...
> }
> goto drop;
> }
>
>> + 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 {
>> --
>> 2.30.2
>>
