Re: [PATCH v2 net-next 03/10] net: bridge: mst: Support setting and reporting MST port states

[Nikolay Aleksandrov <razor@blackwall.org>]

On 07/03/2022 17:00, Tobias Waldekranz wrote:
> On Wed, Mar 02, 2022 at 00:19, Nikolay Aleksandrov <razor@blackwall.org> wrote:
>> On 1 March 2022 11:03:14 CET, Tobias Waldekranz <tobias@waldekranz.com> wrote:
>>> Make it possible to change the port state in a given MSTI. This is
>>> done through a new netlink interface, since the MSTIs are objects in
>>> their own right. The proposed iproute2 interface would be:
>>>
>>>    bridge mst set dev <PORT> msti <MSTI> state <STATE>
>>>
>>> Current states in all applicable MSTIs can also be dumped. The
>>> proposed iproute interface looks like this:
>>>
>>> $ bridge mst
>>> port              msti
>>> vb1               0
>>> 		    state forwarding
>>> 		  100
>>> 		    state disabled
>>> vb2               0
>>> 		    state forwarding
>>> 		  100
>>> 		    state forwarding
>>>
>>> The preexisting per-VLAN states are still valid in the MST
>>> mode (although they are read-only), and can be queried as usual if one
>>> is interested in knowing a particular VLAN's state without having to
>>> care about the VID to MSTI mapping (in this example VLAN 20 and 30 are
>>> bound to MSTI 100):
>>>
>>> $ bridge -d vlan
>>> port              vlan-id
>>> vb1               10
>>> 		    state forwarding mcast_router 1
>>> 		  20
>>> 		    state disabled mcast_router 1
>>> 		  30
>>> 		    state disabled mcast_router 1
>>> 		  40
>>> 		    state forwarding mcast_router 1
>>> vb2               10
>>> 		    state forwarding mcast_router 1
>>> 		  20
>>> 		    state forwarding mcast_router 1
>>> 		  30
>>> 		    state forwarding mcast_router 1
>>> 		  40
>>> 		    state forwarding mcast_router 1
>>>
>>> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
>>> ---
>>> include/uapi/linux/if_bridge.h |  16 +++
>>> include/uapi/linux/rtnetlink.h |   5 +
>>> net/bridge/br_mst.c            | 244 +++++++++++++++++++++++++++++++++
>>> net/bridge/br_netlink.c        |   3 +
>>> net/bridge/br_private.h        |   4 +
>>> 5 files changed, 272 insertions(+)
>>>
>>> diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
>>> index b68016f625b7..784482527861 100644
>>> --- a/include/uapi/linux/if_bridge.h
>>> +++ b/include/uapi/linux/if_bridge.h
>>> @@ -785,4 +785,20 @@ enum {
>>> 	__BRIDGE_QUERIER_MAX
>>> };
>>> #define BRIDGE_QUERIER_MAX (__BRIDGE_QUERIER_MAX - 1)
>>> +
>>> +enum {
>>> +	BRIDGE_MST_UNSPEC,
>>> +	BRIDGE_MST_ENTRY,
>>> +	__BRIDGE_MST_MAX,
>>> +};
>>> +#define BRIDGE_MST_MAX (__BRIDGE_MST_MAX - 1)
>>> +
>>> +enum {
>>> +	BRIDGE_MST_ENTRY_UNSPEC,
>>> +	BRIDGE_MST_ENTRY_MSTI,
>>> +	BRIDGE_MST_ENTRY_STATE,
>>> +	__BRIDGE_MST_ENTRY_MAX,
>>> +};
>>> +#define BRIDGE_MST_ENTRY_MAX (__BRIDGE_MST_ENTRY_MAX - 1)
>>> +
>>> #endif /* _UAPI_LINUX_IF_BRIDGE_H */
>>> diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
>>> index 0970cb4b1b88..4a48f3ce862c 100644
>>> --- a/include/uapi/linux/rtnetlink.h
>>> +++ b/include/uapi/linux/rtnetlink.h
>>> @@ -192,6 +192,11 @@ enum {
>>> 	RTM_GETTUNNEL,
>>> #define RTM_GETTUNNEL	RTM_GETTUNNEL
>>>
>>> +	RTM_GETMST = 124 + 2,
>>> +#define RTM_GETMST	RTM_GETMST
>>> +	RTM_SETMST,
>>> +#define RTM_SETMST	RTM_SETMST
>>> +
>>
>> I think you should also update selinux  (see nlmsgtab.c)
>> I'll think about this one, if there is some nice way to avoid the new rtm types.
>>
>>> 	__RTM_MAX,
>>> #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
>>> };
>>> diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
>>> index f3b8e279b85c..8dea8e7257fd 100644
>>> --- a/net/bridge/br_mst.c
>>> +++ b/net/bridge/br_mst.c
>>> @@ -120,3 +120,247 @@ int br_mst_set_enabled(struct net_bridge *br, unsigned long val)
>>> 	br_opt_toggle(br, BROPT_MST_ENABLED, !!val);
>>> 	return 0;
>>> }
>>> +
>>> +static int br_mst_nl_get_one(struct net_bridge_port *p, struct sk_buff *skb,
>>> +			     struct netlink_callback *cb)
>>> +{
>>> +	struct net_bridge_vlan_group *vg = nbp_vlan_group(p);
>>> +	int err = 0, idx = 0, s_idx = cb->args[1];
>>> +	struct net_bridge_vlan *v;
>>> +	struct br_port_msg *bpm;
>>> +	struct nlmsghdr *nlh;
>>> +	struct nlattr *nest;
>>> +	unsigned long *seen;
>>> +
>>
>> Reverse xmas tree
> 
> Both of these lines end at the 28th column. Is there some other
> tiebreaking mechanism that forces the reverse ordering of nest and seen?
> 
> In a variable-width font, the nest declaration does appear shorter. I
> remember that you did not have your laptop with you, could that be it?

Ah yes, you're right. :) Sorry for the noise.