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

[Tobias Waldekranz <tobias@waldekranz.com>]

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?