On Wed, Mar 02, 2022 at 00:19, Nikolay Aleksandrov [off-list ref] wrote:

On 1 March 2022 11:03:14 CET, Tobias Waldekranz [off-list ref] wrote:

quoted

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.

quoted

	__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?