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

From: Nikolay Aleksandrov
Date: Tue Mar 01 2022 - 18:19:19 EST


On 1 March 2022 11:03:14 CET, Tobias Waldekranz <tobias@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
>---
> 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

>+ nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
>+ RTM_GETMST, sizeof(*bpm), NLM_F_MULTI);
>+ if (!nlh)
>+ return -EMSGSIZE;
>+
>+ bpm = nlmsg_data(nlh);
>+ memset(bpm, 0, sizeof(*bpm));
>+ bpm->ifindex = p->dev->ifindex;
>+
>+ seen = bitmap_zalloc(VLAN_N_VID, 0);
>+ if (!seen)
>+ return -ENOMEM;
>+
>+ list_for_each_entry(v, &vg->vlan_list, vlist) {
>+ if (test_bit(v->brvlan->msti, seen))
>+ continue;
>+
>+ if (idx < s_idx)
>+ goto skip;
>+
>+ nest = nla_nest_start_noflag(skb, BRIDGE_MST_ENTRY);
>+ if (!nest ||
>+ nla_put_u16(skb, BRIDGE_MST_ENTRY_MSTI, v->brvlan->msti) ||
>+ nla_put_u8(skb, BRIDGE_MST_ENTRY_STATE, v->state)) {
>+ err = -EMSGSIZE;
>+ break;
>+ }
>+ nla_nest_end(skb, nest);
>+
>+ set_bit(v->brvlan->msti, seen);
>+skip:
>+ idx++;
>+ }
>+
>+ kfree(seen);
>+ nlmsg_end(skb, nlh);
>+ return err;
>+}
>+
>+static struct net_bridge_port *br_mst_nl_get_parse(struct net *net,
>+ struct netlink_callback *cb)
>+{
>+ struct netlink_ext_ack *extack = cb->extack;
>+ const struct nlmsghdr *nlh = cb->nlh;
>+ struct net_bridge_port *p;
>+ struct br_port_msg *bpm;
>+ struct net_device *dev;
>+
>+ if (nlh->nlmsg_len < nlmsg_msg_size(sizeof(*bpm))) {
>+ NL_SET_ERR_MSG_MOD(extack, "Invalid header for mst get request");
>+ return ERR_PTR(-EINVAL);
>+ }
>+
>+ if (nlmsg_attrlen(nlh, sizeof(*bpm))) {
>+ NL_SET_ERR_MSG(extack, "Invalid data after header in mst get request");
>+ return ERR_PTR(-EINVAL);
>+ }
>+
>+ bpm = nlmsg_data(nlh);
>+ if (!bpm->ifindex)
>+ return NULL;
>+
>+ dev = __dev_get_by_index(net, bpm->ifindex);
>+ if (!dev)
>+ return ERR_PTR(-ENODEV);
>+
>+ if (!netif_is_bridge_port(dev)) {
>+ NL_SET_ERR_MSG_MOD(extack, "The device is not a valid bridge port");
>+ return ERR_PTR(-EINVAL);
>+ }
>+
>+ p = br_port_get_rtnl(dev);
>+ if (WARN_ON(!p))
>+ return ERR_PTR(-ENODEV);
>+
>+ if (!br_opt_get(p->br, BROPT_MST_ENABLED)) {
>+ NL_SET_ERR_MSG_MOD(extack, "Can't query MST state when MST is disabled");
>+ return ERR_PTR(-EINVAL);
>+ }
>+
>+ return p;
>+}
>+
>+static int br_mst_nl_get(struct sk_buff *skb, struct netlink_callback *cb)
>+{
>+ int err = 0, idx = 0, s_idx = cb->args[0];
>+ struct net *net = sock_net(skb->sk);
>+ struct net_bridge_port *p;
>+ struct net_device *dev;
>+
>+ p = br_mst_nl_get_parse(net, cb);
>+ if (IS_ERR(p))
>+ return PTR_ERR(p);
>+
>+ if (p) {
>+ err = br_mst_nl_get_one(p, skb, cb);
>+ if (err != -EMSGSIZE)
>+ return err;
>+ } else {
>+ for_each_netdev(net, dev) {
>+ if (!netif_is_bridge_port(dev))
>+ continue;
>+
>+ if (idx < s_idx)
>+ goto skip;
>+
>+ p = br_port_get_rtnl(dev);
>+ if (WARN_ON(!p))
>+ return -ENODEV;
>+
>+ err = br_mst_nl_get_one(p, skb, cb);
>+ if (err == -EMSGSIZE)
>+ break;
>+skip:
>+ idx++;
>+ }
>+ }
>+
>+ cb->args[0] = idx;
>+ return skb->len;
>+}
>+
>+static const struct nla_policy br_mst_nl_policy[BRIDGE_MST_ENTRY_MAX + 1] = {
>+ [BRIDGE_MST_ENTRY_MSTI] = NLA_POLICY_RANGE(NLA_U16,
>+ 1, /* 0 reserved for CST */
>+ VLAN_N_VID - 1),
>+ [BRIDGE_MST_ENTRY_STATE] = NLA_POLICY_RANGE(NLA_U8,
>+ BR_STATE_DISABLED,
>+ BR_STATE_BLOCKING),
>+};
>+
>+static int br_mst_nl_set_one(struct net_bridge_port *p,
>+ const struct nlattr *attr,
>+ struct netlink_ext_ack *extack)
>+{
>+ struct nlattr *tb[BRIDGE_MST_ENTRY_MAX + 1];
>+ u16 msti;
>+ u8 state;
>+ int err;
>+
>+ err = nla_parse_nested(tb, BRIDGE_MST_ENTRY_MAX, attr,
>+ br_mst_nl_policy, extack);
>+ if (err)
>+ return err;
>+
>+ if (!tb[BRIDGE_MST_ENTRY_MSTI]) {
>+ NL_SET_ERR_MSG_MOD(extack, "MSTI not specified");
>+ return -EINVAL;
>+ }
>+
>+ if (!tb[BRIDGE_MST_ENTRY_STATE]) {
>+ NL_SET_ERR_MSG_MOD(extack, "State not specified");
>+ return -EINVAL;
>+ }
>+
>+ msti = nla_get_u16(tb[BRIDGE_MST_ENTRY_MSTI]);
>+ state = nla_get_u8(tb[BRIDGE_MST_ENTRY_STATE]);
>+
>+ br_mst_set_state(p, msti, state);
>+ return 0;
>+}
>+
>+static int br_mst_nl_set(struct sk_buff *skb, struct nlmsghdr *nlh,
>+ struct netlink_ext_ack *extack)
>+{
>+ struct net *net = sock_net(skb->sk);
>+ struct net_bridge_port *p;
>+ struct br_port_msg *bpm;
>+ struct net_device *dev;
>+ struct nlattr *attr;
>+ int err, msts = 0;
>+ int rem;
>+
>+ err = nlmsg_parse(nlh, sizeof(*bpm), NULL, BRIDGE_MST_MAX, NULL,
>+ extack);
>+ if (err < 0)
>+ return err;
>+
>+ bpm = nlmsg_data(nlh);
>+ dev = __dev_get_by_index(net, bpm->ifindex);
>+ if (!dev)
>+ return -ENODEV;
>+
>+ if (!netif_is_bridge_port(dev)) {
>+ NL_SET_ERR_MSG_MOD(extack, "The device is not a valid bridge port");
>+ return -EINVAL;
>+ }
>+
>+ p = br_port_get_rtnl(dev);
>+ if (WARN_ON(!p))
>+ return -ENODEV;
>+
>+ if (!br_opt_get(p->br, BROPT_MST_ENABLED)) {
>+ NL_SET_ERR_MSG_MOD(extack, "Can't modify MST state when MST is disabled");
>+ return -EBUSY;
>+ }
>+
>+ nlmsg_for_each_attr(attr, nlh, sizeof(*bpm), rem) {
>+ switch (nla_type(attr)) {
>+ case BRIDGE_MST_ENTRY:
>+ err = br_mst_nl_set_one(p, attr, extack);
>+ break;
>+ default:
>+ continue;
>+ }
>+
>+ msts++;
>+ if (err)
>+ break;
>+ }
>+
>+ if (!msts) {
>+ NL_SET_ERR_MSG_MOD(extack, "Found no MST entries to process");
>+ err = -EINVAL;
>+ }
>+
>+ return err;
>+}
>+
>+void br_mst_rtnl_init(void)
>+{
>+ rtnl_register_module(THIS_MODULE, PF_BRIDGE, RTM_GETMST, NULL,
>+ br_mst_nl_get, 0);
>+ rtnl_register_module(THIS_MODULE, PF_BRIDGE, RTM_SETMST,
>+ br_mst_nl_set, NULL, 0);
>+}
>+
>+void br_mst_rtnl_uninit(void)
>+{
>+ rtnl_unregister(PF_BRIDGE, RTM_SETMST);
>+ rtnl_unregister(PF_BRIDGE, RTM_GETMST);
>+}
>diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
>index a17a0fe25a58..6d70d6f9cf17 100644
>--- a/net/bridge/br_netlink.c
>+++ b/net/bridge/br_netlink.c
>@@ -1813,6 +1813,7 @@ int __init br_netlink_init(void)
>
> br_mdb_init();
> br_vlan_rtnl_init();
>+ br_mst_rtnl_init();
> rtnl_af_register(&br_af_ops);
>
> err = rtnl_link_register(&br_link_ops);
>@@ -1824,6 +1825,7 @@ int __init br_netlink_init(void)
> out_af:
> rtnl_af_unregister(&br_af_ops);
> br_mdb_uninit();
>+ br_mst_rtnl_uninit();
> return err;
> }
>
>@@ -1831,6 +1833,7 @@ void br_netlink_fini(void)
> {
> br_mdb_uninit();
> br_vlan_rtnl_uninit();
>+ br_mst_rtnl_uninit();
> rtnl_af_unregister(&br_af_ops);
> rtnl_link_unregister(&br_link_ops);
> }
>diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
>index 63601043abca..7882a65ffb43 100644
>--- a/net/bridge/br_private.h
>+++ b/net/bridge/br_private.h
>@@ -1782,6 +1782,8 @@ void br_mst_set_state(struct net_bridge_port *p, u16 msti, u8 state);
> int br_mst_vlan_set_msti(struct net_bridge_vlan *v, u16 msti);
> void br_mst_vlan_init_state(struct net_bridge_vlan *v);
> int br_mst_set_enabled(struct net_bridge *br, unsigned long val);
>+void br_mst_rtnl_init(void);
>+void br_mst_rtnl_uninit(void);
> #else
> static inline bool br_mst_is_enabled(struct net_bridge *br)
> {
>@@ -1790,6 +1792,8 @@ static inline bool br_mst_is_enabled(struct net_bridge *br)
>
> static inline void br_mst_set_state(struct net_bridge_port *p,
> u16 msti, u8 state) {}
>+static inline void br_mst_rtnl_init(void) {}
>+static inline void br_mst_rtnl_uninit(void) {}
> #endif
>
> struct nf_br_ops {