[RFC net-next Patch 3/3] net: bridge: mrp: Add netlink support to configure MRP

[Horatiu Vultur]

Extend br_netlink to be able to create/delete MRP instances. The current
configurations options for each instance are:
- set primary port
- set secondary port
- set MRP ring role (MRM or MRC)
- set MRP ring id.

To create a MRP instance on the bridge:
$ bridge mrp add dev br0 p_port eth0 s_port eth1 ring_role 2 ring_id 1

Where:
p_port, s_port: can be any port under the bridge
ring_role: can have the value 1(MRC - Media Redundancy Client) or
           2(MRM - Media Redundancy Manager). In a ring can be only one MRM.
ring_id: unique id for each MRP instance.

It is possible to create multiple instances. Each instance has to have it's own
ring_id and a port can't be part of multiple instances:
$ bridge mrp add dev br0 p_port eth2 s_port eth3 ring_role 1 ring_id 2

To see current MRP instances and their status:
$ bridge mrp show
dev br0 p_port eth2 s_port eth3 ring_role 1 ring_id 2 ring_state 3
dev br0 p_port eth0 s_port eth1 ring_role 2 ring_id 1 ring_state 4

Where:
p_port, s_port, ring_role, ring_id: represent the configuration values. It is
   possible for primary port to change the role with the secondary port.
   It depends on the states through which the node goes.
ring_state: depends on the ring_role. If mrp_ring_role is 1(MRC) then the values
   of mrp_ring_state can be: 0(AC_STAT1), 1(DE_IDLE), 2(PT), 3(DE), 4(PT_IDLE).
   If mrp_ring_role is 2(MRM) then the values of mrp_ring_state can be:
   0(AC_STAT1), 1(PRM_UP), 2(CHK_RO), 3(CHK_RC).

Signed-off-by: Horatiu Vultur <horatiu.vultur@xxxxxxxxxxxxx>
---
 include/uapi/linux/if_bridge.h |  27 ++++
 include/uapi/linux/rtnetlink.h |   7 +
 net/bridge/br_mrp.c            | 281 +++++++++++++++++++++++++++++++++
 net/bridge/br_netlink.c        |   9 ++
 net/bridge/br_private.h        |   2 +
 net/bridge/br_private_mrp.h    |   9 ++
 security/selinux/nlmsgtab.c    |   5 +-
 7 files changed, 339 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/if_bridge.h b/include/uapi/linux/if_bridge.h
index 4a58e3d7de46..00f4f465d62a 100644
--- a/include/uapi/linux/if_bridge.h
+++ b/include/uapi/linux/if_bridge.h
@@ -265,6 +265,33 @@ enum {
 };
 #define MDBA_SET_ENTRY_MAX (__MDBA_SET_ENTRY_MAX - 1)
 
+#ifdef CONFIG_BRIDGE_MRP
+enum {
+	MRPA_UNSPEC,
+	MRPA_MRP,
+	__MRPA_MAX,
+};
+#define MRPA_MAX (__MRPA_MAX - 1)
+
+enum {
+	MRPA_MRP_UNSPEC,
+	MRPA_MRP_ENTRY,
+	__MRPA_MRP_MAX,
+};
+#define MRPA_MRP_MAX (__MRPA_MRP_MAX - 1)
+
+enum {
+	MRP_ATTR_UNSPEC,
+	MRP_ATTR_P_IFINDEX,
+	MRP_ATTR_S_IFINDEX,
+	MRP_ATTR_RING_ROLE,
+	MRP_ATTR_RING_NR,
+	MRP_ATTR_RING_STATE,
+	__MRP_ATTR_MAX,
+};
+#define MRP_ATTR_MAX (__MRP_ATTR_MAX - 1)
+#endif
+
 /* Embedded inside LINK_XSTATS_TYPE_BRIDGE */
 enum {
 	BRIDGE_XSTATS_UNSPEC,
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 1418a8362bb7..b1d72a5309cd 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -171,6 +171,13 @@ enum {
 	RTM_GETLINKPROP,
 #define RTM_GETLINKPROP	RTM_GETLINKPROP
 
+	RTM_NEWMRP = 112,
+#define RTM_NEWMRP	RTM_NEWMRP
+	RTM_DELMRP,
+#define RTM_DELMRP	RTM_DELMRP
+	RTM_GETMRP,
+#define RTM_GETMRP	RTM_GETMRP
+
 	__RTM_MAX,
 #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
 };
diff --git a/net/bridge/br_mrp.c b/net/bridge/br_mrp.c
index a84aab3f7114..4173021d3bfa 100644
--- a/net/bridge/br_mrp.c
+++ b/net/bridge/br_mrp.c
@@ -1234,3 +1234,284 @@ void br_mrp_port_uninit(struct net_bridge_port *port)
 
 	mutex_unlock(&mrp->lock);
 }
+
+/* Do sanity checks and obtain device and the ring */
+static int br_mrp_parse(struct sk_buff *skb, struct nlmsghdr *nlh,
+			struct net_device **pdev, struct br_mrp_config *conf)
+{
+	struct nlattr *tb[MRP_ATTR_MAX + 1];
+	struct net *net = sock_net(skb->sk);
+	struct br_port_msg *bpm;
+	struct net_device *dev;
+	int err;
+
+	err = nlmsg_parse_deprecated(nlh, sizeof(*bpm), tb,
+				     MRP_ATTR_MAX, NULL, NULL);
+	if (err < 0)
+		return err;
+
+	bpm = nlmsg_data(nlh);
+	if (bpm->ifindex == 0) {
+		pr_info("PF_BRIDGE: %s with invalid ifindex\n", __func__);
+		return -EINVAL;
+	}
+
+	dev = __dev_get_by_index(net, bpm->ifindex);
+	if (!dev) {
+		pr_info("PF_BRIDGE: %s with unknown ifindex\n", __func__);
+		return -ENODEV;
+	}
+
+	if (!(dev->priv_flags & IFF_EBRIDGE)) {
+		pr_info("PF_BRIDGE: %s with non-bridge\n", __func__);
+		return -EOPNOTSUPP;
+	}
+
+	*pdev = dev;
+
+	if (tb[MRP_ATTR_P_IFINDEX])
+		conf->p_ifindex = nla_get_u32(tb[MRP_ATTR_P_IFINDEX]);
+	if (tb[MRP_ATTR_S_IFINDEX])
+		conf->s_ifindex = nla_get_u32(tb[MRP_ATTR_S_IFINDEX]);
+	if (tb[MRP_ATTR_RING_ROLE])
+		conf->ring_role = nla_get_u8(tb[MRP_ATTR_RING_ROLE]);
+	if (tb[MRP_ATTR_RING_NR])
+		conf->ring_nr = nla_get_u8(tb[MRP_ATTR_RING_NR]);
+
+	return 0;
+}
+
+static int br_mrp_fill_entry(struct sk_buff *skb, struct netlink_callback *cb,
+			     struct net_device *dev)
+{
+	int idx = 0, s_idx = cb->args[1], err = 0;
+	struct net_bridge *br = netdev_priv(dev);
+	struct br_mrp *mrp;
+	struct nlattr *nest, *nest2;
+
+	nest = nla_nest_start_noflag(skb, MRPA_MRP);
+	if (!nest)
+		return -EMSGSIZE;
+
+	list_for_each_entry_rcu(mrp, &br->mrp_list, list) {
+		if (idx < s_idx)
+			goto skip;
+
+		nest2 = nla_nest_start_noflag(skb, MRPA_MRP_ENTRY);
+		if (!nest2) {
+			err = -EMSGSIZE;
+			mutex_unlock(&mrp->lock);
+			break;
+		}
+
+		mutex_lock(&mrp->lock);
+
+		if (mrp->p_port)
+			nla_put_u32(skb, MRP_ATTR_P_IFINDEX,
+				    mrp->p_port->dev->ifindex);
+		if (mrp->s_port)
+			nla_put_u32(skb, MRP_ATTR_S_IFINDEX,
+				    mrp->s_port->dev->ifindex);
+
+		nla_put_u32(skb, MRP_ATTR_RING_NR, mrp->ring_nr);
+		nla_put_u32(skb, MRP_ATTR_RING_ROLE, mrp->ring_role);
+
+		if (mrp->ring_role == BR_MRP_RING_ROLE_MRM)
+			nla_put_u32(skb, MRP_ATTR_RING_STATE, mrp->mrm_state);
+		if (mrp->ring_role == BR_MRP_RING_ROLE_MRC)
+			nla_put_u32(skb, MRP_ATTR_RING_STATE, mrp->mrc_state);
+
+		mutex_unlock(&mrp->lock);
+
+		nla_nest_end(skb, nest2);
+skip:
+		idx++;
+	}
+
+	cb->args[1] = idx;
+	nla_nest_end(skb, nest);
+	return err;
+}
+
+static int br_mrp_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct nlmsghdr *nlh = NULL;
+	struct net_device *dev;
+	int idx = 0, s_idx;
+
+	s_idx = cb->args[0];
+
+	rcu_read_lock();
+
+	cb->seq = net->dev_base_seq;
+
+	for_each_netdev_rcu(net, dev) {
+		if (dev->priv_flags & IFF_EBRIDGE) {
+			struct br_port_msg *bpm;
+
+			if (idx < s_idx)
+				goto skip;
+
+			nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
+					cb->nlh->nlmsg_seq, RTM_GETMRP,
+					sizeof(*bpm), NLM_F_MULTI);
+			if (!nlh)
+				break;
+
+			bpm = nlmsg_data(nlh);
+			memset(bpm, 0, sizeof(*bpm));
+			bpm->ifindex = dev->ifindex;
+			if (br_mrp_fill_entry(skb, cb, dev) < 0)
+				goto out;
+
+			cb->args[1] = 0;
+			nlmsg_end(skb, nlh);
+skip:
+			idx++;
+		}
+	}
+
+out:
+	if (nlh)
+		nlmsg_end(skb, nlh);
+	rcu_read_unlock();
+	cb->args[0] = idx;
+	return skb->len;
+}
+
+static int br_mrp_add(struct sk_buff *skb, struct nlmsghdr *nlh,
+		      struct netlink_ext_ack *extack)
+{
+	struct net_bridge_port *p_port, *s_port;
+	struct net *net = sock_net(skb->sk);
+	enum br_mrp_ring_role_type role;
+	struct br_mrp_config conf;
+	struct net_device *dev;
+	struct net_bridge *br;
+	struct br_mrp *mrp;
+	u32 ring_nr;
+	int err;
+
+	err = br_mrp_parse(skb, nlh, &dev, &conf);
+	if (err < 0)
+		return err;
+
+	br = netdev_priv(dev);
+
+	/* Get priority and secondary ports */
+	dev = __dev_get_by_index(net, conf.p_ifindex);
+	if (!dev)
+		return -ENODEV;
+
+	p_port = br_port_get_rtnl(dev);
+	if (!p_port || p_port->br != br)
+		return -EINVAL;
+
+	dev = __dev_get_by_index(net, conf.s_ifindex);
+	if (!dev)
+		return -ENODEV;
+
+	s_port = br_port_get_rtnl(dev);
+	if (!s_port || s_port->br != br)
+		return -EINVAL;
+
+	/* Get role */
+	role = conf.ring_role;
+
+	/* Get ring number */
+	ring_nr = conf.ring_nr;
+
+	/* It is not possible to have MRP instances with the same ID */
+	mrp = br_mrp_find(br, ring_nr);
+	if (mrp)
+		return -EINVAL;
+
+	/* Create the mrp instance */
+	err = br_mrp_create(br, ring_nr);
+	if (err < 0)
+		return err;
+
+	mrp = br_mrp_find(br, ring_nr);
+
+	mutex_lock(&mrp->lock);
+
+	/* Initialize the ports */
+	err = br_mrp_port_init(p_port, mrp, BR_MRP_PORT_ROLE_PRIMARY);
+	if (err < 0) {
+		mutex_unlock(&mrp->lock);
+		goto delete_mrp;
+	}
+
+	err = br_mrp_port_init(s_port, mrp, BR_MRP_PORT_ROLE_SECONDARY);
+	if (err < 0) {
+		mutex_unlock(&mrp->lock);
+		goto delete_port;
+	}
+
+	if (role == BR_MRP_RING_ROLE_MRM)
+		br_mrp_set_mrm_role(mrp);
+	if (role == BR_MRP_RING_ROLE_MRC)
+		br_mrp_set_mrc_role(mrp);
+
+	mutex_unlock(&mrp->lock);
+
+	return 0;
+
+delete_port:
+	br_mrp_port_uninit(p_port);
+
+delete_mrp:
+	br_mrp_destroy(br, ring_nr);
+	return err;
+}
+
+static int br_mrp_del(struct sk_buff *skb, struct nlmsghdr *nlh,
+		      struct netlink_ext_ack *extack)
+{
+	struct br_mrp_config conf;
+	struct net_device *dev;
+	struct net_bridge *br;
+	struct br_mrp *mrp;
+	u32 ring_nr;
+	int err;
+
+	err = br_mrp_parse(skb, nlh, &dev, &conf);
+	if (err < 0)
+		return err;
+
+	br = netdev_priv(dev);
+
+	/* Get ring number */
+	ring_nr = conf.ring_nr;
+
+	mrp = br_mrp_find(br, ring_nr);
+	if (!mrp) {
+		pr_info("PF_BRIDGE: %s with invalid ring_nr\n", __func__);
+		return -EINVAL;
+	}
+
+	br_mrp_port_uninit(mrp->p_port);
+	br_mrp_port_uninit(mrp->s_port);
+
+	br_mrp_destroy(br, ring_nr);
+
+	return 0;
+}
+
+void br_mrp_netlink_init(void)
+{
+	rtnl_register_module(THIS_MODULE, PF_BRIDGE, RTM_GETMRP, NULL,
+			     br_mrp_dump, 0);
+	rtnl_register_module(THIS_MODULE, PF_BRIDGE, RTM_NEWMRP, br_mrp_add,
+			     NULL, 0);
+	rtnl_register_module(THIS_MODULE, PF_BRIDGE, RTM_DELMRP, br_mrp_del,
+			     NULL, 0);
+}
+
+void br_mrp_netlink_uninit(void)
+{
+	rtnl_unregister(PF_BRIDGE, RTM_GETMRP);
+	rtnl_unregister(PF_BRIDGE, RTM_NEWMRP);
+	rtnl_unregister(PF_BRIDGE, RTM_DELMRP);
+}
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index 60136575aea4..6d8f84ed8b0d 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -1664,6 +1664,9 @@ int __init br_netlink_init(void)
 	int err;
 
 	br_mdb_init();
+#ifdef CONFIG_BRIDGE_MRP
+	br_mrp_netlink_init();
+#endif
 	rtnl_af_register(&br_af_ops);
 
 	err = rtnl_link_register(&br_link_ops);
@@ -1674,12 +1677,18 @@ int __init br_netlink_init(void)
 
 out_af:
 	rtnl_af_unregister(&br_af_ops);
+#ifdef CONFIG_BRIDGE_MRP
+	br_mrp_netlink_uninit();
+#endif
 	br_mdb_uninit();
 	return err;
 }
 
 void br_netlink_fini(void)
 {
+#ifdef CONFIG_BRIDGE_MRP
+	br_mrp_netlink_uninit();
+#endif
 	br_mdb_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 0c008b3d24cc..9a060c3c7713 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -1169,6 +1169,8 @@ unsigned long br_timer_value(const struct timer_list *timer);
 
 #if IS_ENABLED(CONFIG_BRIDGE_MRP)
 /* br_mrp.c */
+void br_mrp_netlink_init(void);
+void br_mrp_netlink_uninit(void);
 void br_mrp_uninit(struct net_bridge *br);
 void br_mrp_port_uninit(struct net_bridge_port *p);
 void br_mrp_port_link_change(struct net_bridge_port *br, bool up);
diff --git a/net/bridge/br_private_mrp.h b/net/bridge/br_private_mrp.h
index 00ee20582ac9..13fd2330ccfc 100644
--- a/net/bridge/br_private_mrp.h
+++ b/net/bridge/br_private_mrp.h
@@ -174,6 +174,15 @@ struct br_mrp {
 	u16				react_on_link_change;
 };
 
+/* Represents the configuration of the MRP instance */
+struct br_mrp_config {
+	u32 p_ifindex;
+	u32 s_ifindex;
+	u32 ring_role;
+	u32 ring_nr;
+	u32 ring_state;
+};
+
 /* br_mrp.c */
 void br_mrp_ring_test_req(struct br_mrp *mrp, u32 interval);
 void br_mrp_ring_topo_req(struct br_mrp *mrp, u32 interval);
diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index c97fdae8f71b..7c110fdb9e1e 100644
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c
@@ -85,6 +85,9 @@ static const struct nlmsg_perm nlmsg_route_perms[] =
 	{ RTM_GETNEXTHOP,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
 	{ RTM_NEWLINKPROP,	NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
 	{ RTM_DELLINKPROP,	NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_NEWMRP,		NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_DELMRP,		NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
+	{ RTM_GETMRP,		NETLINK_ROUTE_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
@@ -168,7 +171,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
 		 * structures at the top of this file with the new mappings
 		 * before updating the BUILD_BUG_ON() macro!
 		 */
-		BUILD_BUG_ON(RTM_MAX != (RTM_NEWLINKPROP + 3));
+		BUILD_BUG_ON(RTM_MAX != (RTM_DELMRP + 3));
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
 				 sizeof(nlmsg_route_perms));
 		break;
-- 
2.17.1