[PATCH v3 net-next 2/6] rtnetlink: Add new RTM_GETEECSTATE message to get SyncE status

[Maciej Machnikowski <maciej.machnikowski@intel.com>]

This patch series introduces basic interface for reading the Ethernet
Equipment Clock (EEC) state on a SyncE capable device. This state gives
information about the state of EEC. This interface is required to
implement Synchronization Status Messaging on upper layers.

Initial implementation returns SyncE EEC state in the IFLA_EEC_STATE
attribute. The optional index of input that's used as a source can be
returned in the IFLA_EEC_SRC_IDX attribute.

SyncE EEC state read needs to be implemented as a ndo_get_eec_state
function. The index will be read by calling the ndo_get_eec_src.

Signed-off-by: Maciej Machnikowski <maciej.machnikowski@intel.com>
---
 include/linux/netdevice.h      | 13 ++++++
 include/uapi/linux/if_link.h   | 27 ++++++++++++
 include/uapi/linux/rtnetlink.h |  3 ++
 net/core/rtnetlink.c           | 79 ++++++++++++++++++++++++++++++++++
 security/selinux/nlmsgtab.c    |  3 +-
 5 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3ec42495a43a..ef2b381dae0c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1344,6 +1344,13 @@ struct netdev_net_notifier {
  *	The caller must be under RCU read context.
  * int (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx, struct net_device_path *path);
  *     Get the forwarding path to reach the real device from the HW destination address
+ * int (*ndo_get_eec_state)(struct net_device *dev, enum if_eec_state *state,
+ *			    u32 *src_idx, struct netlink_ext_ack *extack);
+ *	Get state of physical layer frequency synchronization (SyncE)
+ * int (*ndo_get_eec_src)(struct net_device *dev, u32 *src,
+ *			  struct netlink_ext_ack *extack);
+ *	Get the index of the source signal that's currently used as EEC's
+ *	reference
  */
 struct net_device_ops {
 	int			(*ndo_init)(struct net_device *dev);
@@ -1563,6 +1570,12 @@ struct net_device_ops {
 	struct net_device *	(*ndo_get_peer_dev)(struct net_device *dev);
 	int                     (*ndo_fill_forward_path)(struct net_device_path_ctx *ctx,
                                                          struct net_device_path *path);
+	int			(*ndo_get_eec_state)(struct net_device *dev,
+						     enum if_eec_state *state,
+						     struct netlink_ext_ack *extack);
+	int			(*ndo_get_eec_src)(struct net_device *dev,
+						   u32 *src,
+						   struct netlink_ext_ack *extack);
 };
 
 /**
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index eebd3894fe89..3628a55fdd10 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1273,4 +1273,31 @@ enum {
 
 #define IFLA_MCTP_MAX (__IFLA_MCTP_MAX - 1)
 
+/* SyncE section */
+
+enum if_eec_state {
+	IF_EEC_STATE_INVALID = 0,	/* state is not valid */
+	IF_EEC_STATE_FREERUN,		/* clock is free-running */
+	IF_EEC_STATE_LOCKED,		/* clock is locked to the reference,
+					 * but the holdover memory is not valid
+					 */
+	IF_EEC_STATE_LOCKED_HO_ACQ,	/* clock is locked to the reference
+					 * and holdover memory is valid
+					 */
+	IF_EEC_STATE_HOLDOVER,		/* clock is in holdover mode */
+};
+
+struct if_eec_state_msg {
+	__u32 ifindex;
+};
+
+enum {
+	IFLA_EEC_UNSPEC,
+	IFLA_EEC_STATE,
+	IFLA_EEC_SRC_IDX,
+	__IFLA_EEC_MAX,
+};
+
+#define IFLA_EEC_MAX (__IFLA_EEC_MAX - 1)
+
 #endif /* _UAPI_LINUX_IF_LINK_H */
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 5888492a5257..1d8662afd6bd 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -185,6 +185,9 @@ enum {
 	RTM_GETNEXTHOPBUCKET,
 #define RTM_GETNEXTHOPBUCKET	RTM_GETNEXTHOPBUCKET
 
+	RTM_GETEECSTATE = 124,
+#define RTM_GETEECSTATE	RTM_GETEECSTATE
+
 	__RTM_MAX,
 #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
 };
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2af8aeeadadf..03bc773d0e69 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -5467,6 +5467,83 @@ static int rtnl_stats_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+static int rtnl_fill_eec_state(struct sk_buff *skb, struct net_device *dev,
+			       u32 portid, u32 seq, struct netlink_callback *cb,
+			       int flags, struct netlink_ext_ack *extack)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct if_eec_state_msg *state_msg;
+	enum if_eec_state state;
+	struct nlmsghdr *nlh;
+	u32 src_idx;
+	int err;
+
+	ASSERT_RTNL();
+
+	if (!ops->ndo_get_eec_state)
+		return -EOPNOTSUPP;
+
+	err = ops->ndo_get_eec_state(dev, &state, extack);
+	if (err)
+		return err;
+
+	nlh = nlmsg_put(skb, portid, seq, RTM_GETEECSTATE, sizeof(*state_msg),
+			flags);
+	if (!nlh)
+		return -EMSGSIZE;
+
+	state_msg = nlmsg_data(nlh);
+	state_msg->ifindex = dev->ifindex;
+
+	if (nla_put_u32(skb, IFLA_EEC_STATE, state))
+		return -EMSGSIZE;
+
+	if (!ops->ndo_get_eec_src)
+		goto end_msg;
+
+	err = ops->ndo_get_eec_src(dev, &src_idx, extack);
+	if (err)
+		return err;
+
+	if (nla_put_u32(skb, IFLA_EEC_SRC_IDX, src_idx))
+		return -EMSGSIZE;
+
+end_msg:
+	nlmsg_end(skb, nlh);
+	return 0;
+}
+
+static int rtnl_eec_state_get(struct sk_buff *skb, struct nlmsghdr *nlh,
+			      struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct if_eec_state_msg *state;
+	struct net_device *dev;
+	struct sk_buff *nskb;
+	int err;
+
+	state = nlmsg_data(nlh);
+	dev = __dev_get_by_index(net, state->ifindex);
+	if (!dev) {
+		NL_SET_ERR_MSG(extack, "unknown ifindex");
+		return -ENODEV;
+	}
+
+	nskb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!nskb)
+		return -ENOBUFS;
+
+	err = rtnl_fill_eec_state(nskb, dev, NETLINK_CB(skb).portid,
+				  nlh->nlmsg_seq, NULL, nlh->nlmsg_flags,
+				  extack);
+	if (err < 0)
+		kfree_skb(nskb);
+	else
+		err = rtnl_unicast(nskb, net, NETLINK_CB(skb).portid);
+
+	return err;
+}
+
 /* Process one rtnetlink message. */
 
 static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -5692,4 +5769,6 @@ void __init rtnetlink_init(void)
 
 	rtnl_register(PF_UNSPEC, RTM_GETSTATS, rtnl_stats_get, rtnl_stats_dump,
 		      0);
+
+	rtnl_register(PF_UNSPEC, RTM_GETEECSTATE, rtnl_eec_state_get, NULL, 0);
 }
diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index 94ea2a8b2bb7..2c66e722ea9c 100644
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c
@@ -91,6 +91,7 @@ static const struct nlmsg_perm nlmsg_route_perms[] =
 	{ RTM_NEWNEXTHOPBUCKET,	NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
 	{ RTM_DELNEXTHOPBUCKET,	NETLINK_ROUTE_SOCKET__NLMSG_WRITE },
 	{ RTM_GETNEXTHOPBUCKET,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
+	{ RTM_GETEECSTATE,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
@@ -176,7 +177,7 @@ 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_NEWNEXTHOPBUCKET + 3));
+		BUILD_BUG_ON(RTM_MAX != (RTM_GETEECSTATE + 3));
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
 				 sizeof(nlmsg_route_perms));
 		break;
-- 
2.26.3