[RFC v2 net-next 1/2] rtnetlink: Add new RTM_GETSYNCESTATE message to get SyncE status

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

This patch adds the new RTM_GETSYNCESTATE message to query the status
of SyncE syntonization on the device.

Initial implementation returns:
 - SyncE DPLL state
 - Source of signal driving SyncE DPLL (SyncE, GNSS, PTP or External)
 - Current index of Pin driving the DPLL

SyncE state read needs to be implemented as ndo_get_synce_state function.

This patch is SyncE-oriented. Future implementation can add additional
functionality for reading different DPLL states using the same structure.

Signed-off-by: Maciej Machnikowski <maciej.machnikowski@intel.com>
---
 include/linux/netdevice.h      |  6 +++
 include/uapi/linux/if_link.h   | 43 +++++++++++++++++++
 include/uapi/linux/rtnetlink.h | 11 +++--
 net/core/rtnetlink.c           | 77 ++++++++++++++++++++++++++++++++++
 security/selinux/nlmsgtab.c    |  3 +-
 5 files changed, 135 insertions(+), 5 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6fd3a4d42668..a091a35706a7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1344,6 +1344,8 @@ 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_synce_state)(struct net_device *dev, struct if_synce_state_msg *state)
+ *	Get state of physical layer frequency syntonization (SyncE)
  */
 struct net_device_ops {
 	int			(*ndo_init)(struct net_device *dev);
@@ -1563,6 +1565,10 @@ 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_synce_state)(struct net_device *dev,
+						       enum if_synce_state *state,
+						       enum if_synce_src *src,
+						       u8 *pin_idx);
 };
 
 /**
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index eebd3894fe89..1fcb9c71dc7c 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1273,4 +1273,47 @@ enum {
 
 #define IFLA_MCTP_MAX (__IFLA_MCTP_MAX - 1)
 
+/* SyncE section */
+
+enum if_synce_state {
+	IF_SYNCE_STATE_INVALID = 0,
+	IF_SYNCE_STATE_FREERUN,
+	IF_SYNCE_STATE_LOCKACQ,
+	IF_SYNCE_STATE_LOCKREC,
+	IF_SYNCE_STATE_LOCKED,
+	IF_SYNCE_STATE_HOLDOVER,
+	IF_SYNCE_STATE_OPEN_LOOP,
+	__IF_SYNCE_STATE_MAX,
+};
+
+#define IF_SYNCE_STATE_MAX (__IF_SYNCE_STATE_MAX - 1)
+
+enum if_synce_src {
+	IF_SYNCE_SRC_INVALID = 0,
+	IF_SYNCE_SRC_UNKNOWN,
+	IF_SYNCE_SRC_SYNCE,
+	IF_SYNCE_SRC_GNSS,
+	IF_SYNCE_SRC_PTP,
+	IF_SYNCE_SRC_EXT,
+	__IF_SYNCE_SRC_MAX,
+};
+
+#define IF_SYNCE_PIN_UNKNOWN	0xFF
+
+struct if_synce_state_msg {
+	__u32 ifindex;
+	__u8 state;
+	__u8 src;
+	__u8 pin;
+	__u8 pad;
+};
+
+enum {
+	IFLA_SYNCE_UNSPEC,
+	IFLA_SYNCE_STATE,
+	__IFLA_SYNCE_MAX,
+};
+
+#define IFLA_SYNCE_MAX (__IFLA_SYNCE_MAX - 1)
+
 #endif /* _UAPI_LINUX_IF_LINK_H */
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 5888492a5257..cd68045c475b 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_GETSYNCESTATE = 120,
+#define RTM_GETSYNCESTATE	RTM_GETSYNCESTATE
+
 	__RTM_MAX,
 #define RTM_MAX		(((__RTM_MAX + 3) & ~3) - 1)
 };
@@ -193,7 +196,7 @@ enum {
 #define RTM_NR_FAMILIES	(RTM_NR_MSGTYPES >> 2)
 #define RTM_FAM(cmd)	(((cmd) - RTM_BASE) >> 2)
 
-/* 
+/*
    Generic structure for encapsulation of optional route information.
    It is reminiscent of sockaddr, but with sa_family replaced
    with attribute type.
@@ -233,7 +236,7 @@ struct rtmsg {
 
 	unsigned char		rtm_table;	/* Routing table id */
 	unsigned char		rtm_protocol;	/* Routing protocol; see below	*/
-	unsigned char		rtm_scope;	/* See below */	
+	unsigned char		rtm_scope;	/* See below */
 	unsigned char		rtm_type;	/* See below	*/
 
 	unsigned		rtm_flags;
@@ -555,7 +558,7 @@ struct ifinfomsg {
 };
 
 /********************************************************************
- *		prefix information 
+ *		prefix information
  ****/
 
 struct prefixmsg {
@@ -569,7 +572,7 @@ struct prefixmsg {
 	unsigned char	prefix_pad3;
 };
 
-enum 
+enum
 {
 	PREFIX_UNSPEC,
 	PREFIX_ADDRESS,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 972c8cb303a5..8c9638421049 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -5468,6 +5468,81 @@ static int rtnl_stats_dump(struct sk_buff *skb, struct netlink_callback *cb)
 	return skb->len;
 }
 
+static int rtnl_fill_synce_state(struct sk_buff *msg, struct net_device *dev,
+				 u32 portid, u32 seq,
+				 struct netlink_callback *cb,
+				 int flags)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct if_synce_state_msg *state;
+	struct nlmsghdr *nlh;
+
+	ASSERT_RTNL();
+
+	nlh = nlmsg_put(msg, portid, seq, RTM_GETSYNCESTATE,
+			sizeof(*state), flags);
+	if (!nlh)
+		return -EMSGSIZE;
+
+	state = nlmsg_data(nlh);
+
+	if (ops->ndo_get_synce_state) {
+		enum if_synce_state sync_state;
+		enum if_synce_src src;
+		int err;
+		u8 pin;
+
+		err = ops->ndo_get_synce_state(dev, &sync_state, &src, &pin);
+		if (err)
+			return err;
+
+		memset(state, 0, sizeof(*state));
+
+		state->ifindex = dev->ifindex;
+		state->state = (u8)sync_state;
+		state->pin = pin;
+		state->src = (u8)src;
+
+		return 0;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static int rtnl_synce_state_get(struct sk_buff *skb, struct nlmsghdr *nlh,
+				struct netlink_ext_ack *extack)
+{
+	struct net *net = sock_net(skb->sk);
+	struct if_synce_state_msg *state;
+	struct net_device *dev = NULL;
+	struct sk_buff *nskb;
+	u32 filter_mask;
+	int err;
+
+	state = nlmsg_data(nlh);
+	if (state->ifindex > 0)
+		dev = __dev_get_by_index(net, state->ifindex);
+	else
+		return -EINVAL;
+
+	nskb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!nskb)
+		return -ENOBUFS;
+
+	if (!dev)
+		return -ENODEV;
+
+	err = rtnl_fill_synce_state(nskb, dev,
+				    NETLINK_CB(skb).portid, nlh->nlmsg_seq,
+				    NULL, filter_mask);
+	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,
@@ -5693,4 +5768,6 @@ void __init rtnetlink_init(void)
 
 	rtnl_register(PF_UNSPEC, RTM_GETSTATS, rtnl_stats_get, rtnl_stats_dump,
 		      0);
+
+	rtnl_register(PF_UNSPEC, RTM_GETSYNCESTATE, rtnl_synce_state_get, NULL, 0);
 }
diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index d59276f48d4f..b4bea120f2af 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_GETSYNCESTATE,	NETLINK_ROUTE_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_tcpdiag_perms[] =
@@ -174,7 +175,7 @@ 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_GETSYNCESTATE + 3));
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_route_perms,
 				 sizeof(nlmsg_route_perms));
 		break;
-- 
2.26.3