tipc: get monitor threshold for the cluster

In this commit, we add support to fetch the configured
cluster monitoring threshold.

Reviewed-by: Jon Maloy <[e-mail]>
Signed-off-by: Parthasarathy Bhuvaragan <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/tipc_netlink.h

···
 	TIPC_NL_NET_SET,
 	TIPC_NL_NAME_TABLE_GET,
 	TIPC_NL_MON_SET,
+	TIPC_NL_MON_GET,
 
 	__TIPC_NL_CMD_MAX,
 	TIPC_NL_CMD_MAX = __TIPC_NL_CMD_MAX - 1

net/tipc/monitor.c

···
 
 	return 0;
 }
+
+int tipc_nl_monitor_get_threshold(struct net *net)
+{
+	struct tipc_net *tn = tipc_net(net);
+
+	return tn->mon_threshold;
+}

net/tipc/monitor.h

···
 void tipc_mon_remove_peer(struct net *net, u32 addr, int bearer_id);
 
 int tipc_nl_monitor_set_threshold(struct net *net, u32 cluster_size);
+int tipc_nl_monitor_get_threshold(struct net *net);
+
 extern const int tipc_max_domain_size;
 #endif

net/tipc/netlink.c

···
 		.doit	= tipc_nl_node_set_monitor,
 		.policy = tipc_nl_policy,
 	},
+	{
+		.cmd	= TIPC_NL_MON_GET,
+		.doit	= tipc_nl_node_get_monitor,
+		.policy = tipc_nl_policy,
+	},
 };
 
 int tipc_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr ***attr)

net/tipc/node.c

···
 
 	return 0;
 }
+
+static int __tipc_nl_add_monitor_prop(struct net *net, struct tipc_nl_msg *msg)
+{
+	struct nlattr *attrs;
+	void *hdr;
+	u32 val;
+
+	hdr = genlmsg_put(msg->skb, msg->portid, msg->seq, &tipc_genl_family,
+			  0, TIPC_NL_MON_GET);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	attrs = nla_nest_start(msg->skb, TIPC_NLA_MON);
+	if (!attrs)
+		goto msg_full;
+
+	val = tipc_nl_monitor_get_threshold(net);
+
+	if (nla_put_u32(msg->skb, TIPC_NLA_MON_ACTIVATION_THRESHOLD, val))
+		goto attr_msg_full;
+
+	nla_nest_end(msg->skb, attrs);
+	genlmsg_end(msg->skb, hdr);
+
+	return 0;
+
+attr_msg_full:
+	nla_nest_cancel(msg->skb, attrs);
+msg_full:
+	genlmsg_cancel(msg->skb, hdr);
+
+	return -EMSGSIZE;
+}
+
+int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tipc_nl_msg msg;
+	int err;
+
+	msg.skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	msg.portid = info->snd_portid;
+	msg.seq = info->snd_seq;
+
+	err = __tipc_nl_add_monitor_prop(net, &msg);
+	if (err) {
+		nlmsg_free(msg.skb);
+		return err;
+	}
+
+	return genlmsg_reply(msg.skb, info);
+}

net/tipc/node.h

···
 int tipc_nl_node_set_link(struct sk_buff *skb, struct genl_info *info);
 
 int tipc_nl_node_set_monitor(struct sk_buff *skb, struct genl_info *info);
+int tipc_nl_node_get_monitor(struct sk_buff *skb, struct genl_info *info);
 #endif