1 files changed, 1285 insertions, 60 deletions

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 4ea4347f5062..536e032d95c8 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -26,6 +26,7 @@
 #include <linux/bitops.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <net/drop_monitor.h>
 #include <net/genetlink.h>
 #include <net/netevent.h>
 
@@ -43,13 +44,44 @@
  * netlink alerts
  */
 static int trace_state = TRACE_OFF;
-static DEFINE_MUTEX(trace_state_mutex);
+static bool monitor_hw;
+
+/* net_dm_mutex
+ *
+ * An overall lock guarding every operation coming from userspace.
+ * It also guards the global 'hw_stats_list' list.
+ */
+static DEFINE_MUTEX(net_dm_mutex);
+
+struct net_dm_stats {
+	u64 dropped;
+	struct u64_stats_sync syncp;
+};
+
+#define NET_DM_MAX_HW_TRAP_NAME_LEN 40
+
+struct net_dm_hw_entry {
+	char trap_name[NET_DM_MAX_HW_TRAP_NAME_LEN];
+	u32 count;
+};
+
+struct net_dm_hw_entries {
+	u32 num_entries;
+	struct net_dm_hw_entry entries[0];
+};
 
 struct per_cpu_dm_data {
-	spinlock_t		lock;
-	struct sk_buff		*skb;
+	spinlock_t		lock;	/* Protects 'skb', 'hw_entries' and
+					 * 'send_timer'
+					 */
+	union {
+		struct sk_buff			*skb;
+		struct net_dm_hw_entries	*hw_entries;
+	};
+	struct sk_buff_head	drop_queue;
 	struct work_struct	dm_alert_work;
 	struct timer_list	send_timer;
+	struct net_dm_stats	stats;
 };
 
 struct dm_hw_stat_delta {
@@ -63,12 +95,37 @@ struct dm_hw_stat_delta {
 static struct genl_family net_drop_monitor_family;
 
 static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_cpu_data);
+static DEFINE_PER_CPU(struct per_cpu_dm_data, dm_hw_cpu_data);
 
 static int dm_hit_limit = 64;
 static int dm_delay = 1;
 static unsigned long dm_hw_check_delta = 2*HZ;
 static LIST_HEAD(hw_stats_list);
 
+static enum net_dm_alert_mode net_dm_alert_mode = NET_DM_ALERT_MODE_SUMMARY;
+static u32 net_dm_trunc_len;
+static u32 net_dm_queue_len = 1000;
+
+struct net_dm_alert_ops {
+	void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
+				void *location);
+	void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
+				int work, int budget);
+	void (*work_item_func)(struct work_struct *work);
+	void (*hw_work_item_func)(struct work_struct *work);
+	void (*hw_probe)(struct sk_buff *skb,
+			 const struct net_dm_hw_metadata *hw_metadata);
+};
+
+struct net_dm_skb_cb {
+	union {
+		struct net_dm_hw_metadata *hw_metadata;
+		void *pc;
+	};
+};
+
+#define NET_DM_SKB_CB(__skb) ((struct net_dm_skb_cb *)&((__skb)->cb[0]))
+
 static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data)
 {
 	size_t al;
@@ -235,48 +292,844 @@ static void trace_napi_poll_hit(void *ignore, struct napi_struct *napi,
 	rcu_read_unlock();
 }
 
-static int set_all_monitor_traces(int state)
+static struct net_dm_hw_entries *
+net_dm_hw_reset_per_cpu_data(struct per_cpu_dm_data *hw_data)
 {
-	int rc = 0;
-	struct dm_hw_stat_delta *new_stat = NULL;
-	struct dm_hw_stat_delta *temp;
+	struct net_dm_hw_entries *hw_entries;
+	unsigned long flags;
+
+	hw_entries = kzalloc(struct_size(hw_entries, entries, dm_hit_limit),
+			     GFP_KERNEL);
+	if (!hw_entries) {
+		/* If the memory allocation failed, we try to perform another
+		 * allocation in 1/10 second. Otherwise, the probe function
+		 * will constantly bail out.
+		 */
+		mod_timer(&hw_data->send_timer, jiffies + HZ / 10);
+	}
 
-	mutex_lock(&trace_state_mutex);
+	spin_lock_irqsave(&hw_data->lock, flags);
+	swap(hw_data->hw_entries, hw_entries);
+	spin_unlock_irqrestore(&hw_data->lock, flags);
 
-	if (state == trace_state) {
-		rc = -EAGAIN;
-		goto out_unlock;
+	return hw_entries;
+}
+
+static int net_dm_hw_entry_put(struct sk_buff *msg,
+			       const struct net_dm_hw_entry *hw_entry)
+{
+	struct nlattr *attr;
+
+	attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRY);
+	if (!attr)
+		return -EMSGSIZE;
+
+	if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME, hw_entry->trap_name))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NET_DM_ATTR_HW_TRAP_COUNT, hw_entry->count))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, attr);
+	return -EMSGSIZE;
+}
+
+static int net_dm_hw_entries_put(struct sk_buff *msg,
+				 const struct net_dm_hw_entries *hw_entries)
+{
+	struct nlattr *attr;
+	int i;
+
+	attr = nla_nest_start(msg, NET_DM_ATTR_HW_ENTRIES);
+	if (!attr)
+		return -EMSGSIZE;
+
+	for (i = 0; i < hw_entries->num_entries; i++) {
+		int rc;
+
+		rc = net_dm_hw_entry_put(msg, &hw_entries->entries[i]);
+		if (rc)
+			goto nla_put_failure;
 	}
 
-	switch (state) {
-	case TRACE_ON:
-		if (!try_module_get(THIS_MODULE)) {
-			rc = -ENODEV;
-			break;
+	nla_nest_end(msg, attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, attr);
+	return -EMSGSIZE;
+}
+
+static int
+net_dm_hw_summary_report_fill(struct sk_buff *msg,
+			      const struct net_dm_hw_entries *hw_entries)
+{
+	struct net_dm_alert_msg anc_hdr = { 0 };
+	void *hdr;
+	int rc;
+
+	hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
+			  NET_DM_CMD_ALERT);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	/* We need to put the ancillary header in order not to break user
+	 * space.
+	 */
+	if (nla_put(msg, NLA_UNSPEC, sizeof(anc_hdr), &anc_hdr))
+		goto nla_put_failure;
+
+	rc = net_dm_hw_entries_put(msg, hw_entries);
+	if (rc)
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static void net_dm_hw_summary_work(struct work_struct *work)
+{
+	struct net_dm_hw_entries *hw_entries;
+	struct per_cpu_dm_data *hw_data;
+	struct sk_buff *msg;
+	int rc;
+
+	hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
+
+	hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
+	if (!hw_entries)
+		return;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		goto out;
+
+	rc = net_dm_hw_summary_report_fill(msg, hw_entries);
+	if (rc) {
+		nlmsg_free(msg);
+		goto out;
+	}
+
+	genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
+
+out:
+	kfree(hw_entries);
+}
+
+static void
+net_dm_hw_summary_probe(struct sk_buff *skb,
+			const struct net_dm_hw_metadata *hw_metadata)
+{
+	struct net_dm_hw_entries *hw_entries;
+	struct net_dm_hw_entry *hw_entry;
+	struct per_cpu_dm_data *hw_data;
+	unsigned long flags;
+	int i;
+
+	hw_data = this_cpu_ptr(&dm_hw_cpu_data);
+	spin_lock_irqsave(&hw_data->lock, flags);
+	hw_entries = hw_data->hw_entries;
+
+	if (!hw_entries)
+		goto out;
+
+	for (i = 0; i < hw_entries->num_entries; i++) {
+		hw_entry = &hw_entries->entries[i];
+		if (!strncmp(hw_entry->trap_name, hw_metadata->trap_name,
+			     NET_DM_MAX_HW_TRAP_NAME_LEN - 1)) {
+			hw_entry->count++;
+			goto out;
 		}
+	}
+	if (WARN_ON_ONCE(hw_entries->num_entries == dm_hit_limit))
+		goto out;
 
-		rc |= register_trace_kfree_skb(trace_kfree_skb_hit, NULL);
-		rc |= register_trace_napi_poll(trace_napi_poll_hit, NULL);
-		break;
+	hw_entry = &hw_entries->entries[hw_entries->num_entries];
+	strlcpy(hw_entry->trap_name, hw_metadata->trap_name,
+		NET_DM_MAX_HW_TRAP_NAME_LEN - 1);
+	hw_entry->count = 1;
+	hw_entries->num_entries++;
 
-	case TRACE_OFF:
-		rc |= unregister_trace_kfree_skb(trace_kfree_skb_hit, NULL);
-		rc |= unregister_trace_napi_poll(trace_napi_poll_hit, NULL);
+	if (!timer_pending(&hw_data->send_timer)) {
+		hw_data->send_timer.expires = jiffies + dm_delay * HZ;
+		add_timer(&hw_data->send_timer);
+	}
 
-		tracepoint_synchronize_unregister();
+out:
+	spin_unlock_irqrestore(&hw_data->lock, flags);
+}
 
-		/*
-		 * Clean the device list
+static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
+	.kfree_skb_probe	= trace_kfree_skb_hit,
+	.napi_poll_probe	= trace_napi_poll_hit,
+	.work_item_func		= send_dm_alert,
+	.hw_work_item_func	= net_dm_hw_summary_work,
+	.hw_probe		= net_dm_hw_summary_probe,
+};
+
+static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
+					      struct sk_buff *skb,
+					      void *location)
+{
+	ktime_t tstamp = ktime_get_real();
+	struct per_cpu_dm_data *data;
+	struct sk_buff *nskb;
+	unsigned long flags;
+
+	if (!skb_mac_header_was_set(skb))
+		return;
+
+	nskb = skb_clone(skb, GFP_ATOMIC);
+	if (!nskb)
+		return;
+
+	NET_DM_SKB_CB(nskb)->pc = location;
+	/* Override the timestamp because we care about the time when the
+	 * packet was dropped.
+	 */
+	nskb->tstamp = tstamp;
+
+	data = this_cpu_ptr(&dm_cpu_data);
+
+	spin_lock_irqsave(&data->drop_queue.lock, flags);
+	if (skb_queue_len(&data->drop_queue) < net_dm_queue_len)
+		__skb_queue_tail(&data->drop_queue, nskb);
+	else
+		goto unlock_free;
+	spin_unlock_irqrestore(&data->drop_queue.lock, flags);
+
+	schedule_work(&data->dm_alert_work);
+
+	return;
+
+unlock_free:
+	spin_unlock_irqrestore(&data->drop_queue.lock, flags);
+	u64_stats_update_begin(&data->stats.syncp);
+	data->stats.dropped++;
+	u64_stats_update_end(&data->stats.syncp);
+	consume_skb(nskb);
+}
+
+static void net_dm_packet_trace_napi_poll_hit(void *ignore,
+					      struct napi_struct *napi,
+					      int work, int budget)
+{
+}
+
+static size_t net_dm_in_port_size(void)
+{
+	       /* NET_DM_ATTR_IN_PORT nest */
+	return nla_total_size(0) +
+	       /* NET_DM_ATTR_PORT_NETDEV_IFINDEX */
+	       nla_total_size(sizeof(u32)) +
+	       /* NET_DM_ATTR_PORT_NETDEV_NAME */
+	       nla_total_size(IFNAMSIZ + 1);
+}
+
+#define NET_DM_MAX_SYMBOL_LEN 40
+
+static size_t net_dm_packet_report_size(size_t payload_len)
+{
+	size_t size;
+
+	size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
+
+	return NLMSG_ALIGN(size) +
+	       /* NET_DM_ATTR_ORIGIN */
+	       nla_total_size(sizeof(u16)) +
+	       /* NET_DM_ATTR_PC */
+	       nla_total_size(sizeof(u64)) +
+	       /* NET_DM_ATTR_SYMBOL */
+	       nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) +
+	       /* NET_DM_ATTR_IN_PORT */
+	       net_dm_in_port_size() +
+	       /* NET_DM_ATTR_TIMESTAMP */
+	       nla_total_size(sizeof(u64)) +
+	       /* NET_DM_ATTR_ORIG_LEN */
+	       nla_total_size(sizeof(u32)) +
+	       /* NET_DM_ATTR_PROTO */
+	       nla_total_size(sizeof(u16)) +
+	       /* NET_DM_ATTR_PAYLOAD */
+	       nla_total_size(payload_len);
+}
+
+static int net_dm_packet_report_in_port_put(struct sk_buff *msg, int ifindex,
+					    const char *name)
+{
+	struct nlattr *attr;
+
+	attr = nla_nest_start(msg, NET_DM_ATTR_IN_PORT);
+	if (!attr)
+		return -EMSGSIZE;
+
+	if (ifindex &&
+	    nla_put_u32(msg, NET_DM_ATTR_PORT_NETDEV_IFINDEX, ifindex))
+		goto nla_put_failure;
+
+	if (name && nla_put_string(msg, NET_DM_ATTR_PORT_NETDEV_NAME, name))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, attr);
+	return -EMSGSIZE;
+}
+
+static int net_dm_packet_report_fill(struct sk_buff *msg, struct sk_buff *skb,
+				     size_t payload_len)
+{
+	u64 pc = (u64)(uintptr_t) NET_DM_SKB_CB(skb)->pc;
+	char buf[NET_DM_MAX_SYMBOL_LEN];
+	struct nlattr *attr;
+	void *hdr;
+	int rc;
+
+	hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
+			  NET_DM_CMD_PACKET_ALERT);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_SW))
+		goto nla_put_failure;
+
+	if (nla_put_u64_64bit(msg, NET_DM_ATTR_PC, pc, NET_DM_ATTR_PAD))
+		goto nla_put_failure;
+
+	snprintf(buf, sizeof(buf), "%pS", NET_DM_SKB_CB(skb)->pc);
+	if (nla_put_string(msg, NET_DM_ATTR_SYMBOL, buf))
+		goto nla_put_failure;
+
+	rc = net_dm_packet_report_in_port_put(msg, skb->skb_iif, NULL);
+	if (rc)
+		goto nla_put_failure;
+
+	if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
+			      ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
+		goto nla_put_failure;
+
+	if (!payload_len)
+		goto out;
+
+	if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
+		goto nla_put_failure;
+
+	attr = skb_put(msg, nla_total_size(payload_len));
+	attr->nla_type = NET_DM_ATTR_PAYLOAD;
+	attr->nla_len = nla_attr_size(payload_len);
+	if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
+		goto nla_put_failure;
+
+out:
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+#define NET_DM_MAX_PACKET_SIZE (0xffff - NLA_HDRLEN - NLA_ALIGNTO)
+
+static void net_dm_packet_report(struct sk_buff *skb)
+{
+	struct sk_buff *msg;
+	size_t payload_len;
+	int rc;
+
+	/* Make sure we start copying the packet from the MAC header */
+	if (skb->data > skb_mac_header(skb))
+		skb_push(skb, skb->data - skb_mac_header(skb));
+	else
+		skb_pull(skb, skb_mac_header(skb) - skb->data);
+
+	/* Ensure packet fits inside a single netlink attribute */
+	payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
+	if (net_dm_trunc_len)
+		payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
+
+	msg = nlmsg_new(net_dm_packet_report_size(payload_len), GFP_KERNEL);
+	if (!msg)
+		goto out;
+
+	rc = net_dm_packet_report_fill(msg, skb, payload_len);
+	if (rc) {
+		nlmsg_free(msg);
+		goto out;
+	}
+
+	genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
+
+out:
+	consume_skb(skb);
+}
+
+static void net_dm_packet_work(struct work_struct *work)
+{
+	struct per_cpu_dm_data *data;
+	struct sk_buff_head list;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
+
+	__skb_queue_head_init(&list);
+
+	spin_lock_irqsave(&data->drop_queue.lock, flags);
+	skb_queue_splice_tail_init(&data->drop_queue, &list);
+	spin_unlock_irqrestore(&data->drop_queue.lock, flags);
+
+	while ((skb = __skb_dequeue(&list)))
+		net_dm_packet_report(skb);
+}
+
+static size_t
+net_dm_hw_packet_report_size(size_t payload_len,
+			     const struct net_dm_hw_metadata *hw_metadata)
+{
+	size_t size;
+
+	size = nlmsg_msg_size(GENL_HDRLEN + net_drop_monitor_family.hdrsize);
+
+	return NLMSG_ALIGN(size) +
+	       /* NET_DM_ATTR_ORIGIN */
+	       nla_total_size(sizeof(u16)) +
+	       /* NET_DM_ATTR_HW_TRAP_GROUP_NAME */
+	       nla_total_size(strlen(hw_metadata->trap_group_name) + 1) +
+	       /* NET_DM_ATTR_HW_TRAP_NAME */
+	       nla_total_size(strlen(hw_metadata->trap_name) + 1) +
+	       /* NET_DM_ATTR_IN_PORT */
+	       net_dm_in_port_size() +
+	       /* NET_DM_ATTR_TIMESTAMP */
+	       nla_total_size(sizeof(u64)) +
+	       /* NET_DM_ATTR_ORIG_LEN */
+	       nla_total_size(sizeof(u32)) +
+	       /* NET_DM_ATTR_PROTO */
+	       nla_total_size(sizeof(u16)) +
+	       /* NET_DM_ATTR_PAYLOAD */
+	       nla_total_size(payload_len);
+}
+
+static int net_dm_hw_packet_report_fill(struct sk_buff *msg,
+					struct sk_buff *skb, size_t payload_len)
+{
+	struct net_dm_hw_metadata *hw_metadata;
+	struct nlattr *attr;
+	void *hdr;
+
+	hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
+
+	hdr = genlmsg_put(msg, 0, 0, &net_drop_monitor_family, 0,
+			  NET_DM_CMD_PACKET_ALERT);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u16(msg, NET_DM_ATTR_ORIGIN, NET_DM_ORIGIN_HW))
+		goto nla_put_failure;
+
+	if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_GROUP_NAME,
+			   hw_metadata->trap_group_name))
+		goto nla_put_failure;
+
+	if (nla_put_string(msg, NET_DM_ATTR_HW_TRAP_NAME,
+			   hw_metadata->trap_name))
+		goto nla_put_failure;
+
+	if (hw_metadata->input_dev) {
+		struct net_device *dev = hw_metadata->input_dev;
+		int rc;
+
+		rc = net_dm_packet_report_in_port_put(msg, dev->ifindex,
+						      dev->name);
+		if (rc)
+			goto nla_put_failure;
+	}
+
+	if (nla_put_u64_64bit(msg, NET_DM_ATTR_TIMESTAMP,
+			      ktime_to_ns(skb->tstamp), NET_DM_ATTR_PAD))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NET_DM_ATTR_ORIG_LEN, skb->len))
+		goto nla_put_failure;
+
+	if (!payload_len)
+		goto out;
+
+	if (nla_put_u16(msg, NET_DM_ATTR_PROTO, be16_to_cpu(skb->protocol)))
+		goto nla_put_failure;
+
+	attr = skb_put(msg, nla_total_size(payload_len));
+	attr->nla_type = NET_DM_ATTR_PAYLOAD;
+	attr->nla_len = nla_attr_size(payload_len);
+	if (skb_copy_bits(skb, 0, nla_data(attr), payload_len))
+		goto nla_put_failure;
+
+out:
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static struct net_dm_hw_metadata *
+net_dm_hw_metadata_clone(const struct net_dm_hw_metadata *hw_metadata)
+{
+	struct net_dm_hw_metadata *n_hw_metadata;
+	const char *trap_group_name;
+	const char *trap_name;
+
+	n_hw_metadata = kmalloc(sizeof(*hw_metadata), GFP_ATOMIC);
+	if (!n_hw_metadata)
+		return NULL;
+
+	trap_group_name = kmemdup(hw_metadata->trap_group_name,
+				  strlen(hw_metadata->trap_group_name) + 1,
+				  GFP_ATOMIC | __GFP_ZERO);
+	if (!trap_group_name)
+		goto free_hw_metadata;
+	n_hw_metadata->trap_group_name = trap_group_name;
+
+	trap_name = kmemdup(hw_metadata->trap_name,
+			    strlen(hw_metadata->trap_name) + 1,
+			    GFP_ATOMIC | __GFP_ZERO);
+	if (!trap_name)
+		goto free_trap_group;
+	n_hw_metadata->trap_name = trap_name;
+
+	n_hw_metadata->input_dev = hw_metadata->input_dev;
+	if (n_hw_metadata->input_dev)
+		dev_hold(n_hw_metadata->input_dev);
+
+	return n_hw_metadata;
+
+free_trap_group:
+	kfree(trap_group_name);
+free_hw_metadata:
+	kfree(n_hw_metadata);
+	return NULL;
+}
+
+static void
+net_dm_hw_metadata_free(const struct net_dm_hw_metadata *hw_metadata)
+{
+	if (hw_metadata->input_dev)
+		dev_put(hw_metadata->input_dev);
+	kfree(hw_metadata->trap_name);
+	kfree(hw_metadata->trap_group_name);
+	kfree(hw_metadata);
+}
+
+static void net_dm_hw_packet_report(struct sk_buff *skb)
+{
+	struct net_dm_hw_metadata *hw_metadata;
+	struct sk_buff *msg;
+	size_t payload_len;
+	int rc;
+
+	if (skb->data > skb_mac_header(skb))
+		skb_push(skb, skb->data - skb_mac_header(skb));
+	else
+		skb_pull(skb, skb_mac_header(skb) - skb->data);
+
+	payload_len = min_t(size_t, skb->len, NET_DM_MAX_PACKET_SIZE);
+	if (net_dm_trunc_len)
+		payload_len = min_t(size_t, net_dm_trunc_len, payload_len);
+
+	hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
+	msg = nlmsg_new(net_dm_hw_packet_report_size(payload_len, hw_metadata),
+			GFP_KERNEL);
+	if (!msg)
+		goto out;
+
+	rc = net_dm_hw_packet_report_fill(msg, skb, payload_len);
+	if (rc) {
+		nlmsg_free(msg);
+		goto out;
+	}
+
+	genlmsg_multicast(&net_drop_monitor_family, msg, 0, 0, GFP_KERNEL);
+
+out:
+	net_dm_hw_metadata_free(NET_DM_SKB_CB(skb)->hw_metadata);
+	consume_skb(skb);
+}
+
+static void net_dm_hw_packet_work(struct work_struct *work)
+{
+	struct per_cpu_dm_data *hw_data;
+	struct sk_buff_head list;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	hw_data = container_of(work, struct per_cpu_dm_data, dm_alert_work);
+
+	__skb_queue_head_init(&list);
+
+	spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
+	skb_queue_splice_tail_init(&hw_data->drop_queue, &list);
+	spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
+
+	while ((skb = __skb_dequeue(&list)))
+		net_dm_hw_packet_report(skb);
+}
+
+static void
+net_dm_hw_packet_probe(struct sk_buff *skb,
+		       const struct net_dm_hw_metadata *hw_metadata)
+{
+	struct net_dm_hw_metadata *n_hw_metadata;
+	ktime_t tstamp = ktime_get_real();
+	struct per_cpu_dm_data *hw_data;
+	struct sk_buff *nskb;
+	unsigned long flags;
+
+	if (!skb_mac_header_was_set(skb))
+		return;
+
+	nskb = skb_clone(skb, GFP_ATOMIC);
+	if (!nskb)
+		return;
+
+	n_hw_metadata = net_dm_hw_metadata_clone(hw_metadata);
+	if (!n_hw_metadata)
+		goto free;
+
+	NET_DM_SKB_CB(nskb)->hw_metadata = n_hw_metadata;
+	nskb->tstamp = tstamp;
+
+	hw_data = this_cpu_ptr(&dm_hw_cpu_data);
+
+	spin_lock_irqsave(&hw_data->drop_queue.lock, flags);
+	if (skb_queue_len(&hw_data->drop_queue) < net_dm_queue_len)
+		__skb_queue_tail(&hw_data->drop_queue, nskb);
+	else
+		goto unlock_free;
+	spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
+
+	schedule_work(&hw_data->dm_alert_work);
+
+	return;
+
+unlock_free:
+	spin_unlock_irqrestore(&hw_data->drop_queue.lock, flags);
+	u64_stats_update_begin(&hw_data->stats.syncp);
+	hw_data->stats.dropped++;
+	u64_stats_update_end(&hw_data->stats.syncp);
+	net_dm_hw_metadata_free(n_hw_metadata);
+free:
+	consume_skb(nskb);
+}
+
+static const struct net_dm_alert_ops net_dm_alert_packet_ops = {
+	.kfree_skb_probe	= net_dm_packet_trace_kfree_skb_hit,
+	.napi_poll_probe	= net_dm_packet_trace_napi_poll_hit,
+	.work_item_func		= net_dm_packet_work,
+	.hw_work_item_func	= net_dm_hw_packet_work,
+	.hw_probe		= net_dm_hw_packet_probe,
+};
+
+static const struct net_dm_alert_ops *net_dm_alert_ops_arr[] = {
+	[NET_DM_ALERT_MODE_SUMMARY]	= &net_dm_alert_summary_ops,
+	[NET_DM_ALERT_MODE_PACKET]	= &net_dm_alert_packet_ops,
+};
+
+void net_dm_hw_report(struct sk_buff *skb,
+		      const struct net_dm_hw_metadata *hw_metadata)
+{
+	rcu_read_lock();
+
+	if (!monitor_hw)
+		goto out;
+
+	net_dm_alert_ops_arr[net_dm_alert_mode]->hw_probe(skb, hw_metadata);
+
+out:
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(net_dm_hw_report);
+
+static int net_dm_hw_monitor_start(struct netlink_ext_ack *extack)
+{
+	const struct net_dm_alert_ops *ops;
+	int cpu;
+
+	if (monitor_hw) {
+		NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already enabled");
+		return -EAGAIN;
+	}
+
+	ops = net_dm_alert_ops_arr[net_dm_alert_mode];
+
+	if (!try_module_get(THIS_MODULE)) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
+		return -ENODEV;
+	}
+
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
+		struct net_dm_hw_entries *hw_entries;
+
+		INIT_WORK(&hw_data->dm_alert_work, ops->hw_work_item_func);
+		timer_setup(&hw_data->send_timer, sched_send_work, 0);
+		hw_entries = net_dm_hw_reset_per_cpu_data(hw_data);
+		kfree(hw_entries);
+	}
+
+	monitor_hw = true;
+
+	return 0;
+}
+
+static void net_dm_hw_monitor_stop(struct netlink_ext_ack *extack)
+{
+	int cpu;
+
+	if (!monitor_hw)
+		NL_SET_ERR_MSG_MOD(extack, "Hardware monitoring already disabled");
+
+	monitor_hw = false;
+
+	/* After this call returns we are guaranteed that no CPU is processing
+	 * any hardware drops.
+	 */
+	synchronize_rcu();
+
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
+		struct sk_buff *skb;
+
+		del_timer_sync(&hw_data->send_timer);
+		cancel_work_sync(&hw_data->dm_alert_work);
+		while ((skb = __skb_dequeue(&hw_data->drop_queue))) {
+			struct net_dm_hw_metadata *hw_metadata;
+
+			hw_metadata = NET_DM_SKB_CB(skb)->hw_metadata;
+			net_dm_hw_metadata_free(hw_metadata);
+			consume_skb(skb);
+		}
+	}
+
+	module_put(THIS_MODULE);
+}
+
+static int net_dm_trace_on_set(struct netlink_ext_ack *extack)
+{
+	const struct net_dm_alert_ops *ops;
+	int cpu, rc;
+
+	ops = net_dm_alert_ops_arr[net_dm_alert_mode];
+
+	if (!try_module_get(THIS_MODULE)) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to take reference on module");
+		return -ENODEV;
+	}
+
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
+		struct sk_buff *skb;
+
+		INIT_WORK(&data->dm_alert_work, ops->work_item_func);
+		timer_setup(&data->send_timer, sched_send_work, 0);
+		/* Allocate a new per-CPU skb for the summary alert message and
+		 * free the old one which might contain stale data from
+		 * previous tracing.
 		 */
-		list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
-			if (new_stat->dev == NULL) {
-				list_del_rcu(&new_stat->list);
-				kfree_rcu(new_stat, rcu);
-			}
+		skb = reset_per_cpu_data(data);
+		consume_skb(skb);
+	}
+
+	rc = register_trace_kfree_skb(ops->kfree_skb_probe, NULL);
+	if (rc) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to kfree_skb() tracepoint");
+		goto err_module_put;
+	}
+
+	rc = register_trace_napi_poll(ops->napi_poll_probe, NULL);
+	if (rc) {
+		NL_SET_ERR_MSG_MOD(extack, "Failed to connect probe to napi_poll() tracepoint");
+		goto err_unregister_trace;
+	}
+
+	return 0;
+
+err_unregister_trace:
+	unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
+err_module_put:
+	module_put(THIS_MODULE);
+	return rc;
+}
+
+static void net_dm_trace_off_set(void)
+{
+	struct dm_hw_stat_delta *new_stat, *temp;
+	const struct net_dm_alert_ops *ops;
+	int cpu;
+
+	ops = net_dm_alert_ops_arr[net_dm_alert_mode];
+
+	unregister_trace_napi_poll(ops->napi_poll_probe, NULL);
+	unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL);
+
+	tracepoint_synchronize_unregister();
+
+	/* Make sure we do not send notifications to user space after request
+	 * to stop tracing returns.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
+		struct sk_buff *skb;
+
+		del_timer_sync(&data->send_timer);
+		cancel_work_sync(&data->dm_alert_work);
+		while ((skb = __skb_dequeue(&data->drop_queue)))
+			consume_skb(skb);
+	}
+
+	list_for_each_entry_safe(new_stat, temp, &hw_stats_list, list) {
+		if (new_stat->dev == NULL) {
+			list_del_rcu(&new_stat->list);
+			kfree_rcu(new_stat, rcu);
 		}
+	}
+
+	module_put(THIS_MODULE);
+}
+
+static int set_all_monitor_traces(int state, struct netlink_ext_ack *extack)
+{
+	int rc = 0;
 
-		module_put(THIS_MODULE);
+	if (state == trace_state) {
+		NL_SET_ERR_MSG_MOD(extack, "Trace state already set to requested state");
+		return -EAGAIN;
+	}
 
+	switch (state) {
+	case TRACE_ON:
+		rc = net_dm_trace_on_set(extack);
+		break;
+	case TRACE_OFF:
+		net_dm_trace_off_set();
 		break;
 	default:
 		rc = 1;
@@ -288,30 +1141,331 @@ static int set_all_monitor_traces(int state)
 	else
 		rc = -EINPROGRESS;
 
-out_unlock:
-	mutex_unlock(&trace_state_mutex);
-
 	return rc;
 }
 
+static bool net_dm_is_monitoring(void)
+{
+	return trace_state == TRACE_ON || monitor_hw;
+}
+
+static int net_dm_alert_mode_get_from_info(struct genl_info *info,
+					   enum net_dm_alert_mode *p_alert_mode)
+{
+	u8 val;
+
+	val = nla_get_u8(info->attrs[NET_DM_ATTR_ALERT_MODE]);
+
+	switch (val) {
+	case NET_DM_ALERT_MODE_SUMMARY: /* fall-through */
+	case NET_DM_ALERT_MODE_PACKET:
+		*p_alert_mode = val;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int net_dm_alert_mode_set(struct genl_info *info)
+{
+	struct netlink_ext_ack *extack = info->extack;
+	enum net_dm_alert_mode alert_mode;
+	int rc;
+
+	if (!info->attrs[NET_DM_ATTR_ALERT_MODE])
+		return 0;
+
+	rc = net_dm_alert_mode_get_from_info(info, &alert_mode);
+	if (rc) {
+		NL_SET_ERR_MSG_MOD(extack, "Invalid alert mode");
+		return -EINVAL;
+	}
+
+	net_dm_alert_mode = alert_mode;
+
+	return 0;
+}
+
+static void net_dm_trunc_len_set(struct genl_info *info)
+{
+	if (!info->attrs[NET_DM_ATTR_TRUNC_LEN])
+		return;
+
+	net_dm_trunc_len = nla_get_u32(info->attrs[NET_DM_ATTR_TRUNC_LEN]);
+}
+
+static void net_dm_queue_len_set(struct genl_info *info)
+{
+	if (!info->attrs[NET_DM_ATTR_QUEUE_LEN])
+		return;
+
+	net_dm_queue_len = nla_get_u32(info->attrs[NET_DM_ATTR_QUEUE_LEN]);
+}
 
 static int net_dm_cmd_config(struct sk_buff *skb,
 			struct genl_info *info)
 {
-	return -ENOTSUPP;
+	struct netlink_ext_ack *extack = info->extack;
+	int rc;
+
+	if (net_dm_is_monitoring()) {
+		NL_SET_ERR_MSG_MOD(extack, "Cannot configure drop monitor during monitoring");
+		return -EBUSY;
+	}
+
+	rc = net_dm_alert_mode_set(info);
+	if (rc)
+		return rc;
+
+	net_dm_trunc_len_set(info);
+
+	net_dm_queue_len_set(info);
+
+	return 0;
+}
+
+static int net_dm_monitor_start(bool set_sw, bool set_hw,
+				struct netlink_ext_ack *extack)
+{
+	bool sw_set = false;
+	int rc;
+
+	if (set_sw) {
+		rc = set_all_monitor_traces(TRACE_ON, extack);
+		if (rc)
+			return rc;
+		sw_set = true;
+	}
+
+	if (set_hw) {
+		rc = net_dm_hw_monitor_start(extack);
+		if (rc)
+			goto err_monitor_hw;
+	}
+
+	return 0;
+
+err_monitor_hw:
+	if (sw_set)
+		set_all_monitor_traces(TRACE_OFF, extack);
+	return rc;
+}
+
+static void net_dm_monitor_stop(bool set_sw, bool set_hw,
+				struct netlink_ext_ack *extack)
+{
+	if (set_hw)
+		net_dm_hw_monitor_stop(extack);
+	if (set_sw)
+		set_all_monitor_traces(TRACE_OFF, extack);
 }
 
 static int net_dm_cmd_trace(struct sk_buff *skb,
 			struct genl_info *info)
 {
+	bool set_sw = !!info->attrs[NET_DM_ATTR_SW_DROPS];
+	bool set_hw = !!info->attrs[NET_DM_ATTR_HW_DROPS];
+	struct netlink_ext_ack *extack = info->extack;
+
+	/* To maintain backward compatibility, we start / stop monitoring of
+	 * software drops if no flag is specified.
+	 */
+	if (!set_sw && !set_hw)
+		set_sw = true;
+
 	switch (info->genlhdr->cmd) {
 	case NET_DM_CMD_START:
-		return set_all_monitor_traces(TRACE_ON);
+		return net_dm_monitor_start(set_sw, set_hw, extack);
 	case NET_DM_CMD_STOP:
-		return set_all_monitor_traces(TRACE_OFF);
+		net_dm_monitor_stop(set_sw, set_hw, extack);
+		return 0;
 	}
 
-	return -ENOTSUPP;
+	return -EOPNOTSUPP;
+}
+
+static int net_dm_config_fill(struct sk_buff *msg, struct genl_info *info)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			  &net_drop_monitor_family, 0, NET_DM_CMD_CONFIG_NEW);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	if (nla_put_u8(msg, NET_DM_ATTR_ALERT_MODE, net_dm_alert_mode))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NET_DM_ATTR_TRUNC_LEN, net_dm_trunc_len))
+		goto nla_put_failure;
+
+	if (nla_put_u32(msg, NET_DM_ATTR_QUEUE_LEN, net_dm_queue_len))
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static int net_dm_cmd_config_get(struct sk_buff *skb, struct genl_info *info)
+{
+	struct sk_buff *msg;
+	int rc;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	rc = net_dm_config_fill(msg, info);
+	if (rc)
+		goto free_msg;
+
+	return genlmsg_reply(msg, info);
+
+free_msg:
+	nlmsg_free(msg);
+	return rc;
+}
+
+static void net_dm_stats_read(struct net_dm_stats *stats)
+{
+	int cpu;
+
+	memset(stats, 0, sizeof(*stats));
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu);
+		struct net_dm_stats *cpu_stats = &data->stats;
+		unsigned int start;
+		u64 dropped;
+
+		do {
+			start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
+			dropped = cpu_stats->dropped;
+		} while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
+
+		stats->dropped += dropped;
+	}
+}
+
+static int net_dm_stats_put(struct sk_buff *msg)
+{
+	struct net_dm_stats stats;
+	struct nlattr *attr;
+
+	net_dm_stats_read(&stats);
+
+	attr = nla_nest_start(msg, NET_DM_ATTR_STATS);
+	if (!attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
+			      stats.dropped, NET_DM_ATTR_PAD))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, attr);
+	return -EMSGSIZE;
+}
+
+static void net_dm_hw_stats_read(struct net_dm_stats *stats)
+{
+	int cpu;
+
+	memset(stats, 0, sizeof(*stats));
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_dm_data *hw_data = &per_cpu(dm_hw_cpu_data, cpu);
+		struct net_dm_stats *cpu_stats = &hw_data->stats;
+		unsigned int start;
+		u64 dropped;
+
+		do {
+			start = u64_stats_fetch_begin_irq(&cpu_stats->syncp);
+			dropped = cpu_stats->dropped;
+		} while (u64_stats_fetch_retry_irq(&cpu_stats->syncp, start));
+
+		stats->dropped += dropped;
+	}
+}
+
+static int net_dm_hw_stats_put(struct sk_buff *msg)
+{
+	struct net_dm_stats stats;
+	struct nlattr *attr;
+
+	net_dm_hw_stats_read(&stats);
+
+	attr = nla_nest_start(msg, NET_DM_ATTR_HW_STATS);
+	if (!attr)
+		return -EMSGSIZE;
+
+	if (nla_put_u64_64bit(msg, NET_DM_ATTR_STATS_DROPPED,
+			      stats.dropped, NET_DM_ATTR_PAD))
+		goto nla_put_failure;
+
+	nla_nest_end(msg, attr);
+
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, attr);
+	return -EMSGSIZE;
+}
+
+static int net_dm_stats_fill(struct sk_buff *msg, struct genl_info *info)
+{
+	void *hdr;
+	int rc;
+
+	hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+			  &net_drop_monitor_family, 0, NET_DM_CMD_STATS_NEW);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	rc = net_dm_stats_put(msg);
+	if (rc)
+		goto nla_put_failure;
+
+	rc = net_dm_hw_stats_put(msg);
+	if (rc)
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return -EMSGSIZE;
+}
+
+static int net_dm_cmd_stats_get(struct sk_buff *skb, struct genl_info *info)
+{
+	struct sk_buff *msg;
+	int rc;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	rc = net_dm_stats_fill(msg, info);
+	if (rc)
+		goto free_msg;
+
+	return genlmsg_reply(msg, info);
+
+free_msg:
+	nlmsg_free(msg);
+	return rc;
 }
 
 static int dropmon_net_event(struct notifier_block *ev_block,
@@ -330,12 +1484,12 @@ static int dropmon_net_event(struct notifier_block *ev_block,
 
 		new_stat->dev = dev;
 		new_stat->last_rx = jiffies;
-		mutex_lock(&trace_state_mutex);
+		mutex_lock(&net_dm_mutex);
 		list_add_rcu(&new_stat->list, &hw_stats_list);
-		mutex_unlock(&trace_state_mutex);
+		mutex_unlock(&net_dm_mutex);
 		break;
 	case NETDEV_UNREGISTER:
-		mutex_lock(&trace_state_mutex);
+		mutex_lock(&net_dm_mutex);
 		list_for_each_entry_safe(new_stat, tmp, &hw_stats_list, list) {
 			if (new_stat->dev == dev) {
 				new_stat->dev = NULL;
@@ -346,18 +1500,28 @@ static int dropmon_net_event(struct notifier_block *ev_block,
 				}
 			}
 		}
-		mutex_unlock(&trace_state_mutex);
+		mutex_unlock(&net_dm_mutex);
 		break;
 	}
 out:
 	return NOTIFY_DONE;
 }
 
+static const struct nla_policy net_dm_nl_policy[NET_DM_ATTR_MAX + 1] = {
+	[NET_DM_ATTR_UNSPEC] = { .strict_start_type = NET_DM_ATTR_UNSPEC + 1 },
+	[NET_DM_ATTR_ALERT_MODE] = { .type = NLA_U8 },
+	[NET_DM_ATTR_TRUNC_LEN] = { .type = NLA_U32 },
+	[NET_DM_ATTR_QUEUE_LEN] = { .type = NLA_U32 },
+	[NET_DM_ATTR_SW_DROPS]	= {. type = NLA_FLAG },
+	[NET_DM_ATTR_HW_DROPS]	= {. type = NLA_FLAG },
+};
+
 static const struct genl_ops dropmon_ops[] = {
 	{
 		.cmd = NET_DM_CMD_CONFIG,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = net_dm_cmd_config,
+		.flags = GENL_ADMIN_PERM,
 	},
 	{
 		.cmd = NET_DM_CMD_START,
@@ -369,12 +1533,38 @@ static const struct genl_ops dropmon_ops[] = {
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = net_dm_cmd_trace,
 	},
+	{
+		.cmd = NET_DM_CMD_CONFIG_GET,
+		.doit = net_dm_cmd_config_get,
+	},
+	{
+		.cmd = NET_DM_CMD_STATS_GET,
+		.doit = net_dm_cmd_stats_get,
+	},
 };
 
+static int net_dm_nl_pre_doit(const struct genl_ops *ops,
+			      struct sk_buff *skb, struct genl_info *info)
+{
+	mutex_lock(&net_dm_mutex);
+
+	return 0;
+}
+
+static void net_dm_nl_post_doit(const struct genl_ops *ops,
+				struct sk_buff *skb, struct genl_info *info)
+{
+	mutex_unlock(&net_dm_mutex);
+}
+
 static struct genl_family net_drop_monitor_family __ro_after_init = {
 	.hdrsize        = 0,
 	.name           = "NET_DM",
 	.version        = 2,
+	.maxattr	= NET_DM_ATTR_MAX,
+	.policy		= net_dm_nl_policy,
+	.pre_doit	= net_dm_nl_pre_doit,
+	.post_doit	= net_dm_nl_post_doit,
 	.module		= THIS_MODULE,
 	.ops		= dropmon_ops,
 	.n_ops		= ARRAY_SIZE(dropmon_ops),
@@ -386,9 +1576,57 @@ static struct notifier_block dropmon_net_notifier = {
 	.notifier_call = dropmon_net_event
 };
 
-static int __init init_net_drop_monitor(void)
+static void __net_dm_cpu_data_init(struct per_cpu_dm_data *data)
+{
+	spin_lock_init(&data->lock);
+	skb_queue_head_init(&data->drop_queue);
+	u64_stats_init(&data->stats.syncp);
+}
+
+static void __net_dm_cpu_data_fini(struct per_cpu_dm_data *data)
+{
+	WARN_ON(!skb_queue_empty(&data->drop_queue));
+}
+
+static void net_dm_cpu_data_init(int cpu)
+{
+	struct per_cpu_dm_data *data;
+
+	data = &per_cpu(dm_cpu_data, cpu);
+	__net_dm_cpu_data_init(data);
+}
+
+static void net_dm_cpu_data_fini(int cpu)
 {
 	struct per_cpu_dm_data *data;
+
+	data = &per_cpu(dm_cpu_data, cpu);
+	/* At this point, we should have exclusive access
+	 * to this struct and can free the skb inside it.
+	 */
+	consume_skb(data->skb);
+	__net_dm_cpu_data_fini(data);
+}
+
+static void net_dm_hw_cpu_data_init(int cpu)
+{
+	struct per_cpu_dm_data *hw_data;
+
+	hw_data = &per_cpu(dm_hw_cpu_data, cpu);
+	__net_dm_cpu_data_init(hw_data);
+}
+
+static void net_dm_hw_cpu_data_fini(int cpu)
+{
+	struct per_cpu_dm_data *hw_data;
+
+	hw_data = &per_cpu(dm_hw_cpu_data, cpu);
+	kfree(hw_data->hw_entries);
+	__net_dm_cpu_data_fini(hw_data);
+}
+
+static int __init init_net_drop_monitor(void)
+{
 	int cpu, rc;
 
 	pr_info("Initializing network drop monitor service\n");
@@ -414,14 +1652,10 @@ static int __init init_net_drop_monitor(void)
 	rc = 0;
 
 	for_each_possible_cpu(cpu) {
-		data = &per_cpu(dm_cpu_data, cpu);
-		INIT_WORK(&data->dm_alert_work, send_dm_alert);
-		timer_setup(&data->send_timer, sched_send_work, 0);
-		spin_lock_init(&data->lock);
-		reset_per_cpu_data(data);
+		net_dm_cpu_data_init(cpu);
+		net_dm_hw_cpu_data_init(cpu);
 	}
 
-
 	goto out;
 
 out_unreg:
@@ -432,7 +1666,6 @@ out:
 
 static void exit_net_drop_monitor(void)
 {
-	struct per_cpu_dm_data *data;
 	int cpu;
 
 	BUG_ON(unregister_netdevice_notifier(&dropmon_net_notifier));
@@ -440,19 +1673,11 @@ static void exit_net_drop_monitor(void)
 	/*
 	 * Because of the module_get/put we do in the trace state change path
 	 * we are guarnateed not to have any current users when we get here
-	 * all we need to do is make sure that we don't have any running timers
-	 * or pending schedule calls
 	 */
 
 	for_each_possible_cpu(cpu) {
-		data = &per_cpu(dm_cpu_data, cpu);
-		del_timer_sync(&data->send_timer);
-		cancel_work_sync(&data->dm_alert_work);
-		/*
-		 * At this point, we should have exclusive access
-		 * to this struct and can free the skb inside it
-		 */
-		kfree_skb(data->skb);
+		net_dm_hw_cpu_data_fini(cpu);
+		net_dm_cpu_data_fini(cpu);
 	}
 
 	BUG_ON(genl_unregister_family(&net_drop_monitor_family));