Network Drop Monitor: Adding drop monitor implementation & Netlink protocol

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>

 include/linux/net_dropmon.h |   56 +++++++++
 net/core/drop_monitor.c     |  263 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 319 insertions(+)
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/net_dropmon.h b/include/linux/net_dropmon.h
new file mode 100644
index 0000000..0217fb8
--- /dev/null
+++ b/include/linux/net_dropmon.h
@@ -0,0 +1,56 @@
+#ifndef __NET_DROPMON_H
+#define __NET_DROPMON_H
+
+#include <linux/netlink.h>
+
+struct net_dm_drop_point {
+	__u8 pc[8];
+	__u32 count;
+};
+
+#define NET_DM_CFG_VERSION  0
+#define NET_DM_CFG_ALERT_COUNT  1
+#define NET_DM_CFG_ALERT_DELAY 2
+#define NET_DM_CFG_MAX 3
+
+struct net_dm_config_entry {
+	__u32 type;
+	__u64 data __attribute__((aligned(8)));
+};
+
+struct net_dm_config_msg {
+	__u32 entries;
+	struct net_dm_config_entry options[0];
+};
+
+struct net_dm_alert_msg {
+	__u32 entries;
+	struct net_dm_drop_point points[0];
+};
+
+struct net_dm_user_msg {
+	union {
+		struct net_dm_config_msg user;
+		struct net_dm_alert_msg alert;
+	} u;
+};
+
+
+/* These are the netlink message types for this protocol */
+
+enum {
+	NET_DM_CMD_UNSPEC = 0,
+	NET_DM_CMD_ALERT,
+	NET_DM_CMD_CONFIG,
+	NET_DM_CMD_START,
+	NET_DM_CMD_STOP,
+	_NET_DM_CMD_MAX,
+};
+
+#define NET_DM_CMD_MAX (_NET_DM_CMD_MAX - 1)
+
+/*
+ * Our group identifiers
+ */
+#define NET_DM_GRP_ALERT 1
+#endif