1 files changed, 73 insertions, 0 deletions
diff --git a/kernel/net.h b/kernel/net.h
new file mode 100644
index 0000000..cdd7996
--- /dev/null
+++ b/kernel/net.h
@@ -0,0 +1,73 @@
+#ifndef LINUX_DNBD_NET_H
+#define LINUX_DNBD_NET_H	1
+
+#include <linux/spinlock.h>
+#include <asm/semaphore.h>
+#include <linux/list.h>
+#include <linux/param.h>
+#include <linux/jiffies.h>
+
+#define 	SERVERS_MAX		8
+#define		SERVER_STALLED		-1
+#define		SERVER_INACTIVE		0
+#define		SERVER_ACTIVE		1
+
+/* limits and other constants for SRTT calculations */
+#define		TIMEOUT_MIN		1
+#define		TIMEOUT_MAX		HZ / 4
+#define		TIMEOUT_STALLED		5 * HZ
+#define		TIMEOUT_SHIFT		2
+
+/* beta is 99% (990/1000) */
+#define		SRTT_BETA		990
+#define		SRTT_BETA_BASE		1000	
+#define		SRTT_SHIFT		10
+
+/* normalize weights to 255 as there is no float arithmetic in kernel */
+#define		WEIGHT_NORMAL		((1<<8)-1)
+#define		WEIGHT_FACTOR		(1<<20)
+
+#define dnbd_rx_update(servers, id) \
+if ((id > 0) && (id <= SERVERS_MAX)) servers.serverlist[id-1].last_rx = jiffies;
+	
+#define dnbd_tx_update(servers, id) \
+if ((id > 0) && (id <= SERVERS_MAX)) servers.serverlist[id-1].last_tx = jiffies;
+
+/* characteristics of a server */
+struct dnbd_server {
+	int id;
+	int state;
+	int srtt;
+	int weight;
+	unsigned long last_rx;		/* in jiffies */
+	unsigned long last_tx;		/* in jiffies */
+};
+
+typedef struct dnbd_server dnbd_server_t;
+
+/* common server information and helper variables */
+struct dnbd_servers {
+	struct dnbd_server *serverlist;
+	struct dnbd_server *server;
+	spinlock_t lock;
+	struct semaphore sema;
+	int timeout_min;
+	int timeout_max;
+	int timeout_stalled;
+	int asrtt;
+	int count;
+};
+
+typedef struct dnbd_servers dnbd_servers_t;
+	
+/* functions */
+int dnbd_set_serverid(dnbd_servers_t * servers, int id);
+int dnbd_next_server(dnbd_servers_t * servers);
+void dnbd_rem_servers(dnbd_servers_t * servers);
+void dnbd_rtt_server(dnbd_servers_t * servers, int id, int rtt);
+int dnbd_servers_init(dnbd_servers_t *servers);
+void dnbd_servers_weight(dnbd_servers_t * servers);
+int dnbd_show_servers(dnbd_servers_t * servers, void *buf, int size);
+void dnbd_clean_servers(dnbd_servers_t * servers);
+	
+#endif