[KERNEL] Refactor and extend sysfs (add data the server will need in proxy mode)

[SERVER] Use MSG_MORE instead of cork/uncork to save two syscalls
[KERNEL] Fail-Counter for alt servers, ignore servers that fail too often
[KERNEL] Add new alt servers to list, instead of replacing the old list
[*] Add CMD_LATEST_RID to tell client about new revisions

5 files changed, 48 insertions, 26 deletions

diff --git a/src/server/ipc.c b/src/server/ipc.c
index 5da811c..ece6f07 100644
--- a/src/server/ipc.c
+++ b/src/server/ipc.c
@@ -403,9 +403,10 @@ void dnbd3_ipc_send(int cmd)
 
     if (cmd == IPC_INFO && header.size > 0)
     {
-        char* buf = malloc(header.size);
+        char* buf = malloc(header.size+1);
     	size = recv(client_sock, buf, header.size, MSG_WAITALL);
     	xmlDocPtr doc = xmlReadMemory(buf, size, "noname.xml", NULL, 0);
+    	buf[header.size] = 0;
 
 		if (doc)
 		{
@@ -479,9 +480,10 @@ void dnbd3_ipc_send(int cmd)
 
 //			xmlDocDump(stdout, doc);
 
-		} else
+		}
+		else
 		{
-			printf("ERROR: Failed to parse reply\n");
+			printf("ERROR: Failed to parse reply\n-----------\n%s\n-------------\n", buf);
 		}
 
     }
diff --git a/src/server/net.c b/src/server/net.c
index c145beb..49cfb24 100644
--- a/src/server/net.c
+++ b/src/server/net.c
@@ -39,7 +39,7 @@
 #include "../config.h"
 
 
-static char recv_request_header(int sock, dnbd3_request_t *request)
+static inline char recv_request_header(int sock, dnbd3_request_t *request)
 {
 	int ret;
 	// Read request header from socket
@@ -62,10 +62,13 @@ static char recv_request_header(int sock, dnbd3_request_t *request)
     	memlogf("[WARNING] Client tries to send a packet of type %d with %d bytes payload. Dropping client.", (int)request->cmd, (int)request->size);
     	return 0;
     }
+#ifdef _DEBUG
+    	if (_fake_delay) usleep(_fake_delay);
+#endif
     return 1;
 }
 
-static char recv_request_payload(int sock, uint32_t size, serialized_buffer_t *payload)
+static inline char recv_request_payload(int sock, uint32_t size, serialized_buffer_t *payload)
 {
 	if (size == 0)
 	{
@@ -87,10 +90,11 @@ static char recv_request_payload(int sock, uint32_t size, serialized_buffer_t *p
 	return 1;
 }
 
-static char send_reply(int sock, dnbd3_reply_t *reply, void *payload)
+static inline char send_reply(int sock, dnbd3_reply_t *reply, void *payload)
 {
+	const unsigned int size = reply->size;
 	fixup_reply(*reply);
-	if (!payload || reply->size == 0)
+	if (!payload || size == 0)
 	{
 		if (send(sock, reply, sizeof(dnbd3_reply_t), MSG_WAITALL) != sizeof(dnbd3_reply_t))
 		{
@@ -104,10 +108,10 @@ static char send_reply(int sock, dnbd3_reply_t *reply, void *payload)
 		iov[0].iov_base = reply;
 		iov[0].iov_len = sizeof(dnbd3_reply_t);
 		iov[1].iov_base = payload;
-		iov[1].iov_len = reply->size;
-		if (writev(sock, iov, 2) != sizeof(dnbd3_reply_t) + reply->size)
+		iov[1].iov_len = size;
+		if (writev(sock, iov, 2) != sizeof(dnbd3_reply_t) + size)
 		{
-			printf("[DEBUG] Send failed (reply with payload of %d bytes)\n", (int)reply->size);
+			printf("[DEBUG] Send failed (reply with payload of %u bytes)\n", size);
 			return 0;
 		}
 	}
@@ -120,9 +124,6 @@ void *dnbd3_handle_query(void *dnbd3_client)
     dnbd3_request_t request;
     dnbd3_reply_t reply;
 
-    const int cork = 1;
-    const int uncork = 0;
-
     dnbd3_image_t *image = NULL;
     int image_file = -1, image_cache = -1;
 
@@ -216,7 +217,6 @@ void *dnbd3_handle_query(void *dnbd3_client)
 
     if (image) while (recv_request_header(client->sock, &request))
     {
-
         switch (request.cmd)
         {
 
@@ -246,12 +246,16 @@ void *dnbd3_handle_query(void *dnbd3_client)
             	break;
             }
 
-            // TODO: Try MSG_MORE instead of cork+uncork if performance ever becomes an issue..
-            setsockopt(client->sock, SOL_TCP, TCP_CORK, &cork, sizeof(cork));
             reply.cmd = CMD_GET_BLOCK;
             reply.size = request.size;
             reply.handle = request.handle;
-            send_reply(client->sock, &reply, NULL);
+
+        	fixup_reply(reply);
+			if (send(client->sock, &reply, sizeof(dnbd3_reply_t), MSG_MORE) != sizeof(dnbd3_reply_t))
+			{
+				printf("[DEBUG] Sending CMD_GET_BLOCK header failed\n");
+				return 0;
+			}
 
             if (request.size == 0) // Request for 0 bytes, done after sending header
             	break;
@@ -264,8 +268,6 @@ void *dnbd3_handle_query(void *dnbd3_client)
                 	printf("[ERROR] sendfile failed (image to net)\n");
                 	close(client->sock);
                 }
-
-                setsockopt(client->sock, SOL_TCP, TCP_CORK, &uncork, sizeof(uncork));
                 break;
             }
 
@@ -343,8 +345,6 @@ void *dnbd3_handle_query(void *dnbd3_client)
             	memlogf("[ERROR] sendfile failed (cache to net)\n");
             	close(client->sock);
             }
-
-            setsockopt(client->sock, SOL_TCP, TCP_CORK, &uncork, sizeof(uncork));
             break;
 
 
@@ -353,7 +353,7 @@ void *dnbd3_handle_query(void *dnbd3_client)
             num = 0;
             for (i = 0; i < NUMBER_SERVERS; i++)
             {
-                if (image->servers[i].addrtype == 0 || image->servers[i].failures > 200) continue;
+                if (image->servers[i].hostaddrtype == 0 || image->servers[i].failures > 200) continue;
                 memcpy(server_list + num++, image->servers + i, sizeof(dnbd3_server_entry_t));
             }
             reply.cmd = CMD_GET_SERVERS;
diff --git a/src/server/server.c b/src/server/server.c
index b2a36a5..965c368 100644
--- a/src/server/server.c
+++ b/src/server/server.c
@@ -37,6 +37,9 @@
 #include "memlog.h"
 
 int _sock;
+#ifdef _DEBUG
+int _fake_delay = 0;
+#endif
 pthread_spinlock_t _spinlock;
 
 GSList *_dnbd3_clients = NULL;
@@ -48,6 +51,9 @@ void dnbd3_print_help(char* argv_0)
     printf("Usage: %s [OPTIONS]...\n", argv_0);
     printf("Start the DNBD3 server\n");
     printf("-f or --file \t\t Configuration file (default /etc/dnbd3-server.conf)\n");
+#ifdef _DEBUG
+    printf("-d or --delay \t\t Add a fake network delay of X µs\n");
+#endif
     printf("-n or --nodaemon \t Start server in foreground\n");
     printf("-r or --reload \t\t Reload configuration file\n");
     printf("-s or --stop \t\t Stop running dnbd3-server\n");
@@ -119,10 +125,11 @@ int main(int argc, char* argv[])
     int demonize = 1;
     int opt = 0;
     int longIndex = 0;
-    static const char *optString = "f:nrsiHV?";
+    static const char *optString = "f:d:nrsiHV?";
     static const struct option longOpts[] =
     {
     { "file", required_argument, NULL, 'f' },
+    { "delay", required_argument, NULL, 'd' },
     { "nodaemon", no_argument, NULL, 'n' },
     { "reload", no_argument, NULL, 'r' },
     { "stop", no_argument, NULL, 's' },
@@ -137,8 +144,16 @@ int main(int argc, char* argv[])
         switch (opt)
         {
         case 'f':
-            _config_file_name = optarg;
+            _config_file_name = strdup(optarg);
             break;
+        case 'd':
+#ifdef _DEBUG
+        	_fake_delay = atoi(optarg);
+        	break;
+#else
+        	printf("This option is only available in debug builds.\n\n");
+        	return EXIT_FAILURE;
+#endif
         case 'n':
             demonize = 0;
             break;
diff --git a/src/server/server.h b/src/server/server.h
index 69d597b..7e19f27 100644
--- a/src/server/server.h
+++ b/src/server/server.h
@@ -56,6 +56,11 @@ extern pthread_spinlock_t _spinlock;
 extern char *_config_file_name;
 extern GSList *_dnbd3_images; // of dnbd3_image_t
 
+
+#ifdef _DEBUG
+extern int _fake_delay;
+#endif
+
 void dnbd3_cleanup();
 
 #endif /* SERVER_H_ */
diff --git a/src/server/utils.c b/src/server/utils.c
index 15e51f8..3fe1900 100644
--- a/src/server/utils.c
+++ b/src/server/utils.c
@@ -260,11 +260,11 @@ void dnbd3_load_config(char *file)
         gchar **servers = g_key_file_get_string_list(gkf, groups[i], "servers", &num_servers, NULL);
         if (servers) for (k = 0, j = 0; j < MIN(num_servers, NUMBER_SERVERS); ++j)
         {
-        	if (parse_address(servers[j], &(image->servers[k].addrtype), image->servers[k].ipaddr, &(image->servers[k].port)))
+        	if (parse_address(servers[j], &(image->servers[k].hostaddrtype), image->servers[k].hostaddr, &(image->servers[k].port)))
         	{
         		++k; continue;
         	}
-        	image->servers[k].addrtype = 0;
+        	image->servers[k].hostaddrtype = 0;
         }
         g_strfreev(servers);