[KERNEL, CLIENT]: submit and probe multiple dnbd3-server with ioctl OPEN

The ioctl OPEN call for DNBD3 devices exposed by the dnbd3 Linux kernel
module, is extended with a fixed array of dnbd3 hosts. The fixed array
allows the dnbd3-client to submit host information (IP address and port)
of multiple dnbd3-servers. This information is used to probe all
submitted dnbd3-servers and add them to the alternative dnbd3-server
list. If at least one dnbd3-server is not reachable, the OPEN ioctl call
will abort with an error code.

1 files changed, 5 insertions, 1 deletions

diff --git a/inc/dnbd3/types.h b/inc/dnbd3/types.h
index 63e182c..59bf2d1 100644
--- a/inc/dnbd3/types.h
+++ b/inc/dnbd3/types.h
@@ -128,10 +128,14 @@ typedef struct __attribute__((packed)) dnbd3_host_t
 	dnbd3_af type;        // 1byte (ip version. HOST_IP4 or HOST_IP6. 0 means this struct is empty and should be ignored)
 } dnbd3_host_t;
 
+/* IOCTLs */
+#define MAX_HOSTS_PER_IOCTL NUMBER_SERVERS
+
 typedef struct __attribute__((packed))
 {
 	uint16_t len;
-	dnbd3_host_t host;
+	dnbd3_host_t hosts[MAX_HOSTS_PER_IOCTL];
+	uint8_t hosts_num;
 	uint16_t imgnamelen;
 	char *imgname;
 	int rid;