MT#57093 introduce kernel module version check

Check all the struct sizes as part of the startup NOOP command, to try
to catch incompatible kernel module versions.

Change-Id: Ib617878e1e5a813de199c5405db3680c1e4d3351

daemon/kernel.c

@@ -75,7 +75,24 @@ static int kernel_open_table(unsigned int id) {
 		return -1;
 
 	cmd.cmd = REMG_NOOP;
-	cmd.noop.last_cmd = __REMG_LAST;
+
+	cmd.noop = (struct rtpengine_noop_info) {
+		.last_cmd = __REMG_LAST,
+		.msg_size = {
+			[REMG_NOOP] = sizeof(struct rtpengine_command_noop),
+			[REMG_ADD_TARGET] = sizeof(struct rtpengine_command_add_target),
+			[REMG_DEL_TARGET] = sizeof(struct rtpengine_command_del_target),
+			[REMG_ADD_DESTINATION] = sizeof(struct rtpengine_command_destination),
+			[REMG_ADD_CALL] = sizeof(struct rtpengine_command_add_call),
+			[REMG_DEL_CALL] = sizeof(struct rtpengine_command_del_call),
+			[REMG_ADD_STREAM] = sizeof(struct rtpengine_command_add_stream),
+			[REMG_DEL_STREAM] = sizeof(struct rtpengine_command_del_stream),
+			[REMG_PACKET] = sizeof(struct rtpengine_command_packet),
+			[REMG_GET_STATS] = sizeof(struct rtpengine_command_stats),
+			[REMG_GET_RESET_STATS] = sizeof(struct rtpengine_command_stats),
+		},
+	};
+
 	i = write(fd, &cmd, sizeof(cmd));
 	if (i <= 0)
 		goto fail;

kernel-module/xt_RTPENGINE.c

@@ -3550,6 +3550,7 @@ static inline ssize_t proc_control_read_write(struct file *file, char __user *ub
 	enum rtpengine_command cmd;
 	char scratchbuf[512];
 	size_t readlen, writelen, writeoffset;
+	int i;
 
 	union {
 		struct rtpengine_command_noop *noop;
@@ -3625,6 +3626,9 @@ static inline ssize_t proc_control_read_write(struct file *file, char __user *ub
 		case REMG_NOOP:
 			if (msg.noop->noop.last_cmd != __REMG_LAST)
 				err = -ERANGE;
+			for (i = 0; i < __REMG_LAST; i++)
+				if (msg.noop->noop.msg_size[i] != min_req_sizes[i])
+					err = -EMSGSIZE;
 			break;
 
 		case REMG_ADD_TARGET:

kernel-module/xt_RTPENGINE.h

@@ -174,10 +174,6 @@ struct rtpengine_stats_info {
 	struct rtpengine_ssrc_stats	ssrc_stats[RTPE_NUM_SSRC_TRACKING];
 };
 
-struct rtpengine_noop_info {
-	int				last_cmd;
-};
-
 enum rtpengine_command {
 	REMG_NOOP = 1,
 	REMG_ADD_TARGET,
@@ -194,6 +190,11 @@ enum rtpengine_command {
 	__REMG_LAST
 };
 
+struct rtpengine_noop_info {
+	int				last_cmd;
+	size_t				msg_size[__REMG_LAST];
+};
+
 struct rtpengine_command_noop {
 	enum rtpengine_command		cmd;
 	struct rtpengine_noop_info	noop;