app-layer: extract out a simple function type to simple header

Extract a simple function function to a simple header with no circular
dependencies.

Next we'll use bindgen to generate Rust bindings for this function.

Ticket: OISF#7341

src/Makefile.am

@@ -19,6 +19,7 @@ noinst_HEADERS = \
 	app-layer-dnp3-objects.h \
 	app-layer-events.h \
 	app-layer-expectation.h \
+	app-layer-ext.h \
 	app-layer-frames.h \
 	app-layer-ftp.h \
 	app-layer.h \

src/app-layer-ext.h

@@ -0,0 +1,8 @@
+#ifndef SURICATA_APP_LAYER_EXT_H
+#define SURICATA_APP_LAYER_EXT_H
+
+#include <stdint.h>
+
+typedef int (*SCAppLayerStateGetProgressFn)(void *alstate, uint8_t direction);
+
+#endif /* SURICATA_APP_LAYER_EXT_H */

src/app-layer-register.h

@@ -25,6 +25,7 @@
 #define SURICATA_APP_LAYER_REGISTER_H
 
 #include "app-layer-detect-proto.h"
+#include "app-layer-ext.h"
 
 typedef struct AppLayerParser {
     const char *name;
@@ -49,7 +50,7 @@ typedef struct AppLayerParser {
 
     const int complete_ts;
     const int complete_tc;
-    int (*StateGetProgress)(void *alstate, uint8_t direction);
+    SCAppLayerStateGetProgressFn StateGetProgress;
 
     int (*StateGetEventInfo)(const char *event_name,
                              int *event_id, AppLayerEventType *event_type);