Optimize GTP utility functions

src/packet/gtp_utils.h

@@ -0,0 +1,51 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "gtp1_utils.h"
+#include "gtp2_utils.h"
+
+// return GTP version 0 or 1
+// return 255 if not GTP
+static inline uint8_t peek_gtp_version(const char *data, uint16_t len)
+{
+    if (data == NULL || len == 0)
+    {
+        return 255;
+    }
+
+    return ((*(uint8_t *)data) >> 5) & 0x07;
+}
+
+static inline uint16_t calc_gtp_hdr_len(const char *data, uint32_t len)
+{
+    switch (peek_gtp_version(data, len))
+    {
+    case 1:
+        return calc_gtp1_hdr_len(data, len);
+    case 2:
+        return calc_gtp2_hdr_len(data, len);
+    default:
+        return 0;
+    }
+}
+
+static inline int gtp_hdr_to_str(const char *hdr, uint16_t len, char *buf, size_t size)
+{
+    switch (peek_gtp_version(hdr, len))
+    {
+    case 1:
+        return gtp1_hdr_to_str((const struct gtp1_hdr *)hdr, buf, size);
+    case 2:
+        return gtp2_hdr_to_str((const struct gtp2_hdr *)hdr, buf, size);
+    default:
+        return 0;
+    }
+}
+
+#ifdef __cplusplus
+}
+#endif