From 1955ee6dae79b75277df0aa13f7e341593f925b2 Mon Sep 17 00:00:00 2001
From: 7u83 <7u83@mail.ru>
Date: Thu, 28 Jul 2022 01:38:42 +0200
Subject: [PATCH] new decode message funtion

---
 src/cw/cw_decode_msg.c | 103 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 src/cw/cw_decode_msg.c

diff --git a/src/cw/cw_decode_msg.c b/src/cw/cw_decode_msg.c
new file mode 100644
index 00000000..3a711be3
--- /dev/null
+++ b/src/cw/cw_decode_msg.c
@@ -0,0 +1,103 @@
+#include "cw.h"
+#include "dbg.h"
+#include "log.h"
+
+
+int cw_decode_element(struct cw_ElemHandlerParams *params, int proto,
+		      int vendor, int elem_id, uint8_t * data, int len)
+{
+
+	struct cw_ElemHandler *handler;
+	struct cw_ElemData *elem_data, elem_data_search;
+	int rc;
+
+	params->elem = NULL;
+
+	/* try to retrieve a handler for this message element */
+	handler =
+	    cw_msgset_get_elemhandler(params->msgset, proto, vendor,
+				      elem_id);
+	if (!handler) {
+
+		cw_dbg(DBG_ELEM_ERR,
+		       "Unrecognized message element: %d, ignoring", elem_id);
+		return CAPWAP_RESULT_UNRECOGNIZED_MESSAGE_ELEMENT;
+	}
+
+	/* check if this message element in the current message allowed */
+	elem_data_search.id = elem_id;
+	elem_data_search.proto = proto;
+	elem_data_search.vendor = vendor;
+	elem_data = mavl_get(params->msgdata->elements_tree, &elem_data_search);
+	if (!elem_data) {
+		cw_dbg(DBG_ELEM_ERR, "Element %d - %s, not allowed here",
+		       elem_id, handler->name);
+		return CAPWAP_RESULT_UNRECOGNIZED_MESSAGE_ELEMENT;
+	}
+
+	/* check the length of the message */
+	if (len < handler->min_len) {
+		cw_dbg(DBG_ELEM_ERR,
+		       "%d (%s) message element too short, len=%d, min len=%d",
+		       handler->id, handler->name, len, handler->min_len);
+		return -1;
+	}
+
+
+	if (elem_data->mand) {
+		mavl_add_str(params->mand_found, handler->key);
+	}
+
+
+	if (len > handler->max_len && handler->max_len) {
+		cw_dbg(DBG_ELEM_ERR,
+		       "%d (%s) message element too big, len=%d, max len=%d",
+		       handler->id, handler->name, len, handler->max_len);
+		/* TODO XXX truncate the element instead of return */
+		return -1;
+	}
+
+	cw_dbg_elem(DBG_ELEM_IN, NULL, params->msgdata->type, handler,
+		    data, len);
+
+	if (handler->get == NULL) {
+		cw_log(LOG_ERR, "No get method defined for %d %s", handler->id,
+		       handler->name);
+		return CAPWAP_RESULT_UNRECOGNIZED_MESSAGE_ELEMENT;
+	}
+	rc = handler->get(handler, params, data, len);
+
+
+	return rc;
+}
+
+
+int cw_decode_elements(uint8_t * elems_ptr, int elems_len)
+{
+	uint8_t *elem;
+
+	/* iterate through message elements */
+	cw_foreach_elem(elem, elems_ptr, elems_len) {
+		int rc;
+
+
+		struct cw_ElemHandlerParams params;
+		int elem_len, elem_id, max_len;
+		uint8_t *elem_data;
+
+
+		elem_len = cw_get_elem_len(elem);
+		elem_data = cw_get_elem_data(elem);
+		elem_id = cw_get_elem_id(elem);
+
+		max_len = elems_len - (elem_data - elems_ptr);
+		if (elem_len > max_len) {
+			cw_dbg(DBG_RFC,
+			       "Messag element claims size of %d bytes, but only %d bytes are left in the payload, truncating.",
+			       elem_len, max_len - 4);
+		}
+
+
+
+	}
+}