diff --git a/sys/include/net/ng_pktbuf.h b/sys/include/net/ng_pktbuf.h
index f408c02151c21f83c2ad18760aa3d345c8e5e207..020bcf6ea07fe017c5fd2689cfcd2e9d32a2aff2 100644
--- a/sys/include/net/ng_pktbuf.h
+++ b/sys/include/net/ng_pktbuf.h
@@ -56,34 +56,37 @@ extern "C" {
#define NG_PKTBUF_SIZE (6144)
#endif /* NG_PKTBUF_SIZE */
+/**
+ * @brief Initializes packet buffer module.
+ */
+void ng_pktbuf_init(void);
+
/**
* @brief Adds a new ng_pktsnip_t and its packet to the packet buffer.
*
- * @details This function is very powerful and reflects the unique characterics
- * of ng_pktsnip_t of being reversed for either the sending or
- * receiving context. Because of this the assumtion of the transmission
- * direction, the state of the packet buffer and the values for the
- * members of the resulting ng_pktsnip_t can be very different after
- * execution of this function depending on what parameters you use:
- *
- * * The return value of this function is a @ref ng_pktsnip_t struct referred
- * to as `result`
- * * for most cases the build-up of `result` will be pretty straight forward: Its
- * members will be exactly as the given parameters (ng_pktsnip_t::next of
- * result will be set to @p pkt). If @p pkt is not NULL it and in turn `result`
- * are assumed to be in sending direction. For packet creation (@p pkt == NULL)
- * no assumtions about direction of `result` will be made (since its
- * ng_pktsnip::next will be set to NULL).
- * * if @p pkt != NULL, @p data = `pkt->data`, @p size < `pkt->size` receiving
- * direction is assumed and the following values will be set:
- * * ng_pktsnip_t::next of `result` = `pkt->next`
- * * ng_pktsnip_t::data of `result` = @p data
- * * ng_pktsnip_t::size of `result` = @p size
- * * ng_pktsnip_t::next of @p pkt = `result`
- * * ng_pktsnip_t::data of @p pkt = @p data + @p size
- * * ng_pktsnip_t::size of @p pkt = old size value - @p size
- *
- * graphically this can be represented as follows:
+ * @warning **Do not** change the fields of the ng_pktsnip_t created by this
+ * function externally. This will most likely create memory leaks or
+ * not allowed memory access.
+ *
+ * @param[in] next Next ng_pktsnip_t in the packet. Leave NULL if you
+ * want to create a new packet.
+ * @param[in] data Data of the new ng_pktsnip_t. If @p data is NULL no data
+ * will be inserted into `result`.
+ * @param[in] size Length of @p data. May not be 0.
+ * @param[in] type Protocol type of the ng_pktsnip_t.
+ *
+ * @return Pointer to the packet part that represents the new ng_pktsnip_t.
+ * @return NULL, if no space is left in the packet buffer.
+ * @return NULL, if @p size == 0.
+ */
+ng_pktsnip_t *ng_pktbuf_add(ng_pktsnip_t *next, void *data, size_t size,
+ ng_nettype_t type);
+
+/**
+ * @brief Marks the first @p size bytes in a received packet with a new
+ * packet snip that is appended to the packet.
+ *
+ * Graphically this can be represented as follows:
* @code
* Before After
* ====== =====
@@ -95,36 +98,23 @@ extern "C" {
* \__________pkt->size___________/ \_result->size_/ \__pkt->size__/
* @endcode
*
- * @note **Do not** change the ng_pktsnip_t::data and ng_pktsnip_t::size
- * of a ng_pktsnip_t created by this function externally, except if
- * they both are null or data is not from inside the packet buffer.
- * This will most likely create memory leaks.
+ * @pre @p pkt != NULL && @p size != 0
*
- * @param[in,out] pkt The packet you want to add a ng_pktsnip_t to. Leave
- * NULL if you want to create a new packet. Members may
- * change values; see above.
- * @param[in] data Data of the new ng_pktsnip_t. If @p data is NULL no data
- * will be inserted into `result`. If @p data is already
- * in the packet buffer (e.g. a payload of an already
- * allocated packet) it will not be duplicated.
- * @param[in] size Length of @p data. If @p size is 0 no data will be inserted
- * into the the packet buffer and ng_pktsnip_t::data will be
- * set to @p data.
- * @param[in] type Protocol type of the ng_pktsnip_t.
+ * @param[in] pkt A received packet.
+ * @param[in] size The size of the new packet snip.
+ * @param[in] type The type of the new packet snip.
*
- * @return Pointer to the packet part that represents the new ng_pktsnip_t.
+ * @return The new packet snip in @p pkt on success.
+ * @return NULL, if pkt == NULL or size == 0 or size > pkt->size or pkt->data == NULL.
* @return NULL, if no space is left in the packet buffer.
- * @return NULL, if @p pkt != NULL, @p data = `pkt->data`,
- * and @p size > `pkt->data`.
*/
-ng_pktsnip_t *ng_pktbuf_add(ng_pktsnip_t *pkt, void *data, size_t size,
- ng_nettype_t type);
+ng_pktsnip_t *ng_pktbuf_mark(ng_pktsnip_t *pkt, size_t size, ng_nettype_t type);
/**
* @brief Reallocates ng_pktsnip_t::data of @p pkt in the packet buffer, without
* changing the content.
*
- * @pre `pkt->users == 1 && pkt->next == NULL` and @p pkt must be in packet buffer
+ * @pre ng_pktsnip_t::data of @p pkt is in the packet buffer.
*
* @details If enough memory is available behind it or @p size is smaller than
* the original size the packet then ng_pktsnip_t::data of @p pkt will
@@ -135,8 +125,6 @@ ng_pktsnip_t *ng_pktbuf_add(ng_pktsnip_t *pkt, void *data, size_t size,
* @param[in] size The size for @p pkt.
*
* @return 0, on success
- * @return EINVAL, if precondition is not met
- * @return ENOENT, if ng_pktsnip_t::data of @p pkt was not from the packet buffer.
* @return ENOMEM, if no space is left in the packet buffer or size was 0.
*/
int ng_pktbuf_realloc_data(ng_pktsnip_t *pkt, size_t size);
@@ -182,7 +170,7 @@ ng_pktsnip_t *ng_pktbuf_start_write(ng_pktsnip_t *pkt);
* @return The new reference to @p pkt.
*/
static inline ng_pktsnip_t *ng_pktbuf_remove_snip(ng_pktsnip_t *pkt,
- ng_pktsnip_t *snip)
+ ng_pktsnip_t *snip)
{
LL_DELETE(pkt, snip);
snip->next = NULL;
@@ -213,9 +201,12 @@ void ng_pktbuf_stats(void);
bool ng_pktbuf_is_empty(void);
/**
- * @brief Resets the whole packet buffer
+ * @brief Checks if the implenation's internal invariants still uphold
+ *
+ * @return true, the packet buffer is sane.
+ * @return false, the packet buffer is insane.
*/
-void ng_pktbuf_reset(void);
+bool ng_pktbuf_is_sane(void);
#endif
#ifdef __cplusplus