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RIOT/sys/include/net/gnrc/sixlowpan/frag.h

280 lines
8.8 KiB
C

/*
* Copyright (C) 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
* Copyright (C) 2015 Hamburg University of Applied Sciences
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @defgroup net_gnrc_sixlowpan_frag 6LoWPAN Fragmentation
* @ingroup net_gnrc_sixlowpan
* @brief 6LoWPAN Fragmentation headers and functionality
* @see <a href="https://tools.ietf.org/html/rfc4944#section-5.3">
* RFC 4944, section 5.3
* </a>
* @{
*
* @file
* @brief 6LoWPAN Fragmentation definitions
*
* @author Martine Lenders <mlenders@inf.fu-berlin.de>
* @author Peter Kietzmann <peter.kietzmann@haw-hamburg.de>
*/
#ifndef NET_GNRC_SIXLOWPAN_FRAG_H
#define NET_GNRC_SIXLOWPAN_FRAG_H
#include <inttypes.h>
#include <stdbool.h>
#include "byteorder.h"
#include "msg.h"
#include "net/gnrc/pkt.h"
#include "net/gnrc/netif/hdr.h"
#ifdef MODULE_GNRC_SIXLOWPAN_FRAG_HINT
#include "net/gnrc/sixlowpan/frag/hint.h"
#endif /* MODULE_GNRC_SIXLOWPAN_FRAG_HINT */
#include "net/gnrc/sixlowpan/internal.h"
#include "net/ieee802154.h"
#include "net/sixlowpan.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @name Message types
* @{
*/
/**
* @brief Message type for passing one 6LoWPAN fragment down the network stack
*/
#define GNRC_SIXLOWPAN_MSG_FRAG_SND (0x0225)
/**
* @brief Message type for triggering garbage collection reassembly buffer
*/
#define GNRC_SIXLOWPAN_MSG_FRAG_GC_RBUF (0x0226)
/** @} */
/**
* @brief Fragment intervals to identify limits of fragments and duplicates.
*
* @note Fragments MUST NOT overlap and overlapping fragments are to be
* discarded
*
* @see <a href="https://tools.ietf.org/html/rfc4944#section-5.3">
* RFC 4944, section 5.3
* </a>
*/
typedef struct gnrc_sixlowpan_rbuf_int {
/**
* @brief next element in fragment interval list
*/
struct gnrc_sixlowpan_rbuf_int *next;
uint16_t start; /**< start byte of the fragment interval */
uint16_t end; /**< end byte of the fragment interval */
} gnrc_sixlowpan_rbuf_int_t;
/**
* @brief Base class for both reassembly buffer and virtual reassembly buffer
*
* 1. the source address,
* 2. the destination address,
* 3. the datagram size, and
* 4. the datagram tag
*
* to identify all fragments that belong to the given datagram.
*
* @see [RFC 4944, section 5.3](https://tools.ietf.org/html/rfc4944#section-5.3)
* @see https://tools.ietf.org/html/draft-ietf-lwig-6lowpan-virtual-reassembly-01
*/
typedef struct {
gnrc_sixlowpan_rbuf_int_t *ints; /**< intervals of already received fragments */
uint8_t src[IEEE802154_LONG_ADDRESS_LEN]; /**< source address */
uint8_t dst[IEEE802154_LONG_ADDRESS_LEN]; /**< destination address */
uint8_t src_len; /**< length of gnrc_sixlowpan_rbuf_t::src */
uint8_t dst_len; /**< length of gnrc_sixlowpan_rbuf_t::dst */
uint16_t tag; /**< the datagram's tag */
uint16_t datagram_size; /**< the datagram's size */
/**
* @brief The number of bytes currently received of the complete datagram
*/
uint16_t current_size;
uint32_t arrival; /**< time in microseconds of arrival of
* last received fragment */
} gnrc_sixlowpan_rbuf_base_t;
/**
* @brief An entry in the 6LoWPAN reassembly buffer.
*
* A recipient of a fragment SHALL use
*
*/
typedef struct {
gnrc_sixlowpan_rbuf_base_t super; /**< base class */
/**
* @brief The reassembled packet in the packet buffer
*/
gnrc_pktsnip_t *pkt;
} gnrc_sixlowpan_rbuf_t;
/**
* @brief Definition of 6LoWPAN fragmentation type.
*/
typedef struct {
gnrc_pktsnip_t *pkt; /**< Pointer to the IPv6 packet to be fragmented */
uint16_t datagram_size; /**< Length of just the (uncompressed) IPv6 packet to be fragmented */
uint16_t tag; /**< Tag used for the fragment */
uint16_t offset; /**< Offset of the Nth fragment from the beginning of the
* payload datagram */
#ifdef MODULE_GNRC_SIXLOWPAN_FRAG_HINT
/**
* @brief Hint for the size (smaller than link-layer PDU) for the next
* fragment to sent
*/
gnrc_sixlowpan_frag_hint_t hint;
#endif /* MODULE_GNRC_SIXLOWPAN_FRAG_HINT */
} gnrc_sixlowpan_msg_frag_t;
#if defined(MODULE_GNRC_SIXLOWPAN_FRAG_STATS) || DOXYGEN
/**
* @brief Statistics on fragmentation and reassembly
*
* @note Only available with the `gnrc_sixlowpan_frag_stats` module
*/
typedef struct {
unsigned rbuf_full; /**< counts the number of events where the
* reassembly buffer is full */
unsigned frag_full; /**< counts the number of events that there where
* no @ref gnrc_sixlowpan_msg_frag_t available */
#if defined(MODULE_GNRC_SIXLOWPAN_FRAG_VRB) || DOXYGEN
unsigned vrb_full; /**< counts the number of events where the virtual
* reassembly buffer is full */
#endif
} gnrc_sixlowpan_frag_stats_t;
/**
* @brief Get the current statistics on fragmentation and reassembly
*
* @return The current statistics on fragmentation and reassembly
*/
gnrc_sixlowpan_frag_stats_t *gnrc_sixlowpan_frag_stats_get(void);
#endif
/**
* @brief Allocates a @ref gnrc_sixlowpan_msg_frag_t object
*
* @return A @ref gnrc_sixlowpan_msg_frag_t if available
* @return NULL, otherwise
*/
gnrc_sixlowpan_msg_frag_t *gnrc_sixlowpan_msg_frag_get(void);
/**
* @brief Sends a packet fragmented
*
* @pre `ctx != NULL`
* @pre gnrc_sixlowpan_msg_frag_t::pkt of @p ctx is equal to @p pkt or
* `pkt == NULL`.
*
* @param[in] pkt A packet. May be NULL.
* @param[in] ctx Message containing status of the 6LoWPAN fragmentation
* progress. Expected to be of type
* @ref gnrc_sixlowpan_msg_frag_t, with
* gnrc_sixlowpan_msg_frag_t set to @p pkt. Must not be
* NULL.
* @param[in] page Current 6Lo dispatch parsing page.
*/
void gnrc_sixlowpan_frag_send(gnrc_pktsnip_t *pkt, void *ctx, unsigned page);
/**
* @brief Handles a packet containing a fragment header
*
* @param[in] pkt The packet to handle
* @param[in] ctx Context for the packet. May be NULL.
* @param[in] page Current 6Lo dispatch parsing page.
*/
void gnrc_sixlowpan_frag_recv(gnrc_pktsnip_t *pkt, void *ctx, unsigned page);
/**
* @brief Generate a new datagram tag for sending
*
* @return A new datagram tag.
*/
uint16_t gnrc_sixlowpan_frag_next_tag(void);
/**
* @brief Remove base entry
*
* @param[in,out] entry Entry to remove
*/
void gnrc_sixlowpan_frag_rbuf_base_rm(gnrc_sixlowpan_rbuf_base_t *entry);
/**
* @brief Garbage collect reassembly buffer.
*/
void gnrc_sixlowpan_frag_rbuf_gc(void);
/**
* @brief Sends a message to pass a further fragment down the network stack
*
* @see GNRC_SIXLOWPAN_MSG_FRAG_SND
*
* @param[in] fragment_msg A @ref gnrc_sixlowpan_msg_frag_t object
*
* @return true, when the message was sent
* @return false when sending the message failed.
*/
static inline bool gnrc_sixlowpan_frag_send_msg(gnrc_sixlowpan_msg_frag_t *fragment_msg)
{
msg_t msg;
msg.content.ptr = fragment_msg;
msg.type = GNRC_SIXLOWPAN_MSG_FRAG_SND;
#ifdef TEST_SUITES
return (msg_try_send(&msg, gnrc_sixlowpan_get_pid()) > 0);
#else
return (msg_send_to_self(&msg) != 0);
#endif
}
#if defined(MODULE_GNRC_SIXLOWPAN_FRAG) || defined(DOXYGEN)
/**
* @brief Removes an entry from the reassembly buffer
*
* @pre `rbuf != NULL`
*
* @param[in] rbuf A reassembly buffer entry. Must not be NULL.
*/
void gnrc_sixlowpan_frag_rbuf_remove(gnrc_sixlowpan_rbuf_t *rbuf);
/**
* @brief Checks if a reassembly buffer entry is complete and dispatches it
* to the next layer if that is the case
*
* @pre `rbuf != NULL`
* @pre `netif != NULL`
*
* @param[in] rbuf A reassembly buffer entry. Must not be NULL.
* @param[in] netif Original @ref gnrc_netif_hdr_t of the last received frame.
* Used to construct the @ref gnrc_netif_hdr_t of the completed
* datagram. Must not be NULL.
*/
void gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(gnrc_sixlowpan_rbuf_t *rbuf,
gnrc_netif_hdr_t *netif);
#else
/* NOPs to be used with gnrc_sixlowpan_iphc if gnrc_sixlowpan_frag is not
* compiled in */
#define gnrc_sixlowpan_frag_rbuf_remove(rbuf) (void)(rbuf)
#define gnrc_sixlowpan_frag_rbuf_dispatch_when_complete(rbuf, netif) \
(void)(rbuf); (void)(netif)
#endif
#ifdef __cplusplus
}
#endif
#endif /* NET_GNRC_SIXLOWPAN_FRAG_H */
/** @} */