1
0
mirror of https://github.com/RIOT-OS/RIOT.git synced 2024-12-29 04:50:03 +01:00
RIOT/sys/include/net/ng_pkt.h
2015-02-11 11:01:33 +01:00

114 lines
4.3 KiB
C

/*
* Copyright (C) 2014, 2015 Martine Lenders <mlenders@inf.fu-berlin.de>
*
* 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 ng_pkt Packet
* @brief Network packet abstraction types
* @ingroup net
* @{
*
* @file
* @brief General definitions for network packets
*
* @author Martine Lenders <mlenders@inf.fu-berlin.de>
*/
#ifndef NG_PKT_H_
#define NG_PKT_H_
#include <inttypes.h>
#include <stdlib.h>
#include "net/ng_nettype.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Type to represent snips (or parts,
* snip == (packet header || packet payload)) of a network packet
* @details The idea behind the packet snips is that they either can represent
* protocol-specific headers or payload. A packet can be comprised of
* *n* `pktsnip_t` elements, where the first element represents the
* header of the lowest available network layer and the *(n - 1)*st
* element represents the payload of the highest available layer.
* Use @ref sys_ut to operate on this.
*
* Example:
*
* buffer
* +---------------------------+ +------+
* | size = 14 | data +-------------->| |
* | type = PKT_PROTO_ETHERNET |------+ +------+
* +---------------------------+ +----------->| |
* | next | | |
* v | | |
* +---------------------------+ | +------+
* | size = 40 | data | +-------->| |
* | type = PKT_PROTO_IPV6 |---------+ | +------+
* +---------------------------+ | +----->| |
* | next | | +------+
* v | | +-->| |
* +---------------------------+ | | | | |
* | size = 8 | data | | | . .
* | type = PKT_PROTO_UDP |------------+ | | . .
* +---------------------------+ | |
* | next | |
* v | |
* +---------------------------+ | |
* | size = 5 | data | |
* | type = PKT_PROTO_COAP |---------------+ |
* +---------------------------+ |
* | next |
* v |
* +---------------------------+ |
* | size = 54 | data |
* | type = PKT_PROTO_UNKNOWN |------------------+
* +---------------------------+
*
*
* @note This type implements its own list implementation because of the way
* it is stored in the packet buffer.
* @note This type has no initializer on purpose. Please use @ref pktbuf
* as factory.
*/
typedef struct __attribute__((packed)) ng_pktsnip { /* packed to be aligned
* correctly in the static
* packet buffer */
struct ng_pktsnip *next; /**< next snip in the packet */
void *data; /**< pointer to the data of the snip */
size_t size; /**< the length of the snip in byte */
ng_nettype_t type; /**< protocol of the packet snip */
} ng_pktsnip_t;
/**
* @brief Calculates length of a packet in byte.
*
* @param[in] pkt list of packet snips.
*
* @return length of the list of headers.
*/
static inline size_t ng_pkt_len(ng_pktsnip_t *pkt)
{
size_t len = 0;
while (pkt) {
len += pkt->size;
pkt = pkt->next;
}
return len;
}
#ifdef __cplusplus
}
#endif
#endif /* NG_PKT_H_ */
/** @} */