pkt.h

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/*
 * SPDX-FileCopyrightText: 2014-2015 Martine Lenders <mlenders@inf.fu-berlin.de>
 * SPDX-FileCopyrightText: 2015 Freie Universität Berlin
 * SPDX-License-Identifier: LGPL-2.1-only
 */
 
#pragma once

 
#include <inttypes.h>
#include <stdlib.h>
 
#include "sched.h"
#include "net/gnrc/nettype.h"
#include "list.h"
 
#ifdef __cplusplus
extern "C" {
#endif

/* packed to be aligned correctly in the static packet buffer */
typedef struct gnrc_pktsnip {
    /* the first three fields *MUST* match iolist_t! */
    struct gnrc_pktsnip *next;      
    void *data;                     
    size_t size;                    
    /* end of iolist_t */
#ifdef MODULE_GNRC_NETERR
    kernel_pid_t err_sub;           
#endif
    gnrc_nettype_t type;            
    uint8_t users;
} gnrc_pktsnip_t;

static inline gnrc_pktsnip_t *gnrc_pkt_prev_snip(gnrc_pktsnip_t *pkt,
                                                 gnrc_pktsnip_t *snip)
{
    while ((pkt != NULL) && (pkt->next != snip)) {
        pkt = pkt->next;
    }
    return pkt;
}

static inline size_t gnrc_pkt_len(const gnrc_pktsnip_t *pkt)
{
    size_t len = 0;
 
    while (pkt != NULL) {
        len += pkt->size;
        pkt = pkt->next;
    }
 
    return len;
}

static inline gnrc_pktsnip_t *gnrc_pkt_append(gnrc_pktsnip_t *pkt,
                                              gnrc_pktsnip_t *snip)
{
    /* find last snip in pkt */
    gnrc_pktsnip_t *last = gnrc_pkt_prev_snip(pkt, NULL);
 
    if (last != NULL) {
        last->next = snip;
    }
    else {
        /* last == NULL means snip */
        pkt = snip;
    }
    return pkt;
}

static inline gnrc_pktsnip_t *gnrc_pkt_prepend(gnrc_pktsnip_t *pkt,
                                               gnrc_pktsnip_t *snip)
{
    snip->next = pkt;
    return snip;
}

static inline gnrc_pktsnip_t *gnrc_pkt_delete(gnrc_pktsnip_t *pkt,
                                              gnrc_pktsnip_t *snip)
{
    /* Removing head is a no-op. The new head is the next in the list. */
    if (pkt == snip) {
        return pkt->next;
    }
 
    /* Removing nothing is a no-op, the new head is the old one */
    if (snip == NULL) {
        return pkt;
    }
 
    /* Iterate over the list and remove the given snip from it, if found.
     * The new head is the old head. */
    for (gnrc_pktsnip_t *i = pkt; i != NULL; i = i->next) {
        if (i->next == snip) {
            i->next = snip->next;
            return pkt;
        }
    }
 
    return pkt;
}

static inline size_t gnrc_pkt_len_upto(const gnrc_pktsnip_t *pkt, gnrc_nettype_t type)
{
    size_t len = 0;
 
    while (pkt != NULL) {
        len += pkt->size;
 
        if (pkt->type == type) {
            break;
        }
 
        pkt = pkt->next;
    }
 
    return len;
}

static inline size_t gnrc_pkt_count(const gnrc_pktsnip_t *pkt)
{
    size_t count = 0;
 
    while (pkt != NULL) {
        ++count;
        pkt = pkt->next;
    }
 
    return count;
}

gnrc_pktsnip_t *gnrc_pktsnip_search_type(gnrc_pktsnip_t *pkt,
                                         gnrc_nettype_t type);
 
#ifdef __cplusplus
}
#endif