frag.h

Go to the documentation of this file.

/*
 * SPDX-FileCopyrightText: 2019 Freie Universität Berlin
 * SPDX-License-Identifier: LGPL-2.1-only
 */
 
#pragma once

 
#include <stdbool.h>
#include <stdint.h>
 
#include "byteorder.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define IPV6_EXT_FRAG_OFFSET_MASK   (0xFFF8)    
#define IPV6_EXT_FRAG_M             (0x0001)    

typedef struct __attribute__((packed)) {
    uint8_t nh;                     
    uint8_t resv;                   
    network_uint16_t offset_flags;
    network_uint32_t id;            
} ipv6_ext_frag_t;

static inline unsigned ipv6_ext_frag_get_offset(const ipv6_ext_frag_t *frag)
{
    /* The offset is left-shifted by 3 bytes in the header * (equivalent to
     * multiplication with 8), and the offset is in units 8 bytes
     * so no shifting or multiplying necessary to get offset in bytes */
    return (byteorder_ntohs(frag->offset_flags) & IPV6_EXT_FRAG_OFFSET_MASK);
}

static inline bool ipv6_ext_frag_more(const ipv6_ext_frag_t *frag)
{
    return (byteorder_ntohs(frag->offset_flags) & IPV6_EXT_FRAG_M);
}

static inline void ipv6_ext_frag_set_offset(ipv6_ext_frag_t *frag,
                                            unsigned offset)
{
    /* The offset is left-shifted by 3 bytes in the header * (equivalent to
     * multiplication with 8), and the offset is a multiple of 8 bytes
     * so no shifting or division necessary to set offset in units of 8 bytes */
    frag->offset_flags = byteorder_htons(offset & IPV6_EXT_FRAG_OFFSET_MASK);
}

static inline void ipv6_ext_frag_set_more(ipv6_ext_frag_t *frag)
{
    frag->offset_flags.u8[1] |= IPV6_EXT_FRAG_M;
}
 
#ifdef __cplusplus
}
#endif