#ifndef _VLAN_UTILS_H
#define _VLAN_UTILS_H

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include "eth_utils.h"

/*
 * VLAN Header Format
 *
 *   0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  | Pri |I|    VLAN ID            |           Ethertype           |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct vlan_hdr
{
    uint16_t vlan_tci;
    uint16_t vlan_ethertype;
};

/******************************************************************************
 * get
 ******************************************************************************/

static inline uint8_t vlan_hdr_get_priority(const struct vlan_hdr *hdr)
{
    return (ntohs(hdr->vlan_tci) & 0xe000) >> 13;
}

static inline uint8_t vlan_hdr_get_dei(const struct vlan_hdr *hdr)
{
    return (ntohs(hdr->vlan_tci) & 0x1000) >> 12;
}

static inline uint16_t vlan_hdr_get_vid(const struct vlan_hdr *hdr)
{
    return ntohs(hdr->vlan_tci) & 0x0fff;
}

static inline uint16_t vlan_hdr_get_ethertype(const struct vlan_hdr *hdr)
{
    return ntohs(hdr->vlan_ethertype);
}

/******************************************************************************
 * set
 ******************************************************************************/

static inline void vlan_hdr_set_priority(struct vlan_hdr *hdr, uint8_t priority)
{
    hdr->vlan_tci = htons((ntohs(hdr->vlan_tci) & ~0xe000) | (priority << 13));
}

static inline void vlan_hdr_set_dei(struct vlan_hdr *hdr, uint8_t dei)
{
    hdr->vlan_tci = htons((ntohs(hdr->vlan_tci) & ~0x1000) | (dei << 12));
}

static inline void vlan_hdr_set_vid(struct vlan_hdr *hdr, uint16_t vid)
{
    hdr->vlan_tci = htons((ntohs(hdr->vlan_tci) & ~0x0fff) | vid);
}

static inline void vlan_hdr_set_ethertype(struct vlan_hdr *hdr, uint16_t ethertype)
{
    hdr->vlan_ethertype = htons(ethertype);
}

/******************************************************************************
 * print
 ******************************************************************************/

static inline int vlan_hdr_to_str(const struct vlan_hdr *hdr, char *buf, size_t size)
{
    memset(buf, 0, size);
    uint16_t proto = vlan_hdr_get_ethertype(hdr);
    return snprintf(buf, size, "VLAN: priority=%u dei=%u id=%u ethertype=%s",
                    vlan_hdr_get_priority(hdr), vlan_hdr_get_dei(hdr),
                    vlan_hdr_get_vid(hdr), eth_proto_to_str(proto));
}

#ifdef __cplusplus
}
#endif

#endif