#ifndef _VXLAN_H
#define _VXLAN_H

#ifdef __cpluscplus
extern "C"
{
#endif

#define __FAVOR_BSD 1
#include <netinet/udp.h>

#include "tuple.h"

/*
 ******************************************************************************
 * Standard VXLAN Header:
 ******************************************************************************
 *
 *   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
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |R|R|R|R|I|R|R|R|            Reserved                           |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                VXLAN Network Identifier (VNI) |   Reserved    |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * Flags (8 bits):
 *       where the I flag MUST be set to 1 for a valid VXLAN Network ID (VNI).
 *       The other 7 bits (designated "R") are reserved fields and MUST be set
 *       to zero on transmission and ignored on receipt.
 * Reserved fields (24 bits and 8 bits):
 *       MUST be set to zero on transmission and ignored on receipt.
 *
 ******************************************************************************
 * SCE VXLAN Header:
 ******************************************************************************
 *
 *   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
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |R|R|R|R|I|R|R|R| Reserved    |S|    Traffic Link ID            |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |      high     | type  | low   |D|T|SF index |T|   Reserved    |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * 		Flags              :  8 bits
 * 		Reserved           :  7 bits
 * 		S (StateLess)      :  1 bit
 *
 * 		Traffic Link ID    : 16 bits
 *
 * 		vlan_id_half_high  :  8 bits
 * 		link_layer_type    :  4 bits // 二层报文封装格式
 * 		vlan_id_half_low   :  4 bits
 *
 * 		dir                :  1 bit
 * 		traffic            :  1 bit
 * 		sf_index           :  5 bits // max value 32
 * 		online_test        :  1 bit
 *
 * 		Reserved           :  8 bit
 */

struct vxlan_hdr
{
	uint16_t flags_reserved;
	uint16_t link_id;
	uint16_t vlan_id;
	uint16_t user_ctx;
} __attribute__((__packed__));

#define VXLAN_DEFAULT_FLAGS 0x8
#define VXLAN_DST_PORT 4789
#define VXLAN_FRAME_HDR_LEN ((int)(sizeof(struct ethhdr) + sizeof(struct ip) + sizeof(struct udphdr) + sizeof(struct vxlan_hdr)))

#define VXLAN_FLAGS_MASK 0xFF00
#define VXLAN_STATELESS_MASK 0x0001
#define VXLAN_DIR_MASK 0x8000
#define VXLAN_TRAFFIC_MASK 0x4000
#define VXLAN_SF_INDEX_MASK 0x3E00

static inline void vxlan_set_flags(struct vxlan_hdr *hdr, uint8_t flags)
{
	hdr->flags_reserved = htons((ntohs(hdr->flags_reserved) & ~VXLAN_FLAGS_MASK) | (flags << 8));
}

static inline void vxlan_set_dir(struct vxlan_hdr *hdr, uint8_t val)
{
	hdr->user_ctx = htons((ntohs(hdr->user_ctx) & ~VXLAN_DIR_MASK) | ((!!val) << 15));
}

static inline void vxlan_set_traffic(struct vxlan_hdr *hdr, uint8_t val)
{
	hdr->user_ctx = htons((ntohs(hdr->user_ctx) & ~VXLAN_TRAFFIC_MASK) | ((!!val) << 14));
}

static inline void vxlan_set_sf_index(struct vxlan_hdr *hdr, uint8_t val)
{
	hdr->user_ctx = htons((ntohs(hdr->user_ctx) & ~VXLAN_SF_INDEX_MASK) | ((val & 0x1F) << 9));
}

static inline void vxlan_set_link_id(struct vxlan_hdr *hdr, uint16_t val)
{
	hdr->link_id = htons(val);
}

static inline void vxlan_set_stateless(struct vxlan_hdr *hdr, uint8_t val)
{
	hdr->flags_reserved = htons((ntohs(hdr->flags_reserved) & ~VXLAN_STATELESS_MASK) | (!!val));
}

static inline uint8_t vxlan_get_flags(struct vxlan_hdr *hdr)
{
	return ((ntohs(hdr->flags_reserved) & VXLAN_FLAGS_MASK) >> 8);
}

static inline uint8_t vxlan_get_dir(struct vxlan_hdr *hdr)
{
	return ((ntohs(hdr->user_ctx) & VXLAN_DIR_MASK) >> 15);
}

static inline uint8_t vxlan_get_traffic(struct vxlan_hdr *hdr)
{
	return ((ntohs(hdr->user_ctx) & VXLAN_TRAFFIC_MASK) >> 14);
}

static inline uint8_t vxlan_get_sf_index(struct vxlan_hdr *hdr)
{
	return ((ntohs(hdr->user_ctx) & VXLAN_SF_INDEX_MASK) >> 9);
}

static inline uint16_t vxlan_get_link_id(struct vxlan_hdr *hdr)
{
	return ntohs(hdr->link_id);
}

static inline uint8_t vxlan_get_stateless(struct vxlan_hdr *hdr)
{
	return ntohs(hdr->flags_reserved) & VXLAN_STATELESS_MASK;
}

// return  0 : success
// return -1 : error
int vxlan_frame_decode(struct vxlan_hdr **vxlan_hdr, const char *data, int len);
void vxlan_frame_encode(char *buff,
						const u_char eth_src_mac[], const u_char eth_dst_mac[],
						const in_addr_t ip_src_addr, const in_addr_t ip_dst_addr, uint16_t ip_id,
						uint16_t udp_src_port, uint16_t udp_pld_len,
						uint8_t dir, uint8_t traffic, uint8_t sf_index, uint16_t link_id);

uint16_t calculate_vxlan_source_port(struct four_tuple *innermost_tuple4);

#ifdef __cpluscplus
}
#endif

#endif