// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2022 Huawei Device Co., Ltd.
 *
 * Description: This file implements the function
 * of encapsulating the NewIP protocol header.
 *
 * Author: Yang Yanjun <yangyanjun@huawei.com>
 *
 * Data: 2022-07-18
 */
#include "nip_hdr.h"

#define INTEGER_MULTIPLE_OF_8 (~7) /* ~7 is an integer multiple of 8 */
#define FMT_FACTORY_NUM_MAX 1
#define ENCAP_FACTORY_NUM_MAX 1

void nip_calc_pkt_frag_num(unsigned int mtu,
			   unsigned int nip_hdr_len,
			   unsigned int usr_data_len,
			   struct nip_pkt_seg_info *seg_info)
{
	unsigned int mid_usr_pkt_len = (mtu - nip_hdr_len - NIP_UDP_HDR_LEN) &
				       INTEGER_MULTIPLE_OF_8;
	unsigned int mid_pkt_num = usr_data_len / mid_usr_pkt_len;
	unsigned int last_usr_pkt_len = 0;

	if (usr_data_len != 0) {
		last_usr_pkt_len = usr_data_len % mid_usr_pkt_len;
		if (last_usr_pkt_len == 0) {
			last_usr_pkt_len = mid_usr_pkt_len;
			mid_pkt_num--;
		}
	}

	seg_info->last_pkt_num = 1;
	seg_info->mid_pkt_num = mid_pkt_num;
	seg_info->mid_usr_pkt_len = mid_usr_pkt_len;
	seg_info->last_usr_pkt_len = last_usr_pkt_len;
}

static inline void _nip_hdr_ttl_encap(struct nip_hdr_encap *head)
{
	*(head->hdr_buf + head->hdr_buf_pos) = head->ttl;
	head->hdr_buf_pos += sizeof(head->ttl);
}

static inline void _nip_hdr_len_encap(struct nip_hdr_encap *head)
{
	head->hdr_len_pos = head->hdr_buf + head->hdr_buf_pos;
	head->hdr_buf_pos += 1;
}

static inline void _nip_update_hdr_len(struct nip_hdr_encap *head)
{
	*head->hdr_len_pos = head->hdr_buf_pos;
}

static inline void _nip_hdr_nexthdr_encap(struct nip_hdr_encap *head)
{
	*(head->hdr_buf + head->hdr_buf_pos) = head->nexthdr;
	head->hdr_buf_pos += sizeof(head->nexthdr);
}

static inline void _nip_hdr_daddr_encap(struct nip_hdr_encap *head)
{
	(void)build_nip_addr(&head->daddr, (head->hdr_buf + head->hdr_buf_pos));
	head->hdr_buf_pos += (head->daddr.bitlen / NIP_ADDR_BIT_LEN_8);
}

static inline void _nip_hdr_saddr_encap(struct nip_hdr_encap *head)
{
	(void)build_nip_addr(&head->saddr, (head->hdr_buf + head->hdr_buf_pos));
	head->hdr_buf_pos += (head->saddr.bitlen / NIP_ADDR_BIT_LEN_8);
}

static inline void _nip_hdr_total_len_encap(struct nip_hdr_encap *head)
{
	head->total_len_pos = (unsigned short *)(head->hdr_buf + head->hdr_buf_pos);
	head->hdr_buf_pos += sizeof(head->total_len);
}

/* total_len must be network order.(big end) */
void nip_update_total_len(struct nip_hdr_encap *head, unsigned short total_len)
{
	*head->total_len_pos = total_len;
}

#define BITMAP1_OFFSET 1
#define BITMAP2_OFFSET 2
static inline void _nip_hdr_encap_udp_bitmap(struct nip_hdr_encap *head)
{
	/* bitmap(1B) + ttl(1B) + total_len(2B) + nexthdr(1B) + daddr(xB) + saddr(xB) */
	/* If the length of the destination address and the source address is even,
	 * the length of the packet header must be odd. You need to add 1-byte alignment
	 * and 1-byte bitmap
	 */
	if (((head->daddr.bitlen / NIP_ADDR_BIT_LEN_8) + (head->saddr.bitlen / NIP_ADDR_BIT_LEN_8))
	    % NIP_BYTE_ALIGNMENT != 0) {
		head->hdr_buf[0] = NIP_UDP_BITMAP_1;
		head->hdr_buf_pos = BITMAP1_OFFSET;
	} else {
		head->hdr_buf[0] = NIP_UDP_BITMAP_1_INC_2;
		head->hdr_buf[1] = NIP_NODATA_BITMAP_2;
		head->hdr_buf_pos = BITMAP2_OFFSET;
	}
}

static inline void _nip_hdr_encap_comm_bitmap(struct nip_hdr_encap *head)
{
	/* bitmap(1B) + ttl(1B) + nexthdr(1B) + daddr(xB) + saddr(xB) */
	/* If the length of the destination address and the source address is even,
	 * the length of the packet header must be odd. You need to add 1-byte alignment
	 * and 1-byte bitmap
	 */
	if (((head->daddr.bitlen / NIP_ADDR_BIT_LEN_8) + (head->saddr.bitlen / NIP_ADDR_BIT_LEN_8))
	    % NIP_BYTE_ALIGNMENT != 0) {
		head->hdr_buf[0] = NIP_NORMAL_BITMAP_1;
		head->hdr_buf_pos = BITMAP1_OFFSET;
	} else {
		head->hdr_buf[0] = NIP_NORMAL_BITMAP_1_INC_2;
		head->hdr_buf[1] = NIP_NODATA_BITMAP_2;
		head->hdr_buf_pos = BITMAP2_OFFSET;
	}
}

#define NEWIP_BYTE_ALIGNMENT_ENABLE 1 // 0: disable; 1: enable

void nip_hdr_udp_encap(struct nip_hdr_encap *head)
{
	int len;

	if (!head)
		return;

	len = get_nip_hdr_len(NIP_HDR_UDP, &head->saddr, &head->daddr);
	if (len == 0 || len > NIP_HDR_MAX)
		return;

	/* Encapsulate the bitmap into the newIP packet header BUF */
#if (NEWIP_BYTE_ALIGNMENT_ENABLE == 1)
	_nip_hdr_encap_udp_bitmap(head);
#else
	head->hdr_buf[0] = NIP_UDP_BITMAP_1;
	head->hdr_buf_pos = 1;
#endif

	/* Encapsulate bitmap fields into newIP packet header BUF */
	_nip_hdr_ttl_encap(head);
	_nip_hdr_nexthdr_encap(head);
	_nip_hdr_daddr_encap(head);
	_nip_hdr_saddr_encap(head);
}

/* need update total len after this func, call nip_update_total_len */
void nip_hdr_comm_encap(struct nip_hdr_encap *head)
{
	int len;

	if (!head)
		return;

	len = get_nip_hdr_len(NIP_HDR_COMM, &head->saddr, &head->daddr);
	if (len == 0 || len > NIP_HDR_MAX)
		return;

	/* Encapsulate the bitmap into the newIP packet header BUF */
#if (NEWIP_BYTE_ALIGNMENT_ENABLE == 1)
	_nip_hdr_encap_comm_bitmap(head);
#else
	head->hdr_buf[0] = NIP_NORMAL_BITMAP_1;
	head->hdr_buf_pos = 1;
#endif

	/* Encapsulate bitmap fields into newIP packet header BUF */
	_nip_hdr_ttl_encap(head);
	_nip_hdr_total_len_encap(head); /* ARP/TCP need include hdr total len */
	_nip_hdr_nexthdr_encap(head);
	_nip_hdr_daddr_encap(head);
	_nip_hdr_saddr_encap(head);
}

#if (NEWIP_BYTE_ALIGNMENT_ENABLE == 1)    // include bitmap2
#define NIP_COMM_HDR_LEN_NOINCLUDE_ADDR 6 // include total len
#define NIP_UDP_HDR_LEN_NOINCLUDE_ADDR  4 // not include total len
#else
#define NIP_COMM_HDR_LEN_NOINCLUDE_ADDR 5 // include total len
#define NIP_UDP_HDR_LEN_NOINCLUDE_ADDR  3 // not include total len
#endif
/* bitmap1 + bitmap2 + TTL + total len + nexthd + daddr + saddr
 * 1B        1B        1B    2B          1B       7B      7B    = 20B
 * NIP_HDR_MAX 20
 * V4  TCP 1448
 * NIP TCP 1430 + 30 = 1460
 */
/* The length of the packet header is obtained according to the packet type,
 * source ADDRESS, and destination address.
 * If the packet does not carry the source address or destination address, fill in the blank
 */
int get_nip_hdr_len(enum NIP_HDR_TYPE hdr_type,
		    const struct nip_addr *saddr,
		    const struct nip_addr *daddr)
{
	int saddr_len = 0;
	int daddr_len = 0;
	enum NIP_HDR_TYPE base_len = hdr_type == NIP_HDR_UDP ?
				     NIP_UDP_HDR_LEN_NOINCLUDE_ADDR :
				     NIP_COMM_HDR_LEN_NOINCLUDE_ADDR;

	if (hdr_type >= NIP_HDR_TYPE_MAX)
		return 0;

	if (saddr) {
		saddr_len = get_nip_addr_len(saddr);
		if (saddr_len == 0)
			return 0;
	}

	if (daddr) {
		daddr_len = get_nip_addr_len(daddr);
		if (daddr_len == 0)
			return 0;
	}

	return base_len + saddr_len + daddr_len;
}