/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 */
#ifndef __LWIP_INET_CHKSUM_H__
#define __LWIP_INET_CHKSUM_H__

#include "lwip/opt.h"

#include "lwip/pbuf.h"
#include "lwip/ip_addr.h"

/** Swap the bytes in an u16_t: much like htons() for little-endian */
#ifndef SWAP_BYTES_IN_WORD
#if LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN)
/* little endian and PLATFORM_BYTESWAP defined */
#define SWAP_BYTES_IN_WORD(w) LWIP_PLATFORM_HTONS(w)
#else /* LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN) */
/* can't use htons on big endian (or PLATFORM_BYTESWAP not defined)... */
#define SWAP_BYTES_IN_WORD(w) (((w) & 0xff) << 8) | (((w) & 0xff00) >> 8)
#endif /* LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN)*/
#endif /* SWAP_BYTES_IN_WORD */

/** Split an u32_t in two u16_ts and add them up */
#ifndef FOLD_U32T
#define FOLD_U32T(u)          (((u) >> 16) + ((u) & 0x0000ffffUL))
#endif

#if LWIP_CHECKSUM_ON_COPY
/** Function-like macro: same as MEMCPY but returns the checksum of copied data
    as u16_t */
#ifndef LWIP_CHKSUM_COPY
#define LWIP_CHKSUM_COPY(dst, src, len) lwip_chksum_copy(dst, src, len)
#ifndef LWIP_CHKSUM_COPY_ALGORITHM
#define LWIP_CHKSUM_COPY_ALGORITHM 1
#endif /* LWIP_CHKSUM_COPY_ALGORITHM */
#endif /* LWIP_CHKSUM_COPY */
#else /* LWIP_CHECKSUM_ON_COPY */
#define LWIP_CHKSUM_COPY_ALGORITHM 0
#endif /* LWIP_CHECKSUM_ON_COPY */

#ifdef __cplusplus
extern "C" {
#endif

u16_t inet_chksum(void *dataptr, u16_t len);
u16_t inet_chksum_pbuf(struct pbuf *p);
u16_t inet_chksum_pseudo(struct pbuf *p,
       ip_addr_t *src, ip_addr_t *dest,
       u8_t proto, u16_t proto_len);
u16_t inet_chksum_pseudo_partial(struct pbuf *p,
       ip_addr_t *src, ip_addr_t *dest,
       u8_t proto, u16_t proto_len, u16_t chksum_len);
#if LWIP_CHKSUM_COPY_ALGORITHM
u16_t lwip_chksum_copy(void *dst, const void *src, u16_t len);
#endif /* LWIP_CHKSUM_COPY_ALGORITHM */

#ifdef __cplusplus
}
#endif

#endif /* __LWIP_INET_H__ */