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/*

 * 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>

 *

 */

/* inet.c

 *

 * Functions common to all TCP/IP modules, such as the Internet checksum and the

 * byte order functions.

 *

 */

#include "lwip/opt.h"

#include "lwip/arch.h"

#include "lwip/def.h"

#include "lwip/inet.h"

#include "lwip/sys.h"

/* These are some reference implementations of the checksum algorithm, with the

 * aim of being simple, correct and fully portable. Checksumming is the

 * first thing you would want to optimize for your platform. If you create

 * your own version, link it in and in your sys_arch.h put:

 *

 * #define LWIP_CHKSUM <your_checksum_routine>

*/

#ifndef LWIP_CHKSUM

#define LWIP_CHKSUM lwip_standard_chksum

#if 1 /* Version A */

/**

 * lwip checksum

 *

 * @param dataptr points to start of data to be summed at any boundary

 * @param len length of data to be summed

 * @return host order (!) lwip checksum (non-inverted Internet sum)

 *

 * @note accumulator size limits summable length to 64k

 * @note host endianess is irrelevant (p3 RFC1071)

 */

static u16_t

lwip_standard_chksum(void *dataptr, u16_t len)

{

  u32_t acc;

  u16_t src;

  u8_t *octetptr;

  acc = 0;

  /* dataptr may be at odd or even addresses */

  octetptr = (u8_t*)dataptr;

  while (len > 1)

  {

    /* declare first octet as most significant

       thus assume network order, ignoring host order */

    src = (*octetptr) << 8;

    octetptr++;

    /* declare second octet as least significant */

    src |= (*octetptr);

    octetptr++;

    acc += src;

    len -= 2;

  }

  if (len > 0)

  {

    /* accumulate remaining octet */

    src = (*octetptr) << 8;

    acc += src;

  }

  /* add deferred carry bits */

  acc = (acc >> 16) + (acc & 0x0000ffffUL);

  if ((acc & 0xffff0000) != 0) {

    acc = (acc >> 16) + (acc & 0x0000ffffUL);

  }

  /* This maybe a little confusing: reorder sum using htons()

     instead of ntohs() since it has a little less call overhead.

     The caller must invert bits for Internet sum ! */

  return htons((u16_t)acc);

}

#endif

#if 0 /* Version B */

/*

 * Curt McDowell

 * Broadcom Corp.

 * csm@broadcom.com

 *

 * IP checksum two bytes at a time with support for

 * unaligned buffer.

 * Works for len up to and including 0x20000.

 * by Curt McDowell, Broadcom Corp. 12/08/2005

 */

static u16_t

lwip_standard_chksum(void *dataptr, int len)

{

  u8_t *pb = dataptr;

  u16_t *ps, t = 0;

  u32_t sum = 0;

  int odd = ((u32_t)pb & 1);

  /* Get aligned to u16_t */

  if (odd && len > 0) {

    ((u8_t *)&t)[1] = *pb++;

    len--;

  }

  /* Add the bulk of the data */

  ps = (u16_t *)pb;

  while (len > 1) {

    sum += *ps++;

    len -= 2;

  }

  /* Consume left-over byte, if any */

  if (len > 0)

    ((u8_t *)&t)[0] = *(u8_t *)ps;;

  /* Add end bytes */

  sum += t;

  /*  Fold 32-bit sum to 16 bits */

  while (sum >> 16)

    sum = (sum & 0xffff) + (sum >> 16);

  /* Swap if alignment was odd */

  if (odd)

    sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);

  return sum;

}

#endif

#if 0 /* Version C */

/**

 * An optimized checksum routine. Basically, it uses loop-unrolling on

 * the checksum loop, treating the head and tail bytes specially, whereas

 * the inner loop acts on 8 bytes at a time.

 *

 * @arg start of buffer to be checksummed. May be an odd byte address.

 * @len number of bytes in the buffer to be checksummed.

 *

 * by Curt McDowell, Broadcom Corp. December 8th, 2005

 */

static u16_t

lwip_standard_chksum(void *dataptr, int len)

{

  u8_t *pb = dataptr;

  u16_t *ps, t = 0;

  u32_t *pl;

  u32_t sum = 0, tmp;

  /* starts at odd byte address? */

  int odd = ((u32_t)pb & 1);

  if (odd && len > 0) {

    ((u8_t *)&t)[1] = *pb++;

    len--;

  }

  ps = (u16_t *)pb;

  if (((u32_t)ps & 3) && len > 1) {

    sum += *ps++;

    len -= 2;

  }

  pl = (u32_t *)ps;

  while (len > 7)  {

    tmp = sum + *pl++;          /* ping */

    if (tmp < sum)

      tmp++;                    /* add back carry */

    sum = tmp + *pl++;          /* pong */

    if (sum < tmp)

      sum++;                    /* add back carry */

    len -= 8;

  }

  /* make room in upper bits */

  sum = (sum >> 16) + (sum & 0xffff);

  ps = (u16_t *)pl;

  /* 16-bit aligned word remaining? */

  while (len > 1) {

    sum += *ps++;

    len -= 2;

  }

  /* dangling tail byte remaining? */

  if (len > 0)                  /* include odd byte */

    ((u8_t *)&t)[0] = *(u8_t *)ps;

  sum += t;                     /* add end bytes */

  while (sum >> 16)             /* combine halves */

    sum = (sum >> 16) + (sum & 0xffff);

  if (odd)

    sum = ((sum & 0xff) << 8) | ((sum & 0xff00) >> 8);

  return sum;

}

#endif

#endif /* LWIP_CHKSUM */

/* inet_chksum_pseudo:

 *

 * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.

 */

u16_t

inet_chksum_pseudo(struct pbuf *p,

       struct ip_addr *src, struct ip_addr *dest,

       u8_t proto, u16_t proto_len)

{

  u32_t acc;

  struct pbuf *q;

  u8_t swapped;

  acc = 0;

  swapped = 0;

  /* iterate through all pbuf in chain */

  for(q = p; q != NULL; q = q->next) {

    LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): checksumming pbuf %p (has next %p) \n",

      (void *)q, (void *)q->next));

    acc += LWIP_CHKSUM(q->payload, q->len);

    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): unwrapped lwip_chksum()=%"X32_F" \n", acc));*/

    while (acc >> 16) {

      acc = (acc & 0xffffUL) + (acc >> 16);

    }

    if (q->len % 2 != 0) {

      swapped = 1 - swapped;

      acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);

    }

    /*LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): wrapped lwip_chksum()=%"X32_F" \n", acc));*/

  }

  if (swapped) {

    acc = ((acc & 0xff) << 8) | ((acc & 0xff00UL) >> 8);

  }

  acc += (src->addr & 0xffffUL);

  acc += ((src->addr >> 16) & 0xffffUL);

  acc += (dest->addr & 0xffffUL);

  acc += ((dest->addr >> 16) & 0xffffUL);

  acc += (u32_t)htons((u16_t)proto);

  acc += (u32_t)htons(proto_len);

  while (acc >> 16) {

    acc = (acc & 0xffffUL) + (acc >> 16);

  }

  LWIP_DEBUGF(INET_DEBUG, ("inet_chksum_pseudo(): pbuf chain lwip_chksum()=%"X32_F"\n", acc));

  return (u16_t)~(acc & 0xffffUL);

}

/* inet_chksum:

 *

 * Calculates the Internet checksum over a portion of memory. Used primarily for IP

 * and ICMP.

 */

u16_t

inet_chksum(void *dataptr, u16_t len)

{

  u32_t acc;

  acc = LWIP_CHKSUM(dataptr, len);

  while (acc >> 16) {

    acc = (acc & 0xffff) + (acc >> 16);

  }

  return (u16_t)~(acc & 0xffff);

}

u16_t

inet_chksum_pbuf(struct pbuf *p)

{

  u32_t acc;

  struct pbuf *q;

  u8_t swapped;

  acc = 0;

  swapped = 0;

  for(q = p; q != NULL; q = q->next) {

    acc += LWIP_CHKSUM(q->payload, q->len);

    while (acc >> 16) {

      acc = (acc & 0xffffUL) + (acc >> 16);

    }

    if (q->len % 2 != 0) {

      swapped = 1 - swapped;

      acc = (acc & 0x00ffUL << 8) | (acc & 0xff00UL >> 8);

    }

  }

  if (swapped) {

    acc = ((acc & 0x00ffUL) << 8) | ((acc & 0xff00UL) >> 8);

  }

  return (u16_t)~(acc & 0xffffUL);

}

/* Here for now until needed in other places in lwIP */

#ifndef isprint

#define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)

#define isprint(c)           in_range(c, 0x20, 0x7f)

#define isdigit(c)           in_range(c, '0', '9')

#define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))

#define islower(c)           in_range(c, 'a', 'z')

#define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')

#endif    

/*

 * Ascii internet address interpretation routine.

 * The value returned is in network order.

 */

u32_t

inet_addr(const char *cp)

{

  struct in_addr val;

  if (inet_aton(cp, &val)) {

    return (val.s_addr);

  }

  return (INADDR_NONE);

}

/*

 * Check whether "cp" is a valid ascii representation

 * of an Internet address and convert to a binary address.

 * Returns 1 if the address is valid, 0 if not.

 * This replaces inet_addr, the return value from which

 * cannot distinguish between failure and a local broadcast address.

 */

int

inet_aton(const char *cp, struct in_addr *addr)

{

  u32_t val;

  int base, n, c;

  u32_t parts[4];

  u32_t *pp = parts;

  c = *cp;

  for (;;) {

    /*

     * Collect number up to ``.''.

     * Values are specified as for C:

     * 0x=hex, 0=octal, 1-9=decimal.

     */

    if (!isdigit(c))

      return (0);

    val = 0;

    base = 10;

    if (c == '0') {

      c = *++cp;

      if (c == 'x' || c == 'X') {

        base = 16;

        c = *++cp;

      } else

        base = 8;

    }

    for (;;) {

      if (isdigit(c)) {

        val = (val * base) + (int)(c - '0');

        c = *++cp;

      } else if (base == 16 && isxdigit(c)) {

        val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));

        c = *++cp;

      } else

        break;

    }

    if (c == '.') {

      /*

       * Internet format:

       *  a.b.c.d

       *  a.b.c   (with c treated as 16 bits)

       *  a.b (with b treated as 24 bits)

       */

      if (pp >= parts + 3)

        return (0);

      *pp++ = val;

      c = *++cp;

    } else

      break;

  }

  /*

   * Check for trailing characters.

   */

  if (c != '\0' && (!isprint(c) || !isspace(c)))

    return (0);

  /*

   * Concoct the address according to

   * the number of parts specified.

   */

  n = pp - parts + 1;

  switch (n) {

  case 0:

    return (0);       /* initial nondigit */

  case 1:             /* a -- 32 bits */

    break;

  case 2:             /* a.b -- 8.24 bits */

    if (val > 0xffffff)

      return (0);

    val |= parts[0] << 24;

    break;

  case 3:             /* a.b.c -- 8.8.16 bits */

    if (val > 0xffff)

      return (0);

    val |= (parts[0] << 24) | (parts[1] << 16);

    break;

  case 4:             /* a.b.c.d -- 8.8.8.8 bits */

    if (val > 0xff)

      return (0);

    val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);

    break;

  }

  if (addr)

    addr->s_addr = htonl(val);

  return (1);

}

/* Convert numeric IP address into decimal dotted ASCII representation.

 * returns ptr to static buffer; not reentrant!

 */

char *

inet_ntoa(struct in_addr addr)

{

  static char str[16];

  u32_t s_addr = addr.s_addr;

  char inv[3];

  char *rp;

  u8_t *ap;

  u8_t rem;

  u8_t n;

  u8_t i;

  rp = str;

  ap = (u8_t *)&s_addr;

  for(n = 0; n < 4; n++) {

    i = 0;

    do {

      rem = *ap % (u8_t)10;

      *ap /= (u8_t)10;

      inv[i++] = '0' + rem;

    } while(*ap);

    while(i--)

      *rp++ = inv[i];

    *rp++ = '.';

    ap++;

  }

  *--rp = 0;

  return str;

}

/*

 * These are reference implementations of the byte swapping functions.

 * Again with the aim of being simple, correct and fully portable.

 * Byte swapping is the second thing you would want to optimize. You will

 * need to port it to your architecture and in your cc.h:

 *

 * #define LWIP_PLATFORM_BYTESWAP 1

 * #define LWIP_PLATFORM_HTONS(x) <your_htons>

 * #define LWIP_PLATFORM_HTONL(x) <your_htonl>

 *

 * Note ntohs() and ntohl() are merely references to the htonx counterparts.

 */

#ifndef BYTE_ORDER

#error BYTE_ORDER is not defined

#endif

#if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)

u16_t

htons(u16_t n)

{

  return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);

}

u16_t

ntohs(u16_t n)

{

  return htons(n);

}

u32_t

htonl(u32_t n)

{

  return ((n & 0xff) << 24) |

    ((n & 0xff00) << 8) |

    ((n & 0xff0000) >> 8) |

    ((n & 0xff000000) >> 24);

}

u32_t

ntohl(u32_t n)

{

  return htonl(n);

}

#endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */