inet.c

/**
 * @file
 * Functions common to all TCP/IPv4 modules, such as the byte order functions.
 *
 */

/*
 * 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>
 *
 */

#include "lwip/opt.h"

#include "lwip/inet.h"

/* 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.
 *
 * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
 * @return ip address 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.
 *
 * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
 * @param addr pointer to which to save the ip address in network order
 * @return 1 if cp could be converted to addr, 0 on failure
 */
int
inet_aton(const char *cp, struct in_addr *addr)
{
  u32_t val;
  u8_t base;
  char 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' && !isspace(c))
    return (0);
  /*
   * Concoct the address according to
   * the number of parts specified.
   */
  switch (pp - parts + 1) {

  case 0:
    return (0);       /* initial nondigit */

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

  case 2:             /* a.b -- 8.24 bits */
    if (val > 0xffffffUL)
      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!
 *
 * @param addr ip address in network order to convert
 * @return pointer to a global static (!) buffer that holds the ASCII
 *         represenation of addr
 */
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.
 */

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

/**
 * Convert an u16_t from host- to network byte order.
 *
 * @param n u16_t in host byte order
 * @return n in network byte order
 */
u16_t
htons(u16_t n)
{
  return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
}

/**
 * Convert an u16_t from network- to host byte order.
 *
 * @param n u16_t in network byte order
 * @return n in host byte order
 */
u16_t
ntohs(u16_t n)
{
  return htons(n);
}

/**
 * Convert an u32_t from host- to network byte order.
 *
 * @param n u32_t in host byte order
 * @return n in network byte order
 */
u32_t
htonl(u32_t n)
{
  return ((n & 0xff) << 24) |
    ((n & 0xff00) << 8) |
    ((n & 0xff0000UL) >> 8) |
    ((n & 0xff000000UL) >> 24);
}

/**
 * Convert an u32_t from network- to host byte order.
 *
 * @param n u32_t in network byte order
 * @return n in host byte order
 */
u32_t
ntohl(u32_t n)
{
  return htonl(n);
}

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