inet.c

00001 /**
00002  * @file
00003  * Functions common to all TCP/IPv4 modules, such as the byte order functions.
00004  *
00005  */
00006 
00007 /*
00008  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
00009  * All rights reserved.
00010  *
00011  * Redistribution and use in source and binary forms, with or without modification,
00012  * are permitted provided that the following conditions are met:
00013  *
00014  * 1. Redistributions of source code must retain the above copyright notice,
00015  *    this list of conditions and the following disclaimer.
00016  * 2. Redistributions in binary form must reproduce the above copyright notice,
00017  *    this list of conditions and the following disclaimer in the documentation
00018  *    and/or other materials provided with the distribution.
00019  * 3. The name of the author may not be used to endorse or promote products
00020  *    derived from this software without specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00023  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00024  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00025  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00026  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00027  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00028  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00029  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00030  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00031  * OF SUCH DAMAGE.
00032  *
00033  * This file is part of the lwIP TCP/IP stack.
00034  *
00035  * Author: Adam Dunkels <adam@sics.se>
00036  *
00037  */
00038 
00039 #include "lwip/opt.h"
00040 
00041 #include "lwip/inet.h"
00042 
00043 /* Here for now until needed in other places in lwIP */
00044 #ifndef isprint
00045 #define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
00046 #define isprint(c)           in_range(c, 0x20, 0x7f)
00047 #define isdigit(c)           in_range(c, '0', '9')
00048 #define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
00049 #define islower(c)           in_range(c, 'a', 'z')
00050 #define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
00051 #endif    
00052     
00053 /**
00054  * Ascii internet address interpretation routine.
00055  * The value returned is in network order.
00056  *
00057  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
00058  * @return ip address in network order
00059  */
00060 u32_t
00061 inet_addr(const char *cp)
00062 {
00063   struct in_addr val;
00064 
00065   if (inet_aton(cp, &val)) {
00066     return (val.s_addr);
00067   }
00068   return (INADDR_NONE);
00069 }
00070 
00071 /**
00072  * Check whether "cp" is a valid ascii representation
00073  * of an Internet address and convert to a binary address.
00074  * Returns 1 if the address is valid, 0 if not.
00075  * This replaces inet_addr, the return value from which
00076  * cannot distinguish between failure and a local broadcast address.
00077  *
00078  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
00079  * @param addr pointer to which to save the ip address in network order
00080  * @return 1 if cp could be converted to addr, 0 on failure
00081  */
00082 int
00083 inet_aton(const char *cp, struct in_addr *addr)
00084 {
00085   u32_t val;
00086   u8_t base;
00087   char c;
00088   u32_t parts[4];
00089   u32_t *pp = parts;
00090 
00091   c = *cp;
00092   for (;;) {
00093     /*
00094      * Collect number up to ``.''.
00095      * Values are specified as for C:
00096      * 0x=hex, 0=octal, 1-9=decimal.
00097      */
00098     if (!isdigit(c))
00099       return (0);
00100     val = 0;
00101     base = 10;
00102     if (c == '0') {
00103       c = *++cp;
00104       if (c == 'x' || c == 'X') {
00105         base = 16;
00106         c = *++cp;
00107       } else
00108         base = 8;
00109     }
00110     for (;;) {
00111       if (isdigit(c)) {
00112         val = (val * base) + (int)(c - '0');
00113         c = *++cp;
00114       } else if (base == 16 && isxdigit(c)) {
00115         val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
00116         c = *++cp;
00117       } else
00118         break;
00119     }
00120     if (c == '.') {
00121       /*
00122        * Internet format:
00123        *  a.b.c.d
00124        *  a.b.c   (with c treated as 16 bits)
00125        *  a.b (with b treated as 24 bits)
00126        */
00127       if (pp >= parts + 3)
00128         return (0);
00129       *pp++ = val;
00130       c = *++cp;
00131     } else
00132       break;
00133   }
00134   /*
00135    * Check for trailing characters.
00136    */
00137   if (c != '\0' && !isspace(c))
00138     return (0);
00139   /*
00140    * Concoct the address according to
00141    * the number of parts specified.
00142    */
00143   switch (pp - parts + 1) {
00144 
00145   case 0:
00146     return (0);       /* initial nondigit */
00147 
00148   case 1:             /* a -- 32 bits */
00149     break;
00150 
00151   case 2:             /* a.b -- 8.24 bits */
00152     if (val > 0xffffffUL)
00153       return (0);
00154     val |= parts[0] << 24;
00155     break;
00156 
00157   case 3:             /* a.b.c -- 8.8.16 bits */
00158     if (val > 0xffff)
00159       return (0);
00160     val |= (parts[0] << 24) | (parts[1] << 16);
00161     break;
00162 
00163   case 4:             /* a.b.c.d -- 8.8.8.8 bits */
00164     if (val > 0xff)
00165       return (0);
00166     val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
00167     break;
00168   }
00169   if (addr)
00170     addr->s_addr = htonl(val);
00171   return (1);
00172 }
00173 
00174 /**
00175  * Convert numeric IP address into decimal dotted ASCII representation.
00176  * returns ptr to static buffer; not reentrant!
00177  *
00178  * @param addr ip address in network order to convert
00179  * @return pointer to a global static (!) buffer that holds the ASCII
00180  *         represenation of addr
00181  */
00182 char *
00183 inet_ntoa(struct in_addr addr)
00184 {
00185   static char str[16];
00186   u32_t s_addr = addr.s_addr;
00187   char inv[3];
00188   char *rp;
00189   u8_t *ap;
00190   u8_t rem;
00191   u8_t n;
00192   u8_t i;
00193 
00194   rp = str;
00195   ap = (u8_t *)&s_addr;
00196   for(n = 0; n < 4; n++) {
00197     i = 0;
00198     do {
00199       rem = *ap % (u8_t)10;
00200       *ap /= (u8_t)10;
00201       inv[i++] = '0' + rem;
00202     } while(*ap);
00203     while(i--)
00204       *rp++ = inv[i];
00205     *rp++ = '.';
00206     ap++;
00207   }
00208   *--rp = 0;
00209   return str;
00210 }
00211 
00212 /**
00213  * These are reference implementations of the byte swapping functions.
00214  * Again with the aim of being simple, correct and fully portable.
00215  * Byte swapping is the second thing you would want to optimize. You will
00216  * need to port it to your architecture and in your cc.h:
00217  * 
00218  * #define LWIP_PLATFORM_BYTESWAP 1
00219  * #define LWIP_PLATFORM_HTONS(x) <your_htons>
00220  * #define LWIP_PLATFORM_HTONL(x) <your_htonl>
00221  *
00222  * Note ntohs() and ntohl() are merely references to the htonx counterparts.
00223  */
00224 
00225 #if (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN)
00226 
00227 /**
00228  * Convert an u16_t from host- to network byte order.
00229  *
00230  * @param n u16_t in host byte order
00231  * @return n in network byte order
00232  */
00233 u16_t
00234 htons(u16_t n)
00235 {
00236   return ((n & 0xff) << 8) | ((n & 0xff00) >> 8);
00237 }
00238 
00239 /**
00240  * Convert an u16_t from network- to host byte order.
00241  *
00242  * @param n u16_t in network byte order
00243  * @return n in host byte order
00244  */
00245 u16_t
00246 ntohs(u16_t n)
00247 {
00248   return htons(n);
00249 }
00250 
00251 /**
00252  * Convert an u32_t from host- to network byte order.
00253  *
00254  * @param n u32_t in host byte order
00255  * @return n in network byte order
00256  */
00257 u32_t
00258 htonl(u32_t n)
00259 {
00260   return ((n & 0xff) << 24) |
00261     ((n & 0xff00) << 8) |
00262     ((n & 0xff0000UL) >> 8) |
00263     ((n & 0xff000000UL) >> 24);
00264 }
00265 
00266 /**
00267  * Convert an u32_t from network- to host byte order.
00268  *
00269  * @param n u32_t in network byte order
00270  * @return n in host byte order
00271  */
00272 u32_t
00273 ntohl(u32_t n)
00274 {
00275   return htonl(n);
00276 }
00277 
00278 #endif /* (LWIP_PLATFORM_BYTESWAP == 0) && (BYTE_ORDER == LITTLE_ENDIAN) */