ip_addr.c

00001 /**
00002  * @file
00003  * This is the IPv4 address tools implementation.
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 #include "lwip/ip_addr.h"
00041 #include "lwip/netif.h"
00042 
00043 /* used by IP_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
00044 const ip_addr_t ip_addr_any = { IPADDR_ANY };
00045 const ip_addr_t ip_addr_broadcast = { IPADDR_BROADCAST };
00046 
00047 /**
00048  * Determine if an address is a broadcast address on a network interface 
00049  * 
00050  * @param addr address to be checked
00051  * @param netif the network interface against which the address is checked
00052  * @return returns non-zero if the address is a broadcast address
00053  */
00054 u8_t
00055 ip4_addr_isbroadcast(u32_t addr, const struct netif *netif)
00056 {
00057   ip_addr_t ipaddr;
00058   ip4_addr_set_u32(&ipaddr, addr);
00059 
00060   /* all ones (broadcast) or all zeroes (old skool broadcast) */
00061   if ((~addr == IPADDR_ANY) ||
00062       (addr == IPADDR_ANY)) {
00063     return 1;
00064   /* no broadcast support on this network interface? */
00065   } else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
00066     /* the given address cannot be a broadcast address
00067      * nor can we check against any broadcast addresses */
00068     return 0;
00069   /* address matches network interface address exactly? => no broadcast */
00070   } else if (addr == ip4_addr_get_u32(&netif->ip_addr)) {
00071     return 0;
00072   /*  on the same (sub) network... */
00073   } else if (ip_addr_netcmp(&ipaddr, &(netif->ip_addr), &(netif->netmask))
00074          /* ...and host identifier bits are all ones? =>... */
00075           && ((addr & ~ip4_addr_get_u32(&netif->netmask)) ==
00076            (IPADDR_BROADCAST & ~ip4_addr_get_u32(&netif->netmask)))) {
00077     /* => network broadcast address */
00078     return 1;
00079   } else {
00080     return 0;
00081   }
00082 }
00083 
00084 /** Checks if a netmask is valid (starting with ones, then only zeros)
00085  *
00086  * @param netmask the IPv4 netmask to check (in network byte order!)
00087  * @return 1 if the netmask is valid, 0 if it is not
00088  */
00089 u8_t
00090 ip4_addr_netmask_valid(u32_t netmask)
00091 {
00092   u32_t mask;
00093   u32_t nm_hostorder = lwip_htonl(netmask);
00094 
00095   /* first, check for the first zero */
00096   for (mask = 1U << 31 ; mask != 0; mask >>= 1) {
00097     if ((nm_hostorder & mask) == 0) {
00098       break;
00099     }
00100   }
00101   /* then check that there is no one */
00102   for (; mask != 0; mask >>= 1) {
00103     if ((nm_hostorder & mask) != 0) {
00104       /* there is a one after the first zero -> invalid */
00105       return 0;
00106     }
00107   }
00108   /* no one after the first zero -> valid */
00109   return 1;
00110 }
00111 
00112 /* Here for now until needed in other places in lwIP */
00113 #ifndef isprint
00114 #define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
00115 #define isprint(c)           in_range(c, 0x20, 0x7f)
00116 #define isdigit(c)           in_range(c, '0', '9')
00117 #define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
00118 #define islower(c)           in_range(c, 'a', 'z')
00119 #define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
00120 #endif
00121 
00122 /**
00123  * Ascii internet address interpretation routine.
00124  * The value returned is in network order.
00125  *
00126  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
00127  * @return ip address in network order
00128  */
00129 u32_t
00130 ipaddr_addr(const char *cp)
00131 {
00132   ip_addr_t val;
00133 
00134   if (ipaddr_aton(cp, &val)) {
00135     return ip4_addr_get_u32(&val);
00136   }
00137   return (IPADDR_NONE);
00138 }
00139 
00140 /**
00141  * Check whether "cp" is a valid ascii representation
00142  * of an Internet address and convert to a binary address.
00143  * Returns 1 if the address is valid, 0 if not.
00144  * This replaces inet_addr, the return value from which
00145  * cannot distinguish between failure and a local broadcast address.
00146  *
00147  * @param cp IP address in ascii represenation (e.g. "127.0.0.1")
00148  * @param addr pointer to which to save the ip address in network order
00149  * @return 1 if cp could be converted to addr, 0 on failure
00150  */
00151 int
00152 ipaddr_aton(const char *cp, ip_addr_t *addr)
00153 {
00154   u32_t val;
00155   u8_t base;
00156   char c;
00157   u32_t parts[4];
00158   u32_t *pp = parts;
00159 
00160   c = *cp;
00161   for (;;) {
00162     /*
00163      * Collect number up to ``.''.
00164      * Values are specified as for C:
00165      * 0x=hex, 0=octal, 1-9=decimal.
00166      */
00167     if (!isdigit(c))
00168       return (0);
00169     val = 0;
00170     base = 10;
00171     if (c == '0') {
00172       c = *++cp;
00173       if (c == 'x' || c == 'X') {
00174         base = 16;
00175         c = *++cp;
00176       } else
00177         base = 8;
00178     }
00179     for (;;) {
00180       if (isdigit(c)) {
00181         val = (val * base) + (int)(c - '0');
00182         c = *++cp;
00183       } else if (base == 16 && isxdigit(c)) {
00184         val = (val << 4) | (int)(c + 10 - (islower(c) ? 'a' : 'A'));
00185         c = *++cp;
00186       } else
00187         break;
00188     }
00189     if (c == '.') {
00190       /*
00191        * Internet format:
00192        *  a.b.c.d
00193        *  a.b.c   (with c treated as 16 bits)
00194        *  a.b (with b treated as 24 bits)
00195        */
00196       if (pp >= parts + 3) {
00197         return (0);
00198       }
00199       *pp++ = val;
00200       c = *++cp;
00201     } else
00202       break;
00203   }
00204   /*
00205    * Check for trailing characters.
00206    */
00207   if (c != '\0' && !isspace(c)) {
00208     return (0);
00209   }
00210   /*
00211    * Concoct the address according to
00212    * the number of parts specified.
00213    */
00214   switch (pp - parts + 1) {
00215 
00216   case 0:
00217     return (0);       /* initial nondigit */
00218 
00219   case 1:             /* a -- 32 bits */
00220     break;
00221 
00222   case 2:             /* a.b -- 8.24 bits */
00223     if (val > 0xffffffUL) {
00224       return (0);
00225     }
00226     val |= parts[0] << 24;
00227     break;
00228 
00229   case 3:             /* a.b.c -- 8.8.16 bits */
00230     if (val > 0xffff) {
00231       return (0);
00232     }
00233     val |= (parts[0] << 24) | (parts[1] << 16);
00234     break;
00235 
00236   case 4:             /* a.b.c.d -- 8.8.8.8 bits */
00237     if (val > 0xff) {
00238       return (0);
00239     }
00240     val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
00241     break;
00242   default:
00243     LWIP_ASSERT("unhandled", 0);
00244     break;
00245   }
00246   if (addr) {
00247     ip4_addr_set_u32(addr, htonl(val));
00248   }
00249   return (1);
00250 }
00251 
00252 /**
00253  * Convert numeric IP address into decimal dotted ASCII representation.
00254  * returns ptr to static buffer; not reentrant!
00255  *
00256  * @param addr ip address in network order to convert
00257  * @return pointer to a global static (!) buffer that holds the ASCII
00258  *         represenation of addr
00259  */
00260 char *
00261 ipaddr_ntoa(const ip_addr_t *addr)
00262 {
00263   static char str[16];
00264   return ipaddr_ntoa_r(addr, str, 16);
00265 }
00266 
00267 /**
00268  * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
00269  *
00270  * @param addr ip address in network order to convert
00271  * @param buf target buffer where the string is stored
00272  * @param buflen length of buf
00273  * @return either pointer to buf which now holds the ASCII
00274  *         representation of addr or NULL if buf was too small
00275  */
00276 char *ipaddr_ntoa_r(const ip_addr_t *addr, char *buf, int buflen)
00277 {
00278   u32_t s_addr;
00279   char inv[3];
00280   char *rp;
00281   u8_t *ap;
00282   u8_t rem;
00283   u8_t n;
00284   u8_t i;
00285   int len = 0;
00286 
00287   s_addr = ip4_addr_get_u32(addr);
00288 
00289   rp = buf;
00290   ap = (u8_t *)&s_addr;
00291   for(n = 0; n < 4; n++) {
00292     i = 0;
00293     do {
00294       rem = *ap % (u8_t)10;
00295       *ap /= (u8_t)10;
00296       inv[i++] = '0' + rem;
00297     } while(*ap);
00298     while(i--) {
00299       if (len++ >= buflen) {
00300         return NULL;
00301       }
00302       *rp++ = inv[i];
00303     }
00304     if (len++ >= buflen) {
00305       return NULL;
00306     }
00307     *rp++ = '.';
00308     ap++;
00309   }
00310   *--rp = 0;
00311   return buf;
00312 }