lwip_ip4_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 
00041 #if LWIP_IPV4
00042 
00043 #include "lwip/ip_addr.h"
00044 #include "lwip/netif.h"
00045 
00046 /* used by IP4_ADDR_ANY and IP_ADDR_BROADCAST in ip_addr.h */
00047 const ip_addr_t ip_addr_any = IPADDR4_INIT(IPADDR_ANY);
00048 const ip_addr_t ip_addr_broadcast = IPADDR4_INIT(IPADDR_BROADCAST);
00049 
00050 /**
00051  * Determine if an address is a broadcast address on a network interface
00052  *
00053  * @param addr address to be checked
00054  * @param netif the network interface against which the address is checked
00055  * @return returns non-zero if the address is a broadcast address
00056  */
00057 u8_t
00058 ip4_addr_isbroadcast_u32(u32_t addr, const struct netif *netif)
00059 {
00060   ip4_addr_t ipaddr;
00061   ip4_addr_set_u32(&ipaddr, addr);
00062 
00063   /* all ones (broadcast) or all zeroes (old skool broadcast) */
00064   if ((~addr == IPADDR_ANY) ||
00065       (addr == IPADDR_ANY)) {
00066     return 1;
00067   /* no broadcast support on this network interface? */
00068   } else if ((netif->flags & NETIF_FLAG_BROADCAST) == 0) {
00069     /* the given address cannot be a broadcast address
00070      * nor can we check against any broadcast addresses */
00071     return 0;
00072   /* address matches network interface address exactly? => no broadcast */
00073   } else if (addr == ip4_addr_get_u32(netif_ip4_addr(netif))) {
00074     return 0;
00075   /*  on the same (sub) network... */
00076   } else if (ip4_addr_netcmp(&ipaddr, netif_ip4_addr(netif), netif_ip4_netmask(netif))
00077          /* ...and host identifier bits are all ones? =>... */
00078           && ((addr & ~ip4_addr_get_u32(netif_ip4_netmask(netif))) ==
00079            (IPADDR_BROADCAST & ~ip4_addr_get_u32(netif_ip4_netmask(netif))))) {
00080     /* => network broadcast address */
00081     return 1;
00082   } else {
00083     return 0;
00084   }
00085 }
00086 
00087 /** Checks if a netmask is valid (starting with ones, then only zeros)
00088  *
00089  * @param netmask the IPv4 netmask to check (in network byte order!)
00090  * @return 1 if the netmask is valid, 0 if it is not
00091  */
00092 u8_t
00093 ip4_addr_netmask_valid(u32_t netmask)
00094 {
00095   u32_t mask;
00096   u32_t nm_hostorder = lwip_htonl(netmask);
00097 
00098   /* first, check for the first zero */
00099   for (mask = 1UL << 31 ; mask != 0; mask >>= 1) {
00100     if ((nm_hostorder & mask) == 0) {
00101       break;
00102     }
00103   }
00104   /* then check that there is no one */
00105   for (; mask != 0; mask >>= 1) {
00106     if ((nm_hostorder & mask) != 0) {
00107       /* there is a one after the first zero -> invalid */
00108       return 0;
00109     }
00110   }
00111   /* no one after the first zero -> valid */
00112   return 1;
00113 }
00114 
00115 /* Here for now until needed in other places in lwIP */
00116 #ifndef isprint
00117 #define in_range(c, lo, up)  ((u8_t)c >= lo && (u8_t)c <= up)
00118 #define isprint(c)           in_range(c, 0x20, 0x7f)
00119 #define isdigit(c)           in_range(c, '0', '9')
00120 #define isxdigit(c)          (isdigit(c) || in_range(c, 'a', 'f') || in_range(c, 'A', 'F'))
00121 #define islower(c)           in_range(c, 'a', 'z')
00122 #define isspace(c)           (c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v')
00123 #endif
00124 
00125 /**
00126  * Ascii internet address interpretation routine.
00127  * The value returned is in network order.
00128  *
00129  * @param cp IP address in ascii representation (e.g. "127.0.0.1")
00130  * @return ip address in network order
00131  */
00132 u32_t
00133 ipaddr_addr(const char *cp)
00134 {
00135   ip4_addr_t val;
00136 
00137   if (ip4addr_aton(cp, &val)) {
00138     return ip4_addr_get_u32(&val);
00139   }
00140   return (IPADDR_NONE);
00141 }
00142 
00143 /**
00144  * Check whether "cp" is a valid ascii representation
00145  * of an Internet address and convert to a binary address.
00146  * Returns 1 if the address is valid, 0 if not.
00147  * This replaces inet_addr, the return value from which
00148  * cannot distinguish between failure and a local broadcast address.
00149  *
00150  * @param cp IP address in ascii representation (e.g. "127.0.0.1")
00151  * @param addr pointer to which to save the ip address in network order
00152  * @return 1 if cp could be converted to addr, 0 on failure
00153  */
00154 int
00155 ip4addr_aton(const char *cp, ip4_addr_t *addr)
00156 {
00157   u32_t val;
00158   u8_t base;
00159   char c;
00160   u32_t parts[4];
00161   u32_t *pp = parts;
00162 
00163   c = *cp;
00164   for (;;) {
00165     /*
00166      * Collect number up to ``.''.
00167      * Values are specified as for C:
00168      * 0x=hex, 0=octal, 1-9=decimal.
00169      */
00170     if (!isdigit(c)) {
00171       return 0;
00172     }
00173     val = 0;
00174     base = 10;
00175     if (c == '0') {
00176       c = *++cp;
00177       if (c == 'x' || c == 'X') {
00178         base = 16;
00179         c = *++cp;
00180       } else {
00181         base = 8;
00182       }
00183     }
00184     for (;;) {
00185       if (isdigit(c)) {
00186         val = (val * base) + (u32_t)(c - '0');
00187         c = *++cp;
00188       } else if (base == 16 && isxdigit(c)) {
00189         val = (val << 4) | (u32_t)(c + 10 - (islower(c) ? 'a' : 'A'));
00190         c = *++cp;
00191       } else {
00192         break;
00193       }
00194     }
00195     if (c == '.') {
00196       /*
00197        * Internet format:
00198        *  a.b.c.d
00199        *  a.b.c   (with c treated as 16 bits)
00200        *  a.b (with b treated as 24 bits)
00201        */
00202       if (pp >= parts + 3) {
00203         return 0;
00204       }
00205       *pp++ = val;
00206       c = *++cp;
00207     } else {
00208       break;
00209     }
00210   }
00211   /*
00212    * Check for trailing characters.
00213    */
00214   if (c != '\0' && !isspace(c)) {
00215     return 0;
00216   }
00217   /*
00218    * Concoct the address according to
00219    * the number of parts specified.
00220    */
00221   switch (pp - parts + 1) {
00222 
00223   case 0:
00224     return 0;       /* initial nondigit */
00225 
00226   case 1:             /* a -- 32 bits */
00227     break;
00228 
00229   case 2:             /* a.b -- 8.24 bits */
00230     if (val > 0xffffffUL) {
00231       return 0;
00232     }
00233     if (parts[0] > 0xff) {
00234       return 0;
00235     }
00236     val |= parts[0] << 24;
00237     break;
00238 
00239   case 3:             /* a.b.c -- 8.8.16 bits */
00240     if (val > 0xffff) {
00241       return 0;
00242     }
00243     if ((parts[0] > 0xff) || (parts[1] > 0xff)) {
00244       return 0;
00245     }
00246     val |= (parts[0] << 24) | (parts[1] << 16);
00247     break;
00248 
00249   case 4:             /* a.b.c.d -- 8.8.8.8 bits */
00250     if (val > 0xff) {
00251       return 0;
00252     }
00253     if ((parts[0] > 0xff) || (parts[1] > 0xff) || (parts[2] > 0xff)) {
00254       return 0;
00255     }
00256     val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
00257     break;
00258   default:
00259     LWIP_ASSERT("unhandled", 0);
00260     break;
00261   }
00262   if (addr) {
00263     ip4_addr_set_u32(addr, lwip_htonl(val));
00264   }
00265   return 1;
00266 }
00267 
00268 /**
00269  * Convert numeric IP address into decimal dotted ASCII representation.
00270  * returns ptr to static buffer; not reentrant!
00271  *
00272  * @param addr ip address in network order to convert
00273  * @return pointer to a global static (!) buffer that holds the ASCII
00274  *         representation of addr
00275  */
00276 char*
00277 ip4addr_ntoa(const ip4_addr_t *addr)
00278 {
00279   static char str[IP4ADDR_STRLEN_MAX];
00280   return ip4addr_ntoa_r(addr, str, IP4ADDR_STRLEN_MAX);
00281 }
00282 
00283 /**
00284  * Same as ipaddr_ntoa, but reentrant since a user-supplied buffer is used.
00285  *
00286  * @param addr ip address in network order to convert
00287  * @param buf target buffer where the string is stored
00288  * @param buflen length of buf
00289  * @return either pointer to buf which now holds the ASCII
00290  *         representation of addr or NULL if buf was too small
00291  */
00292 char*
00293 ip4addr_ntoa_r(const ip4_addr_t *addr, char *buf, int buflen)
00294 {
00295   u32_t s_addr;
00296   char inv[3];
00297   char *rp;
00298   u8_t *ap;
00299   u8_t rem;
00300   u8_t n;
00301   u8_t i;
00302   int len = 0;
00303 
00304   s_addr = ip4_addr_get_u32(addr);
00305 
00306   rp = buf;
00307   ap = (u8_t *)&s_addr;
00308   for (n = 0; n < 4; n++) {
00309     i = 0;
00310     do {
00311       rem = *ap % (u8_t)10;
00312       *ap /= (u8_t)10;
00313       inv[i++] = (char)('0' + rem);
00314     } while (*ap);
00315     while (i--) {
00316       if (len++ >= buflen) {
00317         return NULL;
00318       }
00319       *rp++ = inv[i];
00320     }
00321     if (len++ >= buflen) {
00322       return NULL;
00323     }
00324     *rp++ = '.';
00325     ap++;
00326   }
00327   *--rp = 0;
00328   return buf;
00329 }
00330 
00331 #endif /* LWIP_IPV4 */