Annotation of embedaddon/curl/lib/inet_ntop.c, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (C) 1996-2019  Internet Software Consortium.
                      3:  *
                      4:  * Permission to use, copy, modify, and distribute this software for any
                      5:  * purpose with or without fee is hereby granted, provided that the above
                      6:  * copyright notice and this permission notice appear in all copies.
                      7:  *
                      8:  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
                      9:  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
                     10:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
                     11:  * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
                     12:  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
                     13:  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
                     14:  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
                     15:  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
                     16:  */
                     17: /*
                     18:  * Original code by Paul Vixie. "curlified" by Gisle Vanem.
                     19:  */
                     20: 
                     21: #include "curl_setup.h"
                     22: 
                     23: #ifndef HAVE_INET_NTOP
                     24: 
                     25: #ifdef HAVE_SYS_PARAM_H
                     26: #include <sys/param.h>
                     27: #endif
                     28: #ifdef HAVE_NETINET_IN_H
                     29: #include <netinet/in.h>
                     30: #endif
                     31: #ifdef HAVE_ARPA_INET_H
                     32: #include <arpa/inet.h>
                     33: #endif
                     34: 
                     35: #include "inet_ntop.h"
                     36: #include "curl_printf.h"
                     37: 
                     38: #define IN6ADDRSZ       16
                     39: #define INADDRSZ         4
                     40: #define INT16SZ          2
                     41: 
                     42: /*
                     43:  * Format an IPv4 address, more or less like inet_ntoa().
                     44:  *
                     45:  * Returns `dst' (as a const)
                     46:  * Note:
                     47:  *  - uses no statics
                     48:  *  - takes a unsigned char* not an in_addr as input
                     49:  */
                     50: static char *inet_ntop4 (const unsigned char *src, char *dst, size_t size)
                     51: {
                     52:   char tmp[sizeof("255.255.255.255")];
                     53:   size_t len;
                     54: 
                     55:   DEBUGASSERT(size >= 16);
                     56: 
                     57:   tmp[0] = '\0';
                     58:   (void)msnprintf(tmp, sizeof(tmp), "%d.%d.%d.%d",
                     59:                   ((int)((unsigned char)src[0])) & 0xff,
                     60:                   ((int)((unsigned char)src[1])) & 0xff,
                     61:                   ((int)((unsigned char)src[2])) & 0xff,
                     62:                   ((int)((unsigned char)src[3])) & 0xff);
                     63: 
                     64:   len = strlen(tmp);
                     65:   if(len == 0 || len >= size) {
                     66:     errno = ENOSPC;
                     67:     return (NULL);
                     68:   }
                     69:   strcpy(dst, tmp);
                     70:   return dst;
                     71: }
                     72: 
                     73: #ifdef ENABLE_IPV6
                     74: /*
                     75:  * Convert IPv6 binary address into presentation (printable) format.
                     76:  */
                     77: static char *inet_ntop6 (const unsigned char *src, char *dst, size_t size)
                     78: {
                     79:   /*
                     80:    * Note that int32_t and int16_t need only be "at least" large enough
                     81:    * to contain a value of the specified size.  On some systems, like
                     82:    * Crays, there is no such thing as an integer variable with 16 bits.
                     83:    * Keep this in mind if you think this function should have been coded
                     84:    * to use pointer overlays.  All the world's not a VAX.
                     85:    */
                     86:   char tmp[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
                     87:   char *tp;
                     88:   struct {
                     89:     long base;
                     90:     long len;
                     91:   } best, cur;
                     92:   unsigned long words[IN6ADDRSZ / INT16SZ];
                     93:   int i;
                     94: 
                     95:   /* Preprocess:
                     96:    *  Copy the input (bytewise) array into a wordwise array.
                     97:    *  Find the longest run of 0x00's in src[] for :: shorthanding.
                     98:    */
                     99:   memset(words, '\0', sizeof(words));
                    100:   for(i = 0; i < IN6ADDRSZ; i++)
                    101:     words[i/2] |= (src[i] << ((1 - (i % 2)) << 3));
                    102: 
                    103:   best.base = -1;
                    104:   cur.base  = -1;
                    105:   best.len = 0;
                    106:   cur.len = 0;
                    107: 
                    108:   for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
                    109:     if(words[i] == 0) {
                    110:       if(cur.base == -1)
                    111:         cur.base = i, cur.len = 1;
                    112:       else
                    113:         cur.len++;
                    114:     }
                    115:     else if(cur.base != -1) {
                    116:       if(best.base == -1 || cur.len > best.len)
                    117:         best = cur;
                    118:       cur.base = -1;
                    119:     }
                    120:   }
                    121:   if((cur.base != -1) && (best.base == -1 || cur.len > best.len))
                    122:     best = cur;
                    123:   if(best.base != -1 && best.len < 2)
                    124:     best.base = -1;
                    125:   /* Format the result. */
                    126:   tp = tmp;
                    127:   for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
                    128:     /* Are we inside the best run of 0x00's? */
                    129:     if(best.base != -1 && i >= best.base && i < (best.base + best.len)) {
                    130:       if(i == best.base)
                    131:         *tp++ = ':';
                    132:       continue;
                    133:     }
                    134: 
                    135:     /* Are we following an initial run of 0x00s or any real hex?
                    136:      */
                    137:     if(i != 0)
                    138:       *tp++ = ':';
                    139: 
                    140:     /* Is this address an encapsulated IPv4?
                    141:      */
                    142:     if(i == 6 && best.base == 0 &&
                    143:         (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
                    144:       if(!inet_ntop4(src + 12, tp, sizeof(tmp) - (tp - tmp))) {
                    145:         errno = ENOSPC;
                    146:         return (NULL);
                    147:       }
                    148:       tp += strlen(tp);
                    149:       break;
                    150:     }
                    151:     tp += msnprintf(tp, 5, "%lx", words[i]);
                    152:   }
                    153: 
                    154:   /* Was it a trailing run of 0x00's?
                    155:    */
                    156:   if(best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
                    157:      *tp++ = ':';
                    158:   *tp++ = '\0';
                    159: 
                    160:   /* Check for overflow, copy, and we're done.
                    161:    */
                    162:   if((size_t)(tp - tmp) > size) {
                    163:     errno = ENOSPC;
                    164:     return (NULL);
                    165:   }
                    166:   strcpy(dst, tmp);
                    167:   return dst;
                    168: }
                    169: #endif  /* ENABLE_IPV6 */
                    170: 
                    171: /*
                    172:  * Convert a network format address to presentation format.
                    173:  *
                    174:  * Returns pointer to presentation format address (`buf').
                    175:  * Returns NULL on error and errno set with the specific
                    176:  * error, EAFNOSUPPORT or ENOSPC.
                    177:  *
                    178:  * On Windows we store the error in the thread errno, not
                    179:  * in the winsock error code. This is to avoid losing the
                    180:  * actual last winsock error. So when this function returns
                    181:  * NULL, check errno not SOCKERRNO.
                    182:  */
                    183: char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size)
                    184: {
                    185:   switch(af) {
                    186:   case AF_INET:
                    187:     return inet_ntop4((const unsigned char *)src, buf, size);
                    188: #ifdef ENABLE_IPV6
                    189:   case AF_INET6:
                    190:     return inet_ntop6((const unsigned char *)src, buf, size);
                    191: #endif
                    192:   default:
                    193:     errno = EAFNOSUPPORT;
                    194:     return NULL;
                    195:   }
                    196: }
                    197: #endif  /* HAVE_INET_NTOP */

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