1 /* 2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (c) 1996-1999 by Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT 15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static const char rcsid[] = "$Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $"; 20 #endif /* LIBC_SCCS and not lint */ 21 #include <sys/cdefs.h> 22 #include <sys/param.h> 23 #include <sys/socket.h> 24 #include <sys/systm.h> 25 26 #include <netinet/in.h> 27 28 /*% 29 * WARNING: Don't even consider trying to compile this on a system where 30 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 31 */ 32 33 static char *inet_ntop4(const u_char *src, char *dst, socklen_t size); 34 static char *inet_ntop6(const u_char *src, char *dst, socklen_t size); 35 36 /* char * 37 * inet_ntop(af, src, dst, size) 38 * convert a network format address to presentation format. 39 * return: 40 * pointer to presentation format address (`dst'), or NULL (see errno). 41 * author: 42 * Paul Vixie, 1996. 43 */ 44 char * 45 inet_ntop(int af, const void *src, char *dst, socklen_t size) 46 { 47 switch (af) { 48 case AF_INET: 49 return (inet_ntop4(src, dst, size)); 50 case AF_INET6: 51 return (inet_ntop6(src, dst, size)); 52 default: 53 return (NULL); 54 } 55 /* NOTREACHED */ 56 } 57 58 /* const char * 59 * inet_ntop4(src, dst, size) 60 * format an IPv4 address 61 * return: 62 * `dst' (as a const) 63 * notes: 64 * (1) uses no statics 65 * (2) takes a u_char* not an in_addr as input 66 * author: 67 * Paul Vixie, 1996. 68 */ 69 static char * 70 inet_ntop4(const u_char *src, char *dst, socklen_t size) 71 { 72 static const char fmt[] = "%u.%u.%u.%u"; 73 char tmp[sizeof "255.255.255.255"]; 74 int l; 75 76 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 77 if (l <= 0 || (socklen_t) l >= size) { 78 return (NULL); 79 } 80 strlcpy(dst, tmp, size); 81 return (dst); 82 } 83 84 /* const char * 85 * inet_ntop6(src, dst, size) 86 * convert IPv6 binary address into presentation (printable) format 87 * author: 88 * Paul Vixie, 1996. 89 */ 90 static char * 91 inet_ntop6(const u_char *src, char *dst, socklen_t size) 92 { 93 /* 94 * Note that int32_t and int16_t need only be "at least" large enough 95 * to contain a value of the specified size. On some systems, like 96 * Crays, there is no such thing as an integer variable with 16 bits. 97 * Keep this in mind if you think this function should have been coded 98 * to use pointer overlays. All the world's not a VAX. 99 */ 100 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 101 struct { int base, len; } best, cur; 102 #define NS_IN6ADDRSZ 16 103 #define NS_INT16SZ 2 104 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 105 int i; 106 107 /* 108 * Preprocess: 109 * Copy the input (bytewise) array into a wordwise array. 110 * Find the longest run of 0x00's in src[] for :: shorthanding. 111 */ 112 memset(words, '\0', sizeof words); 113 for (i = 0; i < NS_IN6ADDRSZ; i++) 114 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 115 best.base = -1; 116 best.len = 0; 117 cur.base = -1; 118 cur.len = 0; 119 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 120 if (words[i] == 0) { 121 if (cur.base == -1) 122 cur.base = i, cur.len = 1; 123 else 124 cur.len++; 125 } else { 126 if (cur.base != -1) { 127 if (best.base == -1 || cur.len > best.len) 128 best = cur; 129 cur.base = -1; 130 } 131 } 132 } 133 if (cur.base != -1) { 134 if (best.base == -1 || cur.len > best.len) 135 best = cur; 136 } 137 if (best.base != -1 && best.len < 2) 138 best.base = -1; 139 140 /* 141 * Format the result. 142 */ 143 tp = tmp; 144 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 145 /* Are we inside the best run of 0x00's? */ 146 if (best.base != -1 && i >= best.base && 147 i < (best.base + best.len)) { 148 if (i == best.base) 149 *tp++ = ':'; 150 continue; 151 } 152 /* Are we following an initial run of 0x00s or any real hex? */ 153 if (i != 0) 154 *tp++ = ':'; 155 /* Is this address an encapsulated IPv4? */ 156 if (i == 6 && best.base == 0 && (best.len == 6 || 157 (best.len == 7 && words[7] != 0x0001) || 158 (best.len == 5 && words[5] == 0xffff))) { 159 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 160 return (NULL); 161 tp += strlen(tp); 162 break; 163 } 164 tp += sprintf(tp, "%x", words[i]); 165 } 166 /* Was it a trailing run of 0x00's? */ 167 if (best.base != -1 && (best.base + best.len) == 168 (NS_IN6ADDRSZ / NS_INT16SZ)) 169 *tp++ = ':'; 170 *tp++ = '\0'; 171 172 /* 173 * Check for overflow, copy, and we're done. 174 */ 175 if ((socklen_t)(tp - tmp) > size) { 176 return (NULL); 177 } 178 strcpy(dst, tmp); 179 return (dst); 180 } 181 182 /*! \file */ 183