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 * $Id: inet_ntop.c,v 1.3.18.2 2005/11/03 23:02:22 marka Exp $ 18 * FreeBSD r213103 19 */ 20 21 #include <sys/param.h> 22 #include <sys/socket.h> 23 #include <sys/systm.h> 24 25 #include <netinet/in.h> 26 27 /*% 28 * WARNING: Don't even consider trying to compile this on a system where 29 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 30 */ 31 32 static char *inet_ntop4(const u_char *src, char *dst, socklen_t size); 33 static char *inet_ntop6(const u_char *src, char *dst, socklen_t size); 34 35 /* char * 36 * inet_ntop(af, src, dst, size) 37 * convert a network format address to presentation format. 38 * return: 39 * pointer to presentation format address (`dst'), or NULL (see errno). 40 * author: 41 * Paul Vixie, 1996. 42 */ 43 char * 44 inet_ntop(int af, const void *src, char *dst, socklen_t size) 45 { 46 switch (af) { 47 case AF_INET: 48 return (inet_ntop4(src, dst, size)); 49 case AF_INET6: 50 return (inet_ntop6(src, dst, size)); 51 default: 52 return (NULL); 53 } 54 /* NOTREACHED */ 55 } 56 57 /* const char * 58 * inet_ntop4(src, dst, size) 59 * format an IPv4 address 60 * return: 61 * `dst' (as a const) 62 * notes: 63 * (1) uses no statics 64 * (2) takes a u_char* not an in_addr as input 65 * author: 66 * Paul Vixie, 1996. 67 */ 68 static char * 69 inet_ntop4(const u_char *src, char *dst, socklen_t size) 70 { 71 static const char fmt[] = "%u.%u.%u.%u"; 72 char tmp[sizeof "255.255.255.255"]; 73 int l; 74 75 l = ksnprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 76 if (l <= 0 || (socklen_t) l >= size) { 77 return (NULL); 78 } 79 strlcpy(dst, tmp, size); 80 return (dst); 81 } 82 83 /* const char * 84 * inet_ntop6(src, dst, size) 85 * convert IPv6 binary address into presentation (printable) format 86 * author: 87 * Paul Vixie, 1996. 88 */ 89 static char * 90 inet_ntop6(const u_char *src, char *dst, socklen_t size) 91 { 92 /* 93 * Note that int32_t and int16_t need only be "at least" large enough 94 * to contain a value of the specified size. On some systems, like 95 * Crays, there is no such thing as an integer variable with 16 bits. 96 * Keep this in mind if you think this function should have been coded 97 * to use pointer overlays. All the world's not a VAX. 98 */ 99 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 100 struct { int base, len; } best, cur; 101 #define NS_IN6ADDRSZ 16 102 #define NS_INT16SZ 2 103 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 104 int i; 105 106 /* 107 * Preprocess: 108 * Copy the input (bytewise) array into a wordwise array. 109 * Find the longest run of 0x00's in src[] for :: shorthanding. 110 */ 111 memset(words, '\0', sizeof words); 112 for (i = 0; i < NS_IN6ADDRSZ; i++) 113 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 114 best.base = -1; 115 best.len = 0; 116 cur.base = -1; 117 cur.len = 0; 118 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 119 if (words[i] == 0) { 120 if (cur.base == -1) 121 cur.base = i, cur.len = 1; 122 else 123 cur.len++; 124 } else { 125 if (cur.base != -1) { 126 if (best.base == -1 || cur.len > best.len) 127 best = cur; 128 cur.base = -1; 129 } 130 } 131 } 132 if (cur.base != -1) { 133 if (best.base == -1 || cur.len > best.len) 134 best = cur; 135 } 136 if (best.base != -1 && best.len < 2) 137 best.base = -1; 138 139 /* 140 * Format the result. 141 */ 142 tp = tmp; 143 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 144 /* Are we inside the best run of 0x00's? */ 145 if (best.base != -1 && i >= best.base && 146 i < (best.base + best.len)) { 147 if (i == best.base) 148 *tp++ = ':'; 149 continue; 150 } 151 /* Are we following an initial run of 0x00s or any real hex? */ 152 if (i != 0) 153 *tp++ = ':'; 154 /* Is this address an encapsulated IPv4? */ 155 if (i == 6 && best.base == 0 && (best.len == 6 || 156 (best.len == 7 && words[7] != 0x0001) || 157 (best.len == 5 && words[5] == 0xffff))) { 158 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 159 return (NULL); 160 tp += strlen(tp); 161 break; 162 } 163 tp += ksprintf(tp, "%x", words[i]); 164 } 165 /* Was it a trailing run of 0x00's? */ 166 if (best.base != -1 && (best.base + best.len) == 167 (NS_IN6ADDRSZ / NS_INT16SZ)) 168 *tp++ = ':'; 169 *tp++ = '\0'; 170 171 /* 172 * Check for overflow, copy, and we're done. 173 */ 174 if ((socklen_t)(tp - tmp) > size) { 175 return (NULL); 176 } 177 strcpy(dst, tmp); 178 return (dst); 179 } 180 181 /*! \file */ 182