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 $"; 20 #endif /* LIBC_SCCS and not lint */ 21 #include <sys/cdefs.h> 22 __FBSDID("$FreeBSD$"); 23 24 #include <sys/param.h> 25 #include <sys/socket.h> 26 #include <sys/systm.h> 27 28 #include <netinet/in.h> 29 30 /*% 31 * WARNING: Don't even consider trying to compile this on a system where 32 * sizeof(int) < 4. sizeof(int) > 4 is fine; all the world's not a VAX. 33 */ 34 35 static char *inet_ntop4(const u_char *src, char *dst, socklen_t size); 36 static char *inet_ntop6(const u_char *src, char *dst, socklen_t size); 37 38 /* char * 39 * inet_ntop(af, src, dst, size) 40 * convert a network format address to presentation format. 41 * return: 42 * pointer to presentation format address (`dst'), or NULL (see errno). 43 * author: 44 * Paul Vixie, 1996. 45 */ 46 char * 47 inet_ntop(int af, const void *src, char *dst, socklen_t size) 48 { 49 switch (af) { 50 case AF_INET: 51 return (inet_ntop4(src, dst, size)); 52 case AF_INET6: 53 return (inet_ntop6(src, dst, size)); 54 default: 55 return (NULL); 56 } 57 /* NOTREACHED */ 58 } 59 60 /* const char * 61 * inet_ntop4(src, dst, size) 62 * format an IPv4 address 63 * return: 64 * `dst' (as a const) 65 * notes: 66 * (1) uses no statics 67 * (2) takes a u_char* not an in_addr as input 68 * author: 69 * Paul Vixie, 1996. 70 */ 71 static char * 72 inet_ntop4(const u_char *src, char *dst, socklen_t size) 73 { 74 static const char fmt[] = "%u.%u.%u.%u"; 75 char tmp[sizeof "255.255.255.255"]; 76 int l; 77 78 l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]); 79 if (l <= 0 || (socklen_t) l >= size) { 80 return (NULL); 81 } 82 strlcpy(dst, tmp, size); 83 return (dst); 84 } 85 86 /* const char * 87 * inet_ntop6(src, dst, size) 88 * convert IPv6 binary address into presentation (printable) format 89 * author: 90 * Paul Vixie, 1996. 91 */ 92 static char * 93 inet_ntop6(const u_char *src, char *dst, socklen_t size) 94 { 95 /* 96 * Note that int32_t and int16_t need only be "at least" large enough 97 * to contain a value of the specified size. On some systems, like 98 * Crays, there is no such thing as an integer variable with 16 bits. 99 * Keep this in mind if you think this function should have been coded 100 * to use pointer overlays. All the world's not a VAX. 101 */ 102 char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp; 103 struct { int base, len; } best, cur; 104 #define NS_IN6ADDRSZ 16 105 #define NS_INT16SZ 2 106 u_int words[NS_IN6ADDRSZ / NS_INT16SZ]; 107 int i; 108 109 /* 110 * Preprocess: 111 * Copy the input (bytewise) array into a wordwise array. 112 * Find the longest run of 0x00's in src[] for :: shorthanding. 113 */ 114 memset(words, '\0', sizeof words); 115 for (i = 0; i < NS_IN6ADDRSZ; i++) 116 words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3)); 117 best.base = -1; 118 best.len = 0; 119 cur.base = -1; 120 cur.len = 0; 121 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 122 if (words[i] == 0) { 123 if (cur.base == -1) 124 cur.base = i, cur.len = 1; 125 else 126 cur.len++; 127 } else { 128 if (cur.base != -1) { 129 if (best.base == -1 || cur.len > best.len) 130 best = cur; 131 cur.base = -1; 132 } 133 } 134 } 135 if (cur.base != -1) { 136 if (best.base == -1 || cur.len > best.len) 137 best = cur; 138 } 139 if (best.base != -1 && best.len < 2) 140 best.base = -1; 141 142 /* 143 * Format the result. 144 */ 145 tp = tmp; 146 for (i = 0; i < (NS_IN6ADDRSZ / NS_INT16SZ); i++) { 147 /* Are we inside the best run of 0x00's? */ 148 if (best.base != -1 && i >= best.base && 149 i < (best.base + best.len)) { 150 if (i == best.base) 151 *tp++ = ':'; 152 continue; 153 } 154 /* Are we following an initial run of 0x00s or any real hex? */ 155 if (i != 0) 156 *tp++ = ':'; 157 /* Is this address an encapsulated IPv4? */ 158 if (i == 6 && best.base == 0 && (best.len == 6 || 159 (best.len == 7 && words[7] != 0x0001) || 160 (best.len == 5 && words[5] == 0xffff))) { 161 if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp))) 162 return (NULL); 163 tp += strlen(tp); 164 break; 165 } 166 tp += sprintf(tp, "%x", words[i]); 167 } 168 /* Was it a trailing run of 0x00's? */ 169 if (best.base != -1 && (best.base + best.len) == 170 (NS_IN6ADDRSZ / NS_INT16SZ)) 171 *tp++ = ':'; 172 *tp++ = '\0'; 173 174 /* 175 * Check for overflow, copy, and we're done. 176 */ 177 if ((socklen_t)(tp - tmp) > size) { 178 return (NULL); 179 } 180 strcpy(dst, tmp); 181 return (dst); 182 } 183 184 /*! \file */ 185