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