1 /* $OpenBSD: inet_net_ntop.c,v 1.7 2012/06/22 19:13:37 gilles Exp $ */ 2 3 /* 4 * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org> 5 * Copyright (c) 1996 by Internet Software Consortium. 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS 12 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES 13 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE 14 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL 15 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR 16 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS 17 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS 18 * SOFTWARE. 19 */ 20 21 #include <sys/types.h> 22 #include <sys/socket.h> 23 #include <netinet/in.h> 24 #include <arpa/inet.h> 25 26 #include <errno.h> 27 #include <stdio.h> 28 #include <string.h> 29 #include <stdlib.h> 30 31 static char *inet_net_ntop_ipv4(const u_char *, int, char *, size_t); 32 static char *inet_net_ntop_ipv6(const u_char *, int, char *, size_t); 33 34 /* 35 * char * 36 * inet_net_ntop(af, src, bits, dst, size) 37 * convert network number from network to presentation format. 38 * generates CIDR style result always. 39 * return: 40 * pointer to dst, or NULL if an error occurred (check errno). 41 * author: 42 * Paul Vixie (ISC), July 1996 43 */ 44 char * 45 inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size) 46 { 47 switch (af) { 48 case AF_INET: 49 return (inet_net_ntop_ipv4(src, bits, dst, size)); 50 case AF_INET6: 51 return (inet_net_ntop_ipv6(src, bits, dst, size)); 52 default: 53 errno = EAFNOSUPPORT; 54 return (NULL); 55 } 56 } 57 58 /* 59 * static char * 60 * inet_net_ntop_ipv4(src, bits, dst, size) 61 * convert IPv4 network number from network to presentation format. 62 * generates CIDR style result always. 63 * return: 64 * pointer to dst, or NULL if an error occurred (check errno). 65 * note: 66 * network byte order assumed. this means 192.5.5.240/28 has 67 * 0x11110000 in its fourth octet. 68 * author: 69 * Paul Vixie (ISC), July 1996 70 */ 71 static char * 72 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size) 73 { 74 char *odst = dst; 75 u_int m; 76 int b; 77 char *ep; 78 int advance; 79 80 ep = dst + size; 81 if (ep <= dst) 82 goto emsgsize; 83 84 if (bits < 0 || bits > 32) { 85 errno = EINVAL; 86 return (NULL); 87 } 88 if (bits == 0) { 89 if (ep - dst < sizeof "0") 90 goto emsgsize; 91 *dst++ = '0'; 92 *dst = '\0'; 93 } 94 95 /* Format whole octets. */ 96 for (b = bits / 8; b > 0; b--) { 97 if (ep - dst < sizeof "255.") 98 goto emsgsize; 99 advance = snprintf(dst, ep - dst, "%u", *src++); 100 if (advance <= 0 || advance >= ep - dst) 101 goto emsgsize; 102 dst += advance; 103 if (b > 1) { 104 if (dst + 1 >= ep) 105 goto emsgsize; 106 *dst++ = '.'; 107 *dst = '\0'; 108 } 109 } 110 111 /* Format partial octet. */ 112 b = bits % 8; 113 if (b > 0) { 114 if (ep - dst < sizeof ".255") 115 goto emsgsize; 116 if (dst != odst) 117 if (dst + 1 >= ep) 118 goto emsgsize; 119 *dst++ = '.'; 120 m = ((1 << b) - 1) << (8 - b); 121 advance = snprintf(dst, ep - dst, "%u", *src & m); 122 if (advance <= 0 || advance >= ep - dst) 123 goto emsgsize; 124 dst += advance; 125 } 126 127 /* Format CIDR /width. */ 128 if (ep - dst < sizeof "/32") 129 goto emsgsize; 130 advance = snprintf(dst, ep - dst, "/%u", bits); 131 if (advance <= 0 || advance >= ep - dst) 132 goto emsgsize; 133 dst += advance; 134 return (odst); 135 136 emsgsize: 137 errno = EMSGSIZE; 138 return (NULL); 139 } 140 141 static char * 142 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size) 143 { 144 int ret; 145 char buf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255:255:255:255/128")]; 146 147 if (bits < 0 || bits > 128) { 148 errno = EINVAL; 149 return (NULL); 150 } 151 152 if (inet_ntop(AF_INET6, src, buf, size) == NULL) 153 return (NULL); 154 155 ret = snprintf(dst, size, "%s/%d", buf, bits); 156 if (ret == -1 || ret >= size) { 157 errno = EMSGSIZE; 158 return (NULL); 159 } 160 161 return (dst); 162 } 163