1 /*
2 * Copyright (C) 1996-2022 Internet Software Consortium.
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
9 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
10 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
11 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
13 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
14 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
15 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 *
17 * SPDX-License-Identifier: ISC
18 */
19 /*
20 * Original code by Paul Vixie. "curlified" by Gisle Vanem.
21 */
22
23 #include "curl_setup.h"
24
25 #ifndef HAVE_INET_NTOP
26
27 #ifdef HAVE_SYS_PARAM_H
28 #include <sys/param.h>
29 #endif
30 #ifdef HAVE_NETINET_IN_H
31 #include <netinet/in.h>
32 #endif
33 #ifdef HAVE_ARPA_INET_H
34 #include <arpa/inet.h>
35 #endif
36
37 #include "inet_ntop.h"
38 #include "curl_printf.h"
39
40 #define IN6ADDRSZ 16
41 #define INADDRSZ 4
42 #define INT16SZ 2
43
44 /*
45 * If USE_IPV6 is disabled, we still want to parse IPv6 addresses, so make
46 * sure we have _some_ value for AF_INET6 without polluting our fake value
47 * everywhere.
48 */
49 #if !defined(USE_IPV6) && !defined(AF_INET6)
50 #define AF_INET6 (AF_INET + 1)
51 #endif
52
53 /*
54 * Format an IPv4 address, more or less like inet_ntop().
55 *
56 * Returns `dst' (as a const)
57 * Note:
58 * - uses no statics
59 * - takes a unsigned char* not an in_addr as input
60 */
inet_ntop4(const unsigned char * src,char * dst,size_t size)61 static char *inet_ntop4 (const unsigned char *src, char *dst, size_t size)
62 {
63 char tmp[sizeof("255.255.255.255")];
64 size_t len;
65
66 DEBUGASSERT(size >= 16);
67
68 tmp[0] = '\0';
69 (void)msnprintf(tmp, sizeof(tmp), "%d.%d.%d.%d",
70 ((int)((unsigned char)src[0])) & 0xff,
71 ((int)((unsigned char)src[1])) & 0xff,
72 ((int)((unsigned char)src[2])) & 0xff,
73 ((int)((unsigned char)src[3])) & 0xff);
74
75 len = strlen(tmp);
76 if(len == 0 || len >= size) {
77 errno = ENOSPC;
78 return (NULL);
79 }
80 strcpy(dst, tmp);
81 return dst;
82 }
83
84 /*
85 * Convert IPv6 binary address into presentation (printable) format.
86 */
inet_ntop6(const unsigned char * src,char * dst,size_t size)87 static char *inet_ntop6 (const unsigned char *src, char *dst, size_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")];
97 char *tp;
98 struct {
99 int base;
100 int len;
101 } best, cur;
102 unsigned int words[IN6ADDRSZ / INT16SZ];
103 int i;
104
105 /* Preprocess:
106 * Copy the input (bytewise) array into a wordwise array.
107 * Find the longest run of 0x00's in src[] for :: shorthanding.
108 */
109 memset(words, '\0', sizeof(words));
110 for(i = 0; i < IN6ADDRSZ; i++)
111 words[i/2] |= ((unsigned int)src[i] << ((1 - (i % 2)) << 3));
112
113 best.base = -1;
114 cur.base = -1;
115 best.len = 0;
116 cur.len = 0;
117
118 for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
119 if(words[i] == 0) {
120 if(cur.base == -1) {
121 cur.base = i; cur.len = 1;
122 }
123 else
124 cur.len++;
125 }
126 else if(cur.base != -1) {
127 if(best.base == -1 || cur.len > best.len)
128 best = cur;
129 cur.base = -1;
130 }
131 }
132 if((cur.base != -1) && (best.base == -1 || cur.len > best.len))
133 best = cur;
134 if(best.base != -1 && best.len < 2)
135 best.base = -1;
136 /* Format the result. */
137 tp = tmp;
138 for(i = 0; i < (IN6ADDRSZ / INT16SZ); i++) {
139 /* Are we inside the best run of 0x00's? */
140 if(best.base != -1 && i >= best.base && i < (best.base + best.len)) {
141 if(i == best.base)
142 *tp++ = ':';
143 continue;
144 }
145
146 /* Are we following an initial run of 0x00s or any real hex?
147 */
148 if(i)
149 *tp++ = ':';
150
151 /* Is this address an encapsulated IPv4?
152 */
153 if(i == 6 && best.base == 0 &&
154 (best.len == 6 || (best.len == 5 && words[5] == 0xffff))) {
155 if(!inet_ntop4(src + 12, tp, sizeof(tmp) - (tp - tmp))) {
156 errno = ENOSPC;
157 return (NULL);
158 }
159 tp += strlen(tp);
160 break;
161 }
162 tp += msnprintf(tp, 5, "%x", words[i]);
163 }
164
165 /* Was it a trailing run of 0x00's?
166 */
167 if(best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
168 *tp++ = ':';
169 *tp++ = '\0';
170
171 /* Check for overflow, copy, and we're done.
172 */
173 if((size_t)(tp - tmp) > size) {
174 errno = ENOSPC;
175 return (NULL);
176 }
177 strcpy(dst, tmp);
178 return dst;
179 }
180
181 /*
182 * Convert a network format address to presentation format.
183 *
184 * Returns pointer to presentation format address (`buf').
185 * Returns NULL on error and errno set with the specific
186 * error, EAFNOSUPPORT or ENOSPC.
187 *
188 * On Windows we store the error in the thread errno, not
189 * in the winsock error code. This is to avoid losing the
190 * actual last winsock error. So when this function returns
191 * NULL, check errno not SOCKERRNO.
192 */
Curl_inet_ntop(int af,const void * src,char * buf,size_t size)193 char *Curl_inet_ntop(int af, const void *src, char *buf, size_t size)
194 {
195 switch(af) {
196 case AF_INET:
197 return inet_ntop4((const unsigned char *)src, buf, size);
198 case AF_INET6:
199 return inet_ntop6((const unsigned char *)src, buf, size);
200 default:
201 errno = EAFNOSUPPORT;
202 return NULL;
203 }
204 }
205 #endif /* HAVE_INET_NTOP */
206
