1 /* $OpenBSD: inet_net_ntop.c,v 1.9 2019/07/03 03:24:04 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
5 * Copyright (c) 1996 by Internet Software Consortium.
6 *
7 * SPDX-License-Identifier: ISC
8 *
9 * Permission to use, copy, modify, and distribute this software for any
10 * purpose with or without fee is hereby granted, provided that the above
11 * copyright notice and this permission notice appear in all copies.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
14 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
16 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
17 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
18 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
19 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
20 * SOFTWARE.
21 */
22
23 #include "port_before.h"
24
25 #include <sys/types.h>
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
29
30 #include <errno.h>
31 #include <stdio.h>
32 #include <string.h>
33 #include <stdlib.h>
34
35 #include "port_after.h"
36
37 static char *inet_net_ntop_ipv4(const u_char *, int, char *, size_t);
38 static char *inet_net_ntop_ipv6(const u_char *, int, char *, size_t);
39
40 /*
41 * char *
42 * inet_net_ntop(af, src, bits, dst, size)
43 * convert network number from network to presentation format.
44 * generates CIDR style result always.
45 * return:
46 * pointer to dst, or NULL if an error occurred (check errno).
47 * author:
48 * Paul Vixie (ISC), July 1996
49 */
50 char *
inet_net_ntop(int af,const void * src,int bits,char * dst,size_t size)51 inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)
52 {
53 switch (af) {
54 case AF_INET:
55 return (inet_net_ntop_ipv4(src, bits, dst, size));
56 case AF_INET6:
57 return (inet_net_ntop_ipv6(src, bits, dst, size));
58 default:
59 errno = EAFNOSUPPORT;
60 return (NULL);
61 }
62 }
63
64 /*
65 * static char *
66 * inet_net_ntop_ipv4(src, bits, dst, size)
67 * convert IPv4 network number from network to presentation format.
68 * generates CIDR style result always.
69 * return:
70 * pointer to dst, or NULL if an error occurred (check errno).
71 * note:
72 * network byte order assumed. this means 192.5.5.240/28 has
73 * 0b11110000 in its fourth octet.
74 * author:
75 * Paul Vixie (ISC), July 1996
76 */
77 static char *
inet_net_ntop_ipv4(const u_char * src,int bits,char * dst,size_t size)78 inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
79 {
80 char *odst = dst;
81 u_int m;
82 int b;
83 char *ep;
84 int advance;
85
86 ep = dst + size;
87 if (ep <= dst)
88 goto emsgsize;
89
90 if (bits < 0 || bits > 32) {
91 errno = EINVAL;
92 return (NULL);
93 }
94 if (bits == 0) {
95 if (ep - dst < sizeof "0")
96 goto emsgsize;
97 *dst++ = '0';
98 *dst = '\0';
99 }
100
101 /* Format whole octets. */
102 for (b = bits / 8; b > 0; b--) {
103 if (ep - dst < sizeof "255.")
104 goto emsgsize;
105 advance = snprintf(dst, ep - dst, "%u", *src++);
106 if (advance <= 0 || advance >= ep - dst)
107 goto emsgsize;
108 dst += advance;
109 if (b > 1) {
110 if (dst + 1 >= ep)
111 goto emsgsize;
112 *dst++ = '.';
113 *dst = '\0';
114 }
115 }
116
117 /* Format partial octet. */
118 b = bits % 8;
119 if (b > 0) {
120 if (ep - dst < sizeof ".255")
121 goto emsgsize;
122 if (dst != odst)
123 *dst++ = '.';
124 m = ((1 << b) - 1) << (8 - b);
125 advance = snprintf(dst, ep - dst, "%u", *src & m);
126 if (advance <= 0 || advance >= ep - dst)
127 goto emsgsize;
128 dst += advance;
129 }
130
131 /* Format CIDR /width. */
132 if (ep - dst < sizeof "/32")
133 goto emsgsize;
134 advance = snprintf(dst, ep - dst, "/%u", bits);
135 if (advance <= 0 || advance >= ep - dst)
136 goto emsgsize;
137 dst += advance;
138 return (odst);
139
140 emsgsize:
141 errno = EMSGSIZE;
142 return (NULL);
143 }
144
145 static char *
inet_net_ntop_ipv6(const u_char * src,int bits,char * dst,size_t size)146 inet_net_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
147 {
148 int ret;
149 char buf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255:255:255:255/128")];
150
151 if (bits < 0 || bits > 128) {
152 errno = EINVAL;
153 return (NULL);
154 }
155
156 if (inet_ntop(AF_INET6, src, buf, size) == NULL)
157 return (NULL);
158
159 ret = snprintf(dst, size, "%s/%d", buf, bits);
160 if (ret < 0 || ret >= size) {
161 errno = EMSGSIZE;
162 return (NULL);
163 }
164
165 return (dst);
166 }
167
168 /*
169 * Weak aliases for applications that use certain private entry points,
170 * and fail to include <arpa/inet.h>.
171 */
172 #undef inet_net_ntop
173 __weak_reference(__inet_net_ntop, inet_net_ntop);
174