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  *	  src/backend/utils/adt/inet_cidr_ntop.c
18  */
19 
20 #if defined(LIBC_SCCS) && !defined(lint)
21 static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.2 2004/03/09 09:17:27 marka Exp $";
22 #endif
23 
24 #include "postgres.h"
25 
26 #include <sys/socket.h>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
29 
30 #include "utils/builtins.h"
31 #include "utils/inet.h"
32 
33 
34 #ifdef SPRINTF_CHAR
35 #define SPRINTF(x) strlen(sprintf/**/x)
36 #else
37 #define SPRINTF(x) ((size_t)sprintf x)
38 #endif
39 
40 static char *inet_cidr_ntop_ipv4(const u_char *src, int bits,
41 					char *dst, size_t size);
42 static char *inet_cidr_ntop_ipv6(const u_char *src, int bits,
43 					char *dst, size_t size);
44 
45 /*
46  * char *
47  * inet_cidr_ntop(af, src, bits, dst, size)
48  *	convert network number from network to presentation format.
49  *	generates CIDR style result always.
50  * return:
51  *	pointer to dst, or NULL if an error occurred (check errno).
52  * author:
53  *	Paul Vixie (ISC), July 1996
54  */
55 char *
inet_cidr_ntop(int af,const void * src,int bits,char * dst,size_t size)56 inet_cidr_ntop(int af, const void *src, int bits, char *dst, size_t size)
57 {
58 	switch (af)
59 	{
60 		case PGSQL_AF_INET:
61 			return inet_cidr_ntop_ipv4(src, bits, dst, size);
62 		case PGSQL_AF_INET6:
63 			return inet_cidr_ntop_ipv6(src, bits, dst, size);
64 		default:
65 			errno = EAFNOSUPPORT;
66 			return NULL;
67 	}
68 }
69 
70 
71 /*
72  * static char *
73  * inet_cidr_ntop_ipv4(src, bits, dst, size)
74  *	convert IPv4 network number from network to presentation format.
75  *	generates CIDR style result always.
76  * return:
77  *	pointer to dst, or NULL if an error occurred (check errno).
78  * note:
79  *	network byte order assumed.  this means 192.5.5.240/28 has
80  *	0b11110000 in its fourth octet.
81  * author:
82  *	Paul Vixie (ISC), July 1996
83  */
84 static char *
inet_cidr_ntop_ipv4(const u_char * src,int bits,char * dst,size_t size)85 inet_cidr_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)
86 {
87 	char	   *odst = dst;
88 	char	   *t;
89 	u_int		m;
90 	int			b;
91 
92 	if (bits < 0 || bits > 32)
93 	{
94 		errno = EINVAL;
95 		return NULL;
96 	}
97 
98 	if (bits == 0)
99 	{
100 		if (size < sizeof "0")
101 			goto emsgsize;
102 		*dst++ = '0';
103 		size--;
104 		*dst = '\0';
105 	}
106 
107 	/* Format whole octets. */
108 	for (b = bits / 8; b > 0; b--)
109 	{
110 		if (size <= sizeof "255.")
111 			goto emsgsize;
112 		t = dst;
113 		dst += SPRINTF((dst, "%u", *src++));
114 		if (b > 1)
115 		{
116 			*dst++ = '.';
117 			*dst = '\0';
118 		}
119 		size -= (size_t) (dst - t);
120 	}
121 
122 	/* Format partial octet. */
123 	b = bits % 8;
124 	if (b > 0)
125 	{
126 		if (size <= sizeof ".255")
127 			goto emsgsize;
128 		t = dst;
129 		if (dst != odst)
130 			*dst++ = '.';
131 		m = ((1 << b) - 1) << (8 - b);
132 		dst += SPRINTF((dst, "%u", *src & m));
133 		size -= (size_t) (dst - t);
134 	}
135 
136 	/* Format CIDR /width. */
137 	if (size <= sizeof "/32")
138 		goto emsgsize;
139 	dst += SPRINTF((dst, "/%u", bits));
140 	return odst;
141 
142 emsgsize:
143 	errno = EMSGSIZE;
144 	return NULL;
145 }
146 
147 /*
148  * static char *
149  * inet_cidr_ntop_ipv6(src, bits, fakebits, dst, size)
150  *	convert IPv6 network number from network to presentation format.
151  *	generates CIDR style result always. Picks the shortest representation
152  *	unless the IP is really IPv4.
153  *	always prints specified number of bits (bits).
154  * return:
155  *	pointer to dst, or NULL if an error occurred (check errno).
156  * note:
157  *	network byte order assumed.  this means 192.5.5.240/28 has
158  *	0x11110000 in its fourth octet.
159  * author:
160  *	Vadim Kogan (UCB), June 2001
161  *	Original version (IPv4) by Paul Vixie (ISC), July 1996
162  */
163 
164 static char *
inet_cidr_ntop_ipv6(const u_char * src,int bits,char * dst,size_t size)165 inet_cidr_ntop_ipv6(const u_char *src, int bits, char *dst, size_t size)
166 {
167 	u_int		m;
168 	int			b;
169 	int			p;
170 	int			zero_s,
171 				zero_l,
172 				tmp_zero_s,
173 				tmp_zero_l;
174 	int			i;
175 	int			is_ipv4 = 0;
176 	unsigned char inbuf[16];
177 	char		outbuf[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255/128")];
178 	char	   *cp;
179 	int			words;
180 	u_char	   *s;
181 
182 	if (bits < 0 || bits > 128)
183 	{
184 		errno = EINVAL;
185 		return NULL;
186 	}
187 
188 	cp = outbuf;
189 
190 	if (bits == 0)
191 	{
192 		*cp++ = ':';
193 		*cp++ = ':';
194 		*cp = '\0';
195 	}
196 	else
197 	{
198 		/* Copy src to private buffer.  Zero host part. */
199 		p = (bits + 7) / 8;
200 		memcpy(inbuf, src, p);
201 		memset(inbuf + p, 0, 16 - p);
202 		b = bits % 8;
203 		if (b != 0)
204 		{
205 			m = ((u_int) ~0) << (8 - b);
206 			inbuf[p - 1] &= m;
207 		}
208 
209 		s = inbuf;
210 
211 		/* how many words need to be displayed in output */
212 		words = (bits + 15) / 16;
213 		if (words == 1)
214 			words = 2;
215 
216 		/* Find the longest substring of zero's */
217 		zero_s = zero_l = tmp_zero_s = tmp_zero_l = 0;
218 		for (i = 0; i < (words * 2); i += 2)
219 		{
220 			if ((s[i] | s[i + 1]) == 0)
221 			{
222 				if (tmp_zero_l == 0)
223 					tmp_zero_s = i / 2;
224 				tmp_zero_l++;
225 			}
226 			else
227 			{
228 				if (tmp_zero_l && zero_l < tmp_zero_l)
229 				{
230 					zero_s = tmp_zero_s;
231 					zero_l = tmp_zero_l;
232 					tmp_zero_l = 0;
233 				}
234 			}
235 		}
236 
237 		if (tmp_zero_l && zero_l < tmp_zero_l)
238 		{
239 			zero_s = tmp_zero_s;
240 			zero_l = tmp_zero_l;
241 		}
242 
243 		if (zero_l != words && zero_s == 0 && ((zero_l == 6) ||
244 											   ((zero_l == 5 && s[10] == 0xff && s[11] == 0xff) ||
245 												((zero_l == 7 && s[14] != 0 && s[15] != 1)))))
246 			is_ipv4 = 1;
247 
248 		/* Format whole words. */
249 		for (p = 0; p < words; p++)
250 		{
251 			if (zero_l != 0 && p >= zero_s && p < zero_s + zero_l)
252 			{
253 				/* Time to skip some zeros */
254 				if (p == zero_s)
255 					*cp++ = ':';
256 				if (p == words - 1)
257 					*cp++ = ':';
258 				s++;
259 				s++;
260 				continue;
261 			}
262 
263 			if (is_ipv4 && p > 5)
264 			{
265 				*cp++ = (p == 6) ? ':' : '.';
266 				cp += SPRINTF((cp, "%u", *s++));
267 				/* we can potentially drop the last octet */
268 				if (p != 7 || bits > 120)
269 				{
270 					*cp++ = '.';
271 					cp += SPRINTF((cp, "%u", *s++));
272 				}
273 			}
274 			else
275 			{
276 				if (cp != outbuf)
277 					*cp++ = ':';
278 				cp += SPRINTF((cp, "%x", *s * 256 + s[1]));
279 				s += 2;
280 			}
281 		}
282 	}
283 	/* Format CIDR /width. */
284 	(void) SPRINTF((cp, "/%u", bits));
285 	if (strlen(outbuf) + 1 > size)
286 		goto emsgsize;
287 	strcpy(dst, outbuf);
288 
289 	return dst;
290 
291 emsgsize:
292 	errno = EMSGSIZE;
293 	return NULL;
294 }
295