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prefix.c revision 1.4 
      1 /*	$NetBSD: prefix.c,v 1.4 2002/06/07 00:20:45 itojun Exp $	*/
      2 /*	$KAME: prefix.c,v 1.11 2001/11/13 12:38:45 jinmei Exp $	*/
      3 
      4 /*
      5  * Copyright (C) 2000 WIDE Project.
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. Neither the name of the project nor the names of its contributors
     17  *    may be used to endorse or promote products derived from this software
     18  *    without specific prior written permission.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     30  * SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/types.h>
     34 #include <sys/socket.h>
     35 #include <netinet/in.h>
     36 #include <stdio.h>
     37 #include <netdb.h>
     38 #include <string.h>
     39 #include <stddef.h>
     40 #include <stdlib.h>
     41 #include <limits.h>
     42 
     43 #ifndef offsetof
     44 #define	offsetof(type, member)	((size_t)(u_long)(&((type *)0)->member))
     45 #endif
     46 
     47 #include "faithd.h"
     48 #include "prefix.h"
     49 
     50 static int prefix_set __P((const char *, struct prefix *, int));
     51 static struct config *config_load1 __P((const char *));
     52 #if 0
     53 static void config_show1 __P((const struct config *));
     54 static void config_show __P((void));
     55 #endif
     56 
     57 struct config *config_list = NULL;
     58 const int niflags = NI_NUMERICHOST;
     59 
     60 static int
     61 prefix_set(s, prefix, slash)
     62 	const char *s;
     63 	struct prefix *prefix;
     64 	int slash;
     65 {
     66 	char *p = NULL, *q, *r;
     67 	struct addrinfo hints, *res = NULL;
     68 	int max;
     69 	char *a;
     70 
     71 	p = strdup(s);
     72 	if (!p)
     73 		goto fail;
     74 	q = strchr(p, '/');
     75 	if (q) {
     76 		if (!slash)
     77 			goto fail;
     78 		*q++ = '\0';
     79 	}
     80 
     81 	memset(&hints, 0, sizeof(hints));
     82 	hints.ai_family = PF_UNSPEC;
     83 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
     84 	hints.ai_flags = AI_NUMERICHOST;
     85 	if (getaddrinfo(p, "0", &hints, &res))
     86 		goto fail;
     87 	if (res->ai_next || res->ai_addrlen > sizeof(prefix->a))
     88 		goto fail;
     89 	memcpy(&prefix->a, res->ai_addr, res->ai_addrlen);
     90 
     91 	switch (prefix->a.ss_family) {
     92 	case AF_INET:
     93 		max = 32;
     94 		a = (char *)&((struct sockaddr_in *)&prefix->a)->sin_addr;
     95 		break;
     96 	case AF_INET6:
     97 		max = 128;
     98 		a = (char *)&((struct sockaddr_in6 *)&prefix->a)->sin6_addr;
     99 		break;
    100 	default:
    101 		a = NULL;
    102 		max = -1;
    103 		break;
    104 	}
    105 
    106 	if (q) {
    107 		r = NULL;
    108 		prefix->l = (int)strtoul(q, &r, 10);
    109 		if (!*q || *r)
    110 			goto fail;
    111 		if (prefix->l < 0 || prefix->l > max)
    112 			goto fail;
    113 	} else
    114 		prefix->l = max;
    115 
    116 	if (p)
    117 		free(p);
    118 	if (res)
    119 		freeaddrinfo(res);
    120 	return 0;
    121 
    122 fail:
    123 	if (p)
    124 		free(p);
    125 	if (res)
    126 		freeaddrinfo(res);
    127 	return -1;
    128 }
    129 
    130 const char *
    131 prefix_string(prefix)
    132 	const struct prefix *prefix;
    133 {
    134 	static char buf[NI_MAXHOST + 20];
    135 	char hbuf[NI_MAXHOST];
    136 
    137 	if (getnameinfo((const struct sockaddr *)&prefix->a, prefix->a.ss_len,
    138 	    hbuf, sizeof(hbuf), NULL, 0, niflags))
    139 		return NULL;
    140 	snprintf(buf, sizeof(buf), "%s/%d", hbuf, prefix->l);
    141 	return buf;
    142 }
    143 
    144 int
    145 prefix_match(prefix, sa)
    146 	const struct prefix *prefix;
    147 	const struct sockaddr *sa;
    148 {
    149 	struct sockaddr_storage a, b;
    150 	char *pa, *pb;
    151 	int off, l;
    152 
    153 	if (prefix->a.ss_family != sa->sa_family ||
    154 	    prefix->a.ss_len != sa->sa_len)
    155 		return 0;
    156 
    157 	if (prefix->a.ss_len > sizeof(a) || sa->sa_len > sizeof(b))
    158 		return 0;
    159 
    160 	switch (prefix->a.ss_family) {
    161 	case AF_INET:
    162 		off = offsetof(struct sockaddr_in, sin_addr);
    163 		break;
    164 	case AF_INET6:
    165 		off = offsetof(struct sockaddr_in6, sin6_addr);
    166 		break;
    167 	default:
    168 		if (memcmp(&prefix->a, sa, prefix->a.ss_len) != 0)
    169 			return 0;
    170 		else
    171 			return 1;
    172 	}
    173 
    174 	memcpy(&a, &prefix->a, prefix->a.ss_len);
    175 	memcpy(&b, sa, sa->sa_len);
    176 	l = prefix->l / 8 + (prefix->l % 8 ? 1 : 0);
    177 
    178 	/* overrun check */
    179 	if (off + l > a.ss_len)
    180 		return 0;
    181 
    182 	pa = ((char *)&a) + off;
    183 	pb = ((char *)&b) + off;
    184 	if (prefix->l % 8) {
    185 		pa[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    186 		pb[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    187 	}
    188 	if (memcmp(pa, pb, l) != 0)
    189 		return 0;
    190 	else
    191 		return 1;
    192 }
    193 
    194 /*
    195  * prefix/prefixlen permit/deny prefix/prefixlen [srcaddr]
    196  * 3ffe::/16 permit 10.0.0.0/8 10.1.1.1
    197  */
    198 static struct config *
    199 config_load1(line)
    200 	const char *line;
    201 {
    202 	struct config *conf;
    203 	char buf[BUFSIZ];
    204 	char *p;
    205 	char *token[4];
    206 	int i;
    207 
    208 	if (strlen(line) + 1 > sizeof(buf))
    209 		return NULL;
    210 	strlcpy(buf, line, sizeof(buf));
    211 
    212 	p = strchr(buf, '\n');
    213 	if (!p)
    214 		return NULL;
    215 	*p = '\0';
    216 	p = strchr(buf, '#');
    217 	if (p)
    218 		*p = '\0';
    219 	if (strlen(buf) == 0)
    220 		return NULL;
    221 
    222 	p = buf;
    223 	memset(token, 0, sizeof(token));
    224 	for (i = 0; i < sizeof(token) / sizeof(token[0]); i++) {
    225 		token[i] = strtok(p, "\t ");
    226 		p = NULL;
    227 		if (token[i] == NULL)
    228 			break;
    229 	}
    230 	/* extra tokens? */
    231 	if (strtok(p, "\t ") != NULL)
    232 		return NULL;
    233 	/* insufficient tokens */
    234 	switch (i) {
    235 	case 3:
    236 	case 4:
    237 		break;
    238 	default:
    239 		return NULL;
    240 	}
    241 
    242 	conf = (struct config *)malloc(sizeof(*conf));
    243 	if (conf == NULL)
    244 		return NULL;
    245 	memset(conf, 0, sizeof(*conf));
    246 
    247 	if (strcasecmp(token[1], "permit") == 0)
    248 		conf->permit = 1;
    249 	else if (strcasecmp(token[1], "deny") == 0)
    250 		conf->permit = 0;
    251 	else {
    252 		/* invalid keyword is considered as "deny" */
    253 		conf->permit = 0;
    254 	}
    255 
    256 	if (prefix_set(token[0], &conf->match, 1) < 0)
    257 		goto fail;
    258 	if (prefix_set(token[2], &conf->dest, 1) < 0)
    259 		goto fail;
    260 	if (token[3]) {
    261 		if (prefix_set(token[3], &conf->src, 0) < 0)
    262 			goto fail;
    263 	}
    264 
    265 	return conf;
    266 
    267 fail:
    268 	free(conf);
    269 	return NULL;
    270 }
    271 
    272 int
    273 config_load(configfile)
    274 	const char *configfile;
    275 {
    276 	FILE *fp;
    277 	char buf[BUFSIZ];
    278 	struct config *conf, *p;
    279 	struct config sentinel;
    280 
    281 	config_list = NULL;
    282 
    283 	if (!configfile)
    284 		configfile = _PATH_PREFIX_CONF;
    285 	fp = fopen(configfile, "r");
    286 	if (fp == NULL)
    287 		return -1;
    288 
    289 	p = &sentinel;
    290 	while (fgets(buf, sizeof(buf), fp) != NULL) {
    291 		conf = config_load1(buf);
    292 		if (conf) {
    293 			p->next = conf;
    294 			p = p->next;
    295 		}
    296 	}
    297 	config_list = sentinel.next;
    298 
    299 	fclose(fp);
    300 	return 0;
    301 }
    302 
    303 #if 0
    304 static void
    305 config_show1(conf)
    306 	const struct config *conf;
    307 {
    308 	const char *p;
    309 
    310 	p = prefix_string(&conf->match);
    311 	printf("%s", p ? p : "?");
    312 
    313 	if (conf->permit)
    314 		printf(" permit");
    315 	else
    316 		printf(" deny");
    317 
    318 	p = prefix_string(&conf->dest);
    319 	printf(" %s", p ? p : "?");
    320 
    321 	printf("\n");
    322 }
    323 
    324 static void
    325 config_show()
    326 {
    327 	struct config *conf;
    328 
    329 	for (conf = config_list; conf; conf = conf->next)
    330 		config_show1(conf);
    331 }
    332 #endif
    333 
    334 const struct config *
    335 config_match(sa1, sa2)
    336 	struct sockaddr *sa1, *sa2;
    337 {
    338 	static struct config conf;
    339 	const struct config *p;
    340 
    341 	if (sa1->sa_len > sizeof(conf.match.a) ||
    342 	    sa2->sa_len > sizeof(conf.dest.a))
    343 		return NULL;
    344 
    345 	memset(&conf, 0, sizeof(conf));
    346 	if (!config_list) {
    347 		conf.permit = 1;
    348 		memcpy(&conf.match.a, sa1, sa1->sa_len);
    349 		memcpy(&conf.dest.a, sa2, sa2->sa_len);
    350 		return &conf;
    351 	}
    352 
    353 	for (p = config_list; p; p = p->next)
    354 		if (prefix_match(&p->match, sa1) && prefix_match(&p->dest, sa2))
    355 			return p;
    356 
    357 	return NULL;
    358 }
    359