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prefix.c revision 1.3 
      1 /*	$NetBSD: prefix.c,v 1.3 2001/11/21 06:52:35 itojun Exp $	*/
      2 /*	$KAME: prefix.c,v 1.9 2001/07/02 14:36:49 itojun 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 #ifdef NI_WITHSCOPEID
     59 const int niflags = NI_NUMERICHOST | NI_WITHSCOPEID;
     60 #else
     61 const int niflags = NI_NUMERICHOST;
     62 #endif
     63 
     64 static int
     65 prefix_set(s, prefix, slash)
     66 	const char *s;
     67 	struct prefix *prefix;
     68 	int slash;
     69 {
     70 	char *p = NULL, *q, *r;
     71 	struct addrinfo hints, *res = NULL;
     72 	int max;
     73 	char *a;
     74 
     75 	p = strdup(s);
     76 	if (!p)
     77 		goto fail;
     78 	q = strchr(p, '/');
     79 	if (q) {
     80 		if (!slash)
     81 			goto fail;
     82 		*q++ = '\0';
     83 	}
     84 
     85 	memset(&hints, 0, sizeof(hints));
     86 	hints.ai_family = PF_UNSPEC;
     87 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
     88 	hints.ai_flags = AI_NUMERICHOST;
     89 	if (getaddrinfo(p, "0", &hints, &res))
     90 		goto fail;
     91 	if (res->ai_next || res->ai_addrlen > sizeof(prefix->a))
     92 		goto fail;
     93 	memcpy(&prefix->a, res->ai_addr, res->ai_addrlen);
     94 
     95 	switch (prefix->a.ss_family) {
     96 	case AF_INET:
     97 		max = 32;
     98 		a = (char *)&((struct sockaddr_in *)&prefix->a)->sin_addr;
     99 		break;
    100 	case AF_INET6:
    101 		max = 128;
    102 		a = (char *)&((struct sockaddr_in6 *)&prefix->a)->sin6_addr;
    103 		break;
    104 	default:
    105 		a = NULL;
    106 		max = -1;
    107 		break;
    108 	}
    109 
    110 	if (q) {
    111 		r = NULL;
    112 		prefix->l = (int)strtoul(q, &r, 10);
    113 		if (!*q || *r)
    114 			goto fail;
    115 		if (prefix->l < 0 || prefix->l > max)
    116 			goto fail;
    117 	} else
    118 		prefix->l = max;
    119 
    120 	if (p)
    121 		free(p);
    122 	if (res)
    123 		freeaddrinfo(res);
    124 	return 0;
    125 
    126 fail:
    127 	if (p)
    128 		free(p);
    129 	if (res)
    130 		freeaddrinfo(res);
    131 	return -1;
    132 }
    133 
    134 const char *
    135 prefix_string(prefix)
    136 	const struct prefix *prefix;
    137 {
    138 	static char buf[NI_MAXHOST + 20];
    139 	char hbuf[NI_MAXHOST];
    140 
    141 	if (getnameinfo((const struct sockaddr *)&prefix->a, prefix->a.ss_len,
    142 	    hbuf, sizeof(hbuf), NULL, 0, niflags))
    143 		return NULL;
    144 	snprintf(buf, sizeof(buf), "%s/%d", hbuf, prefix->l);
    145 	return buf;
    146 }
    147 
    148 int
    149 prefix_match(prefix, sa)
    150 	const struct prefix *prefix;
    151 	const struct sockaddr *sa;
    152 {
    153 	struct sockaddr_storage a, b;
    154 	char *pa, *pb;
    155 	int off, l;
    156 
    157 	if (prefix->a.ss_family != sa->sa_family ||
    158 	    prefix->a.ss_len != sa->sa_len)
    159 		return 0;
    160 
    161 	if (prefix->a.ss_len > sizeof(a) || sa->sa_len > sizeof(b))
    162 		return 0;
    163 
    164 	switch (prefix->a.ss_family) {
    165 	case AF_INET:
    166 		off = offsetof(struct sockaddr_in, sin_addr);
    167 		break;
    168 	case AF_INET6:
    169 		off = offsetof(struct sockaddr_in6, sin6_addr);
    170 		break;
    171 	default:
    172 		if (memcmp(&prefix->a, sa, prefix->a.ss_len) != 0)
    173 			return 0;
    174 		else
    175 			return 1;
    176 	}
    177 
    178 	memcpy(&a, &prefix->a, prefix->a.ss_len);
    179 	memcpy(&b, sa, sa->sa_len);
    180 	l = prefix->l / 8 + (prefix->l % 8 ? 1 : 0);
    181 
    182 	/* overrun check */
    183 	if (off + l > a.ss_len)
    184 		return 0;
    185 
    186 	pa = ((char *)&a) + off;
    187 	pb = ((char *)&b) + off;
    188 	if (prefix->l % 8) {
    189 		pa[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    190 		pb[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    191 	}
    192 	if (memcmp(pa, pb, l) != 0)
    193 		return 0;
    194 	else
    195 		return 1;
    196 }
    197 
    198 /*
    199  * prefix/prefixlen permit/deny prefix/prefixlen [srcaddr]
    200  * 3ffe::/16 permit 10.0.0.0/8 10.1.1.1
    201  */
    202 static struct config *
    203 config_load1(line)
    204 	const char *line;
    205 {
    206 	struct config *conf;
    207 	char buf[BUFSIZ];
    208 	char *p;
    209 	char *token[4];
    210 	int i;
    211 
    212 	if (strlen(line) + 1 > sizeof(buf))
    213 		return NULL;
    214 	strlcpy(buf, line, sizeof(buf));
    215 
    216 	p = strchr(buf, '\n');
    217 	if (!p)
    218 		return NULL;
    219 	*p = '\0';
    220 	p = strchr(buf, '#');
    221 	if (p)
    222 		*p = '\0';
    223 	if (strlen(buf) == 0)
    224 		return NULL;
    225 
    226 	p = buf;
    227 	memset(token, 0, sizeof(token));
    228 	for (i = 0; i < sizeof(token) / sizeof(token[0]); i++) {
    229 		token[i] = strtok(p, "\t ");
    230 		p = NULL;
    231 		if (token[i] == NULL)
    232 			break;
    233 	}
    234 	/* extra tokens? */
    235 	if (strtok(p, "\t ") != NULL)
    236 		return NULL;
    237 	/* insufficient tokens */
    238 	switch (i) {
    239 	case 3:
    240 	case 4:
    241 		break;
    242 	default:
    243 		return NULL;
    244 	}
    245 
    246 	conf = (struct config *)malloc(sizeof(*conf));
    247 	if (conf == NULL)
    248 		return NULL;
    249 	memset(conf, 0, sizeof(*conf));
    250 
    251 	if (strcasecmp(token[1], "permit") == 0)
    252 		conf->permit = 1;
    253 	else if (strcasecmp(token[1], "deny") == 0)
    254 		conf->permit = 0;
    255 	else {
    256 		/* invalid keyword is considered as "deny" */
    257 		conf->permit = 0;
    258 	}
    259 
    260 	if (prefix_set(token[0], &conf->match, 1) < 0)
    261 		goto fail;
    262 	if (prefix_set(token[2], &conf->dest, 1) < 0)
    263 		goto fail;
    264 	if (token[3]) {
    265 		if (prefix_set(token[3], &conf->src, 0) < 0)
    266 			goto fail;
    267 	}
    268 
    269 	return conf;
    270 
    271 fail:
    272 	free(conf);
    273 	return NULL;
    274 }
    275 
    276 int
    277 config_load(configfile)
    278 	const char *configfile;
    279 {
    280 	FILE *fp;
    281 	char buf[BUFSIZ];
    282 	struct config *conf, *p;
    283 	struct config sentinel;
    284 
    285 	config_list = NULL;
    286 
    287 	if (!configfile)
    288 		configfile = _PATH_PREFIX_CONF;
    289 	fp = fopen(configfile, "r");
    290 	if (fp == NULL)
    291 		return -1;
    292 
    293 	p = &sentinel;
    294 	while (fgets(buf, sizeof(buf), fp) != NULL) {
    295 		conf = config_load1(buf);
    296 		if (conf) {
    297 			p->next = conf;
    298 			p = p->next;
    299 		}
    300 	}
    301 	config_list = sentinel.next;
    302 
    303 	fclose(fp);
    304 	return 0;
    305 }
    306 
    307 #if 0
    308 static void
    309 config_show1(conf)
    310 	const struct config *conf;
    311 {
    312 	const char *p;
    313 
    314 	p = prefix_string(&conf->match);
    315 	printf("%s", p ? p : "?");
    316 
    317 	if (conf->permit)
    318 		printf(" permit");
    319 	else
    320 		printf(" deny");
    321 
    322 	p = prefix_string(&conf->dest);
    323 	printf(" %s", p ? p : "?");
    324 
    325 	printf("\n");
    326 }
    327 
    328 static void
    329 config_show()
    330 {
    331 	struct config *conf;
    332 
    333 	for (conf = config_list; conf; conf = conf->next)
    334 		config_show1(conf);
    335 }
    336 #endif
    337 
    338 const struct config *
    339 config_match(sa1, sa2)
    340 	struct sockaddr *sa1, *sa2;
    341 {
    342 	static struct config conf;
    343 	const struct config *p;
    344 
    345 	if (sa1->sa_len > sizeof(conf.match.a) ||
    346 	    sa2->sa_len > sizeof(conf.dest.a))
    347 		return NULL;
    348 
    349 	memset(&conf, 0, sizeof(conf));
    350 	if (!config_list) {
    351 		conf.permit = 1;
    352 		memcpy(&conf.match.a, sa1, sa1->sa_len);
    353 		memcpy(&conf.dest.a, sa2, sa2->sa_len);
    354 		return &conf;
    355 	}
    356 
    357 	for (p = config_list; p; p = p->next)
    358 		if (prefix_match(&p->match, sa1) && prefix_match(&p->dest, sa2))
    359 			return p;
    360 
    361 	return NULL;
    362 }
    363