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prefix.c revision 1.2 
      1 /*	$NetBSD: prefix.c,v 1.2 2001/09/05 01:22:24 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, *q, *r;
     71 	struct addrinfo hints, *res = NULL;
     72 	int max;
     73 	char *a;
     74 
     75 	p = strdup(s);
     76 	q = strchr(p, '/');
     77 	if (q) {
     78 		if (!slash)
     79 			goto fail;
     80 		*q++ = '\0';
     81 	}
     82 
     83 	memset(&hints, 0, sizeof(hints));
     84 	hints.ai_family = PF_UNSPEC;
     85 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
     86 	hints.ai_flags = AI_NUMERICHOST;
     87 	if (getaddrinfo(p, "0", &hints, &res))
     88 		goto fail;
     89 	if (res->ai_next || res->ai_addrlen > sizeof(prefix->a))
     90 		goto fail;
     91 	memcpy(&prefix->a, res->ai_addr, res->ai_addrlen);
     92 
     93 	switch (prefix->a.ss_family) {
     94 	case AF_INET:
     95 		max = 32;
     96 		a = (char *)&((struct sockaddr_in *)&prefix->a)->sin_addr;
     97 		break;
     98 	case AF_INET6:
     99 		max = 128;
    100 		a = (char *)&((struct sockaddr_in6 *)&prefix->a)->sin6_addr;
    101 		break;
    102 	default:
    103 		a = NULL;
    104 		max = -1;
    105 		break;
    106 	}
    107 
    108 	if (q) {
    109 		r = NULL;
    110 		prefix->l = (int)strtoul(q, &r, 10);
    111 		if (!*q || *r)
    112 			goto fail;
    113 		if (prefix->l < 0 || prefix->l > max)
    114 			goto fail;
    115 	} else
    116 		prefix->l = max;
    117 
    118 	if (p)
    119 		free(p);
    120 	if (res)
    121 		freeaddrinfo(res);
    122 	return 0;
    123 
    124 fail:
    125 	if (p)
    126 		free(p);
    127 	if (res)
    128 		freeaddrinfo(res);
    129 	return -1;
    130 }
    131 
    132 const char *
    133 prefix_string(prefix)
    134 	const struct prefix *prefix;
    135 {
    136 	static char buf[NI_MAXHOST + 20];
    137 	char hbuf[NI_MAXHOST];
    138 
    139 	if (getnameinfo((const struct sockaddr *)&prefix->a, prefix->a.ss_len,
    140 	    hbuf, sizeof(hbuf), NULL, 0, niflags))
    141 		return NULL;
    142 	snprintf(buf, sizeof(buf), "%s/%d", hbuf, prefix->l);
    143 	return buf;
    144 }
    145 
    146 int
    147 prefix_match(prefix, sa)
    148 	const struct prefix *prefix;
    149 	const struct sockaddr *sa;
    150 {
    151 	struct sockaddr_storage a, b;
    152 	char *pa, *pb;
    153 	int off, l;
    154 
    155 	if (prefix->a.ss_family != sa->sa_family ||
    156 	    prefix->a.ss_len != sa->sa_len)
    157 		return 0;
    158 
    159 	if (prefix->a.ss_len > sizeof(a) || sa->sa_len > sizeof(b))
    160 		return 0;
    161 
    162 	switch (prefix->a.ss_family) {
    163 	case AF_INET:
    164 		off = offsetof(struct sockaddr_in, sin_addr);
    165 		break;
    166 	case AF_INET6:
    167 		off = offsetof(struct sockaddr_in6, sin6_addr);
    168 		break;
    169 	default:
    170 		if (memcmp(&prefix->a, sa, prefix->a.ss_len) != 0)
    171 			return 0;
    172 		else
    173 			return 1;
    174 	}
    175 
    176 	memcpy(&a, &prefix->a, prefix->a.ss_len);
    177 	memcpy(&b, sa, sa->sa_len);
    178 	l = prefix->l / 8 + (prefix->l % 8 ? 1 : 0);
    179 
    180 	/* overrun check */
    181 	if (off + l > a.ss_len)
    182 		return 0;
    183 
    184 	pa = ((char *)&a) + off;
    185 	pb = ((char *)&b) + off;
    186 	if (prefix->l % 8) {
    187 		pa[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    188 		pb[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
    189 	}
    190 	if (memcmp(pa, pb, l) != 0)
    191 		return 0;
    192 	else
    193 		return 1;
    194 }
    195 
    196 /*
    197  * prefix/prefixlen permit/deny prefix/prefixlen [srcaddr]
    198  * 3ffe::/16 permit 10.0.0.0/8 10.1.1.1
    199  */
    200 static struct config *
    201 config_load1(line)
    202 	const char *line;
    203 {
    204 	struct config *conf;
    205 	char buf[BUFSIZ];
    206 	char *p;
    207 	char *token[4];
    208 	int i;
    209 
    210 	if (strlen(line) + 1 > sizeof(buf))
    211 		return NULL;
    212 	strlcpy(buf, line, sizeof(buf));
    213 
    214 	p = strchr(buf, '\n');
    215 	if (!p)
    216 		return NULL;
    217 	*p = '\0';
    218 	p = strchr(buf, '#');
    219 	if (p)
    220 		*p = '\0';
    221 	if (strlen(buf) == 0)
    222 		return NULL;
    223 
    224 	p = buf;
    225 	memset(token, 0, sizeof(token));
    226 	for (i = 0; i < sizeof(token) / sizeof(token[0]); i++) {
    227 		token[i] = strtok(p, "\t ");
    228 		p = NULL;
    229 		if (token[i] == NULL)
    230 			break;
    231 	}
    232 	/* extra tokens? */
    233 	if (strtok(p, "\t ") != NULL)
    234 		return NULL;
    235 	/* insufficient tokens */
    236 	switch (i) {
    237 	case 3:
    238 	case 4:
    239 		break;
    240 	default:
    241 		return NULL;
    242 	}
    243 
    244 	conf = (struct config *)malloc(sizeof(*conf));
    245 	if (conf == NULL)
    246 		return NULL;
    247 	memset(conf, 0, sizeof(*conf));
    248 
    249 	if (strcasecmp(token[1], "permit") == 0)
    250 		conf->permit = 1;
    251 	else if (strcasecmp(token[1], "deny") == 0)
    252 		conf->permit = 0;
    253 	else {
    254 		/* invalid keyword is considered as "deny" */
    255 		conf->permit = 0;
    256 	}
    257 
    258 	if (prefix_set(token[0], &conf->match, 1) < 0)
    259 		goto fail;
    260 	if (prefix_set(token[2], &conf->dest, 1) < 0)
    261 		goto fail;
    262 	if (token[3]) {
    263 		if (prefix_set(token[3], &conf->src, 0) < 0)
    264 			goto fail;
    265 	}
    266 
    267 	return conf;
    268 
    269 fail:
    270 	free(conf);
    271 	return NULL;
    272 }
    273 
    274 int
    275 config_load(configfile)
    276 	const char *configfile;
    277 {
    278 	FILE *fp;
    279 	char buf[BUFSIZ];
    280 	struct config *conf, *p;
    281 	struct config sentinel;
    282 
    283 	config_list = NULL;
    284 
    285 	if (!configfile)
    286 		configfile = _PATH_PREFIX_CONF;
    287 	fp = fopen(configfile, "r");
    288 	if (fp == NULL)
    289 		return -1;
    290 
    291 	p = &sentinel;
    292 	while (fgets(buf, sizeof(buf), fp) != NULL) {
    293 		conf = config_load1(buf);
    294 		if (conf) {
    295 			p->next = conf;
    296 			p = p->next;
    297 		}
    298 	}
    299 	config_list = sentinel.next;
    300 
    301 	fclose(fp);
    302 	return 0;
    303 }
    304 
    305 #if 0
    306 static void
    307 config_show1(conf)
    308 	const struct config *conf;
    309 {
    310 	const char *p;
    311 
    312 	p = prefix_string(&conf->match);
    313 	printf("%s", p ? p : "?");
    314 
    315 	if (conf->permit)
    316 		printf(" permit");
    317 	else
    318 		printf(" deny");
    319 
    320 	p = prefix_string(&conf->dest);
    321 	printf(" %s", p ? p : "?");
    322 
    323 	printf("\n");
    324 }
    325 
    326 static void
    327 config_show()
    328 {
    329 	struct config *conf;
    330 
    331 	for (conf = config_list; conf; conf = conf->next)
    332 		config_show1(conf);
    333 }
    334 #endif
    335 
    336 const struct config *
    337 config_match(sa1, sa2)
    338 	struct sockaddr *sa1, *sa2;
    339 {
    340 	static struct config conf;
    341 	const struct config *p;
    342 
    343 	if (sa1->sa_len > sizeof(conf.match.a) ||
    344 	    sa2->sa_len > sizeof(conf.dest.a))
    345 		return NULL;
    346 
    347 	memset(&conf, 0, sizeof(conf));
    348 	if (!config_list) {
    349 		conf.permit = 1;
    350 		memcpy(&conf.match.a, sa1, sa1->sa_len);
    351 		memcpy(&conf.dest.a, sa2, sa2->sa_len);
    352 		return &conf;
    353 	}
    354 
    355 	for (p = config_list; p; p = p->next)
    356 		if (prefix_match(&p->match, sa1) && prefix_match(&p->dest, sa2))
    357 			return p;
    358 
    359 	return NULL;
    360 }
    361