usr.sbin/faithd/prefix.c

   1 /*      $KAME: prefix.c,v 1.9 2001/07/02 14:36:49 itojun Exp $  */
   2 /*      $FreeBSD: src/usr.sbin/faithd/prefix.c,v 1.1.2.2 2002/04/28 05:40:29 suz 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(const char *, struct prefix *, int);
  51 static struct config *config_load1(const char *);
  52 #if 0
  53 static void config_show1(const struct config *);
  54 static void config_show(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(const char *s, struct prefix *prefix, int slash)
  66 {
  67         char *p, *q, *r;
  68         struct addrinfo hints, *res = NULL;
  69         int max;
  70
  71         p = strdup(s);
  72         q = strchr(p, '/');
  73         if (q) {
  74                 if (!slash)
  75                         goto fail;
  76                 *q++ = '\0';
  77         }
  78
  79         memset(&hints, 0, sizeof(hints));
  80         hints.ai_family = PF_UNSPEC;
  81         hints.ai_socktype = SOCK_DGRAM; /*dummy*/
  82         hints.ai_flags = AI_NUMERICHOST;
  83         if (getaddrinfo(p, "0", &hints, &res))
  84                 goto fail;
  85         if (res->ai_next || res->ai_addrlen > sizeof(prefix->a))
  86                 goto fail;
  87         memcpy(&prefix->a, res->ai_addr, res->ai_addrlen);
  88
  89         switch (prefix->a.ss_family) {
  90         case AF_INET:
  91                 max = 32;
  92                 break;
  93         case AF_INET6:
  94                 max = 128;
  95                 break;
  96         default:
  97                 max = -1;
  98                 break;
  99         }
 100
 101         if (q) {
 102                 r = NULL;
 103                 prefix->l = (int)strtoul(q, &r, 10);
 104                 if (!*q || *r)
 105                         goto fail;
 106                 if (prefix->l < 0 || prefix->l > max)
 107                         goto fail;
 108         } else
 109                 prefix->l = max;
 110
 111         if (p)
 112                 free(p);
 113         if (res)
 114                 freeaddrinfo(res);
 115         return 0;
 116
 117 fail:
 118         if (p)
 119                 free(p);
 120         if (res)
 121                 freeaddrinfo(res);
 122         return -1;
 123 }
 124
 125 const char *
 126 prefix_string(const struct prefix *prefix)
 127 {
 128         static char buf[NI_MAXHOST + 20];
 129         char hbuf[NI_MAXHOST];
 130
 131         if (getnameinfo((const struct sockaddr *)&prefix->a, prefix->a.ss_len,
 132             hbuf, sizeof(hbuf), NULL, 0, niflags))
 133                 return NULL;
 134         snprintf(buf, sizeof(buf), "%s/%d", hbuf, prefix->l);
 135         return buf;
 136 }
 137
 138 int
 139 prefix_match(const struct prefix *prefix, const struct sockaddr *sa)
 140 {
 141         struct sockaddr_storage a, b;
 142         char *pa, *pb;
 143         int off, l;
 144
 145         if (prefix->a.ss_family != sa->sa_family ||
 146             prefix->a.ss_len != sa->sa_len)
 147                 return 0;
 148
 149         if (prefix->a.ss_len > sizeof(a) || sa->sa_len > sizeof(b))
 150                 return 0;
 151
 152         switch (prefix->a.ss_family) {
 153         case AF_INET:
 154                 off = offsetof(struct sockaddr_in, sin_addr);
 155                 break;
 156         case AF_INET6:
 157                 off = offsetof(struct sockaddr_in6, sin6_addr);
 158                 break;
 159         default:
 160                 if (memcmp(&prefix->a, sa, prefix->a.ss_len) != 0)
 161                         return 0;
 162                 else
 163                         return 1;
 164         }
 165
 166         memcpy(&a, &prefix->a, prefix->a.ss_len);
 167         memcpy(&b, sa, sa->sa_len);
 168         l = prefix->l / 8 + (prefix->l % 8 ? 1 : 0);
 169
 170         /* overrun check */
 171         if (off + l > a.ss_len)
 172                 return 0;
 173
 174         pa = ((char *)&a) + off;
 175         pb = ((char *)&b) + off;
 176         if (prefix->l % 8) {
 177                 pa[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
 178                 pb[prefix->l / 8] &= 0xff00 >> (prefix->l % 8);
 179         }
 180         if (memcmp(pa, pb, l) != 0)
 181                 return 0;
 182         else
 183                 return 1;
 184 }
 185
 186 /*
 187  * prefix/prefixlen permit/deny prefix/prefixlen [srcaddr]
 188  * 3ffe::/16 permit 10.0.0.0/8 10.1.1.1
 189  */
 190 static struct config *
 191 config_load1(const char *line)
 192 {
 193         struct config *conf;
 194         char buf[BUFSIZ];
 195         char *p;
 196         char *token[4];
 197         int i;
 198
 199         if (strlen(line) + 1 > sizeof(buf))
 200                 return NULL;
 201         strlcpy(buf, line, sizeof(buf));
 202
 203         p = strchr(buf, '\n');
 204         if (!p)
 205                 return NULL;
 206         *p = '\0';
 207         p = strchr(buf, '#');
 208         if (p)
 209                 *p = '\0';
 210         if (strlen(buf) == 0)
 211                 return NULL;
 212
 213         p = buf;
 214         memset(token, 0, sizeof(token));
 215         for (i = 0; i < sizeof(token) / sizeof(token[0]); i++) {
 216                 token[i] = strtok(p, "\t ");
 217                 p = NULL;
 218                 if (token[i] == NULL)
 219                         break;
 220         }
 221         /* extra tokens? */
 222         if (strtok(p, "\t ") != NULL)
 223                 return NULL;
 224         /* insufficient tokens */
 225         switch (i) {
 226         case 3:
 227         case 4:
 228                 break;
 229         default:
 230                 return NULL;
 231         }
 232
 233         conf = (struct config *)malloc(sizeof(*conf));
 234         if (conf == NULL)
 235                 return NULL;
 236         memset(conf, 0, sizeof(*conf));
 237
 238         if (strcasecmp(token[1], "permit") == 0)
 239                 conf->permit = 1;
 240         else if (strcasecmp(token[1], "deny") == 0)
 241                 conf->permit = 0;
 242         else {
 243                 /* invalid keyword is considered as "deny" */
 244                 conf->permit = 0;
 245         }
 246
 247         if (prefix_set(token[0], &conf->match, 1) < 0)
 248                 goto fail;
 249         if (prefix_set(token[2], &conf->dest, 1) < 0)
 250                 goto fail;
 251         if (token[3]) {
 252                 if (prefix_set(token[3], &conf->src, 0) < 0)
 253                         goto fail;
 254         }
 255
 256         return conf;
 257
 258 fail:
 259         free(conf);
 260         return NULL;
 261 }
 262
 263 int
 264 config_load(const char *configfile)
 265 {
 266         FILE *fp;
 267         char buf[BUFSIZ];
 268         struct config *conf, *p;
 269         struct config sentinel;
 270
 271         config_list = NULL;
 272
 273         if (!configfile)
 274                 configfile = _PATH_PREFIX_CONF;
 275         fp = fopen(configfile, "r");
 276         if (fp == NULL)
 277                 return -1;
 278
 279         p = &sentinel;
 280         while (fgets(buf, sizeof(buf), fp) != NULL) {
 281                 conf = config_load1(buf);
 282                 if (conf) {
 283                         p->next = conf;
 284                         p = p->next;
 285                 }
 286         }
 287         config_list = sentinel.next;
 288
 289         fclose(fp);
 290         return 0;
 291 }
 292
 293 #if 0
 294 static void
 295 config_show1(const struct config *conf)
 296 {
 297         const char *p;
 298
 299         p = prefix_string(&conf->match);
 300         printf("%s", p ? p : "?");
 301
 302         if (conf->permit)
 303                 printf(" permit");
 304         else
 305                 printf(" deny");
 306
 307         p = prefix_string(&conf->dest);
 308         printf(" %s", p ? p : "?");
 309
 310         printf("\n");
 311 }
 312
 313 static void
 314 config_show(void)
 315 {
 316         struct config *conf;
 317
 318         for (conf = config_list; conf; conf = conf->next)
 319                 config_show1(conf);
 320 }
 321 #endif
 322
 323 const struct config *
 324 config_match(struct sockaddr *sa1, struct sockaddr *sa2)
 325 {
 326         static struct config conf;
 327         const struct config *p;
 328
 329         if (sa1->sa_len > sizeof(conf.match.a) ||
 330             sa2->sa_len > sizeof(conf.dest.a))
 331                 return NULL;
 332
 333         memset(&conf, 0, sizeof(conf));
 334         if (!config_list) {
 335                 conf.permit = 1;
 336                 memcpy(&conf.match.a, sa1, sa1->sa_len);
 337                 memcpy(&conf.dest.a, sa2, sa2->sa_len);
 338                 return &conf;
 339         }
 340
 341         for (p = config_list; p; p = p->next)
 342                 if (prefix_match(&p->match, sa1) && prefix_match(&p->dest, sa2))
 343                         return p;
 344
 345         return NULL;
 346 }