tinc-vpn.org Git - tinc/blob - src/subnet_parse.c

   1 /*
   2     subnet_parse.c -- handle subnet parsing
   3     Copyright (C) 2000-2012 Guus Sliepen <guus@tinc-vpn.org>,
   4                   2000-2005 Ivo Timmermans
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License along
  17     with this program; if not, write to the Free Software Foundation, Inc.,
  18     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19 */
  20
  21 #include "system.h"
  22
  23 #include "logger.h"
  24 #include "net.h"
  25 #include "netutl.h"
  26 #include "subnet.h"
  27 #include "utils.h"
  28 #include "xalloc.h"
  29
  30 /* Subnet mask handling */
  31
  32 int maskcmp(const void *va, const void *vb, int masklen) {
  33         int i, m, result;
  34         const char *a = va;
  35         const char *b = vb;
  36
  37         for(m = masklen, i = 0; m >= 8; m -= 8, i++) {
  38                 result = a[i] - b[i];
  39                 if(result)
  40                         return result;
  41         }
  42
  43         if(m)
  44                 return (a[i] & (0x100 - (1 << (8 - m)))) -
  45                         (b[i] & (0x100 - (1 << (8 - m))));
  46
  47         return 0;
  48 }
  49
  50 void mask(void *va, int masklen, int len) {
  51         int i;
  52         char *a = va;
  53
  54         i = masklen / 8;
  55         masklen %= 8;
  56
  57         if(masklen)
  58                 a[i++] &= (0x100 - (1 << (8 - masklen)));
  59
  60         for(; i < len; i++)
  61                 a[i] = 0;
  62 }
  63
  64 void maskcpy(void *va, const void *vb, int masklen, int len) {
  65         int i, m;
  66         char *a = va;
  67         const char *b = vb;
  68
  69         for(m = masklen, i = 0; m >= 8; m -= 8, i++)
  70                 a[i] = b[i];
  71
  72         if(m) {
  73                 a[i] = b[i] & (0x100 - (1 << (8 - m)));
  74                 i++;
  75         }
  76
  77         for(; i < len; i++)
  78                 a[i] = 0;
  79 }
  80
  81 bool maskcheck(const void *va, int masklen, int len) {
  82         int i;
  83         const char *a = va;
  84
  85         i = masklen / 8;
  86         masklen %= 8;
  87
  88         if(masklen && a[i++] & (0xff >> masklen))
  89                 return false;
  90
  91         for(; i < len; i++)
  92                 if(a[i] != 0)
  93                         return false;
  94
  95         return true;
  96 }
  97
  98 /* Subnet comparison */
  99
 100 static int subnet_compare_mac(const subnet_t *a, const subnet_t *b) {
 101         int result;
 102
 103         result = memcmp(&a->net.mac.address, &b->net.mac.address, sizeof a->net.mac.address);
 104
 105         if(result)
 106                 return result;
 107
 108         result = a->weight - b->weight;
 109
 110         if(result || !a->owner || !b->owner)
 111                 return result;
 112
 113         return strcmp(a->owner->name, b->owner->name);
 114 }
 115
 116 static int subnet_compare_ipv4(const subnet_t *a, const subnet_t *b) {
 117         int result;
 118
 119         result = b->net.ipv4.prefixlength - a->net.ipv4.prefixlength;
 120
 121         if(result)
 122                 return result;
 123
 124         result = memcmp(&a->net.ipv4.address, &b->net.ipv4.address, sizeof(ipv4_t));
 125
 126         if(result)
 127                 return result;
 128
 129         result = a->weight - b->weight;
 130
 131         if(result || !a->owner || !b->owner)
 132                 return result;
 133
 134         return strcmp(a->owner->name, b->owner->name);
 135 }
 136
 137 static int subnet_compare_ipv6(const subnet_t *a, const subnet_t *b) {
 138         int result;
 139
 140         result = b->net.ipv6.prefixlength - a->net.ipv6.prefixlength;
 141
 142         if(result)
 143                 return result;
 144
 145         result = memcmp(&a->net.ipv6.address, &b->net.ipv6.address, sizeof(ipv6_t));
 146
 147         if(result)
 148                 return result;
 149
 150         result = a->weight - b->weight;
 151
 152         if(result || !a->owner || !b->owner)
 153                 return result;
 154
 155         return strcmp(a->owner->name, b->owner->name);
 156 }
 157
 158 int subnet_compare(const subnet_t *a, const subnet_t *b) {
 159         int result;
 160
 161         result = a->type - b->type;
 162
 163         if(result)
 164                 return result;
 165
 166         switch (a->type) {
 167         case SUBNET_MAC:
 168                 return subnet_compare_mac(a, b);
 169         case SUBNET_IPV4:
 170                 return subnet_compare_ipv4(a, b);
 171         case SUBNET_IPV6:
 172                 return subnet_compare_ipv6(a, b);
 173         default:
 174                 logger(DEBUG_ALWAYS, LOG_ERR, "subnet_compare() was called with unknown subnet type %d, exitting!", a->type);
 175                 exit(1);
 176         }
 177
 178         return 0;
 179 }
 180
 181 /* Ascii representation of subnets */
 182
 183 bool str2net(subnet_t *subnet, const char *subnetstr) {
 184         char str[1024];
 185         strncpy(str, subnetstr, sizeof(str));
 186         int consumed;
 187
 188         int weight = 10;
 189         char *weight_separator = strchr(str, '#');
 190         if (weight_separator) {
 191                 char *weight_str = weight_separator + 1;
 192                 if (sscanf(weight_str, "%d%n", &weight, &consumed) < 1)
 193                         return false;
 194                 if (weight_str[consumed])
 195                         return false;
 196                 *weight_separator = 0;
 197         }
 198
 199         int prefixlength = -1;
 200         char *prefixlength_separator = strchr(str, '/');
 201         if (prefixlength_separator) {
 202                 char* prefixlength_str = prefixlength_separator + 1;
 203                 if (sscanf(prefixlength_str, "%d%n", &prefixlength, &consumed) < 1)
 204                         return false;
 205                 if (prefixlength_str[consumed])
 206                         return false;
 207                 *prefixlength_separator = 0;
 208
 209                 if (prefixlength < 0)
 210                         return false;
 211         }
 212
 213         uint16_t x[8];
 214         if (sscanf(str, "%hx:%hx:%hx:%hx:%hx:%hx%n", &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &consumed) >= 6 && !str[consumed]) {
 215                 /*
 216                    Normally we should check that each part has two digits to prevent ambiguities.
 217                    However, in old tinc versions net2str() will agressively return MAC addresses with one-digit parts,
 218                    so we have to accept them otherwise we would be unable to parse ADD_SUBNET messages.
 219                 */
 220                 if (prefixlength >= 0)
 221                         return false;
 222
 223                 subnet->type = SUBNET_MAC;
 224                 subnet->weight = weight;
 225                 for(int i = 0; i < 6; i++)
 226                         subnet->net.mac.address.x[i] = x[i];
 227                 return true;
 228         }
 229
 230         if (sscanf(str, "%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !str[consumed]) {
 231                 if (prefixlength == -1)
 232                         prefixlength = 32;
 233                 if (prefixlength > 32)
 234                         return false;
 235
 236                 subnet->type = SUBNET_IPV4;
 237                 subnet->net.ipv4.prefixlength = prefixlength;
 238                 subnet->weight = weight;
 239                 for(int i = 0; i < 4; i++) {
 240                         if (x[i] > 255)
 241                                 return false;
 242                         subnet->net.ipv4.address.x[i] = x[i];
 243                 }
 244                 return true;
 245         }
 246
 247         /* IPv6 */
 248
 249         char* last_colon = strrchr(str, ':');
 250         if (last_colon && sscanf(last_colon, ":%hu.%hu.%hu.%hu%n", &x[0], &x[1], &x[2], &x[3], &consumed) >= 4 && !last_colon[consumed]) {
 251                 /* Dotted quad suffix notation, convert to standard IPv6 notation */
 252                 for (int i = 0; i < 4; i++)
 253                         if (x[i] > 255)
 254                                 return false;
 255                 sprintf(last_colon, ":%02hx%02hx:%02hx%02hx", x[0], x[1], x[2], x[3]);
 256         }
 257
 258         char* double_colon = strstr(str, "::");
 259         if (double_colon) {
 260                 /* Figure out how many zero groups we need to expand */
 261                 int zero_group_count = 8;
 262                 for (const char* cur = str; *cur; *cur && cur++)
 263                         if (*cur != ':') {
 264                                 zero_group_count--;
 265                                 for (; *cur && *cur != ':'; cur++);
 266                         }
 267                 if (zero_group_count < 1)
 268                         return false;
 269
 270                 /* Split the double colon in the middle to make room for zero groups */
 271                 double_colon++;
 272                 memmove(double_colon + (zero_group_count * 2 - 1), double_colon, strlen(double_colon) + 1);
 273
 274                 /* Write zero groups in the resulting gap, overwriting the second colon */
 275                 for (int i = 0; i < zero_group_count; i++)
 276                         memcpy(&double_colon[i * 2], "0:", 2);
 277
 278                 /* Remove any leading or trailing colons */
 279                 if (str[0] == ':')
 280                         memmove(&str[0], &str[1], strlen(&str[1]) + 1);
 281                 if (str[strlen(str) - 1] == ':')
 282                         str[strlen(str) - 1] = 0;
 283         }
 284
 285         if (sscanf(str, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx%n",
 286                 &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &x[6], &x[7], &consumed) >= 8 && !str[consumed]) {
 287                 if (prefixlength == -1)
 288                         prefixlength = 128;
 289                 if (prefixlength > 128)
 290                         return false;
 291
 292                 subnet->type = SUBNET_IPV6;
 293                 subnet->net.ipv6.prefixlength = prefixlength;
 294                 subnet->weight = weight;
 295                 for(int i = 0; i < 8; i++)
 296                         subnet->net.ipv6.address.x[i] = htons(x[i]);
 297                 return true;
 298         }
 299
 300         return false;
 301 }
 302
 303 bool net2str(char *netstr, int len, const subnet_t *subnet) {
 304         if(!netstr || !subnet) {
 305                 logger(DEBUG_ALWAYS, LOG_ERR, "net2str() was called with netstr=%p, subnet=%p!", netstr, subnet);
 306                 return false;
 307         }
 308
 309         switch (subnet->type) {
 310                 case SUBNET_MAC:
 311                         snprintf(netstr, len, "%hx:%hx:%hx:%hx:%hx:%hx#%d",
 312                                          subnet->net.mac.address.x[0],
 313                                          subnet->net.mac.address.x[1],
 314                                          subnet->net.mac.address.x[2],
 315                                          subnet->net.mac.address.x[3],
 316                                          subnet->net.mac.address.x[4],
 317                                          subnet->net.mac.address.x[5],
 318                                          subnet->weight);
 319                         break;
 320
 321                 case SUBNET_IPV4:
 322                         snprintf(netstr, len, "%hu.%hu.%hu.%hu/%d#%d",
 323                                          subnet->net.ipv4.address.x[0],
 324                                          subnet->net.ipv4.address.x[1],
 325                                          subnet->net.ipv4.address.x[2],
 326                                          subnet->net.ipv4.address.x[3],
 327                                          subnet->net.ipv4.prefixlength,
 328                                          subnet->weight);
 329                         break;
 330
 331                 case SUBNET_IPV6:
 332                         snprintf(netstr, len, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx/%d#%d",
 333                                          ntohs(subnet->net.ipv6.address.x[0]),
 334                                          ntohs(subnet->net.ipv6.address.x[1]),
 335                                          ntohs(subnet->net.ipv6.address.x[2]),
 336                                          ntohs(subnet->net.ipv6.address.x[3]),
 337                                          ntohs(subnet->net.ipv6.address.x[4]),
 338                                          ntohs(subnet->net.ipv6.address.x[5]),
 339                                          ntohs(subnet->net.ipv6.address.x[6]),
 340                                          ntohs(subnet->net.ipv6.address.x[7]),
 341                                          subnet->net.ipv6.prefixlength,
 342                                          subnet->weight);
 343                         break;
 344
 345                 default:
 346                         logger(DEBUG_ALWAYS, LOG_ERR, "net2str() was called with unknown subnet type %d, exiting!", subnet->type);
 347                         exit(1);
 348         }
 349
 350         return true;
 351 }