src/libsystemd-network/sd-dhcp-lease.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright (C) 2013 Intel Corporation. All rights reserved.
   5   Copyright (C) 2014 Tom Gundersen
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <stdlib.h>
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <stdio.h>
  25 #include <net/ethernet.h>
  26 #include <arpa/inet.h>
  27 #include <sys/param.h>
  28
  29 #include "util.h"
  30 #include "list.h"
  31 #include "mkdir.h"
  32 #include "fileio.h"
  33
  34 #include "dhcp-protocol.h"
  35 #include "dhcp-internal.h"
  36 #include "dhcp-lease-internal.h"
  37 #include "sd-dhcp-lease.h"
  38 #include "sd-dhcp-client.h"
  39 #include "network-internal.h"
  40
  41 int sd_dhcp_lease_get_address(sd_dhcp_lease *lease, struct in_addr *addr) {
  42         assert_return(lease, -EINVAL);
  43         assert_return(addr, -EINVAL);
  44
  45         addr->s_addr = lease->address;
  46
  47         return 0;
  48 }
  49
  50 int sd_dhcp_lease_get_mtu(sd_dhcp_lease *lease, uint16_t *mtu) {
  51         assert_return(lease, -EINVAL);
  52         assert_return(mtu, -EINVAL);
  53
  54         if (lease->mtu)
  55                 *mtu = lease->mtu;
  56         else
  57                 return -ENOENT;
  58
  59         return 0;
  60 }
  61
  62 int sd_dhcp_lease_get_dns(sd_dhcp_lease *lease, struct in_addr **addr, size_t *addr_size) {
  63         assert_return(lease, -EINVAL);
  64         assert_return(addr, -EINVAL);
  65         assert_return(addr_size, -EINVAL);
  66
  67         if (lease->dns_size) {
  68                 *addr_size = lease->dns_size;
  69                 *addr = lease->dns;
  70         } else
  71                 return -ENOENT;
  72
  73         return 0;
  74 }
  75
  76 int sd_dhcp_lease_get_ntp(sd_dhcp_lease *lease, struct in_addr **addr, size_t *addr_size) {
  77         assert_return(lease, -EINVAL);
  78         assert_return(addr, -EINVAL);
  79         assert_return(addr_size, -EINVAL);
  80
  81         if (lease->ntp_size) {
  82                 *addr_size = lease->ntp_size;
  83                 *addr = lease->ntp;
  84         } else
  85                 return -ENOENT;
  86
  87         return 0;
  88 }
  89
  90 int sd_dhcp_lease_get_domainname(sd_dhcp_lease *lease, const char **domainname) {
  91         assert_return(lease, -EINVAL);
  92         assert_return(domainname, -EINVAL);
  93
  94         if (lease->domainname)
  95                 *domainname = lease->domainname;
  96         else
  97                 return -ENOENT;
  98
  99         return 0;
 100 }
 101
 102 int sd_dhcp_lease_get_hostname(sd_dhcp_lease *lease, const char **hostname) {
 103         assert_return(lease, -EINVAL);
 104         assert_return(hostname, -EINVAL);
 105
 106         if (lease->hostname)
 107                 *hostname = lease->hostname;
 108         else
 109                 return -ENOENT;
 110
 111         return 0;
 112 }
 113
 114 int sd_dhcp_lease_get_root_path(sd_dhcp_lease *lease, const char **root_path) {
 115         assert_return(lease, -EINVAL);
 116         assert_return(root_path, -EINVAL);
 117
 118         if (lease->root_path)
 119                 *root_path = lease->root_path;
 120         else
 121                 return -ENOENT;
 122
 123         return 0;
 124 }
 125
 126 int sd_dhcp_lease_get_router(sd_dhcp_lease *lease, struct in_addr *addr) {
 127         assert_return(lease, -EINVAL);
 128         assert_return(addr, -EINVAL);
 129
 130         if (lease->router != INADDR_ANY)
 131                 addr->s_addr = lease->router;
 132         else
 133                 return -ENOENT;
 134
 135         return 0;
 136 }
 137
 138 int sd_dhcp_lease_get_netmask(sd_dhcp_lease *lease, struct in_addr *addr) {
 139         assert_return(lease, -EINVAL);
 140         assert_return(addr, -EINVAL);
 141
 142         addr->s_addr = lease->subnet_mask;
 143
 144         return 0;
 145 }
 146
 147 int sd_dhcp_lease_get_server_identifier(sd_dhcp_lease *lease, struct in_addr *addr) {
 148         assert_return(lease, -EINVAL);
 149         assert_return(addr, -EINVAL);
 150
 151         addr->s_addr = lease->server_address;
 152
 153         return 0;
 154 }
 155
 156 int sd_dhcp_lease_get_next_server(sd_dhcp_lease *lease, struct in_addr *addr) {
 157         assert_return(lease, -EINVAL);
 158         assert_return(addr, -EINVAL);
 159
 160         addr->s_addr = lease->next_server;
 161
 162         return 0;
 163 }
 164
 165 sd_dhcp_lease *sd_dhcp_lease_ref(sd_dhcp_lease *lease) {
 166         if (lease)
 167                 assert_se(REFCNT_INC(lease->n_ref) >= 2);
 168
 169         return lease;
 170 }
 171
 172 sd_dhcp_lease *sd_dhcp_lease_unref(sd_dhcp_lease *lease) {
 173         if (lease && REFCNT_DEC(lease->n_ref) <= 0) {
 174                 free(lease->hostname);
 175                 free(lease->domainname);
 176                 free(lease->dns);
 177                 free(lease->ntp);
 178                 free(lease);
 179         }
 180
 181         return NULL;
 182 }
 183
 184 static void lease_parse_u32(const uint8_t *option, size_t len, uint32_t *ret, uint32_t min) {
 185         be32_t val;
 186
 187         assert(option);
 188         assert(ret);
 189
 190         if (len == 4) {
 191                 memcpy(&val, option, 4);
 192                 *ret = be32toh(val);
 193
 194                 if (*ret < min)
 195                         *ret = min;
 196         }
 197 }
 198
 199 static void lease_parse_u16(const uint8_t *option, size_t len, uint16_t *ret, uint16_t min) {
 200         be16_t val;
 201
 202         assert(option);
 203         assert(ret);
 204
 205         if (len == 2) {
 206                 memcpy(&val, option, 2);
 207                 *ret = be16toh(val);
 208
 209                 if (*ret < min)
 210                         *ret = min;
 211         }
 212 }
 213
 214 static void lease_parse_be32(const uint8_t *option, size_t len, be32_t *ret) {
 215         assert(option);
 216         assert(ret);
 217
 218         if (len == 4)
 219                 memcpy(ret, option, 4);
 220 }
 221
 222 static int lease_parse_string(const uint8_t *option, size_t len, char **ret) {
 223         assert(option);
 224         assert(ret);
 225
 226         if (len >= 1) {
 227                 char *string;
 228
 229                 string = strndup((const char *)option, len);
 230                 if (!string)
 231                         return -errno;
 232
 233                 free(*ret);
 234                 *ret = string;
 235         }
 236
 237         return 0;
 238 }
 239
 240 static int lease_parse_in_addrs(const uint8_t *option, size_t len, struct in_addr **ret, size_t *ret_size) {
 241         assert(option);
 242         assert(ret);
 243         assert(ret_size);
 244
 245         if (len && !(len % 4)) {
 246                 size_t size;
 247                 struct in_addr *addresses;
 248
 249                 size = len / 4;
 250
 251                 addresses = newdup(struct in_addr, option, size);
 252                 if (!addresses)
 253                         return -ENOMEM;
 254
 255                 free(*ret);
 256                 *ret = addresses;
 257                 *ret_size = size;
 258         }
 259
 260         return 0;
 261 }
 262
 263 int dhcp_lease_parse_options(uint8_t code, uint8_t len, const uint8_t *option,
 264                               void *user_data) {
 265         sd_dhcp_lease *lease = user_data;
 266         int r;
 267
 268         assert(lease);
 269
 270         switch(code) {
 271
 272         case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
 273                 lease_parse_u32(option, len, &lease->lifetime, 1);
 274
 275                 break;
 276
 277         case DHCP_OPTION_SERVER_IDENTIFIER:
 278                 lease_parse_be32(option, len, &lease->server_address);
 279
 280                 break;
 281
 282         case DHCP_OPTION_SUBNET_MASK:
 283                 lease_parse_be32(option, len, &lease->subnet_mask);
 284
 285                 break;
 286
 287         case DHCP_OPTION_ROUTER:
 288                 lease_parse_be32(option, len, &lease->router);
 289
 290                 break;
 291
 292         case DHCP_OPTION_DOMAIN_NAME_SERVER:
 293                 r = lease_parse_in_addrs(option, len, &lease->dns, &lease->dns_size);
 294                 if (r < 0)
 295                         return r;
 296
 297                 break;
 298
 299         case DHCP_OPTION_NTP_SERVER:
 300                 r = lease_parse_in_addrs(option, len, &lease->ntp, &lease->ntp_size);
 301                 if (r < 0)
 302                         return r;
 303
 304                 break;
 305
 306         case DHCP_OPTION_INTERFACE_MTU:
 307                 lease_parse_u16(option, len, &lease->mtu, 68);
 308
 309                 break;
 310
 311         case DHCP_OPTION_DOMAIN_NAME:
 312                 r = lease_parse_string(option, len, &lease->domainname);
 313                 if (r < 0)
 314                         return r;
 315
 316                 break;
 317
 318         case DHCP_OPTION_HOST_NAME:
 319                 r = lease_parse_string(option, len, &lease->hostname);
 320                 if (r < 0)
 321                         return r;
 322
 323                 break;
 324
 325         case DHCP_OPTION_ROOT_PATH:
 326                 r = lease_parse_string(option, len, &lease->root_path);
 327                 if (r < 0)
 328                         return r;
 329
 330                 break;
 331
 332         case DHCP_OPTION_RENEWAL_T1_TIME:
 333                 lease_parse_u32(option, len, &lease->t1, 1);
 334
 335                 break;
 336
 337         case DHCP_OPTION_REBINDING_T2_TIME:
 338                 lease_parse_u32(option, len, &lease->t2, 1);
 339
 340                 break;
 341         }
 342
 343         return 0;
 344 }
 345
 346 int dhcp_lease_new(sd_dhcp_lease **ret) {
 347         sd_dhcp_lease *lease;
 348
 349         lease = new0(sd_dhcp_lease, 1);
 350         if (!lease)
 351                 return -ENOMEM;
 352
 353         lease->router = INADDR_ANY;
 354         lease->n_ref = REFCNT_INIT;
 355
 356         *ret = lease;
 357         return 0;
 358 }
 359
 360 int dhcp_lease_save(sd_dhcp_lease *lease, const char *lease_file) {
 361         _cleanup_free_ char *temp_path = NULL;
 362         _cleanup_fclose_ FILE *f = NULL;
 363         struct in_addr address;
 364         struct in_addr *addresses;
 365         size_t addresses_size;
 366         const char *string;
 367         uint16_t mtu;
 368         int r;
 369
 370         assert(lease);
 371         assert(lease_file);
 372
 373         r = fopen_temporary(lease_file, &f, &temp_path);
 374         if (r < 0)
 375                 goto finish;
 376
 377         fchmod(fileno(f), 0644);
 378
 379         r = sd_dhcp_lease_get_address(lease, &address);
 380         if (r < 0)
 381                 goto finish;
 382
 383         fprintf(f,
 384                 "# This is private data. Do not parse.\n"
 385                 "ADDRESS=%s\n", inet_ntoa(address));
 386
 387         r = sd_dhcp_lease_get_netmask(lease, &address);
 388         if (r < 0)
 389                 goto finish;
 390
 391         fprintf(f, "NETMASK=%s\n", inet_ntoa(address));
 392
 393         r = sd_dhcp_lease_get_router(lease, &address);
 394         if (r >= 0)
 395                 fprintf(f, "ROUTER=%s\n", inet_ntoa(address));
 396
 397         r = sd_dhcp_lease_get_server_identifier(lease, &address);
 398         if (r >= 0)
 399                 fprintf(f, "SERVER_ADDRESS=%s\n",
 400                         inet_ntoa(address));
 401
 402         r = sd_dhcp_lease_get_next_server(lease, &address);
 403         if (r >= 0)
 404                 fprintf(f, "NEXT_SERVER=%s\n", inet_ntoa(address));
 405
 406         r = sd_dhcp_lease_get_mtu(lease, &mtu);
 407         if (r >= 0)
 408                 fprintf(f, "MTU=%" PRIu16 "\n", mtu);
 409
 410         r = sd_dhcp_lease_get_dns(lease, &addresses, &addresses_size);
 411         if (r >= 0)
 412                 serialize_in_addrs(f, "DNS", addresses, addresses_size);
 413
 414         r = sd_dhcp_lease_get_ntp(lease, &addresses, &addresses_size);
 415         if (r >= 0)
 416                 serialize_in_addrs(f, "NTP", addresses, addresses_size);
 417
 418         r = sd_dhcp_lease_get_domainname(lease, &string);
 419         if (r >= 0)
 420                 fprintf(f, "DOMAINNAME=%s\n", string);
 421
 422         r = sd_dhcp_lease_get_hostname(lease, &string);
 423         if (r >= 0)
 424                 fprintf(f, "HOSTNAME=%s\n", string);
 425
 426         r = sd_dhcp_lease_get_root_path(lease, &string);
 427         if (r >= 0)
 428                 fprintf(f, "ROOT_PATH=%s\n", string);
 429
 430         r = 0;
 431
 432         fflush(f);
 433
 434         if (ferror(f) || rename(temp_path, lease_file) < 0) {
 435                 r = -errno;
 436                 unlink(lease_file);
 437                 unlink(temp_path);
 438         }
 439
 440 finish:
 441         if (r < 0)
 442                 log_error("Failed to save lease data %s: %s", lease_file, strerror(-r));
 443
 444         return r;
 445 }
 446
 447 int dhcp_lease_load(const char *lease_file, sd_dhcp_lease **ret) {
 448         _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
 449         _cleanup_free_ char *address = NULL, *router = NULL, *netmask = NULL,
 450                             *server_address = NULL, *next_server = NULL,
 451                             *dns = NULL, *ntp = NULL, *mtu = NULL;
 452         struct in_addr addr;
 453         int r;
 454
 455         assert(lease_file);
 456         assert(ret);
 457
 458         r = dhcp_lease_new(&lease);
 459         if (r < 0)
 460                 return r;
 461
 462         r = parse_env_file(lease_file, NEWLINE,
 463                            "ADDRESS", &address,
 464                            "ROUTER", &router,
 465                            "NETMASK", &netmask,
 466                            "SERVER_IDENTIFIER", &server_address,
 467                            "NEXT_SERVER", &next_server,
 468                            "DNS", &dns,
 469                            "NTP", &ntp,
 470                            "MTU", &mtu,
 471                            "DOMAINNAME", &lease->domainname,
 472                            "HOSTNAME", &lease->hostname,
 473                            "ROOT_PATH", &lease->root_path,
 474                            NULL);
 475         if (r < 0) {
 476                 if (r == -ENOENT)
 477                         return 0;
 478
 479                 log_error("Failed to read %s: %s", lease_file, strerror(-r));
 480                 return r;
 481         }
 482
 483         r = inet_pton(AF_INET, address, &addr);
 484         if (r < 0)
 485                 return r;
 486
 487         lease->address = addr.s_addr;
 488
 489         if (router) {
 490                 r = inet_pton(AF_INET, router, &addr);
 491                 if (r < 0)
 492                         return r;
 493
 494                 lease->router = addr.s_addr;
 495         }
 496
 497         r = inet_pton(AF_INET, netmask, &addr);
 498         if (r < 0)
 499                 return r;
 500
 501         lease->subnet_mask = addr.s_addr;
 502
 503         if (server_address) {
 504                 r = inet_pton(AF_INET, server_address, &addr);
 505                 if (r < 0)
 506                         return r;
 507
 508                 lease->server_address = addr.s_addr;
 509         }
 510
 511         if (next_server) {
 512                 r = inet_pton(AF_INET, next_server, &addr);
 513                 if (r < 0)
 514                         return r;
 515
 516                 lease->next_server = addr.s_addr;
 517         }
 518
 519         if (dns) {
 520                 r = deserialize_in_addrs(&lease->dns, &lease->dns_size, dns);
 521                 if (r < 0)
 522                         return r;
 523         }
 524
 525         if (ntp) {
 526                 r = deserialize_in_addrs(&lease->ntp, &lease->ntp_size, dns);
 527                 if (r < 0)
 528                         return r;
 529         }
 530
 531         if (mtu) {
 532                 uint16_t u;
 533                 if (sscanf(mtu, "%" SCNu16, &u) > 0)
 534                         lease->mtu = u;
 535         }
 536
 537         *ret = lease;
 538         lease = NULL;
 539
 540         return 0;
 541 }
 542
 543 int dhcp_lease_set_default_subnet_mask(sd_dhcp_lease *lease) {
 544         uint32_t address;
 545
 546         assert(lease);
 547         assert(lease->address != INADDR_ANY);
 548
 549         address = be32toh(lease->address);
 550
 551         /* fall back to the default subnet masks based on address class */
 552
 553         if ((address >> 31) == 0x0)
 554                 /* class A, leading bits: 0 */
 555                 lease->subnet_mask = htobe32(0xff000000);
 556         else if ((address >> 30) == 0x2)
 557                 /* class B, leading bits 10 */
 558                 lease->subnet_mask = htobe32(0xffff0000);
 559         else if ((address >> 29) == 0x6)
 560                 /* class C, leading bits 110 */
 561                 lease->subnet_mask = htobe32(0xffffff00);
 562         else
 563                 /* class D or E, no default mask. give up */
 564                 return -ERANGE;
 565
 566         return 0;
 567 }