src/libsystemd/sd-netlink/netlink-message.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2013 Tom Gundersen <teg@jklm.no>
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <netinet/in.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23
  24 #include "sd-netlink.h"
  25
  26 #include "alloc-util.h"
  27 #include "format-util.h"
  28 #include "missing.h"
  29 #include "netlink-internal.h"
  30 #include "netlink-types.h"
  31 #include "netlink-util.h"
  32 #include "refcnt.h"
  33 #include "socket-util.h"
  34 #include "util.h"
  35
  36 #define GET_CONTAINER(m, i) ((i) < (m)->n_containers ? (struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset) : NULL)
  37 #define PUSH_CONTAINER(m, new) (m)->container_offsets[(m)->n_containers++] = (uint8_t*)(new) - (uint8_t*)(m)->hdr;
  38
  39 #define RTA_TYPE(rta) ((rta)->rta_type & NLA_TYPE_MASK)
  40 #define RTA_FLAGS(rta) ((rta)->rta_type & ~NLA_TYPE_MASK)
  41
  42 int message_new_empty(sd_netlink *rtnl, sd_netlink_message **ret) {
  43         sd_netlink_message *m;
  44
  45         assert_return(ret, -EINVAL);
  46
  47         /* Note that 'rtnl' is currently unused, if we start using it internally
  48            we must take care to avoid problems due to mutual references between
  49            buses and their queued messages. See sd-bus.
  50          */
  51
  52         m = new0(sd_netlink_message, 1);
  53         if (!m)
  54                 return -ENOMEM;
  55
  56         m->n_ref = REFCNT_INIT;
  57
  58         m->sealed = false;
  59
  60         *ret = m;
  61
  62         return 0;
  63 }
  64
  65 int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type) {
  66         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
  67         const NLType *nl_type;
  68         size_t size;
  69         int r;
  70
  71         r = type_system_get_type(&type_system_root, &nl_type, type);
  72         if (r < 0)
  73                 return r;
  74
  75         if (type_get_type(nl_type) != NETLINK_TYPE_NESTED)
  76                 return -EINVAL;
  77
  78         r = message_new_empty(rtnl, &m);
  79         if (r < 0)
  80                 return r;
  81
  82         size = NLMSG_SPACE(type_get_size(nl_type));
  83
  84         assert(size >= sizeof(struct nlmsghdr));
  85         m->hdr = malloc0(size);
  86         if (!m->hdr)
  87                 return -ENOMEM;
  88
  89         m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
  90
  91         type_get_type_system(nl_type, &m->containers[0].type_system);
  92         m->hdr->nlmsg_len = size;
  93         m->hdr->nlmsg_type = type;
  94
  95         *ret = m;
  96         m = NULL;
  97
  98         return 0;
  99 }
 100
 101 int sd_netlink_message_request_dump(sd_netlink_message *m, int dump) {
 102         assert_return(m, -EINVAL);
 103         assert_return(m->hdr, -EINVAL);
 104         assert_return(m->hdr->nlmsg_type == RTM_GETLINK  ||
 105                       m->hdr->nlmsg_type == RTM_GETADDR  ||
 106                       m->hdr->nlmsg_type == RTM_GETROUTE ||
 107                       m->hdr->nlmsg_type == RTM_GETNEIGH ||
 108                       m->hdr->nlmsg_type == RTM_GETADDRLABEL ,
 109                       -EINVAL);
 110
 111         SET_FLAG(m->hdr->nlmsg_flags, NLM_F_DUMP, dump);
 112
 113         return 0;
 114 }
 115
 116 sd_netlink_message *sd_netlink_message_ref(sd_netlink_message *m) {
 117         if (m)
 118                 assert_se(REFCNT_INC(m->n_ref) >= 2);
 119
 120         return m;
 121 }
 122
 123 sd_netlink_message *sd_netlink_message_unref(sd_netlink_message *m) {
 124         sd_netlink_message *t;
 125
 126         while (m && REFCNT_DEC(m->n_ref) == 0) {
 127                 unsigned i;
 128
 129                 free(m->hdr);
 130
 131                 for (i = 0; i <= m->n_containers; i++)
 132                         free(m->containers[i].attributes);
 133
 134                 t = m;
 135                 m = m->next;
 136                 free(t);
 137         }
 138
 139         return NULL;
 140 }
 141
 142 int sd_netlink_message_get_type(sd_netlink_message *m, uint16_t *type) {
 143         assert_return(m, -EINVAL);
 144         assert_return(type, -EINVAL);
 145
 146         *type = m->hdr->nlmsg_type;
 147
 148         return 0;
 149 }
 150
 151 int sd_netlink_message_set_flags(sd_netlink_message *m, uint16_t flags) {
 152         assert_return(m, -EINVAL);
 153         assert_return(flags, -EINVAL);
 154
 155         m->hdr->nlmsg_flags = flags;
 156
 157         return 0;
 158 }
 159
 160 int sd_netlink_message_is_broadcast(sd_netlink_message *m) {
 161         assert_return(m, -EINVAL);
 162
 163         return m->broadcast;
 164 }
 165
 166 /* If successful the updated message will be correctly aligned, if
 167    unsuccessful the old message is untouched. */
 168 static int add_rtattr(sd_netlink_message *m, unsigned short type, const void *data, size_t data_length) {
 169         uint32_t rta_length;
 170         size_t message_length, padding_length;
 171         struct nlmsghdr *new_hdr;
 172         struct rtattr *rta;
 173         char *padding;
 174         unsigned i;
 175         int offset;
 176
 177         assert(m);
 178         assert(m->hdr);
 179         assert(!m->sealed);
 180         assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len);
 181         assert(!data || data_length);
 182
 183         /* get offset of the new attribute */
 184         offset = m->hdr->nlmsg_len;
 185
 186         /* get the size of the new rta attribute (with padding at the end) */
 187         rta_length = RTA_LENGTH(data_length);
 188
 189         /* get the new message size (with padding at the end) */
 190         message_length = offset + RTA_ALIGN(rta_length);
 191
 192         /* realloc to fit the new attribute */
 193         new_hdr = realloc(m->hdr, message_length);
 194         if (!new_hdr)
 195                 return -ENOMEM;
 196         m->hdr = new_hdr;
 197
 198         /* get pointer to the attribute we are about to add */
 199         rta = (struct rtattr *) ((uint8_t *) m->hdr + offset);
 200
 201         /* if we are inside containers, extend them */
 202         for (i = 0; i < m->n_containers; i++)
 203                 GET_CONTAINER(m, i)->rta_len += message_length - offset;
 204
 205         /* fill in the attribute */
 206         rta->rta_type = type;
 207         rta->rta_len = rta_length;
 208         if (data)
 209                 /* we don't deal with the case where the user lies about the type
 210                  * and gives us too little data (so don't do that)
 211                  */
 212                 padding = mempcpy(RTA_DATA(rta), data, data_length);
 213
 214         else
 215                 /* if no data was passed, make sure we still initialize the padding
 216                    note that we can have data_length > 0 (used by some containers) */
 217                 padding = RTA_DATA(rta);
 218
 219         /* make sure also the padding at the end of the message is initialized */
 220         padding_length = (uint8_t*)m->hdr + message_length - (uint8_t*)padding;
 221         memzero(padding, padding_length);
 222
 223         /* update message size */
 224         m->hdr->nlmsg_len = message_length;
 225
 226         return offset;
 227 }
 228
 229 static int message_attribute_has_type(sd_netlink_message *m, size_t *out_size, uint16_t attribute_type, uint16_t data_type) {
 230         const NLType *type;
 231         int r;
 232
 233         assert(m);
 234
 235         r = type_system_get_type(m->containers[m->n_containers].type_system, &type, attribute_type);
 236         if (r < 0)
 237                 return r;
 238
 239         if (type_get_type(type) != data_type)
 240                 return -EINVAL;
 241
 242         if (out_size)
 243                 *out_size = type_get_size(type);
 244         return 0;
 245 }
 246
 247 int sd_netlink_message_append_string(sd_netlink_message *m, unsigned short type, const char *data) {
 248         size_t length, size;
 249         int r;
 250
 251         assert_return(m, -EINVAL);
 252         assert_return(!m->sealed, -EPERM);
 253         assert_return(data, -EINVAL);
 254
 255         r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_STRING);
 256         if (r < 0)
 257                 return r;
 258
 259         if (size) {
 260                 length = strnlen(data, size+1);
 261                 if (length > size)
 262                         return -EINVAL;
 263         } else
 264                 length = strlen(data);
 265
 266         r = add_rtattr(m, type, data, length + 1);
 267         if (r < 0)
 268                 return r;
 269
 270         return 0;
 271 }
 272
 273 int sd_netlink_message_append_flag(sd_netlink_message *m, unsigned short type) {
 274         size_t size;
 275         int r;
 276
 277         assert_return(m, -EINVAL);
 278         assert_return(!m->sealed, -EPERM);
 279
 280         r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_FLAG);
 281         if (r < 0)
 282                 return r;
 283
 284         r = add_rtattr(m, type, NULL, 0);
 285         if (r < 0)
 286                 return r;
 287
 288         return 0;
 289 }
 290
 291 int sd_netlink_message_append_u8(sd_netlink_message *m, unsigned short type, uint8_t data) {
 292         int r;
 293
 294         assert_return(m, -EINVAL);
 295         assert_return(!m->sealed, -EPERM);
 296
 297         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U8);
 298         if (r < 0)
 299                 return r;
 300
 301         r = add_rtattr(m, type, &data, sizeof(uint8_t));
 302         if (r < 0)
 303                 return r;
 304
 305         return 0;
 306 }
 307
 308
 309 int sd_netlink_message_append_u16(sd_netlink_message *m, unsigned short type, uint16_t data) {
 310         int r;
 311
 312         assert_return(m, -EINVAL);
 313         assert_return(!m->sealed, -EPERM);
 314
 315         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U16);
 316         if (r < 0)
 317                 return r;
 318
 319         r = add_rtattr(m, type, &data, sizeof(uint16_t));
 320         if (r < 0)
 321                 return r;
 322
 323         return 0;
 324 }
 325
 326 int sd_netlink_message_append_u32(sd_netlink_message *m, unsigned short type, uint32_t data) {
 327         int r;
 328
 329         assert_return(m, -EINVAL);
 330         assert_return(!m->sealed, -EPERM);
 331
 332         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U32);
 333         if (r < 0)
 334                 return r;
 335
 336         r = add_rtattr(m, type, &data, sizeof(uint32_t));
 337         if (r < 0)
 338                 return r;
 339
 340         return 0;
 341 }
 342
 343 int sd_netlink_message_append_data(sd_netlink_message *m, unsigned short type, const void *data, size_t len) {
 344         int r;
 345
 346         assert_return(m, -EINVAL);
 347         assert_return(!m->sealed, -EPERM);
 348
 349         r = add_rtattr(m, type, data, len);
 350         if (r < 0)
 351                 return r;
 352
 353         return 0;
 354 }
 355
 356 int sd_netlink_message_append_in_addr(sd_netlink_message *m, unsigned short type, const struct in_addr *data) {
 357         int r;
 358
 359         assert_return(m, -EINVAL);
 360         assert_return(!m->sealed, -EPERM);
 361         assert_return(data, -EINVAL);
 362
 363         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
 364         if (r < 0)
 365                 return r;
 366
 367         r = add_rtattr(m, type, data, sizeof(struct in_addr));
 368         if (r < 0)
 369                 return r;
 370
 371         return 0;
 372 }
 373
 374 int sd_netlink_message_append_in6_addr(sd_netlink_message *m, unsigned short type, const struct in6_addr *data) {
 375         int r;
 376
 377         assert_return(m, -EINVAL);
 378         assert_return(!m->sealed, -EPERM);
 379         assert_return(data, -EINVAL);
 380
 381         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
 382         if (r < 0)
 383                 return r;
 384
 385         r = add_rtattr(m, type, data, sizeof(struct in6_addr));
 386         if (r < 0)
 387                 return r;
 388
 389         return 0;
 390 }
 391
 392 int sd_netlink_message_append_ether_addr(sd_netlink_message *m, unsigned short type, const struct ether_addr *data) {
 393         int r;
 394
 395         assert_return(m, -EINVAL);
 396         assert_return(!m->sealed, -EPERM);
 397         assert_return(data, -EINVAL);
 398
 399         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
 400         if (r < 0)
 401                 return r;
 402
 403         r = add_rtattr(m, type, data, ETH_ALEN);
 404         if (r < 0)
 405                 return r;
 406
 407         return 0;
 408 }
 409
 410 int sd_netlink_message_append_cache_info(sd_netlink_message *m, unsigned short type, const struct ifa_cacheinfo *info) {
 411         int r;
 412
 413         assert_return(m, -EINVAL);
 414         assert_return(!m->sealed, -EPERM);
 415         assert_return(info, -EINVAL);
 416
 417         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_CACHE_INFO);
 418         if (r < 0)
 419                 return r;
 420
 421         r = add_rtattr(m, type, info, sizeof(struct ifa_cacheinfo));
 422         if (r < 0)
 423                 return r;
 424
 425         return 0;
 426 }
 427
 428 int sd_netlink_message_open_container(sd_netlink_message *m, unsigned short type) {
 429         size_t size;
 430         int r;
 431
 432         assert_return(m, -EINVAL);
 433         assert_return(!m->sealed, -EPERM);
 434         assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -ERANGE);
 435
 436         r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_NESTED);
 437         if (r < 0) {
 438                 const NLTypeSystemUnion *type_system_union;
 439                 int family;
 440
 441                 r = message_attribute_has_type(m, &size, type, NETLINK_TYPE_UNION);
 442                 if (r < 0)
 443                         return r;
 444
 445                 r = sd_rtnl_message_get_family(m, &family);
 446                 if (r < 0)
 447                         return r;
 448
 449                 r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
 450                 if (r < 0)
 451                         return r;
 452
 453                 r = type_system_union_protocol_get_type_system(type_system_union,
 454                                                                &m->containers[m->n_containers + 1].type_system,
 455                                                                family);
 456                 if (r < 0)
 457                         return r;
 458         } else {
 459                 r = type_system_get_type_system(m->containers[m->n_containers].type_system,
 460                                                 &m->containers[m->n_containers + 1].type_system,
 461                                                 type);
 462                 if (r < 0)
 463                         return r;
 464         }
 465
 466         r = add_rtattr(m, type | NLA_F_NESTED, NULL, size);
 467         if (r < 0)
 468                 return r;
 469
 470         m->containers[m->n_containers++].offset = r;
 471
 472         return 0;
 473 }
 474
 475 int sd_netlink_message_open_container_union(sd_netlink_message *m, unsigned short type, const char *key) {
 476         const NLTypeSystemUnion *type_system_union;
 477         int r;
 478
 479         assert_return(m, -EINVAL);
 480         assert_return(!m->sealed, -EPERM);
 481
 482         r = type_system_get_type_system_union(m->containers[m->n_containers].type_system, &type_system_union, type);
 483         if (r < 0)
 484                 return r;
 485
 486         r = type_system_union_get_type_system(type_system_union,
 487                                               &m->containers[m->n_containers + 1].type_system,
 488                                               key);
 489         if (r < 0)
 490                 return r;
 491
 492         r = sd_netlink_message_append_string(m, type_system_union->match, key);
 493         if (r < 0)
 494                 return r;
 495
 496         /* do we evere need non-null size */
 497         r = add_rtattr(m, type | NLA_F_NESTED, NULL, 0);
 498         if (r < 0)
 499                 return r;
 500
 501         m->containers[m->n_containers++].offset = r;
 502
 503         return 0;
 504 }
 505
 506
 507 int sd_netlink_message_close_container(sd_netlink_message *m) {
 508         assert_return(m, -EINVAL);
 509         assert_return(!m->sealed, -EPERM);
 510         assert_return(m->n_containers > 0, -EINVAL);
 511
 512         m->containers[m->n_containers].type_system = NULL;
 513         m->n_containers--;
 514
 515         return 0;
 516 }
 517
 518 static int netlink_message_read_internal(sd_netlink_message *m, unsigned short type, void **data, bool *net_byteorder) {
 519         struct netlink_attribute *attribute;
 520         struct rtattr *rta;
 521
 522         assert_return(m, -EINVAL);
 523         assert_return(m->sealed, -EPERM);
 524         assert_return(data, -EINVAL);
 525         assert(m->n_containers < RTNL_CONTAINER_DEPTH);
 526         assert(m->containers[m->n_containers].attributes);
 527         assert(type < m->containers[m->n_containers].n_attributes);
 528
 529         attribute = &m->containers[m->n_containers].attributes[type];
 530
 531         if (!attribute->offset)
 532                 return -ENODATA;
 533
 534         rta = (struct rtattr*)((uint8_t *) m->hdr + attribute->offset);
 535
 536         *data = RTA_DATA(rta);
 537
 538         if (net_byteorder)
 539                 *net_byteorder = attribute->net_byteorder;
 540
 541         return RTA_PAYLOAD(rta);
 542 }
 543
 544 int sd_netlink_message_read_string(sd_netlink_message *m, unsigned short type, const char **data) {
 545         int r;
 546         void *attr_data;
 547
 548         assert_return(m, -EINVAL);
 549
 550         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_STRING);
 551         if (r < 0)
 552                 return r;
 553
 554         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 555         if (r < 0)
 556                 return r;
 557         else if (strnlen(attr_data, r) >= (size_t) r)
 558                 return -EIO;
 559
 560         if (data)
 561                 *data = (const char *) attr_data;
 562
 563         return 0;
 564 }
 565
 566 int sd_netlink_message_read_u8(sd_netlink_message *m, unsigned short type, uint8_t *data) {
 567         int r;
 568         void *attr_data;
 569
 570         assert_return(m, -EINVAL);
 571
 572         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U8);
 573         if (r < 0)
 574                 return r;
 575
 576         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 577         if (r < 0)
 578                 return r;
 579         else if ((size_t) r < sizeof(uint8_t))
 580                 return -EIO;
 581
 582         if (data)
 583                 *data = *(uint8_t *) attr_data;
 584
 585         return 0;
 586 }
 587
 588 int sd_netlink_message_read_u16(sd_netlink_message *m, unsigned short type, uint16_t *data) {
 589         void *attr_data;
 590         bool net_byteorder;
 591         int r;
 592
 593         assert_return(m, -EINVAL);
 594
 595         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U16);
 596         if (r < 0)
 597                 return r;
 598
 599         r = netlink_message_read_internal(m, type, &attr_data, &net_byteorder);
 600         if (r < 0)
 601                 return r;
 602         else if ((size_t) r < sizeof(uint16_t))
 603                 return -EIO;
 604
 605         if (data) {
 606                 if (net_byteorder)
 607                         *data = be16toh(*(uint16_t *) attr_data);
 608                 else
 609                         *data = *(uint16_t *) attr_data;
 610         }
 611
 612         return 0;
 613 }
 614
 615 int sd_netlink_message_read_u32(sd_netlink_message *m, unsigned short type, uint32_t *data) {
 616         void *attr_data;
 617         bool net_byteorder;
 618         int r;
 619
 620         assert_return(m, -EINVAL);
 621
 622         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_U32);
 623         if (r < 0)
 624                 return r;
 625
 626         r = netlink_message_read_internal(m, type, &attr_data, &net_byteorder);
 627         if (r < 0)
 628                 return r;
 629         else if ((size_t)r < sizeof(uint32_t))
 630                 return -EIO;
 631
 632         if (data) {
 633                 if (net_byteorder)
 634                         *data = be32toh(*(uint32_t *) attr_data);
 635                 else
 636                         *data = *(uint32_t *) attr_data;
 637         }
 638
 639         return 0;
 640 }
 641
 642 int sd_netlink_message_read_ether_addr(sd_netlink_message *m, unsigned short type, struct ether_addr *data) {
 643         int r;
 644         void *attr_data;
 645
 646         assert_return(m, -EINVAL);
 647
 648         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_ETHER_ADDR);
 649         if (r < 0)
 650                 return r;
 651
 652         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 653         if (r < 0)
 654                 return r;
 655         else if ((size_t)r < sizeof(struct ether_addr))
 656                 return -EIO;
 657
 658         if (data)
 659                 memcpy(data, attr_data, sizeof(struct ether_addr));
 660
 661         return 0;
 662 }
 663
 664 int sd_netlink_message_read_cache_info(sd_netlink_message *m, unsigned short type, struct ifa_cacheinfo *info) {
 665         int r;
 666         void *attr_data;
 667
 668         assert_return(m, -EINVAL);
 669
 670         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_CACHE_INFO);
 671         if (r < 0)
 672                 return r;
 673
 674         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 675         if (r < 0)
 676                 return r;
 677         else if ((size_t)r < sizeof(struct ifa_cacheinfo))
 678                 return -EIO;
 679
 680         if (info)
 681                 memcpy(info, attr_data, sizeof(struct ifa_cacheinfo));
 682
 683         return 0;
 684 }
 685
 686 int sd_netlink_message_read_in_addr(sd_netlink_message *m, unsigned short type, struct in_addr *data) {
 687         int r;
 688         void *attr_data;
 689
 690         assert_return(m, -EINVAL);
 691
 692         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
 693         if (r < 0)
 694                 return r;
 695
 696         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 697         if (r < 0)
 698                 return r;
 699         else if ((size_t)r < sizeof(struct in_addr))
 700                 return -EIO;
 701
 702         if (data)
 703                 memcpy(data, attr_data, sizeof(struct in_addr));
 704
 705         return 0;
 706 }
 707
 708 int sd_netlink_message_read_in6_addr(sd_netlink_message *m, unsigned short type, struct in6_addr *data) {
 709         int r;
 710         void *attr_data;
 711
 712         assert_return(m, -EINVAL);
 713
 714         r = message_attribute_has_type(m, NULL, type, NETLINK_TYPE_IN_ADDR);
 715         if (r < 0)
 716                 return r;
 717
 718         r = netlink_message_read_internal(m, type, &attr_data, NULL);
 719         if (r < 0)
 720                 return r;
 721         else if ((size_t)r < sizeof(struct in6_addr))
 722                 return -EIO;
 723
 724         if (data)
 725                 memcpy(data, attr_data, sizeof(struct in6_addr));
 726
 727         return 0;
 728 }
 729
 730 static int netlink_container_parse(sd_netlink_message *m,
 731                                    struct netlink_container *container,
 732                                    int count,
 733                                    struct rtattr *rta,
 734                                    unsigned int rt_len) {
 735         _cleanup_free_ struct netlink_attribute *attributes = NULL;
 736
 737         attributes = new0(struct netlink_attribute, count);
 738         if (!attributes)
 739                 return -ENOMEM;
 740
 741         for (; RTA_OK(rta, rt_len); rta = RTA_NEXT(rta, rt_len)) {
 742                 unsigned short type;
 743
 744                 type = RTA_TYPE(rta);
 745
 746                 /* if the kernel is newer than the headers we used
 747                    when building, we ignore out-of-range attributes */
 748                 if (type >= count)
 749                         continue;
 750
 751                 if (attributes[type].offset)
 752                         log_debug("rtnl: message parse - overwriting repeated attribute");
 753
 754                 attributes[type].offset = (uint8_t *) rta - (uint8_t *) m->hdr;
 755                 attributes[type].nested = RTA_FLAGS(rta) & NLA_F_NESTED;
 756                 attributes[type].net_byteorder = RTA_FLAGS(rta) & NLA_F_NET_BYTEORDER;
 757         }
 758
 759         container->attributes = attributes;
 760         attributes = NULL;
 761         container->n_attributes = count;
 762
 763         return 0;
 764 }
 765
 766 int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short type_id) {
 767         const NLType *nl_type;
 768         const NLTypeSystem *type_system;
 769         void *container;
 770         uint16_t type;
 771         size_t size;
 772         int r;
 773
 774         assert_return(m, -EINVAL);
 775         assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
 776
 777         r = type_system_get_type(m->containers[m->n_containers].type_system,
 778                                  &nl_type,
 779                                  type_id);
 780         if (r < 0)
 781                 return r;
 782
 783         type = type_get_type(nl_type);
 784
 785         if (type == NETLINK_TYPE_NESTED) {
 786                 r = type_system_get_type_system(m->containers[m->n_containers].type_system,
 787                                                 &type_system,
 788                                                 type_id);
 789                 if (r < 0)
 790                         return r;
 791         } else if (type == NETLINK_TYPE_UNION) {
 792                 const NLTypeSystemUnion *type_system_union;
 793
 794                 r = type_system_get_type_system_union(m->containers[m->n_containers].type_system,
 795                                                       &type_system_union,
 796                                                       type_id);
 797                 if (r < 0)
 798                         return r;
 799
 800                 switch (type_system_union->match_type) {
 801                 case NL_MATCH_SIBLING:
 802                 {
 803                         const char *key;
 804
 805                         r = sd_netlink_message_read_string(m, type_system_union->match, &key);
 806                         if (r < 0)
 807                                 return r;
 808
 809                         r = type_system_union_get_type_system(type_system_union,
 810                                                               &type_system,
 811                                                               key);
 812                         if (r < 0)
 813                                 return r;
 814
 815                         break;
 816                 }
 817                 case NL_MATCH_PROTOCOL:
 818                 {
 819                         int family;
 820
 821                         r = sd_rtnl_message_get_family(m, &family);
 822                         if (r < 0)
 823                                 return r;
 824
 825                         r = type_system_union_protocol_get_type_system(type_system_union,
 826                                                                        &type_system,
 827                                                                        family);
 828                         if (r < 0)
 829                                 return r;
 830
 831                         break;
 832                 }
 833                 default:
 834                         assert_not_reached("sd-netlink: invalid type system union type");
 835                 }
 836         } else
 837                 return -EINVAL;
 838
 839         r = netlink_message_read_internal(m, type_id, &container, NULL);
 840         if (r < 0)
 841                 return r;
 842         else
 843                 size = (size_t)r;
 844
 845         m->n_containers++;
 846
 847         r = netlink_container_parse(m,
 848                                     &m->containers[m->n_containers],
 849                                     type_system_get_count(type_system),
 850                                     container,
 851                                     size);
 852         if (r < 0) {
 853                 m->n_containers--;
 854                 return r;
 855         }
 856
 857         m->containers[m->n_containers].type_system = type_system;
 858
 859         return 0;
 860 }
 861
 862 int sd_netlink_message_exit_container(sd_netlink_message *m) {
 863         assert_return(m, -EINVAL);
 864         assert_return(m->sealed, -EINVAL);
 865         assert_return(m->n_containers > 0, -EINVAL);
 866
 867         m->containers[m->n_containers].attributes = mfree(m->containers[m->n_containers].attributes);
 868         m->containers[m->n_containers].type_system = NULL;
 869
 870         m->n_containers--;
 871
 872         return 0;
 873 }
 874
 875 uint32_t rtnl_message_get_serial(sd_netlink_message *m) {
 876         assert(m);
 877         assert(m->hdr);
 878
 879         return m->hdr->nlmsg_seq;
 880 }
 881
 882 int sd_netlink_message_is_error(sd_netlink_message *m) {
 883         assert_return(m, 0);
 884         assert_return(m->hdr, 0);
 885
 886         return m->hdr->nlmsg_type == NLMSG_ERROR;
 887 }
 888
 889 int sd_netlink_message_get_errno(sd_netlink_message *m) {
 890         struct nlmsgerr *err;
 891
 892         assert_return(m, -EINVAL);
 893         assert_return(m->hdr, -EINVAL);
 894
 895         if (!sd_netlink_message_is_error(m))
 896                 return 0;
 897
 898         err = NLMSG_DATA(m->hdr);
 899
 900         return err->error;
 901 }
 902
 903 int sd_netlink_message_rewind(sd_netlink_message *m) {
 904         const NLType *nl_type;
 905         uint16_t type;
 906         size_t size;
 907         unsigned i;
 908         int r;
 909
 910         assert_return(m, -EINVAL);
 911
 912         /* don't allow appending to message once parsed */
 913         if (!m->sealed)
 914                 rtnl_message_seal(m);
 915
 916         for (i = 1; i <= m->n_containers; i++)
 917                 m->containers[i].attributes = mfree(m->containers[i].attributes);
 918
 919         m->n_containers = 0;
 920
 921         if (m->containers[0].attributes)
 922                 /* top-level attributes have already been parsed */
 923                 return 0;
 924
 925         assert(m->hdr);
 926
 927         r = type_system_get_type(&type_system_root, &nl_type, m->hdr->nlmsg_type);
 928         if (r < 0)
 929                 return r;
 930
 931         type = type_get_type(nl_type);
 932         size = type_get_size(nl_type);
 933
 934         if (type == NETLINK_TYPE_NESTED) {
 935                 const NLTypeSystem *type_system;
 936
 937                 type_get_type_system(nl_type, &type_system);
 938
 939                 m->containers[0].type_system = type_system;
 940
 941                 r = netlink_container_parse(m,
 942                                             &m->containers[m->n_containers],
 943                                             type_system_get_count(type_system),
 944                                             (struct rtattr*)((uint8_t*)NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)),
 945                                             NLMSG_PAYLOAD(m->hdr, size));
 946                 if (r < 0)
 947                         return r;
 948         }
 949
 950         return 0;
 951 }
 952
 953 void rtnl_message_seal(sd_netlink_message *m) {
 954         assert(m);
 955         assert(!m->sealed);
 956
 957         m->sealed = true;
 958 }
 959
 960 sd_netlink_message *sd_netlink_message_next(sd_netlink_message *m) {
 961         assert_return(m, NULL);
 962
 963         return m->next;
 964 }