lib/libnetlink.c

   1 /*
   2  * libnetlink.c RTnetlink service routines.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <syslog.h>
  17 #include <fcntl.h>
  18 #include <net/if_arp.h>
  19 #include <sys/socket.h>
  20 #include <netinet/in.h>
  21 #include <string.h>
  22 #include <errno.h>
  23 #include <time.h>
  24 #include <sys/uio.h>
  25
  26 #include "libnetlink.h"
  27
  28 int rcvbuf = 1024 * 1024;
  29
  30 void rtnl_close(struct rtnl_handle *rth)
  31 {
  32         if (rth->fd >= 0) {
  33                 close(rth->fd);
  34                 rth->fd = -1;
  35         }
  36 }
  37
  38 int rtnl_open_byproto(struct rtnl_handle *rth, unsigned subscriptions,
  39                       int protocol)
  40 {
  41         socklen_t addr_len;
  42         int sndbuf = 32768;
  43
  44         memset(rth, 0, sizeof(*rth));
  45
  46         rth->proto = protocol;
  47         rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
  48         if (rth->fd < 0) {
  49                 perror("Cannot open netlink socket");
  50                 return -1;
  51         }
  52
  53         if (setsockopt(rth->fd,SOL_SOCKET,SO_SNDBUF,&sndbuf,sizeof(sndbuf)) < 0) {
  54                 perror("SO_SNDBUF");
  55                 return -1;
  56         }
  57
  58         if (setsockopt(rth->fd,SOL_SOCKET,SO_RCVBUF,&rcvbuf,sizeof(rcvbuf)) < 0) {
  59                 perror("SO_RCVBUF");
  60                 return -1;
  61         }
  62
  63         memset(&rth->local, 0, sizeof(rth->local));
  64         rth->local.nl_family = AF_NETLINK;
  65         rth->local.nl_groups = subscriptions;
  66
  67         if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) {
  68                 perror("Cannot bind netlink socket");
  69                 return -1;
  70         }
  71         addr_len = sizeof(rth->local);
  72         if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {
  73                 perror("Cannot getsockname");
  74                 return -1;
  75         }
  76         if (addr_len != sizeof(rth->local)) {
  77                 fprintf(stderr, "Wrong address length %d\n", addr_len);
  78                 return -1;
  79         }
  80         if (rth->local.nl_family != AF_NETLINK) {
  81                 fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family);
  82                 return -1;
  83         }
  84         rth->seq = time(NULL);
  85         return 0;
  86 }
  87
  88 int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
  89 {
  90         return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
  91 }
  92
  93 int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
  94 {
  95         return rtnl_wilddump_req_filter(rth, family, type, RTEXT_FILTER_VF);
  96 }
  97
  98 int rtnl_wilddump_req_filter(struct rtnl_handle *rth, int family, int type,
  99                             __u32 filt_mask)
 100 {
 101         struct {
 102                 struct nlmsghdr nlh;
 103                 struct ifinfomsg ifm;
 104                 /* attribute has to be NLMSG aligned */
 105                 struct rtattr ext_req __attribute__ ((aligned(NLMSG_ALIGNTO)));
 106                 __u32 ext_filter_mask;
 107         } req;
 108
 109         memset(&req, 0, sizeof(req));
 110         req.nlh.nlmsg_len = sizeof(req);
 111         req.nlh.nlmsg_type = type;
 112         req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 113         req.nlh.nlmsg_pid = 0;
 114         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 115         req.ifm.ifi_family = family;
 116
 117         req.ext_req.rta_type = IFLA_EXT_MASK;
 118         req.ext_req.rta_len = RTA_LENGTH(sizeof(__u32));
 119         req.ext_filter_mask = filt_mask;
 120
 121         return send(rth->fd, (void*)&req, sizeof(req), 0);
 122 }
 123
 124 int rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 125 {
 126         return send(rth->fd, buf, len, 0);
 127 }
 128
 129 int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len)
 130 {
 131         struct nlmsghdr *h;
 132         int status;
 133         char resp[1024];
 134
 135         status = send(rth->fd, buf, len, 0);
 136         if (status < 0)
 137                 return status;
 138
 139         /* Check for immediate errors */
 140         status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
 141         if (status < 0) {
 142                 if (errno == EAGAIN)
 143                         return 0;
 144                 return -1;
 145         }
 146
 147         for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, status);
 148              h = NLMSG_NEXT(h, status)) {
 149                 if (h->nlmsg_type == NLMSG_ERROR) {
 150                         struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 151                         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 152                                 fprintf(stderr, "ERROR truncated\n");
 153                         else
 154                                 errno = -err->error;
 155                         return -1;
 156                 }
 157         }
 158
 159         return 0;
 160 }
 161
 162 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 163 {
 164         struct nlmsghdr nlh;
 165         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 166         struct iovec iov[2] = {
 167                 { .iov_base = &nlh, .iov_len = sizeof(nlh) },
 168                 { .iov_base = req, .iov_len = len }
 169         };
 170         struct msghdr msg = {
 171                 .msg_name = &nladdr,
 172                 .msg_namelen =  sizeof(nladdr),
 173                 .msg_iov = iov,
 174                 .msg_iovlen = 2,
 175         };
 176
 177         nlh.nlmsg_len = NLMSG_LENGTH(len);
 178         nlh.nlmsg_type = type;
 179         nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 180         nlh.nlmsg_pid = 0;
 181         nlh.nlmsg_seq = rth->dump = ++rth->seq;
 182
 183         return sendmsg(rth->fd, &msg, 0);
 184 }
 185
 186 int rtnl_dump_filter_l(struct rtnl_handle *rth,
 187                        const struct rtnl_dump_filter_arg *arg)
 188 {
 189         struct sockaddr_nl nladdr;
 190         struct iovec iov;
 191         struct msghdr msg = {
 192                 .msg_name = &nladdr,
 193                 .msg_namelen = sizeof(nladdr),
 194                 .msg_iov = &iov,
 195                 .msg_iovlen = 1,
 196         };
 197         char buf[16384];
 198         int dump_intr = 0;
 199
 200         iov.iov_base = buf;
 201         while (1) {
 202                 int status;
 203                 const struct rtnl_dump_filter_arg *a;
 204                 int found_done = 0;
 205                 int msglen = 0;
 206
 207                 iov.iov_len = sizeof(buf);
 208                 status = recvmsg(rth->fd, &msg, 0);
 209
 210                 if (status < 0) {
 211                         if (errno == EINTR || errno == EAGAIN)
 212                                 continue;
 213                         fprintf(stderr, "netlink receive error %s (%d)\n",
 214                                 strerror(errno), errno);
 215                         return -1;
 216                 }
 217
 218                 if (status == 0) {
 219                         fprintf(stderr, "EOF on netlink\n");
 220                         return -1;
 221                 }
 222
 223                 for (a = arg; a->filter; a++) {
 224                         struct nlmsghdr *h = (struct nlmsghdr*)buf;
 225                         msglen = status;
 226
 227                         while (NLMSG_OK(h, msglen)) {
 228                                 int err;
 229
 230                                 if (nladdr.nl_pid != 0 ||
 231                                     h->nlmsg_pid != rth->local.nl_pid ||
 232                                     h->nlmsg_seq != rth->dump)
 233                                         goto skip_it;
 234
 235                                 if (h->nlmsg_flags & NLM_F_DUMP_INTR)
 236                                         dump_intr = 1;
 237
 238                                 if (h->nlmsg_type == NLMSG_DONE) {
 239                                         found_done = 1;
 240                                         break; /* process next filter */
 241                                 }
 242                                 if (h->nlmsg_type == NLMSG_ERROR) {
 243                                         struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 244                                         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 245                                                 fprintf(stderr,
 246                                                         "ERROR truncated\n");
 247                                         } else {
 248                                                 errno = -err->error;
 249                                                 if (rth->proto == NETLINK_SOCK_DIAG &&
 250                                                     errno == ENOENT)
 251                                                         return -1;
 252
 253                                                 perror("RTNETLINK answers");
 254                                         }
 255                                         return -1;
 256                                 }
 257                                 err = a->filter(&nladdr, h, a->arg1);
 258                                 if (err < 0)
 259                                         return err;
 260
 261 skip_it:
 262                                 h = NLMSG_NEXT(h, msglen);
 263                         }
 264                 }
 265
 266                 if (found_done) {
 267                         if (dump_intr)
 268                                 fprintf(stderr,
 269                                         "Dump was interrupted and may be inconsistent.\n");
 270                         return 0;
 271                 }
 272
 273                 if (msg.msg_flags & MSG_TRUNC) {
 274                         fprintf(stderr, "Message truncated\n");
 275                         continue;
 276                 }
 277                 if (msglen) {
 278                         fprintf(stderr, "!!!Remnant of size %d\n", msglen);
 279                         exit(1);
 280                 }
 281         }
 282 }
 283
 284 int rtnl_dump_filter(struct rtnl_handle *rth,
 285                      rtnl_filter_t filter,
 286                      void *arg1)
 287 {
 288         const struct rtnl_dump_filter_arg a[2] = {
 289                 { .filter = filter, .arg1 = arg1, },
 290                 { .filter = NULL,   .arg1 = NULL, },
 291         };
 292
 293         return rtnl_dump_filter_l(rth, a);
 294 }
 295
 296 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
 297               unsigned groups, struct nlmsghdr *answer)
 298 {
 299         int status;
 300         unsigned seq;
 301         struct nlmsghdr *h;
 302         struct sockaddr_nl nladdr;
 303         struct iovec iov = {
 304                 .iov_base = (void*) n,
 305                 .iov_len = n->nlmsg_len
 306         };
 307         struct msghdr msg = {
 308                 .msg_name = &nladdr,
 309                 .msg_namelen = sizeof(nladdr),
 310                 .msg_iov = &iov,
 311                 .msg_iovlen = 1,
 312         };
 313         char   buf[16384];
 314
 315         memset(&nladdr, 0, sizeof(nladdr));
 316         nladdr.nl_family = AF_NETLINK;
 317         nladdr.nl_pid = peer;
 318         nladdr.nl_groups = groups;
 319
 320         n->nlmsg_seq = seq = ++rtnl->seq;
 321
 322         if (answer == NULL)
 323                 n->nlmsg_flags |= NLM_F_ACK;
 324
 325         status = sendmsg(rtnl->fd, &msg, 0);
 326
 327         if (status < 0) {
 328                 perror("Cannot talk to rtnetlink");
 329                 return -1;
 330         }
 331
 332         memset(buf,0,sizeof(buf));
 333
 334         iov.iov_base = buf;
 335
 336         while (1) {
 337                 iov.iov_len = sizeof(buf);
 338                 status = recvmsg(rtnl->fd, &msg, 0);
 339
 340                 if (status < 0) {
 341                         if (errno == EINTR || errno == EAGAIN)
 342                                 continue;
 343                         fprintf(stderr, "netlink receive error %s (%d)\n",
 344                                 strerror(errno), errno);
 345                         return -1;
 346                 }
 347                 if (status == 0) {
 348                         fprintf(stderr, "EOF on netlink\n");
 349                         return -1;
 350                 }
 351                 if (msg.msg_namelen != sizeof(nladdr)) {
 352                         fprintf(stderr, "sender address length == %d\n", msg.msg_namelen);
 353                         exit(1);
 354                 }
 355                 for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
 356                         int len = h->nlmsg_len;
 357                         int l = len - sizeof(*h);
 358
 359                         if (l < 0 || len>status) {
 360                                 if (msg.msg_flags & MSG_TRUNC) {
 361                                         fprintf(stderr, "Truncated message\n");
 362                                         return -1;
 363                                 }
 364                                 fprintf(stderr, "!!!malformed message: len=%d\n", len);
 365                                 exit(1);
 366                         }
 367
 368                         if (nladdr.nl_pid != peer ||
 369                             h->nlmsg_pid != rtnl->local.nl_pid ||
 370                             h->nlmsg_seq != seq) {
 371                                 /* Don't forget to skip that message. */
 372                                 status -= NLMSG_ALIGN(len);
 373                                 h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 374                                 continue;
 375                         }
 376
 377                         if (h->nlmsg_type == NLMSG_ERROR) {
 378                                 struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 379                                 if (l < sizeof(struct nlmsgerr)) {
 380                                         fprintf(stderr, "ERROR truncated\n");
 381                                 } else {
 382                                         if (!err->error) {
 383                                                 if (answer)
 384                                                         memcpy(answer, h, h->nlmsg_len);
 385                                                 return 0;
 386                                         }
 387
 388                                         fprintf(stderr, "RTNETLINK answers: %s\n", strerror(-err->error));
 389                                         errno = -err->error;
 390                                 }
 391                                 return -1;
 392                         }
 393                         if (answer) {
 394                                 memcpy(answer, h, h->nlmsg_len);
 395                                 return 0;
 396                         }
 397
 398                         fprintf(stderr, "Unexpected reply!!!\n");
 399
 400                         status -= NLMSG_ALIGN(len);
 401                         h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 402                 }
 403                 if (msg.msg_flags & MSG_TRUNC) {
 404                         fprintf(stderr, "Message truncated\n");
 405                         continue;
 406                 }
 407                 if (status) {
 408                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 409                         exit(1);
 410                 }
 411         }
 412 }
 413
 414 int rtnl_listen(struct rtnl_handle *rtnl,
 415                 rtnl_filter_t handler,
 416                 void *jarg)
 417 {
 418         int status;
 419         struct nlmsghdr *h;
 420         struct sockaddr_nl nladdr;
 421         struct iovec iov;
 422         struct msghdr msg = {
 423                 .msg_name = &nladdr,
 424                 .msg_namelen = sizeof(nladdr),
 425                 .msg_iov = &iov,
 426                 .msg_iovlen = 1,
 427         };
 428         char   buf[16384];
 429
 430         memset(&nladdr, 0, sizeof(nladdr));
 431         nladdr.nl_family = AF_NETLINK;
 432         nladdr.nl_pid = 0;
 433         nladdr.nl_groups = 0;
 434
 435         iov.iov_base = buf;
 436         while (1) {
 437                 iov.iov_len = sizeof(buf);
 438                 status = recvmsg(rtnl->fd, &msg, 0);
 439
 440                 if (status < 0) {
 441                         if (errno == EINTR || errno == EAGAIN)
 442                                 continue;
 443                         fprintf(stderr, "netlink receive error %s (%d)\n",
 444                                 strerror(errno), errno);
 445                         if (errno == ENOBUFS)
 446                                 continue;
 447                         return -1;
 448                 }
 449                 if (status == 0) {
 450                         fprintf(stderr, "EOF on netlink\n");
 451                         return -1;
 452                 }
 453                 if (msg.msg_namelen != sizeof(nladdr)) {
 454                         fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen);
 455                         exit(1);
 456                 }
 457                 for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
 458                         int err;
 459                         int len = h->nlmsg_len;
 460                         int l = len - sizeof(*h);
 461
 462                         if (l<0 || len>status) {
 463                                 if (msg.msg_flags & MSG_TRUNC) {
 464                                         fprintf(stderr, "Truncated message\n");
 465                                         return -1;
 466                                 }
 467                                 fprintf(stderr, "!!!malformed message: len=%d\n", len);
 468                                 exit(1);
 469                         }
 470
 471                         err = handler(&nladdr, h, jarg);
 472                         if (err < 0)
 473                                 return err;
 474
 475                         status -= NLMSG_ALIGN(len);
 476                         h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 477                 }
 478                 if (msg.msg_flags & MSG_TRUNC) {
 479                         fprintf(stderr, "Message truncated\n");
 480                         continue;
 481                 }
 482                 if (status) {
 483                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 484                         exit(1);
 485                 }
 486         }
 487 }
 488
 489 int rtnl_from_file(FILE *rtnl, rtnl_filter_t handler,
 490                    void *jarg)
 491 {
 492         int status;
 493         struct sockaddr_nl nladdr;
 494         char   buf[16384];
 495         struct nlmsghdr *h = (void*)buf;
 496
 497         memset(&nladdr, 0, sizeof(nladdr));
 498         nladdr.nl_family = AF_NETLINK;
 499         nladdr.nl_pid = 0;
 500         nladdr.nl_groups = 0;
 501
 502         while (1) {
 503                 int err, len;
 504                 int l;
 505
 506                 status = fread(&buf, 1, sizeof(*h), rtnl);
 507
 508                 if (status < 0) {
 509                         if (errno == EINTR)
 510                                 continue;
 511                         perror("rtnl_from_file: fread");
 512                         return -1;
 513                 }
 514                 if (status == 0)
 515                         return 0;
 516
 517                 len = h->nlmsg_len;
 518                 l = len - sizeof(*h);
 519
 520                 if (l<0 || len>sizeof(buf)) {
 521                         fprintf(stderr, "!!!malformed message: len=%d @%lu\n",
 522                                 len, ftell(rtnl));
 523                         return -1;
 524                 }
 525
 526                 status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
 527
 528                 if (status < 0) {
 529                         perror("rtnl_from_file: fread");
 530                         return -1;
 531                 }
 532                 if (status < l) {
 533                         fprintf(stderr, "rtnl-from_file: truncated message\n");
 534                         return -1;
 535                 }
 536
 537                 err = handler(&nladdr, h, jarg);
 538                 if (err < 0)
 539                         return err;
 540         }
 541 }
 542
 543 int addattr(struct nlmsghdr *n, int maxlen, int type)
 544 {
 545         return addattr_l(n, maxlen, type, NULL, 0);
 546 }
 547
 548 int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data)
 549 {
 550         return addattr_l(n, maxlen, type, &data, sizeof(__u8));
 551 }
 552
 553 int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data)
 554 {
 555         return addattr_l(n, maxlen, type, &data, sizeof(__u16));
 556 }
 557
 558 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
 559 {
 560         return addattr_l(n, maxlen, type, &data, sizeof(__u32));
 561 }
 562
 563 int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data)
 564 {
 565         return addattr_l(n, maxlen, type, &data, sizeof(__u64));
 566 }
 567
 568 int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str)
 569 {
 570         return addattr_l(n, maxlen, type, str, strlen(str)+1);
 571 }
 572
 573 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
 574               int alen)
 575 {
 576         int len = RTA_LENGTH(alen);
 577         struct rtattr *rta;
 578
 579         if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
 580                 fprintf(stderr, "addattr_l ERROR: message exceeded bound of %d\n",maxlen);
 581                 return -1;
 582         }
 583         rta = NLMSG_TAIL(n);
 584         rta->rta_type = type;
 585         rta->rta_len = len;
 586         memcpy(RTA_DATA(rta), data, alen);
 587         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
 588         return 0;
 589 }
 590
 591 int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
 592 {
 593         if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) {
 594                 fprintf(stderr, "addraw_l ERROR: message exceeded bound of %d\n",maxlen);
 595                 return -1;
 596         }
 597
 598         memcpy(NLMSG_TAIL(n), data, len);
 599         memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
 600         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
 601         return 0;
 602 }
 603
 604 struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
 605 {
 606         struct rtattr *nest = NLMSG_TAIL(n);
 607
 608         addattr_l(n, maxlen, type, NULL, 0);
 609         return nest;
 610 }
 611
 612 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
 613 {
 614         nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest;
 615         return n->nlmsg_len;
 616 }
 617
 618 struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
 619                                    const void *data, int len)
 620 {
 621         struct rtattr *start = NLMSG_TAIL(n);
 622
 623         addattr_l(n, maxlen, type, data, len);
 624         addattr_nest(n, maxlen, type);
 625         return start;
 626 }
 627
 628 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
 629 {
 630         struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len);
 631
 632         start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start;
 633         addattr_nest_end(n, nest);
 634         return n->nlmsg_len;
 635 }
 636
 637 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
 638 {
 639         int len = RTA_LENGTH(4);
 640         struct rtattr *subrta;
 641
 642         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 643                 fprintf(stderr,"rta_addattr32: Error! max allowed bound %d exceeded\n",maxlen);
 644                 return -1;
 645         }
 646         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 647         subrta->rta_type = type;
 648         subrta->rta_len = len;
 649         memcpy(RTA_DATA(subrta), &data, 4);
 650         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 651         return 0;
 652 }
 653
 654 int rta_addattr_l(struct rtattr *rta, int maxlen, int type,
 655                   const void *data, int alen)
 656 {
 657         struct rtattr *subrta;
 658         int len = RTA_LENGTH(alen);
 659
 660         if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen) {
 661                 fprintf(stderr,"rta_addattr_l: Error! max allowed bound %d exceeded\n",maxlen);
 662                 return -1;
 663         }
 664         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 665         subrta->rta_type = type;
 666         subrta->rta_len = len;
 667         memcpy(RTA_DATA(subrta), data, alen);
 668         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
 669         return 0;
 670 }
 671
 672 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 673 {
 674         return parse_rtattr_flags(tb, max, rta, len, 0);
 675 }
 676
 677 int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
 678                        int len, unsigned short flags)
 679 {
 680         unsigned short type;
 681
 682         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
 683         while (RTA_OK(rta, len)) {
 684                 type = rta->rta_type & ~flags;
 685                 if ((type <= max) && (!tb[type]))
 686                         tb[type] = rta;
 687                 rta = RTA_NEXT(rta,len);
 688         }
 689         if (len)
 690                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);
 691         return 0;
 692 }
 693
 694 int parse_rtattr_byindex(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 695 {
 696         int i = 0;
 697
 698         memset(tb, 0, sizeof(struct rtattr *) * max);
 699         while (RTA_OK(rta, len)) {
 700                 if (rta->rta_type <= max && i < max)
 701                         tb[i++] = rta;
 702                 rta = RTA_NEXT(rta,len);
 703         }
 704         if (len)
 705                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);
 706         return i;
 707 }
 708
 709 int __parse_rtattr_nested_compat(struct rtattr *tb[], int max, struct rtattr *rta,
 710                                  int len)
 711 {
 712         if (RTA_PAYLOAD(rta) < len)
 713                 return -1;
 714         if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
 715                 rta = RTA_DATA(rta) + RTA_ALIGN(len);
 716                 return parse_rtattr_nested(tb, max, rta);
 717         }
 718         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
 719         return 0;
 720 }