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 <stdbool.h>
  16 #include <unistd.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 #ifndef SOL_NETLINK
  29 #define SOL_NETLINK 270
  30 #endif
  31
  32 #ifndef MIN
  33 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  34 #endif
  35
  36 int rcvbuf = 1024 * 1024;
  37
  38 #ifdef HAVE_LIBMNL
  39 #include <libmnl/libmnl.h>
  40
  41 static const enum mnl_attr_data_type extack_policy[NLMSGERR_ATTR_MAX + 1] = {
  42         [NLMSGERR_ATTR_MSG]     = MNL_TYPE_NUL_STRING,
  43         [NLMSGERR_ATTR_OFFS]    = MNL_TYPE_U32,
  44 };
  45
  46 static int err_attr_cb(const struct nlattr *attr, void *data)
  47 {
  48         const struct nlattr **tb = data;
  49         uint16_t type;
  50
  51         if (mnl_attr_type_valid(attr, NLMSGERR_ATTR_MAX) < 0) {
  52                 fprintf(stderr, "Invalid extack attribute\n");
  53                 return MNL_CB_ERROR;
  54         }
  55
  56         type = mnl_attr_get_type(attr);
  57         if (mnl_attr_validate(attr, extack_policy[type]) < 0) {
  58                 fprintf(stderr, "extack attribute %d failed validation\n",
  59                         type);
  60                 return MNL_CB_ERROR;
  61         }
  62
  63         tb[type] = attr;
  64         return MNL_CB_OK;
  65 }
  66
  67 /* dump netlink extended ack error message */
  68 int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
  69 {
  70         struct nlattr *tb[NLMSGERR_ATTR_MAX + 1] = {};
  71         const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
  72         const struct nlmsghdr *err_nlh = NULL;
  73         unsigned int hlen = sizeof(*err);
  74         const char *msg = NULL;
  75         uint32_t off = 0;
  76
  77         /* no TLVs, nothing to do here */
  78         if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
  79                 return 0;
  80
  81         /* if NLM_F_CAPPED is set then the inner err msg was capped */
  82         if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
  83                 hlen += mnl_nlmsg_get_payload_len(&err->msg);
  84
  85         if (mnl_attr_parse(nlh, hlen, err_attr_cb, tb) != MNL_CB_OK)
  86                 return 0;
  87
  88         if (tb[NLMSGERR_ATTR_MSG])
  89                 msg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]);
  90
  91         if (tb[NLMSGERR_ATTR_OFFS]) {
  92                 off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]);
  93
  94                 if (off > nlh->nlmsg_len) {
  95                         fprintf(stderr,
  96                                 "Invalid offset for NLMSGERR_ATTR_OFFS\n");
  97                         off = 0;
  98                 } else if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
  99                         err_nlh = &err->msg;
 100         }
 101
 102         if (errfn)
 103                 return errfn(msg, off, err_nlh);
 104
 105         if (msg && *msg != '\0') {
 106                 bool is_err = !!err->error;
 107
 108                 fprintf(stderr, "%s: %s",
 109                         is_err ? "Error" : "Warning", msg);
 110                 if (msg[strlen(msg) - 1] != '.')
 111                         fprintf(stderr, ".");
 112                 fprintf(stderr, "\n");
 113
 114                 return is_err ? 1 : 0;
 115         }
 116
 117         return 0;
 118 }
 119 #else
 120 #warning "libmnl required for error support"
 121
 122 /* No extended error ack without libmnl */
 123 int nl_dump_ext_ack(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
 124 {
 125         return 0;
 126 }
 127 #endif
 128
 129 void rtnl_close(struct rtnl_handle *rth)
 130 {
 131         if (rth->fd >= 0) {
 132                 close(rth->fd);
 133                 rth->fd = -1;
 134         }
 135 }
 136
 137 int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions,
 138                       int protocol)
 139 {
 140         socklen_t addr_len;
 141         int sndbuf = 32768;
 142         int one = 1;
 143
 144         memset(rth, 0, sizeof(*rth));
 145
 146         rth->proto = protocol;
 147         rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
 148         if (rth->fd < 0) {
 149                 perror("Cannot open netlink socket");
 150                 return -1;
 151         }
 152
 153         if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF,
 154                        &sndbuf, sizeof(sndbuf)) < 0) {
 155                 perror("SO_SNDBUF");
 156                 return -1;
 157         }
 158
 159         if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF,
 160                        &rcvbuf, sizeof(rcvbuf)) < 0) {
 161                 perror("SO_RCVBUF");
 162                 return -1;
 163         }
 164
 165         /* Older kernels may no support extended ACK reporting */
 166         setsockopt(rth->fd, SOL_NETLINK, NETLINK_EXT_ACK,
 167                    &one, sizeof(one));
 168
 169         memset(&rth->local, 0, sizeof(rth->local));
 170         rth->local.nl_family = AF_NETLINK;
 171         rth->local.nl_groups = subscriptions;
 172
 173         if (bind(rth->fd, (struct sockaddr *)&rth->local,
 174                  sizeof(rth->local)) < 0) {
 175                 perror("Cannot bind netlink socket");
 176                 return -1;
 177         }
 178         addr_len = sizeof(rth->local);
 179         if (getsockname(rth->fd, (struct sockaddr *)&rth->local,
 180                         &addr_len) < 0) {
 181                 perror("Cannot getsockname");
 182                 return -1;
 183         }
 184         if (addr_len != sizeof(rth->local)) {
 185                 fprintf(stderr, "Wrong address length %d\n", addr_len);
 186                 return -1;
 187         }
 188         if (rth->local.nl_family != AF_NETLINK) {
 189                 fprintf(stderr, "Wrong address family %d\n",
 190                         rth->local.nl_family);
 191                 return -1;
 192         }
 193         rth->seq = time(NULL);
 194         return 0;
 195 }
 196
 197 int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions)
 198 {
 199         return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
 200 }
 201
 202 int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
 203 {
 204         return rtnl_wilddump_req_filter(rth, family, type, RTEXT_FILTER_VF);
 205 }
 206
 207 int rtnl_wilddump_req_filter(struct rtnl_handle *rth, int family, int type,
 208                             __u32 filt_mask)
 209 {
 210         struct {
 211                 struct nlmsghdr nlh;
 212                 struct ifinfomsg ifm;
 213                 /* attribute has to be NLMSG aligned */
 214                 struct rtattr ext_req __attribute__ ((aligned(NLMSG_ALIGNTO)));
 215                 __u32 ext_filter_mask;
 216         } req = {
 217                 .nlh.nlmsg_len = sizeof(req),
 218                 .nlh.nlmsg_type = type,
 219                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 220                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 221                 .ifm.ifi_family = family,
 222                 .ext_req.rta_type = IFLA_EXT_MASK,
 223                 .ext_req.rta_len = RTA_LENGTH(sizeof(__u32)),
 224                 .ext_filter_mask = filt_mask,
 225         };
 226
 227         return send(rth->fd, &req, sizeof(req), 0);
 228 }
 229
 230 int rtnl_wilddump_req_filter_fn(struct rtnl_handle *rth, int family, int type,
 231                                 req_filter_fn_t filter_fn)
 232 {
 233         struct {
 234                 struct nlmsghdr nlh;
 235                 struct ifinfomsg ifm;
 236                 char buf[1024];
 237         } req = {
 238                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
 239                 .nlh.nlmsg_type = type,
 240                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 241                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 242                 .ifm.ifi_family = family,
 243         };
 244         int err;
 245
 246         if (!filter_fn)
 247                 return -EINVAL;
 248
 249         err = filter_fn(&req.nlh, sizeof(req));
 250         if (err)
 251                 return err;
 252
 253         return send(rth->fd, &req, req.nlh.nlmsg_len, 0);
 254 }
 255
 256 int rtnl_wilddump_stats_req_filter(struct rtnl_handle *rth, int fam, int type,
 257                                    __u32 filt_mask)
 258 {
 259         struct {
 260                 struct nlmsghdr nlh;
 261                 struct if_stats_msg ifsm;
 262         } req;
 263
 264         memset(&req, 0, sizeof(req));
 265         req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct if_stats_msg));
 266         req.nlh.nlmsg_type = type;
 267         req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 268         req.nlh.nlmsg_pid = 0;
 269         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 270         req.ifsm.family = fam;
 271         req.ifsm.filter_mask = filt_mask;
 272
 273         return send(rth->fd, &req, sizeof(req), 0);
 274 }
 275
 276 int rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 277 {
 278         return send(rth->fd, buf, len, 0);
 279 }
 280
 281 int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len)
 282 {
 283         struct nlmsghdr *h;
 284         int status;
 285         char resp[1024];
 286
 287         status = send(rth->fd, buf, len, 0);
 288         if (status < 0)
 289                 return status;
 290
 291         /* Check for immediate errors */
 292         status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
 293         if (status < 0) {
 294                 if (errno == EAGAIN)
 295                         return 0;
 296                 return -1;
 297         }
 298
 299         for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, status);
 300              h = NLMSG_NEXT(h, status)) {
 301                 if (h->nlmsg_type == NLMSG_ERROR) {
 302                         struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 303
 304                         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 305                                 fprintf(stderr, "ERROR truncated\n");
 306                         else
 307                                 errno = -err->error;
 308                         return -1;
 309                 }
 310         }
 311
 312         return 0;
 313 }
 314
 315 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 316 {
 317         struct nlmsghdr nlh = {
 318                 .nlmsg_len = NLMSG_LENGTH(len),
 319                 .nlmsg_type = type,
 320                 .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 321                 .nlmsg_seq = rth->dump = ++rth->seq,
 322         };
 323         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 324         struct iovec iov[2] = {
 325                 { .iov_base = &nlh, .iov_len = sizeof(nlh) },
 326                 { .iov_base = req, .iov_len = len }
 327         };
 328         struct msghdr msg = {
 329                 .msg_name = &nladdr,
 330                 .msg_namelen = sizeof(nladdr),
 331                 .msg_iov = iov,
 332                 .msg_iovlen = 2,
 333         };
 334
 335         return sendmsg(rth->fd, &msg, 0);
 336 }
 337
 338 int rtnl_dump_request_n(struct rtnl_handle *rth, struct nlmsghdr *n)
 339 {
 340         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 341         struct iovec iov = {
 342                 .iov_base = n,
 343                 .iov_len = n->nlmsg_len
 344         };
 345         struct msghdr msg = {
 346                 .msg_name = &nladdr,
 347                 .msg_namelen = sizeof(nladdr),
 348                 .msg_iov = &iov,
 349                 .msg_iovlen = 1,
 350         };
 351
 352         n->nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 353         n->nlmsg_pid = 0;
 354         n->nlmsg_seq = rth->dump = ++rth->seq;
 355
 356         return sendmsg(rth->fd, &msg, 0);
 357 }
 358
 359 static int rtnl_dump_done(struct nlmsghdr *h)
 360 {
 361         int len = *(int *)NLMSG_DATA(h);
 362
 363         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) {
 364                 fprintf(stderr, "DONE truncated\n");
 365                 return -1;
 366         }
 367
 368         if (len < 0) {
 369                 errno = -len;
 370                 switch (errno) {
 371                 case ENOENT:
 372                 case EOPNOTSUPP:
 373                         return -1;
 374                 case EMSGSIZE:
 375                         fprintf(stderr,
 376                                 "Error: Buffer too small for object.\n");
 377                         break;
 378                 default:
 379                         perror("RTNETLINK answers");
 380                 }
 381                 return len;
 382         }
 383
 384         /* check for any messages returned from kernel */
 385         nl_dump_ext_ack(h, NULL);
 386
 387         return 0;
 388 }
 389
 390 static void rtnl_dump_error(const struct rtnl_handle *rth,
 391                             struct nlmsghdr *h)
 392 {
 393
 394         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 395                 fprintf(stderr, "ERROR truncated\n");
 396         } else {
 397                 const struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 398
 399                 errno = -err->error;
 400                 if (rth->proto == NETLINK_SOCK_DIAG &&
 401                     (errno == ENOENT ||
 402                      errno == EOPNOTSUPP))
 403                         return;
 404
 405                 if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR))
 406                         perror("RTNETLINK answers");
 407         }
 408 }
 409
 410 static int __rtnl_recvmsg(int fd, struct msghdr *msg, int flags)
 411 {
 412         int len;
 413
 414         do {
 415                 len = recvmsg(fd, msg, flags);
 416         } while (len < 0 && (errno == EINTR || errno == EAGAIN));
 417
 418         if (len < 0) {
 419                 fprintf(stderr, "netlink receive error %s (%d)\n",
 420                         strerror(errno), errno);
 421                 return -errno;
 422         }
 423
 424         if (len == 0) {
 425                 fprintf(stderr, "EOF on netlink\n");
 426                 return -ENODATA;
 427         }
 428
 429         return len;
 430 }
 431
 432 static int rtnl_recvmsg(int fd, struct msghdr *msg, char **answer)
 433 {
 434         struct iovec *iov = msg->msg_iov;
 435         char *buf;
 436         int len;
 437
 438         iov->iov_base = NULL;
 439         iov->iov_len = 0;
 440
 441         len = __rtnl_recvmsg(fd, msg, MSG_PEEK | MSG_TRUNC);
 442         if (len < 0)
 443                 return len;
 444
 445         buf = malloc(len);
 446         if (!buf) {
 447                 fprintf(stderr, "malloc error: not enough buffer\n");
 448                 return -ENOMEM;
 449         }
 450
 451         iov->iov_base = buf;
 452         iov->iov_len = len;
 453
 454         len = __rtnl_recvmsg(fd, msg, 0);
 455         if (len < 0) {
 456                 free(buf);
 457                 return len;
 458         }
 459
 460         if (answer)
 461                 *answer = buf;
 462         else
 463                 free(buf);
 464
 465         return len;
 466 }
 467
 468 int rtnl_dump_filter_l(struct rtnl_handle *rth,
 469                        const struct rtnl_dump_filter_arg *arg)
 470 {
 471         struct sockaddr_nl nladdr;
 472         struct iovec iov;
 473         struct msghdr msg = {
 474                 .msg_name = &nladdr,
 475                 .msg_namelen = sizeof(nladdr),
 476                 .msg_iov = &iov,
 477                 .msg_iovlen = 1,
 478         };
 479         char *buf;
 480         int dump_intr = 0;
 481
 482         while (1) {
 483                 int status;
 484                 const struct rtnl_dump_filter_arg *a;
 485                 int found_done = 0;
 486                 int msglen = 0;
 487
 488                 status = rtnl_recvmsg(rth->fd, &msg, &buf);
 489                 if (status < 0)
 490                         return status;
 491
 492                 if (rth->dump_fp)
 493                         fwrite(buf, 1, NLMSG_ALIGN(status), rth->dump_fp);
 494
 495                 for (a = arg; a->filter; a++) {
 496                         struct nlmsghdr *h = (struct nlmsghdr *)buf;
 497
 498                         msglen = status;
 499
 500                         while (NLMSG_OK(h, msglen)) {
 501                                 int err = 0;
 502
 503                                 h->nlmsg_flags &= ~a->nc_flags;
 504
 505                                 if (nladdr.nl_pid != 0 ||
 506                                     h->nlmsg_pid != rth->local.nl_pid ||
 507                                     h->nlmsg_seq != rth->dump)
 508                                         goto skip_it;
 509
 510                                 if (h->nlmsg_flags & NLM_F_DUMP_INTR)
 511                                         dump_intr = 1;
 512
 513                                 if (h->nlmsg_type == NLMSG_DONE) {
 514                                         err = rtnl_dump_done(h);
 515                                         if (err < 0) {
 516                                                 free(buf);
 517                                                 return -1;
 518                                         }
 519
 520                                         found_done = 1;
 521                                         break; /* process next filter */
 522                                 }
 523
 524                                 if (h->nlmsg_type == NLMSG_ERROR) {
 525                                         rtnl_dump_error(rth, h);
 526                                         free(buf);
 527                                         return -1;
 528                                 }
 529
 530                                 if (!rth->dump_fp) {
 531                                         err = a->filter(&nladdr, h, a->arg1);
 532                                         if (err < 0) {
 533                                                 free(buf);
 534                                                 return err;
 535                                         }
 536                                 }
 537
 538 skip_it:
 539                                 h = NLMSG_NEXT(h, msglen);
 540                         }
 541                 }
 542                 free(buf);
 543
 544                 if (found_done) {
 545                         if (dump_intr)
 546                                 fprintf(stderr,
 547                                         "Dump was interrupted and may be inconsistent.\n");
 548                         return 0;
 549                 }
 550
 551                 if (msg.msg_flags & MSG_TRUNC) {
 552                         fprintf(stderr, "Message truncated\n");
 553                         continue;
 554                 }
 555                 if (msglen) {
 556                         fprintf(stderr, "!!!Remnant of size %d\n", msglen);
 557                         exit(1);
 558                 }
 559         }
 560 }
 561
 562 int rtnl_dump_filter_nc(struct rtnl_handle *rth,
 563                      rtnl_filter_t filter,
 564                      void *arg1, __u16 nc_flags)
 565 {
 566         const struct rtnl_dump_filter_arg a[2] = {
 567                 { .filter = filter, .arg1 = arg1, .nc_flags = nc_flags, },
 568                 { .filter = NULL,   .arg1 = NULL, .nc_flags = 0, },
 569         };
 570
 571         return rtnl_dump_filter_l(rth, a);
 572 }
 573
 574 static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err,
 575                             nl_ext_ack_fn_t errfn)
 576 {
 577         if (nl_dump_ext_ack(h, errfn))
 578                 return;
 579
 580         fprintf(stderr, "RTNETLINK answers: %s\n",
 581                 strerror(-err->error));
 582 }
 583
 584
 585 static int __rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iov,
 586                            size_t iovlen, struct nlmsghdr **answer,
 587                            bool show_rtnl_err, nl_ext_ack_fn_t errfn)
 588 {
 589         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 590         struct iovec riov;
 591         struct msghdr msg = {
 592                 .msg_name = &nladdr,
 593                 .msg_namelen = sizeof(nladdr),
 594                 .msg_iov = iov,
 595                 .msg_iovlen = iovlen,
 596         };
 597         unsigned int seq = 0;
 598         struct nlmsghdr *h;
 599         int i, status;
 600         char *buf;
 601
 602         for (i = 0; i < iovlen; i++) {
 603                 h = iov[i].iov_base;
 604                 h->nlmsg_seq = seq = ++rtnl->seq;
 605                 if (answer == NULL)
 606                         h->nlmsg_flags |= NLM_F_ACK;
 607         }
 608
 609         status = sendmsg(rtnl->fd, &msg, 0);
 610         if (status < 0) {
 611                 perror("Cannot talk to rtnetlink");
 612                 return -1;
 613         }
 614
 615         /* change msg to use the response iov */
 616         msg.msg_iov = &riov;
 617         msg.msg_iovlen = 1;
 618         i = 0;
 619         while (1) {
 620 next:
 621                 status = rtnl_recvmsg(rtnl->fd, &msg, &buf);
 622                 ++i;
 623
 624                 if (status < 0)
 625                         return status;
 626
 627                 if (msg.msg_namelen != sizeof(nladdr)) {
 628                         fprintf(stderr,
 629                                 "sender address length == %d\n",
 630                                 msg.msg_namelen);
 631                         exit(1);
 632                 }
 633                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
 634                         int len = h->nlmsg_len;
 635                         int l = len - sizeof(*h);
 636
 637                         if (l < 0 || len > status) {
 638                                 if (msg.msg_flags & MSG_TRUNC) {
 639                                         fprintf(stderr, "Truncated message\n");
 640                                         free(buf);
 641                                         return -1;
 642                                 }
 643                                 fprintf(stderr,
 644                                         "!!!malformed message: len=%d\n",
 645                                         len);
 646                                 exit(1);
 647                         }
 648
 649                         if (nladdr.nl_pid != 0 ||
 650                             h->nlmsg_pid != rtnl->local.nl_pid ||
 651                             h->nlmsg_seq > seq || h->nlmsg_seq < seq - iovlen) {
 652                                 /* Don't forget to skip that message. */
 653                                 status -= NLMSG_ALIGN(len);
 654                                 h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 655                                 continue;
 656                         }
 657
 658                         if (h->nlmsg_type == NLMSG_ERROR) {
 659                                 struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 660
 661                                 if (l < sizeof(struct nlmsgerr)) {
 662                                         fprintf(stderr, "ERROR truncated\n");
 663                                 } else if (!err->error) {
 664                                         /* check messages from kernel */
 665                                         nl_dump_ext_ack(h, errfn);
 666
 667                                         if (answer)
 668                                                 *answer = (struct nlmsghdr *)buf;
 669                                         else
 670                                                 free(buf);
 671                                         if (h->nlmsg_seq == seq)
 672                                                 return 0;
 673                                         else if (i < iovlen)
 674                                                 goto next;
 675                                         return 0;
 676                                 }
 677
 678                                 if (rtnl->proto != NETLINK_SOCK_DIAG &&
 679                                     show_rtnl_err)
 680                                         rtnl_talk_error(h, err, errfn);
 681
 682                                 errno = -err->error;
 683                                 free(buf);
 684                                 return -i;
 685                         }
 686
 687                         if (answer) {
 688                                 *answer = (struct nlmsghdr *)buf;
 689                                 return 0;
 690                         }
 691
 692                         fprintf(stderr, "Unexpected reply!!!\n");
 693
 694                         status -= NLMSG_ALIGN(len);
 695                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 696                 }
 697                 free(buf);
 698
 699                 if (msg.msg_flags & MSG_TRUNC) {
 700                         fprintf(stderr, "Message truncated\n");
 701                         continue;
 702                 }
 703
 704                 if (status) {
 705                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 706                         exit(1);
 707                 }
 708         }
 709 }
 710
 711 static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 712                        struct nlmsghdr **answer,
 713                        bool show_rtnl_err, nl_ext_ack_fn_t errfn)
 714 {
 715         struct iovec iov = {
 716                 .iov_base = n,
 717                 .iov_len = n->nlmsg_len
 718         };
 719
 720         return __rtnl_talk_iov(rtnl, &iov, 1, answer, show_rtnl_err, errfn);
 721 }
 722
 723 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 724               struct nlmsghdr **answer)
 725 {
 726         return __rtnl_talk(rtnl, n, answer, true, NULL);
 727 }
 728
 729 int rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iovec, size_t iovlen,
 730                   struct nlmsghdr **answer)
 731 {
 732         return __rtnl_talk_iov(rtnl, iovec, iovlen, answer, true, NULL);
 733 }
 734
 735 int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 736                      struct nlmsghdr **answer,
 737                      nl_ext_ack_fn_t errfn)
 738 {
 739         return __rtnl_talk(rtnl, n, answer, true, errfn);
 740 }
 741
 742 int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 743                                    struct nlmsghdr **answer)
 744 {
 745         return __rtnl_talk(rtnl, n, answer, false, NULL);
 746 }
 747
 748 int rtnl_listen_all_nsid(struct rtnl_handle *rth)
 749 {
 750         unsigned int on = 1;
 751
 752         if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, &on,
 753                        sizeof(on)) < 0) {
 754                 perror("NETLINK_LISTEN_ALL_NSID");
 755                 return -1;
 756         }
 757         rth->flags |= RTNL_HANDLE_F_LISTEN_ALL_NSID;
 758         return 0;
 759 }
 760
 761 int rtnl_listen(struct rtnl_handle *rtnl,
 762                 rtnl_listen_filter_t handler,
 763                 void *jarg)
 764 {
 765         int status;
 766         struct nlmsghdr *h;
 767         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 768         struct iovec iov;
 769         struct msghdr msg = {
 770                 .msg_name = &nladdr,
 771                 .msg_namelen = sizeof(nladdr),
 772                 .msg_iov = &iov,
 773                 .msg_iovlen = 1,
 774         };
 775         char   buf[16384];
 776         char   cmsgbuf[BUFSIZ];
 777
 778         if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 779                 msg.msg_control = &cmsgbuf;
 780                 msg.msg_controllen = sizeof(cmsgbuf);
 781         }
 782
 783         iov.iov_base = buf;
 784         while (1) {
 785                 struct rtnl_ctrl_data ctrl;
 786                 struct cmsghdr *cmsg;
 787
 788                 iov.iov_len = sizeof(buf);
 789                 status = recvmsg(rtnl->fd, &msg, 0);
 790
 791                 if (status < 0) {
 792                         if (errno == EINTR || errno == EAGAIN)
 793                                 continue;
 794                         fprintf(stderr, "netlink receive error %s (%d)\n",
 795                                 strerror(errno), errno);
 796                         if (errno == ENOBUFS)
 797                                 continue;
 798                         return -1;
 799                 }
 800                 if (status == 0) {
 801                         fprintf(stderr, "EOF on netlink\n");
 802                         return -1;
 803                 }
 804                 if (msg.msg_namelen != sizeof(nladdr)) {
 805                         fprintf(stderr,
 806                                 "Sender address length == %d\n",
 807                                 msg.msg_namelen);
 808                         exit(1);
 809                 }
 810
 811                 if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 812                         memset(&ctrl, 0, sizeof(ctrl));
 813                         ctrl.nsid = -1;
 814                         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg;
 815                              cmsg = CMSG_NXTHDR(&msg, cmsg))
 816                                 if (cmsg->cmsg_level == SOL_NETLINK &&
 817                                     cmsg->cmsg_type == NETLINK_LISTEN_ALL_NSID &&
 818                                     cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
 819                                         int *data = (int *)CMSG_DATA(cmsg);
 820
 821                                         ctrl.nsid = *data;
 822                                 }
 823                 }
 824
 825                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
 826                         int err;
 827                         int len = h->nlmsg_len;
 828                         int l = len - sizeof(*h);
 829
 830                         if (l < 0 || len > status) {
 831                                 if (msg.msg_flags & MSG_TRUNC) {
 832                                         fprintf(stderr, "Truncated message\n");
 833                                         return -1;
 834                                 }
 835                                 fprintf(stderr,
 836                                         "!!!malformed message: len=%d\n",
 837                                         len);
 838                                 exit(1);
 839                         }
 840
 841                         err = handler(&nladdr, &ctrl, h, jarg);
 842                         if (err < 0)
 843                                 return err;
 844
 845                         status -= NLMSG_ALIGN(len);
 846                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 847                 }
 848                 if (msg.msg_flags & MSG_TRUNC) {
 849                         fprintf(stderr, "Message truncated\n");
 850                         continue;
 851                 }
 852                 if (status) {
 853                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 854                         exit(1);
 855                 }
 856         }
 857 }
 858
 859 int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler,
 860                    void *jarg)
 861 {
 862         int status;
 863         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 864         char buf[16384];
 865         struct nlmsghdr *h = (struct nlmsghdr *)buf;
 866
 867         while (1) {
 868                 int err, len;
 869                 int l;
 870
 871                 status = fread(&buf, 1, sizeof(*h), rtnl);
 872
 873                 if (status < 0) {
 874                         if (errno == EINTR)
 875                                 continue;
 876                         perror("rtnl_from_file: fread");
 877                         return -1;
 878                 }
 879                 if (status == 0)
 880                         return 0;
 881
 882                 len = h->nlmsg_len;
 883                 l = len - sizeof(*h);
 884
 885                 if (l < 0 || len > sizeof(buf)) {
 886                         fprintf(stderr, "!!!malformed message: len=%d @%lu\n",
 887                                 len, ftell(rtnl));
 888                         return -1;
 889                 }
 890
 891                 status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
 892
 893                 if (status < 0) {
 894                         perror("rtnl_from_file: fread");
 895                         return -1;
 896                 }
 897                 if (status < l) {
 898                         fprintf(stderr, "rtnl-from_file: truncated message\n");
 899                         return -1;
 900                 }
 901
 902                 err = handler(&nladdr, NULL, h, jarg);
 903                 if (err < 0)
 904                         return err;
 905         }
 906 }
 907
 908 int addattr(struct nlmsghdr *n, int maxlen, int type)
 909 {
 910         return addattr_l(n, maxlen, type, NULL, 0);
 911 }
 912
 913 int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data)
 914 {
 915         return addattr_l(n, maxlen, type, &data, sizeof(__u8));
 916 }
 917
 918 int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data)
 919 {
 920         return addattr_l(n, maxlen, type, &data, sizeof(__u16));
 921 }
 922
 923 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
 924 {
 925         return addattr_l(n, maxlen, type, &data, sizeof(__u32));
 926 }
 927
 928 int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data)
 929 {
 930         return addattr_l(n, maxlen, type, &data, sizeof(__u64));
 931 }
 932
 933 int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str)
 934 {
 935         return addattr_l(n, maxlen, type, str, strlen(str)+1);
 936 }
 937
 938 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
 939               int alen)
 940 {
 941         int len = RTA_LENGTH(alen);
 942         struct rtattr *rta;
 943
 944         if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
 945                 fprintf(stderr,
 946                         "addattr_l ERROR: message exceeded bound of %d\n",
 947                         maxlen);
 948                 return -1;
 949         }
 950         rta = NLMSG_TAIL(n);
 951         rta->rta_type = type;
 952         rta->rta_len = len;
 953         if (alen)
 954                 memcpy(RTA_DATA(rta), data, alen);
 955         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
 956         return 0;
 957 }
 958
 959 int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
 960 {
 961         if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) {
 962                 fprintf(stderr,
 963                         "addraw_l ERROR: message exceeded bound of %d\n",
 964                         maxlen);
 965                 return -1;
 966         }
 967
 968         memcpy(NLMSG_TAIL(n), data, len);
 969         memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
 970         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
 971         return 0;
 972 }
 973
 974 struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
 975 {
 976         struct rtattr *nest = NLMSG_TAIL(n);
 977
 978         addattr_l(n, maxlen, type, NULL, 0);
 979         return nest;
 980 }
 981
 982 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
 983 {
 984         nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest;
 985         return n->nlmsg_len;
 986 }
 987
 988 struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
 989                                    const void *data, int len)
 990 {
 991         struct rtattr *start = NLMSG_TAIL(n);
 992
 993         addattr_l(n, maxlen, type, data, len);
 994         addattr_nest(n, maxlen, type);
 995         return start;
 996 }
 997
 998 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
 999 {
1000         struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len);
1001
1002         start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start;
1003         addattr_nest_end(n, nest);
1004         return n->nlmsg_len;
1005 }
1006
1007 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
1008 {
1009         int len = RTA_LENGTH(4);
1010         struct rtattr *subrta;
1011
1012         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
1013                 fprintf(stderr,
1014                         "rta_addattr32: Error! max allowed bound %d exceeded\n",
1015                         maxlen);
1016                 return -1;
1017         }
1018         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
1019         subrta->rta_type = type;
1020         subrta->rta_len = len;
1021         memcpy(RTA_DATA(subrta), &data, 4);
1022         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
1023         return 0;
1024 }
1025
1026 int rta_addattr_l(struct rtattr *rta, int maxlen, int type,
1027                   const void *data, int alen)
1028 {
1029         struct rtattr *subrta;
1030         int len = RTA_LENGTH(alen);
1031
1032         if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen) {
1033                 fprintf(stderr,
1034                         "rta_addattr_l: Error! max allowed bound %d exceeded\n",
1035                         maxlen);
1036                 return -1;
1037         }
1038         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
1039         subrta->rta_type = type;
1040         subrta->rta_len = len;
1041         if (alen)
1042                 memcpy(RTA_DATA(subrta), data, alen);
1043         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
1044         return 0;
1045 }
1046
1047 int rta_addattr8(struct rtattr *rta, int maxlen, int type, __u8 data)
1048 {
1049         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u8));
1050 }
1051
1052 int rta_addattr16(struct rtattr *rta, int maxlen, int type, __u16 data)
1053 {
1054         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u16));
1055 }
1056
1057 int rta_addattr64(struct rtattr *rta, int maxlen, int type, __u64 data)
1058 {
1059         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u64));
1060 }
1061
1062 struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type)
1063 {
1064         struct rtattr *nest = RTA_TAIL(rta);
1065
1066         rta_addattr_l(rta, maxlen, type, NULL, 0);
1067
1068         return nest;
1069 }
1070
1071 int rta_nest_end(struct rtattr *rta, struct rtattr *nest)
1072 {
1073         nest->rta_len = (void *)RTA_TAIL(rta) - (void *)nest;
1074
1075         return rta->rta_len;
1076 }
1077
1078 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
1079 {
1080         return parse_rtattr_flags(tb, max, rta, len, 0);
1081 }
1082
1083 int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
1084                        int len, unsigned short flags)
1085 {
1086         unsigned short type;
1087
1088         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1089         while (RTA_OK(rta, len)) {
1090                 type = rta->rta_type & ~flags;
1091                 if ((type <= max) && (!tb[type]))
1092                         tb[type] = rta;
1093                 rta = RTA_NEXT(rta, len);
1094         }
1095         if (len)
1096                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1097                         len, rta->rta_len);
1098         return 0;
1099 }
1100
1101 int parse_rtattr_byindex(struct rtattr *tb[], int max,
1102                          struct rtattr *rta, int len)
1103 {
1104         int i = 0;
1105
1106         memset(tb, 0, sizeof(struct rtattr *) * max);
1107         while (RTA_OK(rta, len)) {
1108                 if (rta->rta_type <= max && i < max)
1109                         tb[i++] = rta;
1110                 rta = RTA_NEXT(rta, len);
1111         }
1112         if (len)
1113                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1114                         len, rta->rta_len);
1115         return i;
1116 }
1117
1118 struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len)
1119 {
1120         while (RTA_OK(rta, len)) {
1121                 if (rta->rta_type == type)
1122                         return rta;
1123                 rta = RTA_NEXT(rta, len);
1124         }
1125
1126         if (len)
1127                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1128                         len, rta->rta_len);
1129         return NULL;
1130 }
1131
1132 int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
1133                                  struct rtattr *rta,
1134                                  int len)
1135 {
1136         if (RTA_PAYLOAD(rta) < len)
1137                 return -1;
1138         if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
1139                 rta = RTA_DATA(rta) + RTA_ALIGN(len);
1140                 return parse_rtattr_nested(tb, max, rta);
1141         }
1142         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1143         return 0;
1144 }