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 <syslog.h>
  18 #include <fcntl.h>
  19 #include <net/if_arp.h>
  20 #include <sys/socket.h>
  21 #include <netinet/in.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <time.h>
  25 #include <sys/uio.h>
  26
  27 #include "libnetlink.h"
  28
  29 #ifndef SOL_NETLINK
  30 #define SOL_NETLINK 270
  31 #endif
  32
  33 #ifndef MIN
  34 #define MIN(a, b) ((a) < (b) ? (a) : (b))
  35 #endif
  36
  37 int rcvbuf = 1024 * 1024;
  38
  39 #ifdef HAVE_LIBMNL
  40 #include <libmnl/libmnl.h>
  41
  42 static const enum mnl_attr_data_type extack_policy[NLMSGERR_ATTR_MAX + 1] = {
  43         [NLMSGERR_ATTR_MSG]     = MNL_TYPE_NUL_STRING,
  44         [NLMSGERR_ATTR_OFFS]    = MNL_TYPE_U32,
  45 };
  46
  47 static int err_attr_cb(const struct nlattr *attr, void *data)
  48 {
  49         const struct nlattr **tb = data;
  50         uint16_t type;
  51
  52         if (mnl_attr_type_valid(attr, NLMSGERR_ATTR_MAX) < 0)
  53                 return MNL_CB_ERROR;
  54
  55         type = mnl_attr_get_type(attr);
  56         if (mnl_attr_validate(attr, extack_policy[type]) < 0)
  57                 return MNL_CB_ERROR;
  58
  59
  60         tb[type] = attr;
  61         return MNL_CB_OK;
  62 }
  63
  64 /* dump netlink extended ack error message */
  65 static int nl_dump_ext_err(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
  66 {
  67         struct nlattr *tb[NLMSGERR_ATTR_MAX + 1];
  68         const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
  69         const struct nlmsghdr *err_nlh = NULL;
  70         unsigned int hlen = sizeof(*err);
  71         const char *errmsg = NULL;
  72         uint32_t off = 0;
  73
  74         /* no TLVs, nothing to do here */
  75         if (!(nlh->nlmsg_flags & NLM_F_ACK_TLVS))
  76                 return 0;
  77
  78         /* if NLM_F_CAPPED is set then the inner err msg was capped */
  79         if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
  80                 hlen += mnl_nlmsg_get_payload_len(&err->msg);
  81
  82         mnl_attr_parse(nlh, hlen, err_attr_cb, tb);
  83
  84         if (tb[NLMSGERR_ATTR_MSG])
  85                 errmsg = mnl_attr_get_str(tb[NLMSGERR_ATTR_MSG]);
  86
  87         if (tb[NLMSGERR_ATTR_OFFS]) {
  88                 off = mnl_attr_get_u32(tb[NLMSGERR_ATTR_OFFS]);
  89
  90                 if (off > nlh->nlmsg_len) {
  91                         fprintf(stderr,
  92                                 "Invalid offset for NLMSGERR_ATTR_OFFS\n");
  93                         off = 0;
  94                 } else if (!(nlh->nlmsg_flags & NLM_F_CAPPED))
  95                         err_nlh = &err->msg;
  96         }
  97
  98         if (errfn)
  99                 return errfn(errmsg, off, err_nlh);
 100
 101         if (errmsg && *errmsg != '\0') {
 102                 fprintf(stderr, "Error: %s", errmsg);
 103                 if (errmsg[strlen(errmsg) - 1] != '.')
 104                         fprintf(stderr, ".");
 105                 fprintf(stderr, "\n");
 106
 107                 return 1;
 108         }
 109
 110         return 0;
 111 }
 112 #else
 113 #warning "libmnl required for error support"
 114
 115 /* No extended error ack without libmnl */
 116 static int nl_dump_ext_err(const struct nlmsghdr *nlh, nl_ext_ack_fn_t errfn)
 117 {
 118         return 0;
 119 }
 120 #endif
 121
 122 void rtnl_close(struct rtnl_handle *rth)
 123 {
 124         if (rth->fd >= 0) {
 125                 close(rth->fd);
 126                 rth->fd = -1;
 127         }
 128 }
 129
 130 int rtnl_open_byproto(struct rtnl_handle *rth, unsigned int subscriptions,
 131                       int protocol)
 132 {
 133         socklen_t addr_len;
 134         int sndbuf = 32768;
 135         int one = 1;
 136
 137         memset(rth, 0, sizeof(*rth));
 138
 139         rth->proto = protocol;
 140         rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
 141         if (rth->fd < 0) {
 142                 perror("Cannot open netlink socket");
 143                 return -1;
 144         }
 145
 146         if (setsockopt(rth->fd, SOL_SOCKET, SO_SNDBUF,
 147                        &sndbuf, sizeof(sndbuf)) < 0) {
 148                 perror("SO_SNDBUF");
 149                 return -1;
 150         }
 151
 152         if (setsockopt(rth->fd, SOL_SOCKET, SO_RCVBUF,
 153                        &rcvbuf, sizeof(rcvbuf)) < 0) {
 154                 perror("SO_RCVBUF");
 155                 return -1;
 156         }
 157
 158         /* Older kernels may no support extended ACK reporting */
 159         setsockopt(rth->fd, SOL_NETLINK, NETLINK_EXT_ACK,
 160                    &one, sizeof(one));
 161
 162         memset(&rth->local, 0, sizeof(rth->local));
 163         rth->local.nl_family = AF_NETLINK;
 164         rth->local.nl_groups = subscriptions;
 165
 166         if (bind(rth->fd, (struct sockaddr *)&rth->local,
 167                  sizeof(rth->local)) < 0) {
 168                 perror("Cannot bind netlink socket");
 169                 return -1;
 170         }
 171         addr_len = sizeof(rth->local);
 172         if (getsockname(rth->fd, (struct sockaddr *)&rth->local,
 173                         &addr_len) < 0) {
 174                 perror("Cannot getsockname");
 175                 return -1;
 176         }
 177         if (addr_len != sizeof(rth->local)) {
 178                 fprintf(stderr, "Wrong address length %d\n", addr_len);
 179                 return -1;
 180         }
 181         if (rth->local.nl_family != AF_NETLINK) {
 182                 fprintf(stderr, "Wrong address family %d\n",
 183                         rth->local.nl_family);
 184                 return -1;
 185         }
 186         rth->seq = time(NULL);
 187         return 0;
 188 }
 189
 190 int rtnl_open(struct rtnl_handle *rth, unsigned int subscriptions)
 191 {
 192         return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);
 193 }
 194
 195 int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
 196 {
 197         return rtnl_wilddump_req_filter(rth, family, type, RTEXT_FILTER_VF);
 198 }
 199
 200 int rtnl_wilddump_req_filter(struct rtnl_handle *rth, int family, int type,
 201                             __u32 filt_mask)
 202 {
 203         struct {
 204                 struct nlmsghdr nlh;
 205                 struct ifinfomsg ifm;
 206                 /* attribute has to be NLMSG aligned */
 207                 struct rtattr ext_req __attribute__ ((aligned(NLMSG_ALIGNTO)));
 208                 __u32 ext_filter_mask;
 209         } req = {
 210                 .nlh.nlmsg_len = sizeof(req),
 211                 .nlh.nlmsg_type = type,
 212                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 213                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 214                 .ifm.ifi_family = family,
 215                 .ext_req.rta_type = IFLA_EXT_MASK,
 216                 .ext_req.rta_len = RTA_LENGTH(sizeof(__u32)),
 217                 .ext_filter_mask = filt_mask,
 218         };
 219
 220         return send(rth->fd, &req, sizeof(req), 0);
 221 }
 222
 223 int rtnl_wilddump_req_filter_fn(struct rtnl_handle *rth, int family, int type,
 224                                 req_filter_fn_t filter_fn)
 225 {
 226         struct {
 227                 struct nlmsghdr nlh;
 228                 struct ifinfomsg ifm;
 229                 char buf[1024];
 230         } req = {
 231                 .nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
 232                 .nlh.nlmsg_type = type,
 233                 .nlh.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 234                 .nlh.nlmsg_seq = rth->dump = ++rth->seq,
 235                 .ifm.ifi_family = family,
 236         };
 237         int err;
 238
 239         if (!filter_fn)
 240                 return -EINVAL;
 241
 242         err = filter_fn(&req.nlh, sizeof(req));
 243         if (err)
 244                 return err;
 245
 246         return send(rth->fd, &req, req.nlh.nlmsg_len, 0);
 247 }
 248
 249 int rtnl_wilddump_stats_req_filter(struct rtnl_handle *rth, int fam, int type,
 250                                    __u32 filt_mask)
 251 {
 252         struct {
 253                 struct nlmsghdr nlh;
 254                 struct if_stats_msg ifsm;
 255         } req;
 256
 257         memset(&req, 0, sizeof(req));
 258         req.nlh.nlmsg_len = NLMSG_LENGTH(sizeof(struct if_stats_msg));
 259         req.nlh.nlmsg_type = type;
 260         req.nlh.nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 261         req.nlh.nlmsg_pid = 0;
 262         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
 263         req.ifsm.family = fam;
 264         req.ifsm.filter_mask = filt_mask;
 265
 266         return send(rth->fd, &req, sizeof(req), 0);
 267 }
 268
 269 int rtnl_send(struct rtnl_handle *rth, const void *buf, int len)
 270 {
 271         return send(rth->fd, buf, len, 0);
 272 }
 273
 274 int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int len)
 275 {
 276         struct nlmsghdr *h;
 277         int status;
 278         char resp[1024];
 279
 280         status = send(rth->fd, buf, len, 0);
 281         if (status < 0)
 282                 return status;
 283
 284         /* Check for immediate errors */
 285         status = recv(rth->fd, resp, sizeof(resp), MSG_DONTWAIT|MSG_PEEK);
 286         if (status < 0) {
 287                 if (errno == EAGAIN)
 288                         return 0;
 289                 return -1;
 290         }
 291
 292         for (h = (struct nlmsghdr *)resp; NLMSG_OK(h, status);
 293              h = NLMSG_NEXT(h, status)) {
 294                 if (h->nlmsg_type == NLMSG_ERROR) {
 295                         struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 296
 297                         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
 298                                 fprintf(stderr, "ERROR truncated\n");
 299                         else
 300                                 errno = -err->error;
 301                         return -1;
 302                 }
 303         }
 304
 305         return 0;
 306 }
 307
 308 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 309 {
 310         struct nlmsghdr nlh = {
 311                 .nlmsg_len = NLMSG_LENGTH(len),
 312                 .nlmsg_type = type,
 313                 .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
 314                 .nlmsg_seq = rth->dump = ++rth->seq,
 315         };
 316         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 317         struct iovec iov[2] = {
 318                 { .iov_base = &nlh, .iov_len = sizeof(nlh) },
 319                 { .iov_base = req, .iov_len = len }
 320         };
 321         struct msghdr msg = {
 322                 .msg_name = &nladdr,
 323                 .msg_namelen = sizeof(nladdr),
 324                 .msg_iov = iov,
 325                 .msg_iovlen = 2,
 326         };
 327
 328         return sendmsg(rth->fd, &msg, 0);
 329 }
 330
 331 int rtnl_dump_request_n(struct rtnl_handle *rth, struct nlmsghdr *n)
 332 {
 333         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 334         struct iovec iov = {
 335                 .iov_base = n,
 336                 .iov_len = n->nlmsg_len
 337         };
 338         struct msghdr msg = {
 339                 .msg_name = &nladdr,
 340                 .msg_namelen = sizeof(nladdr),
 341                 .msg_iov = &iov,
 342                 .msg_iovlen = 1,
 343         };
 344
 345         n->nlmsg_flags = NLM_F_DUMP|NLM_F_REQUEST;
 346         n->nlmsg_pid = 0;
 347         n->nlmsg_seq = rth->dump = ++rth->seq;
 348
 349         return sendmsg(rth->fd, &msg, 0);
 350 }
 351
 352 static int rtnl_dump_done(const struct rtnl_handle *rth,
 353                           struct nlmsghdr *h)
 354 {
 355         int len = *(int *)NLMSG_DATA(h);
 356
 357         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(int))) {
 358                 fprintf(stderr, "DONE truncated\n");
 359                 return -1;
 360         }
 361
 362         if (len < 0) {
 363                 errno = -len;
 364                 switch (errno) {
 365                 case ENOENT:
 366                 case EOPNOTSUPP:
 367                         return -1;
 368                 case EMSGSIZE:
 369                         fprintf(stderr,
 370                                 "Error: Buffer too small for object.\n");
 371                         break;
 372                 default:
 373                         perror("RTNETLINK answers");
 374                 }
 375                 return len;
 376         }
 377
 378         return 0;
 379 }
 380
 381 static void rtnl_dump_error(const struct rtnl_handle *rth,
 382                             struct nlmsghdr *h)
 383 {
 384
 385         if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 386                 fprintf(stderr, "ERROR truncated\n");
 387         } else {
 388                 const struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 389
 390                 errno = -err->error;
 391                 if (rth->proto == NETLINK_SOCK_DIAG &&
 392                     (errno == ENOENT ||
 393                      errno == EOPNOTSUPP))
 394                         return;
 395
 396                 if (!(rth->flags & RTNL_HANDLE_F_SUPPRESS_NLERR))
 397                         perror("RTNETLINK answers");
 398         }
 399 }
 400
 401 int rtnl_dump_filter_l(struct rtnl_handle *rth,
 402                        const struct rtnl_dump_filter_arg *arg)
 403 {
 404         struct sockaddr_nl nladdr;
 405         struct iovec iov;
 406         struct msghdr msg = {
 407                 .msg_name = &nladdr,
 408                 .msg_namelen = sizeof(nladdr),
 409                 .msg_iov = &iov,
 410                 .msg_iovlen = 1,
 411         };
 412         char buf[32768];
 413         int dump_intr = 0;
 414
 415         iov.iov_base = buf;
 416         while (1) {
 417                 int status;
 418                 const struct rtnl_dump_filter_arg *a;
 419                 int found_done = 0;
 420                 int msglen = 0;
 421
 422                 iov.iov_len = sizeof(buf);
 423                 status = recvmsg(rth->fd, &msg, 0);
 424
 425                 if (status < 0) {
 426                         if (errno == EINTR || errno == EAGAIN)
 427                                 continue;
 428                         fprintf(stderr, "netlink receive error %s (%d)\n",
 429                                 strerror(errno), errno);
 430                         return -1;
 431                 }
 432
 433                 if (status == 0) {
 434                         fprintf(stderr, "EOF on netlink\n");
 435                         return -1;
 436                 }
 437
 438                 if (rth->dump_fp)
 439                         fwrite(buf, 1, NLMSG_ALIGN(status), rth->dump_fp);
 440
 441                 for (a = arg; a->filter; a++) {
 442                         struct nlmsghdr *h = (struct nlmsghdr *)buf;
 443
 444                         msglen = status;
 445
 446                         while (NLMSG_OK(h, msglen)) {
 447                                 int err = 0;
 448
 449                                 h->nlmsg_flags &= ~a->nc_flags;
 450
 451                                 if (nladdr.nl_pid != 0 ||
 452                                     h->nlmsg_pid != rth->local.nl_pid ||
 453                                     h->nlmsg_seq != rth->dump)
 454                                         goto skip_it;
 455
 456                                 if (h->nlmsg_flags & NLM_F_DUMP_INTR)
 457                                         dump_intr = 1;
 458
 459                                 if (h->nlmsg_type == NLMSG_DONE) {
 460                                         err = rtnl_dump_done(rth, h);
 461                                         if (err < 0)
 462                                                 return -1;
 463
 464                                         found_done = 1;
 465                                         break; /* process next filter */
 466                                 }
 467
 468                                 if (h->nlmsg_type == NLMSG_ERROR) {
 469                                         rtnl_dump_error(rth, h);
 470                                         return -1;
 471                                 }
 472
 473                                 if (!rth->dump_fp) {
 474                                         err = a->filter(&nladdr, h, a->arg1);
 475                                         if (err < 0)
 476                                                 return err;
 477                                 }
 478
 479 skip_it:
 480                                 h = NLMSG_NEXT(h, msglen);
 481                         }
 482                 }
 483
 484                 if (found_done) {
 485                         if (dump_intr)
 486                                 fprintf(stderr,
 487                                         "Dump was interrupted and may be inconsistent.\n");
 488                         return 0;
 489                 }
 490
 491                 if (msg.msg_flags & MSG_TRUNC) {
 492                         fprintf(stderr, "Message truncated\n");
 493                         continue;
 494                 }
 495                 if (msglen) {
 496                         fprintf(stderr, "!!!Remnant of size %d\n", msglen);
 497                         exit(1);
 498                 }
 499         }
 500 }
 501
 502 int rtnl_dump_filter_nc(struct rtnl_handle *rth,
 503                      rtnl_filter_t filter,
 504                      void *arg1, __u16 nc_flags)
 505 {
 506         const struct rtnl_dump_filter_arg a[2] = {
 507                 { .filter = filter, .arg1 = arg1, .nc_flags = nc_flags, },
 508                 { .filter = NULL,   .arg1 = NULL, .nc_flags = 0, },
 509         };
 510
 511         return rtnl_dump_filter_l(rth, a);
 512 }
 513
 514 static void rtnl_talk_error(struct nlmsghdr *h, struct nlmsgerr *err,
 515                             nl_ext_ack_fn_t errfn)
 516 {
 517         if (nl_dump_ext_err(h, errfn))
 518                 return;
 519
 520         fprintf(stderr, "RTNETLINK answers: %s\n",
 521                 strerror(-err->error));
 522 }
 523
 524 static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 525                        struct nlmsghdr *answer, size_t maxlen,
 526                        bool show_rtnl_err, nl_ext_ack_fn_t errfn)
 527 {
 528         int status;
 529         unsigned int seq;
 530         struct nlmsghdr *h;
 531         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 532         struct iovec iov = {
 533                 .iov_base = n,
 534                 .iov_len = n->nlmsg_len
 535         };
 536         struct msghdr msg = {
 537                 .msg_name = &nladdr,
 538                 .msg_namelen = sizeof(nladdr),
 539                 .msg_iov = &iov,
 540                 .msg_iovlen = 1,
 541         };
 542         char   buf[32768] = {};
 543
 544         n->nlmsg_seq = seq = ++rtnl->seq;
 545
 546         if (answer == NULL)
 547                 n->nlmsg_flags |= NLM_F_ACK;
 548
 549         status = sendmsg(rtnl->fd, &msg, 0);
 550         if (status < 0) {
 551                 perror("Cannot talk to rtnetlink");
 552                 return -1;
 553         }
 554
 555         iov.iov_base = buf;
 556         while (1) {
 557                 iov.iov_len = sizeof(buf);
 558                 status = recvmsg(rtnl->fd, &msg, 0);
 559
 560                 if (status < 0) {
 561                         if (errno == EINTR || errno == EAGAIN)
 562                                 continue;
 563                         fprintf(stderr, "netlink receive error %s (%d)\n",
 564                                 strerror(errno), errno);
 565                         return -1;
 566                 }
 567                 if (status == 0) {
 568                         fprintf(stderr, "EOF on netlink\n");
 569                         return -1;
 570                 }
 571                 if (msg.msg_namelen != sizeof(nladdr)) {
 572                         fprintf(stderr,
 573                                 "sender address length == %d\n",
 574                                 msg.msg_namelen);
 575                         exit(1);
 576                 }
 577                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
 578                         int len = h->nlmsg_len;
 579                         int l = len - sizeof(*h);
 580
 581                         if (l < 0 || len > status) {
 582                                 if (msg.msg_flags & MSG_TRUNC) {
 583                                         fprintf(stderr, "Truncated message\n");
 584                                         return -1;
 585                                 }
 586                                 fprintf(stderr,
 587                                         "!!!malformed message: len=%d\n",
 588                                         len);
 589                                 exit(1);
 590                         }
 591
 592                         if (nladdr.nl_pid != 0 ||
 593                             h->nlmsg_pid != rtnl->local.nl_pid ||
 594                             h->nlmsg_seq != seq) {
 595                                 /* Don't forget to skip that message. */
 596                                 status -= NLMSG_ALIGN(len);
 597                                 h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 598                                 continue;
 599                         }
 600
 601                         if (h->nlmsg_type == NLMSG_ERROR) {
 602                                 struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(h);
 603
 604                                 if (l < sizeof(struct nlmsgerr)) {
 605                                         fprintf(stderr, "ERROR truncated\n");
 606                                 } else if (!err->error) {
 607                                         if (answer)
 608                                                 memcpy(answer, h,
 609                                                        MIN(maxlen, h->nlmsg_len));
 610                                         return 0;
 611                                 }
 612
 613                                 if (rtnl->proto != NETLINK_SOCK_DIAG &&
 614                                     show_rtnl_err)
 615                                         rtnl_talk_error(h, err, errfn);
 616
 617                                 errno = -err->error;
 618                                 return -1;
 619                         }
 620
 621                         if (answer) {
 622                                 memcpy(answer, h,
 623                                        MIN(maxlen, h->nlmsg_len));
 624                                 return 0;
 625                         }
 626
 627                         fprintf(stderr, "Unexpected reply!!!\n");
 628
 629                         status -= NLMSG_ALIGN(len);
 630                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 631                 }
 632
 633                 if (msg.msg_flags & MSG_TRUNC) {
 634                         fprintf(stderr, "Message truncated\n");
 635                         continue;
 636                 }
 637
 638                 if (status) {
 639                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 640                         exit(1);
 641                 }
 642         }
 643 }
 644
 645 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 646               struct nlmsghdr *answer, size_t maxlen)
 647 {
 648         return __rtnl_talk(rtnl, n, answer, maxlen, true, NULL);
 649 }
 650
 651 int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 652                      struct nlmsghdr *answer, size_t maxlen,
 653                      nl_ext_ack_fn_t errfn)
 654 {
 655         return __rtnl_talk(rtnl, n, answer, maxlen, true, errfn);
 656 }
 657
 658 int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 659                                    struct nlmsghdr *answer, size_t maxlen)
 660 {
 661         return __rtnl_talk(rtnl, n, answer, maxlen, false, NULL);
 662 }
 663
 664 int rtnl_listen_all_nsid(struct rtnl_handle *rth)
 665 {
 666         unsigned int on = 1;
 667
 668         if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, &on,
 669                        sizeof(on)) < 0) {
 670                 perror("NETLINK_LISTEN_ALL_NSID");
 671                 return -1;
 672         }
 673         rth->flags |= RTNL_HANDLE_F_LISTEN_ALL_NSID;
 674         return 0;
 675 }
 676
 677 int rtnl_listen(struct rtnl_handle *rtnl,
 678                 rtnl_listen_filter_t handler,
 679                 void *jarg)
 680 {
 681         int status;
 682         struct nlmsghdr *h;
 683         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 684         struct iovec iov;
 685         struct msghdr msg = {
 686                 .msg_name = &nladdr,
 687                 .msg_namelen = sizeof(nladdr),
 688                 .msg_iov = &iov,
 689                 .msg_iovlen = 1,
 690         };
 691         char   buf[16384];
 692         char   cmsgbuf[BUFSIZ];
 693
 694         if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 695                 msg.msg_control = &cmsgbuf;
 696                 msg.msg_controllen = sizeof(cmsgbuf);
 697         }
 698
 699         iov.iov_base = buf;
 700         while (1) {
 701                 struct rtnl_ctrl_data ctrl;
 702                 struct cmsghdr *cmsg;
 703
 704                 iov.iov_len = sizeof(buf);
 705                 status = recvmsg(rtnl->fd, &msg, 0);
 706
 707                 if (status < 0) {
 708                         if (errno == EINTR || errno == EAGAIN)
 709                                 continue;
 710                         fprintf(stderr, "netlink receive error %s (%d)\n",
 711                                 strerror(errno), errno);
 712                         if (errno == ENOBUFS)
 713                                 continue;
 714                         return -1;
 715                 }
 716                 if (status == 0) {
 717                         fprintf(stderr, "EOF on netlink\n");
 718                         return -1;
 719                 }
 720                 if (msg.msg_namelen != sizeof(nladdr)) {
 721                         fprintf(stderr,
 722                                 "Sender address length == %d\n",
 723                                 msg.msg_namelen);
 724                         exit(1);
 725                 }
 726
 727                 if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
 728                         memset(&ctrl, 0, sizeof(ctrl));
 729                         ctrl.nsid = -1;
 730                         for (cmsg = CMSG_FIRSTHDR(&msg); cmsg;
 731                              cmsg = CMSG_NXTHDR(&msg, cmsg))
 732                                 if (cmsg->cmsg_level == SOL_NETLINK &&
 733                                     cmsg->cmsg_type == NETLINK_LISTEN_ALL_NSID &&
 734                                     cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
 735                                         int *data = (int *)CMSG_DATA(cmsg);
 736
 737                                         ctrl.nsid = *data;
 738                                 }
 739                 }
 740
 741                 for (h = (struct nlmsghdr *)buf; status >= sizeof(*h); ) {
 742                         int err;
 743                         int len = h->nlmsg_len;
 744                         int l = len - sizeof(*h);
 745
 746                         if (l < 0 || len > status) {
 747                                 if (msg.msg_flags & MSG_TRUNC) {
 748                                         fprintf(stderr, "Truncated message\n");
 749                                         return -1;
 750                                 }
 751                                 fprintf(stderr,
 752                                         "!!!malformed message: len=%d\n",
 753                                         len);
 754                                 exit(1);
 755                         }
 756
 757                         err = handler(&nladdr, &ctrl, h, jarg);
 758                         if (err < 0)
 759                                 return err;
 760
 761                         status -= NLMSG_ALIGN(len);
 762                         h = (struct nlmsghdr *)((char *)h + NLMSG_ALIGN(len));
 763                 }
 764                 if (msg.msg_flags & MSG_TRUNC) {
 765                         fprintf(stderr, "Message truncated\n");
 766                         continue;
 767                 }
 768                 if (status) {
 769                         fprintf(stderr, "!!!Remnant of size %d\n", status);
 770                         exit(1);
 771                 }
 772         }
 773 }
 774
 775 int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler,
 776                    void *jarg)
 777 {
 778         int status;
 779         struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
 780         char buf[16384];
 781         struct nlmsghdr *h = (struct nlmsghdr *)buf;
 782
 783         while (1) {
 784                 int err, len;
 785                 int l;
 786
 787                 status = fread(&buf, 1, sizeof(*h), rtnl);
 788
 789                 if (status < 0) {
 790                         if (errno == EINTR)
 791                                 continue;
 792                         perror("rtnl_from_file: fread");
 793                         return -1;
 794                 }
 795                 if (status == 0)
 796                         return 0;
 797
 798                 len = h->nlmsg_len;
 799                 l = len - sizeof(*h);
 800
 801                 if (l < 0 || len > sizeof(buf)) {
 802                         fprintf(stderr, "!!!malformed message: len=%d @%lu\n",
 803                                 len, ftell(rtnl));
 804                         return -1;
 805                 }
 806
 807                 status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
 808
 809                 if (status < 0) {
 810                         perror("rtnl_from_file: fread");
 811                         return -1;
 812                 }
 813                 if (status < l) {
 814                         fprintf(stderr, "rtnl-from_file: truncated message\n");
 815                         return -1;
 816                 }
 817
 818                 err = handler(&nladdr, NULL, h, jarg);
 819                 if (err < 0)
 820                         return err;
 821         }
 822 }
 823
 824 int addattr(struct nlmsghdr *n, int maxlen, int type)
 825 {
 826         return addattr_l(n, maxlen, type, NULL, 0);
 827 }
 828
 829 int addattr8(struct nlmsghdr *n, int maxlen, int type, __u8 data)
 830 {
 831         return addattr_l(n, maxlen, type, &data, sizeof(__u8));
 832 }
 833
 834 int addattr16(struct nlmsghdr *n, int maxlen, int type, __u16 data)
 835 {
 836         return addattr_l(n, maxlen, type, &data, sizeof(__u16));
 837 }
 838
 839 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
 840 {
 841         return addattr_l(n, maxlen, type, &data, sizeof(__u32));
 842 }
 843
 844 int addattr64(struct nlmsghdr *n, int maxlen, int type, __u64 data)
 845 {
 846         return addattr_l(n, maxlen, type, &data, sizeof(__u64));
 847 }
 848
 849 int addattrstrz(struct nlmsghdr *n, int maxlen, int type, const char *str)
 850 {
 851         return addattr_l(n, maxlen, type, str, strlen(str)+1);
 852 }
 853
 854 int addattr_l(struct nlmsghdr *n, int maxlen, int type, const void *data,
 855               int alen)
 856 {
 857         int len = RTA_LENGTH(alen);
 858         struct rtattr *rta;
 859
 860         if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
 861                 fprintf(stderr,
 862                         "addattr_l ERROR: message exceeded bound of %d\n",
 863                         maxlen);
 864                 return -1;
 865         }
 866         rta = NLMSG_TAIL(n);
 867         rta->rta_type = type;
 868         rta->rta_len = len;
 869         memcpy(RTA_DATA(rta), data, alen);
 870         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
 871         return 0;
 872 }
 873
 874 int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
 875 {
 876         if (NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len) > maxlen) {
 877                 fprintf(stderr,
 878                         "addraw_l ERROR: message exceeded bound of %d\n",
 879                         maxlen);
 880                 return -1;
 881         }
 882
 883         memcpy(NLMSG_TAIL(n), data, len);
 884         memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
 885         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
 886         return 0;
 887 }
 888
 889 struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
 890 {
 891         struct rtattr *nest = NLMSG_TAIL(n);
 892
 893         addattr_l(n, maxlen, type, NULL, 0);
 894         return nest;
 895 }
 896
 897 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
 898 {
 899         nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest;
 900         return n->nlmsg_len;
 901 }
 902
 903 struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
 904                                    const void *data, int len)
 905 {
 906         struct rtattr *start = NLMSG_TAIL(n);
 907
 908         addattr_l(n, maxlen, type, data, len);
 909         addattr_nest(n, maxlen, type);
 910         return start;
 911 }
 912
 913 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
 914 {
 915         struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len);
 916
 917         start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start;
 918         addattr_nest_end(n, nest);
 919         return n->nlmsg_len;
 920 }
 921
 922 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
 923 {
 924         int len = RTA_LENGTH(4);
 925         struct rtattr *subrta;
 926
 927         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 928                 fprintf(stderr,
 929                         "rta_addattr32: Error! max allowed bound %d exceeded\n",
 930                         maxlen);
 931                 return -1;
 932         }
 933         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
 934         subrta->rta_type = type;
 935         subrta->rta_len = len;
 936         memcpy(RTA_DATA(subrta), &data, 4);
 937         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 938         return 0;
 939 }
 940
 941 int rta_addattr_l(struct rtattr *rta, int maxlen, int type,
 942                   const void *data, int alen)
 943 {
 944         struct rtattr *subrta;
 945         int len = RTA_LENGTH(alen);
 946
 947         if (RTA_ALIGN(rta->rta_len) + RTA_ALIGN(len) > maxlen) {
 948                 fprintf(stderr,
 949                         "rta_addattr_l: Error! max allowed bound %d exceeded\n",
 950                         maxlen);
 951                 return -1;
 952         }
 953         subrta = (struct rtattr *)(((char *)rta) + RTA_ALIGN(rta->rta_len));
 954         subrta->rta_type = type;
 955         subrta->rta_len = len;
 956         memcpy(RTA_DATA(subrta), data, alen);
 957         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + RTA_ALIGN(len);
 958         return 0;
 959 }
 960
 961 int rta_addattr8(struct rtattr *rta, int maxlen, int type, __u8 data)
 962 {
 963         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u8));
 964 }
 965
 966 int rta_addattr16(struct rtattr *rta, int maxlen, int type, __u16 data)
 967 {
 968         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u16));
 969 }
 970
 971 int rta_addattr64(struct rtattr *rta, int maxlen, int type, __u64 data)
 972 {
 973         return rta_addattr_l(rta, maxlen, type, &data, sizeof(__u64));
 974 }
 975
 976 struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type)
 977 {
 978         struct rtattr *nest = RTA_TAIL(rta);
 979
 980         rta_addattr_l(rta, maxlen, type, NULL, 0);
 981
 982         return nest;
 983 }
 984
 985 int rta_nest_end(struct rtattr *rta, struct rtattr *nest)
 986 {
 987         nest->rta_len = (void *)RTA_TAIL(rta) - (void *)nest;
 988
 989         return rta->rta_len;
 990 }
 991
 992 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 993 {
 994         return parse_rtattr_flags(tb, max, rta, len, 0);
 995 }
 996
 997 int parse_rtattr_flags(struct rtattr *tb[], int max, struct rtattr *rta,
 998                        int len, unsigned short flags)
 999 {
1000         unsigned short type;
1001
1002         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1003         while (RTA_OK(rta, len)) {
1004                 type = rta->rta_type & ~flags;
1005                 if ((type <= max) && (!tb[type]))
1006                         tb[type] = rta;
1007                 rta = RTA_NEXT(rta, len);
1008         }
1009         if (len)
1010                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1011                         len, rta->rta_len);
1012         return 0;
1013 }
1014
1015 int parse_rtattr_byindex(struct rtattr *tb[], int max,
1016                          struct rtattr *rta, int len)
1017 {
1018         int i = 0;
1019
1020         memset(tb, 0, sizeof(struct rtattr *) * max);
1021         while (RTA_OK(rta, len)) {
1022                 if (rta->rta_type <= max && i < max)
1023                         tb[i++] = rta;
1024                 rta = RTA_NEXT(rta, len);
1025         }
1026         if (len)
1027                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1028                         len, rta->rta_len);
1029         return i;
1030 }
1031
1032 struct rtattr *parse_rtattr_one(int type, struct rtattr *rta, int len)
1033 {
1034         while (RTA_OK(rta, len)) {
1035                 if (rta->rta_type == type)
1036                         return rta;
1037                 rta = RTA_NEXT(rta, len);
1038         }
1039
1040         if (len)
1041                 fprintf(stderr, "!!!Deficit %d, rta_len=%d\n",
1042                         len, rta->rta_len);
1043         return NULL;
1044 }
1045
1046 int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
1047                                  struct rtattr *rta,
1048                                  int len)
1049 {
1050         if (RTA_PAYLOAD(rta) < len)
1051                 return -1;
1052         if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
1053                 rta = RTA_DATA(rta) + RTA_ALIGN(len);
1054                 return parse_rtattr_nested(tb, max, rta);
1055         }
1056         memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
1057         return 0;
1058 }