networking/libiproute/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 <sys/socket.h>
  14
  15 #include <errno.h>
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <time.h>
  19 #include <unistd.h>
  20
  21 #include <sys/uio.h>
  22
  23 #include "libnetlink.h"
  24 #include "libbb.h"
  25
  26 void rtnl_close(struct rtnl_handle *rth)
  27 {
  28         close(rth->fd);
  29 }
  30
  31 int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
  32 {
  33         int addr_len;
  34
  35         memset(rth, 0, sizeof(rth));
  36
  37         rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  38         if (rth->fd < 0) {
  39                 bb_perror_msg("Cannot open netlink socket");
  40                 return -1;
  41         }
  42
  43         memset(&rth->local, 0, sizeof(rth->local));
  44         rth->local.nl_family = AF_NETLINK;
  45         rth->local.nl_groups = subscriptions;
  46
  47         if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) {
  48                 bb_perror_msg("Cannot bind netlink socket");
  49                 return -1;
  50         }
  51         addr_len = sizeof(rth->local);
  52         if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {
  53                 bb_perror_msg("Cannot getsockname");
  54                 return -1;
  55         }
  56         if (addr_len != sizeof(rth->local)) {
  57                 bb_error_msg("Wrong address length %d", addr_len);
  58                 return -1;
  59         }
  60         if (rth->local.nl_family != AF_NETLINK) {
  61                 bb_error_msg("Wrong address family %d", rth->local.nl_family);
  62                 return -1;
  63         }
  64         rth->seq = time(NULL);
  65         return 0;
  66 }
  67
  68 int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
  69 {
  70         struct {
  71                 struct nlmsghdr nlh;
  72                 struct rtgenmsg g;
  73         } req;
  74         struct sockaddr_nl nladdr;
  75
  76         memset(&nladdr, 0, sizeof(nladdr));
  77         nladdr.nl_family = AF_NETLINK;
  78
  79         req.nlh.nlmsg_len = sizeof(req);
  80         req.nlh.nlmsg_type = type;
  81         req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
  82         req.nlh.nlmsg_pid = 0;
  83         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
  84         req.g.rtgen_family = family;
  85
  86         return sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr));
  87 }
  88
  89 int rtnl_send(struct rtnl_handle *rth, char *buf, int len)
  90 {
  91         struct sockaddr_nl nladdr;
  92
  93         memset(&nladdr, 0, sizeof(nladdr));
  94         nladdr.nl_family = AF_NETLINK;
  95
  96         return sendto(rth->fd, buf, len, 0, (struct sockaddr*)&nladdr, sizeof(nladdr));
  97 }
  98
  99 int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
 100 {
 101         struct nlmsghdr nlh;
 102         struct sockaddr_nl nladdr;
 103         struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } };
 104         struct msghdr msg = {
 105                 (void*)&nladdr, sizeof(nladdr),
 106                 iov,    2,
 107                 NULL,   0,
 108                 0
 109         };
 110
 111         memset(&nladdr, 0, sizeof(nladdr));
 112         nladdr.nl_family = AF_NETLINK;
 113
 114         nlh.nlmsg_len = NLMSG_LENGTH(len);
 115         nlh.nlmsg_type = type;
 116         nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
 117         nlh.nlmsg_pid = 0;
 118         nlh.nlmsg_seq = rth->dump = ++rth->seq;
 119
 120         return sendmsg(rth->fd, &msg, 0);
 121 }
 122
 123 int rtnl_dump_filter(struct rtnl_handle *rth,
 124                      int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
 125                      void *arg1,
 126                      int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 127                      void *arg2)
 128 {
 129         char    buf[8192];
 130         struct sockaddr_nl nladdr;
 131         struct iovec iov = { buf, sizeof(buf) };
 132
 133         while (1) {
 134                 int status;
 135                 struct nlmsghdr *h;
 136
 137                 struct msghdr msg = {
 138                         (void*)&nladdr, sizeof(nladdr),
 139                         &iov,   1,
 140                         NULL,   0,
 141                         0
 142                 };
 143
 144                 status = recvmsg(rth->fd, &msg, 0);
 145
 146                 if (status < 0) {
 147                         if (errno == EINTR)
 148                                 continue;
 149                         bb_perror_msg("OVERRUN");
 150                         continue;
 151                 }
 152                 if (status == 0) {
 153                         bb_error_msg("EOF on netlink");
 154                         return -1;
 155                 }
 156                 if (msg.msg_namelen != sizeof(nladdr)) {
 157                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 158                 }
 159
 160                 h = (struct nlmsghdr*)buf;
 161                 while (NLMSG_OK(h, status)) {
 162                         int err;
 163
 164                         if (h->nlmsg_pid != rth->local.nl_pid ||
 165                             h->nlmsg_seq != rth->dump) {
 166                                 if (junk) {
 167                                         err = junk(&nladdr, h, arg2);
 168                                         if (err < 0) {
 169                                                 return err;
 170                                         }
 171                                 }
 172                                 goto skip_it;
 173                         }
 174
 175                         if (h->nlmsg_type == NLMSG_DONE) {
 176                                 return 0;
 177                         }
 178                         if (h->nlmsg_type == NLMSG_ERROR) {
 179                                 struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
 180                                 if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 181                                         bb_error_msg("ERROR truncated");
 182                                 } else {
 183                                         errno = -l_err->error;
 184                                         bb_perror_msg("RTNETLINK answers");
 185                                 }
 186                                 return -1;
 187                         }
 188                         err = filter(&nladdr, h, arg1);
 189                         if (err < 0) {
 190                                 return err;
 191                         }
 192
 193 skip_it:
 194                         h = NLMSG_NEXT(h, status);
 195                 }
 196                 if (msg.msg_flags & MSG_TRUNC) {
 197                         bb_error_msg("Message truncated");
 198                         continue;
 199                 }
 200                 if (status) {
 201                         bb_error_msg_and_die("!!!Remnant of size %d", status);
 202                 }
 203         }
 204 }
 205
 206 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
 207               unsigned groups, struct nlmsghdr *answer,
 208               int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 209               void *jarg)
 210 {
 211         int status;
 212         unsigned seq;
 213         struct nlmsghdr *h;
 214         struct sockaddr_nl nladdr;
 215         struct iovec iov = { (void*)n, n->nlmsg_len };
 216         char   buf[8192];
 217         struct msghdr msg = {
 218                 (void*)&nladdr, sizeof(nladdr),
 219                 &iov,   1,
 220                 NULL,   0,
 221                 0
 222         };
 223
 224         memset(&nladdr, 0, sizeof(nladdr));
 225         nladdr.nl_family = AF_NETLINK;
 226         nladdr.nl_pid = peer;
 227         nladdr.nl_groups = groups;
 228
 229         n->nlmsg_seq = seq = ++rtnl->seq;
 230         if (answer == NULL) {
 231                 n->nlmsg_flags |= NLM_F_ACK;
 232         }
 233         status = sendmsg(rtnl->fd, &msg, 0);
 234
 235         if (status < 0) {
 236                 bb_perror_msg("Cannot talk to rtnetlink");
 237                 return -1;
 238         }
 239
 240         iov.iov_base = buf;
 241
 242         while (1) {
 243                 iov.iov_len = sizeof(buf);
 244                 status = recvmsg(rtnl->fd, &msg, 0);
 245
 246                 if (status < 0) {
 247                         if (errno == EINTR) {
 248                                 continue;
 249                         }
 250                         bb_perror_msg("OVERRUN");
 251                         continue;
 252                 }
 253                 if (status == 0) {
 254                         bb_error_msg("EOF on netlink");
 255                         return -1;
 256                 }
 257                 if (msg.msg_namelen != sizeof(nladdr)) {
 258                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 259                 }
 260                 for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
 261                         int l_err;
 262                         int len = h->nlmsg_len;
 263                         int l = len - sizeof(*h);
 264
 265                         if (l<0 || len>status) {
 266                                 if (msg.msg_flags & MSG_TRUNC) {
 267                                         bb_error_msg("Truncated message");
 268                                         return -1;
 269                                 }
 270                                 bb_error_msg_and_die("!!!malformed message: len=%d", len);
 271                         }
 272
 273                         if (h->nlmsg_pid != rtnl->local.nl_pid ||
 274                             h->nlmsg_seq != seq) {
 275                                 if (junk) {
 276                                         l_err = junk(&nladdr, h, jarg);
 277                                         if (l_err < 0) {
 278                                                 return l_err;
 279                                         }
 280                                 }
 281                                 continue;
 282                         }
 283
 284                         if (h->nlmsg_type == NLMSG_ERROR) {
 285                                 struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 286                                 if (l < sizeof(struct nlmsgerr)) {
 287                                         bb_error_msg("ERROR truncated");
 288                                 } else {
 289                                         errno = -err->error;
 290                                         if (errno == 0) {
 291                                                 if (answer) {
 292                                                         memcpy(answer, h, h->nlmsg_len);
 293                                                 }
 294                                                 return 0;
 295                                         }
 296                                         bb_perror_msg("RTNETLINK answers");
 297                                 }
 298                                 return -1;
 299                         }
 300                         if (answer) {
 301                                 memcpy(answer, h, h->nlmsg_len);
 302                                 return 0;
 303                         }
 304
 305                         bb_error_msg("Unexpected reply!!!");
 306
 307                         status -= NLMSG_ALIGN(len);
 308                         h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 309                 }
 310                 if (msg.msg_flags & MSG_TRUNC) {
 311                         bb_error_msg("Message truncated");
 312                         continue;
 313                 }
 314                 if (status) {
 315                         bb_error_msg_and_die("!!!Remnant of size %d", status);
 316                 }
 317         }
 318 }
 319
 320 int rtnl_listen(struct rtnl_handle *rtnl,
 321               int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 322               void *jarg)
 323 {
 324         int status;
 325         struct nlmsghdr *h;
 326         struct sockaddr_nl nladdr;
 327         struct iovec iov;
 328         char   buf[8192];
 329         struct msghdr msg = {
 330                 (void*)&nladdr, sizeof(nladdr),
 331                 &iov,   1,
 332                 NULL,   0,
 333                 0
 334         };
 335
 336         memset(&nladdr, 0, sizeof(nladdr));
 337         nladdr.nl_family = AF_NETLINK;
 338         nladdr.nl_pid = 0;
 339         nladdr.nl_groups = 0;
 340
 341
 342         iov.iov_base = buf;
 343
 344         while (1) {
 345                 iov.iov_len = sizeof(buf);
 346                 status = recvmsg(rtnl->fd, &msg, 0);
 347
 348                 if (status < 0) {
 349                         if (errno == EINTR)
 350                                 continue;
 351                         bb_perror_msg("OVERRUN");
 352                         continue;
 353                 }
 354                 if (status == 0) {
 355                         bb_error_msg("EOF on netlink");
 356                         return -1;
 357                 }
 358                 if (msg.msg_namelen != sizeof(nladdr)) {
 359                         bb_error_msg_and_die("Sender address length == %d", msg.msg_namelen);
 360                 }
 361                 for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
 362                         int err;
 363                         int len = h->nlmsg_len;
 364                         int l = len - sizeof(*h);
 365
 366                         if (l<0 || len>status) {
 367                                 if (msg.msg_flags & MSG_TRUNC) {
 368                                         bb_error_msg("Truncated message");
 369                                         return -1;
 370                                 }
 371                                 bb_error_msg_and_die("!!!malformed message: len=%d", len);
 372                         }
 373
 374                         err = handler(&nladdr, h, jarg);
 375                         if (err < 0) {
 376                                 return err;
 377                         }
 378
 379                         status -= NLMSG_ALIGN(len);
 380                         h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 381                 }
 382                 if (msg.msg_flags & MSG_TRUNC) {
 383                         bb_error_msg("Message truncated");
 384                         continue;
 385                 }
 386                 if (status) {
 387                         bb_error_msg_and_die("!!!Remnant of size %d", status);
 388                 }
 389         }
 390 }
 391
 392 int rtnl_from_file(FILE *rtnl,
 393               int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
 394               void *jarg)
 395 {
 396         int status;
 397         struct sockaddr_nl nladdr;
 398         char   buf[8192];
 399         struct nlmsghdr *h = (void*)buf;
 400
 401         memset(&nladdr, 0, sizeof(nladdr));
 402         nladdr.nl_family = AF_NETLINK;
 403         nladdr.nl_pid = 0;
 404         nladdr.nl_groups = 0;
 405
 406         while (1) {
 407                 int err, len, type;
 408                 int l;
 409
 410                 status = fread(&buf, 1, sizeof(*h), rtnl);
 411
 412                 if (status < 0) {
 413                         if (errno == EINTR)
 414                                 continue;
 415                         bb_perror_msg("rtnl_from_file: fread");
 416                         return -1;
 417                 }
 418                 if (status == 0)
 419                         return 0;
 420
 421                 len = h->nlmsg_len;
 422                 type= h->nlmsg_type;
 423                 l = len - sizeof(*h);
 424
 425                 if (l<0 || len>sizeof(buf)) {
 426                         bb_error_msg("!!!malformed message: len=%d @%lu",
 427                                 len, ftell(rtnl));
 428                         return -1;
 429                 }
 430
 431                 status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);
 432
 433                 if (status < 0) {
 434                         bb_perror_msg("rtnl_from_file: fread");
 435                         return -1;
 436                 }
 437                 if (status < l) {
 438                         bb_error_msg("rtnl-from_file: truncated message");
 439                         return -1;
 440                 }
 441
 442                 err = handler(&nladdr, h, jarg);
 443                 if (err < 0)
 444                         return err;
 445         }
 446 }
 447
 448 int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data)
 449 {
 450         int len = RTA_LENGTH(4);
 451         struct rtattr *rta;
 452         if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
 453                 return -1;
 454         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 455         rta->rta_type = type;
 456         rta->rta_len = len;
 457         memcpy(RTA_DATA(rta), &data, 4);
 458         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 459         return 0;
 460 }
 461
 462 int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
 463 {
 464         int len = RTA_LENGTH(alen);
 465         struct rtattr *rta;
 466
 467         if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
 468                 return -1;
 469         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 470         rta->rta_type = type;
 471         rta->rta_len = len;
 472         memcpy(RTA_DATA(rta), data, alen);
 473         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 474         return 0;
 475 }
 476
 477 int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)
 478 {
 479         int len = RTA_LENGTH(4);
 480         struct rtattr *subrta;
 481
 482         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 483                 return -1;
 484         }
 485         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 486         subrta->rta_type = type;
 487         subrta->rta_len = len;
 488         memcpy(RTA_DATA(subrta), &data, 4);
 489         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 490         return 0;
 491 }
 492
 493 int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
 494 {
 495         struct rtattr *subrta;
 496         int len = RTA_LENGTH(alen);
 497
 498         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 499                 return -1;
 500         }
 501         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 502         subrta->rta_type = type;
 503         subrta->rta_len = len;
 504         memcpy(RTA_DATA(subrta), data, alen);
 505         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 506         return 0;
 507 }
 508
 509
 510 int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 511 {
 512         while (RTA_OK(rta, len)) {
 513                 if (rta->rta_type <= max) {
 514                         tb[rta->rta_type] = rta;
 515                 }
 516                 rta = RTA_NEXT(rta,len);
 517         }
 518         if (len) {
 519                 bb_error_msg("!!!Deficit %d, rta_len=%d", len, rta->rta_len);
 520         }
 521         return 0;
 522 }