networking/libiproute/libnetlink.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU General Public License
   5  * as published by the Free Software Foundation; either version
   6  * 2 of the License, or (at your option) any later version.
   7  *
   8  * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   9  */
  10
  11 #include <sys/socket.h>
  12 #include <sys/uio.h>
  13
  14 #include "libbb.h"
  15 #include "libnetlink.h"
  16
  17 void FAST_FUNC xrtnl_open(struct rtnl_handle *rth/*, unsigned subscriptions*/)
  18 {
  19         socklen_t addr_len;
  20
  21         memset(rth, 0, sizeof(*rth));
  22         rth->fd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
  23         rth->local.nl_family = AF_NETLINK;
  24         /*rth->local.nl_groups = subscriptions;*/
  25
  26         xbind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local));
  27         addr_len = sizeof(rth->local);
  28         getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len);
  29
  30 /* too much paranoia
  31         if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0)
  32                 bb_perror_msg_and_die("getsockname");
  33         if (addr_len != sizeof(rth->local))
  34                 bb_error_msg_and_die("wrong address length %d", addr_len);
  35         if (rth->local.nl_family != AF_NETLINK)
  36                 bb_error_msg_and_die("wrong address family %d", rth->local.nl_family);
  37 */
  38         rth->seq = time(NULL);
  39 }
  40
  41 int FAST_FUNC xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
  42 {
  43         struct {
  44                 struct nlmsghdr nlh;
  45                 struct rtgenmsg g;
  46         } req;
  47
  48         req.nlh.nlmsg_len = sizeof(req);
  49         req.nlh.nlmsg_type = type;
  50         req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
  51         req.nlh.nlmsg_pid = 0;
  52         req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
  53         req.g.rtgen_family = family;
  54
  55         return rtnl_send(rth, (void*)&req, sizeof(req));
  56 }
  57
  58 //TODO: pass rth->fd instead of full rth?
  59 int FAST_FUNC rtnl_send(struct rtnl_handle *rth, char *buf, int len)
  60 {
  61         struct sockaddr_nl nladdr;
  62
  63         memset(&nladdr, 0, sizeof(nladdr));
  64         nladdr.nl_family = AF_NETLINK;
  65
  66         return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr));
  67 }
  68
  69 int FAST_FUNC rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
  70 {
  71         struct nlmsghdr nlh;
  72         struct sockaddr_nl nladdr;
  73         struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } };
  74         /* Use designated initializers, struct layout is non-portable */
  75         struct msghdr msg = {
  76                 .msg_name = (void*)&nladdr,
  77                 .msg_namelen = sizeof(nladdr),
  78                 .msg_iov = iov,
  79                 .msg_iovlen = 2,
  80                 .msg_control = NULL,
  81                 .msg_controllen = 0,
  82                 .msg_flags = 0
  83         };
  84
  85         memset(&nladdr, 0, sizeof(nladdr));
  86         nladdr.nl_family = AF_NETLINK;
  87
  88         nlh.nlmsg_len = NLMSG_LENGTH(len);
  89         nlh.nlmsg_type = type;
  90         nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
  91         nlh.nlmsg_pid = 0;
  92         nlh.nlmsg_seq = rth->dump = ++rth->seq;
  93
  94         return sendmsg(rth->fd, &msg, 0);
  95 }
  96
  97 static int rtnl_dump_filter(struct rtnl_handle *rth,
  98                 int (*filter)(const struct sockaddr_nl *, struct nlmsghdr *n, void *) FAST_FUNC,
  99                 void *arg1/*,
 100                 int (*junk)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
 101                 void *arg2*/)
 102 {
 103         int retval = -1;
 104         char *buf = xmalloc(8*1024); /* avoid big stack buffer */
 105         struct sockaddr_nl nladdr;
 106         struct iovec iov = { buf, 8*1024 };
 107
 108         while (1) {
 109                 int status;
 110                 struct nlmsghdr *h;
 111                 /* Use designated initializers, struct layout is non-portable */
 112                 struct msghdr msg = {
 113                         .msg_name = (void*)&nladdr,
 114                         .msg_namelen = sizeof(nladdr),
 115                         .msg_iov = &iov,
 116                         .msg_iovlen = 1,
 117                         .msg_control = NULL,
 118                         .msg_controllen = 0,
 119                         .msg_flags = 0
 120                 };
 121
 122                 status = recvmsg(rth->fd, &msg, 0);
 123
 124                 if (status < 0) {
 125                         if (errno == EINTR)
 126                                 continue;
 127                         bb_perror_msg("OVERRUN");
 128                         continue;
 129                 }
 130                 if (status == 0) {
 131                         bb_error_msg("EOF on netlink");
 132                         goto ret;
 133                 }
 134                 if (msg.msg_namelen != sizeof(nladdr)) {
 135                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 136                 }
 137
 138                 h = (struct nlmsghdr*)buf;
 139                 while (NLMSG_OK(h, status)) {
 140                         int err;
 141
 142                         if (nladdr.nl_pid != 0 ||
 143                             h->nlmsg_pid != rth->local.nl_pid ||
 144                             h->nlmsg_seq != rth->dump
 145                         ) {
 146 //                              if (junk) {
 147 //                                      err = junk(&nladdr, h, arg2);
 148 //                                      if (err < 0) {
 149 //                                              retval = err;
 150 //                                              goto ret;
 151 //                                      }
 152 //                              }
 153                                 goto skip_it;
 154                         }
 155
 156                         if (h->nlmsg_type == NLMSG_DONE) {
 157                                 goto ret_0;
 158                         }
 159                         if (h->nlmsg_type == NLMSG_ERROR) {
 160                                 struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
 161                                 if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 162                                         bb_error_msg("ERROR truncated");
 163                                 } else {
 164                                         errno = -l_err->error;
 165                                         bb_perror_msg("RTNETLINK answers");
 166                                 }
 167                                 goto ret;
 168                         }
 169                         err = filter(&nladdr, h, arg1);
 170                         if (err < 0) {
 171                                 retval = err;
 172                                 goto ret;
 173                         }
 174
 175  skip_it:
 176                         h = NLMSG_NEXT(h, status);
 177                 }
 178                 if (msg.msg_flags & MSG_TRUNC) {
 179                         bb_error_msg("message truncated");
 180                         continue;
 181                 }
 182                 if (status) {
 183                         bb_error_msg_and_die("remnant of size %d!", status);
 184                 }
 185         } /* while (1) */
 186  ret_0:
 187         retval++; /* = 0 */
 188  ret:
 189         free(buf);
 190         return retval;
 191 }
 192
 193 int FAST_FUNC xrtnl_dump_filter(struct rtnl_handle *rth,
 194                 int (*filter)(const struct sockaddr_nl *, struct nlmsghdr *, void *) FAST_FUNC,
 195                 void *arg1)
 196 {
 197         int ret = rtnl_dump_filter(rth, filter, arg1/*, NULL, NULL*/);
 198         if (ret < 0)
 199                 bb_error_msg_and_die("dump terminated");
 200         return ret;
 201 }
 202
 203 int FAST_FUNC rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 204                 pid_t peer, unsigned groups,
 205                 struct nlmsghdr *answer,
 206                 int (*junk)(struct sockaddr_nl *, struct nlmsghdr *, void *),
 207                 void *jarg)
 208 {
 209 /* bbox doesn't use parameters no. 3, 4, 6, 7, they are stubbed out */
 210 #define peer   0
 211 #define groups 0
 212 #define junk   NULL
 213 #define jarg   NULL
 214         int retval = -1;
 215         int status;
 216         unsigned seq;
 217         struct nlmsghdr *h;
 218         struct sockaddr_nl nladdr;
 219         struct iovec iov = { (void*)n, n->nlmsg_len };
 220         char   *buf = xmalloc(8*1024); /* avoid big stack buffer */
 221         /* Use designated initializers, struct layout is non-portable */
 222         struct msghdr msg = {
 223                 .msg_name = (void*)&nladdr,
 224                 .msg_namelen = sizeof(nladdr),
 225                 .msg_iov = &iov,
 226                 .msg_iovlen = 1,
 227                 .msg_control = NULL,
 228                 .msg_controllen = 0,
 229                 .msg_flags = 0
 230         };
 231
 232         memset(&nladdr, 0, sizeof(nladdr));
 233         nladdr.nl_family = AF_NETLINK;
 234 //      nladdr.nl_pid = peer;
 235 //      nladdr.nl_groups = groups;
 236
 237         n->nlmsg_seq = seq = ++rtnl->seq;
 238         if (answer == NULL) {
 239                 n->nlmsg_flags |= NLM_F_ACK;
 240         }
 241         status = sendmsg(rtnl->fd, &msg, 0);
 242
 243         if (status < 0) {
 244                 bb_perror_msg("can't talk to rtnetlink");
 245                 goto ret;
 246         }
 247
 248         iov.iov_base = buf;
 249
 250         while (1) {
 251                 iov.iov_len = 8*1024;
 252                 status = recvmsg(rtnl->fd, &msg, 0);
 253
 254                 if (status < 0) {
 255                         if (errno == EINTR) {
 256                                 continue;
 257                         }
 258                         bb_perror_msg("OVERRUN");
 259                         continue;
 260                 }
 261                 if (status == 0) {
 262                         bb_error_msg("EOF on netlink");
 263                         goto ret;
 264                 }
 265                 if (msg.msg_namelen != sizeof(nladdr)) {
 266                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 267                 }
 268                 for (h = (struct nlmsghdr*)buf; status >= (int)sizeof(*h); ) {
 269 //                      int l_err;
 270                         int len = h->nlmsg_len;
 271                         int l = len - sizeof(*h);
 272
 273                         if (l < 0 || len > status) {
 274                                 if (msg.msg_flags & MSG_TRUNC) {
 275                                         bb_error_msg("truncated message");
 276                                         goto ret;
 277                                 }
 278                                 bb_error_msg_and_die("malformed message: len=%d!", len);
 279                         }
 280
 281                         if (nladdr.nl_pid != peer ||
 282                             h->nlmsg_pid != rtnl->local.nl_pid ||
 283                             h->nlmsg_seq != seq
 284                         ) {
 285 //                              if (junk) {
 286 //                                      l_err = junk(&nladdr, h, jarg);
 287 //                                      if (l_err < 0) {
 288 //                                              retval = l_err;
 289 //                                              goto ret;
 290 //                                      }
 291 //                              }
 292                                 continue;
 293                         }
 294
 295                         if (h->nlmsg_type == NLMSG_ERROR) {
 296                                 struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
 297                                 if (l < (int)sizeof(struct nlmsgerr)) {
 298                                         bb_error_msg("ERROR truncated");
 299                                 } else {
 300                                         errno = - err->error;
 301                                         if (errno == 0) {
 302                                                 if (answer) {
 303                                                         memcpy(answer, h, h->nlmsg_len);
 304                                                 }
 305                                                 goto ret_0;
 306                                         }
 307                                         bb_perror_msg("RTNETLINK answers");
 308                                 }
 309                                 goto ret;
 310                         }
 311                         if (answer) {
 312                                 memcpy(answer, h, h->nlmsg_len);
 313                                 goto ret_0;
 314                         }
 315
 316                         bb_error_msg("unexpected reply!");
 317
 318                         status -= NLMSG_ALIGN(len);
 319                         h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
 320                 }
 321                 if (msg.msg_flags & MSG_TRUNC) {
 322                         bb_error_msg("message truncated");
 323                         continue;
 324                 }
 325                 if (status) {
 326                         bb_error_msg_and_die("remnant of size %d!", status);
 327                 }
 328         } /* while (1) */
 329  ret_0:
 330         retval++; /* = 0 */
 331  ret:
 332         free(buf);
 333         return retval;
 334 }
 335
 336 int FAST_FUNC addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data)
 337 {
 338         int len = RTA_LENGTH(4);
 339         struct rtattr *rta;
 340
 341         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
 342                 return -1;
 343         }
 344         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 345         rta->rta_type = type;
 346         rta->rta_len = len;
 347         move_to_unaligned32(RTA_DATA(rta), data);
 348         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 349         return 0;
 350 }
 351
 352 int FAST_FUNC addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
 353 {
 354         int len = RTA_LENGTH(alen);
 355         struct rtattr *rta;
 356
 357         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
 358                 return -1;
 359         }
 360         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 361         rta->rta_type = type;
 362         rta->rta_len = len;
 363         memcpy(RTA_DATA(rta), data, alen);
 364         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 365         return 0;
 366 }
 367
 368 int FAST_FUNC rta_addattr32(struct rtattr *rta, int maxlen, int type, uint32_t data)
 369 {
 370         int len = RTA_LENGTH(4);
 371         struct rtattr *subrta;
 372
 373         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 374                 return -1;
 375         }
 376         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 377         subrta->rta_type = type;
 378         subrta->rta_len = len;
 379         move_to_unaligned32(RTA_DATA(subrta), data);
 380         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 381         return 0;
 382 }
 383
 384 int FAST_FUNC rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
 385 {
 386         struct rtattr *subrta;
 387         int len = RTA_LENGTH(alen);
 388
 389         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 390                 return -1;
 391         }
 392         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 393         subrta->rta_type = type;
 394         subrta->rta_len = len;
 395         memcpy(RTA_DATA(subrta), data, alen);
 396         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 397         return 0;
 398 }
 399
 400
 401 void FAST_FUNC parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 402 {
 403         while (RTA_OK(rta, len)) {
 404                 if (rta->rta_type <= max) {
 405                         tb[rta->rta_type] = rta;
 406                 }
 407                 rta = RTA_NEXT(rta, len);
 408         }
 409         if (len) {
 410                 bb_error_msg("deficit %d, rta_len=%d!", len, rta->rta_len);
 411         }
 412 }