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         struct msghdr msg = {
  75                 (void*)&nladdr, sizeof(nladdr),
  76                 iov,  2,
  77                 NULL, 0,
  78                 0
  79         };
  80
  81         memset(&nladdr, 0, sizeof(nladdr));
  82         nladdr.nl_family = AF_NETLINK;
  83
  84         nlh.nlmsg_len = NLMSG_LENGTH(len);
  85         nlh.nlmsg_type = type;
  86         nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
  87         nlh.nlmsg_pid = 0;
  88         nlh.nlmsg_seq = rth->dump = ++rth->seq;
  89
  90         return sendmsg(rth->fd, &msg, 0);
  91 }
  92
  93 static int rtnl_dump_filter(struct rtnl_handle *rth,
  94                 int (*filter)(const struct sockaddr_nl *, struct nlmsghdr *n, void *) FAST_FUNC,
  95                 void *arg1/*,
  96                 int (*junk)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
  97                 void *arg2*/)
  98 {
  99         int retval = -1;
 100         char *buf = xmalloc(8*1024); /* avoid big stack buffer */
 101         struct sockaddr_nl nladdr;
 102         struct iovec iov = { buf, 8*1024 };
 103
 104         while (1) {
 105                 int status;
 106                 struct nlmsghdr *h;
 107
 108                 struct msghdr msg = {
 109                         (void*)&nladdr, sizeof(nladdr),
 110                         &iov, 1,
 111                         NULL, 0,
 112                         0
 113                 };
 114
 115                 status = recvmsg(rth->fd, &msg, 0);
 116
 117                 if (status < 0) {
 118                         if (errno == EINTR)
 119                                 continue;
 120                         bb_perror_msg("OVERRUN");
 121                         continue;
 122                 }
 123                 if (status == 0) {
 124                         bb_error_msg("EOF on netlink");
 125                         goto ret;
 126                 }
 127                 if (msg.msg_namelen != sizeof(nladdr)) {
 128                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 129                 }
 130
 131                 h = (struct nlmsghdr*)buf;
 132                 while (NLMSG_OK(h, status)) {
 133                         int err;
 134
 135                         if (nladdr.nl_pid != 0 ||
 136                             h->nlmsg_pid != rth->local.nl_pid ||
 137                             h->nlmsg_seq != rth->dump
 138                         ) {
 139 //                              if (junk) {
 140 //                                      err = junk(&nladdr, h, arg2);
 141 //                                      if (err < 0) {
 142 //                                              retval = err;
 143 //                                              goto ret;
 144 //                                      }
 145 //                              }
 146                                 goto skip_it;
 147                         }
 148
 149                         if (h->nlmsg_type == NLMSG_DONE) {
 150                                 goto ret_0;
 151                         }
 152                         if (h->nlmsg_type == NLMSG_ERROR) {
 153                                 struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
 154                                 if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
 155                                         bb_error_msg("ERROR truncated");
 156                                 } else {
 157                                         errno = -l_err->error;
 158                                         bb_perror_msg("RTNETLINK answers");
 159                                 }
 160                                 goto ret;
 161                         }
 162                         err = filter(&nladdr, h, arg1);
 163                         if (err < 0) {
 164                                 retval = err;
 165                                 goto ret;
 166                         }
 167
 168  skip_it:
 169                         h = NLMSG_NEXT(h, status);
 170                 }
 171                 if (msg.msg_flags & MSG_TRUNC) {
 172                         bb_error_msg("message truncated");
 173                         continue;
 174                 }
 175                 if (status) {
 176                         bb_error_msg_and_die("remnant of size %d!", status);
 177                 }
 178         } /* while (1) */
 179  ret_0:
 180         retval++; /* = 0 */
 181  ret:
 182         free(buf);
 183         return retval;
 184 }
 185
 186 int FAST_FUNC xrtnl_dump_filter(struct rtnl_handle *rth,
 187                 int (*filter)(const struct sockaddr_nl *, struct nlmsghdr *, void *) FAST_FUNC,
 188                 void *arg1)
 189 {
 190         int ret = rtnl_dump_filter(rth, filter, arg1/*, NULL, NULL*/);
 191         if (ret < 0)
 192                 bb_error_msg_and_die("dump terminated");
 193         return ret;
 194 }
 195
 196 int FAST_FUNC rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
 197                 pid_t peer, unsigned groups,
 198                 struct nlmsghdr *answer,
 199                 int (*junk)(struct sockaddr_nl *, struct nlmsghdr *, void *),
 200                 void *jarg)
 201 {
 202 /* bbox doesn't use parameters no. 3, 4, 6, 7, they are stubbed out */
 203 #define peer   0
 204 #define groups 0
 205 #define junk   NULL
 206 #define jarg   NULL
 207         int retval = -1;
 208         int status;
 209         unsigned seq;
 210         struct nlmsghdr *h;
 211         struct sockaddr_nl nladdr;
 212         struct iovec iov = { (void*)n, n->nlmsg_len };
 213         char   *buf = xmalloc(8*1024); /* avoid big stack buffer */
 214         struct msghdr msg = {
 215                 (void*)&nladdr, sizeof(nladdr),
 216                 &iov, 1,
 217                 NULL, 0,
 218                 0
 219         };
 220
 221         memset(&nladdr, 0, sizeof(nladdr));
 222         nladdr.nl_family = AF_NETLINK;
 223 //      nladdr.nl_pid = peer;
 224 //      nladdr.nl_groups = groups;
 225
 226         n->nlmsg_seq = seq = ++rtnl->seq;
 227         if (answer == NULL) {
 228                 n->nlmsg_flags |= NLM_F_ACK;
 229         }
 230         status = sendmsg(rtnl->fd, &msg, 0);
 231
 232         if (status < 0) {
 233                 bb_perror_msg("can't talk to rtnetlink");
 234                 goto ret;
 235         }
 236
 237         iov.iov_base = buf;
 238
 239         while (1) {
 240                 iov.iov_len = 8*1024;
 241                 status = recvmsg(rtnl->fd, &msg, 0);
 242
 243                 if (status < 0) {
 244                         if (errno == EINTR) {
 245                                 continue;
 246                         }
 247                         bb_perror_msg("OVERRUN");
 248                         continue;
 249                 }
 250                 if (status == 0) {
 251                         bb_error_msg("EOF on netlink");
 252                         goto ret;
 253                 }
 254                 if (msg.msg_namelen != sizeof(nladdr)) {
 255                         bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
 256                 }
 257                 for (h = (struct nlmsghdr*)buf; status >= (int)sizeof(*h); ) {
 258 //                      int l_err;
 259                         int len = h->nlmsg_len;
 260                         int l = len - sizeof(*h);
 261
 262                         if (l < 0 || len > status) {
 263                                 if (msg.msg_flags & MSG_TRUNC) {
 264                                         bb_error_msg("truncated message");
 265                                         goto ret;
 266                                 }
 267                                 bb_error_msg_and_die("malformed message: len=%d!", len);
 268                         }
 269
 270                         if (nladdr.nl_pid != peer ||
 271                             h->nlmsg_pid != rtnl->local.nl_pid ||
 272                             h->nlmsg_seq != seq
 273                         ) {
 274 //                              if (junk) {
 275 //                                      l_err = junk(&nladdr, h, jarg);
 276 //                                      if (l_err < 0) {
 277 //                                              retval = l_err;
 278 //                                              goto ret;
 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 < (int)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                                                 goto ret_0;
 295                                         }
 296                                         bb_perror_msg("RTNETLINK answers");
 297                                 }
 298                                 goto ret;
 299                         }
 300                         if (answer) {
 301                                 memcpy(answer, h, h->nlmsg_len);
 302                                 goto ret_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         } /* while (1) */
 318  ret_0:
 319         retval++; /* = 0 */
 320  ret:
 321         free(buf);
 322         return retval;
 323 }
 324
 325 int FAST_FUNC addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data)
 326 {
 327         int len = RTA_LENGTH(4);
 328         struct rtattr *rta;
 329
 330         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
 331                 return -1;
 332         }
 333         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 334         rta->rta_type = type;
 335         rta->rta_len = len;
 336         move_to_unaligned32(RTA_DATA(rta), data);
 337         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 338         return 0;
 339 }
 340
 341 int FAST_FUNC addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
 342 {
 343         int len = RTA_LENGTH(alen);
 344         struct rtattr *rta;
 345
 346         if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
 347                 return -1;
 348         }
 349         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
 350         rta->rta_type = type;
 351         rta->rta_len = len;
 352         memcpy(RTA_DATA(rta), data, alen);
 353         n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
 354         return 0;
 355 }
 356
 357 int FAST_FUNC rta_addattr32(struct rtattr *rta, int maxlen, int type, uint32_t data)
 358 {
 359         int len = RTA_LENGTH(4);
 360         struct rtattr *subrta;
 361
 362         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 363                 return -1;
 364         }
 365         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 366         subrta->rta_type = type;
 367         subrta->rta_len = len;
 368         move_to_unaligned32(RTA_DATA(subrta), data);
 369         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 370         return 0;
 371 }
 372
 373 int FAST_FUNC rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
 374 {
 375         struct rtattr *subrta;
 376         int len = RTA_LENGTH(alen);
 377
 378         if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
 379                 return -1;
 380         }
 381         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
 382         subrta->rta_type = type;
 383         subrta->rta_len = len;
 384         memcpy(RTA_DATA(subrta), data, alen);
 385         rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
 386         return 0;
 387 }
 388
 389
 390 void FAST_FUNC parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
 391 {
 392         while (RTA_OK(rta, len)) {
 393                 if (rta->rta_type <= max) {
 394                         tb[rta->rta_type] = rta;
 395                 }
 396                 rta = RTA_NEXT(rta, len);
 397         }
 398         if (len) {
 399                 bb_error_msg("deficit %d, rta_len=%d!", len, rta->rta_len);
 400         }
 401 }