src/netlink.c

   1 /**
   2  * Copyright (C) 2017 Hans Dedecker <dedeckeh@gmail.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <errno.h>
  16 #include <string.h>
  17 #include <syslog.h>
  18
  19 #include <linux/netlink.h>
  20 #include <linux/if_addr.h>
  21 #include <linux/neighbour.h>
  22 #include <linux/rtnetlink.h>
  23
  24 #include <netlink/msg.h>
  25 #include <netlink/socket.h>
  26 #include <netlink/attr.h>
  27
  28 #include <arpa/inet.h>
  29 #include <libubox/list.h>
  30
  31 #include "odhcpd.h"
  32
  33 struct event_socket {
  34         struct odhcpd_event ev;
  35         struct nl_sock *sock;
  36         int sock_bufsize;
  37 };
  38
  39 static void handle_rtnl_event(struct odhcpd_event *ev);
  40 static int cb_rtnl_valid(struct nl_msg *msg, void *arg);
  41 static void catch_rtnl_err(struct odhcpd_event *e, int error);
  42 static struct nl_sock *create_socket(int protocol);
  43
  44 static struct nl_sock *rtnl_socket = NULL;
  45 struct list_head netevent_handler_list = LIST_HEAD_INIT(netevent_handler_list);
  46 static struct event_socket rtnl_event = {
  47         .ev = {
  48                 .uloop = {.fd = - 1, },
  49                 .handle_dgram = NULL,
  50                 .handle_error = catch_rtnl_err,
  51                 .recv_msgs = handle_rtnl_event,
  52         },
  53         .sock = NULL,
  54         .sock_bufsize = 133120,
  55 };
  56
  57 int netlink_init(void)
  58 {
  59         rtnl_socket = create_socket(NETLINK_ROUTE);
  60         if (!rtnl_socket) {
  61                 syslog(LOG_ERR, "Unable to open nl socket: %m");
  62                 goto err;
  63         }
  64
  65         rtnl_event.sock = create_socket(NETLINK_ROUTE);
  66         if (!rtnl_event.sock) {
  67                 syslog(LOG_ERR, "Unable to open nl event socket: %m");
  68                 goto err;
  69         }
  70
  71         rtnl_event.ev.uloop.fd = nl_socket_get_fd(rtnl_event.sock);
  72
  73         if (nl_socket_set_buffer_size(rtnl_event.sock, rtnl_event.sock_bufsize, 0))
  74                 goto err;
  75
  76         nl_socket_disable_seq_check(rtnl_event.sock);
  77
  78         nl_socket_modify_cb(rtnl_event.sock, NL_CB_VALID, NL_CB_CUSTOM,
  79                         cb_rtnl_valid, NULL);
  80
  81         /* Receive IPv4 address, IPv6 address, IPv6 routes and neighbor events */
  82         if (nl_socket_add_memberships(rtnl_event.sock, RTNLGRP_IPV4_IFADDR,
  83                                 RTNLGRP_IPV6_IFADDR, RTNLGRP_IPV6_ROUTE,
  84                                 RTNLGRP_NEIGH, RTNLGRP_LINK, 0))
  85                 goto err;
  86
  87         odhcpd_register(&rtnl_event.ev);
  88
  89         return 0;
  90
  91 err:
  92         if (rtnl_socket) {
  93                 nl_socket_free(rtnl_socket);
  94                 rtnl_socket = NULL;
  95         }
  96
  97         if (rtnl_event.sock) {
  98                 nl_socket_free(rtnl_event.sock);
  99                 rtnl_event.sock = NULL;
 100                 rtnl_event.ev.uloop.fd = -1;
 101         }
 102
 103         return -1;
 104 }
 105
 106
 107 int netlink_add_netevent_handler(struct netevent_handler *handler)
 108 {
 109         if (!handler->cb)
 110                 return -1;
 111
 112         list_add(&handler->head, &netevent_handler_list);
 113
 114         return 0;
 115 }
 116
 117 static void call_netevent_handler_list(unsigned long event, struct netevent_handler_info *info)
 118 {
 119         struct netevent_handler *handler;
 120
 121         list_for_each_entry(handler, &netevent_handler_list, head)
 122                 handler->cb(event, info);
 123 }
 124
 125 static void handle_rtnl_event(struct odhcpd_event *e)
 126 {
 127         struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
 128
 129         nl_recvmsgs_default(ev_sock->sock);
 130 }
 131
 132 static void refresh_iface_addr4(int ifindex)
 133 {
 134         struct odhcpd_ipaddr *addr = NULL;
 135         struct interface *iface;
 136         ssize_t len = netlink_get_interface_addrs(ifindex, false, &addr);
 137         bool change = false;
 138
 139         if (len < 0)
 140                 return;
 141
 142         avl_for_each_element(&interfaces, iface, avl) {
 143                 struct netevent_handler_info event_info;
 144
 145                 if (iface->ifindex != ifindex)
 146                         continue;
 147
 148                 memset(&event_info, 0, sizeof(event_info));
 149                 event_info.iface = iface;
 150                 event_info.addrs_old.addrs = iface->addr4;
 151                 event_info.addrs_old.len = iface->addr4_len;
 152
 153                 if (!change) {
 154                         change = len != (ssize_t)iface->addr4_len;
 155                         for (ssize_t i = 0; !change && i < len; ++i) {
 156                                 if (addr[i].addr.in.s_addr != iface->addr4[i].addr.in.s_addr)
 157                                         change = true;
 158                         }
 159                 }
 160
 161                 iface->addr4 = addr;
 162                 iface->addr4_len = len;
 163
 164                 if (change)
 165                         call_netevent_handler_list(NETEV_ADDRLIST_CHANGE, &event_info);
 166
 167                 free(event_info.addrs_old.addrs);
 168
 169                 if (!len)
 170                         continue;
 171
 172                 addr = malloc(len * sizeof(*addr));
 173                 if (!addr)
 174                         break;
 175
 176                 memcpy(addr, iface->addr4, len * sizeof(*addr));
 177         }
 178
 179         free(addr);
 180 }
 181
 182 static void refresh_iface_addr6(int ifindex)
 183 {
 184         struct odhcpd_ipaddr *addr = NULL;
 185         struct interface *iface;
 186         ssize_t len = netlink_get_interface_addrs(ifindex, true, &addr);
 187         time_t now = odhcpd_time();
 188         bool change = false;
 189
 190         if (len < 0)
 191                 return;
 192
 193         avl_for_each_element(&interfaces, iface, avl) {
 194                 struct netevent_handler_info event_info;
 195
 196                 if (iface->ifindex != ifindex)
 197                         continue;
 198
 199                 memset(&event_info, 0, sizeof(event_info));
 200                 event_info.iface = iface;
 201                 event_info.addrs_old.addrs = iface->addr6;
 202                 event_info.addrs_old.len = iface->addr6_len;
 203
 204                 if (!change) {
 205                         change = len != (ssize_t)iface->addr6_len;
 206                         for (ssize_t i = 0; !change && i < len; ++i) {
 207                                 if (!IN6_ARE_ADDR_EQUAL(&addr[i].addr.in6, &iface->addr6[i].addr.in6) ||
 208                                     addr[i].prefix != iface->addr6[i].prefix ||
 209                                     (addr[i].preferred > (uint32_t)now) != (iface->addr6[i].preferred > (uint32_t)now) ||
 210                                     addr[i].valid < iface->addr6[i].valid || addr[i].preferred < iface->addr6[i].preferred)
 211                                         change = true;
 212                         }
 213
 214                         if (change) {
 215                                 /*
 216                                  * Keep track on removed prefixes, so we could advertise them as invalid
 217                                  * for at least a couple of times.
 218                                  *
 219                                  * RFC7084 § 4.3 :
 220                                  *    L-13:  If the delegated prefix changes, i.e., the current prefix is
 221                                  *           replaced with a new prefix without any overlapping time
 222                                  *           period, then the IPv6 CE router MUST immediately advertise the
 223                                  *           old prefix with a Preferred Lifetime of zero and a Valid
 224                                  *           Lifetime of either a) zero or b) the lower of the current
 225                                  *           Valid Lifetime and two hours (which must be decremented in
 226                                  *           real time) in a Router Advertisement message as described in
 227                                  *           Section 5.5.3, (e) of [RFC4862].
 228                                  */
 229
 230                                 for (size_t i = 0; i < iface->addr6_len; ++i) {
 231                                         bool removed = true;
 232
 233                                         if (iface->addr6[i].valid <= (uint32_t)now)
 234                                                 continue;
 235
 236                                         for (ssize_t j = 0; removed && j < len; ++j) {
 237                                                 size_t plen = min(addr[j].prefix, iface->addr6[i].prefix);
 238
 239                                                 if (odhcpd_bmemcmp(&addr[j].addr.in6, &iface->addr6[i].addr.in6, plen) == 0)
 240                                                         removed = false;
 241                                         }
 242
 243                                         for (size_t j = 0; removed && j < iface->invalid_addr6_len; ++j) {
 244                                                 size_t plen = min(iface->invalid_addr6[j].prefix, iface->addr6[i].prefix);
 245
 246                                                 if (odhcpd_bmemcmp(&iface->invalid_addr6[j].addr.in6, &iface->addr6[i].addr.in6, plen) == 0)
 247                                                         removed = false;
 248                                         }
 249
 250                                         if (removed) {
 251                                                 size_t pos = iface->invalid_addr6_len;
 252                                                 struct odhcpd_ipaddr *new_invalid_addr6 = realloc(iface->invalid_addr6,
 253                                                                 sizeof(*iface->invalid_addr6) * (pos + 1));
 254
 255                                                 if (!new_invalid_addr6)
 256                                                         break;
 257
 258                                                 iface->invalid_addr6 = new_invalid_addr6;
 259                                                 iface->invalid_addr6_len++;
 260                                                 memcpy(&iface->invalid_addr6[pos], &iface->addr6[i], sizeof(*iface->invalid_addr6));
 261                                                 iface->invalid_addr6[pos].valid = iface->invalid_addr6[pos].preferred = (uint32_t)now;
 262
 263                                                 if (iface->invalid_addr6[pos].prefix < 64)
 264                                                         iface->invalid_addr6[pos].prefix = 64;
 265                                         }
 266                                 }
 267                         }
 268                 }
 269
 270                 iface->addr6 = addr;
 271                 iface->addr6_len = len;
 272
 273                 if (change)
 274                         call_netevent_handler_list(NETEV_ADDR6LIST_CHANGE, &event_info);
 275
 276                 free(event_info.addrs_old.addrs);
 277
 278                 if (!len)
 279                         continue;
 280
 281                 addr = malloc(len * sizeof(*addr));
 282                 if (!addr)
 283                         break;
 284
 285                 memcpy(addr, iface->addr6, len * sizeof(*addr));
 286         }
 287
 288         free(addr);
 289 }
 290
 291 static int handle_rtm_link(struct nlmsghdr *hdr)
 292 {
 293         struct ifinfomsg *ifi = nlmsg_data(hdr);
 294         struct nlattr *nla[__IFLA_MAX];
 295         struct interface *iface;
 296         struct netevent_handler_info event_info;
 297         const char *ifname;
 298
 299         memset(&event_info, 0, sizeof(event_info));
 300
 301         if (!nlmsg_valid_hdr(hdr, sizeof(*ifi)) || ifi->ifi_family != AF_UNSPEC)
 302                 return NL_SKIP;
 303
 304         nlmsg_parse(hdr, sizeof(*ifi), nla, __IFLA_MAX - 1, NULL);
 305         if (!nla[IFLA_IFNAME])
 306                 return NL_SKIP;
 307
 308         ifname = nla_get_string(nla[IFLA_IFNAME]);
 309
 310         avl_for_each_element(&interfaces, iface, avl) {
 311                 if (strcmp(iface->ifname, ifname))
 312                         continue;
 313
 314                 iface->ifflags = ifi->ifi_flags;
 315
 316                 /*
 317                  * Assume for link event of the same index, that link changed
 318                  * and reload services to enable or disable them based on the
 319                  * RUNNING state of the interface.
 320                  */
 321                 if (iface->ifindex == ifi->ifi_index) {
 322                         reload_services(iface);
 323                         continue;
 324                 }
 325
 326                 iface->ifindex = ifi->ifi_index;
 327                 event_info.iface = iface;
 328                 call_netevent_handler_list(NETEV_IFINDEX_CHANGE, &event_info);
 329         }
 330
 331         return NL_OK;
 332 }
 333
 334 static int handle_rtm_route(struct nlmsghdr *hdr, bool add)
 335 {
 336         struct rtmsg *rtm = nlmsg_data(hdr);
 337         struct nlattr *nla[__RTA_MAX];
 338         struct interface *iface;
 339         struct netevent_handler_info event_info;
 340         int ifindex = 0;
 341
 342         if (!nlmsg_valid_hdr(hdr, sizeof(*rtm)) || rtm->rtm_family != AF_INET6)
 343                 return NL_SKIP;
 344
 345         nlmsg_parse(hdr, sizeof(*rtm), nla, __RTA_MAX - 1, NULL);
 346
 347         memset(&event_info, 0, sizeof(event_info));
 348         event_info.rt.dst_len = rtm->rtm_dst_len;
 349
 350         if (nla[RTA_DST])
 351                 nla_memcpy(&event_info.rt.dst, nla[RTA_DST],
 352                                 sizeof(event_info.rt.dst));
 353
 354         if (nla[RTA_OIF])
 355                 ifindex = nla_get_u32(nla[RTA_OIF]);
 356
 357         if (nla[RTA_GATEWAY])
 358                 nla_memcpy(&event_info.rt.gateway, nla[RTA_GATEWAY],
 359                                 sizeof(event_info.rt.gateway));
 360
 361         avl_for_each_element(&interfaces, iface, avl) {
 362                 if (ifindex && iface->ifindex != ifindex)
 363                         continue;
 364
 365                 event_info.iface = ifindex ? iface : NULL;
 366                 call_netevent_handler_list(add ? NETEV_ROUTE6_ADD : NETEV_ROUTE6_DEL,
 367                                                 &event_info);
 368         }
 369
 370         return NL_OK;
 371 }
 372
 373 static int handle_rtm_addr(struct nlmsghdr *hdr, bool add)
 374 {
 375         struct ifaddrmsg *ifa = nlmsg_data(hdr);
 376         struct nlattr *nla[__IFA_MAX];
 377         struct interface *iface;
 378         struct netevent_handler_info event_info;
 379         char buf[INET6_ADDRSTRLEN];
 380
 381         if (!nlmsg_valid_hdr(hdr, sizeof(*ifa)) ||
 382                         (ifa->ifa_family != AF_INET6 &&
 383                          ifa->ifa_family != AF_INET))
 384                 return NL_SKIP;
 385
 386         memset(&event_info, 0, sizeof(event_info));
 387
 388         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 389
 390         if (ifa->ifa_family == AF_INET6) {
 391                 if (!nla[IFA_ADDRESS])
 392                         return NL_SKIP;
 393
 394                 nla_memcpy(&event_info.addr, nla[IFA_ADDRESS], sizeof(event_info.addr));
 395
 396                 if (IN6_IS_ADDR_MULTICAST(&event_info.addr))
 397                         return NL_SKIP;
 398
 399                 inet_ntop(AF_INET6, &event_info.addr, buf, sizeof(buf));
 400
 401                 avl_for_each_element(&interfaces, iface, avl) {
 402                         if (iface->ifindex != (int)ifa->ifa_index)
 403                                 continue;
 404
 405                         if (add && IN6_IS_ADDR_LINKLOCAL(&event_info.addr)) {
 406                                 iface->have_link_local = true;
 407                                 return NL_SKIP;
 408                         }
 409
 410                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 411                                         buf, iface->name);
 412
 413                         event_info.iface = iface;
 414                         call_netevent_handler_list(add ? NETEV_ADDR6_ADD : NETEV_ADDR6_DEL,
 415                                                         &event_info);
 416                 }
 417
 418                 refresh_iface_addr6(ifa->ifa_index);
 419         } else {
 420                 if (!nla[IFA_LOCAL])
 421                         return NL_SKIP;
 422
 423                 nla_memcpy(&event_info.addr, nla[IFA_LOCAL], sizeof(event_info.addr));
 424
 425                 inet_ntop(AF_INET, &event_info.addr, buf, sizeof(buf));
 426
 427                 avl_for_each_element(&interfaces, iface, avl) {
 428                         if (iface->ifindex != (int)ifa->ifa_index)
 429                                 continue;
 430
 431                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 432                                         buf, iface->name);
 433
 434                         event_info.iface = iface;
 435                         call_netevent_handler_list(add ? NETEV_ADDR_ADD : NETEV_ADDR_DEL,
 436                                                         &event_info);
 437                 }
 438
 439                 refresh_iface_addr4(ifa->ifa_index);
 440         }
 441
 442         return NL_OK;
 443 }
 444
 445 static int handle_rtm_neigh(struct nlmsghdr *hdr, bool add)
 446 {
 447         struct ndmsg *ndm = nlmsg_data(hdr);
 448         struct nlattr *nla[__NDA_MAX];
 449         struct interface *iface;
 450         struct netevent_handler_info event_info;
 451         char buf[INET6_ADDRSTRLEN];
 452
 453         if (!nlmsg_valid_hdr(hdr, sizeof(*ndm)) ||
 454                         ndm->ndm_family != AF_INET6)
 455                 return NL_SKIP;
 456
 457         nlmsg_parse(hdr, sizeof(*ndm), nla, __NDA_MAX - 1, NULL);
 458         if (!nla[NDA_DST])
 459                 return NL_SKIP;
 460
 461         memset(&event_info, 0, sizeof(event_info));
 462
 463         nla_memcpy(&event_info.neigh.dst, nla[NDA_DST], sizeof(event_info.neigh.dst));
 464
 465         if (IN6_IS_ADDR_LINKLOCAL(&event_info.neigh.dst) ||
 466                         IN6_IS_ADDR_MULTICAST(&event_info.neigh.dst))
 467                 return NL_SKIP;
 468
 469         inet_ntop(AF_INET6, &event_info.neigh.dst, buf, sizeof(buf));
 470
 471         avl_for_each_element(&interfaces, iface, avl) {
 472                 if (iface->ifindex != ndm->ndm_ifindex)
 473                         continue;
 474
 475                 syslog(LOG_DEBUG, "Netlink %s %s on %s", true ? "newneigh" : "delneigh",
 476                                 buf, iface->name);
 477
 478                 event_info.iface = iface;
 479                 event_info.neigh.state = ndm->ndm_state;
 480                 event_info.neigh.flags = ndm->ndm_flags;
 481
 482                 call_netevent_handler_list(add ? NETEV_NEIGH6_ADD : NETEV_NEIGH6_DEL,
 483                                                 &event_info);
 484         }
 485
 486         return NL_OK;
 487 }
 488
 489 /* Handler for neighbor cache entries from the kernel. This is our source
 490  * to learn and unlearn hosts on interfaces. */
 491 static int cb_rtnl_valid(struct nl_msg *msg, _unused void *arg)
 492 {
 493         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 494         int ret = NL_SKIP;
 495         bool add = false;
 496
 497         switch (hdr->nlmsg_type) {
 498         case RTM_NEWLINK:
 499                 ret = handle_rtm_link(hdr);
 500                 break;
 501
 502         case RTM_NEWROUTE:
 503                 add = true;
 504                 /* fall through */
 505         case RTM_DELROUTE:
 506                 ret = handle_rtm_route(hdr, add);
 507                 break;
 508
 509         case RTM_NEWADDR:
 510                 add = true;
 511                 /* fall through */
 512         case RTM_DELADDR:
 513                 ret = handle_rtm_addr(hdr, add);
 514                 break;
 515
 516         case RTM_NEWNEIGH:
 517                 add = true;
 518                 /* fall through */
 519         case RTM_DELNEIGH:
 520                 ret = handle_rtm_neigh(hdr, add);
 521                 break;
 522
 523         default:
 524                 break;
 525         }
 526
 527         return ret;
 528 }
 529
 530 static void catch_rtnl_err(struct odhcpd_event *e, int error)
 531 {
 532         struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
 533
 534         if (error != ENOBUFS)
 535                 goto err;
 536
 537         /* Double netlink event buffer size */
 538         ev_sock->sock_bufsize *= 2;
 539
 540         if (nl_socket_set_buffer_size(ev_sock->sock, ev_sock->sock_bufsize, 0))
 541                 goto err;
 542
 543         netlink_dump_addr_table(true);
 544         return;
 545
 546 err:
 547         odhcpd_deregister(e);
 548 }
 549
 550 static struct nl_sock *create_socket(int protocol)
 551 {
 552         struct nl_sock *nl_sock;
 553
 554         nl_sock = nl_socket_alloc();
 555         if (!nl_sock)
 556                 goto err;
 557
 558         if (nl_connect(nl_sock, protocol) < 0)
 559                 goto err;
 560
 561         return nl_sock;
 562
 563 err:
 564         if (nl_sock)
 565                 nl_socket_free(nl_sock);
 566
 567         return NULL;
 568 }
 569
 570
 571 struct addr_info {
 572         int ifindex;
 573         int af;
 574         struct odhcpd_ipaddr **addrs;
 575         int pending;
 576         ssize_t ret;
 577 };
 578
 579
 580 static int cb_addr_valid(struct nl_msg *msg, void *arg)
 581 {
 582         struct addr_info *ctxt = (struct addr_info *)arg;
 583         struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 584         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 585         struct ifaddrmsg *ifa;
 586         struct nlattr *nla[__IFA_MAX], *nla_addr = NULL;
 587
 588         if (hdr->nlmsg_type != RTM_NEWADDR)
 589                 return NL_SKIP;
 590
 591         ifa = NLMSG_DATA(hdr);
 592         if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
 593                         (ctxt->af != ifa->ifa_family) ||
 594                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 595                 return NL_SKIP;
 596
 597         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 598
 599         switch (ifa->ifa_family) {
 600         case AF_INET6:
 601                 if (nla[IFA_ADDRESS])
 602                         nla_addr = nla[IFA_ADDRESS];
 603                 break;
 604
 605         case AF_INET:
 606                 if (nla[IFA_LOCAL])
 607                         nla_addr = nla[IFA_LOCAL];
 608                 break;
 609
 610         default:
 611                 break;
 612         }
 613         if (!nla_addr)
 614                 return NL_SKIP;
 615
 616         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 617         if (!addrs)
 618                 return NL_SKIP;
 619
 620         memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
 621         addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 622
 623         nla_memcpy(&addrs[ctxt->ret].addr, nla_addr,
 624                         sizeof(addrs[ctxt->ret].addr));
 625
 626         if (nla[IFA_BROADCAST])
 627                 nla_memcpy(&addrs[ctxt->ret].broadcast, nla[IFA_BROADCAST],
 628                                 sizeof(addrs[ctxt->ret].broadcast));
 629
 630         if (nla[IFA_CACHEINFO]) {
 631                 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 632
 633                 addrs[ctxt->ret].preferred = ifc->ifa_prefered;
 634                 addrs[ctxt->ret].valid = ifc->ifa_valid;
 635         }
 636
 637         if (ifa->ifa_flags & IFA_F_DEPRECATED)
 638                 addrs[ctxt->ret].preferred = 0;
 639
 640         if (ifa->ifa_family == AF_INET6 &&
 641             ifa->ifa_flags & IFA_F_TENTATIVE)
 642                 addrs[ctxt->ret].tentative = true;
 643
 644         ctxt->ret++;
 645         *(ctxt->addrs) = addrs;
 646
 647         return NL_OK;
 648 }
 649
 650
 651 static int cb_addr_finish(_unused struct nl_msg *msg, void *arg)
 652 {
 653         struct addr_info *ctxt = (struct addr_info *)arg;
 654
 655         ctxt->pending = 0;
 656
 657         return NL_STOP;
 658 }
 659
 660
 661 static int cb_addr_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 662                 void *arg)
 663 {
 664         struct addr_info *ctxt = (struct addr_info *)arg;
 665
 666         ctxt->pending = 0;
 667         ctxt->ret = err->error;
 668
 669         return NL_STOP;
 670 }
 671
 672
 673 static int prefix_cmp(const void *va, const void *vb)
 674 {
 675         const struct odhcpd_ipaddr *a = va, *b = vb;
 676         int ret = 0;
 677
 678         if (a->prefix == b->prefix) {
 679                 ret = (ntohl(a->addr.in.s_addr) < ntohl(b->addr.in.s_addr)) ? 1 :
 680                         (ntohl(a->addr.in.s_addr) > ntohl(b->addr.in.s_addr)) ? -1 : 0;
 681         } else
 682                 ret = a->prefix < b->prefix ? 1 : -1;
 683
 684         return ret;
 685 }
 686
 687
 688 /* compare IPv6 prefixes */
 689 static int prefix6_cmp(const void *va, const void *vb)
 690 {
 691         const struct odhcpd_ipaddr *a = va, *b = vb;
 692         uint32_t a_pref = IN6_IS_ADDR_ULA(&a->addr.in6) ? 1 : a->preferred;
 693         uint32_t b_pref = IN6_IS_ADDR_ULA(&b->addr.in6) ? 1 : b->preferred;
 694         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 695 }
 696
 697
 698 /* Detect an IPV6-address currently assigned to the given interface */
 699 ssize_t netlink_get_interface_addrs(int ifindex, bool v6, struct odhcpd_ipaddr **addrs)
 700 {
 701         struct nl_msg *msg;
 702         struct ifaddrmsg ifa = {
 703                 .ifa_family = v6? AF_INET6: AF_INET,
 704                 .ifa_prefixlen = 0,
 705                 .ifa_flags = 0,
 706                 .ifa_scope = 0,
 707                 .ifa_index = ifindex, };
 708         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 709         struct addr_info ctxt = {
 710                 .ifindex = ifindex,
 711                 .af = v6? AF_INET6: AF_INET,
 712                 .addrs = addrs,
 713                 .ret = 0,
 714                 .pending = 1,
 715         };
 716
 717         if (!cb) {
 718                 ctxt.ret = -1;
 719                 goto out;
 720         }
 721
 722         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 723
 724         if (!msg) {
 725                 ctxt.ret = - 1;
 726                 goto out;
 727         }
 728
 729         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 730
 731         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_addr_valid, &ctxt);
 732         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_addr_finish, &ctxt);
 733         nl_cb_err(cb, NL_CB_CUSTOM, cb_addr_error, &ctxt);
 734
 735         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 736         if (ctxt.ret < 0)
 737                 goto free;
 738
 739         ctxt.ret = 0;
 740         while (ctxt.pending > 0)
 741                 nl_recvmsgs(rtnl_socket, cb);
 742
 743         if (ctxt.ret <= 0)
 744                 goto free;
 745
 746         time_t now = odhcpd_time();
 747         struct odhcpd_ipaddr *addr = *addrs;
 748
 749         qsort(addr, ctxt.ret, sizeof(*addr), v6 ? prefix6_cmp : prefix_cmp);
 750
 751         for (ssize_t i = 0; i < ctxt.ret; ++i) {
 752                 if (addr[i].preferred < UINT32_MAX - now)
 753                         addr[i].preferred += now;
 754
 755                 if (addr[i].valid < UINT32_MAX - now)
 756                         addr[i].valid += now;
 757         }
 758
 759 free:
 760         nlmsg_free(msg);
 761 out:
 762         nl_cb_put(cb);
 763
 764         return ctxt.ret;
 765 }
 766
 767
 768 static int cb_linklocal_valid(struct nl_msg *msg, void *arg)
 769 {
 770         struct addr_info *ctxt = (struct addr_info *)arg;
 771         struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 772         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 773         struct ifaddrmsg *ifa;
 774         struct nlattr *nla[__IFA_MAX], *nla_addr = NULL;
 775         struct in6_addr addr;
 776
 777         if (hdr->nlmsg_type != RTM_NEWADDR)
 778                 return NL_SKIP;
 779
 780         ifa = NLMSG_DATA(hdr);
 781         if (ifa->ifa_scope != RT_SCOPE_LINK ||
 782                         (ctxt->af != ifa->ifa_family) ||
 783                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 784                 return NL_SKIP;
 785
 786         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 787
 788         switch (ifa->ifa_family) {
 789         case AF_INET6:
 790                 if (nla[IFA_ADDRESS])
 791                         nla_addr = nla[IFA_ADDRESS];
 792                 break;
 793
 794         default:
 795                 break;
 796         }
 797         if (!nla_addr)
 798                 return NL_SKIP;
 799
 800         nla_memcpy(&addr, nla_addr, sizeof(addr));
 801
 802         if (!IN6_IS_ADDR_LINKLOCAL(&addr))
 803                 return NL_SKIP;
 804
 805         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 806         if (!addrs)
 807                 return NL_SKIP;
 808
 809         memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
 810
 811         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 812         if (!addrs)
 813                 return NL_SKIP;
 814
 815
 816         memcpy(&addrs[ctxt->ret].addr, &addr, sizeof(addrs[ctxt->ret].addr));
 817
 818         if (ifa->ifa_flags & IFA_F_TENTATIVE)
 819                 addrs[ctxt->ret].tentative = true;
 820
 821         ctxt->ret++;
 822         *(ctxt->addrs) = addrs;
 823
 824         return NL_OK;
 825 }
 826
 827
 828 static int cb_linklocal_finish(_unused struct nl_msg *msg, void *arg)
 829 {
 830         struct addr_info *ctxt = (struct addr_info *)arg;
 831
 832         ctxt->pending = 0;
 833
 834         return NL_STOP;
 835 }
 836
 837
 838 static int cb_linklocal_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 839                 void *arg)
 840 {
 841         struct addr_info *ctxt = (struct addr_info *)arg;
 842
 843         ctxt->pending = 0;
 844         ctxt->ret = err->error;
 845
 846         return NL_STOP;
 847 }
 848
 849
 850 /* Detect a link local IPV6-address currently assigned to the given interface */
 851 ssize_t netlink_get_interface_linklocal(int ifindex, struct odhcpd_ipaddr **addrs)
 852 {
 853         struct nl_msg *msg;
 854         struct ifaddrmsg ifa = {
 855                 .ifa_family = AF_INET6,
 856                 .ifa_prefixlen = 0,
 857                 .ifa_flags = 0,
 858                 .ifa_scope = 0,
 859                 .ifa_index = ifindex, };
 860         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 861         struct addr_info ctxt = {
 862                 .ifindex = ifindex,
 863                 .af = AF_INET6,
 864                 .addrs = addrs,
 865                 .ret = 0,
 866                 .pending = 1,
 867         };
 868
 869         if (!cb) {
 870                 ctxt.ret = -1;
 871                 goto out;
 872         }
 873
 874         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 875
 876         if (!msg) {
 877                 ctxt.ret = - 1;
 878                 goto out;
 879         }
 880
 881         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 882
 883         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_linklocal_valid, &ctxt);
 884         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_linklocal_finish, &ctxt);
 885         nl_cb_err(cb, NL_CB_CUSTOM, cb_linklocal_error, &ctxt);
 886
 887         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 888         if (ctxt.ret < 0)
 889                 goto free;
 890
 891         ctxt.ret = 0;
 892         while (ctxt.pending > 0)
 893                 nl_recvmsgs(rtnl_socket, cb);
 894
 895         if (ctxt.ret <= 0)
 896                 goto free;
 897
 898 free:
 899         nlmsg_free(msg);
 900 out:
 901         nl_cb_put(cb);
 902
 903         return ctxt.ret;
 904 }
 905
 906
 907 struct neigh_info {
 908         int ifindex;
 909         int pending;
 910         const struct in6_addr *addr;
 911         int ret;
 912 };
 913
 914
 915 static int cb_proxy_neigh_valid(struct nl_msg *msg, void *arg)
 916 {
 917         struct neigh_info *ctxt = (struct neigh_info *)arg;
 918         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 919         struct ndmsg *ndm;
 920         struct nlattr *nla_dst;
 921
 922         if (hdr->nlmsg_type != RTM_NEWNEIGH)
 923                 return NL_SKIP;
 924
 925         ndm = NLMSG_DATA(hdr);
 926         if (ndm->ndm_family != AF_INET6 ||
 927                         (ctxt->ifindex && ndm->ndm_ifindex != ctxt->ifindex))
 928                 return NL_SKIP;
 929
 930         if (!(ndm->ndm_flags & NTF_PROXY))
 931                 return NL_SKIP;
 932
 933         nla_dst = nlmsg_find_attr(hdr, sizeof(*ndm), NDA_DST);
 934         if (!nla_dst)
 935                 return NL_SKIP;
 936
 937         if (nla_memcmp(nla_dst,ctxt->addr, 16) == 0)
 938                 ctxt->ret = 1;
 939
 940         return NL_OK;
 941 }
 942
 943
 944 static int cb_proxy_neigh_finish(_unused struct nl_msg *msg, void *arg)
 945 {
 946         struct neigh_info *ctxt = (struct neigh_info *)arg;
 947
 948         ctxt->pending = 0;
 949
 950         return NL_STOP;
 951 }
 952
 953
 954 static int cb_proxy_neigh_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 955                 void *arg)
 956 {
 957         struct neigh_info *ctxt = (struct neigh_info *)arg;
 958
 959         ctxt->pending = 0;
 960         ctxt->ret = err->error;
 961
 962         return NL_STOP;
 963 }
 964
 965 /* Detect an IPV6-address proxy neighbor for the given interface */
 966 int netlink_get_interface_proxy_neigh(int ifindex, const struct in6_addr *addr)
 967 {
 968         struct nl_msg *msg;
 969         struct ndmsg ndm = {
 970                 .ndm_family = AF_INET6,
 971                 .ndm_flags = NTF_PROXY,
 972                 .ndm_ifindex = ifindex,
 973         };
 974         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 975         struct neigh_info ctxt = {
 976                 .ifindex = ifindex,
 977                 .addr = addr,
 978                 .ret = 0,
 979                 .pending = 1,
 980         };
 981
 982         if (!cb) {
 983                 ctxt.ret = -1;
 984                 goto out;
 985         }
 986
 987         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_MATCH);
 988
 989         if (!msg) {
 990                 ctxt.ret = -1;
 991                 goto out;
 992         }
 993
 994         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 995         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 996
 997         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_proxy_neigh_valid, &ctxt);
 998         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_proxy_neigh_finish, &ctxt);
 999         nl_cb_err(cb, NL_CB_CUSTOM, cb_proxy_neigh_error, &ctxt);
1000
1001         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
1002         if (ctxt.ret < 0)
1003                 goto free;
1004
1005         while (ctxt.pending > 0)
1006                 nl_recvmsgs(rtnl_socket, cb);
1007
1008 free:
1009         nlmsg_free(msg);
1010 out:
1011         nl_cb_put(cb);
1012
1013         return ctxt.ret;
1014 }
1015
1016
1017 int netlink_setup_route(const struct in6_addr *addr, const int prefixlen,
1018                 const int ifindex, const struct in6_addr *gw,
1019                 const uint32_t metric, const bool add)
1020 {
1021         struct nl_msg *msg;
1022         struct rtmsg rtm = {
1023                 .rtm_family = AF_INET6,
1024                 .rtm_dst_len = prefixlen,
1025                 .rtm_src_len = 0,
1026                 .rtm_table = RT_TABLE_MAIN,
1027                 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
1028                 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
1029                 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
1030         };
1031         int ret = 0;
1032
1033         msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
1034                                         add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
1035         if (!msg)
1036                 return -1;
1037
1038         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
1039
1040         nla_put(msg, RTA_DST, sizeof(*addr), addr);
1041         nla_put_u32(msg, RTA_OIF, ifindex);
1042         nla_put_u32(msg, RTA_PRIORITY, metric);
1043
1044         if (gw)
1045                 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
1046
1047         ret = nl_send_auto_complete(rtnl_socket, msg);
1048         nlmsg_free(msg);
1049
1050         if (ret < 0)
1051                 return ret;
1052
1053         return nl_wait_for_ack(rtnl_socket);
1054 }
1055
1056
1057 int netlink_setup_proxy_neigh(const struct in6_addr *addr,
1058                 const int ifindex, const bool add)
1059 {
1060         struct nl_msg *msg;
1061         struct ndmsg ndm = {
1062                 .ndm_family = AF_INET6,
1063                 .ndm_flags = NTF_PROXY,
1064                 .ndm_ifindex = ifindex,
1065         };
1066         int ret = 0, flags = NLM_F_REQUEST;
1067
1068         if (add)
1069                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
1070
1071         msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
1072         if (!msg)
1073                 return -1;
1074
1075         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
1076
1077         nla_put(msg, NDA_DST, sizeof(*addr), addr);
1078
1079         ret = nl_send_auto_complete(rtnl_socket, msg);
1080         nlmsg_free(msg);
1081
1082         if (ret < 0)
1083                 return ret;
1084
1085         return nl_wait_for_ack(rtnl_socket);
1086 }
1087
1088
1089 int netlink_setup_addr(struct odhcpd_ipaddr *addr,
1090                 const int ifindex, const bool v6, const bool add)
1091 {
1092         struct nl_msg *msg;
1093         struct ifaddrmsg ifa = {
1094                 .ifa_family = v6 ? AF_INET6 : AF_INET,
1095                 .ifa_prefixlen = addr->prefix,
1096                 .ifa_flags = 0,
1097                 .ifa_scope = 0,
1098                 .ifa_index = ifindex, };
1099         int ret = 0, flags = NLM_F_REQUEST;
1100
1101         if (add)
1102                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
1103
1104         msg = nlmsg_alloc_simple(add ? RTM_NEWADDR : RTM_DELADDR, 0);
1105         if (!msg)
1106                 return -1;
1107
1108         nlmsg_append(msg, &ifa, sizeof(ifa), flags);
1109         nla_put(msg, IFA_LOCAL, v6 ? 16 : 4, &addr->addr);
1110         if (v6) {
1111                 struct ifa_cacheinfo cinfo = {  .ifa_prefered = 0xffffffffU,
1112                                                 .ifa_valid = 0xffffffffU,
1113                                                 .cstamp = 0,
1114                                                 .tstamp = 0 };
1115                 time_t now = odhcpd_time();
1116
1117                 if (addr->preferred) {
1118                         int64_t preferred = addr->preferred - now;
1119                         if (preferred < 0)
1120                                 preferred = 0;
1121                         else if (preferred > UINT32_MAX)
1122                                 preferred = UINT32_MAX;
1123
1124                         cinfo.ifa_prefered = preferred;
1125                 }
1126
1127                 if (addr->valid) {
1128                         int64_t valid = addr->valid - now;
1129                         if (valid <= 0) {
1130                                 nlmsg_free(msg);
1131                                 return -1;
1132                         }
1133                         else if (valid > UINT32_MAX)
1134                                 valid = UINT32_MAX;
1135
1136                         cinfo.ifa_valid = valid;
1137                 }
1138
1139                 nla_put(msg, IFA_CACHEINFO, sizeof(cinfo), &cinfo);
1140
1141                 nla_put_u32(msg, IFA_FLAGS, IFA_F_NOPREFIXROUTE);
1142         } else {
1143                 if (addr->broadcast.s_addr)
1144                         nla_put_u32(msg, IFA_BROADCAST, addr->broadcast.s_addr);
1145         }
1146
1147         ret = nl_send_auto_complete(rtnl_socket, msg);
1148         nlmsg_free(msg);
1149
1150         if (ret < 0)
1151                 return ret;
1152
1153         return nl_wait_for_ack(rtnl_socket);
1154 }
1155
1156 void netlink_dump_neigh_table(const bool proxy)
1157 {
1158         struct nl_msg *msg;
1159         struct ndmsg ndm = {
1160                 .ndm_family = AF_INET6,
1161                 .ndm_flags = proxy ? NTF_PROXY : 0,
1162         };
1163
1164         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP);
1165         if (!msg)
1166                 return;
1167
1168         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
1169
1170         nl_send_auto_complete(rtnl_event.sock, msg);
1171
1172         nlmsg_free(msg);
1173 }
1174
1175 void netlink_dump_addr_table(const bool v6)
1176 {
1177         struct nl_msg *msg;
1178         struct ifaddrmsg ifa = {
1179                 .ifa_family = v6 ? AF_INET6 : AF_INET,
1180         };
1181
1182         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
1183         if (!msg)
1184                 return;
1185
1186         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
1187
1188         nl_send_auto_complete(rtnl_event.sock, msg);
1189
1190         nlmsg_free(msg);
1191 }