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                 if (iface->ifindex == ifi->ifi_index)
 317                         continue;
 318
 319                 iface->ifindex = ifi->ifi_index;
 320                 event_info.iface = iface;
 321                 call_netevent_handler_list(NETEV_IFINDEX_CHANGE, &event_info);
 322         }
 323
 324         return NL_OK;
 325 }
 326
 327 static int handle_rtm_route(struct nlmsghdr *hdr, bool add)
 328 {
 329         struct rtmsg *rtm = nlmsg_data(hdr);
 330         struct nlattr *nla[__RTA_MAX];
 331         struct interface *iface;
 332         struct netevent_handler_info event_info;
 333         int ifindex = 0;
 334
 335         if (!nlmsg_valid_hdr(hdr, sizeof(*rtm)) || rtm->rtm_family != AF_INET6)
 336                 return NL_SKIP;
 337
 338         nlmsg_parse(hdr, sizeof(*rtm), nla, __RTA_MAX - 1, NULL);
 339
 340         memset(&event_info, 0, sizeof(event_info));
 341         event_info.rt.dst_len = rtm->rtm_dst_len;
 342
 343         if (nla[RTA_DST])
 344                 nla_memcpy(&event_info.rt.dst, nla[RTA_DST],
 345                                 sizeof(event_info.rt.dst));
 346
 347         if (nla[RTA_OIF])
 348                 ifindex = nla_get_u32(nla[RTA_OIF]);
 349
 350         if (nla[RTA_GATEWAY])
 351                 nla_memcpy(&event_info.rt.gateway, nla[RTA_GATEWAY],
 352                                 sizeof(event_info.rt.gateway));
 353
 354         avl_for_each_element(&interfaces, iface, avl) {
 355                 if (ifindex && iface->ifindex != ifindex)
 356                         continue;
 357
 358                 event_info.iface = ifindex ? iface : NULL;
 359                 call_netevent_handler_list(add ? NETEV_ROUTE6_ADD : NETEV_ROUTE6_DEL,
 360                                                 &event_info);
 361         }
 362
 363         return NL_OK;
 364 }
 365
 366 static int handle_rtm_addr(struct nlmsghdr *hdr, bool add)
 367 {
 368         struct ifaddrmsg *ifa = nlmsg_data(hdr);
 369         struct nlattr *nla[__IFA_MAX];
 370         struct interface *iface;
 371         struct netevent_handler_info event_info;
 372         char buf[INET6_ADDRSTRLEN];
 373
 374         if (!nlmsg_valid_hdr(hdr, sizeof(*ifa)) ||
 375                         (ifa->ifa_family != AF_INET6 &&
 376                          ifa->ifa_family != AF_INET))
 377                 return NL_SKIP;
 378
 379         memset(&event_info, 0, sizeof(event_info));
 380
 381         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 382
 383         if (ifa->ifa_family == AF_INET6) {
 384                 if (!nla[IFA_ADDRESS])
 385                         return NL_SKIP;
 386
 387                 nla_memcpy(&event_info.addr, nla[IFA_ADDRESS], sizeof(event_info.addr));
 388
 389                 if (IN6_IS_ADDR_LINKLOCAL(&event_info.addr) || IN6_IS_ADDR_MULTICAST(&event_info.addr))
 390                         return NL_SKIP;
 391
 392                 inet_ntop(AF_INET6, &event_info.addr, buf, sizeof(buf));
 393
 394                 avl_for_each_element(&interfaces, iface, avl) {
 395                         if (iface->ifindex != (int)ifa->ifa_index)
 396                                 continue;
 397
 398                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 399                                         buf, iface->name);
 400
 401                         event_info.iface = iface;
 402                         call_netevent_handler_list(add ? NETEV_ADDR6_ADD : NETEV_ADDR6_DEL,
 403                                                         &event_info);
 404                 }
 405
 406                 refresh_iface_addr6(ifa->ifa_index);
 407         } else {
 408                 if (!nla[IFA_LOCAL])
 409                         return NL_SKIP;
 410
 411                 nla_memcpy(&event_info.addr, nla[IFA_LOCAL], sizeof(event_info.addr));
 412
 413                 inet_ntop(AF_INET, &event_info.addr, buf, sizeof(buf));
 414
 415                 avl_for_each_element(&interfaces, iface, avl) {
 416                         if (iface->ifindex != (int)ifa->ifa_index)
 417                                 continue;
 418
 419                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 420                                         buf, iface->name);
 421
 422                         event_info.iface = iface;
 423                         call_netevent_handler_list(add ? NETEV_ADDR_ADD : NETEV_ADDR_DEL,
 424                                                         &event_info);
 425                 }
 426
 427                 refresh_iface_addr4(ifa->ifa_index);
 428         }
 429
 430         return NL_OK;
 431 }
 432
 433 static int handle_rtm_neigh(struct nlmsghdr *hdr, bool add)
 434 {
 435         struct ndmsg *ndm = nlmsg_data(hdr);
 436         struct nlattr *nla[__NDA_MAX];
 437         struct interface *iface;
 438         struct netevent_handler_info event_info;
 439         char buf[INET6_ADDRSTRLEN];
 440
 441         if (!nlmsg_valid_hdr(hdr, sizeof(*ndm)) ||
 442                         ndm->ndm_family != AF_INET6)
 443                 return NL_SKIP;
 444
 445         nlmsg_parse(hdr, sizeof(*ndm), nla, __NDA_MAX - 1, NULL);
 446         if (!nla[NDA_DST])
 447                 return NL_SKIP;
 448
 449         memset(&event_info, 0, sizeof(event_info));
 450
 451         nla_memcpy(&event_info.neigh.dst, nla[NDA_DST], sizeof(event_info.neigh.dst));
 452
 453         if (IN6_IS_ADDR_LINKLOCAL(&event_info.neigh.dst) ||
 454                         IN6_IS_ADDR_MULTICAST(&event_info.neigh.dst))
 455                 return NL_SKIP;
 456
 457         inet_ntop(AF_INET6, &event_info.neigh.dst, buf, sizeof(buf));
 458
 459         avl_for_each_element(&interfaces, iface, avl) {
 460                 if (iface->ifindex != ndm->ndm_ifindex)
 461                         continue;
 462
 463                 syslog(LOG_DEBUG, "Netlink %s %s on %s", true ? "newneigh" : "delneigh",
 464                                 buf, iface->name);
 465
 466                 event_info.iface = iface;
 467                 event_info.neigh.state = ndm->ndm_state;
 468                 event_info.neigh.flags = ndm->ndm_flags;
 469
 470                 call_netevent_handler_list(add ? NETEV_NEIGH6_ADD : NETEV_NEIGH6_DEL,
 471                                                 &event_info);
 472         }
 473
 474         return NL_OK;
 475 }
 476
 477 /* Handler for neighbor cache entries from the kernel. This is our source
 478  * to learn and unlearn hosts on interfaces. */
 479 static int cb_rtnl_valid(struct nl_msg *msg, _unused void *arg)
 480 {
 481         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 482         int ret = NL_SKIP;
 483         bool add = false;
 484
 485         switch (hdr->nlmsg_type) {
 486         case RTM_NEWLINK:
 487                 ret = handle_rtm_link(hdr);
 488                 break;
 489
 490         case RTM_NEWROUTE:
 491                 add = true;
 492                 /* fall through */
 493         case RTM_DELROUTE:
 494                 ret = handle_rtm_route(hdr, add);
 495                 break;
 496
 497         case RTM_NEWADDR:
 498                 add = true;
 499                 /* fall through */
 500         case RTM_DELADDR:
 501                 ret = handle_rtm_addr(hdr, add);
 502                 break;
 503
 504         case RTM_NEWNEIGH:
 505                 add = true;
 506                 /* fall through */
 507         case RTM_DELNEIGH:
 508                 ret = handle_rtm_neigh(hdr, add);
 509                 break;
 510
 511         default:
 512                 break;
 513         }
 514
 515         return ret;
 516 }
 517
 518 static void catch_rtnl_err(struct odhcpd_event *e, int error)
 519 {
 520         struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
 521
 522         if (error != ENOBUFS)
 523                 goto err;
 524
 525         /* Double netlink event buffer size */
 526         ev_sock->sock_bufsize *= 2;
 527
 528         if (nl_socket_set_buffer_size(ev_sock->sock, ev_sock->sock_bufsize, 0))
 529                 goto err;
 530
 531         netlink_dump_addr_table(true);
 532         return;
 533
 534 err:
 535         odhcpd_deregister(e);
 536 }
 537
 538 static struct nl_sock *create_socket(int protocol)
 539 {
 540         struct nl_sock *nl_sock;
 541
 542         nl_sock = nl_socket_alloc();
 543         if (!nl_sock)
 544                 goto err;
 545
 546         if (nl_connect(nl_sock, protocol) < 0)
 547                 goto err;
 548
 549         return nl_sock;
 550
 551 err:
 552         if (nl_sock)
 553                 nl_socket_free(nl_sock);
 554
 555         return NULL;
 556 }
 557
 558
 559 struct addr_info {
 560         int ifindex;
 561         int af;
 562         struct odhcpd_ipaddr **addrs;
 563         int pending;
 564         ssize_t ret;
 565 };
 566
 567
 568 static int cb_addr_valid(struct nl_msg *msg, void *arg)
 569 {
 570         struct addr_info *ctxt = (struct addr_info *)arg;
 571         struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 572         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 573         struct ifaddrmsg *ifa;
 574         struct nlattr *nla[__IFA_MAX], *nla_addr = NULL;
 575
 576         if (hdr->nlmsg_type != RTM_NEWADDR)
 577                 return NL_SKIP;
 578
 579         ifa = NLMSG_DATA(hdr);
 580         if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
 581                         (ctxt->af != ifa->ifa_family) ||
 582                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 583                 return NL_SKIP;
 584
 585         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 586
 587         switch (ifa->ifa_family) {
 588         case AF_INET6:
 589                 if (nla[IFA_ADDRESS])
 590                         nla_addr = nla[IFA_ADDRESS];
 591                 break;
 592
 593         case AF_INET:
 594                 if (nla[IFA_LOCAL])
 595                         nla_addr = nla[IFA_LOCAL];
 596                 break;
 597
 598         default:
 599                 break;
 600         }
 601         if (!nla_addr)
 602                 return NL_SKIP;
 603
 604         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 605         if (!addrs)
 606                 return NL_SKIP;
 607
 608         memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
 609         addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 610
 611         nla_memcpy(&addrs[ctxt->ret].addr, nla_addr,
 612                         sizeof(addrs[ctxt->ret].addr));
 613
 614         if (nla[IFA_BROADCAST])
 615                 nla_memcpy(&addrs[ctxt->ret].broadcast, nla[IFA_BROADCAST],
 616                                 sizeof(addrs[ctxt->ret].broadcast));
 617
 618         if (nla[IFA_CACHEINFO]) {
 619                 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 620
 621                 addrs[ctxt->ret].preferred = ifc->ifa_prefered;
 622                 addrs[ctxt->ret].valid = ifc->ifa_valid;
 623         }
 624
 625         if (ifa->ifa_flags & IFA_F_DEPRECATED)
 626                 addrs[ctxt->ret].preferred = 0;
 627
 628         ctxt->ret++;
 629         *(ctxt->addrs) = addrs;
 630
 631         return NL_OK;
 632 }
 633
 634
 635 static int cb_addr_finish(_unused struct nl_msg *msg, void *arg)
 636 {
 637         struct addr_info *ctxt = (struct addr_info *)arg;
 638
 639         ctxt->pending = 0;
 640
 641         return NL_STOP;
 642 }
 643
 644
 645 static int cb_addr_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 646                 void *arg)
 647 {
 648         struct addr_info *ctxt = (struct addr_info *)arg;
 649
 650         ctxt->pending = 0;
 651         ctxt->ret = err->error;
 652
 653         return NL_STOP;
 654 }
 655
 656
 657 static int prefix_cmp(const void *va, const void *vb)
 658 {
 659         const struct odhcpd_ipaddr *a = va, *b = vb;
 660         int ret = 0;
 661
 662         if (a->prefix == b->prefix) {
 663                 ret = (ntohl(a->addr.in.s_addr) < ntohl(b->addr.in.s_addr)) ? 1 :
 664                         (ntohl(a->addr.in.s_addr) > ntohl(b->addr.in.s_addr)) ? -1 : 0;
 665         } else
 666                 ret = a->prefix < b->prefix ? 1 : -1;
 667
 668         return ret;
 669 }
 670
 671
 672 /* compare IPv6 prefixes */
 673 static int prefix6_cmp(const void *va, const void *vb)
 674 {
 675         const struct odhcpd_ipaddr *a = va, *b = vb;
 676         uint32_t a_pref = IN6_IS_ADDR_ULA(&a->addr.in6) ? 1 : a->preferred;
 677         uint32_t b_pref = IN6_IS_ADDR_ULA(&b->addr.in6) ? 1 : b->preferred;
 678         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 679 }
 680
 681
 682 /* Detect an IPV6-address currently assigned to the given interface */
 683 ssize_t netlink_get_interface_addrs(int ifindex, bool v6, struct odhcpd_ipaddr **addrs)
 684 {
 685         struct nl_msg *msg;
 686         struct ifaddrmsg ifa = {
 687                 .ifa_family = v6? AF_INET6: AF_INET,
 688                 .ifa_prefixlen = 0,
 689                 .ifa_flags = 0,
 690                 .ifa_scope = 0,
 691                 .ifa_index = ifindex, };
 692         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 693         struct addr_info ctxt = {
 694                 .ifindex = ifindex,
 695                 .af = v6? AF_INET6: AF_INET,
 696                 .addrs = addrs,
 697                 .ret = 0,
 698                 .pending = 1,
 699         };
 700
 701         if (!cb) {
 702                 ctxt.ret = -1;
 703                 goto out;
 704         }
 705
 706         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 707
 708         if (!msg) {
 709                 ctxt.ret = - 1;
 710                 goto out;
 711         }
 712
 713         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 714
 715         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_addr_valid, &ctxt);
 716         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_addr_finish, &ctxt);
 717         nl_cb_err(cb, NL_CB_CUSTOM, cb_addr_error, &ctxt);
 718
 719         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 720         if (ctxt.ret < 0)
 721                 goto free;
 722
 723         ctxt.ret = 0;
 724         while (ctxt.pending > 0)
 725                 nl_recvmsgs(rtnl_socket, cb);
 726
 727         if (ctxt.ret <= 0)
 728                 goto free;
 729
 730         time_t now = odhcpd_time();
 731         struct odhcpd_ipaddr *addr = *addrs;
 732
 733         qsort(addr, ctxt.ret, sizeof(*addr), v6 ? prefix6_cmp : prefix_cmp);
 734
 735         for (ssize_t i = 0; i < ctxt.ret; ++i) {
 736                 if (addr[i].preferred < UINT32_MAX - now)
 737                         addr[i].preferred += now;
 738
 739                 if (addr[i].valid < UINT32_MAX - now)
 740                         addr[i].valid += now;
 741         }
 742
 743 free:
 744         nlmsg_free(msg);
 745 out:
 746         nl_cb_put(cb);
 747
 748         return ctxt.ret;
 749 }
 750
 751
 752 struct neigh_info {
 753         int ifindex;
 754         int pending;
 755         const struct in6_addr *addr;
 756         int ret;
 757 };
 758
 759
 760 static int cb_proxy_neigh_valid(struct nl_msg *msg, void *arg)
 761 {
 762         struct neigh_info *ctxt = (struct neigh_info *)arg;
 763         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 764         struct ndmsg *ndm;
 765         struct nlattr *nla_dst;
 766
 767         if (hdr->nlmsg_type != RTM_NEWNEIGH)
 768                 return NL_SKIP;
 769
 770         ndm = NLMSG_DATA(hdr);
 771         if (ndm->ndm_family != AF_INET6 ||
 772                         (ctxt->ifindex && ndm->ndm_ifindex != ctxt->ifindex))
 773                 return NL_SKIP;
 774
 775         if (!(ndm->ndm_flags & NTF_PROXY))
 776                 return NL_SKIP;
 777
 778         nla_dst = nlmsg_find_attr(hdr, sizeof(*ndm), NDA_DST);
 779         if (!nla_dst)
 780                 return NL_SKIP;
 781
 782         if (nla_memcmp(nla_dst,ctxt->addr, 16) == 0)
 783                 ctxt->ret = 1;
 784
 785         return NL_OK;
 786 }
 787
 788
 789 static int cb_proxy_neigh_finish(_unused struct nl_msg *msg, void *arg)
 790 {
 791         struct neigh_info *ctxt = (struct neigh_info *)arg;
 792
 793         ctxt->pending = 0;
 794
 795         return NL_STOP;
 796 }
 797
 798
 799 static int cb_proxy_neigh_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 800                 void *arg)
 801 {
 802         struct neigh_info *ctxt = (struct neigh_info *)arg;
 803
 804         ctxt->pending = 0;
 805         ctxt->ret = err->error;
 806
 807         return NL_STOP;
 808 }
 809
 810 /* Detect an IPV6-address proxy neighbor for the given interface */
 811 int netlink_get_interface_proxy_neigh(int ifindex, const struct in6_addr *addr)
 812 {
 813         struct nl_msg *msg;
 814         struct ndmsg ndm = {
 815                 .ndm_family = AF_INET6,
 816                 .ndm_flags = NTF_PROXY,
 817                 .ndm_ifindex = ifindex,
 818         };
 819         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 820         struct neigh_info ctxt = {
 821                 .ifindex = ifindex,
 822                 .addr = addr,
 823                 .ret = 0,
 824                 .pending = 1,
 825         };
 826
 827         if (!cb) {
 828                 ctxt.ret = -1;
 829                 goto out;
 830         }
 831
 832         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_MATCH);
 833
 834         if (!msg) {
 835                 ctxt.ret = -1;
 836                 goto out;
 837         }
 838
 839         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 840         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 841
 842         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_proxy_neigh_valid, &ctxt);
 843         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_proxy_neigh_finish, &ctxt);
 844         nl_cb_err(cb, NL_CB_CUSTOM, cb_proxy_neigh_error, &ctxt);
 845
 846         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 847         if (ctxt.ret < 0)
 848                 goto free;
 849
 850         while (ctxt.pending > 0)
 851                 nl_recvmsgs(rtnl_socket, cb);
 852
 853 free:
 854         nlmsg_free(msg);
 855 out:
 856         nl_cb_put(cb);
 857
 858         return ctxt.ret;
 859 }
 860
 861
 862 int netlink_setup_route(const struct in6_addr *addr, const int prefixlen,
 863                 const int ifindex, const struct in6_addr *gw,
 864                 const uint32_t metric, const bool add)
 865 {
 866         struct nl_msg *msg;
 867         struct rtmsg rtm = {
 868                 .rtm_family = AF_INET6,
 869                 .rtm_dst_len = prefixlen,
 870                 .rtm_src_len = 0,
 871                 .rtm_table = RT_TABLE_MAIN,
 872                 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
 873                 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
 874                 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
 875         };
 876         int ret = 0;
 877
 878         msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
 879                                         add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
 880         if (!msg)
 881                 return -1;
 882
 883         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 884
 885         nla_put(msg, RTA_DST, sizeof(*addr), addr);
 886         nla_put_u32(msg, RTA_OIF, ifindex);
 887         nla_put_u32(msg, RTA_PRIORITY, metric);
 888
 889         if (gw)
 890                 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
 891
 892         ret = nl_send_auto_complete(rtnl_socket, msg);
 893         nlmsg_free(msg);
 894
 895         if (ret < 0)
 896                 return ret;
 897
 898         return nl_wait_for_ack(rtnl_socket);
 899 }
 900
 901
 902 int netlink_setup_proxy_neigh(const struct in6_addr *addr,
 903                 const int ifindex, const bool add)
 904 {
 905         struct nl_msg *msg;
 906         struct ndmsg ndm = {
 907                 .ndm_family = AF_INET6,
 908                 .ndm_flags = NTF_PROXY,
 909                 .ndm_ifindex = ifindex,
 910         };
 911         int ret = 0, flags = NLM_F_REQUEST;
 912
 913         if (add)
 914                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 915
 916         msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
 917         if (!msg)
 918                 return -1;
 919
 920         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 921
 922         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 923
 924         ret = nl_send_auto_complete(rtnl_socket, msg);
 925         nlmsg_free(msg);
 926
 927         if (ret < 0)
 928                 return ret;
 929
 930         return nl_wait_for_ack(rtnl_socket);
 931 }
 932
 933
 934 int netlink_setup_addr(struct odhcpd_ipaddr *addr,
 935                 const int ifindex, const bool v6, const bool add)
 936 {
 937         struct nl_msg *msg;
 938         struct ifaddrmsg ifa = {
 939                 .ifa_family = v6 ? AF_INET6 : AF_INET,
 940                 .ifa_prefixlen = addr->prefix,
 941                 .ifa_flags = 0,
 942                 .ifa_scope = 0,
 943                 .ifa_index = ifindex, };
 944         int ret = 0, flags = NLM_F_REQUEST;
 945
 946         if (add)
 947                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 948
 949         msg = nlmsg_alloc_simple(add ? RTM_NEWADDR : RTM_DELADDR, 0);
 950         if (!msg)
 951                 return -1;
 952
 953         nlmsg_append(msg, &ifa, sizeof(ifa), flags);
 954         nla_put(msg, IFA_LOCAL, v6 ? 16 : 4, &addr->addr);
 955         if (v6) {
 956                 struct ifa_cacheinfo cinfo = {  .ifa_prefered = 0xffffffffU,
 957                                                 .ifa_valid = 0xffffffffU,
 958                                                 .cstamp = 0,
 959                                                 .tstamp = 0 };
 960                 time_t now = odhcpd_time();
 961
 962                 if (addr->preferred) {
 963                         int64_t preferred = addr->preferred - now;
 964                         if (preferred < 0)
 965                                 preferred = 0;
 966                         else if (preferred > UINT32_MAX)
 967                                 preferred = UINT32_MAX;
 968
 969                         cinfo.ifa_prefered = preferred;
 970                 }
 971
 972                 if (addr->valid) {
 973                         int64_t valid = addr->valid - now;
 974                         if (valid <= 0) {
 975                                 nlmsg_free(msg);
 976                                 return -1;
 977                         }
 978                         else if (valid > UINT32_MAX)
 979                                 valid = UINT32_MAX;
 980
 981                         cinfo.ifa_valid = valid;
 982                 }
 983
 984                 nla_put(msg, IFA_CACHEINFO, sizeof(cinfo), &cinfo);
 985
 986                 nla_put_u32(msg, IFA_FLAGS, IFA_F_NOPREFIXROUTE);
 987         } else {
 988                 if (addr->broadcast.s_addr)
 989                         nla_put_u32(msg, IFA_BROADCAST, addr->broadcast.s_addr);
 990         }
 991
 992         ret = nl_send_auto_complete(rtnl_socket, msg);
 993         nlmsg_free(msg);
 994
 995         if (ret < 0)
 996                 return ret;
 997
 998         return nl_wait_for_ack(rtnl_socket);
 999 }
1000
1001 void netlink_dump_neigh_table(const bool proxy)
1002 {
1003         struct nl_msg *msg;
1004         struct ndmsg ndm = {
1005                 .ndm_family = AF_INET6,
1006                 .ndm_flags = proxy ? NTF_PROXY : 0,
1007         };
1008
1009         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP);
1010         if (!msg)
1011                 return;
1012
1013         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
1014
1015         nl_send_auto_complete(rtnl_event.sock, msg);
1016
1017         nlmsg_free(msg);
1018 }
1019
1020 void netlink_dump_addr_table(const bool v6)
1021 {
1022         struct nl_msg *msg;
1023         struct ifaddrmsg ifa = {
1024                 .ifa_family = v6 ? AF_INET6 : AF_INET,
1025         };
1026
1027         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
1028         if (!msg)
1029                 return;
1030
1031         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
1032
1033         nl_send_auto_complete(rtnl_event.sock, msg);
1034
1035         nlmsg_free(msg);
1036 }