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_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                         if (add && IN6_IS_ADDR_LINKLOCAL(&event_info.addr)) {
 399                                 iface->have_link_local = true;
 400                                 return NL_SKIP;
 401                         }
 402
 403                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 404                                         buf, iface->name);
 405
 406                         event_info.iface = iface;
 407                         call_netevent_handler_list(add ? NETEV_ADDR6_ADD : NETEV_ADDR6_DEL,
 408                                                         &event_info);
 409                 }
 410
 411                 refresh_iface_addr6(ifa->ifa_index);
 412         } else {
 413                 if (!nla[IFA_LOCAL])
 414                         return NL_SKIP;
 415
 416                 nla_memcpy(&event_info.addr, nla[IFA_LOCAL], sizeof(event_info.addr));
 417
 418                 inet_ntop(AF_INET, &event_info.addr, buf, sizeof(buf));
 419
 420                 avl_for_each_element(&interfaces, iface, avl) {
 421                         if (iface->ifindex != (int)ifa->ifa_index)
 422                                 continue;
 423
 424                         syslog(LOG_DEBUG, "Netlink %s %s on %s", add ? "newaddr" : "deladdr",
 425                                         buf, iface->name);
 426
 427                         event_info.iface = iface;
 428                         call_netevent_handler_list(add ? NETEV_ADDR_ADD : NETEV_ADDR_DEL,
 429                                                         &event_info);
 430                 }
 431
 432                 refresh_iface_addr4(ifa->ifa_index);
 433         }
 434
 435         return NL_OK;
 436 }
 437
 438 static int handle_rtm_neigh(struct nlmsghdr *hdr, bool add)
 439 {
 440         struct ndmsg *ndm = nlmsg_data(hdr);
 441         struct nlattr *nla[__NDA_MAX];
 442         struct interface *iface;
 443         struct netevent_handler_info event_info;
 444         char buf[INET6_ADDRSTRLEN];
 445
 446         if (!nlmsg_valid_hdr(hdr, sizeof(*ndm)) ||
 447                         ndm->ndm_family != AF_INET6)
 448                 return NL_SKIP;
 449
 450         nlmsg_parse(hdr, sizeof(*ndm), nla, __NDA_MAX - 1, NULL);
 451         if (!nla[NDA_DST])
 452                 return NL_SKIP;
 453
 454         memset(&event_info, 0, sizeof(event_info));
 455
 456         nla_memcpy(&event_info.neigh.dst, nla[NDA_DST], sizeof(event_info.neigh.dst));
 457
 458         if (IN6_IS_ADDR_LINKLOCAL(&event_info.neigh.dst) ||
 459                         IN6_IS_ADDR_MULTICAST(&event_info.neigh.dst))
 460                 return NL_SKIP;
 461
 462         inet_ntop(AF_INET6, &event_info.neigh.dst, buf, sizeof(buf));
 463
 464         avl_for_each_element(&interfaces, iface, avl) {
 465                 if (iface->ifindex != ndm->ndm_ifindex)
 466                         continue;
 467
 468                 syslog(LOG_DEBUG, "Netlink %s %s on %s", true ? "newneigh" : "delneigh",
 469                                 buf, iface->name);
 470
 471                 event_info.iface = iface;
 472                 event_info.neigh.state = ndm->ndm_state;
 473                 event_info.neigh.flags = ndm->ndm_flags;
 474
 475                 call_netevent_handler_list(add ? NETEV_NEIGH6_ADD : NETEV_NEIGH6_DEL,
 476                                                 &event_info);
 477         }
 478
 479         return NL_OK;
 480 }
 481
 482 /* Handler for neighbor cache entries from the kernel. This is our source
 483  * to learn and unlearn hosts on interfaces. */
 484 static int cb_rtnl_valid(struct nl_msg *msg, _unused void *arg)
 485 {
 486         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 487         int ret = NL_SKIP;
 488         bool add = false;
 489
 490         switch (hdr->nlmsg_type) {
 491         case RTM_NEWLINK:
 492                 ret = handle_rtm_link(hdr);
 493                 break;
 494
 495         case RTM_NEWROUTE:
 496                 add = true;
 497                 /* fall through */
 498         case RTM_DELROUTE:
 499                 ret = handle_rtm_route(hdr, add);
 500                 break;
 501
 502         case RTM_NEWADDR:
 503                 add = true;
 504                 /* fall through */
 505         case RTM_DELADDR:
 506                 ret = handle_rtm_addr(hdr, add);
 507                 break;
 508
 509         case RTM_NEWNEIGH:
 510                 add = true;
 511                 /* fall through */
 512         case RTM_DELNEIGH:
 513                 ret = handle_rtm_neigh(hdr, add);
 514                 break;
 515
 516         default:
 517                 break;
 518         }
 519
 520         return ret;
 521 }
 522
 523 static void catch_rtnl_err(struct odhcpd_event *e, int error)
 524 {
 525         struct event_socket *ev_sock = container_of(e, struct event_socket, ev);
 526
 527         if (error != ENOBUFS)
 528                 goto err;
 529
 530         /* Double netlink event buffer size */
 531         ev_sock->sock_bufsize *= 2;
 532
 533         if (nl_socket_set_buffer_size(ev_sock->sock, ev_sock->sock_bufsize, 0))
 534                 goto err;
 535
 536         netlink_dump_addr_table(true);
 537         return;
 538
 539 err:
 540         odhcpd_deregister(e);
 541 }
 542
 543 static struct nl_sock *create_socket(int protocol)
 544 {
 545         struct nl_sock *nl_sock;
 546
 547         nl_sock = nl_socket_alloc();
 548         if (!nl_sock)
 549                 goto err;
 550
 551         if (nl_connect(nl_sock, protocol) < 0)
 552                 goto err;
 553
 554         return nl_sock;
 555
 556 err:
 557         if (nl_sock)
 558                 nl_socket_free(nl_sock);
 559
 560         return NULL;
 561 }
 562
 563
 564 struct addr_info {
 565         int ifindex;
 566         int af;
 567         struct odhcpd_ipaddr **addrs;
 568         int pending;
 569         ssize_t ret;
 570 };
 571
 572
 573 static int cb_addr_valid(struct nl_msg *msg, void *arg)
 574 {
 575         struct addr_info *ctxt = (struct addr_info *)arg;
 576         struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 577         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 578         struct ifaddrmsg *ifa;
 579         struct nlattr *nla[__IFA_MAX], *nla_addr = NULL;
 580
 581         if (hdr->nlmsg_type != RTM_NEWADDR)
 582                 return NL_SKIP;
 583
 584         ifa = NLMSG_DATA(hdr);
 585         if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
 586                         (ctxt->af != ifa->ifa_family) ||
 587                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 588                 return NL_SKIP;
 589
 590         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 591
 592         switch (ifa->ifa_family) {
 593         case AF_INET6:
 594                 if (nla[IFA_ADDRESS])
 595                         nla_addr = nla[IFA_ADDRESS];
 596                 break;
 597
 598         case AF_INET:
 599                 if (nla[IFA_LOCAL])
 600                         nla_addr = nla[IFA_LOCAL];
 601                 break;
 602
 603         default:
 604                 break;
 605         }
 606         if (!nla_addr)
 607                 return NL_SKIP;
 608
 609         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 610         if (!addrs)
 611                 return NL_SKIP;
 612
 613         memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
 614         addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 615
 616         nla_memcpy(&addrs[ctxt->ret].addr, nla_addr,
 617                         sizeof(addrs[ctxt->ret].addr));
 618
 619         if (nla[IFA_BROADCAST])
 620                 nla_memcpy(&addrs[ctxt->ret].broadcast, nla[IFA_BROADCAST],
 621                                 sizeof(addrs[ctxt->ret].broadcast));
 622
 623         if (nla[IFA_CACHEINFO]) {
 624                 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 625
 626                 addrs[ctxt->ret].preferred = ifc->ifa_prefered;
 627                 addrs[ctxt->ret].valid = ifc->ifa_valid;
 628         }
 629
 630         if (ifa->ifa_flags & IFA_F_DEPRECATED)
 631                 addrs[ctxt->ret].preferred = 0;
 632
 633         if (ifa->ifa_family == AF_INET6 &&
 634             ifa->ifa_flags & IFA_F_TENTATIVE)
 635                 addrs[ctxt->ret].tentative = true;
 636
 637         ctxt->ret++;
 638         *(ctxt->addrs) = addrs;
 639
 640         return NL_OK;
 641 }
 642
 643
 644 static int cb_addr_finish(_unused struct nl_msg *msg, void *arg)
 645 {
 646         struct addr_info *ctxt = (struct addr_info *)arg;
 647
 648         ctxt->pending = 0;
 649
 650         return NL_STOP;
 651 }
 652
 653
 654 static int cb_addr_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 655                 void *arg)
 656 {
 657         struct addr_info *ctxt = (struct addr_info *)arg;
 658
 659         ctxt->pending = 0;
 660         ctxt->ret = err->error;
 661
 662         return NL_STOP;
 663 }
 664
 665
 666 static int prefix_cmp(const void *va, const void *vb)
 667 {
 668         const struct odhcpd_ipaddr *a = va, *b = vb;
 669         int ret = 0;
 670
 671         if (a->prefix == b->prefix) {
 672                 ret = (ntohl(a->addr.in.s_addr) < ntohl(b->addr.in.s_addr)) ? 1 :
 673                         (ntohl(a->addr.in.s_addr) > ntohl(b->addr.in.s_addr)) ? -1 : 0;
 674         } else
 675                 ret = a->prefix < b->prefix ? 1 : -1;
 676
 677         return ret;
 678 }
 679
 680
 681 /* compare IPv6 prefixes */
 682 static int prefix6_cmp(const void *va, const void *vb)
 683 {
 684         const struct odhcpd_ipaddr *a = va, *b = vb;
 685         uint32_t a_pref = IN6_IS_ADDR_ULA(&a->addr.in6) ? 1 : a->preferred;
 686         uint32_t b_pref = IN6_IS_ADDR_ULA(&b->addr.in6) ? 1 : b->preferred;
 687         return (a_pref < b_pref) ? 1 : (a_pref > b_pref) ? -1 : 0;
 688 }
 689
 690
 691 /* Detect an IPV6-address currently assigned to the given interface */
 692 ssize_t netlink_get_interface_addrs(int ifindex, bool v6, struct odhcpd_ipaddr **addrs)
 693 {
 694         struct nl_msg *msg;
 695         struct ifaddrmsg ifa = {
 696                 .ifa_family = v6? AF_INET6: AF_INET,
 697                 .ifa_prefixlen = 0,
 698                 .ifa_flags = 0,
 699                 .ifa_scope = 0,
 700                 .ifa_index = ifindex, };
 701         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 702         struct addr_info ctxt = {
 703                 .ifindex = ifindex,
 704                 .af = v6? AF_INET6: AF_INET,
 705                 .addrs = addrs,
 706                 .ret = 0,
 707                 .pending = 1,
 708         };
 709
 710         if (!cb) {
 711                 ctxt.ret = -1;
 712                 goto out;
 713         }
 714
 715         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 716
 717         if (!msg) {
 718                 ctxt.ret = - 1;
 719                 goto out;
 720         }
 721
 722         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 723
 724         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_addr_valid, &ctxt);
 725         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_addr_finish, &ctxt);
 726         nl_cb_err(cb, NL_CB_CUSTOM, cb_addr_error, &ctxt);
 727
 728         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 729         if (ctxt.ret < 0)
 730                 goto free;
 731
 732         ctxt.ret = 0;
 733         while (ctxt.pending > 0)
 734                 nl_recvmsgs(rtnl_socket, cb);
 735
 736         if (ctxt.ret <= 0)
 737                 goto free;
 738
 739         time_t now = odhcpd_time();
 740         struct odhcpd_ipaddr *addr = *addrs;
 741
 742         qsort(addr, ctxt.ret, sizeof(*addr), v6 ? prefix6_cmp : prefix_cmp);
 743
 744         for (ssize_t i = 0; i < ctxt.ret; ++i) {
 745                 if (addr[i].preferred < UINT32_MAX - now)
 746                         addr[i].preferred += now;
 747
 748                 if (addr[i].valid < UINT32_MAX - now)
 749                         addr[i].valid += now;
 750         }
 751
 752 free:
 753         nlmsg_free(msg);
 754 out:
 755         nl_cb_put(cb);
 756
 757         return ctxt.ret;
 758 }
 759
 760
 761 struct neigh_info {
 762         int ifindex;
 763         int pending;
 764         const struct in6_addr *addr;
 765         int ret;
 766 };
 767
 768
 769 static int cb_proxy_neigh_valid(struct nl_msg *msg, void *arg)
 770 {
 771         struct neigh_info *ctxt = (struct neigh_info *)arg;
 772         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 773         struct ndmsg *ndm;
 774         struct nlattr *nla_dst;
 775
 776         if (hdr->nlmsg_type != RTM_NEWNEIGH)
 777                 return NL_SKIP;
 778
 779         ndm = NLMSG_DATA(hdr);
 780         if (ndm->ndm_family != AF_INET6 ||
 781                         (ctxt->ifindex && ndm->ndm_ifindex != ctxt->ifindex))
 782                 return NL_SKIP;
 783
 784         if (!(ndm->ndm_flags & NTF_PROXY))
 785                 return NL_SKIP;
 786
 787         nla_dst = nlmsg_find_attr(hdr, sizeof(*ndm), NDA_DST);
 788         if (!nla_dst)
 789                 return NL_SKIP;
 790
 791         if (nla_memcmp(nla_dst,ctxt->addr, 16) == 0)
 792                 ctxt->ret = 1;
 793
 794         return NL_OK;
 795 }
 796
 797
 798 static int cb_proxy_neigh_finish(_unused struct nl_msg *msg, void *arg)
 799 {
 800         struct neigh_info *ctxt = (struct neigh_info *)arg;
 801
 802         ctxt->pending = 0;
 803
 804         return NL_STOP;
 805 }
 806
 807
 808 static int cb_proxy_neigh_error(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 809                 void *arg)
 810 {
 811         struct neigh_info *ctxt = (struct neigh_info *)arg;
 812
 813         ctxt->pending = 0;
 814         ctxt->ret = err->error;
 815
 816         return NL_STOP;
 817 }
 818
 819 /* Detect an IPV6-address proxy neighbor for the given interface */
 820 int netlink_get_interface_proxy_neigh(int ifindex, const struct in6_addr *addr)
 821 {
 822         struct nl_msg *msg;
 823         struct ndmsg ndm = {
 824                 .ndm_family = AF_INET6,
 825                 .ndm_flags = NTF_PROXY,
 826                 .ndm_ifindex = ifindex,
 827         };
 828         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 829         struct neigh_info ctxt = {
 830                 .ifindex = ifindex,
 831                 .addr = addr,
 832                 .ret = 0,
 833                 .pending = 1,
 834         };
 835
 836         if (!cb) {
 837                 ctxt.ret = -1;
 838                 goto out;
 839         }
 840
 841         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_MATCH);
 842
 843         if (!msg) {
 844                 ctxt.ret = -1;
 845                 goto out;
 846         }
 847
 848         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 849         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 850
 851         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_proxy_neigh_valid, &ctxt);
 852         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_proxy_neigh_finish, &ctxt);
 853         nl_cb_err(cb, NL_CB_CUSTOM, cb_proxy_neigh_error, &ctxt);
 854
 855         ctxt.ret = nl_send_auto_complete(rtnl_socket, msg);
 856         if (ctxt.ret < 0)
 857                 goto free;
 858
 859         while (ctxt.pending > 0)
 860                 nl_recvmsgs(rtnl_socket, cb);
 861
 862 free:
 863         nlmsg_free(msg);
 864 out:
 865         nl_cb_put(cb);
 866
 867         return ctxt.ret;
 868 }
 869
 870
 871 int netlink_setup_route(const struct in6_addr *addr, const int prefixlen,
 872                 const int ifindex, const struct in6_addr *gw,
 873                 const uint32_t metric, const bool add)
 874 {
 875         struct nl_msg *msg;
 876         struct rtmsg rtm = {
 877                 .rtm_family = AF_INET6,
 878                 .rtm_dst_len = prefixlen,
 879                 .rtm_src_len = 0,
 880                 .rtm_table = RT_TABLE_MAIN,
 881                 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
 882                 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
 883                 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
 884         };
 885         int ret = 0;
 886
 887         msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
 888                                         add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
 889         if (!msg)
 890                 return -1;
 891
 892         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 893
 894         nla_put(msg, RTA_DST, sizeof(*addr), addr);
 895         nla_put_u32(msg, RTA_OIF, ifindex);
 896         nla_put_u32(msg, RTA_PRIORITY, metric);
 897
 898         if (gw)
 899                 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
 900
 901         ret = nl_send_auto_complete(rtnl_socket, msg);
 902         nlmsg_free(msg);
 903
 904         if (ret < 0)
 905                 return ret;
 906
 907         return nl_wait_for_ack(rtnl_socket);
 908 }
 909
 910
 911 int netlink_setup_proxy_neigh(const struct in6_addr *addr,
 912                 const int ifindex, const bool add)
 913 {
 914         struct nl_msg *msg;
 915         struct ndmsg ndm = {
 916                 .ndm_family = AF_INET6,
 917                 .ndm_flags = NTF_PROXY,
 918                 .ndm_ifindex = ifindex,
 919         };
 920         int ret = 0, flags = NLM_F_REQUEST;
 921
 922         if (add)
 923                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 924
 925         msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
 926         if (!msg)
 927                 return -1;
 928
 929         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 930
 931         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 932
 933         ret = nl_send_auto_complete(rtnl_socket, msg);
 934         nlmsg_free(msg);
 935
 936         if (ret < 0)
 937                 return ret;
 938
 939         return nl_wait_for_ack(rtnl_socket);
 940 }
 941
 942
 943 int netlink_setup_addr(struct odhcpd_ipaddr *addr,
 944                 const int ifindex, const bool v6, const bool add)
 945 {
 946         struct nl_msg *msg;
 947         struct ifaddrmsg ifa = {
 948                 .ifa_family = v6 ? AF_INET6 : AF_INET,
 949                 .ifa_prefixlen = addr->prefix,
 950                 .ifa_flags = 0,
 951                 .ifa_scope = 0,
 952                 .ifa_index = ifindex, };
 953         int ret = 0, flags = NLM_F_REQUEST;
 954
 955         if (add)
 956                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 957
 958         msg = nlmsg_alloc_simple(add ? RTM_NEWADDR : RTM_DELADDR, 0);
 959         if (!msg)
 960                 return -1;
 961
 962         nlmsg_append(msg, &ifa, sizeof(ifa), flags);
 963         nla_put(msg, IFA_LOCAL, v6 ? 16 : 4, &addr->addr);
 964         if (v6) {
 965                 struct ifa_cacheinfo cinfo = {  .ifa_prefered = 0xffffffffU,
 966                                                 .ifa_valid = 0xffffffffU,
 967                                                 .cstamp = 0,
 968                                                 .tstamp = 0 };
 969                 time_t now = odhcpd_time();
 970
 971                 if (addr->preferred) {
 972                         int64_t preferred = addr->preferred - now;
 973                         if (preferred < 0)
 974                                 preferred = 0;
 975                         else if (preferred > UINT32_MAX)
 976                                 preferred = UINT32_MAX;
 977
 978                         cinfo.ifa_prefered = preferred;
 979                 }
 980
 981                 if (addr->valid) {
 982                         int64_t valid = addr->valid - now;
 983                         if (valid <= 0) {
 984                                 nlmsg_free(msg);
 985                                 return -1;
 986                         }
 987                         else if (valid > UINT32_MAX)
 988                                 valid = UINT32_MAX;
 989
 990                         cinfo.ifa_valid = valid;
 991                 }
 992
 993                 nla_put(msg, IFA_CACHEINFO, sizeof(cinfo), &cinfo);
 994
 995                 nla_put_u32(msg, IFA_FLAGS, IFA_F_NOPREFIXROUTE);
 996         } else {
 997                 if (addr->broadcast.s_addr)
 998                         nla_put_u32(msg, IFA_BROADCAST, addr->broadcast.s_addr);
 999         }
1000
1001         ret = nl_send_auto_complete(rtnl_socket, msg);
1002         nlmsg_free(msg);
1003
1004         if (ret < 0)
1005                 return ret;
1006
1007         return nl_wait_for_ack(rtnl_socket);
1008 }
1009
1010 void netlink_dump_neigh_table(const bool proxy)
1011 {
1012         struct nl_msg *msg;
1013         struct ndmsg ndm = {
1014                 .ndm_family = AF_INET6,
1015                 .ndm_flags = proxy ? NTF_PROXY : 0,
1016         };
1017
1018         msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_DUMP);
1019         if (!msg)
1020                 return;
1021
1022         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
1023
1024         nl_send_auto_complete(rtnl_event.sock, msg);
1025
1026         nlmsg_free(msg);
1027 }
1028
1029 void netlink_dump_addr_table(const bool v6)
1030 {
1031         struct nl_msg *msg;
1032         struct ifaddrmsg ifa = {
1033                 .ifa_family = v6 ? AF_INET6 : AF_INET,
1034         };
1035
1036         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
1037         if (!msg)
1038                 return;
1039
1040         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
1041
1042         nl_send_auto_complete(rtnl_event.sock, msg);
1043
1044         nlmsg_free(msg);
1045 }