src/odhcpd.c

   1 /**
   2  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
   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 <time.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <stdio.h>
  19 #include <resolv.h>
  20 #include <getopt.h>
  21 #include <stddef.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <signal.h>
  26 #include <stdbool.h>
  27 #include <syslog.h>
  28
  29 #include <arpa/inet.h>
  30 #include <net/if.h>
  31 #include <netinet/ip6.h>
  32 #include <netpacket/packet.h>
  33 #include <linux/netlink.h>
  34 #include <linux/if_addr.h>
  35 #include <linux/neighbour.h>
  36 #include <linux/rtnetlink.h>
  37
  38 #include <sys/socket.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/epoll.h>
  41 #include <sys/types.h>
  42 #include <sys/wait.h>
  43 #include <sys/syscall.h>
  44
  45 #include <netlink/msg.h>
  46 #include <netlink/socket.h>
  47 #include <netlink/attr.h>
  48 #include <libubox/uloop.h>
  49 #include "odhcpd.h"
  50
  51
  52
  53 static int ioctl_sock;
  54 static struct nl_sock *rtnl_socket = NULL;
  55 static int urandom_fd = -1;
  56
  57 static void sighandler(_unused int signal)
  58 {
  59         uloop_end();
  60 }
  61
  62 static void print_usage(const char *app)
  63 {
  64         printf(
  65         "== %s Usage ==\n\n"
  66         "  -h, --help   Print this help\n"
  67         "  -l level     Specify log level 0..7 (default %d)\n",
  68                 app, config.log_level
  69         );
  70 }
  71
  72 int main(int argc, char **argv)
  73 {
  74         openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
  75         int opt;
  76
  77         while ((opt = getopt(argc, argv, "hl:")) != -1) {
  78                 switch (opt) {
  79                 case 'h':
  80                         print_usage(argv[0]);
  81                         return 0;
  82                 case 'l':
  83                         config.log_level = (atoi(optarg) & LOG_PRIMASK);
  84                         fprintf(stderr, "Log level set to %d\n", config.log_level);
  85                         break;
  86                 }
  87         }
  88         setlogmask(LOG_UPTO(config.log_level));
  89         uloop_init();
  90
  91         if (getuid() != 0) {
  92                 syslog(LOG_ERR, "Must be run as root!");
  93                 return 2;
  94         }
  95
  96         ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
  97
  98         if (!(rtnl_socket = odhcpd_create_nl_socket(NETLINK_ROUTE))) {
  99                 syslog(LOG_ERR, "Unable to open nl socket: %s", strerror(errno));
 100                 return 2;
 101         }
 102
 103         if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
 104                 return 4;
 105
 106         signal(SIGUSR1, SIG_IGN);
 107         signal(SIGINT, sighandler);
 108         signal(SIGTERM, sighandler);
 109
 110         if (init_router())
 111                 return 4;
 112
 113         if (init_dhcpv6())
 114                 return 4;
 115
 116         if (init_ndp())
 117                 return 4;
 118
 119 #ifdef DHCPV4_SUPPORT
 120         if (init_dhcpv4())
 121                 return 4;
 122 #endif
 123
 124         odhcpd_run();
 125         return 0;
 126 }
 127
 128 struct nl_sock *odhcpd_create_nl_socket(int protocol)
 129 {
 130         struct nl_sock *nl_sock;
 131
 132         nl_sock = nl_socket_alloc();
 133         if (!nl_sock)
 134                 goto err;
 135
 136         if (nl_connect(nl_sock, protocol) < 0)
 137                 goto err;
 138
 139         return nl_sock;
 140
 141 err:
 142         if (nl_sock)
 143                 nl_socket_free(nl_sock);
 144
 145         return NULL;
 146 }
 147
 148
 149 // Read IPv6 MTU for interface
 150 int odhcpd_get_interface_config(const char *ifname, const char *what)
 151 {
 152         char buf[64];
 153         const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
 154         snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
 155
 156         int fd = open(buf, O_RDONLY);
 157         ssize_t len = read(fd, buf, sizeof(buf) - 1);
 158         close(fd);
 159
 160         if (len < 0)
 161                 return -1;
 162
 163         buf[len] = 0;
 164         return atoi(buf);
 165 }
 166
 167
 168 // Read IPv6 MAC for interface
 169 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
 170 {
 171         struct ifreq ifr;
 172         memset(&ifr, 0, sizeof(ifr));
 173         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
 174         if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
 175                 return -1;
 176         memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
 177         return 0;
 178 }
 179
 180
 181 // Forwards a packet on a specific interface
 182 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 183                 struct iovec *iov, size_t iov_len,
 184                 const struct interface *iface)
 185 {
 186         // Construct headers
 187         uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
 188         struct msghdr msg = {
 189                 .msg_name = (void *) dest,
 190                 .msg_namelen = sizeof(*dest),
 191                 .msg_iov = iov,
 192                 .msg_iovlen = iov_len,
 193                 .msg_control = cmsg_buf,
 194                 .msg_controllen = sizeof(cmsg_buf),
 195                 .msg_flags = 0
 196         };
 197
 198         // Set control data (define destination interface)
 199         struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
 200         chdr->cmsg_level = IPPROTO_IPV6;
 201         chdr->cmsg_type = IPV6_PKTINFO;
 202         chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
 203         struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
 204         pktinfo->ipi6_ifindex = iface->ifindex;
 205
 206         // Also set scope ID if link-local
 207         if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
 208                         || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
 209                 dest->sin6_scope_id = iface->ifindex;
 210
 211         char ipbuf[INET6_ADDRSTRLEN];
 212         inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
 213
 214         ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
 215         if (sent < 0)
 216                 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%s)",
 217                                 ipbuf, iface->ifname, strerror(errno));
 218         else
 219                 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
 220                                 (long)sent, ipbuf, iface->ifname);
 221         return sent;
 222 }
 223
 224 struct addr_info {
 225         int ifindex;
 226         struct odhcpd_ipaddr *addrs;
 227         size_t addrs_sz;
 228         int pending;
 229         ssize_t ret;
 230 };
 231
 232 static int cb_valid_handler(struct nl_msg *msg, void *arg)
 233 {
 234         struct addr_info *ctxt = (struct addr_info *)arg;
 235         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 236         struct ifaddrmsg *ifa;
 237         struct nlattr *nla[__IFA_MAX];
 238
 239         if (hdr->nlmsg_type != RTM_NEWADDR || ctxt->ret >= (ssize_t)ctxt->addrs_sz)
 240                 return NL_SKIP;
 241
 242         ifa = NLMSG_DATA(hdr);
 243         if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
 244                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 245                 return NL_SKIP;
 246
 247         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 248         if (!nla[IFA_ADDRESS])
 249                 return NL_SKIP;
 250
 251         memset(&ctxt->addrs[ctxt->ret], 0, sizeof(ctxt->addrs[ctxt->ret]));
 252         ctxt->addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 253
 254         nla_memcpy(&ctxt->addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
 255                         sizeof(ctxt->addrs[ctxt->ret].addr));
 256
 257         if (nla[IFA_CACHEINFO]) {
 258                 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 259
 260                 ctxt->addrs[ctxt->ret].preferred = ifc->ifa_prefered;
 261                 ctxt->addrs[ctxt->ret].valid = ifc->ifa_valid;
 262         }
 263
 264         if (ifa->ifa_flags & IFA_F_DEPRECATED)
 265                 ctxt->addrs[ctxt->ret].preferred = 0;
 266
 267         ctxt->ret++;
 268
 269         return NL_OK;
 270 }
 271
 272 static int cb_finish_handler(_unused struct nl_msg *msg, void *arg)
 273 {
 274         struct addr_info *ctxt = (struct addr_info *)arg;
 275
 276         ctxt->pending = 0;
 277
 278         return NL_STOP;
 279 }
 280
 281 static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 282                 void *arg)
 283 {
 284         struct addr_info *ctxt = (struct addr_info *)arg;
 285
 286         ctxt->pending = 0;
 287         ctxt->ret = err->error;
 288
 289         return NL_STOP;
 290 }
 291
 292 // Detect an IPV6-address currently assigned to the given interface
 293 ssize_t odhcpd_get_interface_addresses(int ifindex,
 294                 struct odhcpd_ipaddr *addrs, size_t cnt)
 295 {
 296         struct nl_msg *msg;
 297         struct ifaddrmsg ifa = {
 298                 .ifa_family = AF_INET6,
 299                 .ifa_prefixlen = 0,
 300                 .ifa_flags = 0,
 301                 .ifa_scope = 0,
 302                 .ifa_index = ifindex, };
 303         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 304         struct addr_info ctxt = {
 305                 .ifindex = ifindex,
 306                 .addrs = addrs,
 307                 .addrs_sz = cnt,
 308                 .ret = 0,
 309                 .pending = 1,
 310         };
 311
 312         if (!cb) {
 313                 ctxt.ret = -1;
 314                 goto out;
 315         }
 316
 317         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 318
 319         if (!msg) {
 320                 ctxt.ret = - 1;
 321                 goto out;
 322         }
 323
 324         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 325
 326         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_valid_handler, &ctxt);
 327         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_finish_handler, &ctxt);
 328         nl_cb_err(cb, NL_CB_CUSTOM, cb_error_handler, &ctxt);
 329
 330         nl_send_auto_complete(rtnl_socket, msg);
 331         while (ctxt.pending > 0)
 332                 nl_recvmsgs(rtnl_socket, cb);
 333
 334         nlmsg_free(msg);
 335 out:
 336         nl_cb_put(cb);
 337
 338         return ctxt.ret;
 339 }
 340
 341 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
 342 {
 343         int status = -1;
 344         struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
 345         socklen_t alen = sizeof(addr);
 346         int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
 347
 348         if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
 349                         !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
 350                 *lladdr = addr.sin6_addr;
 351                 status = 0;
 352         }
 353
 354         close(sock);
 355
 356         return status;
 357 }
 358
 359 /*
 360  * DNS address selection criteria order :
 361  * - use IPv6 address with valid lifetime if none is yet selected
 362  * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
 363  * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
 364  * - use the IPv6 address with the longest preferred lifetime
 365  */
 366 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
 367 {
 368         time_t now = odhcpd_time();
 369         ssize_t m = -1;
 370
 371         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 372                 if (iface->ia_addr[i].valid <= (uint32_t)now)
 373                         continue;
 374
 375                 if (m < 0) {
 376                         m = i;
 377                         continue;
 378                 }
 379
 380                 if (iface->ia_addr[m].preferred >= (uint32_t)now &&
 381                                 iface->ia_addr[i].preferred < (uint32_t)now)
 382                         continue;
 383
 384                 if (IN6_IS_ADDR_ULA(&iface->ia_addr[i].addr)) {
 385                         if (!IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr)) {
 386                                 m = i;
 387                                 continue;
 388                         }
 389                 } else if (IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr))
 390                         continue;
 391
 392                 if (iface->ia_addr[i].preferred > iface->ia_addr[m].preferred)
 393                         m = i;
 394         }
 395
 396         if (m >= 0) {
 397                 *addr = iface->ia_addr[m].addr;
 398                 return 0;
 399         }
 400
 401         return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
 402 }
 403
 404 int odhcpd_setup_route(const struct in6_addr *addr, const int prefixlen,
 405                 const struct interface *iface, const struct in6_addr *gw,
 406                 const uint32_t metric, const bool add)
 407 {
 408         struct nl_msg *msg;
 409         struct rtmsg rtm = {
 410                 .rtm_family = AF_INET6,
 411                 .rtm_dst_len = prefixlen,
 412                 .rtm_src_len = 0,
 413                 .rtm_table = RT_TABLE_MAIN,
 414                 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
 415                 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
 416                 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
 417         };
 418         int ret = 0;
 419
 420         msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
 421                                         add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
 422         if (!msg)
 423                 return -1;
 424
 425         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 426
 427         nla_put(msg, RTA_DST, sizeof(*addr), addr);
 428         nla_put_u32(msg, RTA_OIF, iface->ifindex);
 429         nla_put_u32(msg, RTA_PRIORITY, metric);
 430
 431         if (gw)
 432                 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
 433
 434         ret = nl_send_auto_complete(rtnl_socket, msg);
 435         nlmsg_free(msg);
 436
 437         if (ret < 0)
 438                 return ret;
 439
 440         return nl_wait_for_ack(rtnl_socket);
 441 }
 442
 443 int odhcpd_setup_proxy_neigh(const struct in6_addr *addr,
 444                 const struct interface *iface, const bool add)
 445 {
 446         struct nl_msg *msg;
 447         struct ndmsg ndm = {
 448                 .ndm_family = AF_INET6,
 449                 .ndm_flags = NTF_PROXY,
 450                 .ndm_ifindex = iface->ifindex,
 451         };
 452         int ret = 0, flags = NLM_F_REQUEST;
 453
 454         if (add)
 455                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 456
 457         msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
 458         if (!msg)
 459                 return -1;
 460
 461         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 462
 463         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 464
 465         ret = nl_send_auto_complete(rtnl_socket, msg);
 466         nlmsg_free(msg);
 467
 468         if (ret < 0)
 469                 return ret;
 470
 471         return nl_wait_for_ack(rtnl_socket);
 472 }
 473
 474 struct interface* odhcpd_get_interface_by_index(int ifindex)
 475 {
 476         struct interface *iface;
 477         list_for_each_entry(iface, &interfaces, head)
 478                 if (iface->ifindex == ifindex)
 479                         return iface;
 480
 481         return NULL;
 482 }
 483
 484
 485 struct interface* odhcpd_get_interface_by_name(const char *name)
 486 {
 487         struct interface *iface;
 488         list_for_each_entry(iface, &interfaces, head)
 489                 if (!strcmp(iface->ifname, name))
 490                         return iface;
 491
 492         return NULL;
 493 }
 494
 495
 496 struct interface* odhcpd_get_master_interface(void)
 497 {
 498         struct interface *iface;
 499         list_for_each_entry(iface, &interfaces, head)
 500                 if (iface->master)
 501                         return iface;
 502
 503         return NULL;
 504 }
 505
 506
 507 // Convenience function to receive and do basic validation of packets
 508 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
 509 {
 510         struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
 511
 512         uint8_t data_buf[RELAYD_BUFFER_SIZE], cmsg_buf[128];
 513         union {
 514                 struct sockaddr_in6 in6;
 515                 struct sockaddr_in in;
 516                 struct sockaddr_ll ll;
 517                 struct sockaddr_nl nl;
 518         } addr;
 519
 520         if (u->error) {
 521                 int ret = -1;
 522                 socklen_t ret_len = sizeof(ret);
 523                 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
 524                 u->error = false;
 525                 if (e->handle_error)
 526                         e->handle_error(e, ret);
 527         }
 528
 529         if (e->recv_msgs) {
 530                 e->recv_msgs(e);
 531                 return;
 532         }
 533
 534         while (true) {
 535                 struct iovec iov = {data_buf, sizeof(data_buf)};
 536                 struct msghdr msg = {
 537                         .msg_name = (void *) &addr,
 538                         .msg_namelen = sizeof(addr),
 539                         .msg_iov = &iov,
 540                         .msg_iovlen = 1,
 541                         .msg_control = cmsg_buf,
 542                         .msg_controllen = sizeof(cmsg_buf),
 543                         .msg_flags = 0
 544                 };
 545
 546                 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
 547                 if (len < 0) {
 548                         if (errno == EAGAIN)
 549                                 break;
 550                         else
 551                                 continue;
 552                 }
 553
 554
 555                 // Extract destination interface
 556                 int destiface = 0;
 557                 int *hlim = NULL;
 558                 void *dest = NULL;
 559                 struct in6_pktinfo *pktinfo;
 560                 struct in_pktinfo *pkt4info;
 561                 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
 562                         if (ch->cmsg_level == IPPROTO_IPV6 &&
 563                                         ch->cmsg_type == IPV6_PKTINFO) {
 564                                 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
 565                                 destiface = pktinfo->ipi6_ifindex;
 566                                 dest = &pktinfo->ipi6_addr;
 567                         } else if (ch->cmsg_level == IPPROTO_IP &&
 568                                         ch->cmsg_type == IP_PKTINFO) {
 569                                 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
 570                                 destiface = pkt4info->ipi_ifindex;
 571                                 dest = &pkt4info->ipi_addr;
 572                         } else if (ch->cmsg_level == IPPROTO_IPV6 &&
 573                                         ch->cmsg_type == IPV6_HOPLIMIT) {
 574                                 hlim = (int*)CMSG_DATA(ch);
 575                         }
 576                 }
 577
 578                 // Check hoplimit if received
 579                 if (hlim && *hlim != 255)
 580                         continue;
 581
 582                 // Detect interface for packet sockets
 583                 if (addr.ll.sll_family == AF_PACKET)
 584                         destiface = addr.ll.sll_ifindex;
 585
 586                 struct interface *iface =
 587                                 odhcpd_get_interface_by_index(destiface);
 588
 589                 if (!iface && addr.nl.nl_family != AF_NETLINK)
 590                         continue;
 591
 592                 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
 593                 if (addr.ll.sll_family == AF_PACKET &&
 594                                 len >= (ssize_t)sizeof(struct ip6_hdr))
 595                         inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
 596                 else if (addr.in6.sin6_family == AF_INET6)
 597                         inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
 598                 else if (addr.in.sin_family == AF_INET)
 599                         inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
 600
 601                 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
 602                                 ipbuf, (iface) ? iface->ifname : "netlink");
 603
 604                 e->handle_dgram(&addr, data_buf, len, iface, dest);
 605         }
 606 }
 607
 608 // Register events for the multiplexer
 609 int odhcpd_register(struct odhcpd_event *event)
 610 {
 611         event->uloop.cb = odhcpd_receive_packets;
 612         return uloop_fd_add(&event->uloop, ULOOP_READ |
 613                         ((event->handle_error) ? ULOOP_ERROR_CB : 0));
 614 }
 615
 616 int odhcpd_deregister(struct odhcpd_event *event)
 617 {
 618         event->uloop.cb = NULL;
 619         return uloop_fd_delete(&event->uloop);
 620 }
 621
 622 void odhcpd_process(struct odhcpd_event *event)
 623 {
 624         odhcpd_receive_packets(&event->uloop, 0);
 625 }
 626
 627 int odhcpd_urandom(void *data, size_t len)
 628 {
 629         return read(urandom_fd, data, len);
 630 }
 631
 632
 633 time_t odhcpd_time(void)
 634 {
 635         struct timespec ts;
 636         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
 637         return ts.tv_sec;
 638 }
 639
 640
 641 static const char hexdigits[] = "0123456789abcdef";
 642 static const int8_t hexvals[] = {
 643     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
 644     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 645     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 646      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
 647     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 648     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 649     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 650     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 651 };
 652
 653 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
 654 {
 655         size_t c;
 656         for (c = 0; c < len && src[0] && src[1]; ++c) {
 657                 int8_t x = (int8_t)*src++;
 658                 int8_t y = (int8_t)*src++;
 659                 if (x < 0 || (x = hexvals[x]) < 0
 660                                 || y < 0 || (y = hexvals[y]) < 0)
 661                         return -1;
 662                 dst[c] = x << 4 | y;
 663                 while (((int8_t)*src) < 0 ||
 664                                 (*src && hexvals[(uint8_t)*src] < 0))
 665                         src++;
 666         }
 667
 668         return c;
 669 }
 670
 671
 672 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
 673 {
 674         for (size_t i = 0; i < len; ++i) {
 675                 *dst++ = hexdigits[src[i] >> 4];
 676                 *dst++ = hexdigits[src[i] & 0x0f];
 677         }
 678         *dst = 0;
 679 }
 680
 681
 682 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
 683 {
 684         const uint8_t *a = av, *b = bv;
 685         size_t bytes = bits / 8;
 686         bits %= 8;
 687
 688         int res = memcmp(a, b, bytes);
 689         if (res == 0 && bits > 0)
 690                 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
 691
 692         return res;
 693 }
 694
 695
 696 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
 697 {
 698         uint8_t *a = av;
 699         const uint8_t *b = bv;
 700
 701         size_t bytes = bits / 8;
 702         bits %= 8;
 703         memcpy(a, b, bytes);
 704
 705         if (bits > 0) {
 706                 uint8_t mask = (1 << (8 - bits)) - 1;
 707                 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
 708         }
 709 }