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 #include <alloca.h>
  29
  30 #include <arpa/inet.h>
  31 #include <net/if.h>
  32 #include <netinet/ip6.h>
  33 #include <netpacket/packet.h>
  34 #include <linux/netlink.h>
  35 #include <linux/if_addr.h>
  36 #include <linux/neighbour.h>
  37 #include <linux/rtnetlink.h>
  38
  39 #include <sys/socket.h>
  40 #include <sys/ioctl.h>
  41 #include <sys/epoll.h>
  42 #include <sys/types.h>
  43 #include <sys/wait.h>
  44 #include <sys/syscall.h>
  45
  46 #include <netlink/msg.h>
  47 #include <netlink/socket.h>
  48 #include <netlink/attr.h>
  49 #include <libubox/uloop.h>
  50 #include "odhcpd.h"
  51
  52
  53
  54 static int ioctl_sock;
  55 static struct nl_sock *rtnl_socket = NULL;
  56 static int urandom_fd = -1;
  57
  58 static void sighandler(_unused int signal)
  59 {
  60         uloop_end();
  61 }
  62
  63 static void print_usage(const char *app)
  64 {
  65         printf(
  66         "== %s Usage ==\n\n"
  67         "  -h, --help   Print this help\n"
  68         "  -l level     Specify log level 0..7 (default %d)\n",
  69                 app, config.log_level
  70         );
  71 }
  72
  73 int main(int argc, char **argv)
  74 {
  75         openlog("odhcpd", LOG_PERROR | LOG_PID, LOG_DAEMON);
  76         int opt;
  77
  78         while ((opt = getopt(argc, argv, "hl:")) != -1) {
  79                 switch (opt) {
  80                 case 'h':
  81                         print_usage(argv[0]);
  82                         return 0;
  83                 case 'l':
  84                         config.log_level = (atoi(optarg) & LOG_PRIMASK);
  85                         fprintf(stderr, "Log level set to %d\n", config.log_level);
  86                         break;
  87                 }
  88         }
  89         setlogmask(LOG_UPTO(config.log_level));
  90         uloop_init();
  91
  92         if (getuid() != 0) {
  93                 syslog(LOG_ERR, "Must be run as root!");
  94                 return 2;
  95         }
  96
  97         ioctl_sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
  98
  99         if (!(rtnl_socket = odhcpd_create_nl_socket(NETLINK_ROUTE))) {
 100                 syslog(LOG_ERR, "Unable to open nl socket: %s", strerror(errno));
 101                 return 2;
 102         }
 103
 104         if ((urandom_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC)) < 0)
 105                 return 4;
 106
 107         signal(SIGUSR1, SIG_IGN);
 108         signal(SIGINT, sighandler);
 109         signal(SIGTERM, sighandler);
 110
 111         if (init_router())
 112                 return 4;
 113
 114         if (init_dhcpv6())
 115                 return 4;
 116
 117         if (init_ndp())
 118                 return 4;
 119
 120         if (init_dhcpv4())
 121                 return 4;
 122
 123         odhcpd_run();
 124         return 0;
 125 }
 126
 127 struct nl_sock *odhcpd_create_nl_socket(int protocol)
 128 {
 129         struct nl_sock *nl_sock;
 130
 131         nl_sock = nl_socket_alloc();
 132         if (!nl_sock)
 133                 goto err;
 134
 135         if (nl_connect(nl_sock, protocol) < 0)
 136                 goto err;
 137
 138         return nl_sock;
 139
 140 err:
 141         if (nl_sock)
 142                 nl_socket_free(nl_sock);
 143
 144         return NULL;
 145 }
 146
 147
 148 // Read IPv6 MTU for interface
 149 int odhcpd_get_interface_config(const char *ifname, const char *what)
 150 {
 151         char buf[64];
 152         const char *sysctl_pattern = "/proc/sys/net/ipv6/conf/%s/%s";
 153         snprintf(buf, sizeof(buf), sysctl_pattern, ifname, what);
 154
 155         int fd = open(buf, O_RDONLY);
 156         ssize_t len = read(fd, buf, sizeof(buf) - 1);
 157         close(fd);
 158
 159         if (len < 0)
 160                 return -1;
 161
 162         buf[len] = 0;
 163         return atoi(buf);
 164 }
 165
 166
 167 // Read IPv6 MAC for interface
 168 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
 169 {
 170         struct ifreq ifr;
 171         memset(&ifr, 0, sizeof(ifr));
 172         strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
 173         if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
 174                 return -1;
 175         memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
 176         return 0;
 177 }
 178
 179
 180 // Forwards a packet on a specific interface
 181 ssize_t odhcpd_send(int socket, struct sockaddr_in6 *dest,
 182                 struct iovec *iov, size_t iov_len,
 183                 const struct interface *iface)
 184 {
 185         // Construct headers
 186         uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))] = {0};
 187         struct msghdr msg = {
 188                 .msg_name = (void *) dest,
 189                 .msg_namelen = sizeof(*dest),
 190                 .msg_iov = iov,
 191                 .msg_iovlen = iov_len,
 192                 .msg_control = cmsg_buf,
 193                 .msg_controllen = sizeof(cmsg_buf),
 194                 .msg_flags = 0
 195         };
 196
 197         // Set control data (define destination interface)
 198         struct cmsghdr *chdr = CMSG_FIRSTHDR(&msg);
 199         chdr->cmsg_level = IPPROTO_IPV6;
 200         chdr->cmsg_type = IPV6_PKTINFO;
 201         chdr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
 202         struct in6_pktinfo *pktinfo = (struct in6_pktinfo*)CMSG_DATA(chdr);
 203         pktinfo->ipi6_ifindex = iface->ifindex;
 204
 205         // Also set scope ID if link-local
 206         if (IN6_IS_ADDR_LINKLOCAL(&dest->sin6_addr)
 207                         || IN6_IS_ADDR_MC_LINKLOCAL(&dest->sin6_addr))
 208                 dest->sin6_scope_id = iface->ifindex;
 209
 210         char ipbuf[INET6_ADDRSTRLEN];
 211         inet_ntop(AF_INET6, &dest->sin6_addr, ipbuf, sizeof(ipbuf));
 212
 213         ssize_t sent = sendmsg(socket, &msg, MSG_DONTWAIT);
 214         if (sent < 0)
 215                 syslog(LOG_NOTICE, "Failed to send to %s%%%s (%s)",
 216                                 ipbuf, iface->ifname, strerror(errno));
 217         else
 218                 syslog(LOG_DEBUG, "Sent %li bytes to %s%%%s",
 219                                 (long)sent, ipbuf, iface->ifname);
 220         return sent;
 221 }
 222
 223 struct addr_info {
 224         int ifindex;
 225         struct odhcpd_ipaddr **addrs;
 226         int pending;
 227         ssize_t ret;
 228 };
 229
 230 static int cb_valid_handler(struct nl_msg *msg, void *arg)
 231 {
 232         struct addr_info *ctxt = (struct addr_info *)arg;
 233         struct odhcpd_ipaddr *addrs = *(ctxt->addrs);
 234         struct nlmsghdr *hdr = nlmsg_hdr(msg);
 235         struct ifaddrmsg *ifa;
 236         struct nlattr *nla[__IFA_MAX];
 237
 238         if (hdr->nlmsg_type != RTM_NEWADDR)
 239                 return NL_SKIP;
 240
 241         ifa = NLMSG_DATA(hdr);
 242         if (ifa->ifa_scope != RT_SCOPE_UNIVERSE ||
 243                         (ctxt->ifindex && ifa->ifa_index != (unsigned)ctxt->ifindex))
 244                 return NL_SKIP;
 245
 246         nlmsg_parse(hdr, sizeof(*ifa), nla, __IFA_MAX - 1, NULL);
 247         if (!nla[IFA_ADDRESS])
 248                 return NL_SKIP;
 249
 250         addrs = realloc(addrs, sizeof(*addrs)*(ctxt->ret + 1));
 251         if (!addrs)
 252                 return NL_SKIP;
 253
 254         memset(&addrs[ctxt->ret], 0, sizeof(addrs[ctxt->ret]));
 255         addrs[ctxt->ret].prefix = ifa->ifa_prefixlen;
 256
 257         nla_memcpy(&addrs[ctxt->ret].addr, nla[IFA_ADDRESS],
 258                         sizeof(addrs[ctxt->ret].addr));
 259
 260         if (nla[IFA_CACHEINFO]) {
 261                 struct ifa_cacheinfo *ifc = nla_data(nla[IFA_CACHEINFO]);
 262
 263                 addrs[ctxt->ret].preferred = ifc->ifa_prefered;
 264                 addrs[ctxt->ret].valid = ifc->ifa_valid;
 265         }
 266
 267         if (ifa->ifa_flags & IFA_F_DEPRECATED)
 268                 addrs[ctxt->ret].preferred = 0;
 269
 270         ctxt->ret++;
 271         *(ctxt->addrs) = addrs;
 272
 273         return NL_OK;
 274 }
 275
 276 static int cb_finish_handler(_unused struct nl_msg *msg, void *arg)
 277 {
 278         struct addr_info *ctxt = (struct addr_info *)arg;
 279
 280         ctxt->pending = 0;
 281
 282         return NL_STOP;
 283 }
 284
 285 static int cb_error_handler(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
 286                 void *arg)
 287 {
 288         struct addr_info *ctxt = (struct addr_info *)arg;
 289
 290         ctxt->pending = 0;
 291         ctxt->ret = err->error;
 292
 293         return NL_STOP;
 294 }
 295
 296 // Detect an IPV6-address currently assigned to the given interface
 297 ssize_t odhcpd_get_interface_addresses(int ifindex, struct odhcpd_ipaddr **addrs)
 298 {
 299         struct nl_msg *msg;
 300         struct ifaddrmsg ifa = {
 301                 .ifa_family = AF_INET6,
 302                 .ifa_prefixlen = 0,
 303                 .ifa_flags = 0,
 304                 .ifa_scope = 0,
 305                 .ifa_index = ifindex, };
 306         struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
 307         struct addr_info ctxt = {
 308                 .ifindex = ifindex,
 309                 .addrs = addrs,
 310                 .ret = 0,
 311                 .pending = 1,
 312         };
 313
 314         if (!cb) {
 315                 ctxt.ret = -1;
 316                 goto out;
 317         }
 318
 319         msg = nlmsg_alloc_simple(RTM_GETADDR, NLM_F_REQUEST | NLM_F_DUMP);
 320
 321         if (!msg) {
 322                 ctxt.ret = - 1;
 323                 goto out;
 324         }
 325
 326         nlmsg_append(msg, &ifa, sizeof(ifa), 0);
 327
 328         nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_valid_handler, &ctxt);
 329         nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_finish_handler, &ctxt);
 330         nl_cb_err(cb, NL_CB_CUSTOM, cb_error_handler, &ctxt);
 331
 332         nl_send_auto_complete(rtnl_socket, msg);
 333         while (ctxt.pending > 0)
 334                 nl_recvmsgs(rtnl_socket, cb);
 335
 336         nlmsg_free(msg);
 337 out:
 338         nl_cb_put(cb);
 339
 340         return ctxt.ret;
 341 }
 342
 343 static int odhcpd_get_linklocal_interface_address(int ifindex, struct in6_addr *lladdr)
 344 {
 345         int status = -1;
 346         struct sockaddr_in6 addr = {AF_INET6, 0, 0, ALL_IPV6_ROUTERS, ifindex};
 347         socklen_t alen = sizeof(addr);
 348         int sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6);
 349
 350         if (!connect(sock, (struct sockaddr*)&addr, sizeof(addr)) &&
 351                         !getsockname(sock, (struct sockaddr*)&addr, &alen)) {
 352                 *lladdr = addr.sin6_addr;
 353                 status = 0;
 354         }
 355
 356         close(sock);
 357
 358         return status;
 359 }
 360
 361 /*
 362  * DNS address selection criteria order :
 363  * - use IPv6 address with valid lifetime if none is yet selected
 364  * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
 365  * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
 366  * - use the IPv6 address with the longest preferred lifetime
 367  */
 368 int odhcpd_get_interface_dns_addr(const struct interface *iface, struct in6_addr *addr)
 369 {
 370         time_t now = odhcpd_time();
 371         ssize_t m = -1;
 372
 373         for (size_t i = 0; i < iface->ia_addr_len; ++i) {
 374                 if (iface->ia_addr[i].valid <= (uint32_t)now)
 375                         continue;
 376
 377                 if (m < 0) {
 378                         m = i;
 379                         continue;
 380                 }
 381
 382                 if (iface->ia_addr[m].preferred >= (uint32_t)now &&
 383                                 iface->ia_addr[i].preferred < (uint32_t)now)
 384                         continue;
 385
 386                 if (IN6_IS_ADDR_ULA(&iface->ia_addr[i].addr)) {
 387                         if (!IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr)) {
 388                                 m = i;
 389                                 continue;
 390                         }
 391                 } else if (IN6_IS_ADDR_ULA(&iface->ia_addr[m].addr))
 392                         continue;
 393
 394                 if (iface->ia_addr[i].preferred > iface->ia_addr[m].preferred)
 395                         m = i;
 396         }
 397
 398         if (m >= 0) {
 399                 *addr = iface->ia_addr[m].addr;
 400                 return 0;
 401         }
 402
 403         return odhcpd_get_linklocal_interface_address(iface->ifindex, addr);
 404 }
 405
 406 int odhcpd_setup_route(const struct in6_addr *addr, const int prefixlen,
 407                 const struct interface *iface, const struct in6_addr *gw,
 408                 const uint32_t metric, const bool add)
 409 {
 410         struct nl_msg *msg;
 411         struct rtmsg rtm = {
 412                 .rtm_family = AF_INET6,
 413                 .rtm_dst_len = prefixlen,
 414                 .rtm_src_len = 0,
 415                 .rtm_table = RT_TABLE_MAIN,
 416                 .rtm_protocol = (add ? RTPROT_STATIC : RTPROT_UNSPEC),
 417                 .rtm_scope = (add ? (gw ? RT_SCOPE_UNIVERSE : RT_SCOPE_LINK) : RT_SCOPE_NOWHERE),
 418                 .rtm_type = (add ? RTN_UNICAST : RTN_UNSPEC),
 419         };
 420         int ret = 0;
 421
 422         msg = nlmsg_alloc_simple(add ? RTM_NEWROUTE : RTM_DELROUTE,
 423                                         add ? NLM_F_CREATE | NLM_F_REPLACE : 0);
 424         if (!msg)
 425                 return -1;
 426
 427         nlmsg_append(msg, &rtm, sizeof(rtm), 0);
 428
 429         nla_put(msg, RTA_DST, sizeof(*addr), addr);
 430         nla_put_u32(msg, RTA_OIF, iface->ifindex);
 431         nla_put_u32(msg, RTA_PRIORITY, metric);
 432
 433         if (gw)
 434                 nla_put(msg, RTA_GATEWAY, sizeof(*gw), gw);
 435
 436         ret = nl_send_auto_complete(rtnl_socket, msg);
 437         nlmsg_free(msg);
 438
 439         if (ret < 0)
 440                 return ret;
 441
 442         return nl_wait_for_ack(rtnl_socket);
 443 }
 444
 445 int odhcpd_setup_proxy_neigh(const struct in6_addr *addr,
 446                 const struct interface *iface, const bool add)
 447 {
 448         struct nl_msg *msg;
 449         struct ndmsg ndm = {
 450                 .ndm_family = AF_INET6,
 451                 .ndm_flags = NTF_PROXY,
 452                 .ndm_ifindex = iface->ifindex,
 453         };
 454         int ret = 0, flags = NLM_F_REQUEST;
 455
 456         if (add)
 457                 flags |= NLM_F_REPLACE | NLM_F_CREATE;
 458
 459         msg = nlmsg_alloc_simple(add ? RTM_NEWNEIGH : RTM_DELNEIGH, flags);
 460         if (!msg)
 461                 return -1;
 462
 463         nlmsg_append(msg, &ndm, sizeof(ndm), 0);
 464
 465         nla_put(msg, NDA_DST, sizeof(*addr), addr);
 466
 467         ret = nl_send_auto_complete(rtnl_socket, msg);
 468         nlmsg_free(msg);
 469
 470         if (ret < 0)
 471                 return ret;
 472
 473         return nl_wait_for_ack(rtnl_socket);
 474 }
 475
 476 struct interface* odhcpd_get_interface_by_index(int ifindex)
 477 {
 478         struct interface *iface;
 479         list_for_each_entry(iface, &interfaces, head)
 480                 if (iface->ifindex == ifindex)
 481                         return iface;
 482
 483         return NULL;
 484 }
 485
 486
 487 struct interface* odhcpd_get_interface_by_name(const char *name)
 488 {
 489         struct interface *iface;
 490         list_for_each_entry(iface, &interfaces, head)
 491                 if (!strcmp(iface->ifname, name))
 492                         return iface;
 493
 494         return NULL;
 495 }
 496
 497
 498 struct interface* odhcpd_get_master_interface(void)
 499 {
 500         struct interface *iface;
 501         list_for_each_entry(iface, &interfaces, head)
 502                 if (iface->master)
 503                         return iface;
 504
 505         return NULL;
 506 }
 507
 508
 509 // Convenience function to receive and do basic validation of packets
 510 static void odhcpd_receive_packets(struct uloop_fd *u, _unused unsigned int events)
 511 {
 512         struct odhcpd_event *e = container_of(u, struct odhcpd_event, uloop);
 513
 514         uint8_t data_buf[RELAYD_BUFFER_SIZE], cmsg_buf[128];
 515         union {
 516                 struct sockaddr_in6 in6;
 517                 struct sockaddr_in in;
 518                 struct sockaddr_ll ll;
 519                 struct sockaddr_nl nl;
 520         } addr;
 521
 522         if (u->error) {
 523                 int ret = -1;
 524                 socklen_t ret_len = sizeof(ret);
 525                 getsockopt(u->fd, SOL_SOCKET, SO_ERROR, &ret, &ret_len);
 526                 u->error = false;
 527                 if (e->handle_error)
 528                         e->handle_error(e, ret);
 529         }
 530
 531         if (e->recv_msgs) {
 532                 e->recv_msgs(e);
 533                 return;
 534         }
 535
 536         while (true) {
 537                 struct iovec iov = {data_buf, sizeof(data_buf)};
 538                 struct msghdr msg = {
 539                         .msg_name = (void *) &addr,
 540                         .msg_namelen = sizeof(addr),
 541                         .msg_iov = &iov,
 542                         .msg_iovlen = 1,
 543                         .msg_control = cmsg_buf,
 544                         .msg_controllen = sizeof(cmsg_buf),
 545                         .msg_flags = 0
 546                 };
 547
 548                 ssize_t len = recvmsg(u->fd, &msg, MSG_DONTWAIT);
 549                 if (len < 0) {
 550                         if (errno == EAGAIN)
 551                                 break;
 552                         else
 553                                 continue;
 554                 }
 555
 556
 557                 // Extract destination interface
 558                 int destiface = 0;
 559                 int *hlim = NULL;
 560                 void *dest = NULL;
 561                 struct in6_pktinfo *pktinfo;
 562                 struct in_pktinfo *pkt4info;
 563                 for (struct cmsghdr *ch = CMSG_FIRSTHDR(&msg); ch != NULL; ch = CMSG_NXTHDR(&msg, ch)) {
 564                         if (ch->cmsg_level == IPPROTO_IPV6 &&
 565                                         ch->cmsg_type == IPV6_PKTINFO) {
 566                                 pktinfo = (struct in6_pktinfo*)CMSG_DATA(ch);
 567                                 destiface = pktinfo->ipi6_ifindex;
 568                                 dest = &pktinfo->ipi6_addr;
 569                         } else if (ch->cmsg_level == IPPROTO_IP &&
 570                                         ch->cmsg_type == IP_PKTINFO) {
 571                                 pkt4info = (struct in_pktinfo*)CMSG_DATA(ch);
 572                                 destiface = pkt4info->ipi_ifindex;
 573                                 dest = &pkt4info->ipi_addr;
 574                         } else if (ch->cmsg_level == IPPROTO_IPV6 &&
 575                                         ch->cmsg_type == IPV6_HOPLIMIT) {
 576                                 hlim = (int*)CMSG_DATA(ch);
 577                         }
 578                 }
 579
 580                 // Check hoplimit if received
 581                 if (hlim && *hlim != 255)
 582                         continue;
 583
 584                 // Detect interface for packet sockets
 585                 if (addr.ll.sll_family == AF_PACKET)
 586                         destiface = addr.ll.sll_ifindex;
 587
 588                 struct interface *iface =
 589                                 odhcpd_get_interface_by_index(destiface);
 590
 591                 if (!iface && addr.nl.nl_family != AF_NETLINK)
 592                         continue;
 593
 594                 char ipbuf[INET6_ADDRSTRLEN] = "kernel";
 595                 if (addr.ll.sll_family == AF_PACKET &&
 596                                 len >= (ssize_t)sizeof(struct ip6_hdr))
 597                         inet_ntop(AF_INET6, &data_buf[8], ipbuf, sizeof(ipbuf));
 598                 else if (addr.in6.sin6_family == AF_INET6)
 599                         inet_ntop(AF_INET6, &addr.in6.sin6_addr, ipbuf, sizeof(ipbuf));
 600                 else if (addr.in.sin_family == AF_INET)
 601                         inet_ntop(AF_INET, &addr.in.sin_addr, ipbuf, sizeof(ipbuf));
 602
 603                 syslog(LOG_DEBUG, "Received %li Bytes from %s%%%s", (long)len,
 604                                 ipbuf, (iface) ? iface->ifname : "netlink");
 605
 606                 e->handle_dgram(&addr, data_buf, len, iface, dest);
 607         }
 608 }
 609
 610 // Register events for the multiplexer
 611 int odhcpd_register(struct odhcpd_event *event)
 612 {
 613         event->uloop.cb = odhcpd_receive_packets;
 614         return uloop_fd_add(&event->uloop, ULOOP_READ |
 615                         ((event->handle_error) ? ULOOP_ERROR_CB : 0));
 616 }
 617
 618 int odhcpd_deregister(struct odhcpd_event *event)
 619 {
 620         event->uloop.cb = NULL;
 621         return uloop_fd_delete(&event->uloop);
 622 }
 623
 624 void odhcpd_process(struct odhcpd_event *event)
 625 {
 626         odhcpd_receive_packets(&event->uloop, 0);
 627 }
 628
 629 int odhcpd_urandom(void *data, size_t len)
 630 {
 631         return read(urandom_fd, data, len);
 632 }
 633
 634
 635 time_t odhcpd_time(void)
 636 {
 637         struct timespec ts;
 638         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts);
 639         return ts.tv_sec;
 640 }
 641
 642
 643 static const char hexdigits[] = "0123456789abcdef";
 644 static const int8_t hexvals[] = {
 645     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
 646     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 647     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 648      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -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     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 652     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
 653 };
 654
 655 ssize_t odhcpd_unhexlify(uint8_t *dst, size_t len, const char *src)
 656 {
 657         size_t c;
 658         for (c = 0; c < len && src[0] && src[1]; ++c) {
 659                 int8_t x = (int8_t)*src++;
 660                 int8_t y = (int8_t)*src++;
 661                 if (x < 0 || (x = hexvals[x]) < 0
 662                                 || y < 0 || (y = hexvals[y]) < 0)
 663                         return -1;
 664                 dst[c] = x << 4 | y;
 665                 while (((int8_t)*src) < 0 ||
 666                                 (*src && hexvals[(uint8_t)*src] < 0))
 667                         src++;
 668         }
 669
 670         return c;
 671 }
 672
 673
 674 void odhcpd_hexlify(char *dst, const uint8_t *src, size_t len)
 675 {
 676         for (size_t i = 0; i < len; ++i) {
 677                 *dst++ = hexdigits[src[i] >> 4];
 678                 *dst++ = hexdigits[src[i] & 0x0f];
 679         }
 680         *dst = 0;
 681 }
 682
 683
 684 int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits)
 685 {
 686         const uint8_t *a = av, *b = bv;
 687         size_t bytes = bits / 8;
 688         bits %= 8;
 689
 690         int res = memcmp(a, b, bytes);
 691         if (res == 0 && bits > 0)
 692                 res = (a[bytes] >> (8 - bits)) - (b[bytes] >> (8 - bits));
 693
 694         return res;
 695 }
 696
 697
 698 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits)
 699 {
 700         uint8_t *a = av;
 701         const uint8_t *b = bv;
 702
 703         size_t bytes = bits / 8;
 704         bits %= 8;
 705         memcpy(a, b, bytes);
 706
 707         if (bits > 0) {
 708                 uint8_t mask = (1 << (8 - bits)) - 1;
 709                 a[bytes] = (a[bytes] & mask) | ((~mask) & b[bytes]);
 710         }
 711 }