release/src/router/dnsmasq/src/helper.c

   1 /* dnsmasq is Copyright (c) 2000-2013 Simon Kelley
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 dated June, 1991, or
   6    (at your option) version 3 dated 29 June, 2007.
   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    You should have received a copy of the GNU General Public License
  14    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #include "dnsmasq.h"
  18
  19 #ifdef HAVE_SCRIPT
  20
  21 /* This file has code to fork a helper process which recieves data via a pipe
  22    shared with the main process and which is responsible for calling a script when
  23    DHCP leases change.
  24
  25    The helper process is forked before the main process drops root, so it retains root
  26    privs to pass on to the script. For this reason it tries to be paranoid about
  27    data received from the main process, in case that has been compromised. We don't
  28    want the helper to give an attacker root. In particular, the script to be run is
  29    not settable via the pipe, once the fork has taken place it is not alterable by the
  30    main process.
  31 */
  32
  33 static void my_setenv(const char *name, const char *value, int *error);
  34 static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  char *env, int *err);
  35
  36 #ifdef HAVE_LUASCRIPT
  37 #define LUA_COMPAT_ALL
  38 #include <lua.h>
  39 #include <lualib.h>
  40 #include <lauxlib.h>
  41
  42 #ifndef lua_open
  43 #define lua_open()     luaL_newstate()
  44 #endif
  45
  46 lua_State *lua;
  47
  48 static unsigned char *grab_extradata_lua(unsigned char *buf, unsigned char *end, char *field);
  49 #endif
  50
  51
  52 struct script_data
  53 {
  54   int flags;
  55   int action, hwaddr_len, hwaddr_type;
  56   int clid_len, hostname_len, ed_len;
  57   struct in_addr addr, giaddr;
  58   unsigned int remaining_time;
  59 #ifdef HAVE_BROKEN_RTC
  60   unsigned int length;
  61 #else
  62   time_t expires;
  63 #endif
  64   unsigned char hwaddr[DHCP_CHADDR_MAX];
  65   char interface[IF_NAMESIZE];
  66
  67 };
  68
  69 static struct script_data *buf = NULL;
  70 static size_t bytes_in_buf = 0, buf_size = 0;
  71
  72 int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
  73 {
  74   pid_t pid;
  75   int i, pipefd[2];
  76   struct sigaction sigact;
  77
  78   /* create the pipe through which the main program sends us commands,
  79      then fork our process. */
  80   if (pipe(pipefd) == -1 || !fix_fd(pipefd[1]) || (pid = fork()) == -1)
  81     {
  82       send_event(err_fd, EVENT_PIPE_ERR, errno, NULL);
  83       _exit(0);
  84     }
  85
  86   if (pid != 0)
  87     {
  88       close(pipefd[0]); /* close reader side */
  89       return pipefd[1];
  90     }
  91
  92   /* ignore SIGTERM, so that we can clean up when the main process gets hit
  93      and SIGALRM so that we can use sleep() */
  94   sigact.sa_handler = SIG_IGN;
  95   sigact.sa_flags = 0;
  96   sigemptyset(&sigact.sa_mask);
  97   sigaction(SIGTERM, &sigact, NULL);
  98   sigaction(SIGALRM, &sigact, NULL);
  99
 100   if (!option_bool(OPT_DEBUG) && uid != 0)
 101     {
 102       gid_t dummy;
 103       if (setgroups(0, &dummy) == -1 ||
 104           setgid(gid) == -1 ||
 105           setuid(uid) == -1)
 106         {
 107           if (option_bool(OPT_NO_FORK))
 108             /* send error to daemon process if no-fork */
 109             send_event(event_fd, EVENT_USER_ERR, errno, daemon->scriptuser);
 110           else
 111             {
 112               /* kill daemon */
 113               send_event(event_fd, EVENT_DIE, 0, NULL);
 114               /* return error */
 115               send_event(err_fd, EVENT_USER_ERR, errno, daemon->scriptuser);
 116             }
 117           _exit(0);
 118         }
 119     }
 120
 121   /* close all the sockets etc, we don't need them here.
 122      Don't close err_fd, in case the lua-init fails.
 123      Note that we have to do this before lua init
 124      so we don't close any lua fds. */
 125   for (max_fd--; max_fd >= 0; max_fd--)
 126     if (max_fd != STDOUT_FILENO && max_fd != STDERR_FILENO &&
 127         max_fd != STDIN_FILENO && max_fd != pipefd[0] &&
 128         max_fd != event_fd && max_fd != err_fd)
 129       close(max_fd);
 130
 131 #ifdef HAVE_LUASCRIPT
 132   if (daemon->luascript)
 133     {
 134       const char *lua_err = NULL;
 135       lua = lua_open();
 136       luaL_openlibs(lua);
 137
 138       /* get Lua to load our script file */
 139       if (luaL_dofile(lua, daemon->luascript) != 0)
 140         lua_err = lua_tostring(lua, -1);
 141       else
 142         {
 143           lua_getglobal(lua, "lease");
 144           if (lua_type(lua, -1) != LUA_TFUNCTION)
 145             lua_err = _("lease() function missing in Lua script");
 146         }
 147
 148       if (lua_err)
 149         {
 150           if (option_bool(OPT_NO_FORK) || option_bool(OPT_DEBUG))
 151             /* send error to daemon process if no-fork */
 152             send_event(event_fd, EVENT_LUA_ERR, 0, (char *)lua_err);
 153           else
 154             {
 155               /* kill daemon */
 156               send_event(event_fd, EVENT_DIE, 0, NULL);
 157               /* return error */
 158               send_event(err_fd, EVENT_LUA_ERR, 0, (char *)lua_err);
 159             }
 160           _exit(0);
 161         }
 162
 163       lua_pop(lua, 1);  /* remove nil from stack */
 164       lua_getglobal(lua, "init");
 165       if (lua_type(lua, -1) == LUA_TFUNCTION)
 166         lua_call(lua, 0, 0);
 167       else
 168         lua_pop(lua, 1);  /* remove nil from stack */
 169     }
 170 #endif
 171
 172   /* All init done, close our copy of the error pipe, so that main process can return */
 173   if (err_fd != -1)
 174     close(err_fd);
 175
 176   /* loop here */
 177   while(1)
 178     {
 179       struct script_data data;
 180       char *p, *action_str, *hostname = NULL, *domain = NULL;
 181       unsigned char *buf = (unsigned char *)daemon->namebuff;
 182       unsigned char *end, *extradata, *alloc_buff = NULL;
 183       int is6, err = 0;
 184
 185       free(alloc_buff);
 186
 187       /* we read zero bytes when pipe closed: this is our signal to exit */
 188       if (!read_write(pipefd[0], (unsigned char *)&data, sizeof(data), 1))
 189         {
 190 #ifdef HAVE_LUASCRIPT
 191           if (daemon->luascript)
 192             {
 193               lua_getglobal(lua, "shutdown");
 194               if (lua_type(lua, -1) == LUA_TFUNCTION)
 195                 lua_call(lua, 0, 0);
 196             }
 197 #endif
 198           _exit(0);
 199         }
 200
 201       is6 = !!(data.flags & (LEASE_TA | LEASE_NA));
 202
 203       if (data.action == ACTION_DEL)
 204         action_str = "del";
 205       else if (data.action == ACTION_ADD)
 206         action_str = "add";
 207       else if (data.action == ACTION_OLD || data.action == ACTION_OLD_HOSTNAME)
 208         action_str = "old";
 209       else if (data.action == ACTION_TFTP)
 210         {
 211           action_str = "tftp";
 212           is6 = (data.flags != AF_INET);
 213         }
 214       else
 215         continue;
 216
 217
 218       if (!is6)
 219         {
 220           /* stringify MAC into dhcp_buff */
 221           p = daemon->dhcp_buff;
 222           if (data.hwaddr_type != ARPHRD_ETHER || data.hwaddr_len == 0)
 223             p += sprintf(p, "%.2x-", data.hwaddr_type);
 224           for (i = 0; (i < data.hwaddr_len) && (i < DHCP_CHADDR_MAX); i++)
 225             {
 226               p += sprintf(p, "%.2x", data.hwaddr[i]);
 227               if (i != data.hwaddr_len - 1)
 228                 p += sprintf(p, ":");
 229             }
 230         }
 231
 232       /* supplied data may just exceed normal buffer (unlikely) */
 233       if ((data.hostname_len + data.ed_len + data.clid_len) > MAXDNAME &&
 234           !(alloc_buff = buf = malloc(data.hostname_len + data.ed_len + data.clid_len)))
 235         continue;
 236
 237       if (!read_write(pipefd[0], buf,
 238                       data.hostname_len + data.ed_len + data.clid_len, 1))
 239         continue;
 240
 241       /* CLID into packet */
 242       if (!is6)
 243         for (p = daemon->packet, i = 0; i < data.clid_len; i++)
 244           {
 245             p += sprintf(p, "%.2x", buf[i]);
 246             if (i != data.clid_len - 1)
 247               p += sprintf(p, ":");
 248           }
 249 #ifdef HAVE_DHCP6
 250       else
 251         {
 252           /* or IAID and server DUID for IPv6 */
 253           sprintf(daemon->dhcp_buff3, "%s%u", data.flags & LEASE_TA ? "T" : "", data.hwaddr_type);
 254           for (p = daemon->packet, i = 0; i < daemon->duid_len; i++)
 255             {
 256               p += sprintf(p, "%.2x", daemon->duid[i]);
 257               if (i != daemon->duid_len - 1)
 258                 p += sprintf(p, ":");
 259             }
 260
 261           /* duid not MAC for IPv6 */
 262           for (p = daemon->dhcp_buff, i = 0; i < data.clid_len; i++)
 263             {
 264               p += sprintf(p, "%.2x", buf[i]);
 265               if (i != data.clid_len - 1)
 266                 p += sprintf(p, ":");
 267             }
 268         }
 269 #endif
 270
 271       buf += data.clid_len;
 272
 273       if (data.hostname_len != 0)
 274         {
 275           char *dot;
 276           hostname = (char *)buf;
 277           hostname[data.hostname_len - 1] = 0;
 278           if (data.action != ACTION_TFTP)
 279             {
 280               if (!legal_hostname(hostname))
 281                 hostname = NULL;
 282               else if ((dot = strchr(hostname, '.')))
 283                 {
 284                   domain = dot+1;
 285                   *dot = 0;
 286                 }
 287             }
 288         }
 289
 290       extradata = buf + data.hostname_len;
 291
 292       if (!is6)
 293         inet_ntop(AF_INET, &data.addr, daemon->addrbuff, ADDRSTRLEN);
 294 #ifdef HAVE_DHCP6
 295       else
 296         inet_ntop(AF_INET6, &data.hwaddr, daemon->addrbuff, ADDRSTRLEN);
 297 #endif
 298
 299       /* file length */
 300       if (data.action == ACTION_TFTP)
 301         sprintf(daemon->dhcp_buff, "%u", data.hwaddr_len);
 302
 303 #ifdef HAVE_LUASCRIPT
 304       if (daemon->luascript)
 305         {
 306           if (data.action == ACTION_TFTP)
 307             {
 308               lua_getglobal(lua, "tftp");
 309               if (lua_type(lua, -1) != LUA_TFUNCTION)
 310                 lua_pop(lua, 1); /* tftp function optional */
 311               else
 312                 {
 313                   lua_pushstring(lua, action_str); /* arg1 - action */
 314                   lua_newtable(lua);               /* arg2 - data table */
 315                   lua_pushstring(lua, daemon->addrbuff);
 316                   lua_setfield(lua, -2, "destination_address");
 317                   lua_pushstring(lua, hostname);
 318                   lua_setfield(lua, -2, "file_name");
 319                   lua_pushstring(lua, daemon->dhcp_buff);
 320                   lua_setfield(lua, -2, "file_size");
 321                   lua_call(lua, 2, 0);  /* pass 2 values, expect 0 */
 322                 }
 323             }
 324           else
 325             {
 326               lua_getglobal(lua, "lease");     /* function to call */
 327               lua_pushstring(lua, action_str); /* arg1 - action */
 328               lua_newtable(lua);               /* arg2 - data table */
 329
 330               if (is6)
 331                 {
 332                   lua_pushstring(lua, daemon->dhcp_buff);
 333                   lua_setfield(lua, -2, "client_duid");
 334                   lua_pushstring(lua, daemon->packet);
 335                   lua_setfield(lua, -2, "server_duid");
 336                   lua_pushstring(lua, daemon->dhcp_buff3);
 337                   lua_setfield(lua, -2, "iaid");
 338                 }
 339
 340               if (!is6 && data.clid_len != 0)
 341                 {
 342                   lua_pushstring(lua, daemon->packet);
 343                   lua_setfield(lua, -2, "client_id");
 344                 }
 345
 346               if (strlen(data.interface) != 0)
 347                 {
 348                   lua_pushstring(lua, data.interface);
 349                   lua_setfield(lua, -2, "interface");
 350                 }
 351
 352 #ifdef HAVE_BROKEN_RTC
 353               lua_pushnumber(lua, data.length);
 354               lua_setfield(lua, -2, "lease_length");
 355 #else
 356               lua_pushnumber(lua, data.expires);
 357               lua_setfield(lua, -2, "lease_expires");
 358 #endif
 359
 360               if (hostname)
 361                 {
 362                   lua_pushstring(lua, hostname);
 363                   lua_setfield(lua, -2, "hostname");
 364                 }
 365
 366               if (domain)
 367                 {
 368                   lua_pushstring(lua, domain);
 369                   lua_setfield(lua, -2, "domain");
 370                 }
 371
 372               end = extradata + data.ed_len;
 373               buf = extradata;
 374
 375               if (!is6)
 376                 buf = grab_extradata_lua(buf, end, "vendor_class");
 377 #ifdef HAVE_DHCP6
 378               else
 379                 for (i = 0; i < data.hwaddr_len; i++)
 380                   {
 381                     sprintf(daemon->dhcp_buff2, "vendor_class%i", i);
 382                     buf = grab_extradata_lua(buf, end, daemon->dhcp_buff2);
 383                   }
 384 #endif
 385
 386               buf = grab_extradata_lua(buf, end, "supplied_hostname");
 387
 388               if (!is6)
 389                 {
 390                   buf = grab_extradata_lua(buf, end, "cpewan_oui");
 391                   buf = grab_extradata_lua(buf, end, "cpewan_serial");
 392                   buf = grab_extradata_lua(buf, end, "cpewan_class");
 393                   buf = grab_extradata_lua(buf, end, "circuit_id");
 394                   buf = grab_extradata_lua(buf, end, "subscriber_id");
 395                   buf = grab_extradata_lua(buf, end, "remote_id");
 396                 }
 397
 398               buf = grab_extradata_lua(buf, end, "tags");
 399
 400               if (is6)
 401                 buf = grab_extradata_lua(buf, end, "relay_address");
 402               else if (data.giaddr.s_addr != 0)
 403                 {
 404                   lua_pushstring(lua, inet_ntoa(data.giaddr));
 405                   lua_setfield(lua, -2, "relay_address");
 406                 }
 407
 408               for (i = 0; buf; i++)
 409                 {
 410                   sprintf(daemon->dhcp_buff2, "user_class%i", i);
 411                   buf = grab_extradata_lua(buf, end, daemon->dhcp_buff2);
 412                 }
 413
 414               if (data.action != ACTION_DEL && data.remaining_time != 0)
 415                 {
 416                   lua_pushnumber(lua, data.remaining_time);
 417                   lua_setfield(lua, -2, "time_remaining");
 418                 }
 419
 420               if (data.action == ACTION_OLD_HOSTNAME && hostname)
 421                 {
 422                   lua_pushstring(lua, hostname);
 423                   lua_setfield(lua, -2, "old_hostname");
 424                 }
 425
 426               if (!is6)
 427                 {
 428                   lua_pushstring(lua, daemon->dhcp_buff);
 429                   lua_setfield(lua, -2, "mac_address");
 430                 }
 431
 432               lua_pushstring(lua, daemon->addrbuff);
 433               lua_setfield(lua, -2, "ip_address");
 434
 435               lua_call(lua, 2, 0);      /* pass 2 values, expect 0 */
 436             }
 437         }
 438 #endif
 439
 440       /* no script, just lua */
 441       if (!daemon->lease_change_command)
 442         continue;
 443
 444       /* possible fork errors are all temporary resource problems */
 445       while ((pid = fork()) == -1 && (errno == EAGAIN || errno == ENOMEM))
 446         sleep(2);
 447
 448       if (pid == -1)
 449         continue;
 450
 451       /* wait for child to complete */
 452       if (pid != 0)
 453         {
 454           /* reap our children's children, if necessary */
 455           while (1)
 456             {
 457               int status;
 458               pid_t rc = wait(&status);
 459
 460               if (rc == pid)
 461                 {
 462                   /* On error send event back to main process for logging */
 463                   if (WIFSIGNALED(status))
 464                     send_event(event_fd, EVENT_KILLED, WTERMSIG(status), NULL);
 465                   else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
 466                     send_event(event_fd, EVENT_EXITED, WEXITSTATUS(status), NULL);
 467                   break;
 468                 }
 469
 470               if (rc == -1 && errno != EINTR)
 471                 break;
 472             }
 473
 474           continue;
 475         }
 476
 477       if (data.action != ACTION_TFTP)
 478         {
 479           if (is6)
 480             {
 481               my_setenv("DNSMASQ_IAID", daemon->dhcp_buff3, &err);
 482               my_setenv("DNSMASQ_SERVER_DUID", daemon->packet, &err);
 483             }
 484
 485           if (!is6 && data.clid_len != 0)
 486             my_setenv("DNSMASQ_CLIENT_ID", daemon->packet, &err);
 487
 488           if (strlen(data.interface) != 0)
 489             my_setenv("DNSMASQ_INTERFACE", data.interface, &err);
 490
 491 #ifdef HAVE_BROKEN_RTC
 492           sprintf(daemon->dhcp_buff2, "%u", data.length);
 493           my_setenv("DNSMASQ_LEASE_LENGTH", daemon->dhcp_buff2, &err);
 494 #else
 495           sprintf(daemon->dhcp_buff2, "%lu", (unsigned long)data.expires);
 496           my_setenv("DNSMASQ_LEASE_EXPIRES", daemon->dhcp_buff2, &err);
 497 #endif
 498
 499           if (domain)
 500             my_setenv("DNSMASQ_DOMAIN", domain, &err);
 501
 502           end = extradata + data.ed_len;
 503           buf = extradata;
 504
 505           if (!is6)
 506             buf = grab_extradata(buf, end, "DNSMASQ_VENDOR_CLASS", &err);
 507 #ifdef HAVE_DHCP6
 508           else
 509             {
 510               if (data.hwaddr_len != 0)
 511                 {
 512                   buf = grab_extradata(buf, end, "DNSMASQ_VENDOR_CLASS_ID", &err);
 513                   for (i = 0; i < data.hwaddr_len - 1; i++)
 514                     {
 515                       sprintf(daemon->dhcp_buff2, "DNSMASQ_VENDOR_CLASS%i", i);
 516                       buf = grab_extradata(buf, end, daemon->dhcp_buff2, &err);
 517                     }
 518                 }
 519             }
 520 #endif
 521
 522           buf = grab_extradata(buf, end, "DNSMASQ_SUPPLIED_HOSTNAME", &err);
 523
 524           if (!is6)
 525             {
 526               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_OUI", &err);
 527               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_SERIAL", &err);
 528               buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_CLASS", &err);
 529               buf = grab_extradata(buf, end, "DNSMASQ_CIRCUIT_ID", &err);
 530               buf = grab_extradata(buf, end, "DNSMASQ_SUBSCRIBER_ID", &err);
 531               buf = grab_extradata(buf, end, "DNSMASQ_REMOTE_ID", &err);
 532             }
 533
 534           buf = grab_extradata(buf, end, "DNSMASQ_TAGS", &err);
 535
 536           if (is6)
 537             buf = grab_extradata(buf, end, "DNSMASQ_RELAY_ADDRESS", &err);
 538           else if (data.giaddr.s_addr != 0)
 539             my_setenv("DNSMASQ_RELAY_ADDRESS", inet_ntoa(data.giaddr), &err);
 540
 541           for (i = 0; buf; i++)
 542             {
 543               sprintf(daemon->dhcp_buff2, "DNSMASQ_USER_CLASS%i", i);
 544               buf = grab_extradata(buf, end, daemon->dhcp_buff2, &err);
 545             }
 546
 547           if (data.action != ACTION_DEL && data.remaining_time != 0)
 548             {
 549               sprintf(daemon->dhcp_buff2, "%u", data.remaining_time);
 550               my_setenv("DNSMASQ_TIME_REMAINING", daemon->dhcp_buff2, &err);
 551             }
 552
 553           if (data.action == ACTION_OLD_HOSTNAME && hostname)
 554             {
 555               my_setenv("DNSMASQ_OLD_HOSTNAME", hostname, &err);
 556               hostname = NULL;
 557             }
 558         }
 559
 560       if (option_bool(OPT_LOG_OPTS))
 561         my_setenv("DNSMASQ_LOG_DHCP", "1", &err);
 562
 563       /* we need to have the event_fd around if exec fails */
 564       if ((i = fcntl(event_fd, F_GETFD)) != -1)
 565         fcntl(event_fd, F_SETFD, i | FD_CLOEXEC);
 566       close(pipefd[0]);
 567
 568       p =  strrchr(daemon->lease_change_command, '/');
 569       if (err == 0)
 570         {
 571           execl(daemon->lease_change_command,
 572                 p ? p+1 : daemon->lease_change_command,
 573                 action_str, daemon->dhcp_buff, daemon->addrbuff, hostname, (char*)NULL);
 574           err = errno;
 575         }
 576       /* failed, send event so the main process logs the problem */
 577       send_event(event_fd, EVENT_EXEC_ERR, err, NULL);
 578       _exit(0);
 579     }
 580 }
 581
 582 static void my_setenv(const char *name, const char *value, int *error)
 583 {
 584   if (*error == 0 && setenv(name, value, 1) != 0)
 585     *error = errno;
 586 }
 587
 588 static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  char *env, int *err)
 589 {
 590   unsigned char *next;
 591
 592   if (!buf || (buf == end))
 593     return NULL;
 594
 595   for (next = buf; *next != 0; next++)
 596     if (next == end)
 597       return NULL;
 598
 599   if (next != buf)
 600     {
 601       char *p;
 602       /* No "=" in value */
 603       if ((p = strchr((char *)buf, '=')))
 604         *p = 0;
 605       my_setenv(env, (char *)buf, err);
 606     }
 607
 608   return next + 1;
 609 }
 610
 611 #ifdef HAVE_LUASCRIPT
 612 static unsigned char *grab_extradata_lua(unsigned char *buf, unsigned char *end, char *field)
 613 {
 614   unsigned char *next;
 615
 616   if (!buf || (buf == end))
 617     return NULL;
 618
 619   for (next = buf; *next != 0; next++)
 620     if (next == end)
 621       return NULL;
 622
 623   if (next != buf)
 624     {
 625       lua_pushstring(lua,  (char *)buf);
 626       lua_setfield(lua, -2, field);
 627     }
 628
 629   return next + 1;
 630 }
 631 #endif
 632
 633 static void buff_alloc(size_t size)
 634 {
 635   if (size > buf_size)
 636     {
 637       struct script_data *new;
 638
 639       /* start with reasonable size, will almost never need extending. */
 640       if (size < sizeof(struct script_data) + 200)
 641         size = sizeof(struct script_data) + 200;
 642
 643       if (!(new = whine_malloc(size)))
 644         return;
 645       if (buf)
 646         free(buf);
 647       buf = new;
 648       buf_size = size;
 649     }
 650 }
 651
 652 /* pack up lease data into a buffer */
 653 void queue_script(int action, struct dhcp_lease *lease, char *hostname, time_t now)
 654 {
 655   unsigned char *p;
 656   unsigned int hostname_len = 0, clid_len = 0, ed_len = 0;
 657   int fd = daemon->dhcpfd;
 658 #ifdef HAVE_DHCP6
 659   int is6 = !!(lease->flags & (LEASE_TA | LEASE_NA));
 660
 661   if (!daemon->dhcp)
 662     fd = daemon->dhcp6fd;
 663 #endif
 664
 665   /* no script */
 666   if (daemon->helperfd == -1)
 667     return;
 668
 669   if (lease->extradata)
 670     ed_len = lease->extradata_len;
 671   if (lease->clid)
 672     clid_len = lease->clid_len;
 673   if (hostname)
 674     hostname_len = strlen(hostname) + 1;
 675
 676   buff_alloc(sizeof(struct script_data) +  clid_len + ed_len + hostname_len);
 677
 678   buf->action = action;
 679   buf->flags = lease->flags;
 680 #ifdef HAVE_DHCP6
 681   if (is6)
 682     buf->hwaddr_len = lease->vendorclass_count;
 683   else
 684 #endif
 685     buf->hwaddr_len = lease->hwaddr_len;
 686   buf->hwaddr_type = lease->hwaddr_type;
 687   buf->clid_len = clid_len;
 688   buf->ed_len = ed_len;
 689   buf->hostname_len = hostname_len;
 690   buf->addr = lease->addr;
 691   buf->giaddr = lease->giaddr;
 692   memcpy(buf->hwaddr, lease->hwaddr, DHCP_CHADDR_MAX);
 693   if (!indextoname(fd, lease->last_interface, buf->interface))
 694     buf->interface[0] = 0;
 695
 696 #ifdef HAVE_BROKEN_RTC
 697   buf->length = lease->length;
 698 #else
 699   buf->expires = lease->expires;
 700 #endif
 701
 702   if (lease->expires != 0)
 703     buf->remaining_time = (unsigned int)difftime(lease->expires, now);
 704   else
 705     buf->remaining_time = 0;
 706
 707   p = (unsigned char *)(buf+1);
 708   if (clid_len != 0)
 709     {
 710       memcpy(p, lease->clid, clid_len);
 711       p += clid_len;
 712     }
 713   if (hostname_len != 0)
 714     {
 715       memcpy(p, hostname, hostname_len);
 716       p += hostname_len;
 717     }
 718   if (ed_len != 0)
 719     {
 720       memcpy(p, lease->extradata, ed_len);
 721       p += ed_len;
 722     }
 723   bytes_in_buf = p - (unsigned char *)buf;
 724 }
 725
 726 #ifdef HAVE_TFTP
 727 /* This nastily re-uses DHCP-fields for TFTP stuff */
 728 void queue_tftp(off_t file_len, char *filename, union mysockaddr *peer)
 729 {
 730   unsigned int filename_len;
 731
 732   /* no script */
 733   if (daemon->helperfd == -1)
 734     return;
 735
 736   filename_len = strlen(filename) + 1;
 737   buff_alloc(sizeof(struct script_data) +  filename_len);
 738   memset(buf, 0, sizeof(struct script_data));
 739
 740   buf->action = ACTION_TFTP;
 741   buf->hostname_len = filename_len;
 742   buf->hwaddr_len = file_len;
 743
 744   if ((buf->flags = peer->sa.sa_family) == AF_INET)
 745     buf->addr = peer->in.sin_addr;
 746 #ifdef HAVE_IPV6
 747   else
 748     memcpy(buf->hwaddr, &peer->in6.sin6_addr, IN6ADDRSZ);
 749 #endif
 750
 751   memcpy((unsigned char *)(buf+1), filename, filename_len);
 752
 753   bytes_in_buf = sizeof(struct script_data) +  filename_len;
 754 }
 755 #endif
 756
 757 int helper_buf_empty(void)
 758 {
 759   return bytes_in_buf == 0;
 760 }
 761
 762 void helper_write(void)
 763 {
 764   ssize_t rc;
 765
 766   if (bytes_in_buf == 0)
 767     return;
 768
 769   if ((rc = write(daemon->helperfd, buf, bytes_in_buf)) != -1)
 770     {
 771       if (bytes_in_buf != (size_t)rc)
 772         memmove(buf, buf + rc, bytes_in_buf - rc);
 773       bytes_in_buf -= rc;
 774     }
 775   else
 776     {
 777       if (errno == EAGAIN || errno == EINTR)
 778         return;
 779       bytes_in_buf = 0;
 780     }
 781 }
 782
 783 #endif
 784
 785
 786