San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 1 | /* dnsmasq is Copyright (c) 2000-2009 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 | struct daemon *daemon; |
| 20 | |
| 21 | static char *compile_opts = |
| 22 | #ifndef HAVE_IPV6 |
| 23 | "no-" |
| 24 | #endif |
| 25 | "IPv6 " |
| 26 | #ifndef HAVE_GETOPT_LONG |
| 27 | "no-" |
| 28 | #endif |
| 29 | "GNU-getopt " |
| 30 | #ifdef HAVE_BROKEN_RTC |
| 31 | "no-RTC " |
| 32 | #endif |
| 33 | #ifdef NO_FORK |
| 34 | "no-MMU " |
| 35 | #endif |
| 36 | #ifndef HAVE_DBUS |
| 37 | "no-" |
| 38 | #endif |
| 39 | "DBus " |
| 40 | #ifndef LOCALEDIR |
| 41 | "no-" |
| 42 | #endif |
| 43 | "I18N " |
| 44 | #ifndef HAVE_DHCP |
| 45 | "no-" |
| 46 | #endif |
| 47 | "DHCP " |
| 48 | #if defined(HAVE_DHCP) && !defined(HAVE_SCRIPT) |
| 49 | "no-scripts " |
| 50 | #endif |
| 51 | #ifndef HAVE_TFTP |
| 52 | "no-" |
| 53 | #endif |
| 54 | "TFTP"; |
| 55 | |
| 56 | |
| 57 | |
| 58 | static volatile pid_t pid = 0; |
| 59 | static volatile int pipewrite; |
| 60 | |
| 61 | static int set_dns_listeners(time_t now, fd_set *set, int *maxfdp); |
| 62 | static void check_dns_listeners(fd_set *set, time_t now); |
| 63 | static void sig_handler(int sig); |
| 64 | static void async_event(int pipe, time_t now); |
| 65 | static void fatal_event(struct event_desc *ev); |
| 66 | static void poll_resolv(void); |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 67 | #ifdef __ANDROID__ |
| 68 | static int set_android_listeners(fd_set *set, int *maxfdp); |
| 69 | static int check_android_listeners(fd_set *set); |
| 70 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 71 | |
| 72 | int main (int argc, char **argv) |
| 73 | { |
| 74 | int bind_fallback = 0; |
| 75 | time_t now; |
| 76 | struct sigaction sigact; |
| 77 | struct iname *if_tmp; |
| 78 | int piperead, pipefd[2], err_pipe[2]; |
| 79 | struct passwd *ent_pw = NULL; |
| 80 | #if defined(HAVE_DHCP) && defined(HAVE_SCRIPT) |
| 81 | uid_t script_uid = 0; |
| 82 | gid_t script_gid = 0; |
| 83 | #endif |
| 84 | struct group *gp = NULL; |
| 85 | long i, max_fd = sysconf(_SC_OPEN_MAX); |
| 86 | char *baduser = NULL; |
| 87 | int log_err; |
| 88 | #if defined(HAVE_LINUX_NETWORK) |
| 89 | cap_user_header_t hdr = NULL; |
| 90 | cap_user_data_t data = NULL; |
| 91 | #endif |
| 92 | |
| 93 | #ifdef LOCALEDIR |
| 94 | setlocale(LC_ALL, ""); |
| 95 | bindtextdomain("dnsmasq", LOCALEDIR); |
| 96 | textdomain("dnsmasq"); |
| 97 | #endif |
| 98 | |
| 99 | sigact.sa_handler = sig_handler; |
| 100 | sigact.sa_flags = 0; |
| 101 | sigemptyset(&sigact.sa_mask); |
| 102 | sigaction(SIGUSR1, &sigact, NULL); |
| 103 | sigaction(SIGUSR2, &sigact, NULL); |
| 104 | sigaction(SIGHUP, &sigact, NULL); |
| 105 | sigaction(SIGTERM, &sigact, NULL); |
| 106 | sigaction(SIGALRM, &sigact, NULL); |
| 107 | sigaction(SIGCHLD, &sigact, NULL); |
| 108 | |
| 109 | /* ignore SIGPIPE */ |
| 110 | sigact.sa_handler = SIG_IGN; |
| 111 | sigaction(SIGPIPE, &sigact, NULL); |
| 112 | |
| 113 | umask(022); /* known umask, create leases and pid files as 0644 */ |
| 114 | |
| 115 | read_opts(argc, argv, compile_opts); |
| 116 | |
| 117 | if (daemon->edns_pktsz < PACKETSZ) |
| 118 | daemon->edns_pktsz = PACKETSZ; |
| 119 | daemon->packet_buff_sz = daemon->edns_pktsz > DNSMASQ_PACKETSZ ? |
| 120 | daemon->edns_pktsz : DNSMASQ_PACKETSZ; |
| 121 | daemon->packet = safe_malloc(daemon->packet_buff_sz); |
| 122 | |
| 123 | #ifdef HAVE_DHCP |
| 124 | if (!daemon->lease_file) |
| 125 | { |
| 126 | if (daemon->dhcp) |
| 127 | daemon->lease_file = LEASEFILE; |
| 128 | } |
| 129 | #endif |
| 130 | |
| 131 | /* Close any file descriptors we inherited apart from std{in|out|err} */ |
| 132 | for (i = 0; i < max_fd; i++) |
| 133 | if (i != STDOUT_FILENO && i != STDERR_FILENO && i != STDIN_FILENO) |
| 134 | close(i); |
| 135 | |
| 136 | #ifdef HAVE_LINUX_NETWORK |
| 137 | netlink_init(); |
| 138 | #elif !(defined(IP_RECVDSTADDR) && \ |
| 139 | defined(IP_RECVIF) && \ |
| 140 | defined(IP_SENDSRCADDR)) |
| 141 | if (!(daemon->options & OPT_NOWILD)) |
| 142 | { |
| 143 | bind_fallback = 1; |
| 144 | daemon->options |= OPT_NOWILD; |
| 145 | } |
| 146 | #endif |
| 147 | |
| 148 | #ifndef HAVE_TFTP |
| 149 | if (daemon->options & OPT_TFTP) |
| 150 | die(_("TFTP server not available: set HAVE_TFTP in src/config.h"), NULL, EC_BADCONF); |
| 151 | #endif |
| 152 | |
| 153 | #ifdef HAVE_SOLARIS_NETWORK |
| 154 | if (daemon->max_logs != 0) |
| 155 | die(_("asychronous logging is not available under Solaris"), NULL, EC_BADCONF); |
| 156 | #endif |
| 157 | |
| 158 | rand_init(); |
| 159 | |
| 160 | now = dnsmasq_time(); |
| 161 | |
| 162 | #ifdef HAVE_DHCP |
| 163 | if (daemon->dhcp) |
| 164 | { |
| 165 | /* Note that order matters here, we must call lease_init before |
| 166 | creating any file descriptors which shouldn't be leaked |
| 167 | to the lease-script init process. */ |
| 168 | lease_init(now); |
| 169 | dhcp_init(); |
| 170 | } |
| 171 | #endif |
| 172 | |
| 173 | if (!enumerate_interfaces()) |
| 174 | die(_("failed to find list of interfaces: %s"), NULL, EC_MISC); |
| 175 | |
| 176 | if (daemon->options & OPT_NOWILD) |
| 177 | { |
| 178 | daemon->listeners = create_bound_listeners(); |
| 179 | |
| 180 | for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next) |
| 181 | if (if_tmp->name && !if_tmp->used) |
| 182 | die(_("unknown interface %s"), if_tmp->name, EC_BADNET); |
| 183 | |
| 184 | for (if_tmp = daemon->if_addrs; if_tmp; if_tmp = if_tmp->next) |
| 185 | if (!if_tmp->used) |
| 186 | { |
| 187 | prettyprint_addr(&if_tmp->addr, daemon->namebuff); |
| 188 | die(_("no interface with address %s"), daemon->namebuff, EC_BADNET); |
| 189 | } |
| 190 | } |
| 191 | else if ((daemon->port != 0 || (daemon->options & OPT_TFTP)) && |
| 192 | !(daemon->listeners = create_wildcard_listeners())) |
| 193 | die(_("failed to create listening socket: %s"), NULL, EC_BADNET); |
| 194 | |
| 195 | if (daemon->port != 0) |
| 196 | cache_init(); |
| 197 | |
| 198 | if (daemon->options & OPT_DBUS) |
| 199 | #ifdef HAVE_DBUS |
| 200 | { |
| 201 | char *err; |
| 202 | daemon->dbus = NULL; |
| 203 | daemon->watches = NULL; |
| 204 | if ((err = dbus_init())) |
| 205 | die(_("DBus error: %s"), err, EC_MISC); |
| 206 | } |
| 207 | #else |
| 208 | die(_("DBus not available: set HAVE_DBUS in src/config.h"), NULL, EC_BADCONF); |
| 209 | #endif |
| 210 | |
| 211 | if (daemon->port != 0) |
| 212 | pre_allocate_sfds(); |
| 213 | |
| 214 | #if defined(HAVE_DHCP) && defined(HAVE_SCRIPT) |
| 215 | /* Note getpwnam returns static storage */ |
| 216 | if (daemon->dhcp && daemon->lease_change_command && daemon->scriptuser) |
| 217 | { |
| 218 | if ((ent_pw = getpwnam(daemon->scriptuser))) |
| 219 | { |
| 220 | script_uid = ent_pw->pw_uid; |
| 221 | script_gid = ent_pw->pw_gid; |
| 222 | } |
| 223 | else |
| 224 | baduser = daemon->scriptuser; |
| 225 | } |
| 226 | #endif |
| 227 | |
| 228 | if (daemon->username && !(ent_pw = getpwnam(daemon->username))) |
| 229 | baduser = daemon->username; |
| 230 | else if (daemon->groupname && !(gp = getgrnam(daemon->groupname))) |
| 231 | baduser = daemon->groupname; |
| 232 | |
| 233 | if (baduser) |
| 234 | die(_("unknown user or group: %s"), baduser, EC_BADCONF); |
| 235 | |
| 236 | /* implement group defaults, "dip" if available, or group associated with uid */ |
| 237 | if (!daemon->group_set && !gp) |
| 238 | { |
| 239 | if (!(gp = getgrnam(CHGRP)) && ent_pw) |
| 240 | gp = getgrgid(ent_pw->pw_gid); |
| 241 | |
| 242 | /* for error message */ |
| 243 | if (gp) |
| 244 | daemon->groupname = gp->gr_name; |
| 245 | } |
| 246 | |
| 247 | #if defined(HAVE_LINUX_NETWORK) |
| 248 | /* determine capability API version here, while we can still |
| 249 | call safe_malloc */ |
| 250 | if (ent_pw && ent_pw->pw_uid != 0) |
| 251 | { |
| 252 | int capsize = 1; /* for header version 1 */ |
| 253 | hdr = safe_malloc(sizeof(*hdr)); |
| 254 | |
| 255 | /* find version supported by kernel */ |
| 256 | memset(hdr, 0, sizeof(*hdr)); |
| 257 | capget(hdr, NULL); |
| 258 | |
| 259 | if (hdr->version != LINUX_CAPABILITY_VERSION_1) |
| 260 | { |
| 261 | /* if unknown version, use largest supported version (3) */ |
| 262 | if (hdr->version != LINUX_CAPABILITY_VERSION_2) |
| 263 | hdr->version = LINUX_CAPABILITY_VERSION_3; |
| 264 | capsize = 2; |
| 265 | } |
| 266 | |
| 267 | data = safe_malloc(sizeof(*data) * capsize); |
| 268 | memset(data, 0, sizeof(*data) * capsize); |
| 269 | } |
| 270 | #endif |
| 271 | |
| 272 | /* Use a pipe to carry signals and other events back to the event loop |
| 273 | in a race-free manner and another to carry errors to daemon-invoking process */ |
| 274 | safe_pipe(pipefd, 1); |
| 275 | |
| 276 | piperead = pipefd[0]; |
| 277 | pipewrite = pipefd[1]; |
| 278 | /* prime the pipe to load stuff first time. */ |
| 279 | send_event(pipewrite, EVENT_RELOAD, 0); |
| 280 | |
| 281 | err_pipe[1] = -1; |
| 282 | |
| 283 | if (!(daemon->options & OPT_DEBUG)) |
| 284 | { |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 285 | #ifndef __ANDROID__ |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 286 | int nullfd; |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 287 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 288 | |
| 289 | /* The following code "daemonizes" the process. |
| 290 | See Stevens section 12.4 */ |
| 291 | |
| 292 | if (chdir("/") != 0) |
| 293 | die(_("cannot chdir to filesystem root: %s"), NULL, EC_MISC); |
| 294 | |
| 295 | #ifndef NO_FORK |
| 296 | if (!(daemon->options & OPT_NO_FORK)) |
| 297 | { |
| 298 | pid_t pid; |
| 299 | |
| 300 | /* pipe to carry errors back to original process. |
| 301 | When startup is complete we close this and the process terminates. */ |
| 302 | safe_pipe(err_pipe, 0); |
| 303 | |
| 304 | if ((pid = fork()) == -1) |
| 305 | /* fd == -1 since we've not forked, never returns. */ |
| 306 | send_event(-1, EVENT_FORK_ERR, errno); |
| 307 | |
| 308 | if (pid != 0) |
| 309 | { |
| 310 | struct event_desc ev; |
| 311 | |
| 312 | /* close our copy of write-end */ |
| 313 | close(err_pipe[1]); |
| 314 | |
| 315 | /* check for errors after the fork */ |
| 316 | if (read_write(err_pipe[0], (unsigned char *)&ev, sizeof(ev), 1)) |
| 317 | fatal_event(&ev); |
| 318 | |
| 319 | _exit(EC_GOOD); |
| 320 | } |
| 321 | |
| 322 | close(err_pipe[0]); |
| 323 | |
| 324 | /* NO calls to die() from here on. */ |
| 325 | |
| 326 | setsid(); |
| 327 | |
| 328 | if ((pid = fork()) == -1) |
| 329 | send_event(err_pipe[1], EVENT_FORK_ERR, errno); |
| 330 | |
| 331 | if (pid != 0) |
| 332 | _exit(0); |
| 333 | } |
| 334 | #endif |
| 335 | |
| 336 | /* write pidfile _after_ forking ! */ |
| 337 | if (daemon->runfile) |
| 338 | { |
| 339 | FILE *pidfile; |
| 340 | |
| 341 | /* only complain if started as root */ |
| 342 | if ((pidfile = fopen(daemon->runfile, "w"))) |
| 343 | { |
| 344 | fprintf(pidfile, "%d\n", (int) getpid()); |
| 345 | fclose(pidfile); |
| 346 | } |
| 347 | else if (getuid() == 0) |
| 348 | { |
| 349 | send_event(err_pipe[1], EVENT_PIDFILE, errno); |
| 350 | _exit(0); |
| 351 | } |
| 352 | } |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 353 | |
| 354 | #ifndef __ANDROID__ |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 355 | /* open stdout etc to /dev/null */ |
| 356 | nullfd = open("/dev/null", O_RDWR); |
| 357 | dup2(nullfd, STDOUT_FILENO); |
| 358 | dup2(nullfd, STDERR_FILENO); |
| 359 | dup2(nullfd, STDIN_FILENO); |
| 360 | close(nullfd); |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 361 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 362 | } |
| 363 | |
| 364 | log_err = log_start(ent_pw, err_pipe[1]); |
| 365 | |
| 366 | /* if we are to run scripts, we need to fork a helper before dropping root. */ |
| 367 | daemon->helperfd = -1; |
| 368 | #if defined(HAVE_DHCP) && defined(HAVE_SCRIPT) |
| 369 | if (daemon->dhcp && daemon->lease_change_command) |
| 370 | daemon->helperfd = create_helper(pipewrite, err_pipe[1], script_uid, script_gid, max_fd); |
| 371 | #endif |
| 372 | |
| 373 | if (!(daemon->options & OPT_DEBUG) && getuid() == 0) |
| 374 | { |
| 375 | int bad_capabilities = 0; |
| 376 | gid_t dummy; |
| 377 | |
| 378 | /* remove all supplimentary groups */ |
| 379 | if (gp && |
| 380 | (setgroups(0, &dummy) == -1 || |
| 381 | setgid(gp->gr_gid) == -1)) |
| 382 | { |
| 383 | send_event(err_pipe[1], EVENT_GROUP_ERR, errno); |
| 384 | _exit(0); |
| 385 | } |
| 386 | |
| 387 | if (ent_pw && ent_pw->pw_uid != 0) |
| 388 | { |
| 389 | #if defined(HAVE_LINUX_NETWORK) |
| 390 | /* On linux, we keep CAP_NETADMIN (for ARP-injection) and |
| 391 | CAP_NET_RAW (for icmp) if we're doing dhcp */ |
| 392 | data->effective = data->permitted = data->inheritable = |
Robert Greenwalt | 41cd7ed | 2012-12-11 12:42:32 -0800 | [diff] [blame] | 393 | #ifdef __ANDROID__ |
| 394 | (1 << CAP_NET_BIND_SERVICE) | |
| 395 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 396 | (1 << CAP_NET_ADMIN) | (1 << CAP_NET_RAW) | (1 << CAP_SETUID); |
| 397 | |
| 398 | /* Tell kernel to not clear capabilities when dropping root */ |
San Mehat | 5658bcb | 2010-01-20 10:16:30 -0800 | [diff] [blame] | 399 | if (capset(hdr, data) == -1 || prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 400 | bad_capabilities = errno; |
| 401 | |
| 402 | #elif defined(HAVE_SOLARIS_NETWORK) |
| 403 | /* http://developers.sun.com/solaris/articles/program_privileges.html */ |
| 404 | priv_set_t *priv_set; |
| 405 | |
| 406 | if (!(priv_set = priv_str_to_set("basic", ",", NULL)) || |
| 407 | priv_addset(priv_set, PRIV_NET_ICMPACCESS) == -1 || |
| 408 | priv_addset(priv_set, PRIV_SYS_NET_CONFIG) == -1) |
| 409 | bad_capabilities = errno; |
| 410 | |
| 411 | if (priv_set && bad_capabilities == 0) |
| 412 | { |
| 413 | priv_inverse(priv_set); |
| 414 | |
| 415 | if (setppriv(PRIV_OFF, PRIV_LIMIT, priv_set) == -1) |
| 416 | bad_capabilities = errno; |
| 417 | } |
| 418 | |
| 419 | if (priv_set) |
| 420 | priv_freeset(priv_set); |
| 421 | |
| 422 | #endif |
| 423 | |
| 424 | if (bad_capabilities != 0) |
| 425 | { |
| 426 | send_event(err_pipe[1], EVENT_CAP_ERR, bad_capabilities); |
| 427 | _exit(0); |
| 428 | } |
| 429 | |
| 430 | /* finally drop root */ |
| 431 | if (setuid(ent_pw->pw_uid) == -1) |
| 432 | { |
| 433 | send_event(err_pipe[1], EVENT_USER_ERR, errno); |
| 434 | _exit(0); |
| 435 | } |
| 436 | |
| 437 | #ifdef HAVE_LINUX_NETWORK |
| 438 | data->effective = data->permitted = |
Robert Greenwalt | 41cd7ed | 2012-12-11 12:42:32 -0800 | [diff] [blame] | 439 | #ifdef __ANDROID__ |
| 440 | (1 << CAP_NET_BIND_SERVICE) | |
| 441 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 442 | (1 << CAP_NET_ADMIN) | (1 << CAP_NET_RAW); |
| 443 | data->inheritable = 0; |
| 444 | |
| 445 | /* lose the setuid and setgid capbilities */ |
| 446 | if (capset(hdr, data) == -1) |
| 447 | { |
| 448 | send_event(err_pipe[1], EVENT_CAP_ERR, errno); |
| 449 | _exit(0); |
| 450 | } |
| 451 | #endif |
| 452 | |
| 453 | } |
| 454 | } |
| 455 | |
| 456 | #ifdef HAVE_LINUX_NETWORK |
| 457 | if (daemon->options & OPT_DEBUG) |
San Mehat | 5658bcb | 2010-01-20 10:16:30 -0800 | [diff] [blame] | 458 | prctl(PR_SET_DUMPABLE, 1, 0, 0, 0); |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 459 | #endif |
| 460 | |
| 461 | if (daemon->port == 0) |
| 462 | my_syslog(LOG_INFO, _("started, version %s DNS disabled"), VERSION); |
| 463 | else if (daemon->cachesize != 0) |
| 464 | my_syslog(LOG_INFO, _("started, version %s cachesize %d"), VERSION, daemon->cachesize); |
| 465 | else |
| 466 | my_syslog(LOG_INFO, _("started, version %s cache disabled"), VERSION); |
| 467 | |
| 468 | my_syslog(LOG_INFO, _("compile time options: %s"), compile_opts); |
| 469 | |
| 470 | #ifdef HAVE_DBUS |
| 471 | if (daemon->options & OPT_DBUS) |
| 472 | { |
| 473 | if (daemon->dbus) |
| 474 | my_syslog(LOG_INFO, _("DBus support enabled: connected to system bus")); |
| 475 | else |
| 476 | my_syslog(LOG_INFO, _("DBus support enabled: bus connection pending")); |
| 477 | } |
| 478 | #endif |
| 479 | |
| 480 | if (log_err != 0) |
| 481 | my_syslog(LOG_WARNING, _("warning: failed to change owner of %s: %s"), |
| 482 | daemon->log_file, strerror(log_err)); |
| 483 | |
| 484 | if (bind_fallback) |
| 485 | my_syslog(LOG_WARNING, _("setting --bind-interfaces option because of OS limitations")); |
| 486 | |
| 487 | if (!(daemon->options & OPT_NOWILD)) |
| 488 | for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next) |
| 489 | if (if_tmp->name && !if_tmp->used) |
| 490 | my_syslog(LOG_WARNING, _("warning: interface %s does not currently exist"), if_tmp->name); |
| 491 | |
| 492 | if (daemon->port != 0 && (daemon->options & OPT_NO_RESOLV)) |
| 493 | { |
| 494 | if (daemon->resolv_files && !daemon->resolv_files->is_default) |
| 495 | my_syslog(LOG_WARNING, _("warning: ignoring resolv-file flag because no-resolv is set")); |
| 496 | daemon->resolv_files = NULL; |
| 497 | if (!daemon->servers) |
| 498 | my_syslog(LOG_WARNING, _("warning: no upstream servers configured")); |
| 499 | } |
| 500 | |
| 501 | if (daemon->max_logs != 0) |
| 502 | my_syslog(LOG_INFO, _("asynchronous logging enabled, queue limit is %d messages"), daemon->max_logs); |
| 503 | |
| 504 | #ifdef HAVE_DHCP |
| 505 | if (daemon->dhcp) |
| 506 | { |
| 507 | struct dhcp_context *dhcp_tmp; |
| 508 | |
| 509 | for (dhcp_tmp = daemon->dhcp; dhcp_tmp; dhcp_tmp = dhcp_tmp->next) |
| 510 | { |
| 511 | prettyprint_time(daemon->dhcp_buff2, dhcp_tmp->lease_time); |
| 512 | strcpy(daemon->dhcp_buff, inet_ntoa(dhcp_tmp->start)); |
| 513 | my_syslog(MS_DHCP | LOG_INFO, |
| 514 | (dhcp_tmp->flags & CONTEXT_STATIC) ? |
| 515 | _("DHCP, static leases only on %.0s%s, lease time %s") : |
| 516 | (dhcp_tmp->flags & CONTEXT_PROXY) ? |
| 517 | _("DHCP, proxy on subnet %.0s%s%.0s") : |
| 518 | _("DHCP, IP range %s -- %s, lease time %s"), |
| 519 | daemon->dhcp_buff, inet_ntoa(dhcp_tmp->end), daemon->dhcp_buff2); |
| 520 | } |
| 521 | } |
| 522 | #endif |
| 523 | |
| 524 | #ifdef HAVE_TFTP |
| 525 | if (daemon->options & OPT_TFTP) |
| 526 | { |
| 527 | #ifdef FD_SETSIZE |
| 528 | if (FD_SETSIZE < (unsigned)max_fd) |
| 529 | max_fd = FD_SETSIZE; |
| 530 | #endif |
| 531 | |
| 532 | my_syslog(MS_TFTP | LOG_INFO, "TFTP %s%s %s", |
| 533 | daemon->tftp_prefix ? _("root is ") : _("enabled"), |
| 534 | daemon->tftp_prefix ? daemon->tftp_prefix: "", |
| 535 | daemon->options & OPT_TFTP_SECURE ? _("secure mode") : ""); |
| 536 | |
| 537 | /* This is a guess, it assumes that for small limits, |
| 538 | disjoint files might be served, but for large limits, |
| 539 | a single file will be sent to may clients (the file only needs |
| 540 | one fd). */ |
| 541 | |
| 542 | max_fd -= 30; /* use other than TFTP */ |
| 543 | |
| 544 | if (max_fd < 0) |
| 545 | max_fd = 5; |
| 546 | else if (max_fd < 100) |
| 547 | max_fd = max_fd/2; |
| 548 | else |
| 549 | max_fd = max_fd - 20; |
| 550 | |
| 551 | /* if we have to use a limited range of ports, |
| 552 | that will limit the number of transfers */ |
| 553 | if (daemon->start_tftp_port != 0 && |
| 554 | daemon->end_tftp_port - daemon->start_tftp_port + 1 < max_fd) |
| 555 | max_fd = daemon->end_tftp_port - daemon->start_tftp_port + 1; |
| 556 | |
| 557 | if (daemon->tftp_max > max_fd) |
| 558 | { |
| 559 | daemon->tftp_max = max_fd; |
| 560 | my_syslog(MS_TFTP | LOG_WARNING, |
| 561 | _("restricting maximum simultaneous TFTP transfers to %d"), |
| 562 | daemon->tftp_max); |
| 563 | } |
| 564 | } |
| 565 | #endif |
| 566 | |
| 567 | /* finished start-up - release original process */ |
| 568 | if (err_pipe[1] != -1) |
| 569 | close(err_pipe[1]); |
| 570 | |
| 571 | if (daemon->port != 0) |
| 572 | check_servers(); |
| 573 | |
| 574 | pid = getpid(); |
| 575 | |
| 576 | while (1) |
| 577 | { |
| 578 | int maxfd = -1; |
| 579 | struct timeval t, *tp = NULL; |
| 580 | fd_set rset, wset, eset; |
| 581 | |
| 582 | FD_ZERO(&rset); |
| 583 | FD_ZERO(&wset); |
| 584 | FD_ZERO(&eset); |
| 585 | |
| 586 | /* if we are out of resources, find how long we have to wait |
| 587 | for some to come free, we'll loop around then and restart |
| 588 | listening for queries */ |
| 589 | if ((t.tv_sec = set_dns_listeners(now, &rset, &maxfd)) != 0) |
| 590 | { |
| 591 | t.tv_usec = 0; |
| 592 | tp = &t; |
| 593 | } |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 594 | #ifdef __ANDROID__ |
| 595 | set_android_listeners(&rset, &maxfd); |
| 596 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 597 | |
| 598 | /* Whilst polling for the dbus, or doing a tftp transfer, wake every quarter second */ |
| 599 | if (daemon->tftp_trans || |
| 600 | ((daemon->options & OPT_DBUS) && !daemon->dbus)) |
| 601 | { |
| 602 | t.tv_sec = 0; |
| 603 | t.tv_usec = 250000; |
| 604 | tp = &t; |
| 605 | } |
| 606 | |
| 607 | #ifdef HAVE_DBUS |
| 608 | set_dbus_listeners(&maxfd, &rset, &wset, &eset); |
| 609 | #endif |
| 610 | |
| 611 | #ifdef HAVE_DHCP |
| 612 | if (daemon->dhcp) |
| 613 | { |
| 614 | FD_SET(daemon->dhcpfd, &rset); |
| 615 | bump_maxfd(daemon->dhcpfd, &maxfd); |
| 616 | } |
| 617 | #endif |
| 618 | |
| 619 | #ifdef HAVE_LINUX_NETWORK |
| 620 | FD_SET(daemon->netlinkfd, &rset); |
| 621 | bump_maxfd(daemon->netlinkfd, &maxfd); |
| 622 | #endif |
| 623 | |
| 624 | FD_SET(piperead, &rset); |
| 625 | bump_maxfd(piperead, &maxfd); |
| 626 | |
| 627 | #ifdef HAVE_DHCP |
| 628 | # ifdef HAVE_SCRIPT |
| 629 | while (helper_buf_empty() && do_script_run(now)); |
| 630 | |
| 631 | if (!helper_buf_empty()) |
| 632 | { |
| 633 | FD_SET(daemon->helperfd, &wset); |
| 634 | bump_maxfd(daemon->helperfd, &maxfd); |
| 635 | } |
| 636 | # else |
| 637 | /* need this for other side-effects */ |
| 638 | while (do_script_run(now)); |
| 639 | # endif |
| 640 | #endif |
| 641 | |
| 642 | /* must do this just before select(), when we know no |
| 643 | more calls to my_syslog() can occur */ |
| 644 | set_log_writer(&wset, &maxfd); |
| 645 | |
| 646 | if (select(maxfd+1, &rset, &wset, &eset, tp) < 0) |
| 647 | { |
| 648 | /* otherwise undefined after error */ |
| 649 | FD_ZERO(&rset); FD_ZERO(&wset); FD_ZERO(&eset); |
| 650 | } |
| 651 | |
| 652 | now = dnsmasq_time(); |
| 653 | |
| 654 | check_log_writer(&wset); |
| 655 | |
| 656 | /* Check for changes to resolv files once per second max. */ |
| 657 | /* Don't go silent for long periods if the clock goes backwards. */ |
| 658 | if (daemon->last_resolv == 0 || |
| 659 | difftime(now, daemon->last_resolv) > 1.0 || |
| 660 | difftime(now, daemon->last_resolv) < -1.0) |
| 661 | { |
| 662 | daemon->last_resolv = now; |
| 663 | |
| 664 | if (daemon->port != 0 && !(daemon->options & OPT_NO_POLL)) |
| 665 | poll_resolv(); |
| 666 | } |
| 667 | |
| 668 | if (FD_ISSET(piperead, &rset)) |
| 669 | async_event(piperead, now); |
| 670 | |
| 671 | #ifdef HAVE_LINUX_NETWORK |
| 672 | if (FD_ISSET(daemon->netlinkfd, &rset)) |
| 673 | netlink_multicast(); |
| 674 | #endif |
| 675 | |
| 676 | #ifdef HAVE_DBUS |
| 677 | /* if we didn't create a DBus connection, retry now. */ |
| 678 | if ((daemon->options & OPT_DBUS) && !daemon->dbus) |
| 679 | { |
| 680 | char *err; |
| 681 | if ((err = dbus_init())) |
| 682 | my_syslog(LOG_WARNING, _("DBus error: %s"), err); |
| 683 | if (daemon->dbus) |
| 684 | my_syslog(LOG_INFO, _("connected to system DBus")); |
| 685 | } |
| 686 | check_dbus_listeners(&rset, &wset, &eset); |
| 687 | #endif |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 688 | |
| 689 | #ifdef __ANDROID__ |
| 690 | check_android_listeners(&rset); |
| 691 | #endif |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 692 | |
| 693 | check_dns_listeners(&rset, now); |
| 694 | |
| 695 | #ifdef HAVE_TFTP |
| 696 | check_tftp_listeners(&rset, now); |
| 697 | #endif |
| 698 | |
| 699 | #ifdef HAVE_DHCP |
| 700 | if (daemon->dhcp && FD_ISSET(daemon->dhcpfd, &rset)) |
| 701 | dhcp_packet(now); |
| 702 | |
| 703 | # ifdef HAVE_SCRIPT |
| 704 | if (daemon->helperfd != -1 && FD_ISSET(daemon->helperfd, &wset)) |
| 705 | helper_write(); |
| 706 | # endif |
| 707 | #endif |
| 708 | |
| 709 | } |
| 710 | } |
| 711 | |
| 712 | static void sig_handler(int sig) |
| 713 | { |
| 714 | if (pid == 0) |
| 715 | { |
| 716 | /* ignore anything other than TERM during startup |
| 717 | and in helper proc. (helper ignore TERM too) */ |
| 718 | if (sig == SIGTERM) |
| 719 | exit(EC_MISC); |
| 720 | } |
| 721 | else if (pid != getpid()) |
| 722 | { |
| 723 | /* alarm is used to kill TCP children after a fixed time. */ |
| 724 | if (sig == SIGALRM) |
| 725 | _exit(0); |
| 726 | } |
| 727 | else |
| 728 | { |
| 729 | /* master process */ |
| 730 | int event, errsave = errno; |
| 731 | |
| 732 | if (sig == SIGHUP) |
| 733 | event = EVENT_RELOAD; |
| 734 | else if (sig == SIGCHLD) |
| 735 | event = EVENT_CHILD; |
| 736 | else if (sig == SIGALRM) |
| 737 | event = EVENT_ALARM; |
| 738 | else if (sig == SIGTERM) |
| 739 | event = EVENT_TERM; |
| 740 | else if (sig == SIGUSR1) |
| 741 | event = EVENT_DUMP; |
| 742 | else if (sig == SIGUSR2) |
| 743 | event = EVENT_REOPEN; |
| 744 | else |
| 745 | return; |
| 746 | |
| 747 | send_event(pipewrite, event, 0); |
| 748 | errno = errsave; |
| 749 | } |
| 750 | } |
| 751 | |
| 752 | void send_event(int fd, int event, int data) |
| 753 | { |
| 754 | struct event_desc ev; |
| 755 | |
| 756 | ev.event = event; |
| 757 | ev.data = data; |
| 758 | |
| 759 | /* error pipe, debug mode. */ |
| 760 | if (fd == -1) |
| 761 | fatal_event(&ev); |
| 762 | else |
| 763 | /* pipe is non-blocking and struct event_desc is smaller than |
| 764 | PIPE_BUF, so this either fails or writes everything */ |
| 765 | while (write(fd, &ev, sizeof(ev)) == -1 && errno == EINTR); |
| 766 | } |
| 767 | |
| 768 | static void fatal_event(struct event_desc *ev) |
| 769 | { |
| 770 | errno = ev->data; |
| 771 | |
| 772 | switch (ev->event) |
| 773 | { |
| 774 | case EVENT_DIE: |
| 775 | exit(0); |
| 776 | |
| 777 | case EVENT_FORK_ERR: |
| 778 | die(_("cannot fork into background: %s"), NULL, EC_MISC); |
| 779 | |
| 780 | case EVENT_PIPE_ERR: |
| 781 | die(_("failed to create helper: %s"), NULL, EC_MISC); |
| 782 | |
| 783 | case EVENT_CAP_ERR: |
| 784 | die(_("setting capabilities failed: %s"), NULL, EC_MISC); |
| 785 | |
| 786 | case EVENT_USER_ERR: |
| 787 | case EVENT_HUSER_ERR: |
| 788 | die(_("failed to change user-id to %s: %s"), |
| 789 | ev->event == EVENT_USER_ERR ? daemon->username : daemon->scriptuser, |
| 790 | EC_MISC); |
| 791 | |
| 792 | case EVENT_GROUP_ERR: |
| 793 | die(_("failed to change group-id to %s: %s"), daemon->groupname, EC_MISC); |
| 794 | |
| 795 | case EVENT_PIDFILE: |
| 796 | die(_("failed to open pidfile %s: %s"), daemon->runfile, EC_FILE); |
| 797 | |
| 798 | case EVENT_LOG_ERR: |
| 799 | die(_("cannot open %s: %s"), daemon->log_file ? daemon->log_file : "log", EC_FILE); |
| 800 | } |
| 801 | } |
| 802 | |
| 803 | static void async_event(int pipe, time_t now) |
| 804 | { |
| 805 | pid_t p; |
| 806 | struct event_desc ev; |
| 807 | int i; |
| 808 | |
| 809 | if (read_write(pipe, (unsigned char *)&ev, sizeof(ev), 1)) |
| 810 | switch (ev.event) |
| 811 | { |
| 812 | case EVENT_RELOAD: |
| 813 | clear_cache_and_reload(now); |
| 814 | if (daemon->port != 0 && daemon->resolv_files && (daemon->options & OPT_NO_POLL)) |
| 815 | { |
| 816 | reload_servers(daemon->resolv_files->name); |
| 817 | check_servers(); |
| 818 | } |
| 819 | #ifdef HAVE_DHCP |
| 820 | rerun_scripts(); |
| 821 | #endif |
| 822 | break; |
| 823 | |
| 824 | case EVENT_DUMP: |
| 825 | if (daemon->port != 0) |
| 826 | dump_cache(now); |
| 827 | break; |
| 828 | |
| 829 | case EVENT_ALARM: |
| 830 | #ifdef HAVE_DHCP |
| 831 | if (daemon->dhcp) |
| 832 | { |
| 833 | lease_prune(NULL, now); |
| 834 | lease_update_file(now); |
| 835 | } |
| 836 | #endif |
| 837 | break; |
| 838 | |
| 839 | case EVENT_CHILD: |
| 840 | /* See Stevens 5.10 */ |
| 841 | while ((p = waitpid(-1, NULL, WNOHANG)) != 0) |
| 842 | if (p == -1) |
| 843 | { |
| 844 | if (errno != EINTR) |
| 845 | break; |
| 846 | } |
| 847 | else |
| 848 | for (i = 0 ; i < MAX_PROCS; i++) |
| 849 | if (daemon->tcp_pids[i] == p) |
| 850 | daemon->tcp_pids[i] = 0; |
| 851 | break; |
| 852 | |
| 853 | case EVENT_KILLED: |
| 854 | my_syslog(LOG_WARNING, _("child process killed by signal %d"), ev.data); |
| 855 | break; |
| 856 | |
| 857 | case EVENT_EXITED: |
| 858 | my_syslog(LOG_WARNING, _("child process exited with status %d"), ev.data); |
| 859 | break; |
| 860 | |
| 861 | case EVENT_EXEC_ERR: |
| 862 | my_syslog(LOG_ERR, _("failed to execute %s: %s"), |
| 863 | daemon->lease_change_command, strerror(ev.data)); |
| 864 | break; |
| 865 | |
| 866 | /* necessary for fatal errors in helper */ |
| 867 | case EVENT_HUSER_ERR: |
| 868 | case EVENT_DIE: |
| 869 | fatal_event(&ev); |
| 870 | break; |
| 871 | |
| 872 | case EVENT_REOPEN: |
| 873 | /* Note: this may leave TCP-handling processes with the old file still open. |
| 874 | Since any such process will die in CHILD_LIFETIME or probably much sooner, |
| 875 | we leave them logging to the old file. */ |
| 876 | if (daemon->log_file != NULL) |
| 877 | log_reopen(daemon->log_file); |
| 878 | break; |
| 879 | |
| 880 | case EVENT_TERM: |
| 881 | /* Knock all our children on the head. */ |
| 882 | for (i = 0; i < MAX_PROCS; i++) |
| 883 | if (daemon->tcp_pids[i] != 0) |
| 884 | kill(daemon->tcp_pids[i], SIGALRM); |
| 885 | |
| 886 | #if defined(HAVE_DHCP) && defined(HAVE_SCRIPT) |
| 887 | /* handle pending lease transitions */ |
| 888 | if (daemon->helperfd != -1) |
| 889 | { |
| 890 | /* block in writes until all done */ |
| 891 | if ((i = fcntl(daemon->helperfd, F_GETFL)) != -1) |
| 892 | fcntl(daemon->helperfd, F_SETFL, i & ~O_NONBLOCK); |
| 893 | do { |
| 894 | helper_write(); |
| 895 | } while (!helper_buf_empty() || do_script_run(now)); |
| 896 | close(daemon->helperfd); |
| 897 | } |
| 898 | #endif |
| 899 | |
| 900 | if (daemon->lease_stream) |
| 901 | fclose(daemon->lease_stream); |
| 902 | |
| 903 | if (daemon->runfile) |
| 904 | unlink(daemon->runfile); |
| 905 | |
| 906 | my_syslog(LOG_INFO, _("exiting on receipt of SIGTERM")); |
| 907 | flush_log(); |
| 908 | exit(EC_GOOD); |
| 909 | } |
| 910 | } |
| 911 | |
| 912 | static void poll_resolv() |
| 913 | { |
| 914 | struct resolvc *res, *latest; |
| 915 | struct stat statbuf; |
| 916 | time_t last_change = 0; |
| 917 | /* There may be more than one possible file. |
| 918 | Go through and find the one which changed _last_. |
| 919 | Warn of any which can't be read. */ |
| 920 | for (latest = NULL, res = daemon->resolv_files; res; res = res->next) |
| 921 | if (stat(res->name, &statbuf) == -1) |
| 922 | { |
| 923 | if (!res->logged) |
| 924 | my_syslog(LOG_WARNING, _("failed to access %s: %s"), res->name, strerror(errno)); |
| 925 | res->logged = 1; |
| 926 | } |
| 927 | else |
| 928 | { |
| 929 | res->logged = 0; |
| 930 | if (statbuf.st_mtime != res->mtime) |
| 931 | { |
| 932 | res->mtime = statbuf.st_mtime; |
| 933 | if (difftime(statbuf.st_mtime, last_change) > 0.0) |
| 934 | { |
| 935 | last_change = statbuf.st_mtime; |
| 936 | latest = res; |
| 937 | } |
| 938 | } |
| 939 | } |
| 940 | |
| 941 | if (latest) |
| 942 | { |
| 943 | static int warned = 0; |
| 944 | if (reload_servers(latest->name)) |
| 945 | { |
| 946 | my_syslog(LOG_INFO, _("reading %s"), latest->name); |
| 947 | warned = 0; |
| 948 | check_servers(); |
| 949 | if (daemon->options & OPT_RELOAD) |
| 950 | cache_reload(); |
| 951 | } |
| 952 | else |
| 953 | { |
| 954 | latest->mtime = 0; |
| 955 | if (!warned) |
| 956 | { |
| 957 | my_syslog(LOG_WARNING, _("no servers found in %s, will retry"), latest->name); |
| 958 | warned = 1; |
| 959 | } |
| 960 | } |
| 961 | } |
| 962 | } |
| 963 | |
| 964 | void clear_cache_and_reload(time_t now) |
| 965 | { |
| 966 | if (daemon->port != 0) |
| 967 | cache_reload(); |
| 968 | |
| 969 | #ifdef HAVE_DHCP |
| 970 | if (daemon->dhcp) |
| 971 | { |
| 972 | if (daemon->options & OPT_ETHERS) |
| 973 | dhcp_read_ethers(); |
| 974 | reread_dhcp(); |
| 975 | dhcp_update_configs(daemon->dhcp_conf); |
| 976 | check_dhcp_hosts(0); |
| 977 | lease_update_from_configs(); |
| 978 | lease_update_file(now); |
| 979 | lease_update_dns(); |
| 980 | } |
| 981 | #endif |
| 982 | } |
| 983 | |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 984 | #ifdef __ANDROID__ |
| 985 | |
| 986 | static int set_android_listeners(fd_set *set, int *maxfdp) { |
| 987 | FD_SET(STDIN_FILENO, set); |
| 988 | bump_maxfd(STDIN_FILENO, maxfdp); |
| 989 | return 0; |
| 990 | } |
| 991 | |
| 992 | static int check_android_listeners(fd_set *set) { |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 993 | int retcode = 0; |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 994 | if (FD_ISSET(STDIN_FILENO, set)) { |
| 995 | char buffer[1024]; |
| 996 | int rc; |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 997 | int consumed = 0; |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 998 | |
| 999 | if ((rc = read(STDIN_FILENO, buffer, sizeof(buffer) -1)) < 0) { |
| 1000 | my_syslog(LOG_ERR, _("Error reading from stdin (%s)"), strerror(errno)); |
| 1001 | return -1; |
| 1002 | } |
| 1003 | buffer[rc] = '\0'; |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 1004 | while(consumed < rc) { |
| 1005 | char *cmd; |
| 1006 | char *current_cmd = &buffer[consumed]; |
| 1007 | char *params = current_cmd; |
| 1008 | int len = strlen(current_cmd); |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 1009 | |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 1010 | cmd = strsep(¶ms, ":"); |
| 1011 | if (!strcmp(cmd, "update_dns")) { |
| 1012 | if (params != NULL) { |
| 1013 | set_servers(params); |
| 1014 | check_servers(); |
| 1015 | } else { |
| 1016 | my_syslog(LOG_ERR, _("Malformatted msg '%s'"), current_cmd); |
| 1017 | retcode = -1; |
| 1018 | } |
Robert Greenwalt | 41cd7ed | 2012-12-11 12:42:32 -0800 | [diff] [blame] | 1019 | } else if (!strcmp(cmd, "update_ifaces")) { |
| 1020 | if (params != NULL) { |
| 1021 | set_interfaces(params); |
| 1022 | } else { |
| 1023 | my_syslog(LOG_ERR, _("Malformatted msg '%s'"), current_cmd); |
| 1024 | retcode = -1; |
| 1025 | } |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 1026 | } else { |
| 1027 | my_syslog(LOG_ERR, _("Unknown cmd '%s'"), cmd); |
| 1028 | retcode = -1; |
| 1029 | } |
| 1030 | consumed += len + 1; |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 1031 | } |
| 1032 | } |
Pierre Crépieux | 00b7b35 | 2012-05-04 16:12:17 +0200 | [diff] [blame] | 1033 | return retcode; |
San Mehat | 33b3444 | 2010-01-20 10:54:48 -0800 | [diff] [blame] | 1034 | } |
| 1035 | #endif |
| 1036 | |
San Mehat | ffd6872 | 2010-01-20 09:56:15 -0800 | [diff] [blame] | 1037 | static int set_dns_listeners(time_t now, fd_set *set, int *maxfdp) |
| 1038 | { |
| 1039 | struct serverfd *serverfdp; |
| 1040 | struct listener *listener; |
| 1041 | int wait = 0, i; |
| 1042 | |
| 1043 | #ifdef HAVE_TFTP |
| 1044 | int tftp = 0; |
| 1045 | struct tftp_transfer *transfer; |
| 1046 | for (transfer = daemon->tftp_trans; transfer; transfer = transfer->next) |
| 1047 | { |
| 1048 | tftp++; |
| 1049 | FD_SET(transfer->sockfd, set); |
| 1050 | bump_maxfd(transfer->sockfd, maxfdp); |
| 1051 | } |
| 1052 | #endif |
| 1053 | |
| 1054 | /* will we be able to get memory? */ |
| 1055 | if (daemon->port != 0) |
| 1056 | get_new_frec(now, &wait); |
| 1057 | |
| 1058 | for (serverfdp = daemon->sfds; serverfdp; serverfdp = serverfdp->next) |
| 1059 | { |
| 1060 | FD_SET(serverfdp->fd, set); |
| 1061 | bump_maxfd(serverfdp->fd, maxfdp); |
| 1062 | } |
| 1063 | |
| 1064 | if (daemon->port != 0 && !daemon->osport) |
| 1065 | for (i = 0; i < RANDOM_SOCKS; i++) |
| 1066 | if (daemon->randomsocks[i].refcount != 0) |
| 1067 | { |
| 1068 | FD_SET(daemon->randomsocks[i].fd, set); |
| 1069 | bump_maxfd(daemon->randomsocks[i].fd, maxfdp); |
| 1070 | } |
| 1071 | |
| 1072 | for (listener = daemon->listeners; listener; listener = listener->next) |
| 1073 | { |
| 1074 | /* only listen for queries if we have resources */ |
| 1075 | if (listener->fd != -1 && wait == 0) |
| 1076 | { |
| 1077 | FD_SET(listener->fd, set); |
| 1078 | bump_maxfd(listener->fd, maxfdp); |
| 1079 | } |
| 1080 | |
| 1081 | /* death of a child goes through the select loop, so |
| 1082 | we don't need to explicitly arrange to wake up here */ |
| 1083 | if (listener->tcpfd != -1) |
| 1084 | for (i = 0; i < MAX_PROCS; i++) |
| 1085 | if (daemon->tcp_pids[i] == 0) |
| 1086 | { |
| 1087 | FD_SET(listener->tcpfd, set); |
| 1088 | bump_maxfd(listener->tcpfd, maxfdp); |
| 1089 | break; |
| 1090 | } |
| 1091 | |
| 1092 | #ifdef HAVE_TFTP |
| 1093 | if (tftp <= daemon->tftp_max && listener->tftpfd != -1) |
| 1094 | { |
| 1095 | FD_SET(listener->tftpfd, set); |
| 1096 | bump_maxfd(listener->tftpfd, maxfdp); |
| 1097 | } |
| 1098 | #endif |
| 1099 | |
| 1100 | } |
| 1101 | |
| 1102 | return wait; |
| 1103 | } |
| 1104 | |
| 1105 | static void check_dns_listeners(fd_set *set, time_t now) |
| 1106 | { |
| 1107 | struct serverfd *serverfdp; |
| 1108 | struct listener *listener; |
| 1109 | int i; |
| 1110 | |
| 1111 | for (serverfdp = daemon->sfds; serverfdp; serverfdp = serverfdp->next) |
| 1112 | if (FD_ISSET(serverfdp->fd, set)) |
| 1113 | reply_query(serverfdp->fd, serverfdp->source_addr.sa.sa_family, now); |
| 1114 | |
| 1115 | if (daemon->port != 0 && !daemon->osport) |
| 1116 | for (i = 0; i < RANDOM_SOCKS; i++) |
| 1117 | if (daemon->randomsocks[i].refcount != 0 && |
| 1118 | FD_ISSET(daemon->randomsocks[i].fd, set)) |
| 1119 | reply_query(daemon->randomsocks[i].fd, daemon->randomsocks[i].family, now); |
| 1120 | |
| 1121 | for (listener = daemon->listeners; listener; listener = listener->next) |
| 1122 | { |
| 1123 | if (listener->fd != -1 && FD_ISSET(listener->fd, set)) |
| 1124 | receive_query(listener, now); |
| 1125 | |
| 1126 | #ifdef HAVE_TFTP |
| 1127 | if (listener->tftpfd != -1 && FD_ISSET(listener->tftpfd, set)) |
| 1128 | tftp_request(listener, now); |
| 1129 | #endif |
| 1130 | |
| 1131 | if (listener->tcpfd != -1 && FD_ISSET(listener->tcpfd, set)) |
| 1132 | { |
| 1133 | int confd; |
| 1134 | struct irec *iface = NULL; |
| 1135 | pid_t p; |
| 1136 | |
| 1137 | while((confd = accept(listener->tcpfd, NULL, NULL)) == -1 && errno == EINTR); |
| 1138 | |
| 1139 | if (confd == -1) |
| 1140 | continue; |
| 1141 | |
| 1142 | if (daemon->options & OPT_NOWILD) |
| 1143 | iface = listener->iface; |
| 1144 | else |
| 1145 | { |
| 1146 | union mysockaddr tcp_addr; |
| 1147 | socklen_t tcp_len = sizeof(union mysockaddr); |
| 1148 | /* Check for allowed interfaces when binding the wildcard address: |
| 1149 | we do this by looking for an interface with the same address as |
| 1150 | the local address of the TCP connection, then looking to see if that's |
| 1151 | an allowed interface. As a side effect, we get the netmask of the |
| 1152 | interface too, for localisation. */ |
| 1153 | |
| 1154 | /* interface may be new since startup */ |
| 1155 | if (enumerate_interfaces() && |
| 1156 | getsockname(confd, (struct sockaddr *)&tcp_addr, &tcp_len) != -1) |
| 1157 | for (iface = daemon->interfaces; iface; iface = iface->next) |
| 1158 | if (sockaddr_isequal(&iface->addr, &tcp_addr)) |
| 1159 | break; |
| 1160 | } |
| 1161 | |
| 1162 | if (!iface) |
| 1163 | { |
| 1164 | shutdown(confd, SHUT_RDWR); |
| 1165 | close(confd); |
| 1166 | } |
| 1167 | #ifndef NO_FORK |
| 1168 | else if (!(daemon->options & OPT_DEBUG) && (p = fork()) != 0) |
| 1169 | { |
| 1170 | if (p != -1) |
| 1171 | { |
| 1172 | int i; |
| 1173 | for (i = 0; i < MAX_PROCS; i++) |
| 1174 | if (daemon->tcp_pids[i] == 0) |
| 1175 | { |
| 1176 | daemon->tcp_pids[i] = p; |
| 1177 | break; |
| 1178 | } |
| 1179 | } |
| 1180 | close(confd); |
| 1181 | } |
| 1182 | #endif |
| 1183 | else |
| 1184 | { |
| 1185 | unsigned char *buff; |
| 1186 | struct server *s; |
| 1187 | int flags; |
| 1188 | struct in_addr dst_addr_4; |
| 1189 | |
| 1190 | dst_addr_4.s_addr = 0; |
| 1191 | |
| 1192 | /* Arrange for SIGALARM after CHILD_LIFETIME seconds to |
| 1193 | terminate the process. */ |
| 1194 | if (!(daemon->options & OPT_DEBUG)) |
| 1195 | alarm(CHILD_LIFETIME); |
| 1196 | |
| 1197 | /* start with no upstream connections. */ |
| 1198 | for (s = daemon->servers; s; s = s->next) |
| 1199 | s->tcpfd = -1; |
| 1200 | |
| 1201 | /* The connected socket inherits non-blocking |
| 1202 | attribute from the listening socket. |
| 1203 | Reset that here. */ |
| 1204 | if ((flags = fcntl(confd, F_GETFL, 0)) != -1) |
| 1205 | fcntl(confd, F_SETFL, flags & ~O_NONBLOCK); |
| 1206 | |
| 1207 | if (listener->family == AF_INET) |
| 1208 | dst_addr_4 = iface->addr.in.sin_addr; |
| 1209 | |
| 1210 | buff = tcp_request(confd, now, dst_addr_4, iface->netmask); |
| 1211 | |
| 1212 | shutdown(confd, SHUT_RDWR); |
| 1213 | close(confd); |
| 1214 | |
| 1215 | if (buff) |
| 1216 | free(buff); |
| 1217 | |
| 1218 | for (s = daemon->servers; s; s = s->next) |
| 1219 | if (s->tcpfd != -1) |
| 1220 | { |
| 1221 | shutdown(s->tcpfd, SHUT_RDWR); |
| 1222 | close(s->tcpfd); |
| 1223 | } |
| 1224 | #ifndef NO_FORK |
| 1225 | if (!(daemon->options & OPT_DEBUG)) |
| 1226 | { |
| 1227 | flush_log(); |
| 1228 | _exit(0); |
| 1229 | } |
| 1230 | #endif |
| 1231 | } |
| 1232 | } |
| 1233 | } |
| 1234 | } |
| 1235 | |
| 1236 | #ifdef HAVE_DHCP |
| 1237 | int make_icmp_sock(void) |
| 1238 | { |
| 1239 | int fd; |
| 1240 | int zeroopt = 0; |
| 1241 | |
| 1242 | if ((fd = socket (AF_INET, SOCK_RAW, IPPROTO_ICMP)) != -1) |
| 1243 | { |
| 1244 | if (!fix_fd(fd) || |
| 1245 | setsockopt(fd, SOL_SOCKET, SO_DONTROUTE, &zeroopt, sizeof(zeroopt)) == -1) |
| 1246 | { |
| 1247 | close(fd); |
| 1248 | fd = -1; |
| 1249 | } |
| 1250 | } |
| 1251 | |
| 1252 | return fd; |
| 1253 | } |
| 1254 | |
| 1255 | int icmp_ping(struct in_addr addr) |
| 1256 | { |
| 1257 | /* Try and get an ICMP echo from a machine. */ |
| 1258 | |
| 1259 | /* Note that whilst in the three second wait, we check for |
| 1260 | (and service) events on the DNS and TFTP sockets, (so doing that |
| 1261 | better not use any resources our caller has in use...) |
| 1262 | but we remain deaf to signals or further DHCP packets. */ |
| 1263 | |
| 1264 | int fd; |
| 1265 | struct sockaddr_in saddr; |
| 1266 | struct { |
| 1267 | struct ip ip; |
| 1268 | struct icmp icmp; |
| 1269 | } packet; |
| 1270 | unsigned short id = rand16(); |
| 1271 | unsigned int i, j; |
| 1272 | int gotreply = 0; |
| 1273 | time_t start, now; |
| 1274 | |
| 1275 | #if defined(HAVE_LINUX_NETWORK) || defined (HAVE_SOLARIS_NETWORK) |
| 1276 | if ((fd = make_icmp_sock()) == -1) |
| 1277 | return 0; |
| 1278 | #else |
| 1279 | int opt = 2000; |
| 1280 | fd = daemon->dhcp_icmp_fd; |
| 1281 | setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt)); |
| 1282 | #endif |
| 1283 | |
| 1284 | saddr.sin_family = AF_INET; |
| 1285 | saddr.sin_port = 0; |
| 1286 | saddr.sin_addr = addr; |
| 1287 | #ifdef HAVE_SOCKADDR_SA_LEN |
| 1288 | saddr.sin_len = sizeof(struct sockaddr_in); |
| 1289 | #endif |
| 1290 | |
| 1291 | memset(&packet.icmp, 0, sizeof(packet.icmp)); |
| 1292 | packet.icmp.icmp_type = ICMP_ECHO; |
| 1293 | packet.icmp.icmp_id = id; |
| 1294 | for (j = 0, i = 0; i < sizeof(struct icmp) / 2; i++) |
| 1295 | j += ((u16 *)&packet.icmp)[i]; |
| 1296 | while (j>>16) |
| 1297 | j = (j & 0xffff) + (j >> 16); |
| 1298 | packet.icmp.icmp_cksum = (j == 0xffff) ? j : ~j; |
| 1299 | |
| 1300 | while (sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0, |
| 1301 | (struct sockaddr *)&saddr, sizeof(saddr)) == -1 && |
| 1302 | retry_send()); |
| 1303 | |
| 1304 | for (now = start = dnsmasq_time(); |
| 1305 | difftime(now, start) < (float)PING_WAIT;) |
| 1306 | { |
| 1307 | struct timeval tv; |
| 1308 | fd_set rset, wset; |
| 1309 | struct sockaddr_in faddr; |
| 1310 | int maxfd = fd; |
| 1311 | socklen_t len = sizeof(faddr); |
| 1312 | |
| 1313 | tv.tv_usec = 250000; |
| 1314 | tv.tv_sec = 0; |
| 1315 | |
| 1316 | FD_ZERO(&rset); |
| 1317 | FD_ZERO(&wset); |
| 1318 | FD_SET(fd, &rset); |
| 1319 | set_dns_listeners(now, &rset, &maxfd); |
| 1320 | set_log_writer(&wset, &maxfd); |
| 1321 | |
| 1322 | if (select(maxfd+1, &rset, &wset, NULL, &tv) < 0) |
| 1323 | { |
| 1324 | FD_ZERO(&rset); |
| 1325 | FD_ZERO(&wset); |
| 1326 | } |
| 1327 | |
| 1328 | now = dnsmasq_time(); |
| 1329 | |
| 1330 | check_log_writer(&wset); |
| 1331 | check_dns_listeners(&rset, now); |
| 1332 | |
| 1333 | #ifdef HAVE_TFTP |
| 1334 | check_tftp_listeners(&rset, now); |
| 1335 | #endif |
| 1336 | |
| 1337 | if (FD_ISSET(fd, &rset) && |
| 1338 | recvfrom(fd, &packet, sizeof(packet), 0, |
| 1339 | (struct sockaddr *)&faddr, &len) == sizeof(packet) && |
| 1340 | saddr.sin_addr.s_addr == faddr.sin_addr.s_addr && |
| 1341 | packet.icmp.icmp_type == ICMP_ECHOREPLY && |
| 1342 | packet.icmp.icmp_seq == 0 && |
| 1343 | packet.icmp.icmp_id == id) |
| 1344 | { |
| 1345 | gotreply = 1; |
| 1346 | break; |
| 1347 | } |
| 1348 | } |
| 1349 | |
| 1350 | #if defined(HAVE_LINUX_NETWORK) || defined(HAVE_SOLARIS_NETWORK) |
| 1351 | close(fd); |
| 1352 | #else |
| 1353 | opt = 1; |
| 1354 | setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt)); |
| 1355 | #endif |
| 1356 | |
| 1357 | return gotreply; |
| 1358 | } |
| 1359 | #endif |