release/src/router/ntpc/ntpc.c

   1 /*
   2
   3         ntpc/ntpsync
   4         Copyright (C) 2006-2009 Jonathan Zarate
   5
   6         Licensed under GNU GPL v2 or later.
   7
   8 */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/socket.h>
  14 #include <netdb.h>
  15 #include <arpa/inet.h>
  16 #include <time.h>
  17 #include <unistd.h>
  18 #include <sys/time.h>
  19 #include <signal.h>
  20 #include <syslog.h>
  21
  22 #include <bcmnvram.h>
  23 #include <shutils.h>
  24 #include <shared.h>
  25
  26
  27 #define _dprintf(args...) do { } while (0);
  28 //      #define _dprintf(args...) cprintf(args)
  29
  30
  31 #define I_MISC          0
  32 #define I_ORTIME        6
  33 #define I_TXTIME        10
  34
  35 #define TIMEFIX         2208988800UL
  36
  37
  38 static void add_word(char *buffer, const char *word, int max)
  39 {
  40         if ((*buffer != 0) && (buffer[strlen(buffer) - 1] != ' '))
  41                 strlcat(buffer, " ", max);
  42         strlcat(buffer, word, max);
  43 }
  44
  45 // 0 = ok, 1 = failed, 2 = permanent failure
  46 static int ntpc(struct in_addr addr)
  47 {
  48         uint32_t packet[12];
  49         struct timeval txtime;
  50         struct timeval rxtime;
  51         struct timeval tv;
  52         uint32_t u;
  53         uint32_t txn;
  54         int fd;
  55         fd_set fds;
  56         int len;
  57         struct sockaddr_in sa;
  58         char s[64], q[128];
  59         time_t t;
  60         time_t ntpt;
  61         time_t diff;
  62
  63         memset(&sa, 0, sizeof(sa));
  64         sa.sin_addr = addr;
  65         sa.sin_port = htons(123);
  66         sa.sin_family = AF_INET;
  67
  68         if ((fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) {
  69                 printf("Unable to create a socket\n");
  70                 return 1;
  71         }
  72
  73         if (connect(fd, (struct sockaddr*)&sa, sizeof(sa)) == -1) {
  74                 printf("Unable to connect\n");
  75         }
  76         else {
  77                 memset(&packet, 0, sizeof(packet));
  78                 packet[I_MISC] = htonl((4 << 27) | (3 << 24));  // VN=v4 | mode=3 (client)
  79 //              packet[I_MISC] = htonl((3 << 27) | (3 << 24));  // VN=v3 | mode=3 (client)
  80                 gettimeofday(&txtime, NULL);
  81                 packet[I_TXTIME] = txn = htonl(txtime.tv_sec + TIMEFIX);
  82                 send(fd, packet, sizeof(packet), 0);
  83
  84                 FD_ZERO(&fds);
  85                 FD_SET(fd, &fds);
  86                 tv.tv_sec = 3;  // no more than 3 seconds
  87                 tv.tv_usec = 0;
  88                 if (select(fd + 1, &fds, NULL, NULL, &tv) != 1) {
  89                         printf("Timeout\n");
  90                 }
  91                 else {
  92                         len = recv(fd, packet, sizeof(packet), 0);
  93                         if (len != sizeof(packet)) {
  94                                 printf("Invalid packet size\n");
  95                         }
  96                         else {
  97                                 gettimeofday(&rxtime, NULL);
  98
  99                                 u = ntohl(packet[0]);
 100
 101                                 _dprintf("u = 0x%08x\n", u);
 102                                 _dprintf("LI = %u\n", u >> 30);
 103                                 _dprintf("VN = %u\n", (u >> 27) & 0x07);
 104                                 _dprintf("mode = %u\n", (u >> 24) & 0x07);
 105                                 _dprintf("stratum = %u\n", (u >> 16) & 0xFF);
 106                                 _dprintf("poll interval = %u\n", (u >> 8) & 0xFF);
 107                                 _dprintf("precision = %u\n", u & 0xFF);
 108
 109                                 if ((u & 0x07000000) != 0x04000000) {   // mode != 4 (server)
 110                                         printf("Invalid response\n");
 111                                 }
 112                                 else {
 113                                         close(fd);
 114
 115                                         // notes:
 116                                         //      - Windows' ntpd returns vn=3, stratum=0
 117
 118                                         if ((u & 0x00FF0000) == 0) {                    // stratum == 0
 119                                                 printf("Received stratum=0\n");
 120                                                 if (!nvram_match("ntp_kiss_ignore", "1")) {
 121                                                         return 2;
 122                                                 }
 123                                         }
 124
 125                                         ntpt = ntohl(packet[I_TXTIME]) - TIMEFIX;
 126                                         t = (rxtime.tv_sec - txtime.tv_sec) >> 1;
 127                                         diff = (ntpt - rxtime.tv_sec) + t;
 128
 129                                         _dprintf("txtime = %ld\n", txtime.tv_sec);
 130                                         _dprintf("rxtime = %ld\n", rxtime.tv_sec);
 131                                         _dprintf("ntpt   = %ld\n", ntpt);
 132                                         _dprintf("rtt/2  = %ld\n", t);
 133                                         _dprintf("diff   = %ld\n", diff);
 134
 135                                         if (diff != 0) {
 136                                                 gettimeofday(&tv, NULL);
 137                                                 tv.tv_sec  += diff;
 138 //                                              tv.tv_usec = 0;// sorry, I'm not a time geek :P
 139                                                 settimeofday(&tv, NULL);
 140
 141                                                 _dprintf("new    = %lu\n", tv.tv_sec);
 142
 143                                                 strftime(s, sizeof(s), "%a, %d %b %Y %H:%M:%S %z", localtime(&tv.tv_sec));
 144                                                 sprintf(q, "Time Updated: %s [%s%lds]", s, diff > 0 ? "+" : "", diff);
 145                                                 printf("\n\n%s\n", q);
 146                                                 syslog(LOG_INFO, q);
 147                                         }
 148                                         else {
 149                                                 t = time(0);
 150                                                 strftime(s, sizeof(s), "%a, %d %b %Y %H:%M:%S %z", localtime(&t));
 151                                                 printf("\n\n%s\nNo change was needed.\n", s);
 152                                         }
 153                                         return 0;
 154                                 }
 155                         }
 156                 }
 157         }
 158
 159         close(fd);
 160         return 1;
 161 }
 162
 163
 164 // -----------------------------------------------------------------------------
 165
 166
 167 static int ntpc_main(int argc, char **argv)
 168 {
 169         struct hostent *he;
 170         struct in_addr ia;
 171         const char *s;
 172         int i;
 173
 174         for (i = 1; i < argc; ++i) {
 175                 if ((he = gethostbyname(argv[i])) != NULL) {
 176                         memcpy(&ia, he->h_addr_list[0], sizeof(ia));
 177                         s = inet_ntoa(ia);
 178                         if (strcmp(s, argv[i]) == 0) printf("Trying %s: ", s);
 179                                 else printf("Trying %s [%s]:", argv[i], s);
 180                         if (ntpc(ia) == 0) return 0;
 181                 }
 182                 else {
 183                         printf("Unable to resolve: %s\n", argv[i]);
 184                 }
 185         }
 186
 187         if (argc < 2) {
 188                 printf("Usage: ntpc <server>\n");
 189         }
 190
 191         return 1;
 192 }
 193
 194
 195 // -----------------------------------------------------------------------------
 196
 197
 198 static int ntpsync_main(int argc, char **argv)
 199 {
 200         char *servers, *t, *p;
 201         char *addr[10];
 202         char *ips;
 203         char *nvkiss;
 204         int count;
 205         int i;
 206         struct hostent *he;
 207         struct in_addr ia;
 208         int retries;
 209         int nu;
 210         char s[512];
 211         time_t tt;
 212         struct tm *tms;
 213         enum { USER, INIT, CRON } mode;
 214
 215         nu = nvram_get_int("ntp_updates");
 216
 217         mode = USER;
 218         if (argc == 2) {
 219                 if (strcmp(argv[1], "--cron") == 0) {           // try for a few minutes
 220                         if (nu <= 0) {
 221                                 system("cru d ntpsync");
 222                                 return 0;
 223                         }
 224                         mode = CRON;
 225                 }
 226                 else if (strcmp(argv[1], "--init") == 0) {      // try forever, schedule cron job
 227                         if (fork() != 0) return 0;
 228                         mode = INIT;
 229                 }
 230                 else {
 231                         return 1;
 232                 }
 233         }
 234         else if (argc != 1) {
 235                 return 1;
 236         }
 237
 238         _dprintf("[ntpsync %ld] start\n", get_uptime());
 239
 240         if ((get_wan_proto() != WP_DISABLED) && (mode != INIT) &&
 241                 (!check_wanup()) && (nvram_match("ntp_tdod", "0"))) {
 242                 _dprintf("WAN is down, not updating.");
 243                 return 1;
 244         }
 245
 246         srand(time(0));
 247         retries = 0;
 248
 249         while (1) {
 250                 _dprintf("[ntpsync %ld] while\n", get_uptime());
 251
 252                 count = 0;
 253                 servers = p = strdup(nvram_safe_get("ntp_server"));
 254                 if (!servers) {
 255                         printf("Not enough memory\n");
 256                         return 1;
 257                 }
 258                 while ((count < 10) && ((t = strsep(&p, " ")) != NULL)) {
 259                         if (*t != 0) addr[count++] = t;
 260                 }
 261                 if (count == 0) addr[count++] = "pool.ntp.org";
 262
 263                 while (count > 0) {
 264                         i = (rand() % count);
 265                         _dprintf("[ntpsync] i=%d addr=%s\n", i, addr[i]);
 266
 267                         if ((he = gethostbyname(addr[i])) != NULL) {
 268                                 memcpy(&ia, he->h_addr_list[0], sizeof(ia));
 269                                 ips = inet_ntoa(ia);
 270                                 _dprintf("ip = %s\n", ips);
 271
 272                                 nvkiss = nvram_safe_get("ntp_kiss");
 273                                 if (find_word(nvkiss, ips)) {
 274                                         _dprintf("kiss: %s\n", ips);
 275                                 }
 276                                 else {
 277                                         switch (ntpc(ia)) {
 278                                         case 0:
 279                                                 _dprintf("[ntpsync] %ld OK\n", get_uptime());
 280                                                 if (mode == INIT) {
 281                                                         tt = time(0);
 282                                                         if ((nu > 0) && ((tms = localtime(&tt)) != NULL)) {
 283
 284                                                                 // add some randomness to make the servers happier / avoid the xx:00 rush
 285                                                                 sprintf(s, "cru a ntpsync \"%d ", (tms->tm_min + 20 + (rand() % 20)) % 60);
 286
 287                                                                 // schedule every nu hours
 288                                                                 for (i = 0; i < 24; ++i) {
 289                                                                         if ((i % nu) == 0) sprintf(s + strlen(s), "%s%d", i ? "," : "", (i + tms->tm_hour + 1)  % 24);
 290                                                                 }
 291                                                                 strcat(s, " * * * ntpsync --cron\"");
 292                                                                 system(s);
 293                                                         }
 294                                                 }
 295
 296                                                 // make sure access restriction is ok
 297                                                 system("rcheck");
 298                                                 _dprintf("[ntpsync] %ld exit\n", get_uptime());
 299                                                 return 0;
 300                                         case 2:
 301                                                 while ((nvkiss) && (strlen(nvkiss) > 128)) nvkiss = strchr(nvkiss + 1, ' ');
 302                                                 if (nvkiss) strlcpy(s, nvkiss, sizeof(s));
 303                                                         else s[0] = 0;
 304                                                 add_word(s, ips, sizeof(s));
 305                                                 nvram_set("ntp_kiss", s);
 306                                                 syslog(LOG_WARNING, "Received a kiss of death packet from %s (%s).", addr[i], ips);
 307                                                 break;
 308                                         }
 309                                 }
 310                         }
 311
 312                         addr[i] = addr[--count];
 313                 }
 314                 free(servers);
 315
 316                 if (mode == USER) break;
 317                 if ((mode == CRON) && (retries == 5)) break;
 318
 319                 if (++retries > 300) retries = 300;             // 5m
 320                 _dprintf("[ntpsync %ld] sleep=%d\n", get_uptime(), retries);
 321                 sleep(retries);
 322         }
 323
 324         _dprintf("[ntpsync] %ld exit\n", get_uptime());
 325         return 1;
 326 }
 327
 328 // -----------------------------------------------------------------------------
 329
 330
 331 static int ntpstep_main(int argc, char **argv)
 332 {
 333         struct timeval tv;
 334         char s[256];
 335
 336         if (argc != 2) {
 337                 printf("Usage: ntpstep <seconds>\n");
 338                 return 1;
 339         }
 340
 341         gettimeofday(&tv, NULL);
 342         tv.tv_sec += atol(argv[1]);
 343         settimeofday(&tv, NULL);
 344
 345         strftime(s, sizeof(s), "%a, %d %b %Y %H:%M:%S %z", localtime(&tv.tv_sec));
 346         printf("%s\n", s);
 347         return 0;
 348 }
 349
 350
 351 // -----------------------------------------------------------------------------
 352
 353 int main(int argc, char **argv)
 354 {
 355         openlog("ntpc", LOG_PID, LOG_USER);
 356         if (!nvram_contains_word("log_events", "ntp")) {
 357                 setlogmask(LOG_MASK(LOG_EMERG));        // can't set to 0
 358         }
 359
 360         if (strstr(argv[0], "ntpsync") != NULL) return ntpsync_main(argc, argv);
 361         if (strstr(argv[0], "ntpstep") != NULL) return ntpstep_main(argc, argv);
 362
 363         return ntpc_main(argc, argv);
 364 }
 365
 366
 367 /*
 368
 369                        1                   2                    3
 370    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9  0 1
 371   +---+-----+-----+---------------+---------------+----------------+
 372   |LI | VN  |Mode |    Stratum    |     Poll      |   Precision    | 0
 373   +---+-----+-----+---------------+---------------+----------------+
 374   |                          Root  Delay                           | 1
 375   +----------------------------------------------------------------+
 376   |                       Root  Dispersion                         | 2
 377   +----------------------------------------------------------------+
 378   |                     Reference Identifier                       | 3
 379   +----------------------------------------------------------------+
 380   |                    Reference Timestamp (64)                    | 4
 381   +----------------------------------------------------------------+
 382   |                    Originate Timestamp (64)                    | 6
 383   +----------------------------------------------------------------+
 384   |                     Receive Timestamp (64)                     | 8
 385   +----------------------------------------------------------------+
 386   |                     Transmit Timestamp (64)                    | 10
 387   +----------------------------------------------------------------+
 388   |                 Key Identifier (optional) (32)                 | 12
 389   +----------------------------------------------------------------+
 390   |                 Message Digest (optional) (128)                | 13+
 391   +----------------------------------------------------------------+
 392
 393 timestamp:
 394         since 1900
 395
 396 1970-1900:
 397         25,567 days can be converted to one of these units:
 398                 * 2,208,988,800 seconds
 399                 * 36,816,480 minutes
 400                 * 613,608 hours
 401                 * 3652 weeks (rounded down)
 402
 403 refs:
 404         http://www.faqs.org/rfcs/rfc2030.html
 405         http://www.ntp.org/ntpfaq/NTP-s-algo.htm
 406
 407 */