src/script.c

   1 /**
   2  * Copyright (C) 2012-2014 Steven Barth <steven@midlink.org>
   3  * Copyright (C) 2017-2018 Hans Dedecker <dedeckeh@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License v2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <stdio.h>
  17 #include <netdb.h>
  18 #include <resolv.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <syslog.h>
  22 #include <signal.h>
  23 #include <unistd.h>
  24 #include <inttypes.h>
  25 #include <arpa/inet.h>
  26 #include <sys/wait.h>
  27 #include <netinet/in.h>
  28
  29 #include "odhcp6c.h"
  30
  31 static const char hexdigits[] = "0123456789abcdef";
  32 static const int8_t hexvals[] = {
  33     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
  34     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  35     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  36      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
  37     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  38     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  39     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  40     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  41 };
  42
  43 static char action[16] = "";
  44 static char *argv[4] = {NULL, NULL, action, NULL};
  45 static volatile pid_t running = 0;
  46 static time_t started;
  47
  48 static void script_sighandle(int signal)
  49 {
  50         if (signal == SIGCHLD) {
  51                 pid_t child;
  52
  53                 while ((child = waitpid(-1, NULL, WNOHANG)) > 0)
  54                         if (running == child)
  55                                 running = 0;
  56         }
  57 }
  58
  59 int script_init(const char *path, const char *ifname)
  60 {
  61         argv[0] = (char*)path;
  62         argv[1] = (char*)ifname;
  63         signal(SIGCHLD, script_sighandle);
  64
  65         return 0;
  66 }
  67
  68 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  69 {
  70         size_t c;
  71
  72         for (c = 0; c < len && src[0] && src[1]; ++c) {
  73                 int8_t x = (int8_t)*src++;
  74                 int8_t y = (int8_t)*src++;
  75                 if (x < 0 || (x = hexvals[x]) < 0
  76                                 || y < 0 || (y = hexvals[y]) < 0)
  77                         return -1;
  78                 dst[c] = x << 4 | y;
  79                 while (((int8_t)*src) < 0 ||
  80                                 (*src && hexvals[(uint8_t)*src] < 0))
  81                         src++;
  82         }
  83
  84         return c;
  85 }
  86
  87 static void script_hexlify(char *dst, const uint8_t *src, size_t len)
  88 {
  89         for (size_t i = 0; i < len; ++i) {
  90                 *dst++ = hexdigits[src[i] >> 4];
  91                 *dst++ = hexdigits[src[i] & 0x0f];
  92         }
  93
  94         *dst = 0;
  95 }
  96
  97 static void ipv6_to_env(const char *name,
  98                 const struct in6_addr *addr, size_t cnt)
  99 {
 100         size_t buf_len = strlen(name);
 101         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
 102
 103         memcpy(buf, name, buf_len);
 104         buf[buf_len++] = '=';
 105
 106         for (size_t i = 0; i < cnt; ++i) {
 107                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
 108                 buf_len += strlen(&buf[buf_len]);
 109                 buf[buf_len++] = ' ';
 110         }
 111
 112         if (buf[buf_len - 1] == ' ')
 113                 buf_len--;
 114
 115         buf[buf_len] = '\0';
 116         putenv(buf);
 117 }
 118
 119 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
 120 {
 121         size_t buf_len = strlen(name);
 122         size_t buf_size = len + buf_len + 2;
 123         const uint8_t *fqdn_end = fqdn + len;
 124         char *buf = realloc(NULL, len + buf_len + 2);
 125
 126         memcpy(buf, name, buf_len);
 127         buf[buf_len++] = '=';
 128
 129         while (fqdn < fqdn_end) {
 130                 int l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
 131                 if (l <= 0)
 132                         break;
 133                 fqdn += l;
 134                 buf_len += strlen(&buf[buf_len]);
 135                 buf[buf_len++] = ' ';
 136         }
 137
 138         if (buf[buf_len - 1] == ' ')
 139                 buf_len--;
 140
 141         buf[buf_len] = '\0';
 142         putenv(buf);
 143 }
 144
 145 static void bin_to_env(uint8_t *opts, size_t len)
 146 {
 147         uint8_t *oend = opts + len, *odata;
 148         uint16_t otype, olen;
 149
 150         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 151                 char *buf = realloc(NULL, 14 + (olen * 2));
 152                 size_t buf_len = 0;
 153
 154                 snprintf(buf, 14, "OPTION_%hu=", otype);
 155                 buf_len += strlen(buf);
 156
 157                 script_hexlify(&buf[buf_len], odata, olen);
 158                 putenv(buf);
 159         }
 160 }
 161
 162 enum entry_type {
 163         ENTRY_ADDRESS,
 164         ENTRY_HOST,
 165         ENTRY_ROUTE,
 166         ENTRY_PREFIX
 167 };
 168
 169 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 170 {
 171         size_t buf_len = strlen(name);
 172         const struct odhcp6c_entry *e = data;
 173         // Worst case: ENTRY_PREFIX with iaid != 1 and exclusion
 174         const size_t max_entry_len = (INET6_ADDRSTRLEN-1 + 5 + 22 + 15 + 10 +
 175                                       INET6_ADDRSTRLEN-1 + 11 + 1);
 176         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * max_entry_len);
 177
 178         memcpy(buf, name, buf_len);
 179         buf[buf_len++] = '=';
 180
 181         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 182                 /*
 183                  * The only invalid entries allowed to be passed to the script are prefix entries.
 184                  * This will allow immediate removal of the old ipv6-prefix-assignment that might
 185                  * otherwise be kept for up to 2 hours (see L-13 requirement of RFC 7084).
 186                  */
 187                 if (!e[i].valid && type != ENTRY_PREFIX)
 188                         continue;
 189
 190                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 191                 buf_len += strlen(&buf[buf_len]);
 192
 193                 if (type != ENTRY_HOST) {
 194                         snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
 195                         buf_len += strlen(&buf[buf_len]);
 196
 197                         if (type == ENTRY_ROUTE) {
 198                                 buf[buf_len++] = ',';
 199
 200                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 201                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 202                                         buf_len += strlen(&buf[buf_len]);
 203                                 }
 204
 205                                 snprintf(&buf[buf_len], 23, ",%u,%u", e[i].valid, e[i].priority);
 206                                 buf_len += strlen(&buf[buf_len]);
 207                         } else {
 208                                 snprintf(&buf[buf_len], 23, ",%u,%u", e[i].preferred, e[i].valid);
 209                                 buf_len += strlen(&buf[buf_len]);
 210                         }
 211
 212                         if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1) {
 213                                 snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
 214                                 buf_len += strlen(&buf[buf_len]);
 215                         }
 216
 217                         if (type == ENTRY_PREFIX && e[i].priority) {
 218                                 // priority and router are abused for prefix exclusion
 219                                 snprintf(&buf[buf_len], 11, ",excluded=");
 220                                 buf_len += strlen(&buf[buf_len]);
 221                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 222                                 buf_len += strlen(&buf[buf_len]);
 223                                 snprintf(&buf[buf_len], 12, "/%u", e[i].priority);
 224                                 buf_len += strlen(&buf[buf_len]);
 225                         }
 226                 }
 227
 228                 buf[buf_len++] = ' ';
 229         }
 230
 231         if (buf[buf_len - 1] == ' ')
 232                 buf_len--;
 233
 234         buf[buf_len] = '\0';
 235         putenv(buf);
 236 }
 237
 238 static void search_to_env(const char *name, const uint8_t *start, size_t len)
 239 {
 240         size_t buf_len = strlen(name);
 241         char *buf = realloc(NULL, buf_len + 2 + len);
 242         char *c = mempcpy(buf, name, buf_len);
 243         *c++ = '=';
 244
 245         for (struct odhcp6c_entry *e = (struct odhcp6c_entry*)start;
 246                                 (uint8_t*)e < &start[len] &&
 247                                 (uint8_t*)odhcp6c_next_entry(e) <= &start[len];
 248                                 e = odhcp6c_next_entry(e)) {
 249                 if (!e->valid)
 250                         continue;
 251                 c = mempcpy(c, e->auxtarget, e->auxlen);
 252                 *c++ = ' ';
 253         }
 254
 255         if (c[-1] == ' ')
 256                 c--;
 257
 258         *c = '\0';
 259         putenv(buf);
 260 }
 261
 262 static void int_to_env(const char *name, int value)
 263 {
 264         size_t len = 13 + strlen(name);
 265         char *buf = realloc(NULL, len);
 266
 267         snprintf(buf, len, "%s=%d", name, value);
 268         putenv(buf);
 269 }
 270
 271 static void s46_to_env_portparams(const uint8_t *data, size_t len, FILE *fp)
 272 {
 273         uint8_t *odata;
 274         uint16_t otype, olen;
 275
 276         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 277                 if (otype == DHCPV6_OPT_S46_PORTPARAMS &&
 278                                 olen == sizeof(struct dhcpv6_s46_portparams)) {
 279                         struct dhcpv6_s46_portparams *params = (void*)odata;
 280                         fprintf(fp, "offset=%d,psidlen=%d,psid=%d,",
 281                                         params->offset, params->psid_len, ntohs(params->psid));
 282                 }
 283         }
 284 }
 285
 286 static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len)
 287 {
 288         const char *name = (state == STATE_S46_MAPE) ? "MAPE" :
 289                         (state == STATE_S46_MAPT) ? "MAPT" : "LW4O6";
 290
 291         if (len == 0)
 292                 return;
 293
 294         char *str;
 295         size_t strsize;
 296
 297         FILE *fp = open_memstream(&str, &strsize);
 298         fputs(name, fp);
 299         fputc('=', fp);
 300
 301         const char *type = (state == STATE_S46_MAPE) ? "map-e" :
 302                         (state == STATE_S46_MAPT) ? "map-t" : "lw4o6";
 303
 304         uint8_t *odata;
 305         uint16_t otype, olen;
 306
 307         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 308                 struct dhcpv6_s46_rule *rule = (struct dhcpv6_s46_rule*)odata;
 309                 struct dhcpv6_s46_v4v6bind *bind = (struct dhcpv6_s46_v4v6bind*)odata;
 310
 311                 if (state != STATE_S46_LW && otype == DHCPV6_OPT_S46_RULE &&
 312                                 olen >= sizeof(struct dhcpv6_s46_rule)) {
 313                         char buf4[INET_ADDRSTRLEN];
 314                         char buf6[INET6_ADDRSTRLEN];
 315                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 316
 317                         size_t prefix6len = rule->prefix6_len;
 318                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 319
 320                         if (prefix6len > sizeof(in6) ||
 321                             olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
 322                                 continue;
 323
 324                         memcpy(&in6, rule->ipv6_prefix, prefix6len);
 325
 326                         inet_ntop(AF_INET, &rule->ipv4_prefix, buf4, sizeof(buf4));
 327                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 328
 329                         if (rule->flags & 1)
 330                                 fputs("fmr,", fp);
 331
 332                         fprintf(fp, "type=%s,ealen=%d,prefix4len=%d,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
 333                                         type, rule->ea_len, rule->prefix4_len, rule->prefix6_len, buf4, buf6);
 334
 335                         s46_to_env_portparams(&rule->ipv6_prefix[prefix6len],
 336                                         olen - sizeof(*rule) - prefix6len, fp);
 337
 338                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 339                                 if (state != STATE_S46_MAPT && otype == DHCPV6_OPT_S46_BR &&
 340                                                 olen == sizeof(struct in6_addr)) {
 341                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 342                                         fprintf(fp, "br=%s,", buf6);
 343                                 } else if (state == STATE_S46_MAPT && otype == DHCPV6_OPT_S46_DMR &&
 344                                                 olen >= sizeof(struct dhcpv6_s46_dmr)) {
 345                                         struct dhcpv6_s46_dmr *dmr = (struct dhcpv6_s46_dmr*)odata;
 346                                         memset(&in6, 0, sizeof(in6));
 347                                         size_t prefix6len = dmr->dmr_prefix6_len;
 348                                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 349
 350                                         if (prefix6len > sizeof(in6) ||
 351                                             olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
 352                                                 continue;
 353
 354                                         memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len);
 355                                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 356                                         fprintf(fp, "dmr=%s/%d,", buf6, dmr->dmr_prefix6_len);
 357                                 }
 358                         }
 359
 360                         fputc(' ', fp);
 361                 } else if (state == STATE_S46_LW && otype == DHCPV6_OPT_S46_V4V6BIND &&
 362                                 olen >= sizeof(struct dhcpv6_s46_v4v6bind)) {
 363                         char buf4[INET_ADDRSTRLEN];
 364                         char buf6[INET6_ADDRSTRLEN];
 365                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 366
 367                         size_t prefix6len = bind->bindprefix6_len;
 368                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 369
 370                         if (prefix6len > sizeof(in6) ||
 371                             olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
 372                                 continue;
 373
 374                         memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);
 375
 376                         inet_ntop(AF_INET, &bind->ipv4_address, buf4, sizeof(buf4));
 377                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 378
 379                         fprintf(fp, "type=%s,prefix4len=32,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
 380                                         type, bind->bindprefix6_len, buf4, buf6);
 381
 382                         s46_to_env_portparams(&bind->bind_ipv6_prefix[prefix6len],
 383                                         olen - sizeof(*bind) - prefix6len, fp);
 384
 385                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 386                                 if (otype == DHCPV6_OPT_S46_BR && olen == sizeof(struct in6_addr)) {
 387                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 388                                         fprintf(fp, "br=%s,", buf6);
 389                                 }
 390                         }
 391
 392                         fputc(' ', fp);
 393                 }
 394         }
 395
 396         fclose(fp);
 397         putenv(str);
 398 }
 399
 400 void script_call(const char *status, int delay, bool resume)
 401 {
 402         time_t now = odhcp6c_get_milli_time() / 1000;
 403         bool running_script = false;
 404
 405         if (running) {
 406                 time_t diff = now - started;
 407
 408                 kill(running, SIGTERM);
 409
 410                 if (diff > delay)
 411                         delay -= diff;
 412                 else
 413                         delay = 0;
 414
 415                 running_script = true;
 416         }
 417
 418         if (resume || !running_script || !action[0])
 419                 strncpy(action, status, sizeof(action) - 1);
 420
 421         pid_t pid = fork();
 422
 423         if (pid > 0) {
 424                 running = pid;
 425                 started = now;
 426
 427                 if (!resume)
 428                         action[0] = 0;
 429
 430         } else if (pid == 0) {
 431                 size_t dns_len, search_len, custom_len, sntp_ip_len, ntp_ip_len, ntp_dns_len;
 432                 size_t sip_ip_len, sip_fqdn_len, aftr_name_len, cer_len, addr_len;
 433                 size_t s46_mapt_len, s46_mape_len, s46_lw_len, passthru_len;
 434
 435                 signal(SIGTERM, SIG_DFL);
 436                 if (delay > 0) {
 437                         sleep(delay);
 438                         odhcp6c_expire(false);
 439                 }
 440
 441                 struct in6_addr *addr = odhcp6c_get_state(STATE_SERVER_ADDR, &addr_len);
 442                 struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 443                 uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 444                 uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 445                 struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 446                 struct in6_addr *ntp = odhcp6c_get_state(STATE_NTP_IP, &ntp_ip_len);
 447                 uint8_t *ntp_dns = odhcp6c_get_state(STATE_NTP_FQDN, &ntp_dns_len);
 448                 struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 449                 uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 450                 uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 451                 struct in6_addr *cer = odhcp6c_get_state(STATE_CER, &cer_len);
 452                 uint8_t *s46_mapt = odhcp6c_get_state(STATE_S46_MAPT, &s46_mapt_len);
 453                 uint8_t *s46_mape = odhcp6c_get_state(STATE_S46_MAPE, &s46_mape_len);
 454                 uint8_t *s46_lw = odhcp6c_get_state(STATE_S46_LW, &s46_lw_len);
 455                 uint8_t *passthru = odhcp6c_get_state(STATE_PASSTHRU, &passthru_len);
 456
 457                 size_t prefix_len, address_len, ra_pref_len,
 458                         ra_route_len, ra_dns_len, ra_search_len;
 459                 uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 460                 uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 461                 uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 462                 uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 463                 uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 464                 uint8_t *ra_search = odhcp6c_get_state(STATE_RA_SEARCH, &ra_search_len);
 465
 466                 ipv6_to_env("SERVER", addr, addr_len / sizeof(*addr));
 467                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 468                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 469                 ipv6_to_env("NTP_IP", ntp, ntp_ip_len / sizeof(*ntp));
 470                 fqdn_to_env("NTP_FQDN", ntp_dns, ntp_dns_len);
 471                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 472                 fqdn_to_env("DOMAINS", search, search_len);
 473                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 474                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 475                 ipv6_to_env("CER", cer, cer_len / sizeof(*cer));
 476                 s46_to_env(STATE_S46_MAPE, s46_mape, s46_mape_len);
 477                 s46_to_env(STATE_S46_MAPT, s46_mapt, s46_mapt_len);
 478                 s46_to_env(STATE_S46_LW, s46_lw, s46_lw_len);
 479                 bin_to_env(custom, custom_len);
 480
 481                 if (odhcp6c_is_bound()) {
 482                         entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 483                         entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 484                 }
 485
 486                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 487                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 488                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 489                 search_to_env("RA_DOMAINS", ra_search, ra_search_len);
 490
 491                 int_to_env("RA_HOPLIMIT", ra_get_hoplimit());
 492                 int_to_env("RA_MTU", ra_get_mtu());
 493                 int_to_env("RA_REACHABLE", ra_get_reachable());
 494                 int_to_env("RA_RETRANSMIT", ra_get_retransmit());
 495
 496                 char *buf = malloc(10 + passthru_len * 2);
 497                 strncpy(buf, "PASSTHRU=", 10);
 498                 script_hexlify(&buf[9], passthru, passthru_len);
 499                 putenv(buf);
 500
 501                 execv(argv[0], argv);
 502                 _exit(128);
 503         }
 504 }