src/script.c

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