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 <netinet/in.h>
  26
  27 #include "odhcp6c.h"
  28
  29 static const char hexdigits[] = "0123456789abcdef";
  30 static const int8_t hexvals[] = {
  31     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
  32     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  33     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  34      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
  35     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  36     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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 };
  40
  41
  42
  43 static char *argv[4] = {NULL, NULL, NULL, NULL};
  44
  45
  46 int script_init(const char *path, const char *ifname)
  47 {
  48         argv[0] = (char*)path;
  49         argv[1] = (char*)ifname;
  50         return 0;
  51 }
  52
  53
  54 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  55 {
  56         size_t c;
  57         for (c = 0; c < len && src[0] && src[1]; ++c) {
  58                 int8_t x = (int8_t)*src++;
  59                 int8_t y = (int8_t)*src++;
  60                 if (x < 0 || (x = hexvals[x]) < 0
  61                                 || y < 0 || (y = hexvals[y]) < 0)
  62                         return -1;
  63                 dst[c] = x << 4 | y;
  64                 while (((int8_t)*src) < 0 ||
  65                                 (*src && hexvals[(uint8_t)*src] < 0))
  66                         src++;
  67         }
  68
  69         return c;
  70 }
  71
  72
  73 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
  74         for (size_t i = 0; i < len; ++i) {
  75                 *dst++ = hexdigits[src[i] >> 4];
  76                 *dst++ = hexdigits[src[i] & 0x0f];
  77         }
  78         *dst = 0;
  79 }
  80
  81
  82 static void ipv6_to_env(const char *name,
  83                 const struct in6_addr *addr, size_t cnt)
  84 {
  85         size_t buf_len = strlen(name);
  86         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
  87         memcpy(buf, name, buf_len);
  88         buf[buf_len++] = '=';
  89         for (size_t i = 0; i < cnt; ++i) {
  90                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
  91                 buf_len += strlen(&buf[buf_len]);
  92                 buf[buf_len++] = ' ';
  93         }
  94         buf[buf_len - 1] = '\0';
  95         putenv(buf);
  96 }
  97
  98
  99 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
 100 {
 101         size_t buf_len = strlen(name);
 102         size_t buf_size = len + buf_len + 2;
 103         const uint8_t *fqdn_end = fqdn + len;
 104         char *buf = realloc(NULL, len + buf_len + 2);
 105         memcpy(buf, name, buf_len);
 106         buf[buf_len++] = '=';
 107         int l = 1;
 108         while (l > 0 && fqdn < fqdn_end) {
 109                 l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
 110                 fqdn += l;
 111                 buf_len += strlen(&buf[buf_len]);
 112                 buf[buf_len++] = ' ';
 113         }
 114         buf[buf_len - 1] = '\0';
 115         putenv(buf);
 116 }
 117
 118 static void bin_to_env(uint8_t *opts, size_t len)
 119 {
 120         uint8_t *oend = opts + len, *odata;
 121         uint16_t otype, olen;
 122         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 123                 char *buf = realloc(NULL, 14 + (olen * 2));
 124                 size_t buf_len = 0;
 125
 126                 snprintf(buf, 14, "OPTION_%hu=", otype);
 127                 buf_len += strlen(buf);
 128
 129                 script_hexlify(&buf[buf_len], odata, olen);
 130                 putenv(buf);
 131         }
 132 }
 133
 134 enum entry_type {
 135         ENTRY_ADDRESS,
 136         ENTRY_HOST,
 137         ENTRY_ROUTE,
 138         ENTRY_PREFIX
 139 };
 140
 141 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 142 {
 143         size_t buf_len = strlen(name);
 144         const struct odhcp6c_entry *e = data;
 145         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
 146         memcpy(buf, name, buf_len);
 147         buf[buf_len++] = '=';
 148
 149         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 150                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 151                 buf_len += strlen(&buf[buf_len]);
 152                 if (type != ENTRY_HOST) {
 153                         buf_len += snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
 154                         if (type == ENTRY_ROUTE) {
 155                                 buf[buf_len++] = ',';
 156                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 157                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 158                                         buf_len += strlen(&buf[buf_len]);
 159                                 }
 160                                 buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
 161                                 buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
 162                         } else {
 163                                 buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
 164                         }
 165
 166                         if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1)
 167                                 buf_len += snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
 168
 169                         if (type == ENTRY_PREFIX && e[i].priority) {
 170                                 // priority and router are abused for prefix exclusion
 171                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 172                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 173                                 buf_len += strlen(&buf[buf_len]);
 174                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 175                         }
 176                 }
 177                 buf[buf_len++] = ' ';
 178         }
 179
 180         buf[buf_len - 1] = '\0';
 181         putenv(buf);
 182 }
 183
 184
 185 static void search_to_env(const char *name, const uint8_t *start, size_t len)
 186 {
 187         size_t buf_len = strlen(name);
 188         char *buf = realloc(NULL, buf_len + 2 + len);
 189         char *c = mempcpy(buf, name, buf_len);
 190         *c++ = '=';
 191
 192         for (struct odhcp6c_entry *e = (struct odhcp6c_entry*)start;
 193                                 (uint8_t*)e < &start[len] && &e->auxtarget[e->auxlen] <= &start[len];
 194                                 e = (struct odhcp6c_entry*)(&e->auxtarget[e->auxlen])) {
 195                 c = mempcpy(c, e->auxtarget, e->auxlen);
 196                 *c++ = ' ';
 197         }
 198
 199         c[-1] = '\0';
 200         putenv(buf);
 201 }
 202
 203
 204 static void int_to_env(const char *name, int value)
 205 {
 206         size_t len = 12 + strlen(name);
 207         char *buf = realloc(NULL, len);
 208         snprintf(buf, len, "%s=%d", name, value);
 209         putenv(buf);
 210 }
 211
 212
 213 static void s46_to_env_portparams(const uint8_t *data, size_t len, FILE *fp)
 214 {
 215         uint8_t *odata;
 216         uint16_t otype, olen;
 217         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 218                 if (otype == DHCPV6_OPT_S46_PORTPARAMS &&
 219                                 olen == sizeof(struct dhcpv6_s46_portparams)) {
 220                         struct dhcpv6_s46_portparams *params = (void*)odata;
 221                         fprintf(fp, "offset=%d,psidlen=%d,psid=%d,",
 222                                         params->offset, params->psid_len, ntohs(params->psid));
 223                 }
 224         }
 225 }
 226
 227
 228 static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len)
 229 {
 230         const char *name = (state == STATE_S46_MAPE) ? "MAPE" :
 231                         (state == STATE_S46_MAPT) ? "MAPT" : "LW4O6";
 232
 233         if (len == 0)
 234                 return;
 235
 236         char *str;
 237         size_t strsize;
 238
 239         FILE *fp = open_memstream(&str, &strsize);
 240         fputs(name, fp);
 241         fputc('=', fp);
 242
 243         const char *type = (state == STATE_S46_MAPE) ? "map-e" :
 244                         (state == STATE_S46_MAPT) ? "map-t" : "lw4o6";
 245
 246         uint8_t *odata;
 247         uint16_t otype, olen;
 248         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 249                 struct dhcpv6_s46_rule *rule = (struct dhcpv6_s46_rule*)odata;
 250                 struct dhcpv6_s46_v4v6bind *bind = (struct dhcpv6_s46_v4v6bind*)odata;
 251
 252                 if (state != STATE_S46_LW && otype == DHCPV6_OPT_S46_RULE &&
 253                                 olen >= sizeof(struct dhcpv6_s46_rule)) {
 254                         char buf4[INET_ADDRSTRLEN];
 255                         char buf6[INET6_ADDRSTRLEN];
 256                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 257
 258                         size_t prefix6len = rule->prefix6_len;
 259                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 260
 261                         if (olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
 262                                 continue;
 263
 264                         memcpy(&in6, rule->ipv6_prefix, prefix6len);
 265
 266                         inet_ntop(AF_INET, &rule->ipv4_prefix, buf4, sizeof(buf4));
 267                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 268
 269                         if (rule->flags & 1)
 270                                 fputs("fmr,", fp);
 271
 272                         fprintf(fp, "type=%s,ealen=%d,prefix4len=%d,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
 273                                         type, rule->ea_len, rule->prefix4_len, rule->prefix6_len, buf4, buf6);
 274
 275                         s46_to_env_portparams(&rule->ipv6_prefix[prefix6len],
 276                                         olen - sizeof(*rule) - prefix6len, fp);
 277
 278                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 279                                 if (state != STATE_S46_MAPT && otype == DHCPV6_OPT_S46_BR &&
 280                                                 olen == sizeof(struct in6_addr)) {
 281                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 282                                         fprintf(fp, "br=%s,", buf6);
 283                                 } else if (state == STATE_S46_MAPT && otype == DHCPV6_OPT_S46_DMR &&
 284                                                 olen >= sizeof(struct dhcpv6_s46_dmr)) {
 285                                         struct dhcpv6_s46_dmr *dmr = (struct dhcpv6_s46_dmr*)odata;
 286                                         memset(&in6, 0, sizeof(in6));
 287                                         size_t prefix6len = dmr->dmr_prefix6_len;
 288                                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 289
 290                                         if (olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
 291                                                 continue;
 292
 293                                         memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len);
 294                                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 295                                         fprintf(fp, "dmr=%s/%d,", buf6, dmr->dmr_prefix6_len);
 296                                 }
 297                         }
 298                 } else if (state == STATE_S46_LW && otype == DHCPV6_OPT_S46_V4V6BIND &&
 299                                 olen >= sizeof(struct dhcpv6_s46_v4v6bind)) {
 300                         char buf4[INET_ADDRSTRLEN];
 301                         char buf6[INET6_ADDRSTRLEN];
 302                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 303
 304                         size_t prefix6len = bind->bindprefix6_len;
 305                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 306
 307                         if (olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
 308                                 continue;
 309
 310                         memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);
 311
 312                         inet_ntop(AF_INET, &bind->ipv4_address, buf4, sizeof(buf4));
 313                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 314
 315                         fprintf(fp, "type=%s,ipv4address=%s,prefix6len=%d,ipv6prefix=%s,",
 316                                         type, buf4, bind->bindprefix6_len, buf6);
 317
 318                         s46_to_env_portparams(&bind->bind_ipv6_prefix[prefix6len],
 319                                         olen - sizeof(*bind) - prefix6len, fp);
 320
 321                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 322                                 if (otype == DHCPV6_OPT_S46_BR && olen == sizeof(struct in6_addr)) {
 323                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 324                                         fprintf(fp, "br=%s,", buf6);
 325                                 }
 326                         }
 327                 }
 328
 329                 fputc(' ', fp);
 330         }
 331
 332         fclose(fp);
 333         putenv(str);
 334 }
 335
 336
 337 void script_call(const char *status)
 338 {
 339         size_t dns_len, search_len, custom_len, sntp_ip_len, ntp_ip_len, ntp_dns_len;
 340         size_t sip_ip_len, sip_fqdn_len, aftr_name_len, cer_len, addr_len;
 341         size_t s46_mapt_len, s46_mape_len, s46_lw_len, passthru_len;
 342
 343         odhcp6c_expire();
 344
 345         struct in6_addr *addr = odhcp6c_get_state(STATE_SERVER_ADDR, &addr_len);
 346         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 347         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 348         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 349         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 350         struct in6_addr *ntp = odhcp6c_get_state(STATE_NTP_IP, &ntp_ip_len);
 351         uint8_t *ntp_dns = odhcp6c_get_state(STATE_NTP_FQDN, &ntp_dns_len);
 352         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 353         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 354         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 355         struct in6_addr *cer = odhcp6c_get_state(STATE_CER, &cer_len);
 356         uint8_t *s46_mapt = odhcp6c_get_state(STATE_S46_MAPT, &s46_mapt_len);
 357         uint8_t *s46_mape = odhcp6c_get_state(STATE_S46_MAPE, &s46_mape_len);
 358         uint8_t *s46_lw = odhcp6c_get_state(STATE_S46_LW, &s46_lw_len);
 359         uint8_t *passthru = odhcp6c_get_state(STATE_PASSTHRU, &passthru_len);
 360
 361         size_t prefix_len, address_len, ra_pref_len,
 362                 ra_route_len, ra_dns_len, ra_search_len;
 363         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 364         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 365         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 366         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 367         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 368         uint8_t *ra_search = odhcp6c_get_state(STATE_RA_SEARCH, &ra_search_len);
 369
 370         // Don't set environment before forking, because env is leaky.
 371         if (fork() == 0) {
 372                 ipv6_to_env("SERVER", addr, addr_len / sizeof(*addr));
 373                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 374                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 375                 ipv6_to_env("NTP_IP", ntp, ntp_ip_len / sizeof(*ntp));
 376                 fqdn_to_env("NTP_FQDN", ntp_dns, ntp_dns_len);
 377                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 378                 fqdn_to_env("DOMAINS", search, search_len);
 379                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 380                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 381                 ipv6_to_env("CER", cer, cer_len / sizeof(*cer));
 382                 s46_to_env(STATE_S46_MAPE, s46_mape, s46_mape_len);
 383                 s46_to_env(STATE_S46_MAPT, s46_mapt, s46_mapt_len);
 384                 s46_to_env(STATE_S46_LW, s46_lw, s46_lw_len);
 385                 bin_to_env(custom, custom_len);
 386
 387                 if (odhcp6c_is_bound()) {
 388                         entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 389                         entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 390                 }
 391
 392                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 393                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 394                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 395                 search_to_env("RA_DOMAINS", ra_search, ra_search_len);
 396
 397                 int_to_env("RA_HOPLIMIT", ra_conf_hoplimit(0));
 398                 int_to_env("RA_MTU", ra_conf_mtu(0));
 399                 int_to_env("RA_REACHABLE", ra_conf_reachable(0));
 400                 int_to_env("RA_RETRANSMIT", ra_conf_retransmit(0));
 401
 402                 char *buf = malloc(10 + passthru_len * 2);
 403                 strncpy(buf, "PASSTHRU=", 10);
 404                 script_hexlify(&buf[9], passthru, passthru_len);
 405                 putenv(buf);
 406
 407                 argv[2] = (char*)status;
 408                 execv(argv[0], argv);
 409                 _exit(128);
 410         }
 411
 412         // Delete lost prefixes and user opts
 413         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 414 }