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 || type == ENTRY_ADDRESS) && e[i].class)
 167                                 buf_len += snprintf(&buf[buf_len], 12, ",class=%u", e[i].class);
 168                         else if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1)
 169                                 buf_len += snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
 170
 171                         if (type == ENTRY_PREFIX && e[i].priority) {
 172                                 // priority and router are abused for prefix exclusion
 173                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 174                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 175                                 buf_len += strlen(&buf[buf_len]);
 176                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 177                         }
 178                 }
 179                 buf[buf_len++] = ' ';
 180         }
 181
 182         buf[buf_len - 1] = '\0';
 183         putenv(buf);
 184 }
 185
 186
 187 static void int_to_env(const char *name, int value)
 188 {
 189         size_t len = 12 + strlen(name);
 190         char *buf = realloc(NULL, len);
 191         snprintf(buf, len, "%s=%d", name, value);
 192         putenv(buf);
 193 }
 194
 195
 196 static void s46_to_env_portparams(const uint8_t *data, size_t len, FILE *fp)
 197 {
 198         uint8_t *odata;
 199         uint16_t otype, olen;
 200         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 201                 if (otype == DHCPV6_OPT_S46_PORTPARAMS &&
 202                                 olen == sizeof(struct dhcpv6_s46_portparams)) {
 203                         struct dhcpv6_s46_portparams *params = (void*)odata;
 204                         fprintf(fp, "offset=%d,psidlen=%d,psid=%d,",
 205                                         params->offset, params->psid_len, ntohs(params->psid));
 206                 }
 207         }
 208 }
 209
 210
 211 static void s46_to_env(enum odhcp6c_state state, const uint8_t *data, size_t len)
 212 {
 213         const char *name = (state == STATE_S46_MAPE) ? "MAPE" :
 214                         (state == STATE_S46_MAPT) ? "MAPT" : "LW4O6";
 215
 216         if (len == 0)
 217                 return;
 218
 219         char *str;
 220         size_t strsize;
 221
 222         FILE *fp = open_memstream(&str, &strsize);
 223         fputs(name, fp);
 224         fputc('=', fp);
 225
 226         const char *type = (state == STATE_S46_MAPE) ? "map-e" :
 227                         (state == STATE_S46_MAPT) ? "map-t" : "lw4o6";
 228
 229         uint8_t *odata;
 230         uint16_t otype, olen;
 231         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 232                 struct dhcpv6_s46_rule *rule = (struct dhcpv6_s46_rule*)odata;
 233                 struct dhcpv6_s46_dmr *dmr = (struct dhcpv6_s46_dmr*)odata;
 234                 struct dhcpv6_s46_v4v6bind *bind = (struct dhcpv6_s46_v4v6bind*)odata;
 235
 236                 if (state != STATE_S46_LW && otype == DHCPV6_OPT_S46_RULE &&
 237                                 olen >= sizeof(struct dhcpv6_s46_rule)) {
 238                         char buf4[INET_ADDRSTRLEN];
 239                         char buf6[INET6_ADDRSTRLEN];
 240                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 241
 242                         size_t prefix6len = rule->prefix6_len;
 243                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 244
 245                         if (olen < sizeof(struct dhcpv6_s46_rule) + prefix6len)
 246                                 continue;
 247
 248                         memcpy(&in6, rule->ipv6_prefix, prefix6len);
 249
 250                         inet_ntop(AF_INET, &rule->ipv4_prefix, buf4, sizeof(buf4));
 251                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 252
 253                         if (rule->flags & 1)
 254                                 fputs("fmr,", fp);
 255
 256                         fprintf(fp, "type=%s,ealen=%d,prefix4len=%d,prefix6len=%d,ipv4prefix=%s,ipv6prefix=%s,",
 257                                         type, rule->ea_len, rule->prefix4_len, rule->prefix6_len, buf4, buf6);
 258
 259                         s46_to_env_portparams(&rule->ipv6_prefix[prefix6len],
 260                                         olen - sizeof(*rule) - prefix6len, fp);
 261
 262                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 263                                 if (state != STATE_S46_MAPT && otype == DHCPV6_OPT_S46_BR &&
 264                                                 olen == sizeof(struct in6_addr)) {
 265                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 266                                         fprintf(fp, "br=%s,", buf6);
 267                                 } else if (state == STATE_S46_MAPT && otype == DHCPV6_OPT_S46_DMR &&
 268                                                 olen >= sizeof(struct dhcpv6_s46_dmr)) {
 269                                         dmr = (struct dhcpv6_s46_dmr*)odata;
 270                                         memset(&in6, 0, sizeof(in6));
 271                                         size_t prefix6len = dmr->dmr_prefix6_len;
 272                                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 273
 274                                         if (olen < sizeof(struct dhcpv6_s46_dmr) + prefix6len)
 275                                                 continue;
 276
 277                                         memcpy(&in6, dmr->dmr_ipv6_prefix, prefix6len);
 278                                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 279                                         fprintf(fp, "dmr=%s/%d,", buf6, dmr->dmr_prefix6_len);
 280                                 }
 281                         }
 282                 } else if (state == STATE_S46_LW && otype == DHCPV6_OPT_S46_V4V6BIND &&
 283                                 olen >= sizeof(struct dhcpv6_s46_v4v6bind)) {
 284                         char buf4[INET_ADDRSTRLEN];
 285                         char buf6[INET6_ADDRSTRLEN];
 286                         struct in6_addr in6 = IN6ADDR_ANY_INIT;
 287
 288                         size_t prefix6len = bind->bindprefix6_len;
 289                         prefix6len = (prefix6len % 8 == 0) ? prefix6len / 8 : prefix6len / 8 + 1;
 290
 291                         if (olen < sizeof(struct dhcpv6_s46_v4v6bind) + prefix6len)
 292                                 continue;
 293
 294                         memcpy(&in6, bind->bind_ipv6_prefix, prefix6len);
 295
 296                         inet_ntop(AF_INET, &bind->ipv4_address, buf4, sizeof(buf4));
 297                         inet_ntop(AF_INET6, &in6, buf6, sizeof(buf6));
 298
 299                         fprintf(fp, "type=%s,ipv4address=%s,prefix6len=%d,ipv6prefix=%s,",
 300                                         type, buf4, bind->bindprefix6_len, buf6);
 301
 302                         s46_to_env_portparams(&bind->bind_ipv6_prefix[prefix6len],
 303                                         olen - sizeof(*bind) - prefix6len, fp);
 304
 305                         dhcpv6_for_each_option(data, &data[len], otype, olen, odata) {
 306                                 if (otype == DHCPV6_OPT_S46_BR && olen == sizeof(struct in6_addr)) {
 307                                         inet_ntop(AF_INET6, odata, buf6, sizeof(buf6));
 308                                         fprintf(fp, "br=%s,", buf6);
 309                                 }
 310                         }
 311                 }
 312
 313                 fputc(' ', fp);
 314         }
 315
 316         fclose(fp);
 317         putenv(str);
 318 }
 319
 320
 321 void script_call(const char *status)
 322 {
 323         size_t dns_len, search_len, custom_len, sntp_ip_len, ntp_ip_len, ntp_dns_len;
 324         size_t sip_ip_len, sip_fqdn_len, aftr_name_len, cer_len, addr_len;
 325         size_t s46_mapt_len, s46_mape_len, s46_lw_len, passthru_len;
 326
 327         odhcp6c_expire();
 328
 329         struct in6_addr *addr = odhcp6c_get_state(STATE_SERVER_ADDR, &addr_len);
 330         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 331         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 332         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 333         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 334         struct in6_addr *ntp = odhcp6c_get_state(STATE_NTP_IP, &ntp_ip_len);
 335         uint8_t *ntp_dns = odhcp6c_get_state(STATE_NTP_FQDN, &ntp_dns_len);
 336         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 337         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 338         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 339         struct in6_addr *cer = odhcp6c_get_state(STATE_CER, &cer_len);
 340         uint8_t *s46_mapt = odhcp6c_get_state(STATE_S46_MAPT, &s46_mapt_len);
 341         uint8_t *s46_mape = odhcp6c_get_state(STATE_S46_MAPE, &s46_mape_len);
 342         uint8_t *s46_lw = odhcp6c_get_state(STATE_S46_LW, &s46_lw_len);
 343         uint8_t *passthru = odhcp6c_get_state(STATE_PASSTHRU, &passthru_len);
 344
 345         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 346         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 347         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 348         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 349         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 350         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 351
 352         // Don't set environment before forking, because env is leaky.
 353         if (fork() == 0) {
 354                 ipv6_to_env("SERVER", addr, addr_len / sizeof(*addr));
 355                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 356                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 357                 ipv6_to_env("NTP_IP", ntp, ntp_ip_len / sizeof(*ntp));
 358                 fqdn_to_env("NTP_FQDN", ntp_dns, ntp_dns_len);
 359                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 360                 fqdn_to_env("DOMAINS", search, search_len);
 361                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 362                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 363                 ipv6_to_env("CER", cer, cer_len / sizeof(*cer));
 364                 s46_to_env(STATE_S46_MAPE, s46_mape, s46_mape_len);
 365                 s46_to_env(STATE_S46_MAPT, s46_mapt, s46_mapt_len);
 366                 s46_to_env(STATE_S46_LW, s46_lw, s46_lw_len);
 367                 bin_to_env(custom, custom_len);
 368
 369                 if (odhcp6c_is_bound()) {
 370                         entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 371                         entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 372                 }
 373
 374                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 375                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 376                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 377
 378                 int_to_env("RA_HOPLIMIT", ra_conf_hoplimit(0));
 379                 int_to_env("RA_MTU", ra_conf_mtu(0));
 380                 int_to_env("RA_REACHABLE", ra_conf_reachable(0));
 381                 int_to_env("RA_RETRANSMIT", ra_conf_retransmit(0));
 382
 383                 char *buf = malloc(10 + passthru_len * 2);
 384                 strncpy(buf, "PASSTHRU=", 10);
 385                 script_hexlify(&buf[9], passthru, passthru_len);
 386                 putenv(buf);
 387
 388                 argv[2] = (char*)status;
 389                 execv(argv[0], argv);
 390                 _exit(128);
 391         }
 392
 393         // Delete lost prefixes and user opts
 394         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 395 }