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 static volatile char *delayed_call = NULL;
  45 static bool dont_delay = false;
  46
  47
  48 int script_init(const char *path, const char *ifname)
  49 {
  50         argv[0] = (char*)path;
  51         argv[1] = (char*)ifname;
  52         return 0;
  53 }
  54
  55
  56 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  57 {
  58         size_t c;
  59         for (c = 0; c < len && src[0] && src[1]; ++c) {
  60                 int8_t x = (int8_t)*src++;
  61                 int8_t y = (int8_t)*src++;
  62                 if (x < 0 || (x = hexvals[x]) < 0
  63                                 || y < 0 || (y = hexvals[y]) < 0)
  64                         return -1;
  65                 dst[c] = x << 4 | y;
  66                 while (((int8_t)*src) < 0 ||
  67                                 (*src && hexvals[(uint8_t)*src] < 0))
  68                         src++;
  69         }
  70
  71         return c;
  72 }
  73
  74
  75 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
  76         for (size_t i = 0; i < len; ++i) {
  77                 *dst++ = hexdigits[src[i] >> 4];
  78                 *dst++ = hexdigits[src[i] & 0x0f];
  79         }
  80         *dst = 0;
  81 }
  82
  83
  84 static void ipv6_to_env(const char *name,
  85                 const struct in6_addr *addr, size_t cnt)
  86 {
  87         size_t buf_len = strlen(name);
  88         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
  89         memcpy(buf, name, buf_len);
  90         buf[buf_len++] = '=';
  91         for (size_t i = 0; i < cnt; ++i) {
  92                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
  93                 buf_len += strlen(&buf[buf_len]);
  94                 buf[buf_len++] = ' ';
  95         }
  96         buf[buf_len - 1] = '\0';
  97         putenv(buf);
  98 }
  99
 100
 101 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
 102 {
 103         size_t buf_len = strlen(name);
 104         size_t buf_size = len + buf_len + 2;
 105         const uint8_t *fqdn_end = fqdn + len;
 106         char *buf = realloc(NULL, len + buf_len + 2);
 107         memcpy(buf, name, buf_len);
 108         buf[buf_len++] = '=';
 109         int l = 1;
 110         while (l > 0 && fqdn < fqdn_end) {
 111                 l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
 112                 fqdn += l;
 113                 buf_len += strlen(&buf[buf_len]);
 114                 buf[buf_len++] = ' ';
 115         }
 116         buf[buf_len - 1] = '\0';
 117         putenv(buf);
 118 }
 119
 120
 121 static void fqdn_to_ip_env(const char *name, const uint8_t *fqdn, size_t len)
 122 {
 123         size_t buf_len = strlen(name);
 124         char *buf = realloc(NULL, INET6_ADDRSTRLEN + buf_len + 3);
 125         memcpy(buf, name, buf_len);
 126         buf[buf_len++] = '=';
 127
 128         char namebuf[256];
 129         if (dn_expand(fqdn, fqdn + len, fqdn, namebuf, sizeof(namebuf)) <= 0)
 130                 return;
 131
 132         struct addrinfo hints = {.ai_family = AF_INET6}, *r;
 133         if (getaddrinfo(namebuf, NULL, &hints, &r))
 134                 return;
 135
 136         struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)r->ai_addr;
 137         inet_ntop(AF_INET6, &sin6->sin6_addr, &buf[buf_len], INET6_ADDRSTRLEN);
 138
 139         freeaddrinfo(r);
 140         putenv(buf);
 141 }
 142
 143
 144 static void bin_to_env(uint8_t *opts, size_t len)
 145 {
 146         uint8_t *oend = opts + len, *odata;
 147         uint16_t otype, olen;
 148         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 149                 char *buf = realloc(NULL, 14 + (olen * 2));
 150                 size_t buf_len = 0;
 151
 152                 snprintf(buf, 14, "OPTION_%hu=", otype);
 153                 buf_len += strlen(buf);
 154
 155                 script_hexlify(&buf[buf_len], odata, olen);
 156                 putenv(buf);
 157         }
 158 }
 159
 160 enum entry_type {
 161         ENTRY_ADDRESS,
 162         ENTRY_HOST,
 163         ENTRY_ROUTE,
 164         ENTRY_PREFIX
 165 };
 166
 167 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 168 {
 169         size_t buf_len = strlen(name);
 170         const struct odhcp6c_entry *e = data;
 171         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
 172         memcpy(buf, name, buf_len);
 173         buf[buf_len++] = '=';
 174
 175         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 176                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 177                 buf_len += strlen(&buf[buf_len]);
 178                 if (type != ENTRY_HOST) {
 179                         buf_len += snprintf(&buf[buf_len], 6, "/%"PRIu16, e[i].length);
 180                         if (type == ENTRY_ROUTE) {
 181                                 buf[buf_len++] = ',';
 182                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 183                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 184                                         buf_len += strlen(&buf[buf_len]);
 185                                 }
 186                                 buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
 187                                 buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
 188                         } else {
 189                                 buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
 190                         }
 191
 192                         if ((type == ENTRY_PREFIX || type == ENTRY_ADDRESS) && e[i].class)
 193                                 buf_len += snprintf(&buf[buf_len], 12, ",class=%u", e[i].class);
 194                         else if (type == ENTRY_PREFIX && ntohl(e[i].iaid) != 1)
 195                                 buf_len += snprintf(&buf[buf_len], 16, ",class=%08x", ntohl(e[i].iaid));
 196
 197                         if (type == ENTRY_PREFIX && e[i].priority) {
 198                                 // priority and router are abused for prefix exclusion
 199                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 200                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 201                                 buf_len += strlen(&buf[buf_len]);
 202                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 203                         }
 204                 }
 205                 buf[buf_len++] = ' ';
 206         }
 207
 208         buf[buf_len - 1] = '\0';
 209         putenv(buf);
 210 }
 211
 212
 213 static void script_call_delayed(int signal __attribute__((unused)))
 214 {
 215         if (delayed_call)
 216                 script_call((char*)delayed_call);
 217 }
 218
 219
 220 void script_delay_call(const char *status, int timeout)
 221 {
 222         if (dont_delay) {
 223                 script_call(status);
 224         } else if (!delayed_call) {
 225                 delayed_call = strdup(status);
 226                 signal(SIGALRM, script_call_delayed);
 227                 alarm(timeout);
 228         }
 229 }
 230
 231
 232 void script_call(const char *status)
 233 {
 234         size_t dns_len, search_len, custom_len, sntp_ip_len, ntp_ip_len, ntp_dns_len;
 235         size_t sip_ip_len, sip_fqdn_len, aftr_name_len;
 236
 237         odhcp6c_expire();
 238         if (delayed_call) {
 239                 alarm(0);
 240                 dont_delay = true;
 241         }
 242
 243         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 244         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 245         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 246         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 247         struct in6_addr *ntp = odhcp6c_get_state(STATE_NTP_IP, &ntp_ip_len);
 248         uint8_t *ntp_dns = odhcp6c_get_state(STATE_NTP_FQDN, &ntp_dns_len);
 249         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 250         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 251         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 252
 253         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 254         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 255         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 256         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 257         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 258         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 259
 260         // Don't set environment before forking, because env is leaky.
 261         if (fork() == 0) {
 262                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 263                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 264                 ipv6_to_env("NTP_IP", ntp, ntp_ip_len / sizeof(*ntp));
 265                 fqdn_to_env("NTP_FQDN", ntp_dns, ntp_dns_len);
 266                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 267                 fqdn_to_env("DOMAINS", search, search_len);
 268                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 269                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 270                 fqdn_to_ip_env("AFTR_IP", aftr_name, aftr_name_len);
 271                 bin_to_env(custom, custom_len);
 272                 entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 273                 entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 274                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 275                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 276                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 277
 278                 argv[2] = (char*)status;
 279                 execv(argv[0], argv);
 280                 _exit(128);
 281         }
 282
 283         // Delete lost prefixes and user opts
 284         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 285 }