src/script.c

   1 /**
   2  * Copyright (C) 2012-2013 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 <arpa/inet.h>
  24 #include <netinet/in.h>
  25
  26 #include "odhcp6c.h"
  27
  28 static const char hexdigits[] = "0123456789abcdef";
  29 static const int8_t hexvals[] = {
  30     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
  31     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  32     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  33      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
  34     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  35     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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 };
  39
  40
  41
  42 static char *argv[4] = {NULL, NULL, NULL, NULL};
  43 static volatile char *delayed_call = NULL;
  44 static bool dont_delay = false;
  45
  46
  47 int script_init(const char *path, const char *ifname)
  48 {
  49         argv[0] = (char*)path;
  50         argv[1] = (char*)ifname;
  51         return 0;
  52 }
  53
  54
  55 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  56 {
  57         size_t c;
  58         for (c = 0; c < len && src[0] && src[1]; ++c) {
  59                 int8_t x = (int8_t)*src++;
  60                 int8_t y = (int8_t)*src++;
  61                 if (x < 0 || (x = hexvals[x]) < 0
  62                                 || y < 0 || (y = hexvals[y]) < 0)
  63                         return -1;
  64                 dst[c] = x << 4 | y;
  65                 while (((int8_t)*src) < 0 ||
  66                                 (*src && hexvals[(uint8_t)*src] < 0))
  67                         src++;
  68         }
  69
  70         return c;
  71 }
  72
  73
  74 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
  75         for (size_t i = 0; i < len; ++i) {
  76                 *dst++ = hexdigits[src[i] >> 4];
  77                 *dst++ = hexdigits[src[i] & 0x0f];
  78         }
  79         *dst = 0;
  80 }
  81
  82
  83 static void ipv6_to_env(const char *name,
  84                 const struct in6_addr *addr, size_t cnt)
  85 {
  86         size_t buf_len = strlen(name);
  87         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
  88         memcpy(buf, name, buf_len);
  89         buf[buf_len++] = '=';
  90         for (size_t i = 0; i < cnt; ++i) {
  91                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
  92                 buf_len += strlen(&buf[buf_len]);
  93                 buf[buf_len++] = ' ';
  94         }
  95         buf[buf_len - 1] = '\0';
  96         putenv(buf);
  97 }
  98
  99
 100 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
 101 {
 102         size_t buf_len = strlen(name);
 103         size_t buf_size = len + buf_len + 2;
 104         const uint8_t *fqdn_end = fqdn + len;
 105         char *buf = realloc(NULL, len + buf_len + 2);
 106         memcpy(buf, name, buf_len);
 107         buf[buf_len++] = '=';
 108         int l = 1;
 109         while (l > 0 && fqdn < fqdn_end) {
 110                 l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
 111                 fqdn += l;
 112                 buf_len += strlen(&buf[buf_len]);
 113                 buf[buf_len++] = ' ';
 114         }
 115         buf[buf_len - 1] = '\0';
 116         putenv(buf);
 117 }
 118
 119
 120 static void fqdn_to_ip_env(const char *name, const uint8_t *fqdn, size_t len)
 121 {
 122         size_t buf_len = strlen(name);
 123         char *buf = realloc(NULL, INET6_ADDRSTRLEN + buf_len + 3);
 124         memcpy(buf, name, buf_len);
 125         buf[buf_len++] = '=';
 126
 127         char namebuf[256];
 128         if (dn_expand(fqdn, fqdn + len, fqdn, namebuf, sizeof(namebuf)) <= 0)
 129                 return;
 130
 131         struct addrinfo hints = {.ai_family = AF_INET6}, *r;
 132         if (getaddrinfo(namebuf, NULL, &hints, &r))
 133                 return;
 134
 135         struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)r->ai_addr;
 136         inet_ntop(AF_INET6, &sin6->sin6_addr, &buf[buf_len], INET6_ADDRSTRLEN);
 137
 138         freeaddrinfo(r);
 139         putenv(buf);
 140 }
 141
 142
 143 static void bin_to_env(uint8_t *opts, size_t len)
 144 {
 145         uint8_t *oend = opts + len, *odata;
 146         uint16_t otype, olen;
 147         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 148                 char *buf = realloc(NULL, 14 + (olen * 2));
 149                 size_t buf_len = 0;
 150
 151                 snprintf(buf, 14, "OPTION_%hu=", otype);
 152                 buf_len += strlen(buf);
 153
 154                 script_hexlify(&buf[buf_len], odata, olen);
 155                 putenv(buf);
 156         }
 157 }
 158
 159 enum entry_type {
 160         ENTRY_ADDRESS,
 161         ENTRY_HOST,
 162         ENTRY_ROUTE,
 163         ENTRY_PREFIX
 164 };
 165
 166 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 167 {
 168         size_t buf_len = strlen(name);
 169         const struct odhcp6c_entry *e = data;
 170         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
 171         memcpy(buf, name, buf_len);
 172         buf[buf_len++] = '=';
 173
 174         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 175                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 176                 buf_len += strlen(&buf[buf_len]);
 177                 if (type != ENTRY_HOST) {
 178                         buf_len += snprintf(&buf[buf_len], 6, "/%hhu", e[i].length);
 179                         if (type == ENTRY_ROUTE) {
 180                                 buf[buf_len++] = ',';
 181                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 182                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 183                                         buf_len += strlen(&buf[buf_len]);
 184                                 }
 185                                 buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
 186                                 buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
 187                         } else {
 188                                 buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
 189                         }
 190
 191                         if (type == ENTRY_PREFIX && e[i].priority) {
 192                                 // priority and router are abused for prefix exclusion
 193                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 194                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 195                                 buf_len += strlen(&buf[buf_len]);
 196                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 197                         }
 198                 }
 199                 buf[buf_len++] = ' ';
 200         }
 201
 202         buf[buf_len - 1] = '\0';
 203         putenv(buf);
 204 }
 205
 206
 207 static void script_call_delayed(int signal __attribute__((unused)))
 208 {
 209         if (delayed_call)
 210                 script_call((char*)delayed_call);
 211 }
 212
 213
 214 void script_delay_call(const char *status, int timeout)
 215 {
 216         if (dont_delay) {
 217                 script_call(status);
 218         } else if (!delayed_call) {
 219                 delayed_call = strdup(status);
 220                 signal(SIGALRM, script_call_delayed);
 221                 alarm(timeout);
 222         }
 223 }
 224
 225
 226 void script_call(const char *status)
 227 {
 228         size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 229         size_t sip_ip_len, sip_fqdn_len, aftr_name_len;
 230
 231         odhcp6c_expire();
 232         if (delayed_call) {
 233                 alarm(0);
 234                 dont_delay = true;
 235         }
 236
 237         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 238         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 239         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 240         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 241         uint8_t *sntp_dns = odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 242         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 243         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 244         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 245
 246         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 247         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 248         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 249         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 250         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 251         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 252
 253         // Don't set environment before forking, because env is leaky.
 254         if (fork() == 0) {
 255                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 256                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 257                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 258                 fqdn_to_env("DOMAINS", search, search_len);
 259                 fqdn_to_env("SNTP_FQDN", sntp_dns, sntp_dns_len);
 260                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 261                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 262                 fqdn_to_ip_env("AFTR_IP", aftr_name, aftr_name_len);
 263                 bin_to_env(custom, custom_len);
 264                 entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 265                 entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 266                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 267                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 268                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 269
 270                 argv[2] = (char*)status;
 271                 execv(argv[0], argv);
 272                 _exit(128);
 273         }
 274
 275         // Delete lost prefixes and user opts
 276         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 277 }