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
  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
 119 static void fqdn_to_ip_env(const char *name, const uint8_t *fqdn, size_t len)
 120 {
 121         size_t buf_len = strlen(name);
 122         char *buf = realloc(NULL, INET6_ADDRSTRLEN + buf_len + 3);
 123         memcpy(buf, name, buf_len);
 124         buf[buf_len++] = '=';
 125
 126         char namebuf[256];
 127         if (dn_expand(fqdn, fqdn + len, fqdn, namebuf, sizeof(namebuf)) <= 0)
 128                 return;
 129
 130         struct addrinfo hints = {.ai_family = AF_INET6}, *r;
 131         if (getaddrinfo(namebuf, NULL, &hints, &r))
 132                 return;
 133
 134         struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)r->ai_addr;
 135         inet_ntop(AF_INET6, &sin6->sin6_addr, &buf[buf_len], INET6_ADDRSTRLEN);
 136
 137         freeaddrinfo(r);
 138         putenv(buf);
 139 }
 140
 141
 142 static void bin_to_env(uint8_t *opts, size_t len)
 143 {
 144         uint8_t *oend = opts + len, *odata;
 145         uint16_t otype, olen;
 146         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 147                 char *buf = realloc(NULL, 14 + (olen * 2));
 148                 size_t buf_len = 0;
 149
 150                 snprintf(buf, 14, "OPTION_%hu=", otype);
 151                 buf_len += strlen(buf);
 152
 153                 script_hexlify(&buf[buf_len], odata, olen);
 154                 putenv(buf);
 155         }
 156 }
 157
 158 enum entry_type {
 159         ENTRY_ADDRESS,
 160         ENTRY_HOST,
 161         ENTRY_ROUTE,
 162         ENTRY_PREFIX
 163 };
 164
 165 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 166 {
 167         size_t buf_len = strlen(name);
 168         const struct odhcp6c_entry *e = data;
 169         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
 170         memcpy(buf, name, buf_len);
 171         buf[buf_len++] = '=';
 172
 173         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 174                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 175                 buf_len += strlen(&buf[buf_len]);
 176                 if (type != ENTRY_HOST) {
 177                         buf_len += snprintf(&buf[buf_len], 6, "/%hhu", e[i].length);
 178                         if (type == ENTRY_ROUTE) {
 179                                 buf[buf_len++] = ',';
 180                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 181                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 182                                         buf_len += strlen(&buf[buf_len]);
 183                                 }
 184                                 buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
 185                                 buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
 186                         } else {
 187                                 buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
 188                         }
 189
 190                         if (type == ENTRY_PREFIX && e[i].priority) {
 191                                 // priority and router are abused for prefix exclusion
 192                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 193                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 194                                 buf_len += strlen(&buf[buf_len]);
 195                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 196                         }
 197                 }
 198                 buf[buf_len++] = ' ';
 199         }
 200
 201         buf[buf_len - 1] = '\0';
 202         putenv(buf);
 203 }
 204
 205
 206 static void script_call_delayed(int signal __attribute__((unused)))
 207 {
 208         if (delayed_call)
 209                 script_call((char*)delayed_call);
 210 }
 211
 212
 213 void script_delay_call(const char *status, int timeout)
 214 {
 215         if (!delayed_call) {
 216                 delayed_call = strdup(status);
 217                 signal(SIGALRM, script_call_delayed);
 218                 alarm(timeout);
 219         }
 220 }
 221
 222
 223 void script_call(const char *status)
 224 {
 225         size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 226         size_t sip_ip_len, sip_fqdn_len, aftr_name_len;
 227
 228         odhcp6c_expire();
 229         if (delayed_call)
 230                 alarm(0);
 231
 232         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 233         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 234         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 235         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 236         uint8_t *sntp_dns = odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 237         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 238         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 239         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 240
 241         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 242         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 243         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 244         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 245         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 246         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 247
 248         // Don't set environment before forking, because env is leaky.
 249         if (fork() == 0) {
 250                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 251                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 252                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 253                 fqdn_to_env("DOMAINS", search, search_len);
 254                 fqdn_to_env("SNTP_FQDN", sntp_dns, sntp_dns_len);
 255                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 256                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 257                 fqdn_to_ip_env("AFTR_IP", aftr_name, aftr_name_len);
 258                 bin_to_env(custom, custom_len);
 259                 entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 260                 entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 261                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 262                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 263                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 264
 265                 argv[2] = (char*)status;
 266                 execv(argv[0], argv);
 267                 _exit(128);
 268         }
 269
 270         // Delete lost prefixes and user opts
 271         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 272 }