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 <resolv.h>
  17 #include <stdlib.h>
  18 #include <string.h>
  19 #include <syslog.h>
  20 #include <signal.h>
  21 #include <unistd.h>
  22 #include <arpa/inet.h>
  23 #include <netinet/in.h>
  24
  25 #include "odhcp6c.h"
  26
  27 static const char hexdigits[] = "0123456789abcdef";
  28 static const int8_t hexvals[] = {
  29     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
  30     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  31     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  32      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
  33     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  34     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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 };
  38
  39
  40
  41 static char *argv[4] = {NULL, NULL, NULL, NULL};
  42 static volatile char *delayed_call = NULL;
  43
  44
  45 int script_init(const char *path, const char *ifname)
  46 {
  47         argv[0] = (char*)path;
  48         argv[1] = (char*)ifname;
  49         return 0;
  50 }
  51
  52
  53 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  54 {
  55         size_t c;
  56         for (c = 0; c < len && src[0] && src[1]; ++c) {
  57                 int8_t x = (int8_t)*src++;
  58                 int8_t y = (int8_t)*src++;
  59                 if (x < 0 || (x = hexvals[x]) < 0
  60                                 || y < 0 || (y = hexvals[y]) < 0)
  61                         return -1;
  62                 dst[c] = x << 4 | y;
  63                 while (((int8_t)*src) < 0 ||
  64                                 (*src && hexvals[(uint8_t)*src] < 0))
  65                         src++;
  66         }
  67
  68         return c;
  69 }
  70
  71
  72 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
  73         for (size_t i = 0; i < len; ++i) {
  74                 *dst++ = hexdigits[src[i] >> 4];
  75                 *dst++ = hexdigits[src[i] & 0x0f];
  76         }
  77         *dst = 0;
  78 }
  79
  80
  81 static void ipv6_to_env(const char *name,
  82                 const struct in6_addr *addr, size_t cnt)
  83 {
  84         size_t buf_len = strlen(name);
  85         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
  86         memcpy(buf, name, buf_len);
  87         buf[buf_len++] = '=';
  88         for (size_t i = 0; i < cnt; ++i) {
  89                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
  90                 buf_len += strlen(&buf[buf_len]);
  91                 buf[buf_len++] = ' ';
  92         }
  93         buf[buf_len - 1] = '\0';
  94         putenv(buf);
  95 }
  96
  97
  98 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
  99 {
 100         size_t buf_len = strlen(name);
 101         size_t buf_size = len + buf_len + 2;
 102         const uint8_t *fqdn_end = fqdn + len;
 103         char *buf = realloc(NULL, len + buf_len + 2);
 104         memcpy(buf, name, buf_len);
 105         buf[buf_len++] = '=';
 106         int l = 1;
 107         while (l > 0 && fqdn < fqdn_end) {
 108                 l = dn_expand(fqdn, fqdn_end, fqdn, &buf[buf_len], buf_size - buf_len);
 109                 fqdn += l;
 110                 buf_len += strlen(&buf[buf_len]);
 111                 buf[buf_len++] = ' ';
 112         }
 113         buf[buf_len - 1] = '\0';
 114         putenv(buf);
 115 }
 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, "/%hhu", 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 && e[i].priority) {
 167                                 // priority and router are abused for prefix exclusion
 168                                 buf_len += snprintf(&buf[buf_len], 12, ",excluded=");
 169                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 170                                 buf_len += strlen(&buf[buf_len]);
 171                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 172                         }
 173                 }
 174                 buf[buf_len++] = ' ';
 175         }
 176
 177         buf[buf_len - 1] = '\0';
 178         putenv(buf);
 179 }
 180
 181
 182 static void script_call_delayed(int signal __attribute__((unused)))
 183 {
 184         if (delayed_call)
 185                 script_call((char*)delayed_call);
 186 }
 187
 188
 189 void script_delay_call(const char *status, int timeout)
 190 {
 191         if (!delayed_call) {
 192                 delayed_call = strdup(status);
 193                 signal(SIGALRM, script_call_delayed);
 194                 alarm(timeout);
 195         }
 196 }
 197
 198
 199 void script_call(const char *status)
 200 {
 201         size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 202         size_t sip_ip_len, sip_fqdn_len, aftr_name_len;
 203
 204         odhcp6c_expire();
 205         if (delayed_call)
 206                 alarm(0);
 207
 208         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 209         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 210         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 211         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 212         uint8_t *sntp_dns = odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 213         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 214         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 215         uint8_t *aftr_name = odhcp6c_get_state(STATE_AFTR_NAME, &aftr_name_len);
 216
 217         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 218         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 219         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 220         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 221         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 222         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 223
 224         // Don't set environment before forking, because env is leaky.
 225         if (fork() == 0) {
 226                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 227                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 228                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 229                 fqdn_to_env("DOMAINS", search, search_len);
 230                 fqdn_to_env("SNTP_FQDN", sntp_dns, sntp_dns_len);
 231                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 232                 fqdn_to_env("AFTR", aftr_name, aftr_name_len);
 233                 bin_to_env(custom, custom_len);
 234                 entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 235                 entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 236                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 237                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 238                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 239
 240                 argv[2] = (char*)status;
 241                 execv(argv[0], argv);
 242                 _exit(128);
 243         }
 244
 245         // Delete lost prefixes and user opts
 246         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 247 }