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 <unistd.h>
  21 #include <arpa/inet.h>
  22 #include <netinet/in.h>
  23
  24 #include "odhcp6c.h"
  25
  26 static const char hexdigits[] = "0123456789abcdef";
  27 static const int8_t hexvals[] = {
  28     -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
  29     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  30     -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  31      0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,
  32     -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
  33     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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 };
  37
  38
  39
  40 static char *argv[4] = {NULL, NULL, NULL, NULL};
  41
  42
  43 int script_init(const char *path, const char *ifname)
  44 {
  45         argv[0] = (char*)path;
  46         argv[1] = (char*)ifname;
  47         return 0;
  48 }
  49
  50
  51 ssize_t script_unhexlify(uint8_t *dst, size_t len, const char *src)
  52 {
  53         size_t c;
  54         for (c = 0; c < len && src[0] && src[1]; ++c) {
  55                 int8_t x = (int8_t)*src++;
  56                 int8_t y = (int8_t)*src++;
  57                 if (x < 0 || (x = hexvals[x]) < 0
  58                                 || y < 0 || (y = hexvals[y]) < 0)
  59                         return -1;
  60                 dst[c] = x << 4 | y;
  61                 while (((int8_t)*src) < 0 ||
  62                                 (*src && hexvals[(uint8_t)*src] < 0))
  63                         src++;
  64         }
  65
  66         return c;
  67 }
  68
  69
  70 static void script_hexlify(char *dst, const uint8_t *src, size_t len) {
  71         for (size_t i = 0; i < len; ++i) {
  72                 *dst++ = hexdigits[src[i] >> 4];
  73                 *dst++ = hexdigits[src[i] & 0x0f];
  74         }
  75         *dst = 0;
  76 }
  77
  78
  79 static void ipv6_to_env(const char *name,
  80                 const struct in6_addr *addr, size_t cnt)
  81 {
  82         size_t buf_len = strlen(name);
  83         char *buf = realloc(NULL, cnt * INET6_ADDRSTRLEN + buf_len + 2);
  84         memcpy(buf, name, buf_len);
  85         buf[buf_len++] = '=';
  86         for (size_t i = 0; i < cnt; ++i) {
  87                 inet_ntop(AF_INET6, &addr[i], &buf[buf_len], INET6_ADDRSTRLEN);
  88                 buf_len += strlen(&buf[buf_len]);
  89                 buf[buf_len++] = ' ';
  90         }
  91         buf[buf_len - 1] = '\0';
  92         putenv(buf);
  93 }
  94
  95
  96 static void fqdn_to_env(const char *name, const uint8_t *fqdn, size_t len)
  97 {
  98         size_t buf_len = strlen(name);
  99         const uint8_t *fqdn_end = fqdn + len;
 100         char *buf = realloc(NULL, len + buf_len + 2);
 101         memcpy(buf, name, buf_len);
 102         buf[buf_len++] = '=';
 103         int l = 1;
 104         while (l > 0 && fqdn < fqdn_end) {
 105                 l = dn_expand(fqdn, &fqdn[len], fqdn, &buf[buf_len], len);
 106                 fqdn += l;
 107                 buf_len += strlen(&buf[buf_len]);
 108                 buf[buf_len++] = ' ';
 109         }
 110         buf[buf_len - 1] = '\0';
 111         putenv(buf);
 112 }
 113
 114
 115 static void bin_to_env(uint8_t *opts, size_t len)
 116 {
 117         uint8_t *oend = opts + len, *odata;
 118         uint16_t otype, olen;
 119         dhcpv6_for_each_option(opts, oend, otype, olen, odata) {
 120                 char *buf = realloc(NULL, 14 + (olen * 2));
 121                 size_t buf_len = 0;
 122
 123                 snprintf(buf, 14, "OPTION_%hu=", otype);
 124                 buf_len += strlen(buf);
 125
 126                 script_hexlify(&buf[buf_len], odata, olen);
 127                 putenv(buf);
 128         }
 129 }
 130
 131 enum entry_type {
 132         ENTRY_ADDRESS,
 133         ENTRY_HOST,
 134         ENTRY_ROUTE,
 135         ENTRY_PREFIX
 136 };
 137
 138 static void entry_to_env(const char *name, const void *data, size_t len, enum entry_type type)
 139 {
 140         size_t buf_len = strlen(name);
 141         const struct odhcp6c_entry *e = data;
 142         char *buf = realloc(NULL, buf_len + 2 + (len / sizeof(*e)) * 144);
 143         memcpy(buf, name, buf_len);
 144         buf[buf_len++] = '=';
 145
 146         for (size_t i = 0; i < len / sizeof(*e); ++i) {
 147                 inet_ntop(AF_INET6, &e[i].target, &buf[buf_len], INET6_ADDRSTRLEN);
 148                 buf_len += strlen(&buf[buf_len]);
 149                 if (type != ENTRY_HOST) {
 150                         buf_len += snprintf(&buf[buf_len], 6, "/%hhu", e[i].length);
 151                         if (type == ENTRY_ROUTE) {
 152                                 buf[buf_len++] = ',';
 153                                 if (!IN6_IS_ADDR_UNSPECIFIED(&e[i].router)) {
 154                                         inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 155                                         buf_len += strlen(&buf[buf_len]);
 156                                 }
 157                                 buf_len += snprintf(&buf[buf_len], 24, ",%u", e[i].valid);
 158                                 buf_len += snprintf(&buf[buf_len], 12, ",%u", e[i].priority);
 159                         } else {
 160                                 buf_len += snprintf(&buf[buf_len], 24, ",%u,%u", e[i].preferred, e[i].valid);
 161                         }
 162
 163                         if (type == ENTRY_PREFIX && e[i].priority) {
 164                                 // priority and router are abused for prefix exclusion
 165                                 buf[buf_len++] = ',';
 166                                 inet_ntop(AF_INET6, &e[i].router, &buf[buf_len], INET6_ADDRSTRLEN);
 167                                 buf_len += strlen(&buf[buf_len]);
 168                                 buf_len += snprintf(&buf[buf_len], 24, "/%u", e[i].priority);
 169                         }
 170                 }
 171                 buf[buf_len++] = ' ';
 172         }
 173
 174         buf[buf_len - 1] = '\0';
 175         putenv(buf);
 176 }
 177
 178
 179 void script_call(const char *status)
 180 {
 181         size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 182         size_t sip_ip_len, sip_fqdn_len;
 183
 184         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 185         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 186         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 187         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 188         uint8_t *sntp_dns = odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 189         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 190         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 191
 192         size_t prefix_len, address_len, ra_pref_len, ra_route_len, ra_dns_len;
 193         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 194         uint8_t *address = odhcp6c_get_state(STATE_IA_NA, &address_len);
 195         uint8_t *ra_pref = odhcp6c_get_state(STATE_RA_PREFIX, &ra_pref_len);
 196         uint8_t *ra_route = odhcp6c_get_state(STATE_RA_ROUTE, &ra_route_len);
 197         uint8_t *ra_dns = odhcp6c_get_state(STATE_RA_DNS, &ra_dns_len);
 198
 199         // Don't set environment before forking, because env is leaky.
 200         if (fork() == 0) {
 201                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 202                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 203                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 204                 fqdn_to_env("DOMAINS", search, search_len);
 205                 fqdn_to_env("SNTP_FQDN", sntp_dns, sntp_dns_len);
 206                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 207                 bin_to_env(custom, custom_len);
 208                 entry_to_env("PREFIXES", prefix, prefix_len, ENTRY_PREFIX);
 209                 entry_to_env("ADDRESSES", address, address_len, ENTRY_ADDRESS);
 210                 entry_to_env("RA_ADDRESSES", ra_pref, ra_pref_len, ENTRY_ADDRESS);
 211                 entry_to_env("RA_ROUTES", ra_route, ra_route_len, ENTRY_ROUTE);
 212                 entry_to_env("RA_DNS", ra_dns, ra_dns_len, ENTRY_HOST);
 213
 214                 argv[2] = (char*)status;
 215                 execv(argv[0], argv);
 216                 _exit(128);
 217         }
 218
 219         // Delete lost prefixes and user opts
 220         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 221 }