src/script.c

   1 /**
   2  * Copyright (C) 2012 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 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
 132 static void prefix_to_env(const char *name, const uint8_t *fqdn, size_t len)
 133 {
 134         size_t buf_len = strlen(name);
 135         struct dhcpv6_ia_prefix *p = NULL;
 136         char *buf = realloc(NULL, buf_len + 2 +
 137                         (len / sizeof(*p)) * (INET6_ADDRSTRLEN + 32));
 138         memcpy(buf, name, buf_len);
 139         buf[buf_len++] = '=';
 140
 141         uint16_t otype, olen;
 142         uint8_t *odata;
 143         dhcpv6_for_each_option(fqdn, &fqdn[len], otype, olen, odata) {
 144                 if (otype != DHCPV6_OPT_IA_PREFIX || olen + 4U < sizeof(*p))
 145                         continue;
 146
 147                 p = (struct dhcpv6_ia_prefix*)&odata[-4];
 148                 inet_ntop(AF_INET6, &p->addr, &buf[buf_len], INET6_ADDRSTRLEN);
 149                 buf_len += strlen(&buf[buf_len]);
 150                 buf_len += snprintf(&buf[buf_len], 32, "/%hhu,%u,%u ",
 151                                 p->prefix, ntohl(p->preferred),
 152                                 ntohl(p->valid));
 153         }
 154         buf[buf_len - 1] = '\0';
 155         putenv(buf);
 156 }
 157
 158
 159 void script_call(const char *status)
 160 {
 161         syslog(LOG_WARNING, "State for %s changed to %s", argv[1], status);
 162         size_t dns_len, search_len, custom_len, sntp_ip_len, sntp_dns_len;
 163         size_t sip_ip_len, sip_fqdn_len;
 164
 165         struct in6_addr *dns = odhcp6c_get_state(STATE_DNS, &dns_len);
 166         uint8_t *search = odhcp6c_get_state(STATE_SEARCH, &search_len);
 167         uint8_t *custom = odhcp6c_get_state(STATE_CUSTOM_OPTS, &custom_len);
 168         struct in6_addr *sntp = odhcp6c_get_state(STATE_SNTP_IP, &sntp_ip_len);
 169         uint8_t *sntp_dns = odhcp6c_get_state(STATE_SNTP_FQDN, &sntp_dns_len);
 170         struct in6_addr *sip = odhcp6c_get_state(STATE_SIP_IP, &sip_ip_len);
 171         uint8_t *sip_fqdn = odhcp6c_get_state(STATE_SIP_FQDN, &sip_fqdn_len);
 172
 173         size_t prefix_len;
 174         uint8_t *prefix = odhcp6c_get_state(STATE_IA_PD, &prefix_len);
 175
 176         // Don't set environment before forking, because env is leaky.
 177         if (fork() == 0) {
 178                 ipv6_to_env("RDNSS", dns, dns_len / sizeof(*dns));
 179                 ipv6_to_env("SNTP_IP", sntp, sntp_ip_len / sizeof(*sntp));
 180                 ipv6_to_env("SIP_IP", sip, sip_ip_len / sizeof(*sip));
 181                 fqdn_to_env("DOMAINS", search, search_len);
 182                 fqdn_to_env("SNTP_FQDN", sntp_dns, sntp_dns_len);
 183                 fqdn_to_env("SIP_DOMAIN", sip_fqdn, sip_fqdn_len);
 184                 bin_to_env(custom, custom_len);
 185                 prefix_to_env("PREFIXES", prefix, prefix_len);
 186
 187                 argv[2] = (char*)status;
 188                 execv(argv[0], argv);
 189                 _exit(128);
 190         }
 191
 192         // Delete lost prefixes and user opts
 193         odhcp6c_clear_state(STATE_CUSTOM_OPTS);
 194 }