src/core/uuid.c

   1 /**
   2  * @file uuid.c
   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 as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include <stdio.h>
  20 #include <string.h>
  21
  22 #include <glib.h>
  23 #include <glib/gprintf.h>
  24
  25 #include "cipher.h"
  26
  27 #include "uuid.h"
  28
  29 static const char *epid_ns_uuid = "fcacfb03-8a73-46ef-91b1-e5ebeeaba4fe";
  30
  31 /*
  32  * This assumes that the structure is correctly packed on all target
  33  * platforms, i.e. sizeof(uuid_t) == 16
  34  *
  35  * See also the test added to "configure". On Windows platform we know
  36  * that #pragma pack() exists and therefore can use it in the code.
  37  *
  38  */
  39 #ifdef _WIN32
  40 #pragma pack(push, 1)
  41 #endif
  42 typedef struct {
  43    guint32 time_low;
  44    guint16 time_mid;
  45    guint16 time_hi_and_version;
  46    guint8  clock_seq_hi_and_reserved;
  47    guint8  clock_seq_low;
  48    guint8  node[6];
  49 } uuid_t;
  50 #ifdef _WIN32
  51 #pragma pack(pop)
  52 #endif
  53
  54 #define UUID_OFFSET_TO_LAST_SEGMENT 24
  55
  56 static void readUUID(const char *string, uuid_t *uuid)
  57 {
  58         int i;
  59         /* Some platforms don't allow scanning to char using %02hhx */
  60         short tmp1, tmp2;
  61
  62         sscanf(string, "%08x-%04hx-%04hx-%02hx%02hx-", &uuid->time_low
  63                         , &uuid->time_mid, &uuid->time_hi_and_version
  64                         , &tmp1, &tmp2);
  65         uuid->clock_seq_hi_and_reserved = tmp1;
  66         uuid->clock_seq_low = tmp2;
  67
  68         for(i=0;i<6;i++)
  69         {
  70                 sscanf(&string[UUID_OFFSET_TO_LAST_SEGMENT+i*2], "%02hx", &tmp1);
  71                 uuid->node[i] = tmp1;
  72         }
  73 }
  74
  75 static void printUUID(uuid_t *uuid, char *string)
  76 {
  77         int i;
  78         size_t pos;
  79         sprintf(string, "%08x-%04x-%04x-%02x%02x-", uuid->time_low
  80                         , uuid->time_mid, uuid->time_hi_and_version
  81                         , uuid->clock_seq_hi_and_reserved
  82                         , uuid->clock_seq_low
  83                         );
  84         pos = strlen(string);
  85         for(i=0;i<6;i++)
  86         {
  87                 pos += sprintf(&string[pos], "%02x", uuid->node[i]);
  88         }
  89 }
  90
  91 static void createUUIDfromHash(uuid_t *uuid, const unsigned char *hash)
  92 {
  93         memcpy(uuid, hash, sizeof(uuid_t));
  94         uuid->time_hi_and_version &= GUINT16_TO_LE(0x0FFF);
  95         uuid->time_hi_and_version |= GUINT16_TO_LE(0x5000);
  96         uuid->clock_seq_hi_and_reserved &= 0x3F;
  97         uuid->clock_seq_hi_and_reserved |= 0x80;
  98 }
  99
 100 char *generateUUIDfromEPID(const gchar *epid)
 101 {
 102         uuid_t result;
 103         PurpleCipherContext *ctx;
 104         unsigned char hash[20];
 105         char buf[512];
 106
 107         readUUID(epid_ns_uuid, &result);
 108
 109         result.time_low = GUINT32_FROM_LE(result.time_low);
 110         result.time_mid = GUINT16_FROM_LE(result.time_mid);
 111         result.time_hi_and_version = GUINT16_FROM_LE(result.time_hi_and_version);
 112
 113         memcpy(buf, &result, sizeof(uuid_t));
 114         strcpy(&buf[sizeof(uuid_t)], epid);
 115
 116         ctx = purple_cipher_context_new_by_name("sha1", NULL);
 117         purple_cipher_context_append(ctx, (guchar *) buf, strlen(buf));
 118         purple_cipher_context_digest(ctx, sizeof(hash), hash, NULL);
 119         purple_cipher_context_destroy(ctx);
 120
 121         createUUIDfromHash(&result, hash);
 122
 123         result.time_low = GUINT32_TO_LE(result.time_low);
 124         result.time_mid = GUINT16_TO_LE(result.time_mid);
 125         result.time_hi_and_version = GUINT16_TO_LE(result.time_hi_and_version);
 126
 127         printUUID(&result, buf);
 128         return g_strdup(buf);
 129 }
 130
 131 /**
 132  * Generates epid from user SIP URI, hostname and IP address.
 133  * Thus epid will be the same each start and
 134  * not needed to be persistent.
 135  *
 136  * Using MAC address proved to be poorly portable solution.
 137  *
 138  * Must be g_free()'d
 139  */
 140 char *sipe_get_epid(const char *self_sip_uri,
 141                            const char *hostname,
 142                            const char *ip_address)
 143 {
 144 /* 6 last digits of hash */
 145 #define SIPE_EPID_HASH_START 14
 146 #define SIPE_EPID_HASH_END   20
 147 #define SIPE_EPID_LENGTH     (2 * (SIPE_EPID_HASH_END - SIPE_EPID_HASH_START + 1))
 148
 149         int i,j;
 150         PurpleCipherContext *ctx;
 151         unsigned char hash[SIPE_EPID_HASH_END];
 152         char out[SIPE_EPID_LENGTH + 1];
 153         char *buf = g_strdup_printf("%s:%s:%s", self_sip_uri, hostname, ip_address);
 154
 155         ctx = purple_cipher_context_new_by_name("sha1", NULL);
 156         purple_cipher_context_append(ctx, (guchar *)buf, strlen(buf));
 157         purple_cipher_context_digest(ctx, sizeof(hash), hash, NULL);
 158         purple_cipher_context_destroy(ctx);
 159
 160         for (i = SIPE_EPID_HASH_START, j = 0;
 161              i < SIPE_EPID_HASH_END;
 162              i++, j += 2) {
 163                 g_sprintf(&out[j], "%02x", hash[i]);
 164         }
 165         out[SIPE_EPID_LENGTH] = 0;
 166
 167         g_free(buf);
 168         return g_strdup(out);
 169 }
 170
 171 /*
 172   Local Variables:
 173   mode: c
 174   c-file-style: "bsd"
 175   indent-tabs-mode: t
 176   tab-width: 8
 177   End:
 178 */