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 <cipher.h>
  23 #include <glib.h>
  24 #include <glib/gprintf.h>
  25
  26 #include "uuid.h"
  27
  28 static const char *epid_ns_uuid = "fcacfb03-8a73-46ef-91b1-e5ebeeaba4fe";
  29
  30 /*
  31  * This assumes that the structure is correctly packed on all target
  32  * platforms, i.e. sizeof(uuid_t) == 16
  33  *
  34  * See also the test added to "configure". On Windows platform we know
  35  * that #pragma pack() exists and therefore can use it in the code.
  36  *
  37  */
  38 #ifdef _WIN32
  39 #pragma pack(push, 1)
  40 #endif
  41 typedef struct {
  42    guint32 time_low;
  43    guint16 time_mid;
  44    guint16 time_hi_and_version;
  45    guint8  clock_seq_hi_and_reserved;
  46    guint8  clock_seq_low;
  47    guint8  node[6];
  48 } uuid_t;
  49 #ifdef _WIN32
  50 #pragma pack(pop)
  51 #endif
  52
  53 #define UUID_OFFSET_TO_LAST_SEGMENT 24
  54
  55 static void readUUID(const char *string, uuid_t *uuid)
  56 {
  57         int i;
  58         /* Some platforms don't allow scanning to char using %02hhx */
  59         short tmp1, tmp2;
  60
  61         sscanf(string, "%08x-%04hx-%04hx-%02hx%02hx-", &uuid->time_low
  62                         , &uuid->time_mid, &uuid->time_hi_and_version
  63                         , &tmp1, &tmp2);
  64         uuid->clock_seq_hi_and_reserved = tmp1;
  65         uuid->clock_seq_low = tmp2;
  66
  67         for(i=0;i<6;i++)
  68         {
  69                 sscanf(&string[UUID_OFFSET_TO_LAST_SEGMENT+i*2], "%02hx", &tmp1);
  70                 uuid->node[i] = tmp1;
  71         }
  72 }
  73
  74 static void printUUID(uuid_t *uuid, char *string)
  75 {
  76         int i;
  77         size_t pos;
  78         sprintf(string, "%08x-%04x-%04x-%02x%02x-", uuid->time_low
  79                         , uuid->time_mid, uuid->time_hi_and_version
  80                         , uuid->clock_seq_hi_and_reserved
  81                         , uuid->clock_seq_low
  82                         );
  83         pos = strlen(string);
  84         for(i=0;i<6;i++)
  85         {
  86                 pos += sprintf(&string[pos], "%02x", uuid->node[i]);
  87         }
  88 }
  89
  90 static void createUUIDfromHash(uuid_t *uuid, const unsigned char *hash)
  91 {
  92         memcpy(uuid, hash, sizeof(uuid_t));
  93         uuid->time_hi_and_version &= GUINT16_TO_LE(0x0FFF);
  94         uuid->time_hi_and_version |= GUINT16_TO_LE(0x5000);
  95         uuid->clock_seq_hi_and_reserved &= 0x3F;
  96         uuid->clock_seq_hi_and_reserved |= 0x80;
  97 }
  98
  99 char *generateUUIDfromEPID(const gchar *epid)
 100 {
 101         uuid_t result;
 102         PurpleCipherContext *ctx;
 103         unsigned char hash[20];
 104         char buf[512];
 105
 106         readUUID(epid_ns_uuid, &result);
 107
 108         result.time_low = GUINT32_FROM_LE(result.time_low);
 109         result.time_mid = GUINT16_FROM_LE(result.time_mid);
 110         result.time_hi_and_version = GUINT16_FROM_LE(result.time_hi_and_version);
 111
 112         memcpy(buf, &result, sizeof(uuid_t));
 113         strcpy(&buf[sizeof(uuid_t)], epid);
 114
 115         ctx = purple_cipher_context_new_by_name("sha1", NULL);
 116         purple_cipher_context_append(ctx, (guchar *) buf, strlen(buf));
 117         purple_cipher_context_digest(ctx, sizeof(hash), hash, NULL);
 118         purple_cipher_context_destroy(ctx);
 119
 120         createUUIDfromHash(&result, hash);
 121
 122         result.time_low = GUINT32_TO_LE(result.time_low);
 123         result.time_mid = GUINT16_TO_LE(result.time_mid);
 124         result.time_hi_and_version = GUINT16_TO_LE(result.time_hi_and_version);
 125
 126         printUUID(&result, buf);
 127         return g_strdup(buf);
 128 }
 129
 130 /**
 131  * Generates epid from user SIP URI, hostname and IP address.
 132  * Thus epid will be the same each start and
 133  * not needed to be persistent.
 134  *
 135  * Using MAC address proved to be poorly portable solution.
 136  *
 137  * Must be g_free()'d
 138  */
 139 char *sipe_get_epid(const char *self_sip_uri,
 140                            const char *hostname,
 141                            const char *ip_address)
 142 {
 143 /* 6 last digits of hash */
 144 #define SIPE_EPID_HASH_START 14
 145 #define SIPE_EPID_HASH_END   20
 146 #define SIPE_EPID_LENGTH     (2 * (SIPE_EPID_HASH_END - SIPE_EPID_HASH_START + 1))
 147
 148         int i,j;
 149         PurpleCipherContext *ctx;
 150         unsigned char hash[SIPE_EPID_HASH_END];
 151         char out[SIPE_EPID_LENGTH + 1];
 152         char *buf = g_strdup_printf("%s:%s:%s", self_sip_uri, hostname, ip_address);
 153
 154         ctx = purple_cipher_context_new_by_name("sha1", NULL);
 155         purple_cipher_context_append(ctx, (guchar *)buf, strlen(buf));
 156         purple_cipher_context_digest(ctx, sizeof(hash), hash, NULL);
 157         purple_cipher_context_destroy(ctx);
 158
 159         for (i = SIPE_EPID_HASH_START, j = 0;
 160              i < SIPE_EPID_HASH_END;
 161              i++, j += 2) {
 162                 g_sprintf(&out[j], "%02x", hash[i]);
 163         }
 164         out[SIPE_EPID_LENGTH] = 0;
 165
 166         g_free(buf);
 167         return g_strdup(out);
 168 }
 169
 170 /*
 171   Local Variables:
 172   mode: c
 173   c-file-style: "bsd"
 174   indent-tabs-mode: t
 175   tab-width: 8
 176   End:
 177 */