src/src/srs.c

   1 /* $Cambridge: exim/src/src/srs.c,v 1.8 2005/06/27 18:10:30 tom Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* SRS - Sender rewriting scheme support
   8   (C)2004 Miles Wilton <miles@mirtol.com>
   9
  10   SRS Support Version: 1.0a
  11
  12   License: GPL */
  13
  14 #include "exim.h"
  15 #ifdef EXPERIMENTAL_SRS
  16
  17 #include <srs_alt.h>
  18 #include "srs.h"
  19
  20 srs_t    *srs                   = NULL;
  21 uschar   *srs_db_forward        = NULL;
  22 uschar   *srs_db_reverse        = NULL;
  23
  24
  25 /* srs_init just initialises libsrs and creates (if necessary)
  26    an srs object to use for all srs calls in this instance */
  27
  28 int eximsrs_init()
  29 {
  30   uschar *list = srs_config;
  31   uschar secret_buf[SRS_MAX_SECRET_LENGTH];
  32   uschar *secret = NULL;
  33   uschar sbuf[4];
  34   uschar *sbufp;
  35
  36   /* Check if this instance of Exim has not initialized SRS */
  37   if(srs == NULL)
  38   {
  39     int co = 0;
  40     int hashlen, maxage;
  41     BOOL usetimestamp, usehash;
  42
  43     /* Copy config vars */
  44     hashlen = srs_hashlength;
  45     maxage = srs_maxage;
  46     usetimestamp = srs_usetimestamp;
  47     usehash = srs_usehash;
  48
  49     /* Pass srs_config var (overrides new config vars) */
  50     co = 0;
  51     if(srs_config != NULL)
  52     {
  53       secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH);
  54
  55       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  56         maxage = atoi(sbuf);
  57
  58       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  59         hashlen = atoi(sbuf);
  60
  61       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  62         usetimestamp = atoi(sbuf);
  63
  64       if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  65         usehash = atoi(sbuf);
  66     }
  67
  68     if(srs_hashmin == -1)
  69       srs_hashmin = hashlen;
  70
  71     /* First secret specified in secrets? */
  72     co = 0;
  73     list = srs_secrets;
  74     if(secret == NULL || *secret == '\0')
  75     {
  76       if((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) == NULL)
  77       {
  78         log_write(0, LOG_MAIN | LOG_PANIC,
  79             "SRS Configuration Error: No secret specified");
  80         return DEFER;
  81       }
  82     }
  83
  84     /* Check config */
  85     if(maxage < 0 || maxage > 365)
  86     {
  87       log_write(0, LOG_MAIN | LOG_PANIC,
  88           "SRS Configuration Error: Invalid maximum timestamp age");
  89       return DEFER;
  90     }
  91     if(hashlen < 1 || hashlen > 20 || srs_hashmin < 1 || srs_hashmin > 20)
  92     {
  93       log_write(0, LOG_MAIN | LOG_PANIC,
  94           "SRS Configuration Error: Invalid hash length");
  95       return DEFER;
  96     }
  97
  98     if((srs = srs_open(secret, Ustrlen(secret), maxage, hashlen, srs_hashmin)) == NULL)
  99     {
 100       log_write(0, LOG_MAIN | LOG_PANIC,
 101           "Failed to allocate SRS memory");
 102       return DEFER;
 103     }
 104
 105     srs_set_option(srs, SRS_OPTION_USETIMESTAMP, usetimestamp);
 106     srs_set_option(srs, SRS_OPTION_USEHASH, usehash);
 107
 108     /* Extra secrets? */
 109     while((secret = string_nextinlist(&list, &co, secret_buf, SRS_MAX_SECRET_LENGTH)) != NULL)
 110         srs_add_secret(srs, secret, (Ustrlen(secret) > SRS_MAX_SECRET_LENGTH) ? SRS_MAX_SECRET_LENGTH :  Ustrlen(secret));
 111
 112     DEBUG(D_any)
 113       debug_printf("SRS initialized\n");
 114   }
 115
 116   return OK;
 117 }
 118
 119
 120 int eximsrs_done()
 121 {
 122   if(srs != NULL)
 123     srs_close(srs);
 124
 125   srs = NULL;
 126
 127   return OK;
 128 }
 129
 130
 131 int eximsrs_forward(uschar **result, uschar *orig_sender, uschar *domain)
 132 {
 133   char res[512];
 134   int n;
 135
 136   if((n = srs_forward(srs, orig_sender, domain, res, sizeof(res))) & SRS_RESULT_FAIL)
 137   {
 138     DEBUG(D_any)
 139       debug_printf("srs_forward failed (%s, %s): %s\n", orig_sender, domain, srs_geterrormsg(n));
 140     return DEFER;
 141   }
 142
 143   *result = string_copy(res);
 144   return OK;
 145 }
 146
 147
 148 int eximsrs_reverse(uschar **result, uschar *address)
 149 {
 150   char res[512];
 151   int n;
 152
 153   if((n = srs_reverse(srs, address, res, sizeof(res))) & SRS_RESULT_FAIL)
 154   {
 155     DEBUG(D_any)
 156       debug_printf("srs_reverse failed (%s): %s\n", address, srs_geterrormsg(n));
 157     if(n == SRS_RESULT_NOTSRS || n == SRS_RESULT_BADSRS)
 158       return DECLINE;
 159     if(n == SRS_RESULT_BADHASH || n == SRS_RESULT_BADTIMESTAMP || n == SRS_RESULT_TIMESTAMPEXPIRED)
 160       return FAIL;
 161     return DEFER;
 162   }
 163
 164   *result = string_copy(res);
 165   return OK;
 166 }
 167
 168
 169 int eximsrs_db_set(BOOL reverse, uschar *srs_db)
 170 {
 171   if(reverse)
 172     srs_db_reverse = (srs_db == NULL ? NULL : string_copy(srs_db));
 173   else
 174     srs_db_forward = (srs_db == NULL ? NULL : string_copy(srs_db));
 175
 176   if(srs_set_db_functions(srs, (srs_db_forward ? eximsrs_db_insert : NULL),
 177                                (srs_db_reverse ? eximsrs_db_lookup : NULL)) & SRS_RESULT_FAIL)
 178     return DEFER;
 179
 180   return OK;
 181 }
 182
 183
 184 srs_result eximsrs_db_insert(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 185 {
 186   uschar *res;
 187   uschar buf[64];
 188
 189   if(srs_db_forward == NULL)
 190     return SRS_RESULT_DBERROR;
 191
 192   srs_db_address = string_copyn(data, data_len);
 193   if(srs_generate_unique_id(srs, srs_db_address, buf, 64) & SRS_RESULT_FAIL)
 194     return SRS_RESULT_DBERROR;
 195
 196   srs_db_key = string_copyn(buf, 16);
 197
 198   if((res = expand_string(srs_db_forward)) == NULL)
 199     return SRS_RESULT_DBERROR;
 200
 201   if(result_len < 17)
 202     return SRS_RESULT_DBERROR;
 203
 204   Ustrncpy(result, srs_db_key, result_len);
 205
 206   return SRS_RESULT_OK;
 207 }
 208
 209
 210 srs_result eximsrs_db_lookup(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 211 {
 212   uschar *res;
 213
 214   if(srs_db_reverse == NULL)
 215     return SRS_RESULT_DBERROR;
 216
 217   srs_db_key = string_copyn(data, data_len);
 218   if((res = expand_string(srs_db_reverse)) == NULL)
 219     return SRS_RESULT_DBERROR;
 220
 221   if(Ustrlen(res) >= result_len)
 222     return SRS_RESULT_ADDRESSTOOLONG;
 223
 224   strncpy(result, res, result_len);
 225
 226   return SRS_RESULT_OK;
 227 }
 228
 229
 230 #endif
 231