src/src/srs.c

   1 /* $Cambridge: exim/src/src/srs.c,v 1.2 2004/12/16 15:11:47 tom Exp $ */
   2
   3 /*************************************************
   4 *     Exim - an Internet mail transport agent    *
   5 *************************************************/
   6
   7 /* SRS - Sender rewriting scheme support
   8   ©2004 Miles Wilton <miles@mirtol.com>
   9   License: GPL */
  10
  11 #include "exim.h"
  12 #ifdef EXPERIMENTAL_SRS
  13
  14 #include <srs_alt.h>
  15 #include "srs.h"
  16
  17 srs_t    *srs                   = NULL;
  18 uschar   *srs_db_forward        = NULL;
  19 uschar   *srs_db_reverse        = NULL;
  20
  21
  22 /* srs_init just initialises libsrs and creates (if necessary)
  23    an srs object to use for all srs calls in this instance */
  24
  25 int eximsrs_init()
  26 {
  27   int co;
  28   uschar *list = srs_config;
  29   char secret_buf[SRS_MAX_SECRET_LENGTH];
  30   char *secret;
  31   char sbuf[4];
  32   char *sbufp;
  33   int hashlen, maxage;
  34
  35
  36   if(!srs)
  37   {
  38     // Check config
  39     if(!srs_config)
  40     {
  41       log_write(0, LOG_MAIN | LOG_PANIC,
  42           "SRS Configuration Error");
  43       return DEFER;
  44     }
  45
  46     // Get config
  47     co = 0;
  48     if((secret = string_nextinlist(&list, &co, secret_buf,
  49                                    SRS_MAX_SECRET_LENGTH)) == NULL)
  50     {
  51       log_write(0, LOG_MAIN | LOG_PANIC,
  52           "SRS Configuration Error: No secret specified");
  53       return DEFER;
  54     }
  55
  56     if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) == NULL)
  57       maxage = 31;
  58     else
  59       maxage = atoi(sbuf);
  60     if(maxage < 0 || maxage > 365)
  61     {
  62       log_write(0, LOG_MAIN | LOG_PANIC,
  63           "SRS Configuration Error: Invalid maximum timestamp age");
  64       return DEFER;
  65     }
  66
  67     if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) == NULL)
  68       hashlen = 6;
  69     else
  70       hashlen = atoi(sbuf);
  71     if(hashlen < 1 || hashlen > 20)
  72     {
  73       log_write(0, LOG_MAIN | LOG_PANIC,
  74           "SRS Configuration Error: Invalid hash length");
  75       return DEFER;
  76     }
  77
  78
  79     if((srs = srs_open(secret, strnlen(secret, SRS_MAX_SECRET_LENGTH),
  80                       maxage, hashlen, hashlen)) == NULL)
  81     {
  82       log_write(0, LOG_MAIN | LOG_PANIC,
  83           "Failed to allocate SRS memory");
  84       return DEFER;
  85     }
  86
  87
  88     if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  89       srs_set_option(srs, SRS_OPTION_USETIMESTAMP, atoi(sbuf));
  90
  91     if((sbufp = string_nextinlist(&list, &co, sbuf, sizeof(sbuf))) != NULL)
  92       srs_set_option(srs, SRS_OPTION_USEHASH, atoi(sbuf));
  93
  94     DEBUG(D_any)
  95       debug_printf("SRS initialized\n");
  96   }
  97
  98   return OK;
  99 }
 100
 101
 102 int eximsrs_done()
 103 {
 104   if(srs)
 105     srs_close(srs);
 106
 107   srs = NULL;
 108
 109   return OK;
 110 }
 111
 112
 113 int eximsrs_forward(uschar **result, uschar *orig_sender, uschar *domain)
 114 {
 115   char res[512];
 116   int n;
 117
 118   if((n = srs_forward(srs, orig_sender, domain, res, sizeof(res))) & SRS_RESULT_FAIL)
 119   {
 120     DEBUG(D_any)
 121       debug_printf("srs_forward failed (%s, %s): %s\n", orig_sender, domain, srs_geterrormsg(n));
 122     return DEFER;
 123   }
 124
 125   *result = string_copy(res);
 126   return OK;
 127 }
 128
 129
 130 int eximsrs_reverse(uschar **result, uschar *address)
 131 {
 132   char res[512];
 133   int n;
 134
 135   if((n = srs_reverse(srs, address, res, sizeof(res))) & SRS_RESULT_FAIL)
 136   {
 137     DEBUG(D_any)
 138       debug_printf("srs_reverse failed (%s): %s\n", address, srs_geterrormsg(n));
 139     if(n == SRS_RESULT_NOTSRS || n == SRS_RESULT_BADSRS)
 140       return DECLINE;
 141     if(n == SRS_RESULT_BADHASH || n == SRS_RESULT_BADTIMESTAMP || n == SRS_RESULT_TIMESTAMPEXPIRED)
 142       return FAIL;
 143     return DEFER;
 144   }
 145
 146   *result = string_copy(res);
 147   return OK;
 148 }
 149
 150
 151 int eximsrs_db_set(BOOL reverse, uschar *srs_db)
 152 {
 153   if(reverse)
 154     srs_db_reverse = string_copy(srs_db);
 155   else
 156     srs_db_forward = string_copy(srs_db);
 157
 158   if(srs_set_db_functions(srs, eximsrs_db_insert, eximsrs_db_lookup) * SRS_RESULT_FAIL)
 159     return DEFER;
 160
 161   return OK;
 162 }
 163
 164
 165 srs_result eximsrs_db_insert(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 166 {
 167   uschar *res;
 168   char buf[64];
 169
 170   srs_db_address = string_copyn(data, data_len);
 171   if(srs_generate_unique_id(srs, srs_db_address, buf, 64) & SRS_RESULT_FAIL)
 172     return DEFER;
 173
 174   srs_db_key = string_copyn(buf, 16);
 175
 176   if((res = expand_string(srs_db_forward)) == NULL)
 177     return SRS_RESULT_DBERROR;
 178
 179   if(result_len < 17)
 180     return SRS_RESULT_DBERROR;
 181
 182   strncpy(result, srs_db_key, result_len);
 183
 184   return SRS_RESULT_OK;
 185 }
 186
 187
 188 srs_result eximsrs_db_lookup(srs_t *srs, char *data, uint data_len, char *result, uint result_len)
 189 {
 190   uschar *res;
 191
 192   srs_db_key = string_copyn(data, data_len);
 193   if((res = expand_string(srs_db_reverse)) == NULL)
 194     return SRS_RESULT_DBERROR;
 195
 196   if(Ustrlen(res) >= result_len)
 197     return SRS_RESULT_ADDRESSTOOLONG;
 198
 199   strncpy(result, res, result_len);
 200
 201   return SRS_RESULT_OK;
 202 }
 203
 204
 205 #endif
 206