external/ibm-public/postfix/dist/src/smtpd/smtpd_dsn_fix.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      smtpd_dsn_fix 3
   6 /* SUMMARY
   7 /*      fix DSN status
   8 /* SYNOPSIS
   9 /*      #include <smtpd_dsn_fix.h>
  10 /*
  11 /*      const char *smtpd_dsn_fix(status, reply_class)
  12 /*      const char *status;
  13 /*      const char *reply_class;
  14 /* DESCRIPTION
  15 /*      smtpd_dsn_fix() transforms DSN status codes according to the
  16 /*      status information that is actually being reported. The
  17 /*      following transformations are implemented:
  18 /* .IP \(bu
  19 /*      Transform a recipient address DSN into a sender address DSN
  20 /*      when reporting sender address status information, and vice
  21 /*      versa. This transformation may be needed because some Postfix
  22 /*      access control features don't know whether the address being
  23 /*      rejected is a sender or recipient. Examples are smtpd access
  24 /*      tables, rbl reply templates, and the error mailer.
  25 /* .IP \(bu
  26 /*      Transform a sender or recipient address DSN into a non-address
  27 /*      DSN when reporting non-address status information. For
  28 /*      example, if something rejects HELO with DSN status 4.1.1
  29 /*      (unknown recipient address), then we send the more neutral
  30 /*      4.0.0 DSN instead. This transformation is needed when the
  31 /*      same smtpd access map entry or rbl reply template is used
  32 /*      for both address and non-address information.
  33 /* .PP
  34 /*      A non-address DSN is not transformed
  35 /*      when reporting sender or recipient address status information,
  36 /*      as there are many legitimate instances of such usage.
  37 /*
  38 /*      It is left up to the caller to update the initial DSN digit
  39 /*      appropriately; in Postfix this is done as late as possible,
  40 /*      because hard rejects may be changed into soft rejects for
  41 /*      all kinds of reasons.
  42 /*
  43 /*      Arguments:
  44 /* .IP status
  45 /*      A DSN status as per RFC 3463.
  46 /* .IP reply_class
  47 /*      SMTPD_NAME_SENDER, SMTPD_NAME_RECIPIENT or some other
  48 /*      null-terminated string.
  49 /* LICENSE
  50 /* .ad
  51 /* .fi
  52 /*      The Secure Mailer license must be distributed with this software.
  53 /* AUTHOR(S)
  54 /*      Wietse Venema
  55 /*      IBM T.J. Watson Research
  56 /*      P.O. Box 704
  57 /*      Yorktown Heights, NY 10598, USA
  58 /*--*/
  59 /* System library. */
  60
  61 #include <sys_defs.h>
  62 #include <ctype.h>
  63 #include <string.h>
  64
  65 /* Utility library. */
  66
  67 #include <msg.h>
  68
  69 /* Global library. */
  70
  71 /* Application-specific. */
  72
  73 #include <smtpd_dsn_fix.h>
  74
  75 struct dsn_map {
  76     const char *micro_code;             /* Final digits in mailbox D.S.N. */
  77     const char *sender_dsn;             /* Replacement sender D.S.N. */
  78     const char *rcpt_dsn;               /* Replacement recipient D.S.N. */
  79 };
  80
  81 static struct dsn_map dsn_map[] = {
  82     /* - Sender - Recipient */
  83     "1", SND_DSN, "4.1.1",              /* 4.1.1: Bad dest mbox addr */
  84     "2", "4.1.8", "4.1.2",              /* 4.1.2: Bad dest system addr */
  85     "3", "4.1.7", "4.1.3",              /* 4.1.3: Bad dest mbox addr syntax */
  86     "4", SND_DSN, "4.1.4",              /* 4.1.4: Dest mbox addr ambiguous */
  87     "5", "4.1.0", "4.1.5",              /* 4.1.5: Dest mbox addr valid */
  88     "6", SND_DSN, "4.1.6",              /* 4.1.6: Mailbox has moved */
  89     "7", "4.1.7", "4.1.3",              /* 4.1.7: Bad sender mbox addr syntax */
  90     "8", "4.1.8", "4.1.2",              /* 4.1.8: Bad sender system addr */
  91     0, "4.1.0", "4.1.0",                /* Default mapping */
  92 };
  93
  94 /* smtpd_dsn_fix - fix DSN status */
  95
  96 const char *smtpd_dsn_fix(const char *status, const char *reply_class)
  97 {
  98     struct dsn_map *dp;
  99     const char *result = status;
 100
 101     /*
 102      * Update an address-specific DSN according to what is being rejected.
 103      */
 104     if (ISDIGIT(status[0]) && strncmp(status + 1, ".1.", 3) == 0) {
 105
 106         /*
 107          * Fix recipient address DSN while rejecting a sender address. Don't
 108          * let future recipient-specific DSN codes slip past us.
 109          */
 110         if (strcmp(reply_class, SMTPD_NAME_SENDER) == 0) {
 111             for (dp = dsn_map; dp->micro_code != 0; dp++)
 112                 if (strcmp(status + 4, dp->micro_code) == 0)
 113                     break;
 114             result = dp->sender_dsn;
 115         }
 116
 117         /*
 118          * Fix sender address DSN while rejecting a recipient address. Don't
 119          * let future sender-specific DSN codes slip past us.
 120          */
 121         else if (strcmp(reply_class, SMTPD_NAME_RECIPIENT) == 0) {
 122             for (dp = dsn_map; dp->micro_code != 0; dp++)
 123                 if (strcmp(status + 4, dp->micro_code) == 0)
 124                     break;
 125             result = dp->rcpt_dsn;
 126         }
 127
 128         /*
 129          * Fix address-specific DSN while rejecting a non-address.
 130          */
 131         else {
 132             result = "4.0.0";
 133         }
 134
 135         /*
 136          * Give them a clue of what is going on.
 137          */
 138         if (strcmp(status + 2, result + 2) != 0)
 139             msg_info("mapping DSN status %s into %s status %c%s",
 140                      status, reply_class, status[0], result + 1);
 141         return (result);
 142     }
 143
 144     /*
 145      * Don't update a non-address DSN. There are many legitimate uses for
 146      * these while rejecting address or non-address information.
 147      */
 148     else {
 149         return (status);
 150     }
 151 }