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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      smtpd_resolve 3
   6 /* SUMMARY
   7 /*      caching resolve client
   8 /* SYNOPSIS
   9 /*      #include <smtpd_resolve.h>
  10 /*
  11 /*      void    smtpd_resolve_init(cache_size)
  12 /*      int     cache_size;
  13 /*
  14 /*      const RESOLVE_REPLY *smtpd_resolve_addr(addr)
  15 /*      const char *addr;
  16 /* DESCRIPTION
  17 /*      This module maintains a resolve client cache that persists
  18 /*      across SMTP sessions (not process life times). Addresses
  19 /*      are always resolved in local rewriting context.
  20 /*
  21 /*      smtpd_resolve_init() initializes the cache and must
  22 /*      called once before the cache can be used.
  23 /*
  24 /*      smtpd_resolve_addr() resolves one address or returns
  25 /*      a known result from cache.
  26 /*
  27 /*      Arguments:
  28 /* .IP cache_size
  29 /*      The requested cache size.
  30 /* .IP addr
  31 /*      The address to resolve.
  32 /* DIAGNOSTICS
  33 /*      All errors are fatal.
  34 /* BUGS
  35 /*      The recipient address is always case folded to lowercase.
  36 /*      Changing this requires great care, since the address is used
  37 /*      for policy lookups.
  38 /* LICENSE
  39 /* .ad
  40 /* .fi
  41 /*      The Secure Mailer license must be distributed with this software.
  42 /* AUTHOR(S)
  43 /*      Wietse Venema
  44 /*      IBM T.J. Watson Research
  45 /*      P.O. Box 704
  46 /*      Yorktown Heights, NY 10598, USA
  47 /*--*/
  48
  49 /* System library. */
  50
  51 #include <sys_defs.h>
  52
  53 /* Utility library. */
  54
  55 #include <msg.h>
  56 #include <mymalloc.h>
  57 #include <vstring.h>
  58 #include <ctable.h>
  59 #include <stringops.h>
  60
  61 /* Global library. */
  62
  63 #include <rewrite_clnt.h>
  64 #include <resolve_clnt.h>
  65 #include <mail_proto.h>
  66
  67 /* Application-specific. */
  68
  69 #include <smtpd_resolve.h>
  70
  71 static CTABLE *smtpd_resolve_cache;
  72
  73 #define STR(x) vstring_str(x)
  74
  75 /* resolve_pagein - page in an address resolver result */
  76
  77 static void *resolve_pagein(const char *addr, void *unused_context)
  78 {
  79     static VSTRING *query;
  80     RESOLVE_REPLY *reply;
  81
  82     /*
  83      * Initialize on the fly.
  84      */
  85     if (query == 0)
  86         query = vstring_alloc(10);
  87
  88     /*
  89      * Initialize.
  90      */
  91     reply = (RESOLVE_REPLY *) mymalloc(sizeof(*reply));
  92     resolve_clnt_init(reply);
  93
  94     /*
  95      * Resolve the address.
  96      */
  97     rewrite_clnt_internal(MAIL_ATTR_RWR_LOCAL, addr, query);
  98     resolve_clnt_query(STR(query), reply);
  99     lowercase(STR(reply->recipient));           /* XXX */
 100
 101     /*
 102      * Save the result.
 103      */
 104     return ((void *) reply);
 105 }
 106
 107 /* resolve_pageout - page out an address resolver result */
 108
 109 static void resolve_pageout(void *data, void *unused_context)
 110 {
 111     RESOLVE_REPLY *reply = (RESOLVE_REPLY *) data;
 112
 113     resolve_clnt_free(reply);
 114     myfree((void *) reply);
 115 }
 116
 117 /* smtpd_resolve_init - set up global cache */
 118
 119 void    smtpd_resolve_init(int cache_size)
 120 {
 121
 122     /*
 123      * Sanity check.
 124      */
 125     if (smtpd_resolve_cache)
 126         msg_panic("smtpd_resolve_init: multiple initialization");
 127
 128     /*
 129      * Initialize the resolved address cache. Note: the cache persists across
 130      * SMTP sessions so we cannot make it dependent on session state.
 131      */
 132     smtpd_resolve_cache = ctable_create(cache_size, resolve_pagein,
 133                                         resolve_pageout, (void *) 0);
 134 }
 135
 136 /* smtpd_resolve_addr - resolve cached addres */
 137
 138 const RESOLVE_REPLY *smtpd_resolve_addr(const char *addr)
 139 {
 140
 141     /*
 142      * Sanity check.
 143      */
 144     if (smtpd_resolve_cache == 0)
 145         msg_panic("smtpd_resolve_addr: missing initialization");
 146
 147     /*
 148      * Reply from the read-through cache.
 149      */
 150     return (const RESOLVE_REPLY *) ctable_locate(smtpd_resolve_cache, addr);
 151 }