New expansion operator: reverse_ip

6 files changed, 58 insertions, 9 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 98048c6bc..003ae6db8 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -1,4 +1,4 @@
-. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.78 2010/06/05 21:42:53 pdp Exp $
+. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.79 2010/06/05 23:50:18 pdp Exp $
 .
 . /////////////////////////////////////////////////////////////////////////////
 . This is the primary source of the Exim Manual. It is an xfpt document that is
@@ -9615,6 +9615,21 @@ srandomdev() or srandom(), or a custom implementation even weaker than
 random().
 
 
+.vitem &*${reverse_ip:*&<&'ipaddr'&>&*}*&
+.cindex "expansion" "IP address"
+This operator reverses an IP address; for IPv4 addresses, the result is in
+dotted-quad decimal form, while for IPv6 addreses the result is in
+dotted-nibble hexadecimal form.  In both cases, this is the "natural" form
+for DNS.  For example,
+.code
+${reverse_ip:192.0.2.4} and ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
+.endd
+returns
+.code
+4.2.0.192 and 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
+.endd
+
+
 .vitem &*${rfc2047:*&<&'string'&>&*}*&
 .cindex "expansion" "RFC 2047"
 .cindex "RFC 2047" "expansion operator"
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 421997b01..0591e4115 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.621 2010/06/05 11:13:29 pdp Exp $
+$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.622 2010/06/05 23:50:18 pdp Exp $
 
 Change log file for Exim from version 4.21
 -------------------------------------------
@@ -31,6 +31,8 @@ PP/08 Bugzilla 926: switch ClamAV to use the new zINSTREAM API for content
       filtering; old API available if built with WITH_OLD_CLAMAV_STREAM=yes
       NB: ClamAV planning to remove STREAM in "middle of 2010".
 
+PP/09 Implemented reverse_ip expansion operator.
+
 
 Exim version 4.72
 -----------------
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index c4d38fd4f..35ed9a399 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.168 2010/06/05 11:13:29 pdp Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.169 2010/06/05 23:50:18 pdp Exp $
 
 New Features in Exim
 --------------------
@@ -43,6 +43,14 @@ Version 4.73
     malware-scanning framework.  This is intended purely as a debugging aid
     to ensure that Exim's scanning is working, not to replace other tools.
 
+ 5. There is a new expansion operator, "reverse_ip", which will reverse IP
+    addresses; IPv4 into dotted quad, IPv6 into dotted nibble.  Examples:
+
+      ${reverse_ip:192.0.2.4}
+       -> 4.2.0.192
+      ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
+       -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
+
 
 Version 4.72
 ------------
diff --git a/src/src/expand.c b/src/src/expand.c
index 6e47125bb..e5daff1a8 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/expand.c,v 1.105 2009/11/16 19:50:36 nm4 Exp $ */
+/* $Cambridge: exim/src/src/expand.c,v 1.106 2010/06/05 23:50:18 pdp Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -156,6 +156,7 @@ static uschar *op_table_underscore[] = {
   US"from_utf8",
   US"local_part",
   US"quote_local_part",
+  US"reverse_ip",
   US"time_eval",
   US"time_interval"};
 
@@ -163,6 +164,7 @@ enum {
   EOP_FROM_UTF8,
   EOP_LOCAL_PART,
   EOP_QUOTE_LOCAL_PART,
+  EOP_REVERSE_IP,
   EOP_TIME_EVAL,
   EOP_TIME_INTERVAL };
 
@@ -5790,6 +5792,25 @@ while (*s != 0)
         continue;
         }
 
+      /* Reverse IP, including IPv6 to dotted-nibble */
+
+      case EOP_REVERSE_IP:
+        {
+        int family, maskptr;
+        uschar reversed[128];
+
+        family = string_is_ip_address(sub, &maskptr);
+        if (family == 0)
+          {
+          expand_string_message = string_sprintf(
+              "reverse_ip() not given an IP address [%s]", sub);
+          goto EXPAND_FAILED;
+          }
+        invert_address(reversed, sub);
+        yield = string_cat(yield, &size, &ptr, reversed, Ustrlen(reversed));
+        continue;
+        }
+
       /* Unknown operator */
 
       default:
diff --git a/src/src/functions.h b/src/src/functions.h
index 436038735..00f8bb7ba 100644
--- a/src/src/functions.h
+++ b/src/src/functions.h
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/functions.h,v 1.49 2010/06/05 11:13:30 pdp Exp $ */
+/* $Cambridge: exim/src/src/functions.h,v 1.50 2010/06/05 23:50:18 pdp Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -141,6 +141,7 @@ extern int     host_nmtoa(int, int *, int, uschar *, int);
 extern uschar *host_ntoa(int, const void *, uschar *, int *);
 extern int     host_scan_for_local_hosts(host_item *, host_item **, BOOL *);
 
+extern void    invert_address(uschar *, uschar *);
 extern int     ip_bind(int, int, uschar *, int);
 extern int     ip_connect(int, int, uschar *, int, int);
 extern void    ip_keepalive(int, uschar *, BOOL);
diff --git a/src/src/verify.c b/src/src/verify.c
index cc821a201..371883a37 100644
--- a/src/src/verify.c
+++ b/src/src/verify.c
@@ -1,4 +1,4 @@
-/* $Cambridge: exim/src/src/verify.c,v 1.54 2009/11/16 19:50:37 nm4 Exp $ */
+/* $Cambridge: exim/src/src/verify.c,v 1.55 2010/06/05 23:50:18 pdp Exp $ */
 
 /*************************************************
 *     Exim - an Internet mail transport agent    *
@@ -2513,16 +2513,18 @@ return verify_check_this_host(listptr, sender_host_cache, NULL,
 
 
 /*************************************************
-*    Invert an IP address for a DNS black list   *
+*              Invert an IP address              *
 *************************************************/
 
-/*
+/* Originally just used for DNS xBL lists, now also used for the
+reverse_ip expansion operator.
+
 Arguments:
   buffer         where to put the answer
   address        the address to invert
 */
 
-static void
+void
 invert_address(uschar *buffer, uschar *address)
 {
 int bin[4];