[exim-dev] DCC fixes/improvements

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Autor: Wolfgang Breyha
Data:  
Dla: exim-dev
Temat: [exim-dev] DCC fixes/improvements
Hi!

I did some improvements and fixes to my DCC code. Diff is against current git.

improvements:
*) reason: GMX decided to redesign their mailsystem in a very bad way. temp
rejected mails are resent by several different IPs now. Very nice for
greylisting. Even with selective greylisting troubles are very likely since
they are listed on RBLs, too.
changes: by defining $acl_m_dcc_override_client_ip it is possible to set the
ip used for greylisting instead of using sender_host_address

I use it with an ACL like
>   warn    set acl_m_dcc_override_client_ip = ${lookup{$sender_helo_name}lsearch{/etc/mail/multipleip_sites}{$value}{}}
>           condition = ${if def:acl_m_dcc_override_client_ip}
>           log_message = dbg: acl_m_dcc_override_client_ip set to $acl_m_dcc_override_client_ip

and
# cat /etc/mail/multipleip_sites
mout-xforward.gmx.net        82.165.159.12
mout.gmx.net            212.227.15.16


Most likely this is useful for other sites, too.

changes/fixes:
*) I completely removed dcc_daemon_ip and dcc_ip_option. Both were leftovers
from the local_scan() code. They made no sense at all. dcc_daemon_ip rendered
dccifd_address useless if used to set a tcp socket address and port.
*) instead of copying the fixed value "header" as options, dccifd_options is
used as intended.

Please commit the changes to git if there are no complaints.

Greetings, Wolfgang
--
Wolfgang Breyha <wbreyha@???> | http://www.blafasel.at/
Vienna University Computer Center | Austria

diff --git a/src/src/dcc.c b/src/src/dcc.c
index 680eea5..44c0c00 100644
--- a/src/src/dcc.c
+++ b/src/src/dcc.c
@@ -2,7 +2,7 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/


-/* Copyright (c) Wolfgang Breyha 2005-2012
+/* Copyright (c) Wolfgang Breyha 2005-2013
  * Vienna University Computer Center
  * wbreyha@???
  * See the file NOTICE for conditions of use and distribution.
@@ -36,7 +36,8 @@ int flushbuffer (int socket, uschar *buffer)
     DEBUG(D_acl)
       debug_printf("DCC: Error writing buffer to socket: %s\n", strerror(errno));
     retval = errno;
-  } else {
+  }
+  else {
     DEBUG(D_acl)
       debug_printf("DCC: Wrote buffer to socket:\n%s\n", buffer);
     retval = 0;
@@ -48,12 +49,11 @@ int dcc_process(uschar **listptr) {
   int sep = 0;
   uschar *list = *listptr;
   FILE *data_file;
-  uschar *dcc_daemon_ip = US"";
   uschar *dcc_default_ip_option = US"127.0.0.1";
-  uschar *dcc_ip_option = US"";
   uschar *dcc_helo_option = US"localhost";
   uschar *dcc_reject_message = US"Rejected by DCC";
   uschar *xtra_hdrs = NULL;
+  uschar *override_client_ip  = NULL;


   /* from local_scan */
   int i, j, k, c, retval, sockfd, resp, line;
@@ -140,24 +140,26 @@ int dcc_process(uschar **listptr) {
   /* opts is what we send as dccifd options - see man dccifd */
   /* We don't support any other option than 'header' so just copy that */
   bzero(opts,sizeof(opts));
-  Ustrncpy(opts, "header", sizeof(opts)-1);
-  Ustrncpy(client_ip, dcc_ip_option, sizeof(client_ip)-1);
-  /* If the dcc_client_ip is not provided use the
-   * sender_host_address or 127.0.0.1 if it is NULL */
-  DEBUG(D_acl)
-    debug_printf("DCC: my_ip_option = %s - client_ip = %s - sender_host_address = %s\n", dcc_ip_option, client_ip, sender_host_address);
-  if(!(Ustrcmp(client_ip, ""))){
-    /* Do we have a sender_host_address or is it NULL? */
-    if(sender_host_address){
-      Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
-    } else {
-      /* sender_host_address is NULL which means it comes from localhost */
-      Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
-    }
+  Ustrncpy(opts, dccifd_options, sizeof(opts)-1);
+  /* if $acl_m_dcc_override_client_ip is set use it */
+  if (((override_client_ip = expand_string(US"$acl_m_dcc_override_client_ip")) != NULL) && 
+       (override_client_ip[0] != '\0')) {
+    Ustrncpy(client_ip, override_client_ip, sizeof(client_ip)-1);
+    DEBUG(D_acl)
+      debug_printf("DCC: Client IP (overridden): %s\n", client_ip);
+  } 
+  else if(sender_host_address) {
+  /* else if $sender_host_address is available use that? */
+    Ustrncpy(client_ip, sender_host_address, sizeof(client_ip)-1);
+    DEBUG(D_acl)
+      debug_printf("DCC: Client IP (sender_host_address): %s\n", client_ip);
+  } 
+  else {
+    /* sender_host_address is NULL which means it comes from localhost */
+    Ustrncpy(client_ip, dcc_default_ip_option, sizeof(client_ip)-1);
+    DEBUG(D_acl)
+      debug_printf("DCC: Client IP (default): %s\n", client_ip);
   }
-  DEBUG(D_acl)
-    debug_printf("DCC: Client IP: %s\n", client_ip);
-  Ustrncpy(sockip, dcc_daemon_ip, sizeof(sockip)-1);
   /* strncat(opts, my_request, strlen(my_request)); */
   Ustrcat(opts, "\n");
   Ustrncat(opts, client_ip, sizeof(opts)-Ustrlen(opts)-1);
@@ -186,7 +188,7 @@ int dcc_process(uschar **listptr) {
    * Now creating the socket connection *
    **************************************/


-  /* If there is a dcc_daemon_ip, we use a tcp socket, otherwise a UNIX socket */
+  /* If sockip contains an ip, we use a tcp socket, otherwise a UNIX socket */
   if(Ustrcmp(sockip, "")){
     ipaddress = gethostbyname((char *)sockip);
     bzero((char *) &serv_addr_in, sizeof(serv_addr_in));