Allow skipping multple remotes via management interface

The mamangement command "remote SKIP" is extended with an
optional parameter 'count' > 0. If count is greater than
number of connection entries (len), count % len is used.
On going past the index of the last connection entry,
counting is restarted from the first connection entry.

Without this, use of management-query-remote from a UI is
virtually impractical except when there are only a handful
of remote entries. Skipping the entries one by one takes
a long time when there are many entries to be skipped
(~ 1 second per entry).  Use of "remote MOD" is not an
option as change of protocol is not supported.

Management clients can determine the availability of this
feature by checking that the management interface version
is > 3. Older versions will ignore the count parameter and
behave identically to using count = 1.

Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <20210907223614.8574-1-selva.nair@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22817.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/doc/management-notes.txt b/doc/management-notes.txt
index 60d46d64d55a7072fec708a2f5e10ba81642eb05..6daa811afc08ccb09956109a93e273bca587614e 100644 (file)
--- a/doc/management-notes.txt
+++ b/doc/management-notes.txt
@@ -877,6 +877,13 @@ use this command:
 
   remote SKIP
 
+Starting OpenVPN version 2.6 (management version > 3), skip
+multiple remotes using:
+
+  remote SKIP n
+
+where n > 0 is the number of remotes to skip.
+
 COMMAND -- proxy  (OpenVPN 2.3 or higher)
 --------------------------------------------
 

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index f63422ffc55bf290060bd2f068707d942946dbb6..2e95256cd02df5bb39de8fa274c18de7dd0edf77 100644 (file)
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -389,6 +389,7 @@ management_callback_remote_cmd(void *arg, const char **p)
         {
             flags = CE_MAN_QUERY_REMOTE_SKIP;
             ret = true;
+            c->options.ce_advance_count = (p[2]) ? atoi(p[2]) : 1;
         }
         else if (!strcmp(p[1], "MOD") && p[2] && p[3])
         {
@@ -563,18 +564,28 @@ next_connection_entry(struct context *c)
                         c->c1.link_socket_addr.remote_list;
                 }
 
+                int advance_count = 1;
+
+                /* If previous connection entry was skipped by management client
+                 * with a count to advance by, apply it.
+                 */
+                if (c->options.ce_advance_count > 0)
+                {
+                    advance_count = c->options.ce_advance_count;
+                }
+
                 /*
                  * Increase the number of connection attempts
                  * If this is connect-retry-max * size(l)
                  * OpenVPN will quit
                  */
 
-                c->options.unsuccessful_attempts++;
+                c->options.unsuccessful_attempts += advance_count;
+                l->current += advance_count;
 
-                if (++l->current >= l->len)
+                if (l->current >= l->len)
                 {
-
-                    l->current = 0;
+                    l->current %= l->len;
                     if (++n_cycles >= 2)
                     {
                         msg(M_FATAL, "No usable connection profiles are present");
@@ -583,6 +594,7 @@ next_connection_entry(struct context *c)
             }
         }
 
+        c->options.ce_advance_count = 1;
         ce = l->array[l->current];
 
         if (ce->flags & CE_DISABLED)

diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index 04cc2e5c13af564e3787c6feb9acf753ec18c5ca..fec1eace5f30e544f2215e3599ade9459b46cd2f 100644 (file)
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -285,6 +285,8 @@ struct options
     bool advance_next_remote;
     /* Counts the number of unsuccessful connection attempts */
     unsigned int unsuccessful_attempts;
+    /* count of connection entries to advance by when no_advance is not set */
+    int ce_advance_count;
     /* the server can suggest a backoff time to the client, it
      * will still be capped by the max timeout between connections
      * (300s by default) */