This patch will add a simple challenge/response to people messenging you who
are not in your friends list.  Apply the patch, compile, install. 
Quit/restart your connection to bitlbee if appropriate.  Once connected, you
need to do this in &bitlbee:

  set handle_unknown challenge
  set unknown_challenge "[Antispam] to reach me, say 'rumpelstiltskin'"
  set unknown_response rumpelstiltskin
  set unknown_action add

What this will do, is send the challenge message to anyone contacting you
who's not in your friends list; but if they do say the code word
'rumpelstiltskin', they will instead be added temporarilly to your friends
list, and their message will come through.    Just like handle_unknown=add, 
if you want the add to be permanent, you'll need to do the add yourself.

This was based on bitlbee-1.2, patched April 11 2008

Author: Jason Fesler <jfesler@gigo.com>
License: Public domain.
Warrantee: None, express or implied.

I'd appreciate it if you mailed me if you found this useful.


diff -w -cr bitlbee-1.2.orig/irc.c bitlbee-1.2/irc.c
*** bitlbee-1.2.orig/irc.c	Thu Feb  7 13:25:16 2008
--- bitlbee-1.2/irc.c	Fri Apr 11 08:30:15 2008
***************
*** 113,118 ****
--- 113,121 ----
  	set_add( &irc->set, "default_target", "root", NULL, irc );
  	set_add( &irc->set, "display_namechanges", "false", set_eval_bool, irc );
  	set_add( &irc->set, "handle_unknown", "root", NULL, irc );
+  	set_add( &irc->set, "unknown_challenge", "you are not on my buddy list - message me again with SECRET-WORD to contact me", NULL, irc );
+  	set_add( &irc->set, "unknown_response", "secret-word", NULL, irc );
+  	set_add( &irc->set, "unknown_action", "add", NULL, irc );
  	set_add( &irc->set, "lcnicks", "true", set_eval_bool, irc );
  	set_add( &irc->set, "ops", "both", set_eval_ops, irc );
  	set_add( &irc->set, "password", NULL, passchange, irc );
diff -w -cr bitlbee-1.2.orig/protocols/nogaim.c bitlbee-1.2/protocols/nogaim.c
*** bitlbee-1.2.orig/protocols/nogaim.c	Sat Jan 19 16:17:52 2008
--- bitlbee-1.2/protocols/nogaim.c	Fri Apr 11 09:26:38 2008
***************
*** 636,641 ****
--- 636,671 ----
  	{
  		char *h = set_getstr( &irc->set, "handle_unknown" );
  		
+ 		/* Challenge response */
+ 		char *challenge = set_getstr( &irc->set, "unknown_challenge");
+ 		char *cresponse = set_getstr( &irc->set, "unknown_response");
+ 		char *uc_msg;
+ 		char *uc_cresponse;
+ 		char *action;
+  		if ((g_strcasecmp( h, "challenge") == 0 ) && (challenge) && (cresponse) && (msg))
+  		{
+  			uc_msg = g_ascii_strup(msg,-1);
+  			uc_cresponse = g_ascii_strup(cresponse,-1);
+  			if (g_strstr_len(uc_msg,strlen(uc_msg),uc_cresponse)) 
+  			{
+  				/* We see the required response - accept it*/
+  				action = set_getstr(&irc->set,"unknown_action");
+  				if (!action) action = "add";
+  				if (!action[0]) action="add";
+  				h=action;
+  				g_free(uc_msg);
+  				g_free(uc_cresponse);
+  			}
+  			else
+  			{
+  				ic->acc->prpl->buddy_msg(ic,handle,challenge,0); // 0 == flags ?
+  				g_free(uc_msg);
+  				g_free(uc_cresponse);
+  				return;
+  			}
+  		}
+ 		/* End of challenge/response */
+ 		
  		if( g_strcasecmp( h, "ignore" ) == 0 )
  		{
  			if( set_getbool( &irc->set, "debug" ) )