File contents

Index: src/query.c
===================================================================
--- src/query.c	(revision 14)
+++ src/query.c	(working copy)
@@ -63,6 +63,10 @@
 
   qu->cname_dgram= 0;
   qu->cname_dglen= qu->cname_begin= 0;
+  /* Patch to allow CNAME chains */
+  /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+  /* Allow CNAME chains up to some sane limit */
+  qu->cname_alias_hops_left = 10;
 
   adns__vbuf_init(&qu->search_vb);
   qu->search_origlen= qu->search_pos= qu->search_doneabs= 0;
Index: src/internal.h
===================================================================
--- src/internal.h	(revision 14)
+++ src/internal.h	(working copy)
@@ -231,6 +231,11 @@
   int cname_dglen, cname_begin;
   /* If non-0, has been allocated using . */
 
+  /* Patch to allow CNAME chains */
+  /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+  int cname_alias_hops_left;
+  /* The number of cname alias hops we will allow */
+
   vbuf search_vb;
   int search_origlen, search_pos, search_doneabs;
   /* Used by the searching algorithm.  The query domain in textual form
Index: src/reply.c
===================================================================
--- src/reply.c	(revision 14)
+++ src/reply.c	(working copy)
@@ -190,12 +190,17 @@
       if (qu->flags & adns_qf_cname_forbid) {
 	adns__query_fail(qu,adns_s_prohibitedcname);
 	return;
-      } else if (qu->cname_dgram) { /* Ignore second and subsequent CNAME(s) */
+      }
+
+    /* Patch to allow CNAME chains */
+    /* Credits: Brad Spencer, see http://www.chiark.greenend.org.uk/pipermail/adns-discuss/2006/001161.html */
+    else if (qu->cname_dgram && --(qu->cname_alias_hops_left) <= 0) { /* Don't follow "too long" CNAME chains */
 	adns__debug(ads,serv,qu,"allegedly canonical name %s"
-		    " is actually alias for %s", qu->answer->cname,
+           " is actually alias for %s and aliases too deep",
+                    qu->answer->cname,
 		    adns__diag_domain(ads,serv,qu, &qu->vb,
 				      dgram,dglen,rdstart));
-	adns__query_fail(qu,adns_s_prohibitedcname);
+    adns__query_fail(qu,adns_s_norecurse);
 	return;
       } else if (wantedrrs) { /* Ignore CNAME(s) after RR(s). */
 	adns__debug(ads,serv,qu,"ignoring CNAME (to %s) coexisting with RR",