--- a/src/transport.c	Tue Apr 28 23:09:28 2009 +0300
+++ b/src/transport.c	Tue Apr 28 23:10:30 2009 +0300
@@ -19,9 +19,19 @@
 
 void* transport_check (transport_t *transport, const struct transport_type *type)
 {
+    const struct transport_type *tp_type;
+
     // sanity check
-    assert(type && transport->type == type);
+    assert(type);
 
+    // look for a matching type in the transport's type list
+    for (tp_type = transport->type; tp_type; tp_type = tp_type->parent)
+        if (tp_type == type)
+            break;
+    
+    // make sure we found one
+    assert(tp_type);
+    
     // ok
     return transport;
 }
@@ -74,7 +84,7 @@
 {
     // not readable
     if (!transport->type->methods.read)
-        return -1;
+        return SET_ERROR(err, -1);
 
     // proxy off to method handler
     if (transport->type->methods.read(transport, buf, &len, err))
@@ -88,7 +98,7 @@
 {
     // XXX: not writeable
     if (!transport->type->methods.write)
-        return -1;
+        return SET_ERROR(err, -1);
 
     // proxy off to method handler
     if (transport->type->methods.write(transport, buf, &len, err))