- Versions 3.0.x syntax with multiple name->code option definitions is now

supported.  Note that, similarly to 3.0.x, for by-code lookups only the
  last option definition is used.  [ISC-Bugs #17613]

RELNOTES

@@ -200,6 +200,10 @@ work on other platforms. Please report any problems and suggested fixes to
   one of either of those).  This resolves a bug where dual stack clients
   would not be able to regain their names after either expiration event.
 
+- Versions 3.0.x syntax with multiple name->code option definitions is now
+  supported.  Note that, similarly to 3.0.x, for by-code lookups only the
+  last option definition is used.
+
 			Changes since 4.1.0a1
 
 - Corrected list of failover state values in dhcpd man page.

client/clparse.c

@@ -502,6 +502,7 @@ void parse_client_statement (cfile, ip, config)
 			return;
 		}
 
+		known = 0;
 		status = parse_option_name(cfile, 1, &known, &option);
 		if (status != ISC_R_SUCCESS || option == NULL)
 			return;
@@ -521,6 +522,18 @@ void parse_client_statement (cfile, ip, config)
 			option_dereference(&option, MDL);
 			return;
 		}
+
+		/*
+		 * If the option was known, remove it from the code and name
+		 * hash tables before redefining it.
+		 */
+		if (known) {
+			option_name_hash_delete(option->universe->name_hash,
+						option->name, 0, MDL);
+			option_code_hash_delete(option->universe->code_hash,
+						&option->code, 0, MDL);
+		}
+
 		parse_option_code_definition(cfile, option);
 		option_dereference(&option, MDL);
 		return;

common/parse.c

@@ -1757,9 +1757,18 @@ int parse_option_code_definition (cfile, option)
 	oldopt = NULL;
 	option_code_hash_lookup(&oldopt, option->universe->code_hash,
 				&option->code, 0, MDL);
-	if (oldopt) {
+	if (oldopt != NULL) {
+		/*
+		 * XXX: This illegalizes a configuration syntax that was
+		 * valid in 3.0.x, where multiple name->code mappings are
+		 * given, but only one code->name mapping survives.  It is
+		 * unclear what can or should be done at this point, but it
+		 * seems best to retain 3.0.x behaviour for upgrades to go
+		 * smoothly.
+		 *
 		option_name_hash_delete(option->universe->name_hash,
 					oldopt->name, 0, MDL);
+		 */
 		option_code_hash_delete(option->universe->code_hash,
 					&oldopt->code, 0, MDL);
 

server/confpars.c

@@ -724,6 +724,20 @@ int parse_statement (cfile, group, type, host_decl, declaration)
 					break;
 				}
 				next_token (&val, (unsigned *)0, cfile);
+
+				/*
+				 * If the option was known, remove it from the
+				 * code and name hashes before redefining it.
+				 */
+				if (known) {
+					option_name_hash_delete(
+						option->universe->name_hash,
+							option->name, 0, MDL);
+					option_code_hash_delete(
+						option->universe->code_hash,
+							&option->code, 0, MDL);
+				}
+
 				parse_option_code_definition(cfile, option);
 				option_dereference(&option, MDL);
 				return declaration;