- Patch for stub-no-cache and forward-no-cache options that disable

caching for the contents of that stub or forward, for when you
  want immediate changes visible, from Bjoern A. Zeeb.


git-svn-id: file:///svn/unbound/trunk@4846 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -2,6 +2,9 @@
 	- unbound-checkconf checks if modules exist and prints if they are
 	  not compiled in the name of the wrong module.
 	- document --enable-subnet in doc/README.
+	- Patch for stub-no-cache and forward-no-cache options that disable
+	  caching for the contents of that stub or forward, for when you
+	  want immediate changes visible, from Bjoern A. Zeeb.
 
 7 August 2018: Ralph
 	- Make capsforid fallback QNAME minimisation aware.

iterator/iter_delegpt.h

@@ -85,6 +85,8 @@ struct delegpt {
 	uint8_t ssl_upstream;
 	/** delegpt from authoritative zone that is locally hosted */
 	uint8_t auth_dp;
+	/*** no cache */
+	int no_cache;
 };
 
 /**

iterator/iter_fwd.c

@@ -272,6 +272,8 @@ read_forwards(struct iter_forwards* fwd, struct config_file* cfg)
 		 * last resort will ask for parent-side NS record and thus
 		 * fallback to the internet name servers on a failure */
 		dp->has_parent_side_NS = (uint8_t)!s->isfirst;
+		/* Do not cache if set. */
+		dp->no_cache = s->no_cache;
 		/* use SSL for queries to this forwarder */
 		dp->ssl_upstream = (uint8_t)s->ssl_upstream;
 		verbose(VERB_QUERY, "Forward zone server list:");

iterator/iter_hints.c

@@ -283,6 +283,8 @@ read_stubs(struct iter_hints* hints, struct config_file* cfg)
 		 * last resort will ask for parent-side NS record and thus
 		 * fallback to the internet name servers on a failure */
 		dp->has_parent_side_NS = (uint8_t)!s->isfirst;
+		/* Do not cache if set. */
+		dp->no_cache = s->no_cache;
 		/* ssl_upstream */
 		dp->ssl_upstream = (uint8_t)s->ssl_upstream;
 		delegpt_log(VERB_QUERY, dp);

iterator/iterator.c

@@ -1126,6 +1126,36 @@ forward_request(struct module_qstate* qstate, struct iter_qstate* iq)
 	return 1;
 }
 
+static int
+iter_stub_fwd_no_cache(struct module_qstate *qstate, struct iter_qstate *iq)
+{
+	struct iter_hints_stub *stub;
+	struct delegpt *dp;
+
+	/* Check for stub. */
+	stub = hints_lookup_stub(qstate->env->hints, iq->qchase.qname,
+	    iq->qchase.qclass, iq->dp);
+	if (stub != NULL && stub->dp != NULL) {
+		verbose(VERB_ALGO, "%s: stub for '%s'/'%s' no_cache %d", __func__,
+		    iq->qchase.qname, stub->dp->name, stub->dp->no_cache);
+		return (stub->dp->no_cache);
+	}
+
+	/* Check for forward. */
+	dp = forwards_lookup(qstate->env->fwds, iq->qchase.qname, iq->qchase.qclass);
+	if (dp) {
+		verbose(VERB_ALGO, "%s: fwd for '%s'/'%s' no_cache %d", __func__,
+		    iq->qchase.qname, dp->name, dp->no_cache);
+		return (dp->no_cache);
+	}
+
+#if 0
+	verbose(VERB_ALGO, "%s: no stub or fwd for '%s' found no_cache 0",
+	    __func__, iq->qchase.qname);
+#endif
+	return (0);
+}
+
 /** 
  * Process the initial part of the request handling. This state roughly
  * corresponds to resolver algorithms steps 1 (find answer in cache) and 2
@@ -1197,7 +1227,13 @@ processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
 	/* This either results in a query restart (CNAME cache response), a
 	 * terminating response (ANSWER), or a cache miss (null). */
 	
-	if(qstate->blacklist) {
+	if (iter_stub_fwd_no_cache(qstate, iq)) {
+		/* Asked to not query cache. */
+		verbose(VERB_ALGO, "no-cache set, going to the network");
+		qstate->no_cache_lookup = 1;
+		qstate->no_cache_store = 1;
+		msg = NULL;
+	} else if(qstate->blacklist) {
 		/* if cache, or anything else, was blacklisted then
 		 * getting older results from cache is a bad idea, no cache */
 		verbose(VERB_ALGO, "cache blacklisted, going to the network");

util/config_file.h

@@ -572,6 +572,8 @@ struct config_stub {
 	int isfirst;
 	/** use SSL for queries to this stub */
 	int ssl_upstream;
+	/*** no cache */
+	int no_cache;
 };
 
 /**

util/configlexer.lex

@@ -302,12 +302,14 @@ stub-addr{COLON}		{ YDVAR(1, VAR_STUB_ADDR) }
 stub-host{COLON}		{ YDVAR(1, VAR_STUB_HOST) }
 stub-prime{COLON}		{ YDVAR(1, VAR_STUB_PRIME) }
 stub-first{COLON}		{ YDVAR(1, VAR_STUB_FIRST) }
+stub-no-cache{COLON}		{ YDVAR(1, VAR_STUB_NO_CACHE) }
 stub-ssl-upstream{COLON}	{ YDVAR(1, VAR_STUB_SSL_UPSTREAM) }
 stub-tls-upstream{COLON}	{ YDVAR(1, VAR_STUB_SSL_UPSTREAM) }
 forward-zone{COLON}		{ YDVAR(0, VAR_FORWARD_ZONE) }
 forward-addr{COLON}		{ YDVAR(1, VAR_FORWARD_ADDR) }
 forward-host{COLON}		{ YDVAR(1, VAR_FORWARD_HOST) }
 forward-first{COLON}		{ YDVAR(1, VAR_FORWARD_FIRST) }
+forward-no-cache{COLON}		{ YDVAR(1, VAR_FORWARD_NO_CACHE) }
 forward-ssl-upstream{COLON}	{ YDVAR(1, VAR_FORWARD_SSL_UPSTREAM) }
 forward-tls-upstream{COLON}	{ YDVAR(1, VAR_FORWARD_SSL_UPSTREAM) }
 auth-zone{COLON}		{ YDVAR(0, VAR_AUTH_ZONE) }

util/configparser.h

@@ -289,7 +289,9 @@ extern int yydebug;
     VAR_LOW_RTT_PERMIL = 499,
     VAR_ALLOW_NOTIFY = 500,
     VAR_TLS_WIN_CERT = 501,
-    VAR_TCP_CONNECTION_LIMIT = 502
+    VAR_TCP_CONNECTION_LIMIT = 502,
+    VAR_FORWARD_NO_CACHE = 503,
+    VAR_STUB_NO_CACHE = 504
   };
 #endif
 /* Tokens.  */
@@ -538,6 +540,8 @@ extern int yydebug;
 #define VAR_ALLOW_NOTIFY 500
 #define VAR_TLS_WIN_CERT 501
 #define VAR_TCP_CONNECTION_LIMIT 502
+#define VAR_FORWARD_NO_CACHE 503
+#define VAR_STUB_NO_CACHE 504
 
 /* Value type.  */
 #if ! defined YYSTYPE && ! defined YYSTYPE_IS_DECLARED
@@ -548,7 +552,7 @@ union YYSTYPE
 
 	char*	str;
 
-#line 552 "util/configparser.h" /* yacc.c:1909  */
+#line 556 "util/configparser.h" /* yacc.c:1909  */
 };
 
 typedef union YYSTYPE YYSTYPE;

util/configparser.y

@@ -159,6 +159,7 @@ extern struct config_parser_state* cfg_parser;
 %token VAR_AUTH_ZONE VAR_ZONEFILE VAR_MASTER VAR_URL VAR_FOR_DOWNSTREAM
 %token VAR_FALLBACK_ENABLED VAR_TLS_ADDITIONAL_PORT VAR_LOW_RTT VAR_LOW_RTT_PERMIL
 %token VAR_ALLOW_NOTIFY VAR_TLS_WIN_CERT VAR_TCP_CONNECTION_LIMIT
+%token VAR_FORWARD_NO_CACHE VAR_STUB_NO_CACHE
 
 %%
 toplevelvars: /* empty */ | toplevelvars toplevelvar ;
@@ -269,7 +270,7 @@ stubstart: VAR_STUB_ZONE
 contents_stub: contents_stub content_stub 
 	| ;
 content_stub: stub_name | stub_host | stub_addr | stub_prime | stub_first |
-	stub_ssl_upstream
+	stub_no_cache | stub_ssl_upstream
 	;
 forwardstart: VAR_FORWARD_ZONE
 	{
@@ -286,7 +287,7 @@ forwardstart: VAR_FORWARD_ZONE
 contents_forward: contents_forward content_forward 
 	| ;
 content_forward: forward_name | forward_host | forward_addr | forward_first |
-	forward_ssl_upstream
+	forward_no_cache | forward_ssl_upstream
 	;
 viewstart: VAR_VIEW
 	{
@@ -2077,6 +2078,15 @@ stub_first: VAR_STUB_FIRST STRING_ARG
 		free($2);
 	}
 	;
+stub_no_cache: VAR_STUB_NO_CACHE STRING_ARG
+	{
+		OUTYY(("P(stub-no-cache:%s)\n", $2));
+		if(strcmp($2, "yes") != 0 && strcmp($2, "no") != 0)
+			yyerror("expected yes or no.");
+		else cfg_parser->cfg->stubs->no_cache=(strcmp($2, "yes")==0);
+		free($2);
+	}
+	;
 stub_ssl_upstream: VAR_STUB_SSL_UPSTREAM STRING_ARG
 	{
 		OUTYY(("P(stub-ssl-upstream:%s)\n", $2));
@@ -2130,6 +2140,15 @@ forward_first: VAR_FORWARD_FIRST STRING_ARG
 		free($2);
 	}
 	;
+forward_no_cache: VAR_FORWARD_NO_CACHE STRING_ARG
+	{
+		OUTYY(("P(forward-no-cache:%s)\n", $2));
+		if(strcmp($2, "yes") != 0 && strcmp($2, "no") != 0)
+			yyerror("expected yes or no.");
+		else cfg_parser->cfg->forwards->no_cache=(strcmp($2, "yes")==0);
+		free($2);
+	}
+	;
 forward_ssl_upstream: VAR_FORWARD_SSL_UPSTREAM STRING_ARG
 	{
 		OUTYY(("P(forward-ssl-upstream:%s)\n", $2));