Patch for: http://trac.lighttpd.net/trac/ticket/1545

Allows the headers to be used by mod_extforward to be specified in config.
For example for use with a Zeus ZXTM loadbalancer: 

extforward.headers = ("X-Cluster-Client-Ip") 


diff -Nur ../lighttpd-1.4.18-original/src/mod_extforward.c ./src/mod_extforward.c
--- ../lighttpd-1.4.18-original/src/mod_extforward.c	2007-08-18 11:43:35.000000000 +0200
+++ ./src/mod_extforward.c	2007-12-21 15:09:35.000000000 +0100
@@ -75,6 +75,7 @@
 
 typedef struct {
 	array *forwarder;
+	array *headers;
 } plugin_config;
 
 typedef struct {
@@ -130,6 +131,7 @@
 			if (!s) continue;
 
 			array_free(s->forwarder);
+			array_free(s->headers);
 
 			free(s);
 		}
@@ -149,7 +151,8 @@
 	size_t i = 0;
 
 	config_values_t cv[] = {
-		{ "extforward.forwarder",             NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION },       /* 0 */
+		{ "extforward.forwarder",       NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION },       /* 0 */
+		{ "extforward.headers",         NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION },       /* 1 */
 		{ NULL,                         NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
 	};
 
@@ -161,9 +164,11 @@
 		plugin_config *s;
 
 		s = calloc(1, sizeof(plugin_config));
-		s->forwarder    = array_init();
+		s->forwarder = array_init();
+		s->headers   = array_init();
 
 		cv[0].destination = s->forwarder;
+		cv[1].destination = s->headers;
 
 		p->config_storage[i] = s;
 
@@ -182,6 +187,7 @@
 	plugin_config *s = p->config_storage[0];
 
 	PATCH(forwarder);
+	PATCH(headers);
 
 	/* skip the first, the global context */
 	for (i = 1; i < srv->config_context->used; i++) {
@@ -197,6 +203,8 @@
 
 			if (buffer_is_equal_string(du->key, CONST_STR_LEN("extforward.forwarder"))) {
 				PATCH(forwarder);
+			} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("extforward.headers"))) {
+				PATCH(headers);
 			}
 		}
 	}
@@ -311,6 +319,8 @@
 URIHANDLER_FUNC(mod_extforward_uri_handler) {
 	plugin_data *p = p_d;
 	data_string *forwarded = NULL;
+	data_string *ds;
+	size_t k;
 #ifdef HAVE_IPV6
 	char b2[INET6_ADDRSTRLEN + 1];
 	struct addrinfo *addrlist = NULL;
@@ -322,6 +332,8 @@
 #ifdef HAVE_IPV6
 #endif
 
+
+
 	if (!con->request.headers) return HANDLER_GO_ON;
 
 	mod_extforward_patch_connection(srv, con, p);
@@ -331,6 +343,34 @@
 				"-- mod_extforward_uri_handler called");
 	}
 
+/*************************************************************************************************/
+	// p->conf.headers
+	forwarded = NULL;
+	for(k=0; k<p->conf.headers->used; k++) {
+		ds = (data_string *)p->conf.headers->data[k];
+		
+		forwarded = (data_string*)array_get_element(con->request.headers, ds->value->ptr);
+		if(NULL != forwarded) {
+			break;
+		}
+	}
+	
+	if(NULL == forwarded) {
+		if ((NULL == (forwarded = (data_string *) array_get_element(con->request.headers,"X-Forwarded-For")) &&
+			NULL == (forwarded = (data_string *) array_get_element(con->request.headers,  "Forwarded-For"))) || 
+			(p->conf.headers->used > 0)) {
+
+			if (con->conf.log_request_handling) {
+				log_error_write(srv, __FILE__, __LINE__, "s", "no forward header found, skipping");
+			}
+
+			return HANDLER_GO_ON;
+		}
+	}
+	
+/*************************************************************************************************/
+	
+/*	
 	if ((NULL == (forwarded = (data_string *) array_get_element(con->request.headers,"X-Forwarded-For")) &&
 	     NULL == (forwarded = (data_string *) array_get_element(con->request.headers,  "Forwarded-For")))) {
 
@@ -341,7 +381,7 @@
 
 		return HANDLER_GO_ON;
 	}
-
+*/
 	/* if the remote ip itself is not trusted , then do nothing */
 #ifdef HAVE_IPV6
 	dst_addr_str = inet_ntop(con->dst_addr.plain.sa_family,
@@ -367,7 +407,7 @@
 	/* Testing shows that multiple headers and multiple values in one header
 	   come in _reverse_ order. So the first one we get is the last one in the request. */
 	for (i = forward_array->used - 1; i >= 0; i--) {
-		data_string *ds = (data_string *) forward_array->data[i];
+		ds = (data_string *) forward_array->data[i];
 		if (ds) {
 			real_remote_addr = ds->value->ptr;
 			break;
diff -Nur ../lighttpd-1.4.18-original/src/response.c ./src/response.c
--- ../lighttpd-1.4.18-original/src/response.c	2007-04-13 22:47:40.000000000 +0200
+++ ./src/response.c	2007-12-31 15:22:56.000000000 +0100
@@ -137,6 +137,11 @@
 	if (con->mode == DIRECT && con->physical.path->used == 0) {
 		char *qstr;
 
+		size_t i;
+		for(i = 0; i < COMP_LAST_ELEMENT; ++i) {
+			   con->conditional_is_valid[i] = 0;
+		}
+
 		/* we only come here when we have the parse the full request again
 		 *
 		 * a HANDLER_COMEBACK from mod_rewrite and mod_fastcgi might be a