Fix evdns_cancel to alert callback and free associated RAM.

Also, we add a test to make sure evdns_cancel is working properly.

svn:r1139

evdns.c

@@ -595,15 +595,19 @@ request_trans_id_set(struct evdns_request *const req, const u16 trans_id) {
 static void
 request_finished(struct evdns_request *const req, struct evdns_request **head) {
 	struct evdns_base *base = req->base;
+	int was_inflight = (head != &base->req_waiting_head);
 	if (head)
 		evdns_request_remove(req, head);
 
 	log(EVDNS_LOG_DEBUG, "Removing timeout for request %lx",
 	    (unsigned long) req);
-	evtimer_del(&req->timeout_event);
-
 	search_request_finished(req);
-	base->global_requests_inflight--;
+	if (was_inflight) {
+		evtimer_del(&req->timeout_event);
+		base->global_requests_inflight--;
+	} else {
+		base->global_requests_waiting--;
+	}
 
 	if (!req->request_appended) {
 		/* need to free the request data on it's own */
@@ -2471,15 +2475,16 @@ request_submit(struct evdns_request *const req) {
 void
 evdns_cancel_request(struct evdns_base *base, struct evdns_request *req)
 {
-        /* XXX Does anything ever free the request */
+	if (!base)
+		base = req->base;
+
+	reply_callback(req, 0, DNS_ERR_CANCEL, NULL);
 	if (req->ns) {
 		/* remove from inflight queue */
-		evdns_request_remove(req, &REQ_HEAD(base, req->trans_id));
+		request_finished(req, &REQ_HEAD(base, req->trans_id));
-		--base->global_requests_inflight;
 	} else {
 		/* remove from global_waiting head */
-		evdns_request_remove(req, &base->req_waiting_head);
+		request_finished(req, &base->req_waiting_head);
-		--base->global_requests_waiting;
 	}
 }
 
@@ -3374,6 +3379,7 @@ evdns_err_to_string(int err)
 	case DNS_ERR_UNKNOWN: return "unknown";
 	case DNS_ERR_TIMEOUT: return "request timed out";
 	case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
+	case DNS_ERR_CANCEL: return "dns request canceled";
 	default: return "[Unknown error code]";
     }
 }

include/event2/dns.h

@@ -187,8 +187,10 @@ extern "C" {
 #define DNS_ERR_UNKNOWN 66
 /** Communication with the server timed out */
 #define DNS_ERR_TIMEOUT 67
-/** The request was canceled because the DNS subsystem was shut down. */
+/** The request was cancelled because the DNS subsystem was shut down. */
 #define DNS_ERR_SHUTDOWN 68
+/** The request was cancelled via a call to evdns_cancel_request */
+#define DNS_ERR_CANCEL 69
 
 #define DNS_IPv4_A 1
 #define DNS_PTR 2

test/regress_dns.c

@@ -66,6 +66,7 @@
 #include "regress.h"
 
 static int dns_ok = 0;
+static int dns_got_cancel = 0;
 static int dns_err = 0;
 
 static void
@@ -244,6 +245,12 @@ dns_server_request_cb(struct evdns_server_request *req, void *data)
 												   "ZZ.EXAMPLE.COM", 54321);
 			if (r<0)
 				dns_ok = 0;
+                } else if (req->questions[i]->type == EVDNS_TYPE_A &&
+		    req->questions[i]->dns_question_class == EVDNS_CLASS_INET &&
+		    !strcasecmp(req->questions[i]->name, "drop.example.com")) {
+			if (evdns_server_request_drop(req)<0)
+				dns_ok = 0;
+			return;
 		} else {
 			fprintf(stdout, "Unexpected question %d %d \"%s\" ",
 					req->questions[i]->type,
@@ -261,8 +268,16 @@ dns_server_request_cb(struct evdns_server_request *req, void *data)
 
 static void
 dns_server_gethostbyname_cb(int result, char type, int count, int ttl,
-							void *addresses, void *arg)
+    void *addresses, void *arg)
 {
+	if (result == DNS_ERR_CANCEL) {
+		if (arg != (void*)(char*)90909) {
+			fprintf(stdout, "Unexpected cancelation");
+			dns_ok = 0;
+		}
+		dns_got_cancel = 1;
+		goto out;
+	}
 	if (result != DNS_ERR_NONE) {
 		fprintf(stdout, "Unexpected result %d. ", result);
 		dns_ok = 0;
@@ -326,14 +341,18 @@ dns_server(void)
 	struct sockaddr_in my_addr;
 	struct evdns_server_port *port=NULL;
 	struct in_addr resolve_addr;
+	struct evdns_base *base=NULL;
+	struct evdns_request *req=NULL;
 
 	dns_ok = 1;
 
+	base = evdns_base_new(NULL, 0);
+
 	/* Add ourself as the only nameserver, and make sure we really are
 	 * the only nameserver. */
-	evdns_nameserver_ip_add("127.0.0.1:35353");
+	evdns_base_nameserver_ip_add(base, "127.0.0.1:35353");
 
-	tt_int_op(evdns_count_nameservers(), ==, 1);
+	tt_int_op(evdns_base_count_nameservers(base), ==, 1);
 	/* Now configure a nameserver port. */
 	sock = socket(AF_INET, SOCK_DGRAM, 0);
         if (sock<=0) {
@@ -351,17 +370,23 @@ dns_server(void)
 	}
 	port = evdns_add_server_port(sock, 0, dns_server_request_cb, NULL);
 
-	/* Send two queries. */
+	/* Send some queries. */
-	evdns_resolve_ipv4("zz.example.com", DNS_QUERY_NO_SEARCH,
+	evdns_base_resolve_ipv4(base, "zz.example.com", DNS_QUERY_NO_SEARCH,
 					   dns_server_gethostbyname_cb, NULL);
-	evdns_resolve_ipv6("zz.example.com", DNS_QUERY_NO_SEARCH,
+	evdns_base_resolve_ipv6(base, "zz.example.com", DNS_QUERY_NO_SEARCH,
 					   dns_server_gethostbyname_cb, NULL);
 	resolve_addr.s_addr = htonl(0xc0a80b0bUL); /* 192.168.11.11 */
-	evdns_resolve_reverse(&resolve_addr, 0,
+	evdns_base_resolve_reverse(base, &resolve_addr, 0,
             dns_server_gethostbyname_cb, NULL);
+	req = evdns_base_resolve_ipv4(base,
+	    "drop.example.com", DNS_QUERY_NO_SEARCH,
+	    dns_server_gethostbyname_cb, (void*)(char*)90909);
+
+	evdns_cancel_request(base, req);
 
 	event_dispatch();
 
+	tt_assert(dns_got_cancel);
         test_ok = dns_ok;
 
 end:
@@ -370,6 +395,8 @@ end:
 	evdns_shutdown(0); /* remove ourself as nameserver. */
         if (sock >= 0)
                 EVUTIL_CLOSESOCKET(sock);
+	if (base)
+		evdns_base_free(base, 0);
 }