From: Ruediger Pluem <rpluem@apache.org>
Date: Tue, 9 Sep 2008 07:25:56 +0000 (+0000)
Subject: * If CPING fails retry once more with a fresh TCP connection. If this fails
X-Git-Tag: 2.3.0~312
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a5ce4c218b67168357fc300cb765ed0b1a2b5882;p=apache

* If CPING fails retry once more with a fresh TCP connection. If this fails
  as well give up.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@693392 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/modules/proxy/mod_proxy_ajp.c b/modules/proxy/mod_proxy_ajp.c
index 4988bbc53c..1627b8ffa7 100644
--- a/modules/proxy/mod_proxy_ajp.c
+++ b/modules/proxy/mod_proxy_ajp.c
@@ -554,6 +554,7 @@ static int proxy_ajp_handler(request_rec *r, proxy_worker *worker,
     conn_rec *origin = NULL;
     proxy_conn_rec *backend = NULL;
     const char *scheme = "AJP";
+    int retry;
     proxy_dir_conf *dconf = ap_get_module_config(r->per_dir_config,
                                                  &proxy_module);
 
@@ -597,43 +598,53 @@ static int proxy_ajp_handler(request_rec *r, proxy_worker *worker,
     backend->is_ssl = 0;
     backend->close = 0;
 
-    /* Step One: Determine Who To Connect To */
-    status = ap_proxy_determine_connection(p, r, conf, worker, backend,
-                                           uri, &url, proxyname, proxyport,
-                                           server_portstr,
-                                           sizeof(server_portstr));
-
-    if (status != OK)
-        goto cleanup;
-
-    /* Step Two: Make the Connection */
-    if (ap_proxy_connect_backend(scheme, backend, worker, r->server)) {
-        ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
-                     "proxy: AJP: failed to make connection to backend: %s",
-                     backend->hostname);
-        status = HTTP_SERVICE_UNAVAILABLE;
-        goto cleanup;
-    }
+    retry = 0;
+    while (retry < 2) {
+        /* Step One: Determine Who To Connect To */
+        status = ap_proxy_determine_connection(p, r, conf, worker, backend,
+                                               uri, &url, proxyname, proxyport,
+                                               server_portstr,
+                                               sizeof(server_portstr));
 
-    /* Handle CPING/CPONG */
-    if (worker->ping_timeout_set) {
-        status = ajp_handle_cping_cpong(backend->sock, r,
-                                        worker->ping_timeout);
-        if (status != APR_SUCCESS) {
-            backend->close++;
-            ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
-                         "proxy: AJP: cping/cpong failed to %pI (%s)",
-                         worker->cp->addr,
-                         worker->hostname);
+        if (status != OK)
+            break;
+
+        /* Step Two: Make the Connection */
+        if (ap_proxy_connect_backend(scheme, backend, worker, r->server)) {
+            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                         "proxy: AJP: failed to make connection to backend: %s",
+                         backend->hostname);
             status = HTTP_SERVICE_UNAVAILABLE;
-            goto cleanup;
+            break;
+        }
+
+        /* Handle CPING/CPONG */
+        if (worker->ping_timeout_set) {
+            status = ajp_handle_cping_cpong(backend->sock, r,
+                                            worker->ping_timeout);
+            /*
+             * In case the CPING / CPONG failed for the first time we might be
+             * just out of luck and got a faulty backend connection, but the
+             * backend might be healthy nevertheless. So ensure that the backend
+             * TCP connection gets closed and try it once again.
+             */
+            if (status != APR_SUCCESS) {
+                backend->close++;
+                ap_log_error(APLOG_MARK, APLOG_ERR, status, r->server,
+                             "proxy: AJP: cping/cpong failed to %pI (%s)",
+                             worker->cp->addr,
+                             worker->hostname);
+                status = HTTP_SERVICE_UNAVAILABLE;
+                retry++;
+                continue;
+            }
         }
+        /* Step Three: Process the Request */
+        status = ap_proxy_ajp_request(p, r, backend, origin, dconf, uri, url,
+                                      server_portstr);
+        break;
     }
-    /* Step Three: Process the Request */
-    status = ap_proxy_ajp_request(p, r, backend, origin, dconf, uri, url,
-                                  server_portstr);
 
-cleanup:
     /* Do not close the socket */
     ap_proxy_release_connection(scheme, backend, r->server);
     return status;