Merge r645813 from trunk:

* In the case that we fail to read the response line from the backend and if
  we are a reverse proxy request shutdown the connection WITHOUT ANY response
  to trigger a retry by the client if allowed (as for idempotent requests).
  BUT currently we should not do this if the request is the first request on
  a keepalive connection as browsers like seamonkey only display an empty page
  in this case and do not do a retry.

Related to PR 37770

Submitted by: rpluem
Reviewed by: rpluem, jim, fielding

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@657443 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/CHANGES b/CHANGES
index e9dc95f3daf37c7cdf949bce7b39fca5b63e8326..b057d26990d01b7260c7ca64002879f9bdd65e9e 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,10 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.2.9
 
+  *) mod_proxy: Trigger a retry by the client in the case we fail to read the
+     response line from the backend by closing the connection to the client.
+     PR 37770 [Ruediger Pluem]
+
   *) gen_test_char: add double-quote to the list of T_HTTP_TOKEN_STOP.
      PR 9727 [Ville Skytt <ville.skytta iki.fi>]
 

diff --git a/STATUS b/STATUS
index b5639f1c90eb137bb403282662efd64f97177eef..dcfe18261dbf03b74c6b73c34586358317013fb5 100644 (file)
--- a/STATUS
+++ b/STATUS
@@ -90,16 +90,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
- * mod_proxy:  In the case that we fail to read the response line
-   from the backend and if we are a reverse proxy request, shutdown
-   the connection WITHOUT ANY response to trigger a retry by the client
-   if allowed (as for idempotent requests).
-   Trunk version of patch:
-       http://svn.apache.org/viewvc?view=rev&revision=645813
-   Backport version for 2.2.x of patch:
-       Trunk version works
-   +1: rpluem, jim, fielding
-
 * mod_ssl: Fix a memory leak with connections that have zlib compression
   turned on. PR 44975 [Joe Orton, Amund Elstad <Amund.Elstad ist.com>, 
   Dr Stephen Henson <steve openssl.org>]

diff --git a/modules/http/http_filters.c b/modules/http/http_filters.c
index 83e8fb34328f5ec0ac36dc4696540e9652c1570d..2a8761c776436352866b735ebbb99f6bc2bb765a 100644 (file)
--- a/modules/http/http_filters.c
+++ b/modules/http/http_filters.c
@@ -39,6 +39,7 @@
 #include "http_main.h"
 #include "http_request.h"
 #include "http_vhost.h"
+#include "http_connection.h"
 #include "http_log.h"           /* For errors detected in basic auth common
                                  * support code... */
 #include "apr_date.h"           /* For apr_date_parse_http and APR_DATE_BAD */
@@ -1091,6 +1092,7 @@ AP_CORE_DECLARE_NONSTD(apr_status_t) ap_http_header_filter(ap_filter_t *f,
     header_struct h;
     header_filter_ctx *ctx = f->ctx;
     const char *ctype;
+    ap_bucket_error *eb = NULL;
 
     AP_DEBUG_ASSERT(!r->main);
 
@@ -1108,12 +1110,22 @@ AP_CORE_DECLARE_NONSTD(apr_status_t) ap_http_header_filter(ap_filter_t *f,
          e != APR_BRIGADE_SENTINEL(b);
          e = APR_BUCKET_NEXT(e))
     {
-        if (AP_BUCKET_IS_ERROR(e)) {
-            ap_bucket_error *eb = e->data;
-
-            ap_die(eb->status, r);
-            return AP_FILTER_ERROR;
+        if (AP_BUCKET_IS_ERROR(e) && !eb) {
+            eb = e->data;
+            continue;
         }
+        /*
+         * If we see an EOC bucket it is a signal that we should get out
+         * of the way doing nothing.
+         */
+        if (AP_BUCKET_IS_EOC(e)) {
+            ap_remove_output_filter(f);
+            return ap_pass_brigade(f->next, b);
+        }
+    }
+    if (eb) {
+        ap_die(eb->status, r);
+        return AP_FILTER_ERROR;
     }
 
     if (r->assbackwards) {

diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index cc490de5873c8732968f231720ff736cde51db64..5356f161e168fed89c9ede0eecf960ccc6156f2d 100644 (file)
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -1365,6 +1365,38 @@ apr_status_t ap_proxy_http_process_response(apr_pool_t * p, request_rec *r,
             ap_log_rerror(APLOG_MARK, APLOG_ERR, rc, r,
                           "proxy: error reading status line from remote "
                           "server %s", backend->hostname);
+            /*
+             * If we are a reverse proxy request shutdown the connection
+             * WITHOUT ANY response to trigger a retry by the client
+             * if allowed (as for idempotent requests).
+             * BUT currently we should not do this if the request is the
+             * first request on a keepalive connection as browsers like
+             * seamonkey only display an empty page in this case and do
+             * not do a retry.
+             */
+            if (r->proxyreq == PROXYREQ_REVERSE && c->keepalives) {
+                ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+                              "proxy: Closing connection to client because"
+                              " reading from backend server %s failed. Number"
+                              " of keepalives %i", backend->hostname, 
+                              c->keepalives);
+                ap_proxy_backend_broke(r, bb);
+                /*
+                 * Add an EOC bucket to signal the ap_http_header_filter
+                 * that it should get out of our way
+                 */
+                e = ap_bucket_eoc_create(c->bucket_alloc);
+                APR_BRIGADE_INSERT_TAIL(bb, e);
+                ap_pass_brigade(r->output_filters, bb);
+                /* Need to return OK to avoid sending an error message */
+                return OK;
+            }
+            else if (!c->keepalives) {
+                     ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+                                   "proxy: NOT Closing connection to client"
+                                   " although reading from backend server %s"
+                                   " failed.", backend->hostname);
+            }
             return ap_proxyerror(r, HTTP_BAD_GATEWAY,
                                  "Error reading from remote server");
         }