From 05ef6282784495a77f4faf76c0de5bc85dfecf06 Mon Sep 17 00:00:00 2001
From: Werner Koch <wk@gnupg.org>
Date: Tue, 11 Dec 2018 13:39:41 +0100
Subject: [PATCH] dirmngr: Retry another server from the pool on 502, 503, 504.

* dirmngr/ks-engine-hkp.c (handle_send_request_error): Add arg
http_status and handle it.
(ks_hkp_search): Get http_status froms end_request and pass on to
handle_send_request_error.
(ks_hkp_get): Ditto.
(ks_hkp_put): Ditto.
--

GnuPG-bug-id: 4175
Signed-off-by: Werner Koch <wk@gnupg.org>
---
 dirmngr/ks-engine-hkp.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/dirmngr/ks-engine-hkp.c b/dirmngr/ks-engine-hkp.c
index 1b14a2e6a..149de9425 100644
--- a/dirmngr/ks-engine-hkp.c
+++ b/dirmngr/ks-engine-hkp.c
@@ -1352,7 +1352,7 @@ send_request (ctrl_t ctrl, const char *request, const char *hostportstr,
    down to zero. */
 static int
 handle_send_request_error (ctrl_t ctrl, gpg_error_t err, const char *request,
-                           unsigned int *tries_left)
+                           unsigned int http_status, unsigned int *tries_left)
 {
   int retry = 0;
 
@@ -1395,6 +1395,27 @@ handle_send_request_error (ctrl_t ctrl, gpg_error_t err, const char *request,
         }
       break;
 
+    case GPG_ERR_NO_DATA:
+      {
+        switch (http_status)
+          {
+          case 502: /* Bad Gateway  */
+            log_info ("marking host dead due to a %u (%s)\n",
+                      http_status, http_status2string (http_status));
+            if (mark_host_dead (request) && *tries_left)
+              retry = 1;
+            break;
+
+          case 503: /* Service Unavailable */
+          case 504: /* Gateway Timeout    */
+            log_info ("selecting a different host due to a %u (%s)",
+                      http_status, http_status2string (http_status));
+            retry = 1;
+            break;
+          }
+      }
+      break;
+
     default:
       break;
     }
@@ -1423,6 +1444,7 @@ ks_hkp_search (ctrl_t ctrl, parsed_uri_t uri, const char *pattern,
   int reselect;
   unsigned int httpflags;
   char *httphost = NULL;
+  unsigned int http_status;
   unsigned int tries = SEND_REQUEST_RETRIES;
 
   *r_fp = NULL;
@@ -1504,12 +1526,14 @@ ks_hkp_search (ctrl_t ctrl, parsed_uri_t uri, const char *pattern,
 
   /* Send the request.  */
   err = send_request (ctrl, request, hostport, httphost, httpflags,
-                      NULL, NULL, &fp, r_http_status);
-  if (handle_send_request_error (ctrl, err, request, &tries))
+                      NULL, NULL, &fp, &http_status);
+  if (handle_send_request_error (ctrl, err, request, http_status, &tries))
     {
       reselect = 1;
       goto again;
     }
+  if (r_http_status)
+    *r_http_status = http_status;
   if (err)
     {
       if (gpg_err_code (err) == GPG_ERR_NO_DATA)
@@ -1571,6 +1595,7 @@ ks_hkp_get (ctrl_t ctrl, parsed_uri_t uri, const char *keyspec, estream_t *r_fp)
   int reselect;
   char *httphost = NULL;
   unsigned int httpflags;
+  unsigned int http_status;
   unsigned int tries = SEND_REQUEST_RETRIES;
 
   *r_fp = NULL;
@@ -1643,8 +1668,8 @@ ks_hkp_get (ctrl_t ctrl, parsed_uri_t uri, const char *keyspec, estream_t *r_fp)
 
   /* Send the request.  */
   err = send_request (ctrl, request, hostport, httphost, httpflags,
-                      NULL, NULL, &fp, NULL);
-  if (handle_send_request_error (ctrl, err, request, &tries))
+                      NULL, NULL, &fp, &http_status);
+  if (handle_send_request_error (ctrl, err, request, http_status, &tries))
     {
       reselect = 1;
       goto again;
@@ -1718,6 +1743,7 @@ ks_hkp_put (ctrl_t ctrl, parsed_uri_t uri, const void *data, size_t datalen)
   int reselect;
   char *httphost = NULL;
   unsigned int httpflags;
+  unsigned int http_status;
   unsigned int tries = SEND_REQUEST_RETRIES;
 
   parm.datastring = NULL;
@@ -1756,8 +1782,8 @@ ks_hkp_put (ctrl_t ctrl, parsed_uri_t uri, const void *data, size_t datalen)
 
   /* Send the request.  */
   err = send_request (ctrl, request, hostport, httphost, 0,
-                      put_post_cb, &parm, &fp, NULL);
-  if (handle_send_request_error (ctrl, err, request, &tries))
+                      put_post_cb, &parm, &fp, &http_status);
+  if (handle_send_request_error (ctrl, err, request, http_status, &tries))
     {
       reselect = 1;
       goto again;