Merge r1890605, r1893164, r1893179 from trunk:

  *) core/mod_proxy/mod_ssl:
     Adding `outgoing` flag to conn_rec, indicating a connection is
     initiated by the server to somewhere, in contrast to incoming
     connections from clients.
     Adding 'ap_ssl_bind_outgoing()` function that marks a connection
     as outgoing and is used by mod_proxy instead of the previous
     optional function `ssl_engine_set`. This enables other SSL
     module to secure proxy connections.
     The optional functions `ssl_engine_set`, `ssl_engine_disable` and
     `ssl_proxy_enable` are now provided by the core to have backward
     compatibility with non-httpd modules that might use them. mod_ssl
     itself no longer registers these functions, but keeps them in its
     header for backward compatibility.
     The core provided optional function wrap any registered function
     like it was done for `ssl_is_ssl`.


  *core: clarify comments and use hook API better to check for presence of callbacks.



 * optimizing hook check as suggested by Yann.



Submitted by: icing
Reviewed by: 

Github: closes #203


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1893182 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 41 insertions, 1 deletions

diff --git a/include/ap_mmn.h b/include/ap_mmn.h
index 70447b845e..f874f96f2d 100644
--- a/include/ap_mmn.h
+++ b/include/ap_mmn.h
@@ -577,6 +577,7 @@
  * 20120211.114 (2.4.49-dev) Add optional balancer_manage function.
  * 20120211.115 (2.4.49-dev) Add ap_proxy_get_worker_ex() and
  *                           ap_proxy_define_worker_ex() to mod_proxy.h
+ * 20120211.116 (2.4.49-dev) add conn_rec->outgoing and ap_ssl_bind_outgoing()
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503234UL /* "AP24" */
@@ -584,7 +585,7 @@
 #ifndef MODULE_MAGIC_NUMBER_MAJOR
 #define MODULE_MAGIC_NUMBER_MAJOR 20120211
 #endif
-#define MODULE_MAGIC_NUMBER_MINOR 115                 /* 0...n */
+#define MODULE_MAGIC_NUMBER_MINOR 116                 /* 0...n */
 
 /**
  * Determine if the server's current MODULE_MAGIC_NUMBER is at least a
diff --git a/include/http_ssl.h b/include/http_ssl.h
index 556a58bdb7..0b5379379f 100644
--- a/include/http_ssl.h
+++ b/include/http_ssl.h
@@ -34,6 +34,8 @@
 extern "C" {
 #endif
 
+struct ap_conf_vector_t;
+
 /**
  * This hook allows modules that manage SSL connection to register their
  * inquiry function for checking if a connection is using SSL from them.
@@ -50,6 +52,41 @@ AP_DECLARE_HOOK(int,ssl_conn_is_ssl,(conn_rec *c))
 AP_DECLARE(int) ap_ssl_conn_is_ssl(conn_rec *c);
 
 /**
+ * This hook declares a connection to be outgoing and the configuration that applies to it.
+ * This hook can be called several times in the lifetime of an outgoing connection, e.g.
+ * when it is re-used in different request contexts. It will at least be called after the
+ * connection was created and before the pre-connection hooks is invoked.
+ * All outgoing-connection hooks are run until one returns something other than DECLINE.
+ * if enable_ssl != 0, a hook that sets up SSL for the connection needs to return OK
+ * to prevent subsequent hooks from doing the same.
+ *
+ * @param c The connection on which requests/data are to be sent.
+ * @param dir_conf The directory configuration in which this connection is being used.
+ * @param enable_ssl If != 0, the SSL protocol should be enabled for this connection.
+ * @return DECLINED, OK when ssl was enabled
+ */
+AP_DECLARE_HOOK(int, ssl_bind_outgoing,
+               (conn_rec *c, struct ap_conf_vector_t *dir_conf, int enable_ssl))
+
+/**
+ * Assures the connection is marked as outgoing and invokes the ssl_bind_outgoing hook.
+ * This may be called several times on an outgoing connection with varying dir_conf
+ * values. require_ssl is not allowed to change on the same connection.
+ *
+ * @param c The connection on which requests/data are to be sent.
+ * @param dir_conf The directory configuration in which this connection is being used.
+ * @param require_ssl != 0 iff this connection needs to be secured by SSL/TLS protocol.
+ * @return OK iff ssl was required and is enabled, DECLINED otherwise
+ */
+AP_DECLARE(int) ap_ssl_bind_outgoing(conn_rec *c, struct ap_conf_vector_t *dir_conf,
+                                     int require_ssl);
+
+/**
+ * Return != 0 iff handlers/hooks for outgoing connections are registered.
+ */
+AP_DECLARE(int) ap_ssl_has_outgoing_handlers(void);
+
+/**
  * This hook allows modules to look up SSL related variables for a
  * server/connection/request, depending on what they inquire. Some
  * variables will only be available for a connection/request, for example.
diff --git a/include/httpd.h b/include/httpd.h
index 02cde256ed..d03626a62b 100644
--- a/include/httpd.h
+++ b/include/httpd.h
@@ -1238,6 +1238,8 @@ struct conn_rec {
 
     /** The "real" master connection. NULL if I am the master. */
     conn_rec *master;
+
+    int outgoing;
 };
 
 /**