adding API to handle #1661 (allow externally created connections)

6 files changed, 163 insertions, 58 deletions

diff --git a/ChangeLog b/ChangeLog
index fa0da138..2a67dd67 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Mar  4 10:24:04 CET 2011
+        Added new API to allow MHD server to initiate connection to
+        client (special use-case for servers behind NAT), thereby
+        addressing #1661 (externally created connections).
+        Releasing libmicrohttpd 0.9.8. -CG
+
 Fri Mar  4 10:07:18 CET 2011
         Avoid using a pipe for signalling as well, just use server
         socket shutdown (also for thread-per-connection). -CG
diff --git a/configure.ac b/configure.ac
index 1b136cf6..b79ee827 100644
--- a/configure.ac
+++ b/configure.ac
@@ -27,9 +27,9 @@ AM_CONFIG_HEADER([MHD_config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AH_TOP([#define _GNU_SOURCE  1])
 
-LIB_VERSION_CURRENT=15
+LIB_VERSION_CURRENT=16
 LIB_VERSION_REVISION=0
-LIB_VERSION_AGE=5
+LIB_VERSION_AGE=6
 AC_SUBST(LIB_VERSION_CURRENT)
 AC_SUBST(LIB_VERSION_REVISION)
 AC_SUBST(LIB_VERSION_AGE)
diff --git a/doc/microhttpd-tutorial.texi b/doc/microhttpd-tutorial.texi
index b4f19a34..020b1e2a 100644
--- a/doc/microhttpd-tutorial.texi
+++ b/doc/microhttpd-tutorial.texi
@@ -3,8 +3,8 @@
 @setfilename microhttpd-tutorial.info
 @set UPDATED 28 Feb 2010
 @set UPDATED-MONTH Feb 2010
-@set EDITION 0.9.7
-@set VERSION 0.9.7
+@set EDITION 0.9.8
+@set VERSION 0.9.8
 @settitle A tutorial for GNU libmicrohttpd
 
 @dircategory GNU Libraries
diff --git a/doc/microhttpd.texi b/doc/microhttpd.texi
index 86ed2481..ab8c5c9e 100644
--- a/doc/microhttpd.texi
+++ b/doc/microhttpd.texi
@@ -9,7 +9,7 @@ header file @file{microhttpd.h}.
 
 @noindent
 
-Copyright @copyright{} 2007, 2008, 2009, 2010 Christian Grothoff
+Copyright @copyright{} 2007, 2008, 2009, 2010, 2011 Christian Grothoff
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
@@ -1100,6 +1100,36 @@ started with the right options for this call.
 @end deftypefun
 
 
+@deftypefun void MHD_add_connection (struct MHD_Daemon *daemon, int client_socket, const struct sockaddr *addr, socklen_t addrlen)
+Add another client connection to the set of connections 
+managed by MHD.  This API is usually not needed (since
+MHD will accept inbound connections on the server socket).
+Use this API in special cases, for example if your HTTP
+server is behind NAT and needs to connect out to the 
+HTTP client.
+
+The given client socket will be managed (and closed!) by MHD after
+this call and must no longer be used directly by the application
+afterwards.
+
+@table @var
+@item daemon 
+daemon that manages the connection
+@item client_socket 
+socket to manage (MHD will expect to receive an HTTP request from this socket next).
+@item addr 
+IP address of the client
+@item addrlen 
+number of bytes in addr
+@end table
+
+This function will return @code{MHD_YES} on success, 
+@code{MHD_NO} if this daemon could
+not handle the connection (i.e. malloc failed, etc).
+The socket will be closed in any case.
+@end deftypefun
+
+
 @c ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 @c -----------------------------------------------------------
diff --git a/src/daemon/daemon.c b/src/daemon/daemon.c
index f12f8207..54b73f9b 100644
--- a/src/daemon/daemon.c
+++ b/src/daemon/daemon.c
@@ -860,60 +860,52 @@ create_thread (pthread_t * thread,
 
 
 /**
- * Accept an incoming connection and create the MHD_Connection object for
- * it.  This function also enforces policy by way of checking with the
- * accept policy callback.
- * 
- * @param daemon handle with the listen socket
- * @return MHD_YES on success
+ * Add another client connection to the set of connections 
+ * managed by MHD.  This API is usually not needed (since
+ * MHD will accept inbound connections on the server socket).
+ * Use this API in special cases, for example if your HTTP
+ * server is behind NAT and needs to connect out to the 
+ * HTTP client.
+ *
+ * The given client socket will be managed (and closed!) by MHD after
+ * this call and must no longer be used directly by the application
+ * afterwards.
+ *
+ * Per-IP connection limits are ignored when using this API.
+ *
+ * @param daemon daemon that manages the connection
+ * @param client_socket socket to manage (MHD will expect
+ *        to receive an HTTP request from this socket next).
+ * @param addr IP address of the client
+ * @param addrlen number of bytes in addr
+ * @return MHD_YES on success, MHD_NO if this daemon could
+ *        not handle the connection (i.e. malloc failed, etc).
+ *        The socket will be closed in any case.
  */
-static int
-MHD_accept_connection (struct MHD_Daemon *daemon)
+int 
+MHD_add_connection (struct MHD_Daemon *daemon, 
+                    int client_socket,
+                    const struct sockaddr *addr,
+                    socklen_t addrlen)
 {
   struct MHD_Connection *connection;
-#if HAVE_INET6
-  struct sockaddr_in6 addrstorage;
-#else
-  struct sockaddr_in addrstorage;
-#endif
-  struct sockaddr *addr = (struct sockaddr *) &addrstorage;
-  socklen_t addrlen;
-  int s;
   int res_thread_create;
 #if OSX
   static int on = 1;
 #endif
 
-  addrlen = sizeof (addrstorage);
-  memset (addr, 0, sizeof (addrstorage));
-
-  s = ACCEPT (daemon->socket_fd, addr, &addrlen);
-  if ((s == -1) || (addrlen <= 0))
-    {
-#if HAVE_MESSAGES
-      /* This could be a common occurance with multiple worker threads */
-      if ((EAGAIN != errno) && (EWOULDBLOCK != errno))
-        MHD_DLOG (daemon, "Error accepting connection: %s\n", STRERROR (errno));
-#endif
-      if (s != -1)
-        {
-          SHUTDOWN (s, SHUT_RDWR);
-          CLOSE (s);
-          /* just in case */
-        }
-      return MHD_NO;
-    }
 #ifndef WINDOWS
-  if ( (s >= FD_SETSIZE) &&
+  if ( (client_socket >= FD_SETSIZE) &&
        (0 == (daemon->options & MHD_USE_POLL)) )
     {
 #if HAVE_MESSAGES
       MHD_DLOG (daemon,
                 "Socket descriptor larger than FD_SETSIZE: %d > %d\n",
-                s,
+                client_socket,
                 FD_SETSIZE);
 #endif
-      CLOSE (s);
+      SHUTDOWN (client_socket, SHUT_RDWR);
+      CLOSE (client_socket);
       return MHD_NO;
     }
 #endif
@@ -932,8 +924,8 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
       MHD_DLOG (daemon,
                 "Server reached connection limit (closing inbound connection)\n");
 #endif
-      SHUTDOWN (s, SHUT_RDWR);
-      CLOSE (s);
+      SHUTDOWN (client_socket, SHUT_RDWR);
+      CLOSE (client_socket);
       return MHD_NO;
     }
 
@@ -946,11 +938,12 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
       MHD_DLOG (daemon, "Connection rejected, closing connection\n");
 #endif
 #endif
-      SHUTDOWN (s, SHUT_RDWR);
-      CLOSE (s);
+      SHUTDOWN (client_socket, SHUT_RDWR);
+      CLOSE (client_socket);
       MHD_ip_limit_del (daemon, addr, addrlen);
       return MHD_YES;
     }
+
 #if OSX
 #ifdef SOL_SOCKET
 #ifdef SO_NOSIGPIPE
@@ -958,14 +951,15 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
 #endif
 #endif
 #endif
+
   connection = malloc (sizeof (struct MHD_Connection));
   if (NULL == connection)
     {
 #if HAVE_MESSAGES
       MHD_DLOG (daemon, "Error allocating memory: %s\n", STRERROR (errno));
 #endif
-      SHUTDOWN (s, SHUT_RDWR);
-      CLOSE (s);
+      SHUTDOWN (client_socket, SHUT_RDWR);
+      CLOSE (client_socket);
       MHD_ip_limit_del (daemon, addr, addrlen);
       return MHD_NO;
     }
@@ -977,15 +971,15 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
 #if HAVE_MESSAGES
       MHD_DLOG (daemon, "Error allocating memory: %s\n", STRERROR (errno));
 #endif
-      SHUTDOWN (s, SHUT_RDWR);
-      CLOSE (s);
+      SHUTDOWN (client_socket, SHUT_RDWR);
+      CLOSE (client_socket);
       MHD_ip_limit_del (daemon, addr, addrlen);
       free (connection);
       return MHD_NO;
     }
   memcpy (connection->addr, addr, addrlen);
   connection->addr_len = addrlen;
-  connection->socket_fd = s;
+  connection->socket_fd = client_socket;
   connection->daemon = daemon;
   connection->last_activity = time (NULL);
 
@@ -1022,8 +1016,8 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
                     "Failed to setup TLS credentials: unknown credential type %d\n",
                     connection->daemon->cred_type);
 #endif
-          SHUTDOWN (s, SHUT_RDWR);
-          CLOSE (s);
+          SHUTDOWN (client_socket, SHUT_RDWR);
+          CLOSE (client_socket);
           MHD_ip_limit_del (daemon, addr, addrlen);
           free (connection->addr);
           free (connection);
@@ -1062,8 +1056,8 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
           MHD_DLOG (daemon, "Failed to create a thread: %s\n",
                     STRERROR (res_thread_create));
 #endif
-          SHUTDOWN (s, SHUT_RDWR);
-          CLOSE (s);
+          SHUTDOWN (client_socket, SHUT_RDWR);
+          CLOSE (client_socket);
           MHD_ip_limit_del (daemon, addr, addrlen);
           free (connection->addr);
           free (connection);
@@ -1073,7 +1067,55 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
   connection->next = daemon->connections;
   daemon->connections = connection;
   daemon->max_connections--;
-  return MHD_YES;
+  return MHD_YES;  
+}
+
+
+/**
+ * Accept an incoming connection and create the MHD_Connection object for
+ * it.  This function also enforces policy by way of checking with the
+ * accept policy callback.
+ * 
+ * @param daemon handle with the listen socket
+ * @return MHD_YES on success
+ */
+static int
+MHD_accept_connection (struct MHD_Daemon *daemon)
+{
+#if HAVE_INET6
+  struct sockaddr_in6 addrstorage;
+#else
+  struct sockaddr_in addrstorage;
+#endif
+  struct sockaddr *addr = (struct sockaddr *) &addrstorage;
+  socklen_t addrlen;
+  int s;
+
+  addrlen = sizeof (addrstorage);
+  memset (addr, 0, sizeof (addrstorage));
+  s = ACCEPT (daemon->socket_fd, addr, &addrlen);
+  if ((s == -1) || (addrlen <= 0))
+    {
+#if HAVE_MESSAGES
+      /* This could be a common occurance with multiple worker threads */
+      if ((EAGAIN != errno) && (EWOULDBLOCK != errno))
+        MHD_DLOG (daemon, "Error accepting connection: %s\n", STRERROR (errno));
+#endif
+      if (s != -1)
+        {
+          SHUTDOWN (s, SHUT_RDWR);
+          CLOSE (s);
+          /* just in case */
+        }
+      return MHD_NO;
+    }
+#if HAVE_MESSAGES
+#if DEBUG_CONNECT
+  MHD_DLOG (daemon, "Accepted connection on socket %d\n", s);
+#endif
+#endif
+  return MHD_add_connection (daemon, s,
+                             addr, addrlen);
 }
 
 /**
diff --git a/src/include/microhttpd.h b/src/include/microhttpd.h
index 3f3b61de..9537c962 100644
--- a/src/include/microhttpd.h
+++ b/src/include/microhttpd.h
@@ -106,7 +106,7 @@ extern "C"
 /**
  * Current version of the library.
  */
-#define MHD_VERSION 0x00090703
+#define MHD_VERSION 0x00090800
 
 /**
  * MHD-internal return code for "YES".
@@ -1035,6 +1035,33 @@ void MHD_stop_daemon (struct MHD_Daemon *daemon);
 
 
 /**
+ * Add another client connection to the set of connections 
+ * managed by MHD.  This API is usually not needed (since
+ * MHD will accept inbound connections on the server socket).
+ * Use this API in special cases, for example if your HTTP
+ * server is behind NAT and needs to connect out to the 
+ * HTTP client.
+ *
+ * The given client socket will be managed (and closed!) by MHD after
+ * this call and must no longer be used directly by the application
+ * afterwards.
+ *
+ * @param daemon daemon that manages the connection
+ * @param client_socket socket to manage (MHD will expect
+ *        to receive an HTTP request from this socket next).
+ * @param addr IP address of the client
+ * @param addrlen number of bytes in addr
+ * @return MHD_YES on success, MHD_NO if this daemon could
+ *        not handle the connection (i.e. malloc failed, etc).
+ *        The socket will be closed in any case.
+ */
+int MHD_add_connection (struct MHD_Daemon *daemon, 
+                        int client_socket,
+                        const struct sockaddr *addr,
+                        socklen_t addrlen);
+
+
+/**
  * Obtain the select sets for this daemon.
  *
  * @param daemon daemon to get sets from