From: Stefan Metzmacher <metze@samba.org>
Date: Fri, 5 Aug 2011 18:34:43 +0000 (+0200)
Subject: s3:smb2_server: make sure we preferr responses over requests on the client socket
X-Git-Url: http://git.samba.org/?p=metze%2Fsamba%2Fwip.git;a=commitdiff_plain;h=286a57cdfc76d02b36f3fb41a24c9e9e3b6c6f09

s3:smb2_server: make sure we preferr responses over requests on the client socket

metze
---

diff --git a/source3/smbd/smb2_server.c b/source3/smbd/smb2_server.c
index 288cc79b545f..3b07f74487a7 100644
--- a/source3/smbd/smb2_server.c
+++ b/source3/smbd/smb2_server.c
@@ -1817,6 +1817,8 @@ void smbd_smb2_request_dispatch_immediate(struct tevent_context *ctx,
 	}
 }
 
+static NTSTATUS smbd_smb2_request_next_incoming(struct smbd_server_connection *sconn);
+
 static void smbd_smb2_request_writev_done(struct tevent_req *subreq)
 {
 	struct smbd_smb2_request *req = tevent_req_callback_data(subreq,
@@ -1824,17 +1826,24 @@ static void smbd_smb2_request_writev_done(struct tevent_req *subreq)
 	struct smbd_server_connection *sconn = req->sconn;
 	int ret;
 	int sys_errno;
+	NTSTATUS status;
 
 	ret = tstream_writev_queue_recv(subreq, &sys_errno);
 	TALLOC_FREE(subreq);
 	TALLOC_FREE(req);
 	if (ret == -1) {
-		NTSTATUS status = map_nt_error_from_unix(sys_errno);
+		status = map_nt_error_from_unix(sys_errno);
 		DEBUG(2,("smbd_smb2_request_writev_done: client write error %s\n",
 			nt_errstr(status)));
 		smbd_server_connection_terminate(sconn, nt_errstr(status));
 		return;
 	}
+
+	status = smbd_smb2_request_next_incoming(sconn);
+	if (!NT_STATUS_IS_OK(status)) {
+		smbd_server_connection_terminate(sconn, nt_errstr(status));
+		return;
+	}
 }
 
 NTSTATUS smbd_smb2_request_done_ex(struct smbd_smb2_request *req,
@@ -2441,12 +2450,47 @@ static NTSTATUS smbd_smb2_request_read_recv(struct tevent_req *req,
 
 static void smbd_smb2_request_incoming(struct tevent_req *subreq);
 
+static NTSTATUS smbd_smb2_request_next_incoming(struct smbd_server_connection *sconn)
+{
+	size_t max_send_queue_len;
+	size_t cur_send_queue_len;
+	struct tevent_req *subreq;
+
+	if (tevent_queue_length(sconn->smb2.recv_queue) > 0) {
+		/*
+		 * if there is already a smbd_smb2_request_read
+		 * pending, we are done.
+		 */
+		return NT_STATUS_OK;
+	}
+
+	max_send_queue_len = MAX(1, sconn->smb2.max_credits/16);
+	cur_send_queue_len = tevent_queue_length(sconn->smb2.send_queue);
+
+	if (cur_send_queue_len > max_send_queue_len) {
+		/*
+		 * if we have a lot of requests to send,
+		 * we wait until they are on the wire until we
+		 * ask for the next request.
+		 */
+		return NT_STATUS_OK;
+	}
+
+	/* ask for the next request */
+	subreq = smbd_smb2_request_read_send(sconn, sconn->smb2.event_ctx, sconn);
+	if (subreq == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	tevent_req_set_callback(subreq, smbd_smb2_request_incoming, sconn);
+
+	return NT_STATUS_OK;
+}
+
 void smbd_smb2_first_negprot(struct smbd_server_connection *sconn,
 			     const uint8_t *inbuf, size_t size)
 {
 	NTSTATUS status;
 	struct smbd_smb2_request *req = NULL;
-	struct tevent_req *subreq;
 
 	DEBUG(10,("smbd_smb2_first_negprot: packet length %u\n",
 		 (unsigned int)size));
@@ -2475,13 +2519,11 @@ void smbd_smb2_first_negprot(struct smbd_server_connection *sconn,
 		return;
 	}
 
-	/* ask for the next request */
-	subreq = smbd_smb2_request_read_send(sconn, sconn->smb2.event_ctx, sconn);
-	if (subreq == NULL) {
-		smbd_server_connection_terminate(sconn, "no memory for reading");
+	status = smbd_smb2_request_next_incoming(sconn);
+	if (!NT_STATUS_IS_OK(status)) {
+		smbd_server_connection_terminate(sconn, nt_errstr(status));
 		return;
 	}
-	tevent_req_set_callback(subreq, smbd_smb2_request_incoming, sconn);
 
 	sconn->num_requests++;
 }
@@ -2533,13 +2575,11 @@ static void smbd_smb2_request_incoming(struct tevent_req *subreq)
 	}
 
 next:
-	/* ask for the next request (this constructs the main loop) */
-	subreq = smbd_smb2_request_read_send(sconn, sconn->smb2.event_ctx, sconn);
-	if (subreq == NULL) {
-		smbd_server_connection_terminate(sconn, "no memory for reading");
+	status = smbd_smb2_request_next_incoming(sconn);
+	if (!NT_STATUS_IS_OK(status)) {
+		smbd_server_connection_terminate(sconn, nt_errstr(status));
 		return;
 	}
-	tevent_req_set_callback(subreq, smbd_smb2_request_incoming, sconn);
 
 	sconn->num_requests++;