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

[metze/samba/wip.git] / source3 / smbd / smb2_server.c

diff --git a/source3/smbd/smb2_server.c b/source3/smbd/smb2_server.c
index 11b5ed8bf03d18378b75267fd655f88c6525fa04..3b07f74487a7c071f93380a376a1634443e9b8d2 100644 (file)
--- a/source3/smbd/smb2_server.c
+++ b/source3/smbd/smb2_server.c
@@ -455,9 +455,30 @@ static void smb2_set_operation_credit(struct smbd_server_connection *sconn,
 
        SMB_ASSERT(sconn->smb2.max_credits >= sconn->smb2.credits_granted);
 
-       /* Remember what we gave out. */
-       credits_granted = MIN(credits_requested, (sconn->smb2.max_credits -
-               sconn->smb2.credits_granted));
+       if (credits_requested) {
+               uint16_t modified_credits_requested;
+               uint32_t multiplier;
+
+               /*
+                * Split up max_credits into 1/16ths, and then scale
+                * the requested credits by how many 16ths have been
+                * currently granted. Less than 1/16th == grant all
+                * requested (100%), scale down as more have been
+                * granted. Never ask for less than 1 as the client
+                * asked for at least 1. JRA.
+                */
+
+               multiplier = 16 - (((sconn->smb2.credits_granted * 16) / sconn->smb2.max_credits) % 16);
+
+               modified_credits_requested = (multiplier * credits_requested) / 16;
+               if (modified_credits_requested == 0) {
+                       modified_credits_requested = 1;
+               }
+
+               /* Remember what we gave out. */
+               credits_granted = MIN(modified_credits_requested,
+                                       (sconn->smb2.max_credits - sconn->smb2.credits_granted));
+       }
 
        if (credits_granted == 0 && sconn->smb2.credits_granted == 0) {
                /* First negprot packet, or ensure the client credits can
@@ -1796,6 +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,
@@ -1803,17 +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,
@@ -2420,12 +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));
@@ -2454,13 +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++;
 }
@@ -2512,13 +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++;