1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  *
  25  * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
  26  */
  27 
  28 /*
  29  * SMB: nt_cancel
  30  *
  31  * This SMB allows a client to cancel a request currently pending at the
  32  * server.
  33  *
  34  * Client Request                     Description
  35  * ================================== =================================
  36  *
  37  * UCHAR WordCount;                   No words are sent (== 0)
  38  * USHORT ByteCount;                  No bytes (==0)
  39  *
  40  * The Sid, Uid, Pid, Tid, and Mid fields of the SMB are used to locate an
  41  * pending server request from this session.  If a pending request is
  42  * found, it is "hurried along" which may result in success or failure of
  43  * the original request.  No other response is generated for this SMB.
  44  */
  45 
  46 #include <smbsrv/smb_kproto.h>
  47 
  48 smb_sdrc_t
  49 smb_pre_nt_cancel(smb_request_t *sr)
  50 {
  51         DTRACE_SMB_START(op__NtCancel, smb_request_t *, sr);
  52         return (SDRC_SUCCESS);
  53 }
  54 
  55 void
  56 smb_post_nt_cancel(smb_request_t *sr)
  57 {
  58         DTRACE_SMB_DONE(op__NtCancel, smb_request_t *, sr);
  59 }
  60 
  61 /*
  62  * Dispatch handler for SMB_COM_NT_CANCEL.
  63  * Note that Cancel does NOT get a response.
  64  *
  65  * SMB NT Cancel has an inherent race with the request being
  66  * cancelled.  See comments at smb_request_cancel().
  67  */
  68 smb_sdrc_t
  69 smb_com_nt_cancel(smb_request_t *sr)
  70 {
  71         struct smb_request *req;
  72         struct smb_session *session;
  73         int cnt = 0;
  74 
  75         session = sr->session;
  76 
  77         smb_slist_enter(&session->s_req_list);
  78         req = smb_slist_head(&session->s_req_list);
  79         while (req) {
  80                 ASSERT(req->sr_magic == SMB_REQ_MAGIC);
  81                 if ((req != sr) &&
  82                     (req->smb_uid == sr->smb_uid) &&
  83                     (req->smb_pid == sr->smb_pid) &&
  84                     (req->smb_tid == sr->smb_tid) &&
  85                     (req->smb_mid == sr->smb_mid)) {
  86                         smb_request_cancel(req);
  87                         cnt++;
  88                 }
  89                 req = smb_slist_next(&session->s_req_list, req);
  90         }
  91         if (cnt != 1) {
  92                 DTRACE_PROBE2(smb__ntcancel__error,
  93                     uint16_t, sr->smb_mid, int, cnt);
  94         }
  95         smb_slist_exit(&session->s_req_list);
  96 
  97         return (SDRC_NO_REPLY);
  98 }
  99 
 100 /*
 101  * This handles an SMB_COM_NT_CANCEL request when seen in the reader.
 102  * (See smb1sr_newrq)  Handle this immediately, rather than
 103  * going through the normal taskq dispatch mechanism.
 104  * Note that Cancel does NOT get a response.
 105  */
 106 int
 107 smb1sr_newrq_cancel(smb_request_t *sr)
 108 {
 109         (void) smb_pre_nt_cancel(sr);
 110         (void) smb_com_nt_cancel(sr);
 111         smb_post_nt_cancel(sr);
 112         return (0);
 113 }