xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb_nt_cancel.c (revision 85f4cb87104c72587029a6e0f1663332c85ba118)
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 }
114