1 /*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source. A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12 /*
13 * Copyright 2018 Nexenta Systems, Inc. All rights reserved.
14 */
15
16 /*
17 * Dispatch function for SMB2_CANCEL
18 */
19
20 #include <smbsrv/smb2_kproto.h>
21
22 static void smb2_cancel_async(smb_request_t *);
23 static void smb2_cancel_sync(smb_request_t *);
24
25 /*
26 * This handles an SMB2_CANCEL request when seen in the reader.
27 * (See smb2sr_newrq) Handle this immediately, rather than
28 * going through the normal taskq dispatch mechanism.
29 * Note that Cancel does NOT get a response.
30 *
31 * Any non-zero return causes disconnect.
32 * SMB2 header is already decoded.
33 */
34 int
35 smb2_newrq_cancel(smb_request_t *sr)
36 {
37
38 /*
39 * If we get SMB2 cancel as part of a compound,
40 * that's a protocol violation. Drop 'em!
41 */
42 if (sr->smb2_next_command != 0)
43 return (EINVAL);
44
45 DTRACE_SMB2_START(op__Cancel, smb_request_t *, sr);
46
47 if (sr->smb2_hdr_flags & SMB2_FLAGS_ASYNC_COMMAND)
48 smb2_cancel_async(sr);
49 else
50 smb2_cancel_sync(sr);
51
52 DTRACE_SMB2_DONE(op__Cancel, smb_request_t *, sr);
53
54 return (0);
55 }
56
57 /*
58 * Dispatch handler for SMB2_CANCEL.
59 * Note that Cancel does NOT get a response.
60 */
61 smb_sdrc_t
62 smb2_cancel(smb_request_t *sr)
63 {
64
65 /*
66 * If we get SMB2 cancel as part of a compound,
67 * that's a protocol violation. Drop 'em!
68 */
69 if (sr->smb2_cmd_hdr != 0 || sr->smb2_next_command != 0)
70 return (SDRC_DROP_VC);
71
72 DTRACE_SMB2_START(op__Cancel, smb_request_t *, sr);
73
74 if (sr->smb2_hdr_flags & SMB2_FLAGS_ASYNC_COMMAND) {
75 smb2_cancel_async(sr);
76 } else {
77 smb2_cancel_sync(sr);
78 }
79
80 DTRACE_SMB2_DONE(op__Cancel, smb_request_t *, sr);
81
82 return (SDRC_NO_REPLY);
83 }
84
85 /*
86 * SMB2 Cancel (sync) has an inherent race with the request being
87 * cancelled. The request may have been received but not yet
88 * executed by a worker thread, in which case we'll mark the
89 * request state as cancelled, and when a worker thread starts
90 * on this request we'll cancel everything in the compound.
91 */
92 static void
93 smb2_cancel_sync(smb_request_t *sr)
94 {
95 struct smb_request *req;
96 struct smb_session *session = sr->session;
97 int cnt = 0;
98
99 if (sr->smb2_messageid == 0)
100 goto failure;
101
102 smb_slist_enter(&session->s_req_list);
103 for (req = smb_slist_head(&session->s_req_list); req != NULL;
104 req = smb_slist_next(&session->s_req_list, req)) {
105
106 /* never cancel self */
107 if (req == sr)
108 continue;
109
110 if (sr->smb2_messageid >= req->smb2_first_msgid &&
111 sr->smb2_messageid < (req->smb2_first_msgid +
112 req->smb2_total_credits)) {
113 smb_request_cancel(req);
114 cnt++;
115 }
116 }
117 smb_slist_exit(&session->s_req_list);
118
119 if (cnt != 1) {
120 failure:
121 DTRACE_PROBE2(smb2__cancel__error,
122 uint64_t, sr->smb2_messageid, int, cnt);
123 #ifdef DEBUG
124 /*
125 * It's somewhat common that we may see a cancel for a
126 * request that has already completed, so report that
127 * only in debug builds.
128 */
129 cmn_err(CE_WARN, "SMB2 cancel failed, "
130 "client=%s, MID=0x%llx",
131 sr->session->ip_addr_str,
132 (u_longlong_t)sr->smb2_messageid);
133 #endif
134 }
135 }
136
137 /*
138 * Note that cancelling an async request doesn't have a race
139 * because the client doesn't learn about the async ID until we
140 * send it to them in an interim reply, and by that point the
141 * request has progressed to the point where smb_cancel can find
142 * the request and cancel it.
143 */
144 static void
145 smb2_cancel_async(smb_request_t *sr)
146 {
147 struct smb_request *req;
148 struct smb_session *session = sr->session;
149 int cnt = 0;
150
151 smb_slist_enter(&session->s_req_list);
152 req = smb_slist_head(&session->s_req_list);
153 while (req) {
154 ASSERT(req->sr_magic == SMB_REQ_MAGIC);
155 if ((req != sr) &&
156 (req->smb2_async_id == sr->smb2_async_id)) {
157 smb_request_cancel(req);
158 cnt++;
159 }
160 req = smb_slist_next(&session->s_req_list, req);
161 }
162 if (cnt != 1) {
163 DTRACE_PROBE2(smb2__cancel__error,
164 uint64_t, sr->smb2_async_id, int, cnt);
165 /*
166 * Not logging here, as this is normal, i.e.
167 * when both a cancel and a handle close
168 * terminates an SMB2_notify request.
169 */
170 }
171 smb_slist_exit(&session->s_req_list);
172 }