2 * SMB1 (CIFS) version specific operations
4 * Copyright (c) 2012, Jeff Layton <jlayton@redhat.com>
6 * This library is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License v2 as published
8 * by the Free Software Foundation.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
13 * the GNU Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include "cifsproto.h"
22 #include "cifs_debug.h"
26 * An NT cancel request header looks just like the original request except:
28 * The Command is SMB_COM_NT_CANCEL
29 * The WordCount is zeroed out
30 * The ByteCount is zeroed out
32 * This function mangles an existing request buffer into a
33 * SMB_COM_NT_CANCEL request and then sends it.
36 send_nt_cancel(struct TCP_Server_Info
*server
, void *buf
,
37 struct mid_q_entry
*mid
)
40 struct smb_hdr
*in_buf
= (struct smb_hdr
*)buf
;
42 /* -4 for RFC1001 length and +2 for BCC field */
43 in_buf
->smb_buf_length
= cpu_to_be32(sizeof(struct smb_hdr
) - 4 + 2);
44 in_buf
->Command
= SMB_COM_NT_CANCEL
;
45 in_buf
->WordCount
= 0;
48 mutex_lock(&server
->srv_mutex
);
49 rc
= cifs_sign_smb(in_buf
, server
, &mid
->sequence_number
);
51 mutex_unlock(&server
->srv_mutex
);
54 rc
= smb_send(server
, in_buf
, be32_to_cpu(in_buf
->smb_buf_length
));
55 mutex_unlock(&server
->srv_mutex
);
57 cFYI(1, "issued NT_CANCEL for mid %u, rc = %d",
64 cifs_compare_fids(struct cifsFileInfo
*ob1
, struct cifsFileInfo
*ob2
)
66 return ob1
->netfid
== ob2
->netfid
;
70 cifs_read_data_offset(char *buf
)
72 READ_RSP
*rsp
= (READ_RSP
*)buf
;
73 return le16_to_cpu(rsp
->DataOffset
);
77 cifs_read_data_length(char *buf
)
79 READ_RSP
*rsp
= (READ_RSP
*)buf
;
80 return (le16_to_cpu(rsp
->DataLengthHigh
) << 16) +
81 le16_to_cpu(rsp
->DataLength
);
84 static struct mid_q_entry
*
85 cifs_find_mid(struct TCP_Server_Info
*server
, char *buffer
)
87 struct smb_hdr
*buf
= (struct smb_hdr
*)buffer
;
88 struct mid_q_entry
*mid
;
90 spin_lock(&GlobalMid_Lock
);
91 list_for_each_entry(mid
, &server
->pending_mid_q
, qhead
) {
92 if (mid
->mid
== buf
->Mid
&&
93 mid
->mid_state
== MID_REQUEST_SUBMITTED
&&
94 le16_to_cpu(mid
->command
) == buf
->Command
) {
95 spin_unlock(&GlobalMid_Lock
);
99 spin_unlock(&GlobalMid_Lock
);
104 cifs_add_credits(struct TCP_Server_Info
*server
, const unsigned int add
)
106 spin_lock(&server
->req_lock
);
107 server
->credits
+= add
;
109 spin_unlock(&server
->req_lock
);
110 wake_up(&server
->request_q
);
114 cifs_set_credits(struct TCP_Server_Info
*server
, const int val
)
116 spin_lock(&server
->req_lock
);
117 server
->credits
= val
;
118 server
->oplocks
= val
> 1 ? enable_oplocks
: false;
119 spin_unlock(&server
->req_lock
);
123 cifs_get_credits_field(struct TCP_Server_Info
*server
)
125 return &server
->credits
;
129 * Find a free multiplex id (SMB mid). Otherwise there could be
130 * mid collisions which might cause problems, demultiplexing the
131 * wrong response to this request. Multiplex ids could collide if
132 * one of a series requests takes much longer than the others, or
133 * if a very large number of long lived requests (byte range
134 * locks or FindNotify requests) are pending. No more than
135 * 64K-1 requests can be outstanding at one time. If no
136 * mids are available, return zero. A future optimization
137 * could make the combination of mids and uid the key we use
138 * to demultiplex on (rather than mid alone).
139 * In addition to the above check, the cifs demultiplex
140 * code already used the command code as a secondary
141 * check of the frame and if signing is negotiated the
142 * response would be discarded if the mid were the same
143 * but the signature was wrong. Since the mid is not put in the
144 * pending queue until later (when it is about to be dispatched)
145 * we do have to limit the number of outstanding requests
146 * to somewhat less than 64K-1 although it is hard to imagine
147 * so many threads being in the vfs at one time.
150 cifs_get_next_mid(struct TCP_Server_Info
*server
)
153 __u16 last_mid
, cur_mid
;
156 spin_lock(&GlobalMid_Lock
);
158 /* mid is 16 bit only for CIFS/SMB */
159 cur_mid
= (__u16
)((server
->CurrentMid
) & 0xffff);
160 /* we do not want to loop forever */
165 * This nested loop looks more expensive than it is.
166 * In practice the list of pending requests is short,
167 * fewer than 50, and the mids are likely to be unique
168 * on the first pass through the loop unless some request
169 * takes longer than the 64 thousand requests before it
170 * (and it would also have to have been a request that
173 while (cur_mid
!= last_mid
) {
174 struct mid_q_entry
*mid_entry
;
175 unsigned int num_mids
;
182 list_for_each_entry(mid_entry
, &server
->pending_mid_q
, qhead
) {
184 if (mid_entry
->mid
== cur_mid
&&
185 mid_entry
->mid_state
== MID_REQUEST_SUBMITTED
) {
186 /* This mid is in use, try a different one */
193 * if we have more than 32k mids in the list, then something
194 * is very wrong. Possibly a local user is trying to DoS the
195 * box by issuing long-running calls and SIGKILL'ing them. If
196 * we get to 2^16 mids then we're in big trouble as this
197 * function could loop forever.
199 * Go ahead and assign out the mid in this situation, but force
200 * an eventual reconnect to clean out the pending_mid_q.
202 if (num_mids
> 32768)
203 server
->tcpStatus
= CifsNeedReconnect
;
206 mid
= (__u64
)cur_mid
;
207 server
->CurrentMid
= mid
;
212 spin_unlock(&GlobalMid_Lock
);
216 struct smb_version_operations smb1_operations
= {
217 .send_cancel
= send_nt_cancel
,
218 .compare_fids
= cifs_compare_fids
,
219 .setup_request
= cifs_setup_request
,
220 .check_receive
= cifs_check_receive
,
221 .add_credits
= cifs_add_credits
,
222 .set_credits
= cifs_set_credits
,
223 .get_credits_field
= cifs_get_credits_field
,
224 .get_next_mid
= cifs_get_next_mid
,
225 .read_data_offset
= cifs_read_data_offset
,
226 .read_data_length
= cifs_read_data_length
,
227 .map_error
= map_smb_to_linux_error
,
228 .find_mid
= cifs_find_mid
,
229 .check_message
= checkSMB
,
230 .dump_detail
= cifs_dump_detail
,
231 .is_oplock_break
= is_valid_oplock_break
,
234 struct smb_version_values smb1_values
= {
235 .version_string
= SMB1_VERSION_STRING
,
236 .large_lock_type
= LOCKING_ANDX_LARGE_FILES
,
237 .exclusive_lock_type
= 0,
238 .shared_lock_type
= LOCKING_ANDX_SHARED_LOCK
,
239 .unlock_lock_type
= 0,
240 .header_size
= sizeof(struct smb_hdr
),
241 .max_header_size
= MAX_CIFS_HDR_SIZE
,
242 .read_rsp_size
= sizeof(READ_RSP
),