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1/*
2 * An implementation of file copy service.
3 *
4 * Copyright (C) 2014, Microsoft, Inc.
5 *
6 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
15 * NON INFRINGEMENT. See the GNU General Public License for more
16 * details.
17 *
18 */
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/nls.h>
23#include <linux/workqueue.h>
24#include <linux/hyperv.h>
25#include <linux/sched.h>
26
27#include "hyperv_vmbus.h"
28#include "hv_utils_transport.h"
29
30#define WIN8_SRV_MAJOR 1
31#define WIN8_SRV_MINOR 1
32#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
33
34/*
35 * Global state maintained for transaction that is being processed.
36 * For a class of integration services, including the "file copy service",
37 * the specified protocol is a "request/response" protocol which means that
38 * there can only be single outstanding transaction from the host at any
39 * given point in time. We use this to simplify memory management in this
40 * driver - we cache and process only one message at a time.
41 *
42 * While the request/response protocol is guaranteed by the host, we further
43 * ensure this by serializing packet processing in this driver - we do not
44 * read additional packets from the VMBUs until the current packet is fully
45 * handled.
46 */
47
48static struct {
49 int state; /* hvutil_device_state */
50 int recv_len; /* number of bytes received. */
51 struct hv_fcopy_hdr *fcopy_msg; /* current message */
52 struct vmbus_channel *recv_channel; /* chn we got the request */
53 u64 recv_req_id; /* request ID. */
54} fcopy_transaction;
55
56static void fcopy_respond_to_host(int error);
57static void fcopy_send_data(struct work_struct *dummy);
58static void fcopy_timeout_func(struct work_struct *dummy);
59static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
60static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
61static const char fcopy_devname[] = "vmbus/hv_fcopy";
62static u8 *recv_buffer;
63static struct hvutil_transport *hvt;
64/*
65 * This state maintains the version number registered by the daemon.
66 */
67static int dm_reg_value;
68
69static void fcopy_poll_wrapper(void *channel)
70{
71 /* Transaction is finished, reset the state here to avoid races. */
72 fcopy_transaction.state = HVUTIL_READY;
73 hv_fcopy_onchannelcallback(channel);
74}
75
76static void fcopy_timeout_func(struct work_struct *dummy)
77{
78 /*
79 * If the timer fires, the user-mode component has not responded;
80 * process the pending transaction.
81 */
82 fcopy_respond_to_host(HV_E_FAIL);
83 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
84}
85
86static int fcopy_handle_handshake(u32 version)
87{
88 u32 our_ver = FCOPY_CURRENT_VERSION;
89
90 switch (version) {
91 case FCOPY_VERSION_0:
92 /* Daemon doesn't expect us to reply */
93 dm_reg_value = version;
94 break;
95 case FCOPY_VERSION_1:
96 /* Daemon expects us to reply with our own version */
97 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
98 return -EFAULT;
99 dm_reg_value = version;
100 break;
101 default:
102 /*
103 * For now we will fail the registration.
104 * If and when we have multiple versions to
105 * deal with, we will be backward compatible.
106 * We will add this code when needed.
107 */
108 return -EINVAL;
109 }
110 pr_debug("FCP: userspace daemon ver. %d registered\n", version);
111 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
112 return 0;
113}
114
115static void fcopy_send_data(struct work_struct *dummy)
116{
117 struct hv_start_fcopy *smsg_out = NULL;
118 int operation = fcopy_transaction.fcopy_msg->operation;
119 struct hv_start_fcopy *smsg_in;
120 void *out_src;
121 int rc, out_len;
122
123 /*
124 * The strings sent from the host are encoded in
125 * in utf16; convert it to utf8 strings.
126 * The host assures us that the utf16 strings will not exceed
127 * the max lengths specified. We will however, reserve room
128 * for the string terminating character - in the utf16s_utf8s()
129 * function we limit the size of the buffer where the converted
130 * string is placed to W_MAX_PATH -1 to guarantee
131 * that the strings can be properly terminated!
132 */
133
134 switch (operation) {
135 case START_FILE_COPY:
136 out_len = sizeof(struct hv_start_fcopy);
137 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
138 if (!smsg_out)
139 return;
140
141 smsg_out->hdr.operation = operation;
142 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
143
144 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
145 UTF16_LITTLE_ENDIAN,
146 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
147
148 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
149 UTF16_LITTLE_ENDIAN,
150 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
151
152 smsg_out->copy_flags = smsg_in->copy_flags;
153 smsg_out->file_size = smsg_in->file_size;
154 out_src = smsg_out;
155 break;
156
157 default:
158 out_src = fcopy_transaction.fcopy_msg;
159 out_len = fcopy_transaction.recv_len;
160 break;
161 }
162
163 fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
164 rc = hvutil_transport_send(hvt, out_src, out_len);
165 if (rc) {
166 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
167 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
168 fcopy_respond_to_host(HV_E_FAIL);
169 fcopy_transaction.state = HVUTIL_READY;
170 }
171 }
172 kfree(smsg_out);
173
174 return;
175}
176
177/*
178 * Send a response back to the host.
179 */
180
181static void
182fcopy_respond_to_host(int error)
183{
184 struct icmsg_hdr *icmsghdr;
185 u32 buf_len;
186 struct vmbus_channel *channel;
187 u64 req_id;
188
189 /*
190 * Copy the global state for completing the transaction. Note that
191 * only one transaction can be active at a time. This is guaranteed
192 * by the file copy protocol implemented by the host. Furthermore,
193 * the "transaction active" state we maintain ensures that there can
194 * only be one active transaction at a time.
195 */
196
197 buf_len = fcopy_transaction.recv_len;
198 channel = fcopy_transaction.recv_channel;
199 req_id = fcopy_transaction.recv_req_id;
200
201 icmsghdr = (struct icmsg_hdr *)
202 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
203
204 if (channel->onchannel_callback == NULL)
205 /*
206 * We have raced with util driver being unloaded;
207 * silently return.
208 */
209 return;
210
211 icmsghdr->status = error;
212 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
213 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
214 VM_PKT_DATA_INBAND, 0);
215}
216
217void hv_fcopy_onchannelcallback(void *context)
218{
219 struct vmbus_channel *channel = context;
220 u32 recvlen;
221 u64 requestid;
222 struct hv_fcopy_hdr *fcopy_msg;
223 struct icmsg_hdr *icmsghdr;
224 struct icmsg_negotiate *negop = NULL;
225 int util_fw_version;
226 int fcopy_srv_version;
227
228 if (fcopy_transaction.state > HVUTIL_READY)
229 return;
230
231 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
232 &requestid);
233 if (recvlen <= 0)
234 return;
235
236 icmsghdr = (struct icmsg_hdr *)&recv_buffer[
237 sizeof(struct vmbuspipe_hdr)];
238 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
239 util_fw_version = UTIL_FW_VERSION;
240 fcopy_srv_version = WIN8_SRV_VERSION;
241 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
242 util_fw_version, fcopy_srv_version);
243 } else {
244 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
245 sizeof(struct vmbuspipe_hdr) +
246 sizeof(struct icmsg_hdr)];
247
248 /*
249 * Stash away this global state for completing the
250 * transaction; note transactions are serialized.
251 */
252
253 fcopy_transaction.recv_len = recvlen;
254 fcopy_transaction.recv_req_id = requestid;
255 fcopy_transaction.fcopy_msg = fcopy_msg;
256
257 if (fcopy_transaction.state < HVUTIL_READY) {
258 /* Userspace is not registered yet */
259 fcopy_respond_to_host(HV_E_FAIL);
260 return;
261 }
262 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
263
264 /*
265 * Send the information to the user-level daemon.
266 */
267 schedule_work(&fcopy_send_work);
268 schedule_delayed_work(&fcopy_timeout_work,
269 HV_UTIL_TIMEOUT * HZ);
270 return;
271 }
272 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
273 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
274 VM_PKT_DATA_INBAND, 0);
275}
276
277/* Callback when data is received from userspace */
278static int fcopy_on_msg(void *msg, int len)
279{
280 int *val = (int *)msg;
281
282 if (len != sizeof(int))
283 return -EINVAL;
284
285 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
286 return fcopy_handle_handshake(*val);
287
288 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
289 return -EINVAL;
290
291 /*
292 * Complete the transaction by forwarding the result
293 * to the host. But first, cancel the timeout.
294 */
295 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
296 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
297 fcopy_respond_to_host(*val);
298 hv_poll_channel(fcopy_transaction.recv_channel,
299 fcopy_poll_wrapper);
300 }
301
302 return 0;
303}
304
305static void fcopy_on_reset(void)
306{
307 /*
308 * The daemon has exited; reset the state.
309 */
310 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
311
312 if (cancel_delayed_work_sync(&fcopy_timeout_work))
313 fcopy_respond_to_host(HV_E_FAIL);
314}
315
316int hv_fcopy_init(struct hv_util_service *srv)
317{
318 recv_buffer = srv->recv_buffer;
319 fcopy_transaction.recv_channel = srv->channel;
320
321 /*
322 * When this driver loads, the user level daemon that
323 * processes the host requests may not yet be running.
324 * Defer processing channel callbacks until the daemon
325 * has registered.
326 */
327 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
328
329 hvt = hvutil_transport_init(fcopy_devname, 0, 0,
330 fcopy_on_msg, fcopy_on_reset);
331 if (!hvt)
332 return -EFAULT;
333
334 return 0;
335}
336
337void hv_fcopy_deinit(void)
338{
339 fcopy_transaction.state = HVUTIL_DEVICE_DYING;
340 cancel_delayed_work_sync(&fcopy_timeout_work);
341 hvutil_transport_destroy(hvt);
342}