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
48 static 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
56 static void fcopy_respond_to_host(int error);
57 static void fcopy_send_data(struct work_struct *dummy);
58 static void fcopy_timeout_func(struct work_struct *dummy);
59 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
60 static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
61 static const char fcopy_devname[] = "vmbus/hv_fcopy";
62 static u8 *recv_buffer;
63 static struct hvutil_transport *hvt;
64 static struct completion release_event;
65 /*
66 * This state maintains the version number registered by the daemon.
67 */
68 static int dm_reg_value;
69
fcopy_poll_wrapper(void * channel)70 static void fcopy_poll_wrapper(void *channel)
71 {
72 /* Transaction is finished, reset the state here to avoid races. */
73 fcopy_transaction.state = HVUTIL_READY;
74 hv_fcopy_onchannelcallback(channel);
75 }
76
fcopy_timeout_func(struct work_struct * dummy)77 static void fcopy_timeout_func(struct work_struct *dummy)
78 {
79 /*
80 * If the timer fires, the user-mode component has not responded;
81 * process the pending transaction.
82 */
83 fcopy_respond_to_host(HV_E_FAIL);
84 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
85 }
86
fcopy_handle_handshake(u32 version)87 static int fcopy_handle_handshake(u32 version)
88 {
89 u32 our_ver = FCOPY_CURRENT_VERSION;
90
91 switch (version) {
92 case FCOPY_VERSION_0:
93 /* Daemon doesn't expect us to reply */
94 dm_reg_value = version;
95 break;
96 case FCOPY_VERSION_1:
97 /* Daemon expects us to reply with our own version */
98 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
99 return -EFAULT;
100 dm_reg_value = version;
101 break;
102 default:
103 /*
104 * For now we will fail the registration.
105 * If and when we have multiple versions to
106 * deal with, we will be backward compatible.
107 * We will add this code when needed.
108 */
109 return -EINVAL;
110 }
111 pr_debug("FCP: userspace daemon ver. %d registered\n", version);
112 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
113 return 0;
114 }
115
fcopy_send_data(struct work_struct * dummy)116 static void fcopy_send_data(struct work_struct *dummy)
117 {
118 struct hv_start_fcopy *smsg_out = NULL;
119 int operation = fcopy_transaction.fcopy_msg->operation;
120 struct hv_start_fcopy *smsg_in;
121 void *out_src;
122 int rc, out_len;
123
124 /*
125 * The strings sent from the host are encoded in
126 * in utf16; convert it to utf8 strings.
127 * The host assures us that the utf16 strings will not exceed
128 * the max lengths specified. We will however, reserve room
129 * for the string terminating character - in the utf16s_utf8s()
130 * function we limit the size of the buffer where the converted
131 * string is placed to W_MAX_PATH -1 to guarantee
132 * that the strings can be properly terminated!
133 */
134
135 switch (operation) {
136 case START_FILE_COPY:
137 out_len = sizeof(struct hv_start_fcopy);
138 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
139 if (!smsg_out)
140 return;
141
142 smsg_out->hdr.operation = operation;
143 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
144
145 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
146 UTF16_LITTLE_ENDIAN,
147 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
148
149 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
150 UTF16_LITTLE_ENDIAN,
151 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
152
153 smsg_out->copy_flags = smsg_in->copy_flags;
154 smsg_out->file_size = smsg_in->file_size;
155 out_src = smsg_out;
156 break;
157
158 case WRITE_TO_FILE:
159 out_src = fcopy_transaction.fcopy_msg;
160 out_len = sizeof(struct hv_do_fcopy);
161 break;
162 default:
163 out_src = fcopy_transaction.fcopy_msg;
164 out_len = fcopy_transaction.recv_len;
165 break;
166 }
167
168 fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
169 rc = hvutil_transport_send(hvt, out_src, out_len);
170 if (rc) {
171 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
172 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
173 fcopy_respond_to_host(HV_E_FAIL);
174 fcopy_transaction.state = HVUTIL_READY;
175 }
176 }
177 kfree(smsg_out);
178
179 return;
180 }
181
182 /*
183 * Send a response back to the host.
184 */
185
186 static void
fcopy_respond_to_host(int error)187 fcopy_respond_to_host(int error)
188 {
189 struct icmsg_hdr *icmsghdr;
190 u32 buf_len;
191 struct vmbus_channel *channel;
192 u64 req_id;
193
194 /*
195 * Copy the global state for completing the transaction. Note that
196 * only one transaction can be active at a time. This is guaranteed
197 * by the file copy protocol implemented by the host. Furthermore,
198 * the "transaction active" state we maintain ensures that there can
199 * only be one active transaction at a time.
200 */
201
202 buf_len = fcopy_transaction.recv_len;
203 channel = fcopy_transaction.recv_channel;
204 req_id = fcopy_transaction.recv_req_id;
205
206 icmsghdr = (struct icmsg_hdr *)
207 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
208
209 if (channel->onchannel_callback == NULL)
210 /*
211 * We have raced with util driver being unloaded;
212 * silently return.
213 */
214 return;
215
216 icmsghdr->status = error;
217 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
218 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
219 VM_PKT_DATA_INBAND, 0);
220 }
221
hv_fcopy_onchannelcallback(void * context)222 void hv_fcopy_onchannelcallback(void *context)
223 {
224 struct vmbus_channel *channel = context;
225 u32 recvlen;
226 u64 requestid;
227 struct hv_fcopy_hdr *fcopy_msg;
228 struct icmsg_hdr *icmsghdr;
229 struct icmsg_negotiate *negop = NULL;
230 int util_fw_version;
231 int fcopy_srv_version;
232
233 if (fcopy_transaction.state > HVUTIL_READY)
234 return;
235
236 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
237 &requestid);
238 if (recvlen <= 0)
239 return;
240
241 icmsghdr = (struct icmsg_hdr *)&recv_buffer[
242 sizeof(struct vmbuspipe_hdr)];
243 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
244 util_fw_version = UTIL_FW_VERSION;
245 fcopy_srv_version = WIN8_SRV_VERSION;
246 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
247 util_fw_version, fcopy_srv_version);
248 } else {
249 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
250 sizeof(struct vmbuspipe_hdr) +
251 sizeof(struct icmsg_hdr)];
252
253 /*
254 * Stash away this global state for completing the
255 * transaction; note transactions are serialized.
256 */
257
258 fcopy_transaction.recv_len = recvlen;
259 fcopy_transaction.recv_req_id = requestid;
260 fcopy_transaction.fcopy_msg = fcopy_msg;
261
262 if (fcopy_transaction.state < HVUTIL_READY) {
263 /* Userspace is not registered yet */
264 fcopy_respond_to_host(HV_E_FAIL);
265 return;
266 }
267 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
268
269 /*
270 * Send the information to the user-level daemon.
271 */
272 schedule_work(&fcopy_send_work);
273 schedule_delayed_work(&fcopy_timeout_work,
274 HV_UTIL_TIMEOUT * HZ);
275 return;
276 }
277 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
278 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
279 VM_PKT_DATA_INBAND, 0);
280 }
281
282 /* Callback when data is received from userspace */
fcopy_on_msg(void * msg,int len)283 static int fcopy_on_msg(void *msg, int len)
284 {
285 int *val = (int *)msg;
286
287 if (len != sizeof(int))
288 return -EINVAL;
289
290 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
291 return fcopy_handle_handshake(*val);
292
293 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
294 return -EINVAL;
295
296 /*
297 * Complete the transaction by forwarding the result
298 * to the host. But first, cancel the timeout.
299 */
300 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
301 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
302 fcopy_respond_to_host(*val);
303 hv_poll_channel(fcopy_transaction.recv_channel,
304 fcopy_poll_wrapper);
305 }
306
307 return 0;
308 }
309
fcopy_on_reset(void)310 static void fcopy_on_reset(void)
311 {
312 /*
313 * The daemon has exited; reset the state.
314 */
315 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
316
317 if (cancel_delayed_work_sync(&fcopy_timeout_work))
318 fcopy_respond_to_host(HV_E_FAIL);
319 complete(&release_event);
320 }
321
hv_fcopy_init(struct hv_util_service * srv)322 int hv_fcopy_init(struct hv_util_service *srv)
323 {
324 recv_buffer = srv->recv_buffer;
325 fcopy_transaction.recv_channel = srv->channel;
326
327 init_completion(&release_event);
328 /*
329 * When this driver loads, the user level daemon that
330 * processes the host requests may not yet be running.
331 * Defer processing channel callbacks until the daemon
332 * has registered.
333 */
334 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
335
336 hvt = hvutil_transport_init(fcopy_devname, 0, 0,
337 fcopy_on_msg, fcopy_on_reset);
338 if (!hvt)
339 return -EFAULT;
340
341 return 0;
342 }
343
hv_fcopy_deinit(void)344 void hv_fcopy_deinit(void)
345 {
346 fcopy_transaction.state = HVUTIL_DEVICE_DYING;
347 cancel_delayed_work_sync(&fcopy_timeout_work);
348 hvutil_transport_destroy(hvt);
349 wait_for_completion(&release_event);
350 }
351