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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * An implementation of file copy service.
4 *
5 * Copyright (C) 2014, Microsoft, Inc.
6 *
7 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/nls.h>
13#include <linux/workqueue.h>
14#include <linux/hyperv.h>
15#include <linux/sched.h>
16
17#include "hyperv_vmbus.h"
18#include "hv_utils_transport.h"
19
20#define WIN8_SRV_MAJOR 1
21#define WIN8_SRV_MINOR 1
22#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
23
24#define FCOPY_VER_COUNT 1
25static const int fcopy_versions[] = {
26 WIN8_SRV_VERSION
27};
28
29#define FW_VER_COUNT 1
30static const int fw_versions[] = {
31 UTIL_FW_VERSION
32};
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 void fcopy_register_done(void)
87{
88 pr_debug("FCP: userspace daemon registered\n");
89 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
90}
91
92static int fcopy_handle_handshake(u32 version)
93{
94 u32 our_ver = FCOPY_CURRENT_VERSION;
95
96 switch (version) {
97 case FCOPY_VERSION_0:
98 /* Daemon doesn't expect us to reply */
99 dm_reg_value = version;
100 break;
101 case FCOPY_VERSION_1:
102 /* Daemon expects us to reply with our own version */
103 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
104 fcopy_register_done))
105 return -EFAULT;
106 dm_reg_value = version;
107 break;
108 default:
109 /*
110 * For now we will fail the registration.
111 * If and when we have multiple versions to
112 * deal with, we will be backward compatible.
113 * We will add this code when needed.
114 */
115 return -EINVAL;
116 }
117 pr_debug("FCP: userspace daemon ver. %d connected\n", version);
118 return 0;
119}
120
121static void fcopy_send_data(struct work_struct *dummy)
122{
123 struct hv_start_fcopy *smsg_out = NULL;
124 int operation = fcopy_transaction.fcopy_msg->operation;
125 struct hv_start_fcopy *smsg_in;
126 void *out_src;
127 int rc, out_len;
128
129 /*
130 * The strings sent from the host are encoded in
131 * in utf16; convert it to utf8 strings.
132 * The host assures us that the utf16 strings will not exceed
133 * the max lengths specified. We will however, reserve room
134 * for the string terminating character - in the utf16s_utf8s()
135 * function we limit the size of the buffer where the converted
136 * string is placed to W_MAX_PATH -1 to guarantee
137 * that the strings can be properly terminated!
138 */
139
140 switch (operation) {
141 case START_FILE_COPY:
142 out_len = sizeof(struct hv_start_fcopy);
143 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
144 if (!smsg_out)
145 return;
146
147 smsg_out->hdr.operation = operation;
148 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
149
150 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
151 UTF16_LITTLE_ENDIAN,
152 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
153
154 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
155 UTF16_LITTLE_ENDIAN,
156 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
157
158 smsg_out->copy_flags = smsg_in->copy_flags;
159 smsg_out->file_size = smsg_in->file_size;
160 out_src = smsg_out;
161 break;
162
163 case WRITE_TO_FILE:
164 out_src = fcopy_transaction.fcopy_msg;
165 out_len = sizeof(struct hv_do_fcopy);
166 break;
167 default:
168 out_src = fcopy_transaction.fcopy_msg;
169 out_len = fcopy_transaction.recv_len;
170 break;
171 }
172
173 fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
174 rc = hvutil_transport_send(hvt, out_src, out_len, NULL);
175 if (rc) {
176 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
177 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
178 fcopy_respond_to_host(HV_E_FAIL);
179 fcopy_transaction.state = HVUTIL_READY;
180 }
181 }
182 kfree(smsg_out);
183}
184
185/*
186 * Send a response back to the host.
187 */
188
189static void
190fcopy_respond_to_host(int error)
191{
192 struct icmsg_hdr *icmsghdr;
193 u32 buf_len;
194 struct vmbus_channel *channel;
195 u64 req_id;
196
197 /*
198 * Copy the global state for completing the transaction. Note that
199 * only one transaction can be active at a time. This is guaranteed
200 * by the file copy protocol implemented by the host. Furthermore,
201 * the "transaction active" state we maintain ensures that there can
202 * only be one active transaction at a time.
203 */
204
205 buf_len = fcopy_transaction.recv_len;
206 channel = fcopy_transaction.recv_channel;
207 req_id = fcopy_transaction.recv_req_id;
208
209 icmsghdr = (struct icmsg_hdr *)
210 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
211
212 if (channel->onchannel_callback == NULL)
213 /*
214 * We have raced with util driver being unloaded;
215 * silently return.
216 */
217 return;
218
219 icmsghdr->status = error;
220 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
221 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
222 VM_PKT_DATA_INBAND, 0);
223}
224
225void hv_fcopy_onchannelcallback(void *context)
226{
227 struct vmbus_channel *channel = context;
228 u32 recvlen;
229 u64 requestid;
230 struct hv_fcopy_hdr *fcopy_msg;
231 struct icmsg_hdr *icmsghdr;
232 int fcopy_srv_version;
233
234 if (fcopy_transaction.state > HVUTIL_READY)
235 return;
236
237 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
238 &requestid);
239 if (recvlen <= 0)
240 return;
241
242 icmsghdr = (struct icmsg_hdr *)&recv_buffer[
243 sizeof(struct vmbuspipe_hdr)];
244 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
245 if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer,
246 fw_versions, FW_VER_COUNT,
247 fcopy_versions, FCOPY_VER_COUNT,
248 NULL, &fcopy_srv_version)) {
249
250 pr_info("FCopy IC version %d.%d\n",
251 fcopy_srv_version >> 16,
252 fcopy_srv_version & 0xFFFF);
253 }
254 } else {
255 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
256 sizeof(struct vmbuspipe_hdr) +
257 sizeof(struct icmsg_hdr)];
258
259 /*
260 * Stash away this global state for completing the
261 * transaction; note transactions are serialized.
262 */
263
264 fcopy_transaction.recv_len = recvlen;
265 fcopy_transaction.recv_req_id = requestid;
266 fcopy_transaction.fcopy_msg = fcopy_msg;
267
268 if (fcopy_transaction.state < HVUTIL_READY) {
269 /* Userspace is not registered yet */
270 fcopy_respond_to_host(HV_E_FAIL);
271 return;
272 }
273 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
274
275 /*
276 * Send the information to the user-level daemon.
277 */
278 schedule_work(&fcopy_send_work);
279 schedule_delayed_work(&fcopy_timeout_work,
280 HV_UTIL_TIMEOUT * HZ);
281 return;
282 }
283 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
284 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
285 VM_PKT_DATA_INBAND, 0);
286}
287
288/* Callback when data is received from userspace */
289static int fcopy_on_msg(void *msg, int len)
290{
291 int *val = (int *)msg;
292
293 if (len != sizeof(int))
294 return -EINVAL;
295
296 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
297 return fcopy_handle_handshake(*val);
298
299 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
300 return -EINVAL;
301
302 /*
303 * Complete the transaction by forwarding the result
304 * to the host. But first, cancel the timeout.
305 */
306 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
307 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
308 fcopy_respond_to_host(*val);
309 hv_poll_channel(fcopy_transaction.recv_channel,
310 fcopy_poll_wrapper);
311 }
312
313 return 0;
314}
315
316static void fcopy_on_reset(void)
317{
318 /*
319 * The daemon has exited; reset the state.
320 */
321 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
322
323 if (cancel_delayed_work_sync(&fcopy_timeout_work))
324 fcopy_respond_to_host(HV_E_FAIL);
325}
326
327int hv_fcopy_init(struct hv_util_service *srv)
328{
329 recv_buffer = srv->recv_buffer;
330 fcopy_transaction.recv_channel = srv->channel;
331
332 /*
333 * When this driver loads, the user level daemon that
334 * processes the host requests may not yet be running.
335 * Defer processing channel callbacks until the daemon
336 * has registered.
337 */
338 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
339
340 hvt = hvutil_transport_init(fcopy_devname, 0, 0,
341 fcopy_on_msg, fcopy_on_reset);
342 if (!hvt)
343 return -EFAULT;
344
345 return 0;
346}
347
348void hv_fcopy_deinit(void)
349{
350 fcopy_transaction.state = HVUTIL_DEVICE_DYING;
351 cancel_delayed_work_sync(&fcopy_timeout_work);
352 hvutil_transport_destroy(hvt);
353}