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#define FCOPY_VER_COUNT 1
35static const int fcopy_versions[] = {
36 WIN8_SRV_VERSION
37};
38
39#define FW_VER_COUNT 1
40static const int fw_versions[] = {
41 UTIL_FW_VERSION
42};
43
44/*
45 * Global state maintained for transaction that is being processed.
46 * For a class of integration services, including the "file copy service",
47 * the specified protocol is a "request/response" protocol which means that
48 * there can only be single outstanding transaction from the host at any
49 * given point in time. We use this to simplify memory management in this
50 * driver - we cache and process only one message at a time.
51 *
52 * While the request/response protocol is guaranteed by the host, we further
53 * ensure this by serializing packet processing in this driver - we do not
54 * read additional packets from the VMBUs until the current packet is fully
55 * handled.
56 */
57
58static struct {
59 int state; /* hvutil_device_state */
60 int recv_len; /* number of bytes received. */
61 struct hv_fcopy_hdr *fcopy_msg; /* current message */
62 struct vmbus_channel *recv_channel; /* chn we got the request */
63 u64 recv_req_id; /* request ID. */
64} fcopy_transaction;
65
66static void fcopy_respond_to_host(int error);
67static void fcopy_send_data(struct work_struct *dummy);
68static void fcopy_timeout_func(struct work_struct *dummy);
69static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
70static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
71static const char fcopy_devname[] = "vmbus/hv_fcopy";
72static u8 *recv_buffer;
73static struct hvutil_transport *hvt;
74/*
75 * This state maintains the version number registered by the daemon.
76 */
77static int dm_reg_value;
78
79static void fcopy_poll_wrapper(void *channel)
80{
81 /* Transaction is finished, reset the state here to avoid races. */
82 fcopy_transaction.state = HVUTIL_READY;
83 hv_fcopy_onchannelcallback(channel);
84}
85
86static void fcopy_timeout_func(struct work_struct *dummy)
87{
88 /*
89 * If the timer fires, the user-mode component has not responded;
90 * process the pending transaction.
91 */
92 fcopy_respond_to_host(HV_E_FAIL);
93 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
94}
95
96static void fcopy_register_done(void)
97{
98 pr_debug("FCP: userspace daemon registered\n");
99 hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
100}
101
102static int fcopy_handle_handshake(u32 version)
103{
104 u32 our_ver = FCOPY_CURRENT_VERSION;
105
106 switch (version) {
107 case FCOPY_VERSION_0:
108 /* Daemon doesn't expect us to reply */
109 dm_reg_value = version;
110 break;
111 case FCOPY_VERSION_1:
112 /* Daemon expects us to reply with our own version */
113 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
114 fcopy_register_done))
115 return -EFAULT;
116 dm_reg_value = version;
117 break;
118 default:
119 /*
120 * For now we will fail the registration.
121 * If and when we have multiple versions to
122 * deal with, we will be backward compatible.
123 * We will add this code when needed.
124 */
125 return -EINVAL;
126 }
127 pr_debug("FCP: userspace daemon ver. %d connected\n", version);
128 return 0;
129}
130
131static void fcopy_send_data(struct work_struct *dummy)
132{
133 struct hv_start_fcopy *smsg_out = NULL;
134 int operation = fcopy_transaction.fcopy_msg->operation;
135 struct hv_start_fcopy *smsg_in;
136 void *out_src;
137 int rc, out_len;
138
139 /*
140 * The strings sent from the host are encoded in
141 * in utf16; convert it to utf8 strings.
142 * The host assures us that the utf16 strings will not exceed
143 * the max lengths specified. We will however, reserve room
144 * for the string terminating character - in the utf16s_utf8s()
145 * function we limit the size of the buffer where the converted
146 * string is placed to W_MAX_PATH -1 to guarantee
147 * that the strings can be properly terminated!
148 */
149
150 switch (operation) {
151 case START_FILE_COPY:
152 out_len = sizeof(struct hv_start_fcopy);
153 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
154 if (!smsg_out)
155 return;
156
157 smsg_out->hdr.operation = operation;
158 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
159
160 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
161 UTF16_LITTLE_ENDIAN,
162 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
163
164 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
165 UTF16_LITTLE_ENDIAN,
166 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
167
168 smsg_out->copy_flags = smsg_in->copy_flags;
169 smsg_out->file_size = smsg_in->file_size;
170 out_src = smsg_out;
171 break;
172
173 case WRITE_TO_FILE:
174 out_src = fcopy_transaction.fcopy_msg;
175 out_len = sizeof(struct hv_do_fcopy);
176 break;
177 default:
178 out_src = fcopy_transaction.fcopy_msg;
179 out_len = fcopy_transaction.recv_len;
180 break;
181 }
182
183 fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
184 rc = hvutil_transport_send(hvt, out_src, out_len, NULL);
185 if (rc) {
186 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
187 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
188 fcopy_respond_to_host(HV_E_FAIL);
189 fcopy_transaction.state = HVUTIL_READY;
190 }
191 }
192 kfree(smsg_out);
193}
194
195/*
196 * Send a response back to the host.
197 */
198
199static void
200fcopy_respond_to_host(int error)
201{
202 struct icmsg_hdr *icmsghdr;
203 u32 buf_len;
204 struct vmbus_channel *channel;
205 u64 req_id;
206
207 /*
208 * Copy the global state for completing the transaction. Note that
209 * only one transaction can be active at a time. This is guaranteed
210 * by the file copy protocol implemented by the host. Furthermore,
211 * the "transaction active" state we maintain ensures that there can
212 * only be one active transaction at a time.
213 */
214
215 buf_len = fcopy_transaction.recv_len;
216 channel = fcopy_transaction.recv_channel;
217 req_id = fcopy_transaction.recv_req_id;
218
219 icmsghdr = (struct icmsg_hdr *)
220 &recv_buffer[sizeof(struct vmbuspipe_hdr)];
221
222 if (channel->onchannel_callback == NULL)
223 /*
224 * We have raced with util driver being unloaded;
225 * silently return.
226 */
227 return;
228
229 icmsghdr->status = error;
230 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
231 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
232 VM_PKT_DATA_INBAND, 0);
233}
234
235void hv_fcopy_onchannelcallback(void *context)
236{
237 struct vmbus_channel *channel = context;
238 u32 recvlen;
239 u64 requestid;
240 struct hv_fcopy_hdr *fcopy_msg;
241 struct icmsg_hdr *icmsghdr;
242 int fcopy_srv_version;
243
244 if (fcopy_transaction.state > HVUTIL_READY)
245 return;
246
247 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
248 &requestid);
249 if (recvlen <= 0)
250 return;
251
252 icmsghdr = (struct icmsg_hdr *)&recv_buffer[
253 sizeof(struct vmbuspipe_hdr)];
254 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
255 if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer,
256 fw_versions, FW_VER_COUNT,
257 fcopy_versions, FCOPY_VER_COUNT,
258 NULL, &fcopy_srv_version)) {
259
260 pr_info("FCopy IC version %d.%d\n",
261 fcopy_srv_version >> 16,
262 fcopy_srv_version & 0xFFFF);
263 }
264 } else {
265 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
266 sizeof(struct vmbuspipe_hdr) +
267 sizeof(struct icmsg_hdr)];
268
269 /*
270 * Stash away this global state for completing the
271 * transaction; note transactions are serialized.
272 */
273
274 fcopy_transaction.recv_len = recvlen;
275 fcopy_transaction.recv_req_id = requestid;
276 fcopy_transaction.fcopy_msg = fcopy_msg;
277
278 if (fcopy_transaction.state < HVUTIL_READY) {
279 /* Userspace is not registered yet */
280 fcopy_respond_to_host(HV_E_FAIL);
281 return;
282 }
283 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
284
285 /*
286 * Send the information to the user-level daemon.
287 */
288 schedule_work(&fcopy_send_work);
289 schedule_delayed_work(&fcopy_timeout_work,
290 HV_UTIL_TIMEOUT * HZ);
291 return;
292 }
293 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
294 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
295 VM_PKT_DATA_INBAND, 0);
296}
297
298/* Callback when data is received from userspace */
299static int fcopy_on_msg(void *msg, int len)
300{
301 int *val = (int *)msg;
302
303 if (len != sizeof(int))
304 return -EINVAL;
305
306 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
307 return fcopy_handle_handshake(*val);
308
309 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
310 return -EINVAL;
311
312 /*
313 * Complete the transaction by forwarding the result
314 * to the host. But first, cancel the timeout.
315 */
316 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
317 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
318 fcopy_respond_to_host(*val);
319 hv_poll_channel(fcopy_transaction.recv_channel,
320 fcopy_poll_wrapper);
321 }
322
323 return 0;
324}
325
326static void fcopy_on_reset(void)
327{
328 /*
329 * The daemon has exited; reset the state.
330 */
331 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
332
333 if (cancel_delayed_work_sync(&fcopy_timeout_work))
334 fcopy_respond_to_host(HV_E_FAIL);
335}
336
337int hv_fcopy_init(struct hv_util_service *srv)
338{
339 recv_buffer = srv->recv_buffer;
340 fcopy_transaction.recv_channel = srv->channel;
341
342 /*
343 * When this driver loads, the user level daemon that
344 * processes the host requests may not yet be running.
345 * Defer processing channel callbacks until the daemon
346 * has registered.
347 */
348 fcopy_transaction.state = HVUTIL_DEVICE_INIT;
349
350 hvt = hvutil_transport_init(fcopy_devname, 0, 0,
351 fcopy_on_msg, fcopy_on_reset);
352 if (!hvt)
353 return -EFAULT;
354
355 return 0;
356}
357
358void hv_fcopy_deinit(void)
359{
360 fcopy_transaction.state = HVUTIL_DEVICE_DYING;
361 cancel_delayed_work_sync(&fcopy_timeout_work);
362 hvutil_transport_destroy(hvt);
363}
364