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 35 static const int fcopy_versions[] = { 36 WIN8_SRV_VERSION 37 }; 38 39 #define FW_VER_COUNT 1 40 static 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 58 static 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 66 static void fcopy_respond_to_host(int error); 67 static void fcopy_send_data(struct work_struct *dummy); 68 static void fcopy_timeout_func(struct work_struct *dummy); 69 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func); 70 static DECLARE_WORK(fcopy_send_work, fcopy_send_data); 71 static const char fcopy_devname[] = "vmbus/hv_fcopy"; 72 static u8 *recv_buffer; 73 static struct hvutil_transport *hvt; 74 /* 75 * This state maintains the version number registered by the daemon. 76 */ 77 static int dm_reg_value; 78 79 static 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 86 static 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 96 static 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 } 101 102 static 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 } 130 131 static 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 default: 174 out_src = fcopy_transaction.fcopy_msg; 175 out_len = fcopy_transaction.recv_len; 176 break; 177 } 178 179 fcopy_transaction.state = HVUTIL_USERSPACE_REQ; 180 rc = hvutil_transport_send(hvt, out_src, out_len, NULL); 181 if (rc) { 182 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); 183 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 184 fcopy_respond_to_host(HV_E_FAIL); 185 fcopy_transaction.state = HVUTIL_READY; 186 } 187 } 188 kfree(smsg_out); 189 } 190 191 /* 192 * Send a response back to the host. 193 */ 194 195 static void 196 fcopy_respond_to_host(int error) 197 { 198 struct icmsg_hdr *icmsghdr; 199 u32 buf_len; 200 struct vmbus_channel *channel; 201 u64 req_id; 202 203 /* 204 * Copy the global state for completing the transaction. Note that 205 * only one transaction can be active at a time. This is guaranteed 206 * by the file copy protocol implemented by the host. Furthermore, 207 * the "transaction active" state we maintain ensures that there can 208 * only be one active transaction at a time. 209 */ 210 211 buf_len = fcopy_transaction.recv_len; 212 channel = fcopy_transaction.recv_channel; 213 req_id = fcopy_transaction.recv_req_id; 214 215 icmsghdr = (struct icmsg_hdr *) 216 &recv_buffer[sizeof(struct vmbuspipe_hdr)]; 217 218 if (channel->onchannel_callback == NULL) 219 /* 220 * We have raced with util driver being unloaded; 221 * silently return. 222 */ 223 return; 224 225 icmsghdr->status = error; 226 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 227 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, 228 VM_PKT_DATA_INBAND, 0); 229 } 230 231 void hv_fcopy_onchannelcallback(void *context) 232 { 233 struct vmbus_channel *channel = context; 234 u32 recvlen; 235 u64 requestid; 236 struct hv_fcopy_hdr *fcopy_msg; 237 struct icmsg_hdr *icmsghdr; 238 int fcopy_srv_version; 239 240 if (fcopy_transaction.state > HVUTIL_READY) 241 return; 242 243 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, 244 &requestid); 245 if (recvlen <= 0) 246 return; 247 248 icmsghdr = (struct icmsg_hdr *)&recv_buffer[ 249 sizeof(struct vmbuspipe_hdr)]; 250 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) { 251 if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer, 252 fw_versions, FW_VER_COUNT, 253 fcopy_versions, FCOPY_VER_COUNT, 254 NULL, &fcopy_srv_version)) { 255 256 pr_info("FCopy IC version %d.%d\n", 257 fcopy_srv_version >> 16, 258 fcopy_srv_version & 0xFFFF); 259 } 260 } else { 261 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ 262 sizeof(struct vmbuspipe_hdr) + 263 sizeof(struct icmsg_hdr)]; 264 265 /* 266 * Stash away this global state for completing the 267 * transaction; note transactions are serialized. 268 */ 269 270 fcopy_transaction.recv_len = recvlen; 271 fcopy_transaction.recv_req_id = requestid; 272 fcopy_transaction.fcopy_msg = fcopy_msg; 273 274 if (fcopy_transaction.state < HVUTIL_READY) { 275 /* Userspace is not registered yet */ 276 fcopy_respond_to_host(HV_E_FAIL); 277 return; 278 } 279 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED; 280 281 /* 282 * Send the information to the user-level daemon. 283 */ 284 schedule_work(&fcopy_send_work); 285 schedule_delayed_work(&fcopy_timeout_work, 286 HV_UTIL_TIMEOUT * HZ); 287 return; 288 } 289 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 290 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, 291 VM_PKT_DATA_INBAND, 0); 292 } 293 294 /* Callback when data is received from userspace */ 295 static int fcopy_on_msg(void *msg, int len) 296 { 297 int *val = (int *)msg; 298 299 if (len != sizeof(int)) 300 return -EINVAL; 301 302 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) 303 return fcopy_handle_handshake(*val); 304 305 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) 306 return -EINVAL; 307 308 /* 309 * Complete the transaction by forwarding the result 310 * to the host. But first, cancel the timeout. 311 */ 312 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 313 fcopy_transaction.state = HVUTIL_USERSPACE_RECV; 314 fcopy_respond_to_host(*val); 315 hv_poll_channel(fcopy_transaction.recv_channel, 316 fcopy_poll_wrapper); 317 } 318 319 return 0; 320 } 321 322 static void fcopy_on_reset(void) 323 { 324 /* 325 * The daemon has exited; reset the state. 326 */ 327 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 328 329 if (cancel_delayed_work_sync(&fcopy_timeout_work)) 330 fcopy_respond_to_host(HV_E_FAIL); 331 } 332 333 int hv_fcopy_init(struct hv_util_service *srv) 334 { 335 recv_buffer = srv->recv_buffer; 336 fcopy_transaction.recv_channel = srv->channel; 337 338 /* 339 * When this driver loads, the user level daemon that 340 * processes the host requests may not yet be running. 341 * Defer processing channel callbacks until the daemon 342 * has registered. 343 */ 344 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 345 346 hvt = hvutil_transport_init(fcopy_devname, 0, 0, 347 fcopy_on_msg, fcopy_on_reset); 348 if (!hvt) 349 return -EFAULT; 350 351 return 0; 352 } 353 354 void hv_fcopy_deinit(void) 355 { 356 fcopy_transaction.state = HVUTIL_DEVICE_DYING; 357 cancel_delayed_work_sync(&fcopy_timeout_work); 358 hvutil_transport_destroy(hvt); 359 } 360