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 void *fcopy_context; /* for the channel callback */ 55 } fcopy_transaction; 56 57 static void fcopy_respond_to_host(int error); 58 static void fcopy_send_data(struct work_struct *dummy); 59 static void fcopy_timeout_func(struct work_struct *dummy); 60 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func); 61 static DECLARE_WORK(fcopy_send_work, fcopy_send_data); 62 static const char fcopy_devname[] = "vmbus/hv_fcopy"; 63 static u8 *recv_buffer; 64 static struct hvutil_transport *hvt; 65 /* 66 * This state maintains the version number registered by the daemon. 67 */ 68 static int dm_reg_value; 69 70 static void fcopy_timeout_func(struct work_struct *dummy) 71 { 72 /* 73 * If the timer fires, the user-mode component has not responded; 74 * process the pending transaction. 75 */ 76 fcopy_respond_to_host(HV_E_FAIL); 77 78 /* Transaction is finished, reset the state. */ 79 if (fcopy_transaction.state > HVUTIL_READY) 80 fcopy_transaction.state = HVUTIL_READY; 81 82 hv_poll_channel(fcopy_transaction.fcopy_context, 83 hv_fcopy_onchannelcallback); 84 } 85 86 static 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 fcopy_transaction.state = HVUTIL_READY; 112 hv_poll_channel(fcopy_transaction.fcopy_context, 113 hv_fcopy_onchannelcallback); 114 return 0; 115 } 116 117 static void fcopy_send_data(struct work_struct *dummy) 118 { 119 struct hv_start_fcopy *smsg_out = NULL; 120 int operation = fcopy_transaction.fcopy_msg->operation; 121 struct hv_start_fcopy *smsg_in; 122 void *out_src; 123 int rc, out_len; 124 125 /* 126 * The strings sent from the host are encoded in 127 * in utf16; convert it to utf8 strings. 128 * The host assures us that the utf16 strings will not exceed 129 * the max lengths specified. We will however, reserve room 130 * for the string terminating character - in the utf16s_utf8s() 131 * function we limit the size of the buffer where the converted 132 * string is placed to W_MAX_PATH -1 to guarantee 133 * that the strings can be properly terminated! 134 */ 135 136 switch (operation) { 137 case START_FILE_COPY: 138 out_len = sizeof(struct hv_start_fcopy); 139 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL); 140 if (!smsg_out) 141 return; 142 143 smsg_out->hdr.operation = operation; 144 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg; 145 146 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH, 147 UTF16_LITTLE_ENDIAN, 148 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1); 149 150 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH, 151 UTF16_LITTLE_ENDIAN, 152 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1); 153 154 smsg_out->copy_flags = smsg_in->copy_flags; 155 smsg_out->file_size = smsg_in->file_size; 156 out_src = smsg_out; 157 break; 158 159 default: 160 out_src = fcopy_transaction.fcopy_msg; 161 out_len = fcopy_transaction.recv_len; 162 break; 163 } 164 165 fcopy_transaction.state = HVUTIL_USERSPACE_REQ; 166 rc = hvutil_transport_send(hvt, out_src, out_len); 167 if (rc) { 168 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); 169 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 170 fcopy_respond_to_host(HV_E_FAIL); 171 fcopy_transaction.state = HVUTIL_READY; 172 } 173 } 174 kfree(smsg_out); 175 176 return; 177 } 178 179 /* 180 * Send a response back to the host. 181 */ 182 183 static void 184 fcopy_respond_to_host(int error) 185 { 186 struct icmsg_hdr *icmsghdr; 187 u32 buf_len; 188 struct vmbus_channel *channel; 189 u64 req_id; 190 191 /* 192 * Copy the global state for completing the transaction. Note that 193 * only one transaction can be active at a time. This is guaranteed 194 * by the file copy protocol implemented by the host. Furthermore, 195 * the "transaction active" state we maintain ensures that there can 196 * only be one active transaction at a time. 197 */ 198 199 buf_len = fcopy_transaction.recv_len; 200 channel = fcopy_transaction.recv_channel; 201 req_id = fcopy_transaction.recv_req_id; 202 203 icmsghdr = (struct icmsg_hdr *) 204 &recv_buffer[sizeof(struct vmbuspipe_hdr)]; 205 206 if (channel->onchannel_callback == NULL) 207 /* 208 * We have raced with util driver being unloaded; 209 * silently return. 210 */ 211 return; 212 213 icmsghdr->status = error; 214 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 215 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, 216 VM_PKT_DATA_INBAND, 0); 217 } 218 219 void hv_fcopy_onchannelcallback(void *context) 220 { 221 struct vmbus_channel *channel = context; 222 u32 recvlen; 223 u64 requestid; 224 struct hv_fcopy_hdr *fcopy_msg; 225 struct icmsg_hdr *icmsghdr; 226 struct icmsg_negotiate *negop = NULL; 227 int util_fw_version; 228 int fcopy_srv_version; 229 230 if (fcopy_transaction.state > HVUTIL_READY) { 231 /* 232 * We will defer processing this callback once 233 * the current transaction is complete. 234 */ 235 fcopy_transaction.fcopy_context = context; 236 return; 237 } 238 fcopy_transaction.fcopy_context = NULL; 239 240 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, 241 &requestid); 242 if (recvlen <= 0) 243 return; 244 245 icmsghdr = (struct icmsg_hdr *)&recv_buffer[ 246 sizeof(struct vmbuspipe_hdr)]; 247 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) { 248 util_fw_version = UTIL_FW_VERSION; 249 fcopy_srv_version = WIN8_SRV_VERSION; 250 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer, 251 util_fw_version, fcopy_srv_version); 252 } else { 253 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ 254 sizeof(struct vmbuspipe_hdr) + 255 sizeof(struct icmsg_hdr)]; 256 257 /* 258 * Stash away this global state for completing the 259 * transaction; note transactions are serialized. 260 */ 261 262 fcopy_transaction.recv_len = recvlen; 263 fcopy_transaction.recv_channel = channel; 264 fcopy_transaction.recv_req_id = requestid; 265 fcopy_transaction.fcopy_msg = fcopy_msg; 266 267 if (fcopy_transaction.state < HVUTIL_READY) { 268 /* Userspace is not registered yet */ 269 fcopy_respond_to_host(HV_E_FAIL); 270 return; 271 } 272 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED; 273 274 /* 275 * Send the information to the user-level daemon. 276 */ 277 schedule_work(&fcopy_send_work); 278 schedule_delayed_work(&fcopy_timeout_work, 5*HZ); 279 return; 280 } 281 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 282 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, 283 VM_PKT_DATA_INBAND, 0); 284 } 285 286 /* Callback when data is received from userspace */ 287 static int fcopy_on_msg(void *msg, int len) 288 { 289 int *val = (int *)msg; 290 291 if (len != sizeof(int)) 292 return -EINVAL; 293 294 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) 295 return fcopy_handle_handshake(*val); 296 297 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) 298 return -EINVAL; 299 300 /* 301 * Complete the transaction by forwarding the result 302 * to the host. But first, cancel the timeout. 303 */ 304 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 305 fcopy_transaction.state = HVUTIL_USERSPACE_RECV; 306 fcopy_respond_to_host(*val); 307 fcopy_transaction.state = HVUTIL_READY; 308 hv_poll_channel(fcopy_transaction.fcopy_context, 309 hv_fcopy_onchannelcallback); 310 } 311 312 return 0; 313 } 314 315 static void fcopy_on_reset(void) 316 { 317 /* 318 * The daemon has exited; reset the state. 319 */ 320 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 321 322 if (cancel_delayed_work_sync(&fcopy_timeout_work)) 323 fcopy_respond_to_host(HV_E_FAIL); 324 } 325 326 int hv_fcopy_init(struct hv_util_service *srv) 327 { 328 recv_buffer = srv->recv_buffer; 329 330 /* 331 * When this driver loads, the user level daemon that 332 * processes the host requests may not yet be running. 333 * Defer processing channel callbacks until the daemon 334 * has registered. 335 */ 336 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 337 338 hvt = hvutil_transport_init(fcopy_devname, 0, 0, 339 fcopy_on_msg, fcopy_on_reset); 340 if (!hvt) 341 return -EFAULT; 342 343 return 0; 344 } 345 346 void hv_fcopy_deinit(void) 347 { 348 fcopy_transaction.state = HVUTIL_DEVICE_DYING; 349 cancel_delayed_work_sync(&fcopy_timeout_work); 350 hvutil_transport_destroy(hvt); 351 } 352