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; 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 memset(&smsg_out, 0, out_len); 140 smsg_out.hdr.operation = operation; 141 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg; 142 143 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH, 144 UTF16_LITTLE_ENDIAN, 145 (__u8 *)&smsg_out.file_name, W_MAX_PATH - 1); 146 147 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH, 148 UTF16_LITTLE_ENDIAN, 149 (__u8 *)&smsg_out.path_name, W_MAX_PATH - 1); 150 151 smsg_out.copy_flags = smsg_in->copy_flags; 152 smsg_out.file_size = smsg_in->file_size; 153 out_src = &smsg_out; 154 break; 155 156 default: 157 out_src = fcopy_transaction.fcopy_msg; 158 out_len = fcopy_transaction.recv_len; 159 break; 160 } 161 162 fcopy_transaction.state = HVUTIL_USERSPACE_REQ; 163 rc = hvutil_transport_send(hvt, out_src, out_len); 164 if (rc) { 165 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); 166 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 167 fcopy_respond_to_host(HV_E_FAIL); 168 fcopy_transaction.state = HVUTIL_READY; 169 } 170 } 171 return; 172 } 173 174 /* 175 * Send a response back to the host. 176 */ 177 178 static void 179 fcopy_respond_to_host(int error) 180 { 181 struct icmsg_hdr *icmsghdr; 182 u32 buf_len; 183 struct vmbus_channel *channel; 184 u64 req_id; 185 186 /* 187 * Copy the global state for completing the transaction. Note that 188 * only one transaction can be active at a time. This is guaranteed 189 * by the file copy protocol implemented by the host. Furthermore, 190 * the "transaction active" state we maintain ensures that there can 191 * only be one active transaction at a time. 192 */ 193 194 buf_len = fcopy_transaction.recv_len; 195 channel = fcopy_transaction.recv_channel; 196 req_id = fcopy_transaction.recv_req_id; 197 198 icmsghdr = (struct icmsg_hdr *) 199 &recv_buffer[sizeof(struct vmbuspipe_hdr)]; 200 201 if (channel->onchannel_callback == NULL) 202 /* 203 * We have raced with util driver being unloaded; 204 * silently return. 205 */ 206 return; 207 208 icmsghdr->status = error; 209 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 210 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, 211 VM_PKT_DATA_INBAND, 0); 212 } 213 214 void hv_fcopy_onchannelcallback(void *context) 215 { 216 struct vmbus_channel *channel = context; 217 u32 recvlen; 218 u64 requestid; 219 struct hv_fcopy_hdr *fcopy_msg; 220 struct icmsg_hdr *icmsghdr; 221 struct icmsg_negotiate *negop = NULL; 222 int util_fw_version; 223 int fcopy_srv_version; 224 225 if (fcopy_transaction.state > HVUTIL_READY) { 226 /* 227 * We will defer processing this callback once 228 * the current transaction is complete. 229 */ 230 fcopy_transaction.fcopy_context = context; 231 return; 232 } 233 fcopy_transaction.fcopy_context = NULL; 234 235 vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, 236 &requestid); 237 if (recvlen <= 0) 238 return; 239 240 icmsghdr = (struct icmsg_hdr *)&recv_buffer[ 241 sizeof(struct vmbuspipe_hdr)]; 242 if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) { 243 util_fw_version = UTIL_FW_VERSION; 244 fcopy_srv_version = WIN8_SRV_VERSION; 245 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer, 246 util_fw_version, fcopy_srv_version); 247 } else { 248 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ 249 sizeof(struct vmbuspipe_hdr) + 250 sizeof(struct icmsg_hdr)]; 251 252 /* 253 * Stash away this global state for completing the 254 * transaction; note transactions are serialized. 255 */ 256 257 fcopy_transaction.recv_len = recvlen; 258 fcopy_transaction.recv_channel = channel; 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, 5*HZ); 274 return; 275 } 276 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 277 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, 278 VM_PKT_DATA_INBAND, 0); 279 } 280 281 /* Callback when data is received from userspace */ 282 static int fcopy_on_msg(void *msg, int len) 283 { 284 int *val = (int *)msg; 285 286 if (len != sizeof(int)) 287 return -EINVAL; 288 289 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) 290 return fcopy_handle_handshake(*val); 291 292 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) 293 return -EINVAL; 294 295 /* 296 * Complete the transaction by forwarding the result 297 * to the host. But first, cancel the timeout. 298 */ 299 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 300 fcopy_transaction.state = HVUTIL_USERSPACE_RECV; 301 fcopy_respond_to_host(*val); 302 fcopy_transaction.state = HVUTIL_READY; 303 hv_poll_channel(fcopy_transaction.fcopy_context, 304 hv_fcopy_onchannelcallback); 305 } 306 307 return 0; 308 } 309 310 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 } 320 321 int hv_fcopy_init(struct hv_util_service *srv) 322 { 323 recv_buffer = srv->recv_buffer; 324 325 /* 326 * When this driver loads, the user level daemon that 327 * processes the host requests may not yet be running. 328 * Defer processing channel callbacks until the daemon 329 * has registered. 330 */ 331 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 332 333 hvt = hvutil_transport_init(fcopy_devname, 0, 0, 334 fcopy_on_msg, fcopy_on_reset); 335 if (!hvt) 336 return -EFAULT; 337 338 return 0; 339 } 340 341 void hv_fcopy_deinit(void) 342 { 343 fcopy_transaction.state = HVUTIL_DEVICE_DYING; 344 cancel_delayed_work_sync(&fcopy_timeout_work); 345 hvutil_transport_destroy(hvt); 346 } 347