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 } fcopy_transaction; 55 56 static void fcopy_respond_to_host(int error); 57 static void fcopy_send_data(struct work_struct *dummy); 58 static void fcopy_timeout_func(struct work_struct *dummy); 59 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func); 60 static DECLARE_WORK(fcopy_send_work, fcopy_send_data); 61 static const char fcopy_devname[] = "vmbus/hv_fcopy"; 62 static u8 *recv_buffer; 63 static struct hvutil_transport *hvt; 64 /* 65 * This state maintains the version number registered by the daemon. 66 */ 67 static int dm_reg_value; 68 69 static 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 76 static 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 86 static 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 92 static 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 } 120 121 static 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 default: 164 out_src = fcopy_transaction.fcopy_msg; 165 out_len = fcopy_transaction.recv_len; 166 break; 167 } 168 169 fcopy_transaction.state = HVUTIL_USERSPACE_REQ; 170 rc = hvutil_transport_send(hvt, out_src, out_len, NULL); 171 if (rc) { 172 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); 173 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 174 fcopy_respond_to_host(HV_E_FAIL); 175 fcopy_transaction.state = HVUTIL_READY; 176 } 177 } 178 kfree(smsg_out); 179 180 return; 181 } 182 183 /* 184 * Send a response back to the host. 185 */ 186 187 static void 188 fcopy_respond_to_host(int error) 189 { 190 struct icmsg_hdr *icmsghdr; 191 u32 buf_len; 192 struct vmbus_channel *channel; 193 u64 req_id; 194 195 /* 196 * Copy the global state for completing the transaction. Note that 197 * only one transaction can be active at a time. This is guaranteed 198 * by the file copy protocol implemented by the host. Furthermore, 199 * the "transaction active" state we maintain ensures that there can 200 * only be one active transaction at a time. 201 */ 202 203 buf_len = fcopy_transaction.recv_len; 204 channel = fcopy_transaction.recv_channel; 205 req_id = fcopy_transaction.recv_req_id; 206 207 icmsghdr = (struct icmsg_hdr *) 208 &recv_buffer[sizeof(struct vmbuspipe_hdr)]; 209 210 if (channel->onchannel_callback == NULL) 211 /* 212 * We have raced with util driver being unloaded; 213 * silently return. 214 */ 215 return; 216 217 icmsghdr->status = error; 218 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 219 vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, 220 VM_PKT_DATA_INBAND, 0); 221 } 222 223 void hv_fcopy_onchannelcallback(void *context) 224 { 225 struct vmbus_channel *channel = context; 226 u32 recvlen; 227 u64 requestid; 228 struct hv_fcopy_hdr *fcopy_msg; 229 struct icmsg_hdr *icmsghdr; 230 struct icmsg_negotiate *negop = NULL; 231 int util_fw_version; 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 util_fw_version = UTIL_FW_VERSION; 246 fcopy_srv_version = WIN8_SRV_VERSION; 247 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer, 248 util_fw_version, fcopy_srv_version); 249 } else { 250 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ 251 sizeof(struct vmbuspipe_hdr) + 252 sizeof(struct icmsg_hdr)]; 253 254 /* 255 * Stash away this global state for completing the 256 * transaction; note transactions are serialized. 257 */ 258 259 fcopy_transaction.recv_len = recvlen; 260 fcopy_transaction.recv_req_id = requestid; 261 fcopy_transaction.fcopy_msg = fcopy_msg; 262 263 if (fcopy_transaction.state < HVUTIL_READY) { 264 /* Userspace is not registered yet */ 265 fcopy_respond_to_host(HV_E_FAIL); 266 return; 267 } 268 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED; 269 270 /* 271 * Send the information to the user-level daemon. 272 */ 273 schedule_work(&fcopy_send_work); 274 schedule_delayed_work(&fcopy_timeout_work, 275 HV_UTIL_TIMEOUT * HZ); 276 return; 277 } 278 icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; 279 vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, 280 VM_PKT_DATA_INBAND, 0); 281 } 282 283 /* Callback when data is received from userspace */ 284 static int fcopy_on_msg(void *msg, int len) 285 { 286 int *val = (int *)msg; 287 288 if (len != sizeof(int)) 289 return -EINVAL; 290 291 if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) 292 return fcopy_handle_handshake(*val); 293 294 if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) 295 return -EINVAL; 296 297 /* 298 * Complete the transaction by forwarding the result 299 * to the host. But first, cancel the timeout. 300 */ 301 if (cancel_delayed_work_sync(&fcopy_timeout_work)) { 302 fcopy_transaction.state = HVUTIL_USERSPACE_RECV; 303 fcopy_respond_to_host(*val); 304 hv_poll_channel(fcopy_transaction.recv_channel, 305 fcopy_poll_wrapper); 306 } 307 308 return 0; 309 } 310 311 static void fcopy_on_reset(void) 312 { 313 /* 314 * The daemon has exited; reset the state. 315 */ 316 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 317 318 if (cancel_delayed_work_sync(&fcopy_timeout_work)) 319 fcopy_respond_to_host(HV_E_FAIL); 320 } 321 322 int hv_fcopy_init(struct hv_util_service *srv) 323 { 324 recv_buffer = srv->recv_buffer; 325 fcopy_transaction.recv_channel = srv->channel; 326 327 /* 328 * When this driver loads, the user level daemon that 329 * processes the host requests may not yet be running. 330 * Defer processing channel callbacks until the daemon 331 * has registered. 332 */ 333 fcopy_transaction.state = HVUTIL_DEVICE_INIT; 334 335 hvt = hvutil_transport_init(fcopy_devname, 0, 0, 336 fcopy_on_msg, fcopy_on_reset); 337 if (!hvt) 338 return -EFAULT; 339 340 return 0; 341 } 342 343 void hv_fcopy_deinit(void) 344 { 345 fcopy_transaction.state = HVUTIL_DEVICE_DYING; 346 cancel_delayed_work_sync(&fcopy_timeout_work); 347 hvutil_transport_destroy(hvt); 348 } 349