| 1 | /* |
| 2 | * Copyright 6WIND S.A., 2014 |
| 3 | * |
| 4 | * This work is licensed under the terms of the GNU GPL, version 2 or |
| 5 | * (at your option) any later version. See the COPYING file in the |
| 6 | * top-level directory. |
| 7 | */ |
| 8 | |
| 9 | #include "qemu/osdep.h" |
| 10 | #include <sys/socket.h> |
| 11 | #include <sys/un.h> |
| 12 | |
| 13 | #include "qemu/queue.h" |
| 14 | |
| 15 | #include "ivshmem-client.h" |
| 16 | |
| 17 | /* log a message on stdout if verbose=1 */ |
| 18 | #define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \ |
| 19 | if ((client)->verbose) { \ |
| 20 | printf(fmt, ## __VA_ARGS__); \ |
| 21 | } \ |
| 22 | } while (0) |
| 23 | |
| 24 | /* read message from the unix socket */ |
| 25 | static int |
| 26 | ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, int *fd) |
| 27 | { |
| 28 | int ret; |
| 29 | struct msghdr msg; |
| 30 | struct iovec iov[1]; |
| 31 | union { |
| 32 | struct cmsghdr cmsg; |
| 33 | char control[CMSG_SPACE(sizeof(int))]; |
| 34 | } msg_control; |
| 35 | struct cmsghdr *cmsg; |
| 36 | |
| 37 | iov[0].iov_base = index; |
| 38 | iov[0].iov_len = sizeof(*index); |
| 39 | |
| 40 | memset(&msg, 0, sizeof(msg)); |
| 41 | msg.msg_iov = iov; |
| 42 | msg.msg_iovlen = 1; |
| 43 | msg.msg_control = &msg_control; |
| 44 | msg.msg_controllen = sizeof(msg_control); |
| 45 | |
| 46 | ret = recvmsg(client->sock_fd, &msg, 0); |
| 47 | if (ret < sizeof(*index)) { |
| 48 | IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n", |
| 49 | strerror(errno)); |
| 50 | return -1; |
| 51 | } |
| 52 | if (ret == 0) { |
| 53 | IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n"); |
| 54 | return -1; |
| 55 | } |
| 56 | |
| 57 | *index = GINT64_FROM_LE(*index); |
| 58 | *fd = -1; |
| 59 | |
| 60 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| 61 | |
| 62 | if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || |
| 63 | cmsg->cmsg_level != SOL_SOCKET || |
| 64 | cmsg->cmsg_type != SCM_RIGHTS) { |
| 65 | continue; |
| 66 | } |
| 67 | |
| 68 | memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd)); |
| 69 | } |
| 70 | |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | /* free a peer when the server advertises a disconnection or when the |
| 75 | * client is freed */ |
| 76 | static void |
| 77 | ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer) |
| 78 | { |
| 79 | unsigned vector; |
| 80 | |
| 81 | QTAILQ_REMOVE(&client->peer_list, peer, next); |
| 82 | for (vector = 0; vector < peer->vectors_count; vector++) { |
| 83 | close(peer->vectors[vector]); |
| 84 | } |
| 85 | |
| 86 | g_free(peer); |
| 87 | } |
| 88 | |
| 89 | /* handle message coming from server (new peer, new vectors) */ |
| 90 | static int |
| 91 | ivshmem_client_handle_server_msg(IvshmemClient *client) |
| 92 | { |
| 93 | IvshmemClientPeer *peer; |
| 94 | int64_t peer_id; |
| 95 | int ret, fd; |
| 96 | |
| 97 | ret = ivshmem_client_read_one_msg(client, &peer_id, &fd); |
| 98 | if (ret < 0) { |
| 99 | return -1; |
| 100 | } |
| 101 | |
| 102 | /* can return a peer or the local client */ |
| 103 | peer = ivshmem_client_search_peer(client, peer_id); |
| 104 | |
| 105 | /* delete peer */ |
| 106 | if (fd == -1) { |
| 107 | |
| 108 | if (peer == NULL || peer == &client->local) { |
| 109 | IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid " |
| 110 | "peer %" PRId64 "\n", peer_id); |
| 111 | return -1; |
| 112 | } |
| 113 | |
| 114 | IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n", peer_id); |
| 115 | ivshmem_client_free_peer(client, peer); |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | /* new peer */ |
| 120 | if (peer == NULL) { |
| 121 | peer = g_malloc0(sizeof(*peer)); |
| 122 | peer->id = peer_id; |
| 123 | peer->vectors_count = 0; |
| 124 | QTAILQ_INSERT_TAIL(&client->peer_list, peer, next); |
| 125 | IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n", peer_id); |
| 126 | } |
| 127 | |
| 128 | /* new vector */ |
| 129 | IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %" |
| 130 | PRId64 "\n", peer->vectors_count, fd, peer->id); |
| 131 | if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) { |
| 132 | IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing"); |
| 133 | return -1; |
| 134 | } |
| 135 | |
| 136 | peer->vectors[peer->vectors_count] = fd; |
| 137 | peer->vectors_count++; |
| 138 | |
| 139 | return 0; |
| 140 | } |
| 141 | |
| 142 | /* init a new ivshmem client */ |
| 143 | int |
| 144 | ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path, |
| 145 | IvshmemClientNotifCb notif_cb, void *notif_arg, |
| 146 | bool verbose) |
| 147 | { |
| 148 | int ret; |
| 149 | unsigned i; |
| 150 | |
| 151 | memset(client, 0, sizeof(*client)); |
| 152 | |
| 153 | ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path), |
| 154 | "%s", unix_sock_path); |
| 155 | |
| 156 | if (ret < 0 || ret >= sizeof(client->unix_sock_path)) { |
| 157 | IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n"); |
| 158 | return -1; |
| 159 | } |
| 160 | |
| 161 | for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) { |
| 162 | client->local.vectors[i] = -1; |
| 163 | } |
| 164 | |
| 165 | QTAILQ_INIT(&client->peer_list); |
| 166 | client->local.id = -1; |
| 167 | |
| 168 | client->notif_cb = notif_cb; |
| 169 | client->notif_arg = notif_arg; |
| 170 | client->verbose = verbose; |
| 171 | client->shm_fd = -1; |
| 172 | client->sock_fd = -1; |
| 173 | |
| 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | /* create and connect to the unix socket */ |
| 178 | int |
| 179 | ivshmem_client_connect(IvshmemClient *client) |
| 180 | { |
| 181 | struct sockaddr_un s_un; |
| 182 | int fd, ret; |
| 183 | int64_t tmp; |
| 184 | |
| 185 | IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n", |
| 186 | client->unix_sock_path); |
| 187 | |
| 188 | client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0); |
| 189 | if (client->sock_fd < 0) { |
| 190 | IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n", |
| 191 | strerror(errno)); |
| 192 | return -1; |
| 193 | } |
| 194 | |
| 195 | s_un.sun_family = AF_UNIX; |
| 196 | ret = snprintf(s_un.sun_path, sizeof(s_un.sun_path), "%s", |
| 197 | client->unix_sock_path); |
| 198 | if (ret < 0 || ret >= sizeof(s_un.sun_path)) { |
| 199 | IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n"); |
| 200 | goto err_close; |
| 201 | } |
| 202 | |
| 203 | if (connect(client->sock_fd, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) { |
| 204 | IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", s_un.sun_path, |
| 205 | strerror(errno)); |
| 206 | goto err_close; |
| 207 | } |
| 208 | |
| 209 | /* first, we expect a protocol version */ |
| 210 | if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 || |
| 211 | (tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) { |
| 212 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n"); |
| 213 | goto err_close; |
| 214 | } |
| 215 | |
| 216 | /* then, we expect our index + a fd == -1 */ |
| 217 | if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 || |
| 218 | client->local.id < 0 || fd != -1) { |
| 219 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n"); |
| 220 | goto err_close; |
| 221 | } |
| 222 | IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n", client->local.id); |
| 223 | |
| 224 | /* now, we expect shared mem fd + a -1 index, note that shm fd |
| 225 | * is not used */ |
| 226 | if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 || |
| 227 | tmp != -1 || fd < 0) { |
| 228 | if (fd >= 0) { |
| 229 | close(fd); |
| 230 | } |
| 231 | IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n"); |
| 232 | goto err_close; |
| 233 | } |
| 234 | client->shm_fd = fd; |
| 235 | IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n", fd); |
| 236 | |
| 237 | return 0; |
| 238 | |
| 239 | err_close: |
| 240 | close(client->sock_fd); |
| 241 | client->sock_fd = -1; |
| 242 | return -1; |
| 243 | } |
| 244 | |
| 245 | /* close connection to the server, and free all peer structures */ |
| 246 | void |
| 247 | ivshmem_client_close(IvshmemClient *client) |
| 248 | { |
| 249 | IvshmemClientPeer *peer; |
| 250 | unsigned i; |
| 251 | |
| 252 | IVSHMEM_CLIENT_DEBUG(client, "close client\n"); |
| 253 | |
| 254 | while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) { |
| 255 | ivshmem_client_free_peer(client, peer); |
| 256 | } |
| 257 | |
| 258 | close(client->shm_fd); |
| 259 | client->shm_fd = -1; |
| 260 | close(client->sock_fd); |
| 261 | client->sock_fd = -1; |
| 262 | client->local.id = -1; |
| 263 | for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) { |
| 264 | close(client->local.vectors[i]); |
| 265 | client->local.vectors[i] = -1; |
| 266 | } |
| 267 | client->local.vectors_count = 0; |
| 268 | } |
| 269 | |
| 270 | /* get the fd_set according to the unix socket and peer list */ |
| 271 | void |
| 272 | ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd) |
| 273 | { |
| 274 | int fd; |
| 275 | unsigned vector; |
| 276 | |
| 277 | FD_SET(client->sock_fd, fds); |
| 278 | if (client->sock_fd >= *maxfd) { |
| 279 | *maxfd = client->sock_fd + 1; |
| 280 | } |
| 281 | |
| 282 | for (vector = 0; vector < client->local.vectors_count; vector++) { |
| 283 | fd = client->local.vectors[vector]; |
| 284 | FD_SET(fd, fds); |
| 285 | if (fd >= *maxfd) { |
| 286 | *maxfd = fd + 1; |
| 287 | } |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | /* handle events from eventfd: just print a message on notification */ |
| 292 | static int |
| 293 | ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd) |
| 294 | { |
| 295 | IvshmemClientPeer *peer; |
| 296 | uint64_t kick; |
| 297 | unsigned i; |
| 298 | int ret; |
| 299 | |
| 300 | peer = &client->local; |
| 301 | |
| 302 | for (i = 0; i < peer->vectors_count; i++) { |
| 303 | if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) { |
| 304 | continue; |
| 305 | } |
| 306 | |
| 307 | ret = read(peer->vectors[i], &kick, sizeof(kick)); |
| 308 | if (ret < 0) { |
| 309 | return ret; |
| 310 | } |
| 311 | if (ret != sizeof(kick)) { |
| 312 | IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n", ret); |
| 313 | errno = EINVAL; |
| 314 | return -1; |
| 315 | } |
| 316 | IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %" |
| 317 | PRIu64 "\n", peer->vectors[i], i, kick); |
| 318 | if (client->notif_cb != NULL) { |
| 319 | client->notif_cb(client, peer, i, client->notif_arg); |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | return 0; |
| 324 | } |
| 325 | |
| 326 | /* read and handle new messages on the given fd_set */ |
| 327 | int |
| 328 | ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd) |
| 329 | { |
| 330 | if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) && |
| 331 | ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) { |
| 332 | IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() " |
| 333 | "failed\n"); |
| 334 | return -1; |
| 335 | } else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 && |
| 336 | errno != EINTR) { |
| 337 | IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n"); |
| 338 | return -1; |
| 339 | } |
| 340 | |
| 341 | return 0; |
| 342 | } |
| 343 | |
| 344 | /* send a notification on a vector of a peer */ |
| 345 | int |
| 346 | ivshmem_client_notify(const IvshmemClient *client, |
| 347 | const IvshmemClientPeer *peer, unsigned vector) |
| 348 | { |
| 349 | uint64_t kick; |
| 350 | int fd; |
| 351 | |
| 352 | if (vector >= peer->vectors_count) { |
| 353 | IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n", |
| 354 | vector, peer->id); |
| 355 | return -1; |
| 356 | } |
| 357 | fd = peer->vectors[vector]; |
| 358 | IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64 |
| 359 | " on vector %d, fd %d\n", peer->id, vector, fd); |
| 360 | |
| 361 | kick = 1; |
| 362 | if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) { |
| 363 | fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector], |
| 364 | strerror(errno)); |
| 365 | return -1; |
| 366 | } |
| 367 | return 0; |
| 368 | } |
| 369 | |
| 370 | /* send a notification to all vectors of a peer */ |
| 371 | int |
| 372 | ivshmem_client_notify_all_vects(const IvshmemClient *client, |
| 373 | const IvshmemClientPeer *peer) |
| 374 | { |
| 375 | unsigned vector; |
| 376 | int ret = 0; |
| 377 | |
| 378 | for (vector = 0; vector < peer->vectors_count; vector++) { |
| 379 | if (ivshmem_client_notify(client, peer, vector) < 0) { |
| 380 | ret = -1; |
| 381 | } |
| 382 | } |
| 383 | |
| 384 | return ret; |
| 385 | } |
| 386 | |
| 387 | /* send a notification to all peers */ |
| 388 | int |
| 389 | ivshmem_client_notify_broadcast(const IvshmemClient *client) |
| 390 | { |
| 391 | IvshmemClientPeer *peer; |
| 392 | int ret = 0; |
| 393 | |
| 394 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
| 395 | if (ivshmem_client_notify_all_vects(client, peer) < 0) { |
| 396 | ret = -1; |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | return ret; |
| 401 | } |
| 402 | |
| 403 | /* lookup peer from its id */ |
| 404 | IvshmemClientPeer * |
| 405 | ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id) |
| 406 | { |
| 407 | IvshmemClientPeer *peer; |
| 408 | |
| 409 | if (peer_id == client->local.id) { |
| 410 | return &client->local; |
| 411 | } |
| 412 | |
| 413 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
| 414 | if (peer->id == peer_id) { |
| 415 | return peer; |
| 416 | } |
| 417 | } |
| 418 | return NULL; |
| 419 | } |
| 420 | |
| 421 | /* dump our info, the list of peers their vectors on stdout */ |
| 422 | void |
| 423 | ivshmem_client_dump(const IvshmemClient *client) |
| 424 | { |
| 425 | const IvshmemClientPeer *peer; |
| 426 | unsigned vector; |
| 427 | |
| 428 | /* dump local infos */ |
| 429 | peer = &client->local; |
| 430 | printf("our_id = %" PRId64 "\n", peer->id); |
| 431 | for (vector = 0; vector < peer->vectors_count; vector++) { |
| 432 | printf(" vector %d is enabled (fd=%d)\n", vector, |
| 433 | peer->vectors[vector]); |
| 434 | } |
| 435 | |
| 436 | /* dump peers */ |
| 437 | QTAILQ_FOREACH(peer, &client->peer_list, next) { |
| 438 | printf("peer_id = %" PRId64 "\n", peer->id); |
| 439 | |
| 440 | for (vector = 0; vector < peer->vectors_count; vector++) { |
| 441 | printf(" vector %d is enabled (fd=%d)\n", vector, |
| 442 | peer->vectors[vector]); |
| 443 | } |
| 444 | } |
| 445 | } |