Googler | 9398cc3 | 2022-12-02 17:21:52 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | #include <linux/etherdevice.h> |
| 3 | #include <linux/if_tap.h> |
| 4 | #include <linux/if_vlan.h> |
| 5 | #include <linux/interrupt.h> |
| 6 | #include <linux/nsproxy.h> |
| 7 | #include <linux/compat.h> |
| 8 | #include <linux/if_tun.h> |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/skbuff.h> |
| 11 | #include <linux/cache.h> |
| 12 | #include <linux/sched/signal.h> |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/wait.h> |
| 16 | #include <linux/cdev.h> |
| 17 | #include <linux/idr.h> |
| 18 | #include <linux/fs.h> |
| 19 | #include <linux/uio.h> |
| 20 | |
| 21 | #include <net/net_namespace.h> |
| 22 | #include <net/rtnetlink.h> |
| 23 | #include <net/sock.h> |
| 24 | #include <linux/virtio_net.h> |
| 25 | #include <linux/skb_array.h> |
| 26 | |
| 27 | #define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) |
| 28 | |
| 29 | #define TAP_VNET_LE 0x80000000 |
| 30 | #define TAP_VNET_BE 0x40000000 |
| 31 | |
| 32 | #ifdef CONFIG_TUN_VNET_CROSS_LE |
| 33 | static inline bool tap_legacy_is_little_endian(struct tap_queue *q) |
| 34 | { |
| 35 | return q->flags & TAP_VNET_BE ? false : |
| 36 | virtio_legacy_is_little_endian(); |
| 37 | } |
| 38 | |
| 39 | static long tap_get_vnet_be(struct tap_queue *q, int __user *sp) |
| 40 | { |
| 41 | int s = !!(q->flags & TAP_VNET_BE); |
| 42 | |
| 43 | if (put_user(s, sp)) |
| 44 | return -EFAULT; |
| 45 | |
| 46 | return 0; |
| 47 | } |
| 48 | |
| 49 | static long tap_set_vnet_be(struct tap_queue *q, int __user *sp) |
| 50 | { |
| 51 | int s; |
| 52 | |
| 53 | if (get_user(s, sp)) |
| 54 | return -EFAULT; |
| 55 | |
| 56 | if (s) |
| 57 | q->flags |= TAP_VNET_BE; |
| 58 | else |
| 59 | q->flags &= ~TAP_VNET_BE; |
| 60 | |
| 61 | return 0; |
| 62 | } |
| 63 | #else |
| 64 | static inline bool tap_legacy_is_little_endian(struct tap_queue *q) |
| 65 | { |
| 66 | return virtio_legacy_is_little_endian(); |
| 67 | } |
| 68 | |
| 69 | static long tap_get_vnet_be(struct tap_queue *q, int __user *argp) |
| 70 | { |
| 71 | return -EINVAL; |
| 72 | } |
| 73 | |
| 74 | static long tap_set_vnet_be(struct tap_queue *q, int __user *argp) |
| 75 | { |
| 76 | return -EINVAL; |
| 77 | } |
| 78 | #endif /* CONFIG_TUN_VNET_CROSS_LE */ |
| 79 | |
| 80 | static inline bool tap_is_little_endian(struct tap_queue *q) |
| 81 | { |
| 82 | return q->flags & TAP_VNET_LE || |
| 83 | tap_legacy_is_little_endian(q); |
| 84 | } |
| 85 | |
| 86 | static inline u16 tap16_to_cpu(struct tap_queue *q, __virtio16 val) |
| 87 | { |
| 88 | return __virtio16_to_cpu(tap_is_little_endian(q), val); |
| 89 | } |
| 90 | |
| 91 | static inline __virtio16 cpu_to_tap16(struct tap_queue *q, u16 val) |
| 92 | { |
| 93 | return __cpu_to_virtio16(tap_is_little_endian(q), val); |
| 94 | } |
| 95 | |
| 96 | static struct proto tap_proto = { |
| 97 | .name = "tap", |
| 98 | .owner = THIS_MODULE, |
| 99 | .obj_size = sizeof(struct tap_queue), |
| 100 | }; |
| 101 | |
| 102 | #define TAP_NUM_DEVS (1U << MINORBITS) |
| 103 | |
| 104 | static LIST_HEAD(major_list); |
| 105 | |
| 106 | struct major_info { |
| 107 | struct rcu_head rcu; |
| 108 | dev_t major; |
| 109 | struct idr minor_idr; |
| 110 | spinlock_t minor_lock; |
| 111 | const char *device_name; |
| 112 | struct list_head next; |
| 113 | }; |
| 114 | |
| 115 | #define GOODCOPY_LEN 128 |
| 116 | |
| 117 | static const struct proto_ops tap_socket_ops; |
| 118 | |
| 119 | #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) |
| 120 | #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST) |
| 121 | |
| 122 | static struct tap_dev *tap_dev_get_rcu(const struct net_device *dev) |
| 123 | { |
| 124 | return rcu_dereference(dev->rx_handler_data); |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * RCU usage: |
| 129 | * The tap_queue and the macvlan_dev are loosely coupled, the |
| 130 | * pointers from one to the other can only be read while rcu_read_lock |
| 131 | * or rtnl is held. |
| 132 | * |
| 133 | * Both the file and the macvlan_dev hold a reference on the tap_queue |
| 134 | * through sock_hold(&q->sk). When the macvlan_dev goes away first, |
| 135 | * q->vlan becomes inaccessible. When the files gets closed, |
| 136 | * tap_get_queue() fails. |
| 137 | * |
| 138 | * There may still be references to the struct sock inside of the |
| 139 | * queue from outbound SKBs, but these never reference back to the |
| 140 | * file or the dev. The data structure is freed through __sk_free |
| 141 | * when both our references and any pending SKBs are gone. |
| 142 | */ |
| 143 | |
| 144 | static int tap_enable_queue(struct tap_dev *tap, struct file *file, |
| 145 | struct tap_queue *q) |
| 146 | { |
| 147 | int err = -EINVAL; |
| 148 | |
| 149 | ASSERT_RTNL(); |
| 150 | |
| 151 | if (q->enabled) |
| 152 | goto out; |
| 153 | |
| 154 | err = 0; |
| 155 | rcu_assign_pointer(tap->taps[tap->numvtaps], q); |
| 156 | q->queue_index = tap->numvtaps; |
| 157 | q->enabled = true; |
| 158 | |
| 159 | tap->numvtaps++; |
| 160 | out: |
| 161 | return err; |
| 162 | } |
| 163 | |
| 164 | /* Requires RTNL */ |
| 165 | static int tap_set_queue(struct tap_dev *tap, struct file *file, |
| 166 | struct tap_queue *q) |
| 167 | { |
| 168 | if (tap->numqueues == MAX_TAP_QUEUES) |
| 169 | return -EBUSY; |
| 170 | |
| 171 | rcu_assign_pointer(q->tap, tap); |
| 172 | rcu_assign_pointer(tap->taps[tap->numvtaps], q); |
| 173 | sock_hold(&q->sk); |
| 174 | |
| 175 | q->file = file; |
| 176 | q->queue_index = tap->numvtaps; |
| 177 | q->enabled = true; |
| 178 | file->private_data = q; |
| 179 | list_add_tail(&q->next, &tap->queue_list); |
| 180 | |
| 181 | tap->numvtaps++; |
| 182 | tap->numqueues++; |
| 183 | |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | static int tap_disable_queue(struct tap_queue *q) |
| 188 | { |
| 189 | struct tap_dev *tap; |
| 190 | struct tap_queue *nq; |
| 191 | |
| 192 | ASSERT_RTNL(); |
| 193 | if (!q->enabled) |
| 194 | return -EINVAL; |
| 195 | |
| 196 | tap = rtnl_dereference(q->tap); |
| 197 | |
| 198 | if (tap) { |
| 199 | int index = q->queue_index; |
| 200 | BUG_ON(index >= tap->numvtaps); |
| 201 | nq = rtnl_dereference(tap->taps[tap->numvtaps - 1]); |
| 202 | nq->queue_index = index; |
| 203 | |
| 204 | rcu_assign_pointer(tap->taps[index], nq); |
| 205 | RCU_INIT_POINTER(tap->taps[tap->numvtaps - 1], NULL); |
| 206 | q->enabled = false; |
| 207 | |
| 208 | tap->numvtaps--; |
| 209 | } |
| 210 | |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * The file owning the queue got closed, give up both |
| 216 | * the reference that the files holds as well as the |
| 217 | * one from the macvlan_dev if that still exists. |
| 218 | * |
| 219 | * Using the spinlock makes sure that we don't get |
| 220 | * to the queue again after destroying it. |
| 221 | */ |
| 222 | static void tap_put_queue(struct tap_queue *q) |
| 223 | { |
| 224 | struct tap_dev *tap; |
| 225 | |
| 226 | rtnl_lock(); |
| 227 | tap = rtnl_dereference(q->tap); |
| 228 | |
| 229 | if (tap) { |
| 230 | if (q->enabled) |
| 231 | BUG_ON(tap_disable_queue(q)); |
| 232 | |
| 233 | tap->numqueues--; |
| 234 | RCU_INIT_POINTER(q->tap, NULL); |
| 235 | sock_put(&q->sk); |
| 236 | list_del_init(&q->next); |
| 237 | } |
| 238 | |
| 239 | rtnl_unlock(); |
| 240 | |
| 241 | synchronize_rcu(); |
| 242 | sock_put(&q->sk); |
| 243 | } |
| 244 | |
| 245 | /* |
| 246 | * Select a queue based on the rxq of the device on which this packet |
| 247 | * arrived. If the incoming device is not mq, calculate a flow hash |
| 248 | * to select a queue. If all fails, find the first available queue. |
| 249 | * Cache vlan->numvtaps since it can become zero during the execution |
| 250 | * of this function. |
| 251 | */ |
| 252 | static struct tap_queue *tap_get_queue(struct tap_dev *tap, |
| 253 | struct sk_buff *skb) |
| 254 | { |
| 255 | struct tap_queue *queue = NULL; |
| 256 | /* Access to taps array is protected by rcu, but access to numvtaps |
| 257 | * isn't. Below we use it to lookup a queue, but treat it as a hint |
| 258 | * and validate that the result isn't NULL - in case we are |
| 259 | * racing against queue removal. |
| 260 | */ |
| 261 | int numvtaps = READ_ONCE(tap->numvtaps); |
| 262 | __u32 rxq; |
| 263 | |
| 264 | if (!numvtaps) |
| 265 | goto out; |
| 266 | |
| 267 | if (numvtaps == 1) |
| 268 | goto single; |
| 269 | |
| 270 | /* Check if we can use flow to select a queue */ |
| 271 | rxq = skb_get_hash(skb); |
| 272 | if (rxq) { |
| 273 | queue = rcu_dereference(tap->taps[rxq % numvtaps]); |
| 274 | goto out; |
| 275 | } |
| 276 | |
| 277 | if (likely(skb_rx_queue_recorded(skb))) { |
| 278 | rxq = skb_get_rx_queue(skb); |
| 279 | |
| 280 | while (unlikely(rxq >= numvtaps)) |
| 281 | rxq -= numvtaps; |
| 282 | |
| 283 | queue = rcu_dereference(tap->taps[rxq]); |
| 284 | goto out; |
| 285 | } |
| 286 | |
| 287 | single: |
| 288 | queue = rcu_dereference(tap->taps[0]); |
| 289 | out: |
| 290 | return queue; |
| 291 | } |
| 292 | |
| 293 | /* |
| 294 | * The net_device is going away, give up the reference |
| 295 | * that it holds on all queues and safely set the pointer |
| 296 | * from the queues to NULL. |
| 297 | */ |
| 298 | void tap_del_queues(struct tap_dev *tap) |
| 299 | { |
| 300 | struct tap_queue *q, *tmp; |
| 301 | |
| 302 | ASSERT_RTNL(); |
| 303 | list_for_each_entry_safe(q, tmp, &tap->queue_list, next) { |
| 304 | list_del_init(&q->next); |
| 305 | RCU_INIT_POINTER(q->tap, NULL); |
| 306 | if (q->enabled) |
| 307 | tap->numvtaps--; |
| 308 | tap->numqueues--; |
| 309 | sock_put(&q->sk); |
| 310 | } |
| 311 | BUG_ON(tap->numvtaps); |
| 312 | BUG_ON(tap->numqueues); |
| 313 | /* guarantee that any future tap_set_queue will fail */ |
| 314 | tap->numvtaps = MAX_TAP_QUEUES; |
| 315 | } |
| 316 | EXPORT_SYMBOL_GPL(tap_del_queues); |
| 317 | |
| 318 | rx_handler_result_t tap_handle_frame(struct sk_buff **pskb) |
| 319 | { |
| 320 | struct sk_buff *skb = *pskb; |
| 321 | struct net_device *dev = skb->dev; |
| 322 | struct tap_dev *tap; |
| 323 | struct tap_queue *q; |
| 324 | netdev_features_t features = TAP_FEATURES; |
| 325 | |
| 326 | tap = tap_dev_get_rcu(dev); |
| 327 | if (!tap) |
| 328 | return RX_HANDLER_PASS; |
| 329 | |
| 330 | q = tap_get_queue(tap, skb); |
| 331 | if (!q) |
| 332 | return RX_HANDLER_PASS; |
| 333 | |
| 334 | skb_push(skb, ETH_HLEN); |
| 335 | |
| 336 | /* Apply the forward feature mask so that we perform segmentation |
| 337 | * according to users wishes. This only works if VNET_HDR is |
| 338 | * enabled. |
| 339 | */ |
| 340 | if (q->flags & IFF_VNET_HDR) |
| 341 | features |= tap->tap_features; |
| 342 | if (netif_needs_gso(skb, features)) { |
| 343 | struct sk_buff *segs = __skb_gso_segment(skb, features, false); |
| 344 | |
| 345 | if (IS_ERR(segs)) |
| 346 | goto drop; |
| 347 | |
| 348 | if (!segs) { |
| 349 | if (ptr_ring_produce(&q->ring, skb)) |
| 350 | goto drop; |
| 351 | goto wake_up; |
| 352 | } |
| 353 | |
| 354 | consume_skb(skb); |
| 355 | while (segs) { |
| 356 | struct sk_buff *nskb = segs->next; |
| 357 | |
| 358 | segs->next = NULL; |
| 359 | if (ptr_ring_produce(&q->ring, segs)) { |
| 360 | kfree_skb(segs); |
| 361 | kfree_skb_list(nskb); |
| 362 | break; |
| 363 | } |
| 364 | segs = nskb; |
| 365 | } |
| 366 | } else { |
| 367 | /* If we receive a partial checksum and the tap side |
| 368 | * doesn't support checksum offload, compute the checksum. |
| 369 | * Note: it doesn't matter which checksum feature to |
| 370 | * check, we either support them all or none. |
| 371 | */ |
| 372 | if (skb->ip_summed == CHECKSUM_PARTIAL && |
| 373 | !(features & NETIF_F_CSUM_MASK) && |
| 374 | skb_checksum_help(skb)) |
| 375 | goto drop; |
| 376 | if (ptr_ring_produce(&q->ring, skb)) |
| 377 | goto drop; |
| 378 | } |
| 379 | |
| 380 | wake_up: |
| 381 | wake_up_interruptible_poll(sk_sleep(&q->sk), EPOLLIN | EPOLLRDNORM | EPOLLRDBAND); |
| 382 | return RX_HANDLER_CONSUMED; |
| 383 | |
| 384 | drop: |
| 385 | /* Count errors/drops only here, thus don't care about args. */ |
| 386 | if (tap->count_rx_dropped) |
| 387 | tap->count_rx_dropped(tap); |
| 388 | kfree_skb(skb); |
| 389 | return RX_HANDLER_CONSUMED; |
| 390 | } |
| 391 | EXPORT_SYMBOL_GPL(tap_handle_frame); |
| 392 | |
| 393 | static struct major_info *tap_get_major(int major) |
| 394 | { |
| 395 | struct major_info *tap_major; |
| 396 | |
| 397 | list_for_each_entry_rcu(tap_major, &major_list, next) { |
| 398 | if (tap_major->major == major) |
| 399 | return tap_major; |
| 400 | } |
| 401 | |
| 402 | return NULL; |
| 403 | } |
| 404 | |
| 405 | int tap_get_minor(dev_t major, struct tap_dev *tap) |
| 406 | { |
| 407 | int retval = -ENOMEM; |
| 408 | struct major_info *tap_major; |
| 409 | |
| 410 | rcu_read_lock(); |
| 411 | tap_major = tap_get_major(MAJOR(major)); |
| 412 | if (!tap_major) { |
| 413 | retval = -EINVAL; |
| 414 | goto unlock; |
| 415 | } |
| 416 | |
| 417 | spin_lock(&tap_major->minor_lock); |
| 418 | retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC); |
| 419 | if (retval >= 0) { |
| 420 | tap->minor = retval; |
| 421 | } else if (retval == -ENOSPC) { |
| 422 | netdev_err(tap->dev, "Too many tap devices\n"); |
| 423 | retval = -EINVAL; |
| 424 | } |
| 425 | spin_unlock(&tap_major->minor_lock); |
| 426 | |
| 427 | unlock: |
| 428 | rcu_read_unlock(); |
| 429 | return retval < 0 ? retval : 0; |
| 430 | } |
| 431 | EXPORT_SYMBOL_GPL(tap_get_minor); |
| 432 | |
| 433 | void tap_free_minor(dev_t major, struct tap_dev *tap) |
| 434 | { |
| 435 | struct major_info *tap_major; |
| 436 | |
| 437 | rcu_read_lock(); |
| 438 | tap_major = tap_get_major(MAJOR(major)); |
| 439 | if (!tap_major) { |
| 440 | goto unlock; |
| 441 | } |
| 442 | |
| 443 | spin_lock(&tap_major->minor_lock); |
| 444 | if (tap->minor) { |
| 445 | idr_remove(&tap_major->minor_idr, tap->minor); |
| 446 | tap->minor = 0; |
| 447 | } |
| 448 | spin_unlock(&tap_major->minor_lock); |
| 449 | |
| 450 | unlock: |
| 451 | rcu_read_unlock(); |
| 452 | } |
| 453 | EXPORT_SYMBOL_GPL(tap_free_minor); |
| 454 | |
| 455 | static struct tap_dev *dev_get_by_tap_file(int major, int minor) |
| 456 | { |
| 457 | struct net_device *dev = NULL; |
| 458 | struct tap_dev *tap; |
| 459 | struct major_info *tap_major; |
| 460 | |
| 461 | rcu_read_lock(); |
| 462 | tap_major = tap_get_major(major); |
| 463 | if (!tap_major) { |
| 464 | tap = NULL; |
| 465 | goto unlock; |
| 466 | } |
| 467 | |
| 468 | spin_lock(&tap_major->minor_lock); |
| 469 | tap = idr_find(&tap_major->minor_idr, minor); |
| 470 | if (tap) { |
| 471 | dev = tap->dev; |
| 472 | dev_hold(dev); |
| 473 | } |
| 474 | spin_unlock(&tap_major->minor_lock); |
| 475 | |
| 476 | unlock: |
| 477 | rcu_read_unlock(); |
| 478 | return tap; |
| 479 | } |
| 480 | |
| 481 | static void tap_sock_write_space(struct sock *sk) |
| 482 | { |
| 483 | wait_queue_head_t *wqueue; |
| 484 | |
| 485 | if (!sock_writeable(sk) || |
| 486 | !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags)) |
| 487 | return; |
| 488 | |
| 489 | wqueue = sk_sleep(sk); |
| 490 | if (wqueue && waitqueue_active(wqueue)) |
| 491 | wake_up_interruptible_poll(wqueue, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); |
| 492 | } |
| 493 | |
| 494 | static void tap_sock_destruct(struct sock *sk) |
| 495 | { |
| 496 | struct tap_queue *q = container_of(sk, struct tap_queue, sk); |
| 497 | |
| 498 | ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb); |
| 499 | } |
| 500 | |
| 501 | static int tap_open(struct inode *inode, struct file *file) |
| 502 | { |
| 503 | struct net *net = current->nsproxy->net_ns; |
| 504 | struct tap_dev *tap; |
| 505 | struct tap_queue *q; |
| 506 | int err = -ENODEV; |
| 507 | |
| 508 | rtnl_lock(); |
| 509 | tap = dev_get_by_tap_file(imajor(inode), iminor(inode)); |
| 510 | if (!tap) |
| 511 | goto err; |
| 512 | |
| 513 | err = -ENOMEM; |
| 514 | q = (struct tap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, |
| 515 | &tap_proto, 0); |
| 516 | if (!q) |
| 517 | goto err; |
| 518 | if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) { |
| 519 | sk_free(&q->sk); |
| 520 | goto err; |
| 521 | } |
| 522 | |
| 523 | init_waitqueue_head(&q->sock.wq.wait); |
| 524 | q->sock.type = SOCK_RAW; |
| 525 | q->sock.state = SS_CONNECTED; |
| 526 | q->sock.file = file; |
| 527 | q->sock.ops = &tap_socket_ops; |
| 528 | sock_init_data(&q->sock, &q->sk); |
| 529 | q->sk.sk_write_space = tap_sock_write_space; |
| 530 | q->sk.sk_destruct = tap_sock_destruct; |
| 531 | q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; |
| 532 | q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); |
| 533 | |
| 534 | /* |
| 535 | * so far only KVM virtio_net uses tap, enable zero copy between |
| 536 | * guest kernel and host kernel when lower device supports zerocopy |
| 537 | * |
| 538 | * The macvlan supports zerocopy iff the lower device supports zero |
| 539 | * copy so we don't have to look at the lower device directly. |
| 540 | */ |
| 541 | if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG)) |
| 542 | sock_set_flag(&q->sk, SOCK_ZEROCOPY); |
| 543 | |
| 544 | err = tap_set_queue(tap, file, q); |
| 545 | if (err) { |
| 546 | /* tap_sock_destruct() will take care of freeing ptr_ring */ |
| 547 | goto err_put; |
| 548 | } |
| 549 | |
| 550 | dev_put(tap->dev); |
| 551 | |
| 552 | rtnl_unlock(); |
| 553 | return err; |
| 554 | |
| 555 | err_put: |
| 556 | sock_put(&q->sk); |
| 557 | err: |
| 558 | if (tap) |
| 559 | dev_put(tap->dev); |
| 560 | |
| 561 | rtnl_unlock(); |
| 562 | return err; |
| 563 | } |
| 564 | |
| 565 | static int tap_release(struct inode *inode, struct file *file) |
| 566 | { |
| 567 | struct tap_queue *q = file->private_data; |
| 568 | tap_put_queue(q); |
| 569 | return 0; |
| 570 | } |
| 571 | |
| 572 | static __poll_t tap_poll(struct file *file, poll_table *wait) |
| 573 | { |
| 574 | struct tap_queue *q = file->private_data; |
| 575 | __poll_t mask = EPOLLERR; |
| 576 | |
| 577 | if (!q) |
| 578 | goto out; |
| 579 | |
| 580 | mask = 0; |
| 581 | poll_wait(file, &q->sock.wq.wait, wait); |
| 582 | |
| 583 | if (!ptr_ring_empty(&q->ring)) |
| 584 | mask |= EPOLLIN | EPOLLRDNORM; |
| 585 | |
| 586 | if (sock_writeable(&q->sk) || |
| 587 | (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) && |
| 588 | sock_writeable(&q->sk))) |
| 589 | mask |= EPOLLOUT | EPOLLWRNORM; |
| 590 | |
| 591 | out: |
| 592 | return mask; |
| 593 | } |
| 594 | |
| 595 | static inline struct sk_buff *tap_alloc_skb(struct sock *sk, size_t prepad, |
| 596 | size_t len, size_t linear, |
| 597 | int noblock, int *err) |
| 598 | { |
| 599 | struct sk_buff *skb; |
| 600 | |
| 601 | /* Under a page? Don't bother with paged skb. */ |
| 602 | if (prepad + len < PAGE_SIZE || !linear) |
| 603 | linear = len; |
| 604 | |
| 605 | skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, |
| 606 | err, 0); |
| 607 | if (!skb) |
| 608 | return NULL; |
| 609 | |
| 610 | skb_reserve(skb, prepad); |
| 611 | skb_put(skb, linear); |
| 612 | skb->data_len = len - linear; |
| 613 | skb->len += len - linear; |
| 614 | |
| 615 | return skb; |
| 616 | } |
| 617 | |
| 618 | /* Neighbour code has some assumptions on HH_DATA_MOD alignment */ |
| 619 | #define TAP_RESERVE HH_DATA_OFF(ETH_HLEN) |
| 620 | |
| 621 | /* Get packet from user space buffer */ |
| 622 | static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, |
| 623 | struct iov_iter *from, int noblock) |
| 624 | { |
| 625 | int good_linear = SKB_MAX_HEAD(TAP_RESERVE); |
| 626 | struct sk_buff *skb; |
| 627 | struct tap_dev *tap; |
| 628 | unsigned long total_len = iov_iter_count(from); |
| 629 | unsigned long len = total_len; |
| 630 | int err; |
| 631 | struct virtio_net_hdr vnet_hdr = { 0 }; |
| 632 | int vnet_hdr_len = 0; |
| 633 | int copylen = 0; |
| 634 | int depth; |
| 635 | bool zerocopy = false; |
| 636 | size_t linear; |
| 637 | |
| 638 | if (q->flags & IFF_VNET_HDR) { |
| 639 | vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); |
| 640 | |
| 641 | err = -EINVAL; |
| 642 | if (len < vnet_hdr_len) |
| 643 | goto err; |
| 644 | len -= vnet_hdr_len; |
| 645 | |
| 646 | err = -EFAULT; |
| 647 | if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) |
| 648 | goto err; |
| 649 | iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr)); |
| 650 | if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && |
| 651 | tap16_to_cpu(q, vnet_hdr.csum_start) + |
| 652 | tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > |
| 653 | tap16_to_cpu(q, vnet_hdr.hdr_len)) |
| 654 | vnet_hdr.hdr_len = cpu_to_tap16(q, |
| 655 | tap16_to_cpu(q, vnet_hdr.csum_start) + |
| 656 | tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); |
| 657 | err = -EINVAL; |
| 658 | if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) |
| 659 | goto err; |
| 660 | } |
| 661 | |
| 662 | err = -EINVAL; |
| 663 | if (unlikely(len < ETH_HLEN)) |
| 664 | goto err; |
| 665 | |
| 666 | if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { |
| 667 | struct iov_iter i; |
| 668 | |
| 669 | copylen = vnet_hdr.hdr_len ? |
| 670 | tap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; |
| 671 | if (copylen > good_linear) |
| 672 | copylen = good_linear; |
| 673 | else if (copylen < ETH_HLEN) |
| 674 | copylen = ETH_HLEN; |
| 675 | linear = copylen; |
| 676 | i = *from; |
| 677 | iov_iter_advance(&i, copylen); |
| 678 | if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) |
| 679 | zerocopy = true; |
| 680 | } |
| 681 | |
| 682 | if (!zerocopy) { |
| 683 | copylen = len; |
| 684 | linear = tap16_to_cpu(q, vnet_hdr.hdr_len); |
| 685 | if (linear > good_linear) |
| 686 | linear = good_linear; |
| 687 | else if (linear < ETH_HLEN) |
| 688 | linear = ETH_HLEN; |
| 689 | } |
| 690 | |
| 691 | skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen, |
| 692 | linear, noblock, &err); |
| 693 | if (!skb) |
| 694 | goto err; |
| 695 | |
| 696 | if (zerocopy) |
| 697 | err = zerocopy_sg_from_iter(skb, from); |
| 698 | else |
| 699 | err = skb_copy_datagram_from_iter(skb, 0, from, len); |
| 700 | |
| 701 | if (err) |
| 702 | goto err_kfree; |
| 703 | |
| 704 | skb_set_network_header(skb, ETH_HLEN); |
| 705 | skb_reset_mac_header(skb); |
| 706 | skb->protocol = eth_hdr(skb)->h_proto; |
| 707 | |
| 708 | if (vnet_hdr_len) { |
| 709 | err = virtio_net_hdr_to_skb(skb, &vnet_hdr, |
| 710 | tap_is_little_endian(q)); |
| 711 | if (err) |
| 712 | goto err_kfree; |
| 713 | } |
| 714 | |
| 715 | skb_probe_transport_header(skb); |
| 716 | |
| 717 | /* Move network header to the right position for VLAN tagged packets */ |
| 718 | if ((skb->protocol == htons(ETH_P_8021Q) || |
| 719 | skb->protocol == htons(ETH_P_8021AD)) && |
| 720 | __vlan_get_protocol(skb, skb->protocol, &depth) != 0) |
| 721 | skb_set_network_header(skb, depth); |
| 722 | |
| 723 | rcu_read_lock(); |
| 724 | tap = rcu_dereference(q->tap); |
| 725 | /* copy skb_ubuf_info for callback when skb has no error */ |
| 726 | if (zerocopy) { |
| 727 | skb_shinfo(skb)->destructor_arg = msg_control; |
| 728 | skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; |
| 729 | skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; |
| 730 | } else if (msg_control) { |
| 731 | struct ubuf_info *uarg = msg_control; |
| 732 | uarg->callback(uarg, false); |
| 733 | } |
| 734 | |
| 735 | if (tap) { |
| 736 | skb->dev = tap->dev; |
| 737 | dev_queue_xmit(skb); |
| 738 | } else { |
| 739 | kfree_skb(skb); |
| 740 | } |
| 741 | rcu_read_unlock(); |
| 742 | |
| 743 | return total_len; |
| 744 | |
| 745 | err_kfree: |
| 746 | kfree_skb(skb); |
| 747 | |
| 748 | err: |
| 749 | rcu_read_lock(); |
| 750 | tap = rcu_dereference(q->tap); |
| 751 | if (tap && tap->count_tx_dropped) |
| 752 | tap->count_tx_dropped(tap); |
| 753 | rcu_read_unlock(); |
| 754 | |
| 755 | return err; |
| 756 | } |
| 757 | |
| 758 | static ssize_t tap_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| 759 | { |
| 760 | struct file *file = iocb->ki_filp; |
| 761 | struct tap_queue *q = file->private_data; |
| 762 | |
| 763 | return tap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK); |
| 764 | } |
| 765 | |
| 766 | /* Put packet to the user space buffer */ |
| 767 | static ssize_t tap_put_user(struct tap_queue *q, |
| 768 | const struct sk_buff *skb, |
| 769 | struct iov_iter *iter) |
| 770 | { |
| 771 | int ret; |
| 772 | int vnet_hdr_len = 0; |
| 773 | int vlan_offset = 0; |
| 774 | int total; |
| 775 | |
| 776 | if (q->flags & IFF_VNET_HDR) { |
| 777 | int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0; |
| 778 | struct virtio_net_hdr vnet_hdr; |
| 779 | |
| 780 | vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); |
| 781 | if (iov_iter_count(iter) < vnet_hdr_len) |
| 782 | return -EINVAL; |
| 783 | |
| 784 | if (virtio_net_hdr_from_skb(skb, &vnet_hdr, |
| 785 | tap_is_little_endian(q), true, |
| 786 | vlan_hlen)) |
| 787 | BUG(); |
| 788 | |
| 789 | if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) != |
| 790 | sizeof(vnet_hdr)) |
| 791 | return -EFAULT; |
| 792 | |
| 793 | iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr)); |
| 794 | } |
| 795 | total = vnet_hdr_len; |
| 796 | total += skb->len; |
| 797 | |
| 798 | if (skb_vlan_tag_present(skb)) { |
| 799 | struct { |
| 800 | __be16 h_vlan_proto; |
| 801 | __be16 h_vlan_TCI; |
| 802 | } veth; |
| 803 | veth.h_vlan_proto = skb->vlan_proto; |
| 804 | veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); |
| 805 | |
| 806 | vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); |
| 807 | total += VLAN_HLEN; |
| 808 | |
| 809 | ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); |
| 810 | if (ret || !iov_iter_count(iter)) |
| 811 | goto done; |
| 812 | |
| 813 | ret = copy_to_iter(&veth, sizeof(veth), iter); |
| 814 | if (ret != sizeof(veth) || !iov_iter_count(iter)) |
| 815 | goto done; |
| 816 | } |
| 817 | |
| 818 | ret = skb_copy_datagram_iter(skb, vlan_offset, iter, |
| 819 | skb->len - vlan_offset); |
| 820 | |
| 821 | done: |
| 822 | return ret ? ret : total; |
| 823 | } |
| 824 | |
| 825 | static ssize_t tap_do_read(struct tap_queue *q, |
| 826 | struct iov_iter *to, |
| 827 | int noblock, struct sk_buff *skb) |
| 828 | { |
| 829 | DEFINE_WAIT(wait); |
| 830 | ssize_t ret = 0; |
| 831 | |
| 832 | if (!iov_iter_count(to)) { |
| 833 | kfree_skb(skb); |
| 834 | return 0; |
| 835 | } |
| 836 | |
| 837 | if (skb) |
| 838 | goto put; |
| 839 | |
| 840 | while (1) { |
| 841 | if (!noblock) |
| 842 | prepare_to_wait(sk_sleep(&q->sk), &wait, |
| 843 | TASK_INTERRUPTIBLE); |
| 844 | |
| 845 | /* Read frames from the queue */ |
| 846 | skb = ptr_ring_consume(&q->ring); |
| 847 | if (skb) |
| 848 | break; |
| 849 | if (noblock) { |
| 850 | ret = -EAGAIN; |
| 851 | break; |
| 852 | } |
| 853 | if (signal_pending(current)) { |
| 854 | ret = -ERESTARTSYS; |
| 855 | break; |
| 856 | } |
| 857 | /* Nothing to read, let's sleep */ |
| 858 | schedule(); |
| 859 | } |
| 860 | if (!noblock) |
| 861 | finish_wait(sk_sleep(&q->sk), &wait); |
| 862 | |
| 863 | put: |
| 864 | if (skb) { |
| 865 | ret = tap_put_user(q, skb, to); |
| 866 | if (unlikely(ret < 0)) |
| 867 | kfree_skb(skb); |
| 868 | else |
| 869 | consume_skb(skb); |
| 870 | } |
| 871 | return ret; |
| 872 | } |
| 873 | |
| 874 | static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| 875 | { |
| 876 | struct file *file = iocb->ki_filp; |
| 877 | struct tap_queue *q = file->private_data; |
| 878 | ssize_t len = iov_iter_count(to), ret; |
| 879 | |
| 880 | ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL); |
| 881 | ret = min_t(ssize_t, ret, len); |
| 882 | if (ret > 0) |
| 883 | iocb->ki_pos = ret; |
| 884 | return ret; |
| 885 | } |
| 886 | |
| 887 | static struct tap_dev *tap_get_tap_dev(struct tap_queue *q) |
| 888 | { |
| 889 | struct tap_dev *tap; |
| 890 | |
| 891 | ASSERT_RTNL(); |
| 892 | tap = rtnl_dereference(q->tap); |
| 893 | if (tap) |
| 894 | dev_hold(tap->dev); |
| 895 | |
| 896 | return tap; |
| 897 | } |
| 898 | |
| 899 | static void tap_put_tap_dev(struct tap_dev *tap) |
| 900 | { |
| 901 | dev_put(tap->dev); |
| 902 | } |
| 903 | |
| 904 | static int tap_ioctl_set_queue(struct file *file, unsigned int flags) |
| 905 | { |
| 906 | struct tap_queue *q = file->private_data; |
| 907 | struct tap_dev *tap; |
| 908 | int ret; |
| 909 | |
| 910 | tap = tap_get_tap_dev(q); |
| 911 | if (!tap) |
| 912 | return -EINVAL; |
| 913 | |
| 914 | if (flags & IFF_ATTACH_QUEUE) |
| 915 | ret = tap_enable_queue(tap, file, q); |
| 916 | else if (flags & IFF_DETACH_QUEUE) |
| 917 | ret = tap_disable_queue(q); |
| 918 | else |
| 919 | ret = -EINVAL; |
| 920 | |
| 921 | tap_put_tap_dev(tap); |
| 922 | return ret; |
| 923 | } |
| 924 | |
| 925 | static int set_offload(struct tap_queue *q, unsigned long arg) |
| 926 | { |
| 927 | struct tap_dev *tap; |
| 928 | netdev_features_t features; |
| 929 | netdev_features_t feature_mask = 0; |
| 930 | |
| 931 | tap = rtnl_dereference(q->tap); |
| 932 | if (!tap) |
| 933 | return -ENOLINK; |
| 934 | |
| 935 | features = tap->dev->features; |
| 936 | |
| 937 | if (arg & TUN_F_CSUM) { |
| 938 | feature_mask = NETIF_F_HW_CSUM; |
| 939 | |
| 940 | if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { |
| 941 | if (arg & TUN_F_TSO_ECN) |
| 942 | feature_mask |= NETIF_F_TSO_ECN; |
| 943 | if (arg & TUN_F_TSO4) |
| 944 | feature_mask |= NETIF_F_TSO; |
| 945 | if (arg & TUN_F_TSO6) |
| 946 | feature_mask |= NETIF_F_TSO6; |
| 947 | } |
| 948 | } |
| 949 | |
| 950 | /* tun/tap driver inverts the usage for TSO offloads, where |
| 951 | * setting the TSO bit means that the userspace wants to |
| 952 | * accept TSO frames and turning it off means that user space |
| 953 | * does not support TSO. |
| 954 | * For tap, we have to invert it to mean the same thing. |
| 955 | * When user space turns off TSO, we turn off GSO/LRO so that |
| 956 | * user-space will not receive TSO frames. |
| 957 | */ |
| 958 | if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6)) |
| 959 | features |= RX_OFFLOADS; |
| 960 | else |
| 961 | features &= ~RX_OFFLOADS; |
| 962 | |
| 963 | /* tap_features are the same as features on tun/tap and |
| 964 | * reflect user expectations. |
| 965 | */ |
| 966 | tap->tap_features = feature_mask; |
| 967 | if (tap->update_features) |
| 968 | tap->update_features(tap, features); |
| 969 | |
| 970 | return 0; |
| 971 | } |
| 972 | |
| 973 | /* |
| 974 | * provide compatibility with generic tun/tap interface |
| 975 | */ |
| 976 | static long tap_ioctl(struct file *file, unsigned int cmd, |
| 977 | unsigned long arg) |
| 978 | { |
| 979 | struct tap_queue *q = file->private_data; |
| 980 | struct tap_dev *tap; |
| 981 | void __user *argp = (void __user *)arg; |
| 982 | struct ifreq __user *ifr = argp; |
| 983 | unsigned int __user *up = argp; |
| 984 | unsigned short u; |
| 985 | int __user *sp = argp; |
| 986 | struct sockaddr sa; |
| 987 | int s; |
| 988 | int ret; |
| 989 | |
| 990 | switch (cmd) { |
| 991 | case TUNSETIFF: |
| 992 | /* ignore the name, just look at flags */ |
| 993 | if (get_user(u, &ifr->ifr_flags)) |
| 994 | return -EFAULT; |
| 995 | |
| 996 | ret = 0; |
| 997 | if ((u & ~TAP_IFFEATURES) != (IFF_NO_PI | IFF_TAP)) |
| 998 | ret = -EINVAL; |
| 999 | else |
| 1000 | q->flags = (q->flags & ~TAP_IFFEATURES) | u; |
| 1001 | |
| 1002 | return ret; |
| 1003 | |
| 1004 | case TUNGETIFF: |
| 1005 | rtnl_lock(); |
| 1006 | tap = tap_get_tap_dev(q); |
| 1007 | if (!tap) { |
| 1008 | rtnl_unlock(); |
| 1009 | return -ENOLINK; |
| 1010 | } |
| 1011 | |
| 1012 | ret = 0; |
| 1013 | u = q->flags; |
| 1014 | if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || |
| 1015 | put_user(u, &ifr->ifr_flags)) |
| 1016 | ret = -EFAULT; |
| 1017 | tap_put_tap_dev(tap); |
| 1018 | rtnl_unlock(); |
| 1019 | return ret; |
| 1020 | |
| 1021 | case TUNSETQUEUE: |
| 1022 | if (get_user(u, &ifr->ifr_flags)) |
| 1023 | return -EFAULT; |
| 1024 | rtnl_lock(); |
| 1025 | ret = tap_ioctl_set_queue(file, u); |
| 1026 | rtnl_unlock(); |
| 1027 | return ret; |
| 1028 | |
| 1029 | case TUNGETFEATURES: |
| 1030 | if (put_user(IFF_TAP | IFF_NO_PI | TAP_IFFEATURES, up)) |
| 1031 | return -EFAULT; |
| 1032 | return 0; |
| 1033 | |
| 1034 | case TUNSETSNDBUF: |
| 1035 | if (get_user(s, sp)) |
| 1036 | return -EFAULT; |
| 1037 | if (s <= 0) |
| 1038 | return -EINVAL; |
| 1039 | |
| 1040 | q->sk.sk_sndbuf = s; |
| 1041 | return 0; |
| 1042 | |
| 1043 | case TUNGETVNETHDRSZ: |
| 1044 | s = q->vnet_hdr_sz; |
| 1045 | if (put_user(s, sp)) |
| 1046 | return -EFAULT; |
| 1047 | return 0; |
| 1048 | |
| 1049 | case TUNSETVNETHDRSZ: |
| 1050 | if (get_user(s, sp)) |
| 1051 | return -EFAULT; |
| 1052 | if (s < (int)sizeof(struct virtio_net_hdr)) |
| 1053 | return -EINVAL; |
| 1054 | |
| 1055 | q->vnet_hdr_sz = s; |
| 1056 | return 0; |
| 1057 | |
| 1058 | case TUNGETVNETLE: |
| 1059 | s = !!(q->flags & TAP_VNET_LE); |
| 1060 | if (put_user(s, sp)) |
| 1061 | return -EFAULT; |
| 1062 | return 0; |
| 1063 | |
| 1064 | case TUNSETVNETLE: |
| 1065 | if (get_user(s, sp)) |
| 1066 | return -EFAULT; |
| 1067 | if (s) |
| 1068 | q->flags |= TAP_VNET_LE; |
| 1069 | else |
| 1070 | q->flags &= ~TAP_VNET_LE; |
| 1071 | return 0; |
| 1072 | |
| 1073 | case TUNGETVNETBE: |
| 1074 | return tap_get_vnet_be(q, sp); |
| 1075 | |
| 1076 | case TUNSETVNETBE: |
| 1077 | return tap_set_vnet_be(q, sp); |
| 1078 | |
| 1079 | case TUNSETOFFLOAD: |
| 1080 | /* let the user check for future flags */ |
| 1081 | if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | |
| 1082 | TUN_F_TSO_ECN | TUN_F_UFO)) |
| 1083 | return -EINVAL; |
| 1084 | |
| 1085 | rtnl_lock(); |
| 1086 | ret = set_offload(q, arg); |
| 1087 | rtnl_unlock(); |
| 1088 | return ret; |
| 1089 | |
| 1090 | case SIOCGIFHWADDR: |
| 1091 | rtnl_lock(); |
| 1092 | tap = tap_get_tap_dev(q); |
| 1093 | if (!tap) { |
| 1094 | rtnl_unlock(); |
| 1095 | return -ENOLINK; |
| 1096 | } |
| 1097 | ret = 0; |
Googler | b48fa91 | 2023-03-17 12:40:29 +0530 | [diff] [blame^] | 1098 | u = tap->dev->type; |
Googler | 9398cc3 | 2022-12-02 17:21:52 +0800 | [diff] [blame] | 1099 | if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || |
Googler | b48fa91 | 2023-03-17 12:40:29 +0530 | [diff] [blame^] | 1100 | copy_to_user(&ifr->ifr_hwaddr.sa_data, tap->dev->dev_addr, ETH_ALEN) || |
| 1101 | put_user(u, &ifr->ifr_hwaddr.sa_family)) |
Googler | 9398cc3 | 2022-12-02 17:21:52 +0800 | [diff] [blame] | 1102 | ret = -EFAULT; |
| 1103 | tap_put_tap_dev(tap); |
| 1104 | rtnl_unlock(); |
| 1105 | return ret; |
| 1106 | |
| 1107 | case SIOCSIFHWADDR: |
| 1108 | if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa))) |
| 1109 | return -EFAULT; |
| 1110 | rtnl_lock(); |
| 1111 | tap = tap_get_tap_dev(q); |
| 1112 | if (!tap) { |
| 1113 | rtnl_unlock(); |
| 1114 | return -ENOLINK; |
| 1115 | } |
Googler | b48fa91 | 2023-03-17 12:40:29 +0530 | [diff] [blame^] | 1116 | ret = dev_set_mac_address(tap->dev, &sa, NULL); |
Googler | 9398cc3 | 2022-12-02 17:21:52 +0800 | [diff] [blame] | 1117 | tap_put_tap_dev(tap); |
| 1118 | rtnl_unlock(); |
| 1119 | return ret; |
| 1120 | |
| 1121 | default: |
| 1122 | return -EINVAL; |
| 1123 | } |
| 1124 | } |
| 1125 | |
| 1126 | #ifdef CONFIG_COMPAT |
| 1127 | static long tap_compat_ioctl(struct file *file, unsigned int cmd, |
| 1128 | unsigned long arg) |
| 1129 | { |
| 1130 | return tap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); |
| 1131 | } |
| 1132 | #endif |
| 1133 | |
| 1134 | static const struct file_operations tap_fops = { |
| 1135 | .owner = THIS_MODULE, |
| 1136 | .open = tap_open, |
| 1137 | .release = tap_release, |
| 1138 | .read_iter = tap_read_iter, |
| 1139 | .write_iter = tap_write_iter, |
| 1140 | .poll = tap_poll, |
| 1141 | .llseek = no_llseek, |
| 1142 | .unlocked_ioctl = tap_ioctl, |
| 1143 | #ifdef CONFIG_COMPAT |
| 1144 | .compat_ioctl = tap_compat_ioctl, |
| 1145 | #endif |
| 1146 | }; |
| 1147 | |
| 1148 | static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) |
| 1149 | { |
| 1150 | struct tun_xdp_hdr *hdr = xdp->data_hard_start; |
| 1151 | struct virtio_net_hdr *gso = &hdr->gso; |
| 1152 | int buflen = hdr->buflen; |
| 1153 | int vnet_hdr_len = 0; |
| 1154 | struct tap_dev *tap; |
| 1155 | struct sk_buff *skb; |
| 1156 | int err, depth; |
| 1157 | |
| 1158 | if (q->flags & IFF_VNET_HDR) |
| 1159 | vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); |
| 1160 | |
| 1161 | skb = build_skb(xdp->data_hard_start, buflen); |
| 1162 | if (!skb) { |
| 1163 | err = -ENOMEM; |
| 1164 | goto err; |
| 1165 | } |
| 1166 | |
| 1167 | skb_reserve(skb, xdp->data - xdp->data_hard_start); |
| 1168 | skb_put(skb, xdp->data_end - xdp->data); |
| 1169 | |
| 1170 | skb_set_network_header(skb, ETH_HLEN); |
| 1171 | skb_reset_mac_header(skb); |
| 1172 | skb->protocol = eth_hdr(skb)->h_proto; |
| 1173 | |
| 1174 | if (vnet_hdr_len) { |
| 1175 | err = virtio_net_hdr_to_skb(skb, gso, tap_is_little_endian(q)); |
| 1176 | if (err) |
| 1177 | goto err_kfree; |
| 1178 | } |
| 1179 | |
| 1180 | /* Move network header to the right position for VLAN tagged packets */ |
| 1181 | if ((skb->protocol == htons(ETH_P_8021Q) || |
| 1182 | skb->protocol == htons(ETH_P_8021AD)) && |
| 1183 | __vlan_get_protocol(skb, skb->protocol, &depth) != 0) |
| 1184 | skb_set_network_header(skb, depth); |
| 1185 | |
| 1186 | rcu_read_lock(); |
| 1187 | tap = rcu_dereference(q->tap); |
| 1188 | if (tap) { |
| 1189 | skb->dev = tap->dev; |
| 1190 | skb_probe_transport_header(skb); |
| 1191 | dev_queue_xmit(skb); |
| 1192 | } else { |
| 1193 | kfree_skb(skb); |
| 1194 | } |
| 1195 | rcu_read_unlock(); |
| 1196 | |
| 1197 | return 0; |
| 1198 | |
| 1199 | err_kfree: |
| 1200 | kfree_skb(skb); |
| 1201 | err: |
| 1202 | rcu_read_lock(); |
| 1203 | tap = rcu_dereference(q->tap); |
| 1204 | if (tap && tap->count_tx_dropped) |
| 1205 | tap->count_tx_dropped(tap); |
| 1206 | rcu_read_unlock(); |
| 1207 | return err; |
| 1208 | } |
| 1209 | |
| 1210 | static int tap_sendmsg(struct socket *sock, struct msghdr *m, |
| 1211 | size_t total_len) |
| 1212 | { |
| 1213 | struct tap_queue *q = container_of(sock, struct tap_queue, sock); |
| 1214 | struct tun_msg_ctl *ctl = m->msg_control; |
| 1215 | struct xdp_buff *xdp; |
| 1216 | int i; |
| 1217 | |
Googler | b48fa91 | 2023-03-17 12:40:29 +0530 | [diff] [blame^] | 1218 | if (ctl && (ctl->type == TUN_MSG_PTR)) { |
Googler | 9398cc3 | 2022-12-02 17:21:52 +0800 | [diff] [blame] | 1219 | for (i = 0; i < ctl->num; i++) { |
| 1220 | xdp = &((struct xdp_buff *)ctl->ptr)[i]; |
| 1221 | tap_get_user_xdp(q, xdp); |
| 1222 | } |
| 1223 | return 0; |
| 1224 | } |
| 1225 | |
| 1226 | return tap_get_user(q, ctl ? ctl->ptr : NULL, &m->msg_iter, |
| 1227 | m->msg_flags & MSG_DONTWAIT); |
| 1228 | } |
| 1229 | |
| 1230 | static int tap_recvmsg(struct socket *sock, struct msghdr *m, |
| 1231 | size_t total_len, int flags) |
| 1232 | { |
| 1233 | struct tap_queue *q = container_of(sock, struct tap_queue, sock); |
| 1234 | struct sk_buff *skb = m->msg_control; |
| 1235 | int ret; |
| 1236 | if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) { |
| 1237 | kfree_skb(skb); |
| 1238 | return -EINVAL; |
| 1239 | } |
| 1240 | ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb); |
| 1241 | if (ret > total_len) { |
| 1242 | m->msg_flags |= MSG_TRUNC; |
| 1243 | ret = flags & MSG_TRUNC ? ret : total_len; |
| 1244 | } |
| 1245 | return ret; |
| 1246 | } |
| 1247 | |
| 1248 | static int tap_peek_len(struct socket *sock) |
| 1249 | { |
| 1250 | struct tap_queue *q = container_of(sock, struct tap_queue, |
| 1251 | sock); |
| 1252 | return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag); |
| 1253 | } |
| 1254 | |
| 1255 | /* Ops structure to mimic raw sockets with tun */ |
| 1256 | static const struct proto_ops tap_socket_ops = { |
| 1257 | .sendmsg = tap_sendmsg, |
| 1258 | .recvmsg = tap_recvmsg, |
| 1259 | .peek_len = tap_peek_len, |
| 1260 | }; |
| 1261 | |
| 1262 | /* Get an underlying socket object from tun file. Returns error unless file is |
| 1263 | * attached to a device. The returned object works like a packet socket, it |
| 1264 | * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for |
| 1265 | * holding a reference to the file for as long as the socket is in use. */ |
| 1266 | struct socket *tap_get_socket(struct file *file) |
| 1267 | { |
| 1268 | struct tap_queue *q; |
| 1269 | if (file->f_op != &tap_fops) |
| 1270 | return ERR_PTR(-EINVAL); |
| 1271 | q = file->private_data; |
| 1272 | if (!q) |
| 1273 | return ERR_PTR(-EBADFD); |
| 1274 | return &q->sock; |
| 1275 | } |
| 1276 | EXPORT_SYMBOL_GPL(tap_get_socket); |
| 1277 | |
| 1278 | struct ptr_ring *tap_get_ptr_ring(struct file *file) |
| 1279 | { |
| 1280 | struct tap_queue *q; |
| 1281 | |
| 1282 | if (file->f_op != &tap_fops) |
| 1283 | return ERR_PTR(-EINVAL); |
| 1284 | q = file->private_data; |
| 1285 | if (!q) |
| 1286 | return ERR_PTR(-EBADFD); |
| 1287 | return &q->ring; |
| 1288 | } |
| 1289 | EXPORT_SYMBOL_GPL(tap_get_ptr_ring); |
| 1290 | |
| 1291 | int tap_queue_resize(struct tap_dev *tap) |
| 1292 | { |
| 1293 | struct net_device *dev = tap->dev; |
| 1294 | struct tap_queue *q; |
| 1295 | struct ptr_ring **rings; |
| 1296 | int n = tap->numqueues; |
| 1297 | int ret, i = 0; |
| 1298 | |
| 1299 | rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL); |
| 1300 | if (!rings) |
| 1301 | return -ENOMEM; |
| 1302 | |
| 1303 | list_for_each_entry(q, &tap->queue_list, next) |
| 1304 | rings[i++] = &q->ring; |
| 1305 | |
| 1306 | ret = ptr_ring_resize_multiple(rings, n, |
| 1307 | dev->tx_queue_len, GFP_KERNEL, |
| 1308 | __skb_array_destroy_skb); |
| 1309 | |
| 1310 | kfree(rings); |
| 1311 | return ret; |
| 1312 | } |
| 1313 | EXPORT_SYMBOL_GPL(tap_queue_resize); |
| 1314 | |
| 1315 | static int tap_list_add(dev_t major, const char *device_name) |
| 1316 | { |
| 1317 | struct major_info *tap_major; |
| 1318 | |
| 1319 | tap_major = kzalloc(sizeof(*tap_major), GFP_ATOMIC); |
| 1320 | if (!tap_major) |
| 1321 | return -ENOMEM; |
| 1322 | |
| 1323 | tap_major->major = MAJOR(major); |
| 1324 | |
| 1325 | idr_init(&tap_major->minor_idr); |
| 1326 | spin_lock_init(&tap_major->minor_lock); |
| 1327 | |
| 1328 | tap_major->device_name = device_name; |
| 1329 | |
| 1330 | list_add_tail_rcu(&tap_major->next, &major_list); |
| 1331 | return 0; |
| 1332 | } |
| 1333 | |
| 1334 | int tap_create_cdev(struct cdev *tap_cdev, dev_t *tap_major, |
| 1335 | const char *device_name, struct module *module) |
| 1336 | { |
| 1337 | int err; |
| 1338 | |
| 1339 | err = alloc_chrdev_region(tap_major, 0, TAP_NUM_DEVS, device_name); |
| 1340 | if (err) |
| 1341 | goto out1; |
| 1342 | |
| 1343 | cdev_init(tap_cdev, &tap_fops); |
| 1344 | tap_cdev->owner = module; |
| 1345 | err = cdev_add(tap_cdev, *tap_major, TAP_NUM_DEVS); |
| 1346 | if (err) |
| 1347 | goto out2; |
| 1348 | |
| 1349 | err = tap_list_add(*tap_major, device_name); |
| 1350 | if (err) |
| 1351 | goto out3; |
| 1352 | |
| 1353 | return 0; |
| 1354 | |
| 1355 | out3: |
| 1356 | cdev_del(tap_cdev); |
| 1357 | out2: |
| 1358 | unregister_chrdev_region(*tap_major, TAP_NUM_DEVS); |
| 1359 | out1: |
| 1360 | return err; |
| 1361 | } |
| 1362 | EXPORT_SYMBOL_GPL(tap_create_cdev); |
| 1363 | |
| 1364 | void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev) |
| 1365 | { |
| 1366 | struct major_info *tap_major, *tmp; |
| 1367 | |
| 1368 | cdev_del(tap_cdev); |
| 1369 | unregister_chrdev_region(major, TAP_NUM_DEVS); |
| 1370 | list_for_each_entry_safe(tap_major, tmp, &major_list, next) { |
| 1371 | if (tap_major->major == MAJOR(major)) { |
| 1372 | idr_destroy(&tap_major->minor_idr); |
| 1373 | list_del_rcu(&tap_major->next); |
| 1374 | kfree_rcu(tap_major, rcu); |
| 1375 | } |
| 1376 | } |
| 1377 | } |
| 1378 | EXPORT_SYMBOL_GPL(tap_destroy_cdev); |
| 1379 | |
| 1380 | MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); |
| 1381 | MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>"); |
| 1382 | MODULE_LICENSE("GPL"); |