xref: /openbmc/linux/net/xdp/xsk.c (revision b143e19d)
1 // SPDX-License-Identifier: GPL-2.0
2 /* XDP sockets
3  *
4  * AF_XDP sockets allows a channel between XDP programs and userspace
5  * applications.
6  * Copyright(c) 2018 Intel Corporation.
7  *
8  * Author(s): Björn Töpel <bjorn.topel@intel.com>
9  *	      Magnus Karlsson <magnus.karlsson@intel.com>
10  */
11 
12 #define pr_fmt(fmt) "AF_XDP: %s: " fmt, __func__
13 
14 #include <linux/if_xdp.h>
15 #include <linux/init.h>
16 #include <linux/sched/mm.h>
17 #include <linux/sched/signal.h>
18 #include <linux/sched/task.h>
19 #include <linux/socket.h>
20 #include <linux/file.h>
21 #include <linux/uaccess.h>
22 #include <linux/net.h>
23 #include <linux/netdevice.h>
24 #include <linux/rculist.h>
25 #include <linux/vmalloc.h>
26 #include <net/xdp_sock_drv.h>
27 #include <net/busy_poll.h>
28 #include <net/netdev_rx_queue.h>
29 #include <net/xdp.h>
30 
31 #include "xsk_queue.h"
32 #include "xdp_umem.h"
33 #include "xsk.h"
34 
35 #define TX_BATCH_SIZE 32
36 
37 static DEFINE_PER_CPU(struct list_head, xskmap_flush_list);
38 
xsk_set_rx_need_wakeup(struct xsk_buff_pool * pool)39 void xsk_set_rx_need_wakeup(struct xsk_buff_pool *pool)
40 {
41 	if (pool->cached_need_wakeup & XDP_WAKEUP_RX)
42 		return;
43 
44 	pool->fq->ring->flags |= XDP_RING_NEED_WAKEUP;
45 	pool->cached_need_wakeup |= XDP_WAKEUP_RX;
46 }
47 EXPORT_SYMBOL(xsk_set_rx_need_wakeup);
48 
xsk_set_tx_need_wakeup(struct xsk_buff_pool * pool)49 void xsk_set_tx_need_wakeup(struct xsk_buff_pool *pool)
50 {
51 	struct xdp_sock *xs;
52 
53 	if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
54 		return;
55 
56 	rcu_read_lock();
57 	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
58 		xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
59 	}
60 	rcu_read_unlock();
61 
62 	pool->cached_need_wakeup |= XDP_WAKEUP_TX;
63 }
64 EXPORT_SYMBOL(xsk_set_tx_need_wakeup);
65 
xsk_clear_rx_need_wakeup(struct xsk_buff_pool * pool)66 void xsk_clear_rx_need_wakeup(struct xsk_buff_pool *pool)
67 {
68 	if (!(pool->cached_need_wakeup & XDP_WAKEUP_RX))
69 		return;
70 
71 	pool->fq->ring->flags &= ~XDP_RING_NEED_WAKEUP;
72 	pool->cached_need_wakeup &= ~XDP_WAKEUP_RX;
73 }
74 EXPORT_SYMBOL(xsk_clear_rx_need_wakeup);
75 
xsk_clear_tx_need_wakeup(struct xsk_buff_pool * pool)76 void xsk_clear_tx_need_wakeup(struct xsk_buff_pool *pool)
77 {
78 	struct xdp_sock *xs;
79 
80 	if (!(pool->cached_need_wakeup & XDP_WAKEUP_TX))
81 		return;
82 
83 	rcu_read_lock();
84 	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
85 		xs->tx->ring->flags &= ~XDP_RING_NEED_WAKEUP;
86 	}
87 	rcu_read_unlock();
88 
89 	pool->cached_need_wakeup &= ~XDP_WAKEUP_TX;
90 }
91 EXPORT_SYMBOL(xsk_clear_tx_need_wakeup);
92 
xsk_uses_need_wakeup(struct xsk_buff_pool * pool)93 bool xsk_uses_need_wakeup(struct xsk_buff_pool *pool)
94 {
95 	return pool->uses_need_wakeup;
96 }
97 EXPORT_SYMBOL(xsk_uses_need_wakeup);
98 
xsk_get_pool_from_qid(struct net_device * dev,u16 queue_id)99 struct xsk_buff_pool *xsk_get_pool_from_qid(struct net_device *dev,
100 					    u16 queue_id)
101 {
102 	if (queue_id < dev->real_num_rx_queues)
103 		return dev->_rx[queue_id].pool;
104 	if (queue_id < dev->real_num_tx_queues)
105 		return dev->_tx[queue_id].pool;
106 
107 	return NULL;
108 }
109 EXPORT_SYMBOL(xsk_get_pool_from_qid);
110 
xsk_clear_pool_at_qid(struct net_device * dev,u16 queue_id)111 void xsk_clear_pool_at_qid(struct net_device *dev, u16 queue_id)
112 {
113 	if (queue_id < dev->num_rx_queues)
114 		dev->_rx[queue_id].pool = NULL;
115 	if (queue_id < dev->num_tx_queues)
116 		dev->_tx[queue_id].pool = NULL;
117 }
118 
119 /* The buffer pool is stored both in the _rx struct and the _tx struct as we do
120  * not know if the device has more tx queues than rx, or the opposite.
121  * This might also change during run time.
122  */
xsk_reg_pool_at_qid(struct net_device * dev,struct xsk_buff_pool * pool,u16 queue_id)123 int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
124 			u16 queue_id)
125 {
126 	if (queue_id >= max_t(unsigned int,
127 			      dev->real_num_rx_queues,
128 			      dev->real_num_tx_queues))
129 		return -EINVAL;
130 
131 	if (queue_id < dev->real_num_rx_queues)
132 		dev->_rx[queue_id].pool = pool;
133 	if (queue_id < dev->real_num_tx_queues)
134 		dev->_tx[queue_id].pool = pool;
135 
136 	return 0;
137 }
138 
__xsk_rcv_zc(struct xdp_sock * xs,struct xdp_buff_xsk * xskb,u32 len,u32 flags)139 static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len,
140 			u32 flags)
141 {
142 	u64 addr;
143 	int err;
144 
145 	addr = xp_get_handle(xskb);
146 	err = xskq_prod_reserve_desc(xs->rx, addr, len, flags);
147 	if (err) {
148 		xs->rx_queue_full++;
149 		return err;
150 	}
151 
152 	xp_release(xskb);
153 	return 0;
154 }
155 
xsk_rcv_zc(struct xdp_sock * xs,struct xdp_buff * xdp,u32 len)156 static int xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
157 {
158 	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
159 	u32 frags = xdp_buff_has_frags(xdp);
160 	struct xdp_buff_xsk *pos, *tmp;
161 	struct list_head *xskb_list;
162 	u32 contd = 0;
163 	int err;
164 
165 	if (frags)
166 		contd = XDP_PKT_CONTD;
167 
168 	err = __xsk_rcv_zc(xs, xskb, len, contd);
169 	if (err)
170 		goto err;
171 	if (likely(!frags))
172 		return 0;
173 
174 	xskb_list = &xskb->pool->xskb_list;
175 	list_for_each_entry_safe(pos, tmp, xskb_list, xskb_list_node) {
176 		if (list_is_singular(xskb_list))
177 			contd = 0;
178 		len = pos->xdp.data_end - pos->xdp.data;
179 		err = __xsk_rcv_zc(xs, pos, len, contd);
180 		if (err)
181 			goto err;
182 		list_del(&pos->xskb_list_node);
183 	}
184 
185 	return 0;
186 err:
187 	xsk_buff_free(xdp);
188 	return err;
189 }
190 
xsk_copy_xdp_start(struct xdp_buff * from)191 static void *xsk_copy_xdp_start(struct xdp_buff *from)
192 {
193 	if (unlikely(xdp_data_meta_unsupported(from)))
194 		return from->data;
195 	else
196 		return from->data_meta;
197 }
198 
xsk_copy_xdp(void * to,void ** from,u32 to_len,u32 * from_len,skb_frag_t ** frag,u32 rem)199 static u32 xsk_copy_xdp(void *to, void **from, u32 to_len,
200 			u32 *from_len, skb_frag_t **frag, u32 rem)
201 {
202 	u32 copied = 0;
203 
204 	while (1) {
205 		u32 copy_len = min_t(u32, *from_len, to_len);
206 
207 		memcpy(to, *from, copy_len);
208 		copied += copy_len;
209 		if (rem == copied)
210 			return copied;
211 
212 		if (*from_len == copy_len) {
213 			*from = skb_frag_address(*frag);
214 			*from_len = skb_frag_size((*frag)++);
215 		} else {
216 			*from += copy_len;
217 			*from_len -= copy_len;
218 		}
219 		if (to_len == copy_len)
220 			return copied;
221 
222 		to_len -= copy_len;
223 		to += copy_len;
224 	}
225 }
226 
__xsk_rcv(struct xdp_sock * xs,struct xdp_buff * xdp,u32 len)227 static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
228 {
229 	u32 frame_size = xsk_pool_get_rx_frame_size(xs->pool);
230 	void *copy_from = xsk_copy_xdp_start(xdp), *copy_to;
231 	u32 from_len, meta_len, rem, num_desc;
232 	struct xdp_buff_xsk *xskb;
233 	struct xdp_buff *xsk_xdp;
234 	skb_frag_t *frag;
235 
236 	from_len = xdp->data_end - copy_from;
237 	meta_len = xdp->data - copy_from;
238 	rem = len + meta_len;
239 
240 	if (len <= frame_size && !xdp_buff_has_frags(xdp)) {
241 		int err;
242 
243 		xsk_xdp = xsk_buff_alloc(xs->pool);
244 		if (!xsk_xdp) {
245 			xs->rx_dropped++;
246 			return -ENOMEM;
247 		}
248 		memcpy(xsk_xdp->data - meta_len, copy_from, rem);
249 		xskb = container_of(xsk_xdp, struct xdp_buff_xsk, xdp);
250 		err = __xsk_rcv_zc(xs, xskb, len, 0);
251 		if (err) {
252 			xsk_buff_free(xsk_xdp);
253 			return err;
254 		}
255 
256 		return 0;
257 	}
258 
259 	num_desc = (len - 1) / frame_size + 1;
260 
261 	if (!xsk_buff_can_alloc(xs->pool, num_desc)) {
262 		xs->rx_dropped++;
263 		return -ENOMEM;
264 	}
265 	if (xskq_prod_nb_free(xs->rx, num_desc) < num_desc) {
266 		xs->rx_queue_full++;
267 		return -ENOBUFS;
268 	}
269 
270 	if (xdp_buff_has_frags(xdp)) {
271 		struct skb_shared_info *sinfo;
272 
273 		sinfo = xdp_get_shared_info_from_buff(xdp);
274 		frag =  &sinfo->frags[0];
275 	}
276 
277 	do {
278 		u32 to_len = frame_size + meta_len;
279 		u32 copied;
280 
281 		xsk_xdp = xsk_buff_alloc(xs->pool);
282 		copy_to = xsk_xdp->data - meta_len;
283 
284 		copied = xsk_copy_xdp(copy_to, &copy_from, to_len, &from_len, &frag, rem);
285 		rem -= copied;
286 
287 		xskb = container_of(xsk_xdp, struct xdp_buff_xsk, xdp);
288 		__xsk_rcv_zc(xs, xskb, copied - meta_len, rem ? XDP_PKT_CONTD : 0);
289 		meta_len = 0;
290 	} while (rem);
291 
292 	return 0;
293 }
294 
xsk_tx_writeable(struct xdp_sock * xs)295 static bool xsk_tx_writeable(struct xdp_sock *xs)
296 {
297 	if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2)
298 		return false;
299 
300 	return true;
301 }
302 
xsk_is_bound(struct xdp_sock * xs)303 static bool xsk_is_bound(struct xdp_sock *xs)
304 {
305 	if (READ_ONCE(xs->state) == XSK_BOUND) {
306 		/* Matches smp_wmb() in bind(). */
307 		smp_rmb();
308 		return true;
309 	}
310 	return false;
311 }
312 
xsk_rcv_check(struct xdp_sock * xs,struct xdp_buff * xdp,u32 len)313 static int xsk_rcv_check(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len)
314 {
315 	if (!xsk_is_bound(xs))
316 		return -ENXIO;
317 
318 	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
319 		return -EINVAL;
320 
321 	if (len > xsk_pool_get_rx_frame_size(xs->pool) && !xs->sg) {
322 		xs->rx_dropped++;
323 		return -ENOSPC;
324 	}
325 
326 	sk_mark_napi_id_once_xdp(&xs->sk, xdp);
327 	return 0;
328 }
329 
xsk_flush(struct xdp_sock * xs)330 static void xsk_flush(struct xdp_sock *xs)
331 {
332 	xskq_prod_submit(xs->rx);
333 	__xskq_cons_release(xs->pool->fq);
334 	sock_def_readable(&xs->sk);
335 }
336 
xsk_generic_rcv(struct xdp_sock * xs,struct xdp_buff * xdp)337 int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
338 {
339 	u32 len = xdp_get_buff_len(xdp);
340 	int err;
341 
342 	spin_lock_bh(&xs->rx_lock);
343 	err = xsk_rcv_check(xs, xdp, len);
344 	if (!err) {
345 		err = __xsk_rcv(xs, xdp, len);
346 		xsk_flush(xs);
347 	}
348 	spin_unlock_bh(&xs->rx_lock);
349 	return err;
350 }
351 
xsk_rcv(struct xdp_sock * xs,struct xdp_buff * xdp)352 static int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
353 {
354 	u32 len = xdp_get_buff_len(xdp);
355 	int err;
356 
357 	err = xsk_rcv_check(xs, xdp, len);
358 	if (err)
359 		return err;
360 
361 	if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) {
362 		len = xdp->data_end - xdp->data;
363 		return xsk_rcv_zc(xs, xdp, len);
364 	}
365 
366 	err = __xsk_rcv(xs, xdp, len);
367 	if (!err)
368 		xdp_return_buff(xdp);
369 	return err;
370 }
371 
__xsk_map_redirect(struct xdp_sock * xs,struct xdp_buff * xdp)372 int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
373 {
374 	struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
375 	int err;
376 
377 	err = xsk_rcv(xs, xdp);
378 	if (err)
379 		return err;
380 
381 	if (!xs->flush_node.prev)
382 		list_add(&xs->flush_node, flush_list);
383 
384 	return 0;
385 }
386 
__xsk_map_flush(void)387 void __xsk_map_flush(void)
388 {
389 	struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
390 	struct xdp_sock *xs, *tmp;
391 
392 	list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
393 		xsk_flush(xs);
394 		__list_del_clearprev(&xs->flush_node);
395 	}
396 }
397 
xsk_tx_completed(struct xsk_buff_pool * pool,u32 nb_entries)398 void xsk_tx_completed(struct xsk_buff_pool *pool, u32 nb_entries)
399 {
400 	xskq_prod_submit_n(pool->cq, nb_entries);
401 }
402 EXPORT_SYMBOL(xsk_tx_completed);
403 
xsk_tx_release(struct xsk_buff_pool * pool)404 void xsk_tx_release(struct xsk_buff_pool *pool)
405 {
406 	struct xdp_sock *xs;
407 
408 	rcu_read_lock();
409 	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
410 		__xskq_cons_release(xs->tx);
411 		if (xsk_tx_writeable(xs))
412 			xs->sk.sk_write_space(&xs->sk);
413 	}
414 	rcu_read_unlock();
415 }
416 EXPORT_SYMBOL(xsk_tx_release);
417 
xsk_tx_peek_desc(struct xsk_buff_pool * pool,struct xdp_desc * desc)418 bool xsk_tx_peek_desc(struct xsk_buff_pool *pool, struct xdp_desc *desc)
419 {
420 	struct xdp_sock *xs;
421 
422 	rcu_read_lock();
423 	list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) {
424 		if (!xskq_cons_peek_desc(xs->tx, desc, pool)) {
425 			if (xskq_has_descs(xs->tx))
426 				xskq_cons_release(xs->tx);
427 			continue;
428 		}
429 
430 		/* This is the backpressure mechanism for the Tx path.
431 		 * Reserve space in the completion queue and only proceed
432 		 * if there is space in it. This avoids having to implement
433 		 * any buffering in the Tx path.
434 		 */
435 		if (xskq_prod_reserve_addr(pool->cq, desc->addr))
436 			goto out;
437 
438 		xskq_cons_release(xs->tx);
439 		rcu_read_unlock();
440 		return true;
441 	}
442 
443 out:
444 	rcu_read_unlock();
445 	return false;
446 }
447 EXPORT_SYMBOL(xsk_tx_peek_desc);
448 
xsk_tx_peek_release_fallback(struct xsk_buff_pool * pool,u32 max_entries)449 static u32 xsk_tx_peek_release_fallback(struct xsk_buff_pool *pool, u32 max_entries)
450 {
451 	struct xdp_desc *descs = pool->tx_descs;
452 	u32 nb_pkts = 0;
453 
454 	while (nb_pkts < max_entries && xsk_tx_peek_desc(pool, &descs[nb_pkts]))
455 		nb_pkts++;
456 
457 	xsk_tx_release(pool);
458 	return nb_pkts;
459 }
460 
xsk_tx_peek_release_desc_batch(struct xsk_buff_pool * pool,u32 nb_pkts)461 u32 xsk_tx_peek_release_desc_batch(struct xsk_buff_pool *pool, u32 nb_pkts)
462 {
463 	struct xdp_sock *xs;
464 
465 	rcu_read_lock();
466 	if (!list_is_singular(&pool->xsk_tx_list)) {
467 		/* Fallback to the non-batched version */
468 		rcu_read_unlock();
469 		return xsk_tx_peek_release_fallback(pool, nb_pkts);
470 	}
471 
472 	xs = list_first_or_null_rcu(&pool->xsk_tx_list, struct xdp_sock, tx_list);
473 	if (!xs) {
474 		nb_pkts = 0;
475 		goto out;
476 	}
477 
478 	nb_pkts = xskq_cons_nb_entries(xs->tx, nb_pkts);
479 
480 	/* This is the backpressure mechanism for the Tx path. Try to
481 	 * reserve space in the completion queue for all packets, but
482 	 * if there are fewer slots available, just process that many
483 	 * packets. This avoids having to implement any buffering in
484 	 * the Tx path.
485 	 */
486 	nb_pkts = xskq_prod_nb_free(pool->cq, nb_pkts);
487 	if (!nb_pkts)
488 		goto out;
489 
490 	nb_pkts = xskq_cons_read_desc_batch(xs->tx, pool, nb_pkts);
491 	if (!nb_pkts) {
492 		xs->tx->queue_empty_descs++;
493 		goto out;
494 	}
495 
496 	__xskq_cons_release(xs->tx);
497 	xskq_prod_write_addr_batch(pool->cq, pool->tx_descs, nb_pkts);
498 	xs->sk.sk_write_space(&xs->sk);
499 
500 out:
501 	rcu_read_unlock();
502 	return nb_pkts;
503 }
504 EXPORT_SYMBOL(xsk_tx_peek_release_desc_batch);
505 
xsk_wakeup(struct xdp_sock * xs,u8 flags)506 static int xsk_wakeup(struct xdp_sock *xs, u8 flags)
507 {
508 	struct net_device *dev = xs->dev;
509 
510 	return dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, flags);
511 }
512 
xsk_cq_reserve_addr_locked(struct xdp_sock * xs,u64 addr)513 static int xsk_cq_reserve_addr_locked(struct xdp_sock *xs, u64 addr)
514 {
515 	unsigned long flags;
516 	int ret;
517 
518 	spin_lock_irqsave(&xs->pool->cq_lock, flags);
519 	ret = xskq_prod_reserve_addr(xs->pool->cq, addr);
520 	spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
521 
522 	return ret;
523 }
524 
xsk_cq_submit_locked(struct xdp_sock * xs,u32 n)525 static void xsk_cq_submit_locked(struct xdp_sock *xs, u32 n)
526 {
527 	unsigned long flags;
528 
529 	spin_lock_irqsave(&xs->pool->cq_lock, flags);
530 	xskq_prod_submit_n(xs->pool->cq, n);
531 	spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
532 }
533 
xsk_cq_cancel_locked(struct xdp_sock * xs,u32 n)534 static void xsk_cq_cancel_locked(struct xdp_sock *xs, u32 n)
535 {
536 	unsigned long flags;
537 
538 	spin_lock_irqsave(&xs->pool->cq_lock, flags);
539 	xskq_prod_cancel_n(xs->pool->cq, n);
540 	spin_unlock_irqrestore(&xs->pool->cq_lock, flags);
541 }
542 
xsk_get_num_desc(struct sk_buff * skb)543 static u32 xsk_get_num_desc(struct sk_buff *skb)
544 {
545 	return skb ? (long)skb_shinfo(skb)->destructor_arg : 0;
546 }
547 
xsk_destruct_skb(struct sk_buff * skb)548 static void xsk_destruct_skb(struct sk_buff *skb)
549 {
550 	xsk_cq_submit_locked(xdp_sk(skb->sk), xsk_get_num_desc(skb));
551 	sock_wfree(skb);
552 }
553 
xsk_set_destructor_arg(struct sk_buff * skb)554 static void xsk_set_destructor_arg(struct sk_buff *skb)
555 {
556 	long num = xsk_get_num_desc(xdp_sk(skb->sk)->skb) + 1;
557 
558 	skb_shinfo(skb)->destructor_arg = (void *)num;
559 }
560 
xsk_consume_skb(struct sk_buff * skb)561 static void xsk_consume_skb(struct sk_buff *skb)
562 {
563 	struct xdp_sock *xs = xdp_sk(skb->sk);
564 
565 	skb->destructor = sock_wfree;
566 	xsk_cq_cancel_locked(xs, xsk_get_num_desc(skb));
567 	/* Free skb without triggering the perf drop trace */
568 	consume_skb(skb);
569 	xs->skb = NULL;
570 }
571 
xsk_drop_skb(struct sk_buff * skb)572 static void xsk_drop_skb(struct sk_buff *skb)
573 {
574 	xdp_sk(skb->sk)->tx->invalid_descs += xsk_get_num_desc(skb);
575 	xsk_consume_skb(skb);
576 }
577 
xsk_build_skb_zerocopy(struct xdp_sock * xs,struct xdp_desc * desc)578 static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs,
579 					      struct xdp_desc *desc)
580 {
581 	struct xsk_buff_pool *pool = xs->pool;
582 	u32 hr, len, ts, offset, copy, copied;
583 	struct sk_buff *skb = xs->skb;
584 	struct page *page;
585 	void *buffer;
586 	int err, i;
587 	u64 addr;
588 
589 	if (!skb) {
590 		hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(xs->dev->needed_headroom));
591 
592 		skb = sock_alloc_send_skb(&xs->sk, hr, 1, &err);
593 		if (unlikely(!skb))
594 			return ERR_PTR(err);
595 
596 		skb_reserve(skb, hr);
597 	}
598 
599 	addr = desc->addr;
600 	len = desc->len;
601 	ts = pool->unaligned ? len : pool->chunk_size;
602 
603 	buffer = xsk_buff_raw_get_data(pool, addr);
604 	offset = offset_in_page(buffer);
605 	addr = buffer - pool->addrs;
606 
607 	for (copied = 0, i = skb_shinfo(skb)->nr_frags; copied < len; i++) {
608 		if (unlikely(i >= MAX_SKB_FRAGS))
609 			return ERR_PTR(-EOVERFLOW);
610 
611 		page = pool->umem->pgs[addr >> PAGE_SHIFT];
612 		get_page(page);
613 
614 		copy = min_t(u32, PAGE_SIZE - offset, len - copied);
615 		skb_fill_page_desc(skb, i, page, offset, copy);
616 
617 		copied += copy;
618 		addr += copy;
619 		offset = 0;
620 	}
621 
622 	skb->len += len;
623 	skb->data_len += len;
624 	skb->truesize += ts;
625 
626 	refcount_add(ts, &xs->sk.sk_wmem_alloc);
627 
628 	return skb;
629 }
630 
xsk_build_skb(struct xdp_sock * xs,struct xdp_desc * desc)631 static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
632 				     struct xdp_desc *desc)
633 {
634 	struct net_device *dev = xs->dev;
635 	struct sk_buff *skb = xs->skb;
636 	int err;
637 
638 	if (dev->priv_flags & IFF_TX_SKB_NO_LINEAR) {
639 		skb = xsk_build_skb_zerocopy(xs, desc);
640 		if (IS_ERR(skb)) {
641 			err = PTR_ERR(skb);
642 			goto free_err;
643 		}
644 	} else {
645 		u32 hr, tr, len;
646 		void *buffer;
647 
648 		buffer = xsk_buff_raw_get_data(xs->pool, desc->addr);
649 		len = desc->len;
650 
651 		if (!skb) {
652 			hr = max(NET_SKB_PAD, L1_CACHE_ALIGN(dev->needed_headroom));
653 			tr = dev->needed_tailroom;
654 			skb = sock_alloc_send_skb(&xs->sk, hr + len + tr, 1, &err);
655 			if (unlikely(!skb))
656 				goto free_err;
657 
658 			skb_reserve(skb, hr);
659 			skb_put(skb, len);
660 
661 			err = skb_store_bits(skb, 0, buffer, len);
662 			if (unlikely(err)) {
663 				kfree_skb(skb);
664 				goto free_err;
665 			}
666 		} else {
667 			int nr_frags = skb_shinfo(skb)->nr_frags;
668 			struct page *page;
669 			u8 *vaddr;
670 
671 			if (unlikely(nr_frags == (MAX_SKB_FRAGS - 1) && xp_mb_desc(desc))) {
672 				err = -EOVERFLOW;
673 				goto free_err;
674 			}
675 
676 			page = alloc_page(xs->sk.sk_allocation);
677 			if (unlikely(!page)) {
678 				err = -EAGAIN;
679 				goto free_err;
680 			}
681 
682 			vaddr = kmap_local_page(page);
683 			memcpy(vaddr, buffer, len);
684 			kunmap_local(vaddr);
685 
686 			skb_add_rx_frag(skb, nr_frags, page, 0, len, PAGE_SIZE);
687 			refcount_add(PAGE_SIZE, &xs->sk.sk_wmem_alloc);
688 		}
689 	}
690 
691 	skb->dev = dev;
692 	skb->priority = xs->sk.sk_priority;
693 	skb->mark = READ_ONCE(xs->sk.sk_mark);
694 	skb->destructor = xsk_destruct_skb;
695 	xsk_set_destructor_arg(skb);
696 
697 	return skb;
698 
699 free_err:
700 	if (err == -EOVERFLOW) {
701 		/* Drop the packet */
702 		xsk_set_destructor_arg(xs->skb);
703 		xsk_drop_skb(xs->skb);
704 		xskq_cons_release(xs->tx);
705 	} else {
706 		/* Let application retry */
707 		xsk_cq_cancel_locked(xs, 1);
708 	}
709 
710 	return ERR_PTR(err);
711 }
712 
__xsk_generic_xmit(struct sock * sk)713 static int __xsk_generic_xmit(struct sock *sk)
714 {
715 	struct xdp_sock *xs = xdp_sk(sk);
716 	u32 max_batch = TX_BATCH_SIZE;
717 	bool sent_frame = false;
718 	struct xdp_desc desc;
719 	struct sk_buff *skb;
720 	int err = 0;
721 
722 	mutex_lock(&xs->mutex);
723 
724 	/* Since we dropped the RCU read lock, the socket state might have changed. */
725 	if (unlikely(!xsk_is_bound(xs))) {
726 		err = -ENXIO;
727 		goto out;
728 	}
729 
730 	if (xs->queue_id >= xs->dev->real_num_tx_queues)
731 		goto out;
732 
733 	while (xskq_cons_peek_desc(xs->tx, &desc, xs->pool)) {
734 		if (max_batch-- == 0) {
735 			err = -EAGAIN;
736 			goto out;
737 		}
738 
739 		/* This is the backpressure mechanism for the Tx path.
740 		 * Reserve space in the completion queue and only proceed
741 		 * if there is space in it. This avoids having to implement
742 		 * any buffering in the Tx path.
743 		 */
744 		if (xsk_cq_reserve_addr_locked(xs, desc.addr))
745 			goto out;
746 
747 		skb = xsk_build_skb(xs, &desc);
748 		if (IS_ERR(skb)) {
749 			err = PTR_ERR(skb);
750 			if (err != -EOVERFLOW)
751 				goto out;
752 			err = 0;
753 			continue;
754 		}
755 
756 		xskq_cons_release(xs->tx);
757 
758 		if (xp_mb_desc(&desc)) {
759 			xs->skb = skb;
760 			continue;
761 		}
762 
763 		err = __dev_direct_xmit(skb, xs->queue_id);
764 		if  (err == NETDEV_TX_BUSY) {
765 			/* Tell user-space to retry the send */
766 			xskq_cons_cancel_n(xs->tx, xsk_get_num_desc(skb));
767 			xsk_consume_skb(skb);
768 			err = -EAGAIN;
769 			goto out;
770 		}
771 
772 		/* Ignore NET_XMIT_CN as packet might have been sent */
773 		if (err == NET_XMIT_DROP) {
774 			/* SKB completed but not sent */
775 			err = -EBUSY;
776 			xs->skb = NULL;
777 			goto out;
778 		}
779 
780 		sent_frame = true;
781 		xs->skb = NULL;
782 	}
783 
784 	if (xskq_has_descs(xs->tx)) {
785 		if (xs->skb)
786 			xsk_drop_skb(xs->skb);
787 		xskq_cons_release(xs->tx);
788 	}
789 
790 out:
791 	if (sent_frame)
792 		if (xsk_tx_writeable(xs))
793 			sk->sk_write_space(sk);
794 
795 	mutex_unlock(&xs->mutex);
796 	return err;
797 }
798 
xsk_generic_xmit(struct sock * sk)799 static int xsk_generic_xmit(struct sock *sk)
800 {
801 	int ret;
802 
803 	/* Drop the RCU lock since the SKB path might sleep. */
804 	rcu_read_unlock();
805 	ret = __xsk_generic_xmit(sk);
806 	/* Reaquire RCU lock before going into common code. */
807 	rcu_read_lock();
808 
809 	return ret;
810 }
811 
xsk_no_wakeup(struct sock * sk)812 static bool xsk_no_wakeup(struct sock *sk)
813 {
814 #ifdef CONFIG_NET_RX_BUSY_POLL
815 	/* Prefer busy-polling, skip the wakeup. */
816 	return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) &&
817 		READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID;
818 #else
819 	return false;
820 #endif
821 }
822 
xsk_check_common(struct xdp_sock * xs)823 static int xsk_check_common(struct xdp_sock *xs)
824 {
825 	if (unlikely(!xsk_is_bound(xs)))
826 		return -ENXIO;
827 	if (unlikely(!(xs->dev->flags & IFF_UP)))
828 		return -ENETDOWN;
829 
830 	return 0;
831 }
832 
__xsk_sendmsg(struct socket * sock,struct msghdr * m,size_t total_len)833 static int __xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
834 {
835 	bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
836 	struct sock *sk = sock->sk;
837 	struct xdp_sock *xs = xdp_sk(sk);
838 	struct xsk_buff_pool *pool;
839 	int err;
840 
841 	err = xsk_check_common(xs);
842 	if (err)
843 		return err;
844 	if (unlikely(need_wait))
845 		return -EOPNOTSUPP;
846 	if (unlikely(!xs->tx))
847 		return -ENOBUFS;
848 
849 	if (sk_can_busy_loop(sk)) {
850 		if (xs->zc)
851 			__sk_mark_napi_id_once(sk, xsk_pool_get_napi_id(xs->pool));
852 		sk_busy_loop(sk, 1); /* only support non-blocking sockets */
853 	}
854 
855 	if (xs->zc && xsk_no_wakeup(sk))
856 		return 0;
857 
858 	pool = xs->pool;
859 	if (pool->cached_need_wakeup & XDP_WAKEUP_TX) {
860 		if (xs->zc)
861 			return xsk_wakeup(xs, XDP_WAKEUP_TX);
862 		return xsk_generic_xmit(sk);
863 	}
864 	return 0;
865 }
866 
xsk_sendmsg(struct socket * sock,struct msghdr * m,size_t total_len)867 static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
868 {
869 	int ret;
870 
871 	rcu_read_lock();
872 	ret = __xsk_sendmsg(sock, m, total_len);
873 	rcu_read_unlock();
874 
875 	return ret;
876 }
877 
__xsk_recvmsg(struct socket * sock,struct msghdr * m,size_t len,int flags)878 static int __xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
879 {
880 	bool need_wait = !(flags & MSG_DONTWAIT);
881 	struct sock *sk = sock->sk;
882 	struct xdp_sock *xs = xdp_sk(sk);
883 	int err;
884 
885 	err = xsk_check_common(xs);
886 	if (err)
887 		return err;
888 	if (unlikely(!xs->rx))
889 		return -ENOBUFS;
890 	if (unlikely(need_wait))
891 		return -EOPNOTSUPP;
892 
893 	if (sk_can_busy_loop(sk))
894 		sk_busy_loop(sk, 1); /* only support non-blocking sockets */
895 
896 	if (xsk_no_wakeup(sk))
897 		return 0;
898 
899 	if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
900 		return xsk_wakeup(xs, XDP_WAKEUP_RX);
901 	return 0;
902 }
903 
xsk_recvmsg(struct socket * sock,struct msghdr * m,size_t len,int flags)904 static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
905 {
906 	int ret;
907 
908 	rcu_read_lock();
909 	ret = __xsk_recvmsg(sock, m, len, flags);
910 	rcu_read_unlock();
911 
912 	return ret;
913 }
914 
xsk_poll(struct file * file,struct socket * sock,struct poll_table_struct * wait)915 static __poll_t xsk_poll(struct file *file, struct socket *sock,
916 			     struct poll_table_struct *wait)
917 {
918 	__poll_t mask = 0;
919 	struct sock *sk = sock->sk;
920 	struct xdp_sock *xs = xdp_sk(sk);
921 	struct xsk_buff_pool *pool;
922 
923 	sock_poll_wait(file, sock, wait);
924 
925 	rcu_read_lock();
926 	if (xsk_check_common(xs))
927 		goto out;
928 
929 	pool = xs->pool;
930 
931 	if (pool->cached_need_wakeup) {
932 		if (xs->zc)
933 			xsk_wakeup(xs, pool->cached_need_wakeup);
934 		else if (xs->tx)
935 			/* Poll needs to drive Tx also in copy mode */
936 			xsk_generic_xmit(sk);
937 	}
938 
939 	if (xs->rx && !xskq_prod_is_empty(xs->rx))
940 		mask |= EPOLLIN | EPOLLRDNORM;
941 	if (xs->tx && xsk_tx_writeable(xs))
942 		mask |= EPOLLOUT | EPOLLWRNORM;
943 out:
944 	rcu_read_unlock();
945 	return mask;
946 }
947 
xsk_init_queue(u32 entries,struct xsk_queue ** queue,bool umem_queue)948 static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
949 			  bool umem_queue)
950 {
951 	struct xsk_queue *q;
952 
953 	if (entries == 0 || *queue || !is_power_of_2(entries))
954 		return -EINVAL;
955 
956 	q = xskq_create(entries, umem_queue);
957 	if (!q)
958 		return -ENOMEM;
959 
960 	/* Make sure queue is ready before it can be seen by others */
961 	smp_wmb();
962 	WRITE_ONCE(*queue, q);
963 	return 0;
964 }
965 
xsk_unbind_dev(struct xdp_sock * xs)966 static void xsk_unbind_dev(struct xdp_sock *xs)
967 {
968 	struct net_device *dev = xs->dev;
969 
970 	if (xs->state != XSK_BOUND)
971 		return;
972 	WRITE_ONCE(xs->state, XSK_UNBOUND);
973 
974 	/* Wait for driver to stop using the xdp socket. */
975 	xp_del_xsk(xs->pool, xs);
976 	synchronize_net();
977 	dev_put(dev);
978 }
979 
xsk_get_map_list_entry(struct xdp_sock * xs,struct xdp_sock __rcu *** map_entry)980 static struct xsk_map *xsk_get_map_list_entry(struct xdp_sock *xs,
981 					      struct xdp_sock __rcu ***map_entry)
982 {
983 	struct xsk_map *map = NULL;
984 	struct xsk_map_node *node;
985 
986 	*map_entry = NULL;
987 
988 	spin_lock_bh(&xs->map_list_lock);
989 	node = list_first_entry_or_null(&xs->map_list, struct xsk_map_node,
990 					node);
991 	if (node) {
992 		bpf_map_inc(&node->map->map);
993 		map = node->map;
994 		*map_entry = node->map_entry;
995 	}
996 	spin_unlock_bh(&xs->map_list_lock);
997 	return map;
998 }
999 
xsk_delete_from_maps(struct xdp_sock * xs)1000 static void xsk_delete_from_maps(struct xdp_sock *xs)
1001 {
1002 	/* This function removes the current XDP socket from all the
1003 	 * maps it resides in. We need to take extra care here, due to
1004 	 * the two locks involved. Each map has a lock synchronizing
1005 	 * updates to the entries, and each socket has a lock that
1006 	 * synchronizes access to the list of maps (map_list). For
1007 	 * deadlock avoidance the locks need to be taken in the order
1008 	 * "map lock"->"socket map list lock". We start off by
1009 	 * accessing the socket map list, and take a reference to the
1010 	 * map to guarantee existence between the
1011 	 * xsk_get_map_list_entry() and xsk_map_try_sock_delete()
1012 	 * calls. Then we ask the map to remove the socket, which
1013 	 * tries to remove the socket from the map. Note that there
1014 	 * might be updates to the map between
1015 	 * xsk_get_map_list_entry() and xsk_map_try_sock_delete().
1016 	 */
1017 	struct xdp_sock __rcu **map_entry = NULL;
1018 	struct xsk_map *map;
1019 
1020 	while ((map = xsk_get_map_list_entry(xs, &map_entry))) {
1021 		xsk_map_try_sock_delete(map, xs, map_entry);
1022 		bpf_map_put(&map->map);
1023 	}
1024 }
1025 
xsk_release(struct socket * sock)1026 static int xsk_release(struct socket *sock)
1027 {
1028 	struct sock *sk = sock->sk;
1029 	struct xdp_sock *xs = xdp_sk(sk);
1030 	struct net *net;
1031 
1032 	if (!sk)
1033 		return 0;
1034 
1035 	net = sock_net(sk);
1036 
1037 	if (xs->skb)
1038 		xsk_drop_skb(xs->skb);
1039 
1040 	mutex_lock(&net->xdp.lock);
1041 	sk_del_node_init_rcu(sk);
1042 	mutex_unlock(&net->xdp.lock);
1043 
1044 	sock_prot_inuse_add(net, sk->sk_prot, -1);
1045 
1046 	xsk_delete_from_maps(xs);
1047 	mutex_lock(&xs->mutex);
1048 	xsk_unbind_dev(xs);
1049 	mutex_unlock(&xs->mutex);
1050 
1051 	xskq_destroy(xs->rx);
1052 	xskq_destroy(xs->tx);
1053 	xskq_destroy(xs->fq_tmp);
1054 	xskq_destroy(xs->cq_tmp);
1055 
1056 	sock_orphan(sk);
1057 	sock->sk = NULL;
1058 
1059 	sock_put(sk);
1060 
1061 	return 0;
1062 }
1063 
xsk_lookup_xsk_from_fd(int fd)1064 static struct socket *xsk_lookup_xsk_from_fd(int fd)
1065 {
1066 	struct socket *sock;
1067 	int err;
1068 
1069 	sock = sockfd_lookup(fd, &err);
1070 	if (!sock)
1071 		return ERR_PTR(-ENOTSOCK);
1072 
1073 	if (sock->sk->sk_family != PF_XDP) {
1074 		sockfd_put(sock);
1075 		return ERR_PTR(-ENOPROTOOPT);
1076 	}
1077 
1078 	return sock;
1079 }
1080 
xsk_validate_queues(struct xdp_sock * xs)1081 static bool xsk_validate_queues(struct xdp_sock *xs)
1082 {
1083 	return xs->fq_tmp && xs->cq_tmp;
1084 }
1085 
xsk_bind(struct socket * sock,struct sockaddr * addr,int addr_len)1086 static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
1087 {
1088 	struct sockaddr_xdp *sxdp = (struct sockaddr_xdp *)addr;
1089 	struct sock *sk = sock->sk;
1090 	struct xdp_sock *xs = xdp_sk(sk);
1091 	struct net_device *dev;
1092 	int bound_dev_if;
1093 	u32 flags, qid;
1094 	int err = 0;
1095 
1096 	if (addr_len < sizeof(struct sockaddr_xdp))
1097 		return -EINVAL;
1098 	if (sxdp->sxdp_family != AF_XDP)
1099 		return -EINVAL;
1100 
1101 	flags = sxdp->sxdp_flags;
1102 	if (flags & ~(XDP_SHARED_UMEM | XDP_COPY | XDP_ZEROCOPY |
1103 		      XDP_USE_NEED_WAKEUP | XDP_USE_SG))
1104 		return -EINVAL;
1105 
1106 	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
1107 	if (bound_dev_if && bound_dev_if != sxdp->sxdp_ifindex)
1108 		return -EINVAL;
1109 
1110 	rtnl_lock();
1111 	mutex_lock(&xs->mutex);
1112 	if (xs->state != XSK_READY) {
1113 		err = -EBUSY;
1114 		goto out_release;
1115 	}
1116 
1117 	dev = dev_get_by_index(sock_net(sk), sxdp->sxdp_ifindex);
1118 	if (!dev) {
1119 		err = -ENODEV;
1120 		goto out_release;
1121 	}
1122 
1123 	if (!xs->rx && !xs->tx) {
1124 		err = -EINVAL;
1125 		goto out_unlock;
1126 	}
1127 
1128 	qid = sxdp->sxdp_queue_id;
1129 
1130 	if (flags & XDP_SHARED_UMEM) {
1131 		struct xdp_sock *umem_xs;
1132 		struct socket *sock;
1133 
1134 		if ((flags & XDP_COPY) || (flags & XDP_ZEROCOPY) ||
1135 		    (flags & XDP_USE_NEED_WAKEUP) || (flags & XDP_USE_SG)) {
1136 			/* Cannot specify flags for shared sockets. */
1137 			err = -EINVAL;
1138 			goto out_unlock;
1139 		}
1140 
1141 		if (xs->umem) {
1142 			/* We have already our own. */
1143 			err = -EINVAL;
1144 			goto out_unlock;
1145 		}
1146 
1147 		sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd);
1148 		if (IS_ERR(sock)) {
1149 			err = PTR_ERR(sock);
1150 			goto out_unlock;
1151 		}
1152 
1153 		umem_xs = xdp_sk(sock->sk);
1154 		if (!xsk_is_bound(umem_xs)) {
1155 			err = -EBADF;
1156 			sockfd_put(sock);
1157 			goto out_unlock;
1158 		}
1159 
1160 		if (umem_xs->queue_id != qid || umem_xs->dev != dev) {
1161 			/* Share the umem with another socket on another qid
1162 			 * and/or device.
1163 			 */
1164 			xs->pool = xp_create_and_assign_umem(xs,
1165 							     umem_xs->umem);
1166 			if (!xs->pool) {
1167 				err = -ENOMEM;
1168 				sockfd_put(sock);
1169 				goto out_unlock;
1170 			}
1171 
1172 			err = xp_assign_dev_shared(xs->pool, umem_xs, dev,
1173 						   qid);
1174 			if (err) {
1175 				xp_destroy(xs->pool);
1176 				xs->pool = NULL;
1177 				sockfd_put(sock);
1178 				goto out_unlock;
1179 			}
1180 		} else {
1181 			/* Share the buffer pool with the other socket. */
1182 			if (xs->fq_tmp || xs->cq_tmp) {
1183 				/* Do not allow setting your own fq or cq. */
1184 				err = -EINVAL;
1185 				sockfd_put(sock);
1186 				goto out_unlock;
1187 			}
1188 
1189 			xp_get_pool(umem_xs->pool);
1190 			xs->pool = umem_xs->pool;
1191 
1192 			/* If underlying shared umem was created without Tx
1193 			 * ring, allocate Tx descs array that Tx batching API
1194 			 * utilizes
1195 			 */
1196 			if (xs->tx && !xs->pool->tx_descs) {
1197 				err = xp_alloc_tx_descs(xs->pool, xs);
1198 				if (err) {
1199 					xp_put_pool(xs->pool);
1200 					xs->pool = NULL;
1201 					sockfd_put(sock);
1202 					goto out_unlock;
1203 				}
1204 			}
1205 		}
1206 
1207 		xdp_get_umem(umem_xs->umem);
1208 		WRITE_ONCE(xs->umem, umem_xs->umem);
1209 		sockfd_put(sock);
1210 	} else if (!xs->umem || !xsk_validate_queues(xs)) {
1211 		err = -EINVAL;
1212 		goto out_unlock;
1213 	} else {
1214 		/* This xsk has its own umem. */
1215 		xs->pool = xp_create_and_assign_umem(xs, xs->umem);
1216 		if (!xs->pool) {
1217 			err = -ENOMEM;
1218 			goto out_unlock;
1219 		}
1220 
1221 		err = xp_assign_dev(xs->pool, dev, qid, flags);
1222 		if (err) {
1223 			xp_destroy(xs->pool);
1224 			xs->pool = NULL;
1225 			goto out_unlock;
1226 		}
1227 	}
1228 
1229 	/* FQ and CQ are now owned by the buffer pool and cleaned up with it. */
1230 	xs->fq_tmp = NULL;
1231 	xs->cq_tmp = NULL;
1232 
1233 	xs->dev = dev;
1234 	xs->zc = xs->umem->zc;
1235 	xs->sg = !!(xs->umem->flags & XDP_UMEM_SG_FLAG);
1236 	xs->queue_id = qid;
1237 	xp_add_xsk(xs->pool, xs);
1238 
1239 out_unlock:
1240 	if (err) {
1241 		dev_put(dev);
1242 	} else {
1243 		/* Matches smp_rmb() in bind() for shared umem
1244 		 * sockets, and xsk_is_bound().
1245 		 */
1246 		smp_wmb();
1247 		WRITE_ONCE(xs->state, XSK_BOUND);
1248 	}
1249 out_release:
1250 	mutex_unlock(&xs->mutex);
1251 	rtnl_unlock();
1252 	return err;
1253 }
1254 
1255 struct xdp_umem_reg_v1 {
1256 	__u64 addr; /* Start of packet data area */
1257 	__u64 len; /* Length of packet data area */
1258 	__u32 chunk_size;
1259 	__u32 headroom;
1260 };
1261 
xsk_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1262 static int xsk_setsockopt(struct socket *sock, int level, int optname,
1263 			  sockptr_t optval, unsigned int optlen)
1264 {
1265 	struct sock *sk = sock->sk;
1266 	struct xdp_sock *xs = xdp_sk(sk);
1267 	int err;
1268 
1269 	if (level != SOL_XDP)
1270 		return -ENOPROTOOPT;
1271 
1272 	switch (optname) {
1273 	case XDP_RX_RING:
1274 	case XDP_TX_RING:
1275 	{
1276 		struct xsk_queue **q;
1277 		int entries;
1278 
1279 		if (optlen < sizeof(entries))
1280 			return -EINVAL;
1281 		if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1282 			return -EFAULT;
1283 
1284 		mutex_lock(&xs->mutex);
1285 		if (xs->state != XSK_READY) {
1286 			mutex_unlock(&xs->mutex);
1287 			return -EBUSY;
1288 		}
1289 		q = (optname == XDP_TX_RING) ? &xs->tx : &xs->rx;
1290 		err = xsk_init_queue(entries, q, false);
1291 		if (!err && optname == XDP_TX_RING)
1292 			/* Tx needs to be explicitly woken up the first time */
1293 			xs->tx->ring->flags |= XDP_RING_NEED_WAKEUP;
1294 		mutex_unlock(&xs->mutex);
1295 		return err;
1296 	}
1297 	case XDP_UMEM_REG:
1298 	{
1299 		size_t mr_size = sizeof(struct xdp_umem_reg);
1300 		struct xdp_umem_reg mr = {};
1301 		struct xdp_umem *umem;
1302 
1303 		if (optlen < sizeof(struct xdp_umem_reg_v1))
1304 			return -EINVAL;
1305 		else if (optlen < sizeof(mr))
1306 			mr_size = sizeof(struct xdp_umem_reg_v1);
1307 
1308 		if (copy_from_sockptr(&mr, optval, mr_size))
1309 			return -EFAULT;
1310 
1311 		mutex_lock(&xs->mutex);
1312 		if (xs->state != XSK_READY || xs->umem) {
1313 			mutex_unlock(&xs->mutex);
1314 			return -EBUSY;
1315 		}
1316 
1317 		umem = xdp_umem_create(&mr);
1318 		if (IS_ERR(umem)) {
1319 			mutex_unlock(&xs->mutex);
1320 			return PTR_ERR(umem);
1321 		}
1322 
1323 		/* Make sure umem is ready before it can be seen by others */
1324 		smp_wmb();
1325 		WRITE_ONCE(xs->umem, umem);
1326 		mutex_unlock(&xs->mutex);
1327 		return 0;
1328 	}
1329 	case XDP_UMEM_FILL_RING:
1330 	case XDP_UMEM_COMPLETION_RING:
1331 	{
1332 		struct xsk_queue **q;
1333 		int entries;
1334 
1335 		if (optlen < sizeof(entries))
1336 			return -EINVAL;
1337 		if (copy_from_sockptr(&entries, optval, sizeof(entries)))
1338 			return -EFAULT;
1339 
1340 		mutex_lock(&xs->mutex);
1341 		if (xs->state != XSK_READY) {
1342 			mutex_unlock(&xs->mutex);
1343 			return -EBUSY;
1344 		}
1345 
1346 		q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp :
1347 			&xs->cq_tmp;
1348 		err = xsk_init_queue(entries, q, true);
1349 		mutex_unlock(&xs->mutex);
1350 		return err;
1351 	}
1352 	default:
1353 		break;
1354 	}
1355 
1356 	return -ENOPROTOOPT;
1357 }
1358 
xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 * ring)1359 static void xsk_enter_rxtx_offsets(struct xdp_ring_offset_v1 *ring)
1360 {
1361 	ring->producer = offsetof(struct xdp_rxtx_ring, ptrs.producer);
1362 	ring->consumer = offsetof(struct xdp_rxtx_ring, ptrs.consumer);
1363 	ring->desc = offsetof(struct xdp_rxtx_ring, desc);
1364 }
1365 
xsk_enter_umem_offsets(struct xdp_ring_offset_v1 * ring)1366 static void xsk_enter_umem_offsets(struct xdp_ring_offset_v1 *ring)
1367 {
1368 	ring->producer = offsetof(struct xdp_umem_ring, ptrs.producer);
1369 	ring->consumer = offsetof(struct xdp_umem_ring, ptrs.consumer);
1370 	ring->desc = offsetof(struct xdp_umem_ring, desc);
1371 }
1372 
1373 struct xdp_statistics_v1 {
1374 	__u64 rx_dropped;
1375 	__u64 rx_invalid_descs;
1376 	__u64 tx_invalid_descs;
1377 };
1378 
xsk_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1379 static int xsk_getsockopt(struct socket *sock, int level, int optname,
1380 			  char __user *optval, int __user *optlen)
1381 {
1382 	struct sock *sk = sock->sk;
1383 	struct xdp_sock *xs = xdp_sk(sk);
1384 	int len;
1385 
1386 	if (level != SOL_XDP)
1387 		return -ENOPROTOOPT;
1388 
1389 	if (get_user(len, optlen))
1390 		return -EFAULT;
1391 	if (len < 0)
1392 		return -EINVAL;
1393 
1394 	switch (optname) {
1395 	case XDP_STATISTICS:
1396 	{
1397 		struct xdp_statistics stats = {};
1398 		bool extra_stats = true;
1399 		size_t stats_size;
1400 
1401 		if (len < sizeof(struct xdp_statistics_v1)) {
1402 			return -EINVAL;
1403 		} else if (len < sizeof(stats)) {
1404 			extra_stats = false;
1405 			stats_size = sizeof(struct xdp_statistics_v1);
1406 		} else {
1407 			stats_size = sizeof(stats);
1408 		}
1409 
1410 		mutex_lock(&xs->mutex);
1411 		stats.rx_dropped = xs->rx_dropped;
1412 		if (extra_stats) {
1413 			stats.rx_ring_full = xs->rx_queue_full;
1414 			stats.rx_fill_ring_empty_descs =
1415 				xs->pool ? xskq_nb_queue_empty_descs(xs->pool->fq) : 0;
1416 			stats.tx_ring_empty_descs = xskq_nb_queue_empty_descs(xs->tx);
1417 		} else {
1418 			stats.rx_dropped += xs->rx_queue_full;
1419 		}
1420 		stats.rx_invalid_descs = xskq_nb_invalid_descs(xs->rx);
1421 		stats.tx_invalid_descs = xskq_nb_invalid_descs(xs->tx);
1422 		mutex_unlock(&xs->mutex);
1423 
1424 		if (copy_to_user(optval, &stats, stats_size))
1425 			return -EFAULT;
1426 		if (put_user(stats_size, optlen))
1427 			return -EFAULT;
1428 
1429 		return 0;
1430 	}
1431 	case XDP_MMAP_OFFSETS:
1432 	{
1433 		struct xdp_mmap_offsets off;
1434 		struct xdp_mmap_offsets_v1 off_v1;
1435 		bool flags_supported = true;
1436 		void *to_copy;
1437 
1438 		if (len < sizeof(off_v1))
1439 			return -EINVAL;
1440 		else if (len < sizeof(off))
1441 			flags_supported = false;
1442 
1443 		if (flags_supported) {
1444 			/* xdp_ring_offset is identical to xdp_ring_offset_v1
1445 			 * except for the flags field added to the end.
1446 			 */
1447 			xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1448 					       &off.rx);
1449 			xsk_enter_rxtx_offsets((struct xdp_ring_offset_v1 *)
1450 					       &off.tx);
1451 			xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1452 					       &off.fr);
1453 			xsk_enter_umem_offsets((struct xdp_ring_offset_v1 *)
1454 					       &off.cr);
1455 			off.rx.flags = offsetof(struct xdp_rxtx_ring,
1456 						ptrs.flags);
1457 			off.tx.flags = offsetof(struct xdp_rxtx_ring,
1458 						ptrs.flags);
1459 			off.fr.flags = offsetof(struct xdp_umem_ring,
1460 						ptrs.flags);
1461 			off.cr.flags = offsetof(struct xdp_umem_ring,
1462 						ptrs.flags);
1463 
1464 			len = sizeof(off);
1465 			to_copy = &off;
1466 		} else {
1467 			xsk_enter_rxtx_offsets(&off_v1.rx);
1468 			xsk_enter_rxtx_offsets(&off_v1.tx);
1469 			xsk_enter_umem_offsets(&off_v1.fr);
1470 			xsk_enter_umem_offsets(&off_v1.cr);
1471 
1472 			len = sizeof(off_v1);
1473 			to_copy = &off_v1;
1474 		}
1475 
1476 		if (copy_to_user(optval, to_copy, len))
1477 			return -EFAULT;
1478 		if (put_user(len, optlen))
1479 			return -EFAULT;
1480 
1481 		return 0;
1482 	}
1483 	case XDP_OPTIONS:
1484 	{
1485 		struct xdp_options opts = {};
1486 
1487 		if (len < sizeof(opts))
1488 			return -EINVAL;
1489 
1490 		mutex_lock(&xs->mutex);
1491 		if (xs->zc)
1492 			opts.flags |= XDP_OPTIONS_ZEROCOPY;
1493 		mutex_unlock(&xs->mutex);
1494 
1495 		len = sizeof(opts);
1496 		if (copy_to_user(optval, &opts, len))
1497 			return -EFAULT;
1498 		if (put_user(len, optlen))
1499 			return -EFAULT;
1500 
1501 		return 0;
1502 	}
1503 	default:
1504 		break;
1505 	}
1506 
1507 	return -EOPNOTSUPP;
1508 }
1509 
xsk_mmap(struct file * file,struct socket * sock,struct vm_area_struct * vma)1510 static int xsk_mmap(struct file *file, struct socket *sock,
1511 		    struct vm_area_struct *vma)
1512 {
1513 	loff_t offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
1514 	unsigned long size = vma->vm_end - vma->vm_start;
1515 	struct xdp_sock *xs = xdp_sk(sock->sk);
1516 	int state = READ_ONCE(xs->state);
1517 	struct xsk_queue *q = NULL;
1518 
1519 	if (state != XSK_READY && state != XSK_BOUND)
1520 		return -EBUSY;
1521 
1522 	if (offset == XDP_PGOFF_RX_RING) {
1523 		q = READ_ONCE(xs->rx);
1524 	} else if (offset == XDP_PGOFF_TX_RING) {
1525 		q = READ_ONCE(xs->tx);
1526 	} else {
1527 		/* Matches the smp_wmb() in XDP_UMEM_REG */
1528 		smp_rmb();
1529 		if (offset == XDP_UMEM_PGOFF_FILL_RING)
1530 			q = state == XSK_READY ? READ_ONCE(xs->fq_tmp) :
1531 						 READ_ONCE(xs->pool->fq);
1532 		else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
1533 			q = state == XSK_READY ? READ_ONCE(xs->cq_tmp) :
1534 						 READ_ONCE(xs->pool->cq);
1535 	}
1536 
1537 	if (!q)
1538 		return -EINVAL;
1539 
1540 	/* Matches the smp_wmb() in xsk_init_queue */
1541 	smp_rmb();
1542 	if (size > q->ring_vmalloc_size)
1543 		return -EINVAL;
1544 
1545 	return remap_vmalloc_range(vma, q->ring, 0);
1546 }
1547 
xsk_notifier(struct notifier_block * this,unsigned long msg,void * ptr)1548 static int xsk_notifier(struct notifier_block *this,
1549 			unsigned long msg, void *ptr)
1550 {
1551 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1552 	struct net *net = dev_net(dev);
1553 	struct sock *sk;
1554 
1555 	switch (msg) {
1556 	case NETDEV_UNREGISTER:
1557 		mutex_lock(&net->xdp.lock);
1558 		sk_for_each(sk, &net->xdp.list) {
1559 			struct xdp_sock *xs = xdp_sk(sk);
1560 
1561 			mutex_lock(&xs->mutex);
1562 			if (xs->dev == dev) {
1563 				sk->sk_err = ENETDOWN;
1564 				if (!sock_flag(sk, SOCK_DEAD))
1565 					sk_error_report(sk);
1566 
1567 				xsk_unbind_dev(xs);
1568 
1569 				/* Clear device references. */
1570 				xp_clear_dev(xs->pool);
1571 			}
1572 			mutex_unlock(&xs->mutex);
1573 		}
1574 		mutex_unlock(&net->xdp.lock);
1575 		break;
1576 	}
1577 	return NOTIFY_DONE;
1578 }
1579 
1580 static struct proto xsk_proto = {
1581 	.name =		"XDP",
1582 	.owner =	THIS_MODULE,
1583 	.obj_size =	sizeof(struct xdp_sock),
1584 };
1585 
1586 static const struct proto_ops xsk_proto_ops = {
1587 	.family		= PF_XDP,
1588 	.owner		= THIS_MODULE,
1589 	.release	= xsk_release,
1590 	.bind		= xsk_bind,
1591 	.connect	= sock_no_connect,
1592 	.socketpair	= sock_no_socketpair,
1593 	.accept		= sock_no_accept,
1594 	.getname	= sock_no_getname,
1595 	.poll		= xsk_poll,
1596 	.ioctl		= sock_no_ioctl,
1597 	.listen		= sock_no_listen,
1598 	.shutdown	= sock_no_shutdown,
1599 	.setsockopt	= xsk_setsockopt,
1600 	.getsockopt	= xsk_getsockopt,
1601 	.sendmsg	= xsk_sendmsg,
1602 	.recvmsg	= xsk_recvmsg,
1603 	.mmap		= xsk_mmap,
1604 };
1605 
xsk_destruct(struct sock * sk)1606 static void xsk_destruct(struct sock *sk)
1607 {
1608 	struct xdp_sock *xs = xdp_sk(sk);
1609 
1610 	if (!sock_flag(sk, SOCK_DEAD))
1611 		return;
1612 
1613 	if (!xp_put_pool(xs->pool))
1614 		xdp_put_umem(xs->umem, !xs->pool);
1615 }
1616 
xsk_create(struct net * net,struct socket * sock,int protocol,int kern)1617 static int xsk_create(struct net *net, struct socket *sock, int protocol,
1618 		      int kern)
1619 {
1620 	struct xdp_sock *xs;
1621 	struct sock *sk;
1622 
1623 	if (!ns_capable(net->user_ns, CAP_NET_RAW))
1624 		return -EPERM;
1625 	if (sock->type != SOCK_RAW)
1626 		return -ESOCKTNOSUPPORT;
1627 
1628 	if (protocol)
1629 		return -EPROTONOSUPPORT;
1630 
1631 	sock->state = SS_UNCONNECTED;
1632 
1633 	sk = sk_alloc(net, PF_XDP, GFP_KERNEL, &xsk_proto, kern);
1634 	if (!sk)
1635 		return -ENOBUFS;
1636 
1637 	sock->ops = &xsk_proto_ops;
1638 
1639 	sock_init_data(sock, sk);
1640 
1641 	sk->sk_family = PF_XDP;
1642 
1643 	sk->sk_destruct = xsk_destruct;
1644 
1645 	sock_set_flag(sk, SOCK_RCU_FREE);
1646 
1647 	xs = xdp_sk(sk);
1648 	xs->state = XSK_READY;
1649 	mutex_init(&xs->mutex);
1650 	spin_lock_init(&xs->rx_lock);
1651 
1652 	INIT_LIST_HEAD(&xs->map_list);
1653 	spin_lock_init(&xs->map_list_lock);
1654 
1655 	mutex_lock(&net->xdp.lock);
1656 	sk_add_node_rcu(sk, &net->xdp.list);
1657 	mutex_unlock(&net->xdp.lock);
1658 
1659 	sock_prot_inuse_add(net, &xsk_proto, 1);
1660 
1661 	return 0;
1662 }
1663 
1664 static const struct net_proto_family xsk_family_ops = {
1665 	.family = PF_XDP,
1666 	.create = xsk_create,
1667 	.owner	= THIS_MODULE,
1668 };
1669 
1670 static struct notifier_block xsk_netdev_notifier = {
1671 	.notifier_call	= xsk_notifier,
1672 };
1673 
xsk_net_init(struct net * net)1674 static int __net_init xsk_net_init(struct net *net)
1675 {
1676 	mutex_init(&net->xdp.lock);
1677 	INIT_HLIST_HEAD(&net->xdp.list);
1678 	return 0;
1679 }
1680 
xsk_net_exit(struct net * net)1681 static void __net_exit xsk_net_exit(struct net *net)
1682 {
1683 	WARN_ON_ONCE(!hlist_empty(&net->xdp.list));
1684 }
1685 
1686 static struct pernet_operations xsk_net_ops = {
1687 	.init = xsk_net_init,
1688 	.exit = xsk_net_exit,
1689 };
1690 
xsk_init(void)1691 static int __init xsk_init(void)
1692 {
1693 	int err, cpu;
1694 
1695 	err = proto_register(&xsk_proto, 0 /* no slab */);
1696 	if (err)
1697 		goto out;
1698 
1699 	err = sock_register(&xsk_family_ops);
1700 	if (err)
1701 		goto out_proto;
1702 
1703 	err = register_pernet_subsys(&xsk_net_ops);
1704 	if (err)
1705 		goto out_sk;
1706 
1707 	err = register_netdevice_notifier(&xsk_netdev_notifier);
1708 	if (err)
1709 		goto out_pernet;
1710 
1711 	for_each_possible_cpu(cpu)
1712 		INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
1713 	return 0;
1714 
1715 out_pernet:
1716 	unregister_pernet_subsys(&xsk_net_ops);
1717 out_sk:
1718 	sock_unregister(PF_XDP);
1719 out_proto:
1720 	proto_unregister(&xsk_proto);
1721 out:
1722 	return err;
1723 }
1724 
1725 fs_initcall(xsk_init);
1726