xref: /openbmc/linux/drivers/net/veth.c (revision 7288dd2f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  drivers/net/veth.c
4  *
5  *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
6  *
7  * Author: Pavel Emelianov <xemul@openvz.org>
8  * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
9  *
10  */
11 
12 #include <linux/netdevice.h>
13 #include <linux/slab.h>
14 #include <linux/ethtool.h>
15 #include <linux/etherdevice.h>
16 #include <linux/u64_stats_sync.h>
17 
18 #include <net/rtnetlink.h>
19 #include <net/dst.h>
20 #include <net/xfrm.h>
21 #include <net/xdp.h>
22 #include <linux/veth.h>
23 #include <linux/module.h>
24 #include <linux/bpf.h>
25 #include <linux/filter.h>
26 #include <linux/ptr_ring.h>
27 #include <linux/bpf_trace.h>
28 #include <linux/net_tstamp.h>
29 #include <net/page_pool/helpers.h>
30 
31 #define DRV_NAME	"veth"
32 #define DRV_VERSION	"1.0"
33 
34 #define VETH_XDP_FLAG		BIT(0)
35 #define VETH_RING_SIZE		256
36 #define VETH_XDP_HEADROOM	(XDP_PACKET_HEADROOM + NET_IP_ALIGN)
37 
38 #define VETH_XDP_TX_BULK_SIZE	16
39 #define VETH_XDP_BATCH		16
40 
41 struct veth_stats {
42 	u64	rx_drops;
43 	/* xdp */
44 	u64	xdp_packets;
45 	u64	xdp_bytes;
46 	u64	xdp_redirect;
47 	u64	xdp_drops;
48 	u64	xdp_tx;
49 	u64	xdp_tx_err;
50 	u64	peer_tq_xdp_xmit;
51 	u64	peer_tq_xdp_xmit_err;
52 };
53 
54 struct veth_rq_stats {
55 	struct veth_stats	vs;
56 	struct u64_stats_sync	syncp;
57 };
58 
59 struct veth_rq {
60 	struct napi_struct	xdp_napi;
61 	struct napi_struct __rcu *napi; /* points to xdp_napi when the latter is initialized */
62 	struct net_device	*dev;
63 	struct bpf_prog __rcu	*xdp_prog;
64 	struct xdp_mem_info	xdp_mem;
65 	struct veth_rq_stats	stats;
66 	bool			rx_notify_masked;
67 	struct ptr_ring		xdp_ring;
68 	struct xdp_rxq_info	xdp_rxq;
69 	struct page_pool	*page_pool;
70 };
71 
72 struct veth_priv {
73 	struct net_device __rcu	*peer;
74 	atomic64_t		dropped;
75 	struct bpf_prog		*_xdp_prog;
76 	struct veth_rq		*rq;
77 	unsigned int		requested_headroom;
78 };
79 
80 struct veth_xdp_tx_bq {
81 	struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
82 	unsigned int count;
83 };
84 
85 /*
86  * ethtool interface
87  */
88 
89 struct veth_q_stat_desc {
90 	char	desc[ETH_GSTRING_LEN];
91 	size_t	offset;
92 };
93 
94 #define VETH_RQ_STAT(m)	offsetof(struct veth_stats, m)
95 
96 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
97 	{ "xdp_packets",	VETH_RQ_STAT(xdp_packets) },
98 	{ "xdp_bytes",		VETH_RQ_STAT(xdp_bytes) },
99 	{ "drops",		VETH_RQ_STAT(rx_drops) },
100 	{ "xdp_redirect",	VETH_RQ_STAT(xdp_redirect) },
101 	{ "xdp_drops",		VETH_RQ_STAT(xdp_drops) },
102 	{ "xdp_tx",		VETH_RQ_STAT(xdp_tx) },
103 	{ "xdp_tx_errors",	VETH_RQ_STAT(xdp_tx_err) },
104 };
105 
106 #define VETH_RQ_STATS_LEN	ARRAY_SIZE(veth_rq_stats_desc)
107 
108 static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
109 	{ "xdp_xmit",		VETH_RQ_STAT(peer_tq_xdp_xmit) },
110 	{ "xdp_xmit_errors",	VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
111 };
112 
113 #define VETH_TQ_STATS_LEN	ARRAY_SIZE(veth_tq_stats_desc)
114 
115 static struct {
116 	const char string[ETH_GSTRING_LEN];
117 } ethtool_stats_keys[] = {
118 	{ "peer_ifindex" },
119 };
120 
121 struct veth_xdp_buff {
122 	struct xdp_buff xdp;
123 	struct sk_buff *skb;
124 };
125 
126 static int veth_get_link_ksettings(struct net_device *dev,
127 				   struct ethtool_link_ksettings *cmd)
128 {
129 	cmd->base.speed		= SPEED_10000;
130 	cmd->base.duplex	= DUPLEX_FULL;
131 	cmd->base.port		= PORT_TP;
132 	cmd->base.autoneg	= AUTONEG_DISABLE;
133 	return 0;
134 }
135 
136 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
137 {
138 	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
139 	strscpy(info->version, DRV_VERSION, sizeof(info->version));
140 }
141 
142 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
143 {
144 	u8 *p = buf;
145 	int i, j;
146 
147 	switch(stringset) {
148 	case ETH_SS_STATS:
149 		memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
150 		p += sizeof(ethtool_stats_keys);
151 		for (i = 0; i < dev->real_num_rx_queues; i++)
152 			for (j = 0; j < VETH_RQ_STATS_LEN; j++)
153 				ethtool_sprintf(&p, "rx_queue_%u_%.18s",
154 						i, veth_rq_stats_desc[j].desc);
155 
156 		for (i = 0; i < dev->real_num_tx_queues; i++)
157 			for (j = 0; j < VETH_TQ_STATS_LEN; j++)
158 				ethtool_sprintf(&p, "tx_queue_%u_%.18s",
159 						i, veth_tq_stats_desc[j].desc);
160 
161 		page_pool_ethtool_stats_get_strings(p);
162 		break;
163 	}
164 }
165 
166 static int veth_get_sset_count(struct net_device *dev, int sset)
167 {
168 	switch (sset) {
169 	case ETH_SS_STATS:
170 		return ARRAY_SIZE(ethtool_stats_keys) +
171 		       VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
172 		       VETH_TQ_STATS_LEN * dev->real_num_tx_queues +
173 		       page_pool_ethtool_stats_get_count();
174 	default:
175 		return -EOPNOTSUPP;
176 	}
177 }
178 
179 static void veth_get_page_pool_stats(struct net_device *dev, u64 *data)
180 {
181 #ifdef CONFIG_PAGE_POOL_STATS
182 	struct veth_priv *priv = netdev_priv(dev);
183 	struct page_pool_stats pp_stats = {};
184 	int i;
185 
186 	for (i = 0; i < dev->real_num_rx_queues; i++) {
187 		if (!priv->rq[i].page_pool)
188 			continue;
189 		page_pool_get_stats(priv->rq[i].page_pool, &pp_stats);
190 	}
191 	page_pool_ethtool_stats_get(data, &pp_stats);
192 #endif /* CONFIG_PAGE_POOL_STATS */
193 }
194 
195 static void veth_get_ethtool_stats(struct net_device *dev,
196 		struct ethtool_stats *stats, u64 *data)
197 {
198 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
199 	struct net_device *peer = rtnl_dereference(priv->peer);
200 	int i, j, idx, pp_idx;
201 
202 	data[0] = peer ? peer->ifindex : 0;
203 	idx = 1;
204 	for (i = 0; i < dev->real_num_rx_queues; i++) {
205 		const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
206 		const void *stats_base = (void *)&rq_stats->vs;
207 		unsigned int start;
208 		size_t offset;
209 
210 		do {
211 			start = u64_stats_fetch_begin(&rq_stats->syncp);
212 			for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
213 				offset = veth_rq_stats_desc[j].offset;
214 				data[idx + j] = *(u64 *)(stats_base + offset);
215 			}
216 		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
217 		idx += VETH_RQ_STATS_LEN;
218 	}
219 	pp_idx = idx;
220 
221 	if (!peer)
222 		goto page_pool_stats;
223 
224 	rcv_priv = netdev_priv(peer);
225 	for (i = 0; i < peer->real_num_rx_queues; i++) {
226 		const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
227 		const void *base = (void *)&rq_stats->vs;
228 		unsigned int start, tx_idx = idx;
229 		size_t offset;
230 
231 		tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
232 		do {
233 			start = u64_stats_fetch_begin(&rq_stats->syncp);
234 			for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
235 				offset = veth_tq_stats_desc[j].offset;
236 				data[tx_idx + j] += *(u64 *)(base + offset);
237 			}
238 		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
239 		pp_idx = tx_idx + VETH_TQ_STATS_LEN;
240 	}
241 
242 page_pool_stats:
243 	veth_get_page_pool_stats(dev, &data[pp_idx]);
244 }
245 
246 static void veth_get_channels(struct net_device *dev,
247 			      struct ethtool_channels *channels)
248 {
249 	channels->tx_count = dev->real_num_tx_queues;
250 	channels->rx_count = dev->real_num_rx_queues;
251 	channels->max_tx = dev->num_tx_queues;
252 	channels->max_rx = dev->num_rx_queues;
253 }
254 
255 static int veth_set_channels(struct net_device *dev,
256 			     struct ethtool_channels *ch);
257 
258 static const struct ethtool_ops veth_ethtool_ops = {
259 	.get_drvinfo		= veth_get_drvinfo,
260 	.get_link		= ethtool_op_get_link,
261 	.get_strings		= veth_get_strings,
262 	.get_sset_count		= veth_get_sset_count,
263 	.get_ethtool_stats	= veth_get_ethtool_stats,
264 	.get_link_ksettings	= veth_get_link_ksettings,
265 	.get_ts_info		= ethtool_op_get_ts_info,
266 	.get_channels		= veth_get_channels,
267 	.set_channels		= veth_set_channels,
268 };
269 
270 /* general routines */
271 
272 static bool veth_is_xdp_frame(void *ptr)
273 {
274 	return (unsigned long)ptr & VETH_XDP_FLAG;
275 }
276 
277 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
278 {
279 	return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
280 }
281 
282 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
283 {
284 	return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
285 }
286 
287 static void veth_ptr_free(void *ptr)
288 {
289 	if (veth_is_xdp_frame(ptr))
290 		xdp_return_frame(veth_ptr_to_xdp(ptr));
291 	else
292 		kfree_skb(ptr);
293 }
294 
295 static void __veth_xdp_flush(struct veth_rq *rq)
296 {
297 	/* Write ptr_ring before reading rx_notify_masked */
298 	smp_mb();
299 	if (!READ_ONCE(rq->rx_notify_masked) &&
300 	    napi_schedule_prep(&rq->xdp_napi)) {
301 		WRITE_ONCE(rq->rx_notify_masked, true);
302 		__napi_schedule(&rq->xdp_napi);
303 	}
304 }
305 
306 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
307 {
308 	if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
309 		dev_kfree_skb_any(skb);
310 		return NET_RX_DROP;
311 	}
312 
313 	return NET_RX_SUCCESS;
314 }
315 
316 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
317 			    struct veth_rq *rq, bool xdp)
318 {
319 	return __dev_forward_skb(dev, skb) ?: xdp ?
320 		veth_xdp_rx(rq, skb) :
321 		__netif_rx(skb);
322 }
323 
324 /* return true if the specified skb has chances of GRO aggregation
325  * Don't strive for accuracy, but try to avoid GRO overhead in the most
326  * common scenarios.
327  * When XDP is enabled, all traffic is considered eligible, as the xmit
328  * device has TSO off.
329  * When TSO is enabled on the xmit device, we are likely interested only
330  * in UDP aggregation, explicitly check for that if the skb is suspected
331  * - the sock_wfree destructor is used by UDP, ICMP and XDP sockets -
332  * to belong to locally generated UDP traffic.
333  */
334 static bool veth_skb_is_eligible_for_gro(const struct net_device *dev,
335 					 const struct net_device *rcv,
336 					 const struct sk_buff *skb)
337 {
338 	return !(dev->features & NETIF_F_ALL_TSO) ||
339 		(skb->destructor == sock_wfree &&
340 		 rcv->features & (NETIF_F_GRO_FRAGLIST | NETIF_F_GRO_UDP_FWD));
341 }
342 
343 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
344 {
345 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
346 	struct veth_rq *rq = NULL;
347 	struct net_device *rcv;
348 	int length = skb->len;
349 	bool use_napi = false;
350 	int rxq;
351 
352 	rcu_read_lock();
353 	rcv = rcu_dereference(priv->peer);
354 	if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
355 		kfree_skb(skb);
356 		goto drop;
357 	}
358 
359 	rcv_priv = netdev_priv(rcv);
360 	rxq = skb_get_queue_mapping(skb);
361 	if (rxq < rcv->real_num_rx_queues) {
362 		rq = &rcv_priv->rq[rxq];
363 
364 		/* The napi pointer is available when an XDP program is
365 		 * attached or when GRO is enabled
366 		 * Don't bother with napi/GRO if the skb can't be aggregated
367 		 */
368 		use_napi = rcu_access_pointer(rq->napi) &&
369 			   veth_skb_is_eligible_for_gro(dev, rcv, skb);
370 	}
371 
372 	skb_tx_timestamp(skb);
373 	if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
374 		if (!use_napi)
375 			dev_lstats_add(dev, length);
376 	} else {
377 drop:
378 		atomic64_inc(&priv->dropped);
379 	}
380 
381 	if (use_napi)
382 		__veth_xdp_flush(rq);
383 
384 	rcu_read_unlock();
385 
386 	return NETDEV_TX_OK;
387 }
388 
389 static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
390 {
391 	struct veth_priv *priv = netdev_priv(dev);
392 
393 	dev_lstats_read(dev, packets, bytes);
394 	return atomic64_read(&priv->dropped);
395 }
396 
397 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
398 {
399 	struct veth_priv *priv = netdev_priv(dev);
400 	int i;
401 
402 	result->peer_tq_xdp_xmit_err = 0;
403 	result->xdp_packets = 0;
404 	result->xdp_tx_err = 0;
405 	result->xdp_bytes = 0;
406 	result->rx_drops = 0;
407 	for (i = 0; i < dev->num_rx_queues; i++) {
408 		u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
409 		struct veth_rq_stats *stats = &priv->rq[i].stats;
410 		unsigned int start;
411 
412 		do {
413 			start = u64_stats_fetch_begin(&stats->syncp);
414 			peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
415 			xdp_tx_err = stats->vs.xdp_tx_err;
416 			packets = stats->vs.xdp_packets;
417 			bytes = stats->vs.xdp_bytes;
418 			drops = stats->vs.rx_drops;
419 		} while (u64_stats_fetch_retry(&stats->syncp, start));
420 		result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
421 		result->xdp_tx_err += xdp_tx_err;
422 		result->xdp_packets += packets;
423 		result->xdp_bytes += bytes;
424 		result->rx_drops += drops;
425 	}
426 }
427 
428 static void veth_get_stats64(struct net_device *dev,
429 			     struct rtnl_link_stats64 *tot)
430 {
431 	struct veth_priv *priv = netdev_priv(dev);
432 	struct net_device *peer;
433 	struct veth_stats rx;
434 	u64 packets, bytes;
435 
436 	tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
437 	tot->tx_bytes = bytes;
438 	tot->tx_packets = packets;
439 
440 	veth_stats_rx(&rx, dev);
441 	tot->tx_dropped += rx.xdp_tx_err;
442 	tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
443 	tot->rx_bytes = rx.xdp_bytes;
444 	tot->rx_packets = rx.xdp_packets;
445 
446 	rcu_read_lock();
447 	peer = rcu_dereference(priv->peer);
448 	if (peer) {
449 		veth_stats_tx(peer, &packets, &bytes);
450 		tot->rx_bytes += bytes;
451 		tot->rx_packets += packets;
452 
453 		veth_stats_rx(&rx, peer);
454 		tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
455 		tot->rx_dropped += rx.xdp_tx_err;
456 		tot->tx_bytes += rx.xdp_bytes;
457 		tot->tx_packets += rx.xdp_packets;
458 	}
459 	rcu_read_unlock();
460 }
461 
462 /* fake multicast ability */
463 static void veth_set_multicast_list(struct net_device *dev)
464 {
465 }
466 
467 static int veth_select_rxq(struct net_device *dev)
468 {
469 	return smp_processor_id() % dev->real_num_rx_queues;
470 }
471 
472 static struct net_device *veth_peer_dev(struct net_device *dev)
473 {
474 	struct veth_priv *priv = netdev_priv(dev);
475 
476 	/* Callers must be under RCU read side. */
477 	return rcu_dereference(priv->peer);
478 }
479 
480 static int veth_xdp_xmit(struct net_device *dev, int n,
481 			 struct xdp_frame **frames,
482 			 u32 flags, bool ndo_xmit)
483 {
484 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
485 	int i, ret = -ENXIO, nxmit = 0;
486 	struct net_device *rcv;
487 	unsigned int max_len;
488 	struct veth_rq *rq;
489 
490 	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
491 		return -EINVAL;
492 
493 	rcu_read_lock();
494 	rcv = rcu_dereference(priv->peer);
495 	if (unlikely(!rcv))
496 		goto out;
497 
498 	rcv_priv = netdev_priv(rcv);
499 	rq = &rcv_priv->rq[veth_select_rxq(rcv)];
500 	/* The napi pointer is set if NAPI is enabled, which ensures that
501 	 * xdp_ring is initialized on receive side and the peer device is up.
502 	 */
503 	if (!rcu_access_pointer(rq->napi))
504 		goto out;
505 
506 	max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
507 
508 	spin_lock(&rq->xdp_ring.producer_lock);
509 	for (i = 0; i < n; i++) {
510 		struct xdp_frame *frame = frames[i];
511 		void *ptr = veth_xdp_to_ptr(frame);
512 
513 		if (unlikely(xdp_get_frame_len(frame) > max_len ||
514 			     __ptr_ring_produce(&rq->xdp_ring, ptr)))
515 			break;
516 		nxmit++;
517 	}
518 	spin_unlock(&rq->xdp_ring.producer_lock);
519 
520 	if (flags & XDP_XMIT_FLUSH)
521 		__veth_xdp_flush(rq);
522 
523 	ret = nxmit;
524 	if (ndo_xmit) {
525 		u64_stats_update_begin(&rq->stats.syncp);
526 		rq->stats.vs.peer_tq_xdp_xmit += nxmit;
527 		rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
528 		u64_stats_update_end(&rq->stats.syncp);
529 	}
530 
531 out:
532 	rcu_read_unlock();
533 
534 	return ret;
535 }
536 
537 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
538 			     struct xdp_frame **frames, u32 flags)
539 {
540 	int err;
541 
542 	err = veth_xdp_xmit(dev, n, frames, flags, true);
543 	if (err < 0) {
544 		struct veth_priv *priv = netdev_priv(dev);
545 
546 		atomic64_add(n, &priv->dropped);
547 	}
548 
549 	return err;
550 }
551 
552 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
553 {
554 	int sent, i, err = 0, drops;
555 
556 	sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
557 	if (sent < 0) {
558 		err = sent;
559 		sent = 0;
560 	}
561 
562 	for (i = sent; unlikely(i < bq->count); i++)
563 		xdp_return_frame(bq->q[i]);
564 
565 	drops = bq->count - sent;
566 	trace_xdp_bulk_tx(rq->dev, sent, drops, err);
567 
568 	u64_stats_update_begin(&rq->stats.syncp);
569 	rq->stats.vs.xdp_tx += sent;
570 	rq->stats.vs.xdp_tx_err += drops;
571 	u64_stats_update_end(&rq->stats.syncp);
572 
573 	bq->count = 0;
574 }
575 
576 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
577 {
578 	struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
579 	struct net_device *rcv;
580 	struct veth_rq *rcv_rq;
581 
582 	rcu_read_lock();
583 	veth_xdp_flush_bq(rq, bq);
584 	rcv = rcu_dereference(priv->peer);
585 	if (unlikely(!rcv))
586 		goto out;
587 
588 	rcv_priv = netdev_priv(rcv);
589 	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
590 	/* xdp_ring is initialized on receive side? */
591 	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
592 		goto out;
593 
594 	__veth_xdp_flush(rcv_rq);
595 out:
596 	rcu_read_unlock();
597 }
598 
599 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
600 		       struct veth_xdp_tx_bq *bq)
601 {
602 	struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
603 
604 	if (unlikely(!frame))
605 		return -EOVERFLOW;
606 
607 	if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
608 		veth_xdp_flush_bq(rq, bq);
609 
610 	bq->q[bq->count++] = frame;
611 
612 	return 0;
613 }
614 
615 static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
616 					  struct xdp_frame *frame,
617 					  struct veth_xdp_tx_bq *bq,
618 					  struct veth_stats *stats)
619 {
620 	struct xdp_frame orig_frame;
621 	struct bpf_prog *xdp_prog;
622 
623 	rcu_read_lock();
624 	xdp_prog = rcu_dereference(rq->xdp_prog);
625 	if (likely(xdp_prog)) {
626 		struct veth_xdp_buff vxbuf;
627 		struct xdp_buff *xdp = &vxbuf.xdp;
628 		u32 act;
629 
630 		xdp_convert_frame_to_buff(frame, xdp);
631 		xdp->rxq = &rq->xdp_rxq;
632 		vxbuf.skb = NULL;
633 
634 		act = bpf_prog_run_xdp(xdp_prog, xdp);
635 
636 		switch (act) {
637 		case XDP_PASS:
638 			if (xdp_update_frame_from_buff(xdp, frame))
639 				goto err_xdp;
640 			break;
641 		case XDP_TX:
642 			orig_frame = *frame;
643 			xdp->rxq->mem = frame->mem;
644 			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
645 				trace_xdp_exception(rq->dev, xdp_prog, act);
646 				frame = &orig_frame;
647 				stats->rx_drops++;
648 				goto err_xdp;
649 			}
650 			stats->xdp_tx++;
651 			rcu_read_unlock();
652 			goto xdp_xmit;
653 		case XDP_REDIRECT:
654 			orig_frame = *frame;
655 			xdp->rxq->mem = frame->mem;
656 			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
657 				frame = &orig_frame;
658 				stats->rx_drops++;
659 				goto err_xdp;
660 			}
661 			stats->xdp_redirect++;
662 			rcu_read_unlock();
663 			goto xdp_xmit;
664 		default:
665 			bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
666 			fallthrough;
667 		case XDP_ABORTED:
668 			trace_xdp_exception(rq->dev, xdp_prog, act);
669 			fallthrough;
670 		case XDP_DROP:
671 			stats->xdp_drops++;
672 			goto err_xdp;
673 		}
674 	}
675 	rcu_read_unlock();
676 
677 	return frame;
678 err_xdp:
679 	rcu_read_unlock();
680 	xdp_return_frame(frame);
681 xdp_xmit:
682 	return NULL;
683 }
684 
685 /* frames array contains VETH_XDP_BATCH at most */
686 static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
687 				  int n_xdpf, struct veth_xdp_tx_bq *bq,
688 				  struct veth_stats *stats)
689 {
690 	void *skbs[VETH_XDP_BATCH];
691 	int i;
692 
693 	if (xdp_alloc_skb_bulk(skbs, n_xdpf,
694 			       GFP_ATOMIC | __GFP_ZERO) < 0) {
695 		for (i = 0; i < n_xdpf; i++)
696 			xdp_return_frame(frames[i]);
697 		stats->rx_drops += n_xdpf;
698 
699 		return;
700 	}
701 
702 	for (i = 0; i < n_xdpf; i++) {
703 		struct sk_buff *skb = skbs[i];
704 
705 		skb = __xdp_build_skb_from_frame(frames[i], skb,
706 						 rq->dev);
707 		if (!skb) {
708 			xdp_return_frame(frames[i]);
709 			stats->rx_drops++;
710 			continue;
711 		}
712 		napi_gro_receive(&rq->xdp_napi, skb);
713 	}
714 }
715 
716 static void veth_xdp_get(struct xdp_buff *xdp)
717 {
718 	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
719 	int i;
720 
721 	get_page(virt_to_page(xdp->data));
722 	if (likely(!xdp_buff_has_frags(xdp)))
723 		return;
724 
725 	for (i = 0; i < sinfo->nr_frags; i++)
726 		__skb_frag_ref(&sinfo->frags[i]);
727 }
728 
729 static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
730 					struct xdp_buff *xdp,
731 					struct sk_buff **pskb)
732 {
733 	struct sk_buff *skb = *pskb;
734 	u32 frame_sz;
735 
736 	if (skb_shared(skb) || skb_head_is_locked(skb) ||
737 	    skb_shinfo(skb)->nr_frags ||
738 	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
739 		u32 size, len, max_head_size, off;
740 		struct sk_buff *nskb;
741 		struct page *page;
742 		int i, head_off;
743 
744 		/* We need a private copy of the skb and data buffers since
745 		 * the ebpf program can modify it. We segment the original skb
746 		 * into order-0 pages without linearize it.
747 		 *
748 		 * Make sure we have enough space for linear and paged area
749 		 */
750 		max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
751 						  VETH_XDP_HEADROOM);
752 		if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
753 			goto drop;
754 
755 		/* Allocate skb head */
756 		page = page_pool_dev_alloc_pages(rq->page_pool);
757 		if (!page)
758 			goto drop;
759 
760 		nskb = napi_build_skb(page_address(page), PAGE_SIZE);
761 		if (!nskb) {
762 			page_pool_put_full_page(rq->page_pool, page, true);
763 			goto drop;
764 		}
765 
766 		skb_reserve(nskb, VETH_XDP_HEADROOM);
767 		skb_copy_header(nskb, skb);
768 		skb_mark_for_recycle(nskb);
769 
770 		size = min_t(u32, skb->len, max_head_size);
771 		if (skb_copy_bits(skb, 0, nskb->data, size)) {
772 			consume_skb(nskb);
773 			goto drop;
774 		}
775 		skb_put(nskb, size);
776 
777 		head_off = skb_headroom(nskb) - skb_headroom(skb);
778 		skb_headers_offset_update(nskb, head_off);
779 
780 		/* Allocate paged area of new skb */
781 		off = size;
782 		len = skb->len - off;
783 
784 		for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
785 			page = page_pool_dev_alloc_pages(rq->page_pool);
786 			if (!page) {
787 				consume_skb(nskb);
788 				goto drop;
789 			}
790 
791 			size = min_t(u32, len, PAGE_SIZE);
792 			skb_add_rx_frag(nskb, i, page, 0, size, PAGE_SIZE);
793 			if (skb_copy_bits(skb, off, page_address(page),
794 					  size)) {
795 				consume_skb(nskb);
796 				goto drop;
797 			}
798 
799 			len -= size;
800 			off += size;
801 		}
802 
803 		consume_skb(skb);
804 		skb = nskb;
805 	}
806 
807 	/* SKB "head" area always have tailroom for skb_shared_info */
808 	frame_sz = skb_end_pointer(skb) - skb->head;
809 	frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
810 	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
811 	xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
812 			 skb_headlen(skb), true);
813 
814 	if (skb_is_nonlinear(skb)) {
815 		skb_shinfo(skb)->xdp_frags_size = skb->data_len;
816 		xdp_buff_set_frags_flag(xdp);
817 	} else {
818 		xdp_buff_clear_frags_flag(xdp);
819 	}
820 	*pskb = skb;
821 
822 	return 0;
823 drop:
824 	consume_skb(skb);
825 	*pskb = NULL;
826 
827 	return -ENOMEM;
828 }
829 
830 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
831 					struct sk_buff *skb,
832 					struct veth_xdp_tx_bq *bq,
833 					struct veth_stats *stats)
834 {
835 	void *orig_data, *orig_data_end;
836 	struct bpf_prog *xdp_prog;
837 	struct veth_xdp_buff vxbuf;
838 	struct xdp_buff *xdp = &vxbuf.xdp;
839 	u32 act, metalen;
840 	int off;
841 
842 	skb_prepare_for_gro(skb);
843 
844 	rcu_read_lock();
845 	xdp_prog = rcu_dereference(rq->xdp_prog);
846 	if (unlikely(!xdp_prog)) {
847 		rcu_read_unlock();
848 		goto out;
849 	}
850 
851 	__skb_push(skb, skb->data - skb_mac_header(skb));
852 	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
853 		goto drop;
854 	vxbuf.skb = skb;
855 
856 	orig_data = xdp->data;
857 	orig_data_end = xdp->data_end;
858 
859 	act = bpf_prog_run_xdp(xdp_prog, xdp);
860 
861 	switch (act) {
862 	case XDP_PASS:
863 		break;
864 	case XDP_TX:
865 		veth_xdp_get(xdp);
866 		consume_skb(skb);
867 		xdp->rxq->mem = rq->xdp_mem;
868 		if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
869 			trace_xdp_exception(rq->dev, xdp_prog, act);
870 			stats->rx_drops++;
871 			goto err_xdp;
872 		}
873 		stats->xdp_tx++;
874 		rcu_read_unlock();
875 		goto xdp_xmit;
876 	case XDP_REDIRECT:
877 		veth_xdp_get(xdp);
878 		consume_skb(skb);
879 		xdp->rxq->mem = rq->xdp_mem;
880 		if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
881 			stats->rx_drops++;
882 			goto err_xdp;
883 		}
884 		stats->xdp_redirect++;
885 		rcu_read_unlock();
886 		goto xdp_xmit;
887 	default:
888 		bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
889 		fallthrough;
890 	case XDP_ABORTED:
891 		trace_xdp_exception(rq->dev, xdp_prog, act);
892 		fallthrough;
893 	case XDP_DROP:
894 		stats->xdp_drops++;
895 		goto xdp_drop;
896 	}
897 	rcu_read_unlock();
898 
899 	/* check if bpf_xdp_adjust_head was used */
900 	off = orig_data - xdp->data;
901 	if (off > 0)
902 		__skb_push(skb, off);
903 	else if (off < 0)
904 		__skb_pull(skb, -off);
905 
906 	skb_reset_mac_header(skb);
907 
908 	/* check if bpf_xdp_adjust_tail was used */
909 	off = xdp->data_end - orig_data_end;
910 	if (off != 0)
911 		__skb_put(skb, off); /* positive on grow, negative on shrink */
912 
913 	/* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
914 	 * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
915 	 */
916 	if (xdp_buff_has_frags(xdp))
917 		skb->data_len = skb_shinfo(skb)->xdp_frags_size;
918 	else
919 		skb->data_len = 0;
920 
921 	skb->protocol = eth_type_trans(skb, rq->dev);
922 
923 	metalen = xdp->data - xdp->data_meta;
924 	if (metalen)
925 		skb_metadata_set(skb, metalen);
926 out:
927 	return skb;
928 drop:
929 	stats->rx_drops++;
930 xdp_drop:
931 	rcu_read_unlock();
932 	kfree_skb(skb);
933 	return NULL;
934 err_xdp:
935 	rcu_read_unlock();
936 	xdp_return_buff(xdp);
937 xdp_xmit:
938 	return NULL;
939 }
940 
941 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
942 			struct veth_xdp_tx_bq *bq,
943 			struct veth_stats *stats)
944 {
945 	int i, done = 0, n_xdpf = 0;
946 	void *xdpf[VETH_XDP_BATCH];
947 
948 	for (i = 0; i < budget; i++) {
949 		void *ptr = __ptr_ring_consume(&rq->xdp_ring);
950 
951 		if (!ptr)
952 			break;
953 
954 		if (veth_is_xdp_frame(ptr)) {
955 			/* ndo_xdp_xmit */
956 			struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
957 
958 			stats->xdp_bytes += xdp_get_frame_len(frame);
959 			frame = veth_xdp_rcv_one(rq, frame, bq, stats);
960 			if (frame) {
961 				/* XDP_PASS */
962 				xdpf[n_xdpf++] = frame;
963 				if (n_xdpf == VETH_XDP_BATCH) {
964 					veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
965 							      bq, stats);
966 					n_xdpf = 0;
967 				}
968 			}
969 		} else {
970 			/* ndo_start_xmit */
971 			struct sk_buff *skb = ptr;
972 
973 			stats->xdp_bytes += skb->len;
974 			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
975 			if (skb) {
976 				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
977 					netif_receive_skb(skb);
978 				else
979 					napi_gro_receive(&rq->xdp_napi, skb);
980 			}
981 		}
982 		done++;
983 	}
984 
985 	if (n_xdpf)
986 		veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
987 
988 	u64_stats_update_begin(&rq->stats.syncp);
989 	rq->stats.vs.xdp_redirect += stats->xdp_redirect;
990 	rq->stats.vs.xdp_bytes += stats->xdp_bytes;
991 	rq->stats.vs.xdp_drops += stats->xdp_drops;
992 	rq->stats.vs.rx_drops += stats->rx_drops;
993 	rq->stats.vs.xdp_packets += done;
994 	u64_stats_update_end(&rq->stats.syncp);
995 
996 	return done;
997 }
998 
999 static int veth_poll(struct napi_struct *napi, int budget)
1000 {
1001 	struct veth_rq *rq =
1002 		container_of(napi, struct veth_rq, xdp_napi);
1003 	struct veth_stats stats = {};
1004 	struct veth_xdp_tx_bq bq;
1005 	int done;
1006 
1007 	bq.count = 0;
1008 
1009 	xdp_set_return_frame_no_direct();
1010 	done = veth_xdp_rcv(rq, budget, &bq, &stats);
1011 
1012 	if (stats.xdp_redirect > 0)
1013 		xdp_do_flush();
1014 
1015 	if (done < budget && napi_complete_done(napi, done)) {
1016 		/* Write rx_notify_masked before reading ptr_ring */
1017 		smp_store_mb(rq->rx_notify_masked, false);
1018 		if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
1019 			if (napi_schedule_prep(&rq->xdp_napi)) {
1020 				WRITE_ONCE(rq->rx_notify_masked, true);
1021 				__napi_schedule(&rq->xdp_napi);
1022 			}
1023 		}
1024 	}
1025 
1026 	if (stats.xdp_tx > 0)
1027 		veth_xdp_flush(rq, &bq);
1028 	xdp_clear_return_frame_no_direct();
1029 
1030 	return done;
1031 }
1032 
1033 static int veth_create_page_pool(struct veth_rq *rq)
1034 {
1035 	struct page_pool_params pp_params = {
1036 		.order = 0,
1037 		.pool_size = VETH_RING_SIZE,
1038 		.nid = NUMA_NO_NODE,
1039 		.dev = &rq->dev->dev,
1040 	};
1041 
1042 	rq->page_pool = page_pool_create(&pp_params);
1043 	if (IS_ERR(rq->page_pool)) {
1044 		int err = PTR_ERR(rq->page_pool);
1045 
1046 		rq->page_pool = NULL;
1047 		return err;
1048 	}
1049 
1050 	return 0;
1051 }
1052 
1053 static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
1054 {
1055 	struct veth_priv *priv = netdev_priv(dev);
1056 	int err, i;
1057 
1058 	for (i = start; i < end; i++) {
1059 		err = veth_create_page_pool(&priv->rq[i]);
1060 		if (err)
1061 			goto err_page_pool;
1062 	}
1063 
1064 	for (i = start; i < end; i++) {
1065 		struct veth_rq *rq = &priv->rq[i];
1066 
1067 		err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
1068 		if (err)
1069 			goto err_xdp_ring;
1070 	}
1071 
1072 	for (i = start; i < end; i++) {
1073 		struct veth_rq *rq = &priv->rq[i];
1074 
1075 		napi_enable(&rq->xdp_napi);
1076 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1077 	}
1078 
1079 	return 0;
1080 
1081 err_xdp_ring:
1082 	for (i--; i >= start; i--)
1083 		ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
1084 err_page_pool:
1085 	for (i = start; i < end; i++) {
1086 		page_pool_destroy(priv->rq[i].page_pool);
1087 		priv->rq[i].page_pool = NULL;
1088 	}
1089 
1090 	return err;
1091 }
1092 
1093 static int __veth_napi_enable(struct net_device *dev)
1094 {
1095 	return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1096 }
1097 
1098 static void veth_napi_del_range(struct net_device *dev, int start, int end)
1099 {
1100 	struct veth_priv *priv = netdev_priv(dev);
1101 	int i;
1102 
1103 	for (i = start; i < end; i++) {
1104 		struct veth_rq *rq = &priv->rq[i];
1105 
1106 		rcu_assign_pointer(priv->rq[i].napi, NULL);
1107 		napi_disable(&rq->xdp_napi);
1108 		__netif_napi_del(&rq->xdp_napi);
1109 	}
1110 	synchronize_net();
1111 
1112 	for (i = start; i < end; i++) {
1113 		struct veth_rq *rq = &priv->rq[i];
1114 
1115 		rq->rx_notify_masked = false;
1116 		ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
1117 	}
1118 
1119 	for (i = start; i < end; i++) {
1120 		page_pool_destroy(priv->rq[i].page_pool);
1121 		priv->rq[i].page_pool = NULL;
1122 	}
1123 }
1124 
1125 static void veth_napi_del(struct net_device *dev)
1126 {
1127 	veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
1128 }
1129 
1130 static bool veth_gro_requested(const struct net_device *dev)
1131 {
1132 	return !!(dev->wanted_features & NETIF_F_GRO);
1133 }
1134 
1135 static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
1136 				 bool napi_already_on)
1137 {
1138 	struct veth_priv *priv = netdev_priv(dev);
1139 	int err, i;
1140 
1141 	for (i = start; i < end; i++) {
1142 		struct veth_rq *rq = &priv->rq[i];
1143 
1144 		if (!napi_already_on)
1145 			netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1146 		err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
1147 		if (err < 0)
1148 			goto err_rxq_reg;
1149 
1150 		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
1151 						 MEM_TYPE_PAGE_SHARED,
1152 						 NULL);
1153 		if (err < 0)
1154 			goto err_reg_mem;
1155 
1156 		/* Save original mem info as it can be overwritten */
1157 		rq->xdp_mem = rq->xdp_rxq.mem;
1158 	}
1159 	return 0;
1160 
1161 err_reg_mem:
1162 	xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
1163 err_rxq_reg:
1164 	for (i--; i >= start; i--) {
1165 		struct veth_rq *rq = &priv->rq[i];
1166 
1167 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1168 		if (!napi_already_on)
1169 			netif_napi_del(&rq->xdp_napi);
1170 	}
1171 
1172 	return err;
1173 }
1174 
1175 static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
1176 				   bool delete_napi)
1177 {
1178 	struct veth_priv *priv = netdev_priv(dev);
1179 	int i;
1180 
1181 	for (i = start; i < end; i++) {
1182 		struct veth_rq *rq = &priv->rq[i];
1183 
1184 		rq->xdp_rxq.mem = rq->xdp_mem;
1185 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1186 
1187 		if (delete_napi)
1188 			netif_napi_del(&rq->xdp_napi);
1189 	}
1190 }
1191 
1192 static int veth_enable_xdp(struct net_device *dev)
1193 {
1194 	bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
1195 	struct veth_priv *priv = netdev_priv(dev);
1196 	int err, i;
1197 
1198 	if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
1199 		err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
1200 		if (err)
1201 			return err;
1202 
1203 		if (!napi_already_on) {
1204 			err = __veth_napi_enable(dev);
1205 			if (err) {
1206 				veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
1207 				return err;
1208 			}
1209 
1210 			if (!veth_gro_requested(dev)) {
1211 				/* user-space did not require GRO, but adding XDP
1212 				 * is supposed to get GRO working
1213 				 */
1214 				dev->features |= NETIF_F_GRO;
1215 				netdev_features_change(dev);
1216 			}
1217 		}
1218 	}
1219 
1220 	for (i = 0; i < dev->real_num_rx_queues; i++) {
1221 		rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
1222 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1223 	}
1224 
1225 	return 0;
1226 }
1227 
1228 static void veth_disable_xdp(struct net_device *dev)
1229 {
1230 	struct veth_priv *priv = netdev_priv(dev);
1231 	int i;
1232 
1233 	for (i = 0; i < dev->real_num_rx_queues; i++)
1234 		rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
1235 
1236 	if (!netif_running(dev) || !veth_gro_requested(dev)) {
1237 		veth_napi_del(dev);
1238 
1239 		/* if user-space did not require GRO, since adding XDP
1240 		 * enabled it, clear it now
1241 		 */
1242 		if (!veth_gro_requested(dev) && netif_running(dev)) {
1243 			dev->features &= ~NETIF_F_GRO;
1244 			netdev_features_change(dev);
1245 		}
1246 	}
1247 
1248 	veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
1249 }
1250 
1251 static int veth_napi_enable_range(struct net_device *dev, int start, int end)
1252 {
1253 	struct veth_priv *priv = netdev_priv(dev);
1254 	int err, i;
1255 
1256 	for (i = start; i < end; i++) {
1257 		struct veth_rq *rq = &priv->rq[i];
1258 
1259 		netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1260 	}
1261 
1262 	err = __veth_napi_enable_range(dev, start, end);
1263 	if (err) {
1264 		for (i = start; i < end; i++) {
1265 			struct veth_rq *rq = &priv->rq[i];
1266 
1267 			netif_napi_del(&rq->xdp_napi);
1268 		}
1269 		return err;
1270 	}
1271 	return err;
1272 }
1273 
1274 static int veth_napi_enable(struct net_device *dev)
1275 {
1276 	return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1277 }
1278 
1279 static void veth_disable_range_safe(struct net_device *dev, int start, int end)
1280 {
1281 	struct veth_priv *priv = netdev_priv(dev);
1282 
1283 	if (start >= end)
1284 		return;
1285 
1286 	if (priv->_xdp_prog) {
1287 		veth_napi_del_range(dev, start, end);
1288 		veth_disable_xdp_range(dev, start, end, false);
1289 	} else if (veth_gro_requested(dev)) {
1290 		veth_napi_del_range(dev, start, end);
1291 	}
1292 }
1293 
1294 static int veth_enable_range_safe(struct net_device *dev, int start, int end)
1295 {
1296 	struct veth_priv *priv = netdev_priv(dev);
1297 	int err;
1298 
1299 	if (start >= end)
1300 		return 0;
1301 
1302 	if (priv->_xdp_prog) {
1303 		/* these channels are freshly initialized, napi is not on there even
1304 		 * when GRO is requeste
1305 		 */
1306 		err = veth_enable_xdp_range(dev, start, end, false);
1307 		if (err)
1308 			return err;
1309 
1310 		err = __veth_napi_enable_range(dev, start, end);
1311 		if (err) {
1312 			/* on error always delete the newly added napis */
1313 			veth_disable_xdp_range(dev, start, end, true);
1314 			return err;
1315 		}
1316 	} else if (veth_gro_requested(dev)) {
1317 		return veth_napi_enable_range(dev, start, end);
1318 	}
1319 	return 0;
1320 }
1321 
1322 static void veth_set_xdp_features(struct net_device *dev)
1323 {
1324 	struct veth_priv *priv = netdev_priv(dev);
1325 	struct net_device *peer;
1326 
1327 	peer = rtnl_dereference(priv->peer);
1328 	if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
1329 		struct veth_priv *priv_peer = netdev_priv(peer);
1330 		xdp_features_t val = NETDEV_XDP_ACT_BASIC |
1331 				     NETDEV_XDP_ACT_REDIRECT |
1332 				     NETDEV_XDP_ACT_RX_SG;
1333 
1334 		if (priv_peer->_xdp_prog || veth_gro_requested(peer))
1335 			val |= NETDEV_XDP_ACT_NDO_XMIT |
1336 			       NETDEV_XDP_ACT_NDO_XMIT_SG;
1337 		xdp_set_features_flag(dev, val);
1338 	} else {
1339 		xdp_clear_features_flag(dev);
1340 	}
1341 }
1342 
1343 static int veth_set_channels(struct net_device *dev,
1344 			     struct ethtool_channels *ch)
1345 {
1346 	struct veth_priv *priv = netdev_priv(dev);
1347 	unsigned int old_rx_count, new_rx_count;
1348 	struct veth_priv *peer_priv;
1349 	struct net_device *peer;
1350 	int err;
1351 
1352 	/* sanity check. Upper bounds are already enforced by the caller */
1353 	if (!ch->rx_count || !ch->tx_count)
1354 		return -EINVAL;
1355 
1356 	/* avoid braking XDP, if that is enabled */
1357 	peer = rtnl_dereference(priv->peer);
1358 	peer_priv = peer ? netdev_priv(peer) : NULL;
1359 	if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
1360 		return -EINVAL;
1361 
1362 	if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
1363 		return -EINVAL;
1364 
1365 	old_rx_count = dev->real_num_rx_queues;
1366 	new_rx_count = ch->rx_count;
1367 	if (netif_running(dev)) {
1368 		/* turn device off */
1369 		netif_carrier_off(dev);
1370 		if (peer)
1371 			netif_carrier_off(peer);
1372 
1373 		/* try to allocate new resurces, as needed*/
1374 		err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
1375 		if (err)
1376 			goto out;
1377 	}
1378 
1379 	err = netif_set_real_num_rx_queues(dev, ch->rx_count);
1380 	if (err)
1381 		goto revert;
1382 
1383 	err = netif_set_real_num_tx_queues(dev, ch->tx_count);
1384 	if (err) {
1385 		int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
1386 
1387 		/* this error condition could happen only if rx and tx change
1388 		 * in opposite directions (e.g. tx nr raises, rx nr decreases)
1389 		 * and we can't do anything to fully restore the original
1390 		 * status
1391 		 */
1392 		if (err2)
1393 			pr_warn("Can't restore rx queues config %d -> %d %d",
1394 				new_rx_count, old_rx_count, err2);
1395 		else
1396 			goto revert;
1397 	}
1398 
1399 out:
1400 	if (netif_running(dev)) {
1401 		/* note that we need to swap the arguments WRT the enable part
1402 		 * to identify the range we have to disable
1403 		 */
1404 		veth_disable_range_safe(dev, new_rx_count, old_rx_count);
1405 		netif_carrier_on(dev);
1406 		if (peer)
1407 			netif_carrier_on(peer);
1408 	}
1409 
1410 	/* update XDP supported features */
1411 	veth_set_xdp_features(dev);
1412 	if (peer)
1413 		veth_set_xdp_features(peer);
1414 
1415 	return err;
1416 
1417 revert:
1418 	new_rx_count = old_rx_count;
1419 	old_rx_count = ch->rx_count;
1420 	goto out;
1421 }
1422 
1423 static int veth_open(struct net_device *dev)
1424 {
1425 	struct veth_priv *priv = netdev_priv(dev);
1426 	struct net_device *peer = rtnl_dereference(priv->peer);
1427 	int err;
1428 
1429 	if (!peer)
1430 		return -ENOTCONN;
1431 
1432 	if (priv->_xdp_prog) {
1433 		err = veth_enable_xdp(dev);
1434 		if (err)
1435 			return err;
1436 	} else if (veth_gro_requested(dev)) {
1437 		err = veth_napi_enable(dev);
1438 		if (err)
1439 			return err;
1440 	}
1441 
1442 	if (peer->flags & IFF_UP) {
1443 		netif_carrier_on(dev);
1444 		netif_carrier_on(peer);
1445 	}
1446 
1447 	return 0;
1448 }
1449 
1450 static int veth_close(struct net_device *dev)
1451 {
1452 	struct veth_priv *priv = netdev_priv(dev);
1453 	struct net_device *peer = rtnl_dereference(priv->peer);
1454 
1455 	netif_carrier_off(dev);
1456 	if (peer)
1457 		netif_carrier_off(peer);
1458 
1459 	if (priv->_xdp_prog)
1460 		veth_disable_xdp(dev);
1461 	else if (veth_gro_requested(dev))
1462 		veth_napi_del(dev);
1463 
1464 	return 0;
1465 }
1466 
1467 static int is_valid_veth_mtu(int mtu)
1468 {
1469 	return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1470 }
1471 
1472 static int veth_alloc_queues(struct net_device *dev)
1473 {
1474 	struct veth_priv *priv = netdev_priv(dev);
1475 	int i;
1476 
1477 	priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL_ACCOUNT);
1478 	if (!priv->rq)
1479 		return -ENOMEM;
1480 
1481 	for (i = 0; i < dev->num_rx_queues; i++) {
1482 		priv->rq[i].dev = dev;
1483 		u64_stats_init(&priv->rq[i].stats.syncp);
1484 	}
1485 
1486 	return 0;
1487 }
1488 
1489 static void veth_free_queues(struct net_device *dev)
1490 {
1491 	struct veth_priv *priv = netdev_priv(dev);
1492 
1493 	kfree(priv->rq);
1494 }
1495 
1496 static int veth_dev_init(struct net_device *dev)
1497 {
1498 	int err;
1499 
1500 	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
1501 	if (!dev->lstats)
1502 		return -ENOMEM;
1503 
1504 	err = veth_alloc_queues(dev);
1505 	if (err) {
1506 		free_percpu(dev->lstats);
1507 		return err;
1508 	}
1509 
1510 	return 0;
1511 }
1512 
1513 static void veth_dev_free(struct net_device *dev)
1514 {
1515 	veth_free_queues(dev);
1516 	free_percpu(dev->lstats);
1517 }
1518 
1519 #ifdef CONFIG_NET_POLL_CONTROLLER
1520 static void veth_poll_controller(struct net_device *dev)
1521 {
1522 	/* veth only receives frames when its peer sends one
1523 	 * Since it has nothing to do with disabling irqs, we are guaranteed
1524 	 * never to have pending data when we poll for it so
1525 	 * there is nothing to do here.
1526 	 *
1527 	 * We need this though so netpoll recognizes us as an interface that
1528 	 * supports polling, which enables bridge devices in virt setups to
1529 	 * still use netconsole
1530 	 */
1531 }
1532 #endif	/* CONFIG_NET_POLL_CONTROLLER */
1533 
1534 static int veth_get_iflink(const struct net_device *dev)
1535 {
1536 	struct veth_priv *priv = netdev_priv(dev);
1537 	struct net_device *peer;
1538 	int iflink;
1539 
1540 	rcu_read_lock();
1541 	peer = rcu_dereference(priv->peer);
1542 	iflink = peer ? peer->ifindex : 0;
1543 	rcu_read_unlock();
1544 
1545 	return iflink;
1546 }
1547 
1548 static netdev_features_t veth_fix_features(struct net_device *dev,
1549 					   netdev_features_t features)
1550 {
1551 	struct veth_priv *priv = netdev_priv(dev);
1552 	struct net_device *peer;
1553 
1554 	peer = rtnl_dereference(priv->peer);
1555 	if (peer) {
1556 		struct veth_priv *peer_priv = netdev_priv(peer);
1557 
1558 		if (peer_priv->_xdp_prog)
1559 			features &= ~NETIF_F_GSO_SOFTWARE;
1560 	}
1561 	if (priv->_xdp_prog)
1562 		features |= NETIF_F_GRO;
1563 
1564 	return features;
1565 }
1566 
1567 static int veth_set_features(struct net_device *dev,
1568 			     netdev_features_t features)
1569 {
1570 	netdev_features_t changed = features ^ dev->features;
1571 	struct veth_priv *priv = netdev_priv(dev);
1572 	struct net_device *peer;
1573 	int err;
1574 
1575 	if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
1576 		return 0;
1577 
1578 	peer = rtnl_dereference(priv->peer);
1579 	if (features & NETIF_F_GRO) {
1580 		err = veth_napi_enable(dev);
1581 		if (err)
1582 			return err;
1583 
1584 		if (peer)
1585 			xdp_features_set_redirect_target(peer, true);
1586 	} else {
1587 		if (peer)
1588 			xdp_features_clear_redirect_target(peer);
1589 		veth_napi_del(dev);
1590 	}
1591 	return 0;
1592 }
1593 
1594 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1595 {
1596 	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1597 	struct net_device *peer;
1598 
1599 	if (new_hr < 0)
1600 		new_hr = 0;
1601 
1602 	rcu_read_lock();
1603 	peer = rcu_dereference(priv->peer);
1604 	if (unlikely(!peer))
1605 		goto out;
1606 
1607 	peer_priv = netdev_priv(peer);
1608 	priv->requested_headroom = new_hr;
1609 	new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1610 	dev->needed_headroom = new_hr;
1611 	peer->needed_headroom = new_hr;
1612 
1613 out:
1614 	rcu_read_unlock();
1615 }
1616 
1617 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1618 			struct netlink_ext_ack *extack)
1619 {
1620 	struct veth_priv *priv = netdev_priv(dev);
1621 	struct bpf_prog *old_prog;
1622 	struct net_device *peer;
1623 	unsigned int max_mtu;
1624 	int err;
1625 
1626 	old_prog = priv->_xdp_prog;
1627 	priv->_xdp_prog = prog;
1628 	peer = rtnl_dereference(priv->peer);
1629 
1630 	if (prog) {
1631 		if (!peer) {
1632 			NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1633 			err = -ENOTCONN;
1634 			goto err;
1635 		}
1636 
1637 		max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
1638 			  peer->hard_header_len;
1639 		/* Allow increasing the max_mtu if the program supports
1640 		 * XDP fragments.
1641 		 */
1642 		if (prog->aux->xdp_has_frags)
1643 			max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
1644 
1645 		if (peer->mtu > max_mtu) {
1646 			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1647 			err = -ERANGE;
1648 			goto err;
1649 		}
1650 
1651 		if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1652 			NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1653 			err = -ENOSPC;
1654 			goto err;
1655 		}
1656 
1657 		if (dev->flags & IFF_UP) {
1658 			err = veth_enable_xdp(dev);
1659 			if (err) {
1660 				NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1661 				goto err;
1662 			}
1663 		}
1664 
1665 		if (!old_prog) {
1666 			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1667 			peer->max_mtu = max_mtu;
1668 		}
1669 
1670 		xdp_features_set_redirect_target(peer, true);
1671 	}
1672 
1673 	if (old_prog) {
1674 		if (!prog) {
1675 			if (peer && !veth_gro_requested(dev))
1676 				xdp_features_clear_redirect_target(peer);
1677 
1678 			if (dev->flags & IFF_UP)
1679 				veth_disable_xdp(dev);
1680 
1681 			if (peer) {
1682 				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1683 				peer->max_mtu = ETH_MAX_MTU;
1684 			}
1685 		}
1686 		bpf_prog_put(old_prog);
1687 	}
1688 
1689 	if ((!!old_prog ^ !!prog) && peer)
1690 		netdev_update_features(peer);
1691 
1692 	return 0;
1693 err:
1694 	priv->_xdp_prog = old_prog;
1695 
1696 	return err;
1697 }
1698 
1699 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1700 {
1701 	switch (xdp->command) {
1702 	case XDP_SETUP_PROG:
1703 		return veth_xdp_set(dev, xdp->prog, xdp->extack);
1704 	default:
1705 		return -EINVAL;
1706 	}
1707 }
1708 
1709 static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
1710 {
1711 	struct veth_xdp_buff *_ctx = (void *)ctx;
1712 
1713 	if (!_ctx->skb)
1714 		return -ENODATA;
1715 
1716 	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
1717 	return 0;
1718 }
1719 
1720 static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
1721 			    enum xdp_rss_hash_type *rss_type)
1722 {
1723 	struct veth_xdp_buff *_ctx = (void *)ctx;
1724 	struct sk_buff *skb = _ctx->skb;
1725 
1726 	if (!skb)
1727 		return -ENODATA;
1728 
1729 	*hash = skb_get_hash(skb);
1730 	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;
1731 
1732 	return 0;
1733 }
1734 
1735 static const struct net_device_ops veth_netdev_ops = {
1736 	.ndo_init            = veth_dev_init,
1737 	.ndo_open            = veth_open,
1738 	.ndo_stop            = veth_close,
1739 	.ndo_start_xmit      = veth_xmit,
1740 	.ndo_get_stats64     = veth_get_stats64,
1741 	.ndo_set_rx_mode     = veth_set_multicast_list,
1742 	.ndo_set_mac_address = eth_mac_addr,
1743 #ifdef CONFIG_NET_POLL_CONTROLLER
1744 	.ndo_poll_controller	= veth_poll_controller,
1745 #endif
1746 	.ndo_get_iflink		= veth_get_iflink,
1747 	.ndo_fix_features	= veth_fix_features,
1748 	.ndo_set_features	= veth_set_features,
1749 	.ndo_features_check	= passthru_features_check,
1750 	.ndo_set_rx_headroom	= veth_set_rx_headroom,
1751 	.ndo_bpf		= veth_xdp,
1752 	.ndo_xdp_xmit		= veth_ndo_xdp_xmit,
1753 	.ndo_get_peer_dev	= veth_peer_dev,
1754 };
1755 
1756 static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
1757 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
1758 	.xmo_rx_hash			= veth_xdp_rx_hash,
1759 };
1760 
1761 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1762 		       NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1763 		       NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1764 		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1765 		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1766 
1767 static void veth_setup(struct net_device *dev)
1768 {
1769 	ether_setup(dev);
1770 
1771 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1772 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1773 	dev->priv_flags |= IFF_NO_QUEUE;
1774 	dev->priv_flags |= IFF_PHONY_HEADROOM;
1775 
1776 	dev->netdev_ops = &veth_netdev_ops;
1777 	dev->xdp_metadata_ops = &veth_xdp_metadata_ops;
1778 	dev->ethtool_ops = &veth_ethtool_ops;
1779 	dev->features |= NETIF_F_LLTX;
1780 	dev->features |= VETH_FEATURES;
1781 	dev->vlan_features = dev->features &
1782 			     ~(NETIF_F_HW_VLAN_CTAG_TX |
1783 			       NETIF_F_HW_VLAN_STAG_TX |
1784 			       NETIF_F_HW_VLAN_CTAG_RX |
1785 			       NETIF_F_HW_VLAN_STAG_RX);
1786 	dev->needs_free_netdev = true;
1787 	dev->priv_destructor = veth_dev_free;
1788 	dev->max_mtu = ETH_MAX_MTU;
1789 
1790 	dev->hw_features = VETH_FEATURES;
1791 	dev->hw_enc_features = VETH_FEATURES;
1792 	dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1793 	netif_set_tso_max_size(dev, GSO_MAX_SIZE);
1794 }
1795 
1796 /*
1797  * netlink interface
1798  */
1799 
1800 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1801 			 struct netlink_ext_ack *extack)
1802 {
1803 	if (tb[IFLA_ADDRESS]) {
1804 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1805 			return -EINVAL;
1806 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1807 			return -EADDRNOTAVAIL;
1808 	}
1809 	if (tb[IFLA_MTU]) {
1810 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1811 			return -EINVAL;
1812 	}
1813 	return 0;
1814 }
1815 
1816 static struct rtnl_link_ops veth_link_ops;
1817 
1818 static void veth_disable_gro(struct net_device *dev)
1819 {
1820 	dev->features &= ~NETIF_F_GRO;
1821 	dev->wanted_features &= ~NETIF_F_GRO;
1822 	netdev_update_features(dev);
1823 }
1824 
1825 static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
1826 {
1827 	int err;
1828 
1829 	if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
1830 		err = netif_set_real_num_tx_queues(dev, 1);
1831 		if (err)
1832 			return err;
1833 	}
1834 	if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
1835 		err = netif_set_real_num_rx_queues(dev, 1);
1836 		if (err)
1837 			return err;
1838 	}
1839 	return 0;
1840 }
1841 
1842 static int veth_newlink(struct net *src_net, struct net_device *dev,
1843 			struct nlattr *tb[], struct nlattr *data[],
1844 			struct netlink_ext_ack *extack)
1845 {
1846 	int err;
1847 	struct net_device *peer;
1848 	struct veth_priv *priv;
1849 	char ifname[IFNAMSIZ];
1850 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1851 	unsigned char name_assign_type;
1852 	struct ifinfomsg *ifmp;
1853 	struct net *net;
1854 
1855 	/*
1856 	 * create and register peer first
1857 	 */
1858 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1859 		struct nlattr *nla_peer;
1860 
1861 		nla_peer = data[VETH_INFO_PEER];
1862 		ifmp = nla_data(nla_peer);
1863 		err = rtnl_nla_parse_ifla(peer_tb,
1864 					  nla_data(nla_peer) + sizeof(struct ifinfomsg),
1865 					  nla_len(nla_peer) - sizeof(struct ifinfomsg),
1866 					  NULL);
1867 		if (err < 0)
1868 			return err;
1869 
1870 		err = veth_validate(peer_tb, NULL, extack);
1871 		if (err < 0)
1872 			return err;
1873 
1874 		tbp = peer_tb;
1875 	} else {
1876 		ifmp = NULL;
1877 		tbp = tb;
1878 	}
1879 
1880 	if (ifmp && tbp[IFLA_IFNAME]) {
1881 		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1882 		name_assign_type = NET_NAME_USER;
1883 	} else {
1884 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1885 		name_assign_type = NET_NAME_ENUM;
1886 	}
1887 
1888 	net = rtnl_link_get_net(src_net, tbp);
1889 	if (IS_ERR(net))
1890 		return PTR_ERR(net);
1891 
1892 	peer = rtnl_create_link(net, ifname, name_assign_type,
1893 				&veth_link_ops, tbp, extack);
1894 	if (IS_ERR(peer)) {
1895 		put_net(net);
1896 		return PTR_ERR(peer);
1897 	}
1898 
1899 	if (!ifmp || !tbp[IFLA_ADDRESS])
1900 		eth_hw_addr_random(peer);
1901 
1902 	if (ifmp && (dev->ifindex != 0))
1903 		peer->ifindex = ifmp->ifi_index;
1904 
1905 	netif_inherit_tso_max(peer, dev);
1906 
1907 	err = register_netdevice(peer);
1908 	put_net(net);
1909 	net = NULL;
1910 	if (err < 0)
1911 		goto err_register_peer;
1912 
1913 	/* keep GRO disabled by default to be consistent with the established
1914 	 * veth behavior
1915 	 */
1916 	veth_disable_gro(peer);
1917 	netif_carrier_off(peer);
1918 
1919 	err = rtnl_configure_link(peer, ifmp, 0, NULL);
1920 	if (err < 0)
1921 		goto err_configure_peer;
1922 
1923 	/*
1924 	 * register dev last
1925 	 *
1926 	 * note, that since we've registered new device the dev's name
1927 	 * should be re-allocated
1928 	 */
1929 
1930 	if (tb[IFLA_ADDRESS] == NULL)
1931 		eth_hw_addr_random(dev);
1932 
1933 	if (tb[IFLA_IFNAME])
1934 		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1935 	else
1936 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1937 
1938 	err = register_netdevice(dev);
1939 	if (err < 0)
1940 		goto err_register_dev;
1941 
1942 	netif_carrier_off(dev);
1943 
1944 	/*
1945 	 * tie the deviced together
1946 	 */
1947 
1948 	priv = netdev_priv(dev);
1949 	rcu_assign_pointer(priv->peer, peer);
1950 	err = veth_init_queues(dev, tb);
1951 	if (err)
1952 		goto err_queues;
1953 
1954 	priv = netdev_priv(peer);
1955 	rcu_assign_pointer(priv->peer, dev);
1956 	err = veth_init_queues(peer, tb);
1957 	if (err)
1958 		goto err_queues;
1959 
1960 	veth_disable_gro(dev);
1961 	/* update XDP supported features */
1962 	veth_set_xdp_features(dev);
1963 	veth_set_xdp_features(peer);
1964 
1965 	return 0;
1966 
1967 err_queues:
1968 	unregister_netdevice(dev);
1969 err_register_dev:
1970 	/* nothing to do */
1971 err_configure_peer:
1972 	unregister_netdevice(peer);
1973 	return err;
1974 
1975 err_register_peer:
1976 	free_netdev(peer);
1977 	return err;
1978 }
1979 
1980 static void veth_dellink(struct net_device *dev, struct list_head *head)
1981 {
1982 	struct veth_priv *priv;
1983 	struct net_device *peer;
1984 
1985 	priv = netdev_priv(dev);
1986 	peer = rtnl_dereference(priv->peer);
1987 
1988 	/* Note : dellink() is called from default_device_exit_batch(),
1989 	 * before a rcu_synchronize() point. The devices are guaranteed
1990 	 * not being freed before one RCU grace period.
1991 	 */
1992 	RCU_INIT_POINTER(priv->peer, NULL);
1993 	unregister_netdevice_queue(dev, head);
1994 
1995 	if (peer) {
1996 		priv = netdev_priv(peer);
1997 		RCU_INIT_POINTER(priv->peer, NULL);
1998 		unregister_netdevice_queue(peer, head);
1999 	}
2000 }
2001 
2002 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
2003 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
2004 };
2005 
2006 static struct net *veth_get_link_net(const struct net_device *dev)
2007 {
2008 	struct veth_priv *priv = netdev_priv(dev);
2009 	struct net_device *peer = rtnl_dereference(priv->peer);
2010 
2011 	return peer ? dev_net(peer) : dev_net(dev);
2012 }
2013 
2014 static unsigned int veth_get_num_queues(void)
2015 {
2016 	/* enforce the same queue limit as rtnl_create_link */
2017 	int queues = num_possible_cpus();
2018 
2019 	if (queues > 4096)
2020 		queues = 4096;
2021 	return queues;
2022 }
2023 
2024 static struct rtnl_link_ops veth_link_ops = {
2025 	.kind		= DRV_NAME,
2026 	.priv_size	= sizeof(struct veth_priv),
2027 	.setup		= veth_setup,
2028 	.validate	= veth_validate,
2029 	.newlink	= veth_newlink,
2030 	.dellink	= veth_dellink,
2031 	.policy		= veth_policy,
2032 	.maxtype	= VETH_INFO_MAX,
2033 	.get_link_net	= veth_get_link_net,
2034 	.get_num_tx_queues	= veth_get_num_queues,
2035 	.get_num_rx_queues	= veth_get_num_queues,
2036 };
2037 
2038 /*
2039  * init/fini
2040  */
2041 
2042 static __init int veth_init(void)
2043 {
2044 	return rtnl_link_register(&veth_link_ops);
2045 }
2046 
2047 static __exit void veth_exit(void)
2048 {
2049 	rtnl_link_unregister(&veth_link_ops);
2050 }
2051 
2052 module_init(veth_init);
2053 module_exit(veth_exit);
2054 
2055 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
2056 MODULE_LICENSE("GPL v2");
2057 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
2058