xref: /linux/drivers/net/veth.c (revision 9410645520e9b820069761f3450ef6661418e279)
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 <linux/skbuff_ref.h>
30 #include <net/page_pool/helpers.h>
31 
32 #define DRV_NAME	"veth"
33 #define DRV_VERSION	"1.0"
34 
35 #define VETH_XDP_FLAG		BIT(0)
36 #define VETH_RING_SIZE		256
37 #define VETH_XDP_HEADROOM	(XDP_PACKET_HEADROOM + NET_IP_ALIGN)
38 
39 #define VETH_XDP_TX_BULK_SIZE	16
40 #define VETH_XDP_BATCH		16
41 
42 struct veth_stats {
43 	u64	rx_drops;
44 	/* xdp */
45 	u64	xdp_packets;
46 	u64	xdp_bytes;
47 	u64	xdp_redirect;
48 	u64	xdp_drops;
49 	u64	xdp_tx;
50 	u64	xdp_tx_err;
51 	u64	peer_tq_xdp_xmit;
52 	u64	peer_tq_xdp_xmit_err;
53 };
54 
55 struct veth_rq_stats {
56 	struct veth_stats	vs;
57 	struct u64_stats_sync	syncp;
58 };
59 
60 struct veth_rq {
61 	struct napi_struct	xdp_napi;
62 	struct napi_struct __rcu *napi; /* points to xdp_napi when the latter is initialized */
63 	struct net_device	*dev;
64 	struct bpf_prog __rcu	*xdp_prog;
65 	struct xdp_mem_info	xdp_mem;
66 	struct veth_rq_stats	stats;
67 	bool			rx_notify_masked;
68 	struct ptr_ring		xdp_ring;
69 	struct xdp_rxq_info	xdp_rxq;
70 	struct page_pool	*page_pool;
71 };
72 
73 struct veth_priv {
74 	struct net_device __rcu	*peer;
75 	atomic64_t		dropped;
76 	struct bpf_prog		*_xdp_prog;
77 	struct veth_rq		*rq;
78 	unsigned int		requested_headroom;
79 };
80 
81 struct veth_xdp_tx_bq {
82 	struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
83 	unsigned int count;
84 };
85 
86 /*
87  * ethtool interface
88  */
89 
90 struct veth_q_stat_desc {
91 	char	desc[ETH_GSTRING_LEN];
92 	size_t	offset;
93 };
94 
95 #define VETH_RQ_STAT(m)	offsetof(struct veth_stats, m)
96 
97 static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
98 	{ "xdp_packets",	VETH_RQ_STAT(xdp_packets) },
99 	{ "xdp_bytes",		VETH_RQ_STAT(xdp_bytes) },
100 	{ "drops",		VETH_RQ_STAT(rx_drops) },
101 	{ "xdp_redirect",	VETH_RQ_STAT(xdp_redirect) },
102 	{ "xdp_drops",		VETH_RQ_STAT(xdp_drops) },
103 	{ "xdp_tx",		VETH_RQ_STAT(xdp_tx) },
104 	{ "xdp_tx_errors",	VETH_RQ_STAT(xdp_tx_err) },
105 };
106 
107 #define VETH_RQ_STATS_LEN	ARRAY_SIZE(veth_rq_stats_desc)
108 
109 static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
110 	{ "xdp_xmit",		VETH_RQ_STAT(peer_tq_xdp_xmit) },
111 	{ "xdp_xmit_errors",	VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
112 };
113 
114 #define VETH_TQ_STATS_LEN	ARRAY_SIZE(veth_tq_stats_desc)
115 
116 static struct {
117 	const char string[ETH_GSTRING_LEN];
118 } ethtool_stats_keys[] = {
119 	{ "peer_ifindex" },
120 };
121 
122 struct veth_xdp_buff {
123 	struct xdp_buff xdp;
124 	struct sk_buff *skb;
125 };
126 
veth_get_link_ksettings(struct net_device * dev,struct ethtool_link_ksettings * cmd)127 static int veth_get_link_ksettings(struct net_device *dev,
128 				   struct ethtool_link_ksettings *cmd)
129 {
130 	cmd->base.speed		= SPEED_10000;
131 	cmd->base.duplex	= DUPLEX_FULL;
132 	cmd->base.port		= PORT_TP;
133 	cmd->base.autoneg	= AUTONEG_DISABLE;
134 	return 0;
135 }
136 
veth_get_drvinfo(struct net_device * dev,struct ethtool_drvinfo * info)137 static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
138 {
139 	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
140 	strscpy(info->version, DRV_VERSION, sizeof(info->version));
141 }
142 
veth_get_strings(struct net_device * dev,u32 stringset,u8 * buf)143 static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
144 {
145 	u8 *p = buf;
146 	int i, j;
147 
148 	switch(stringset) {
149 	case ETH_SS_STATS:
150 		memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
151 		p += sizeof(ethtool_stats_keys);
152 		for (i = 0; i < dev->real_num_rx_queues; i++)
153 			for (j = 0; j < VETH_RQ_STATS_LEN; j++)
154 				ethtool_sprintf(&p, "rx_queue_%u_%.18s",
155 						i, veth_rq_stats_desc[j].desc);
156 
157 		for (i = 0; i < dev->real_num_tx_queues; i++)
158 			for (j = 0; j < VETH_TQ_STATS_LEN; j++)
159 				ethtool_sprintf(&p, "tx_queue_%u_%.18s",
160 						i, veth_tq_stats_desc[j].desc);
161 
162 		page_pool_ethtool_stats_get_strings(p);
163 		break;
164 	}
165 }
166 
veth_get_sset_count(struct net_device * dev,int sset)167 static int veth_get_sset_count(struct net_device *dev, int sset)
168 {
169 	switch (sset) {
170 	case ETH_SS_STATS:
171 		return ARRAY_SIZE(ethtool_stats_keys) +
172 		       VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
173 		       VETH_TQ_STATS_LEN * dev->real_num_tx_queues +
174 		       page_pool_ethtool_stats_get_count();
175 	default:
176 		return -EOPNOTSUPP;
177 	}
178 }
179 
veth_get_page_pool_stats(struct net_device * dev,u64 * data)180 static void veth_get_page_pool_stats(struct net_device *dev, u64 *data)
181 {
182 #ifdef CONFIG_PAGE_POOL_STATS
183 	struct veth_priv *priv = netdev_priv(dev);
184 	struct page_pool_stats pp_stats = {};
185 	int i;
186 
187 	for (i = 0; i < dev->real_num_rx_queues; i++) {
188 		if (!priv->rq[i].page_pool)
189 			continue;
190 		page_pool_get_stats(priv->rq[i].page_pool, &pp_stats);
191 	}
192 	page_pool_ethtool_stats_get(data, &pp_stats);
193 #endif /* CONFIG_PAGE_POOL_STATS */
194 }
195 
veth_get_ethtool_stats(struct net_device * dev,struct ethtool_stats * stats,u64 * data)196 static void veth_get_ethtool_stats(struct net_device *dev,
197 		struct ethtool_stats *stats, u64 *data)
198 {
199 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
200 	struct net_device *peer = rtnl_dereference(priv->peer);
201 	int i, j, idx, pp_idx;
202 
203 	data[0] = peer ? peer->ifindex : 0;
204 	idx = 1;
205 	for (i = 0; i < dev->real_num_rx_queues; i++) {
206 		const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
207 		const void *stats_base = (void *)&rq_stats->vs;
208 		unsigned int start;
209 		size_t offset;
210 
211 		do {
212 			start = u64_stats_fetch_begin(&rq_stats->syncp);
213 			for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
214 				offset = veth_rq_stats_desc[j].offset;
215 				data[idx + j] = *(u64 *)(stats_base + offset);
216 			}
217 		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
218 		idx += VETH_RQ_STATS_LEN;
219 	}
220 	pp_idx = idx;
221 
222 	if (!peer)
223 		goto page_pool_stats;
224 
225 	rcv_priv = netdev_priv(peer);
226 	for (i = 0; i < peer->real_num_rx_queues; i++) {
227 		const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
228 		const void *base = (void *)&rq_stats->vs;
229 		unsigned int start, tx_idx = idx;
230 		size_t offset;
231 
232 		tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
233 		do {
234 			start = u64_stats_fetch_begin(&rq_stats->syncp);
235 			for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
236 				offset = veth_tq_stats_desc[j].offset;
237 				data[tx_idx + j] += *(u64 *)(base + offset);
238 			}
239 		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
240 	}
241 	pp_idx = idx + dev->real_num_tx_queues * VETH_TQ_STATS_LEN;
242 
243 page_pool_stats:
244 	veth_get_page_pool_stats(dev, &data[pp_idx]);
245 }
246 
veth_get_channels(struct net_device * dev,struct ethtool_channels * channels)247 static void veth_get_channels(struct net_device *dev,
248 			      struct ethtool_channels *channels)
249 {
250 	channels->tx_count = dev->real_num_tx_queues;
251 	channels->rx_count = dev->real_num_rx_queues;
252 	channels->max_tx = dev->num_tx_queues;
253 	channels->max_rx = dev->num_rx_queues;
254 }
255 
256 static int veth_set_channels(struct net_device *dev,
257 			     struct ethtool_channels *ch);
258 
259 static const struct ethtool_ops veth_ethtool_ops = {
260 	.get_drvinfo		= veth_get_drvinfo,
261 	.get_link		= ethtool_op_get_link,
262 	.get_strings		= veth_get_strings,
263 	.get_sset_count		= veth_get_sset_count,
264 	.get_ethtool_stats	= veth_get_ethtool_stats,
265 	.get_link_ksettings	= veth_get_link_ksettings,
266 	.get_ts_info		= ethtool_op_get_ts_info,
267 	.get_channels		= veth_get_channels,
268 	.set_channels		= veth_set_channels,
269 };
270 
271 /* general routines */
272 
veth_is_xdp_frame(void * ptr)273 static bool veth_is_xdp_frame(void *ptr)
274 {
275 	return (unsigned long)ptr & VETH_XDP_FLAG;
276 }
277 
veth_ptr_to_xdp(void * ptr)278 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
279 {
280 	return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
281 }
282 
veth_xdp_to_ptr(struct xdp_frame * xdp)283 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
284 {
285 	return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
286 }
287 
veth_ptr_free(void * ptr)288 static void veth_ptr_free(void *ptr)
289 {
290 	if (veth_is_xdp_frame(ptr))
291 		xdp_return_frame(veth_ptr_to_xdp(ptr));
292 	else
293 		kfree_skb(ptr);
294 }
295 
__veth_xdp_flush(struct veth_rq * rq)296 static void __veth_xdp_flush(struct veth_rq *rq)
297 {
298 	/* Write ptr_ring before reading rx_notify_masked */
299 	smp_mb();
300 	if (!READ_ONCE(rq->rx_notify_masked) &&
301 	    napi_schedule_prep(&rq->xdp_napi)) {
302 		WRITE_ONCE(rq->rx_notify_masked, true);
303 		__napi_schedule(&rq->xdp_napi);
304 	}
305 }
306 
veth_xdp_rx(struct veth_rq * rq,struct sk_buff * skb)307 static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
308 {
309 	if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
310 		dev_kfree_skb_any(skb);
311 		return NET_RX_DROP;
312 	}
313 
314 	return NET_RX_SUCCESS;
315 }
316 
veth_forward_skb(struct net_device * dev,struct sk_buff * skb,struct veth_rq * rq,bool xdp)317 static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
318 			    struct veth_rq *rq, bool xdp)
319 {
320 	return __dev_forward_skb(dev, skb) ?: xdp ?
321 		veth_xdp_rx(rq, skb) :
322 		__netif_rx(skb);
323 }
324 
325 /* return true if the specified skb has chances of GRO aggregation
326  * Don't strive for accuracy, but try to avoid GRO overhead in the most
327  * common scenarios.
328  * When XDP is enabled, all traffic is considered eligible, as the xmit
329  * device has TSO off.
330  * When TSO is enabled on the xmit device, we are likely interested only
331  * in UDP aggregation, explicitly check for that if the skb is suspected
332  * - the sock_wfree destructor is used by UDP, ICMP and XDP sockets -
333  * to belong to locally generated UDP traffic.
334  */
veth_skb_is_eligible_for_gro(const struct net_device * dev,const struct net_device * rcv,const struct sk_buff * skb)335 static bool veth_skb_is_eligible_for_gro(const struct net_device *dev,
336 					 const struct net_device *rcv,
337 					 const struct sk_buff *skb)
338 {
339 	return !(dev->features & NETIF_F_ALL_TSO) ||
340 		(skb->destructor == sock_wfree &&
341 		 rcv->features & (NETIF_F_GRO_FRAGLIST | NETIF_F_GRO_UDP_FWD));
342 }
343 
veth_xmit(struct sk_buff * skb,struct net_device * dev)344 static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
345 {
346 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
347 	struct veth_rq *rq = NULL;
348 	int ret = NETDEV_TX_OK;
349 	struct net_device *rcv;
350 	int length = skb->len;
351 	bool use_napi = false;
352 	int rxq;
353 
354 	rcu_read_lock();
355 	rcv = rcu_dereference(priv->peer);
356 	if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
357 		kfree_skb(skb);
358 		goto drop;
359 	}
360 
361 	rcv_priv = netdev_priv(rcv);
362 	rxq = skb_get_queue_mapping(skb);
363 	if (rxq < rcv->real_num_rx_queues) {
364 		rq = &rcv_priv->rq[rxq];
365 
366 		/* The napi pointer is available when an XDP program is
367 		 * attached or when GRO is enabled
368 		 * Don't bother with napi/GRO if the skb can't be aggregated
369 		 */
370 		use_napi = rcu_access_pointer(rq->napi) &&
371 			   veth_skb_is_eligible_for_gro(dev, rcv, skb);
372 	}
373 
374 	skb_tx_timestamp(skb);
375 	if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
376 		if (!use_napi)
377 			dev_sw_netstats_tx_add(dev, 1, length);
378 		else
379 			__veth_xdp_flush(rq);
380 	} else {
381 drop:
382 		atomic64_inc(&priv->dropped);
383 		ret = NET_XMIT_DROP;
384 	}
385 
386 	rcu_read_unlock();
387 
388 	return ret;
389 }
390 
veth_stats_rx(struct veth_stats * result,struct net_device * dev)391 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
392 {
393 	struct veth_priv *priv = netdev_priv(dev);
394 	int i;
395 
396 	result->peer_tq_xdp_xmit_err = 0;
397 	result->xdp_packets = 0;
398 	result->xdp_tx_err = 0;
399 	result->xdp_bytes = 0;
400 	result->rx_drops = 0;
401 	for (i = 0; i < dev->num_rx_queues; i++) {
402 		u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
403 		struct veth_rq_stats *stats = &priv->rq[i].stats;
404 		unsigned int start;
405 
406 		do {
407 			start = u64_stats_fetch_begin(&stats->syncp);
408 			peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
409 			xdp_tx_err = stats->vs.xdp_tx_err;
410 			packets = stats->vs.xdp_packets;
411 			bytes = stats->vs.xdp_bytes;
412 			drops = stats->vs.rx_drops;
413 		} while (u64_stats_fetch_retry(&stats->syncp, start));
414 		result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
415 		result->xdp_tx_err += xdp_tx_err;
416 		result->xdp_packets += packets;
417 		result->xdp_bytes += bytes;
418 		result->rx_drops += drops;
419 	}
420 }
421 
veth_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * tot)422 static void veth_get_stats64(struct net_device *dev,
423 			     struct rtnl_link_stats64 *tot)
424 {
425 	struct veth_priv *priv = netdev_priv(dev);
426 	struct net_device *peer;
427 	struct veth_stats rx;
428 
429 	tot->tx_dropped = atomic64_read(&priv->dropped);
430 	dev_fetch_sw_netstats(tot, dev->tstats);
431 
432 	veth_stats_rx(&rx, dev);
433 	tot->tx_dropped += rx.xdp_tx_err;
434 	tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
435 	tot->rx_bytes += rx.xdp_bytes;
436 	tot->rx_packets += rx.xdp_packets;
437 
438 	rcu_read_lock();
439 	peer = rcu_dereference(priv->peer);
440 	if (peer) {
441 		struct rtnl_link_stats64 tot_peer = {};
442 
443 		dev_fetch_sw_netstats(&tot_peer, peer->tstats);
444 		tot->rx_bytes += tot_peer.tx_bytes;
445 		tot->rx_packets += tot_peer.tx_packets;
446 
447 		veth_stats_rx(&rx, peer);
448 		tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
449 		tot->rx_dropped += rx.xdp_tx_err;
450 		tot->tx_bytes += rx.xdp_bytes;
451 		tot->tx_packets += rx.xdp_packets;
452 	}
453 	rcu_read_unlock();
454 }
455 
456 /* fake multicast ability */
veth_set_multicast_list(struct net_device * dev)457 static void veth_set_multicast_list(struct net_device *dev)
458 {
459 }
460 
veth_select_rxq(struct net_device * dev)461 static int veth_select_rxq(struct net_device *dev)
462 {
463 	return smp_processor_id() % dev->real_num_rx_queues;
464 }
465 
veth_peer_dev(struct net_device * dev)466 static struct net_device *veth_peer_dev(struct net_device *dev)
467 {
468 	struct veth_priv *priv = netdev_priv(dev);
469 
470 	/* Callers must be under RCU read side. */
471 	return rcu_dereference(priv->peer);
472 }
473 
veth_xdp_xmit(struct net_device * dev,int n,struct xdp_frame ** frames,u32 flags,bool ndo_xmit)474 static int veth_xdp_xmit(struct net_device *dev, int n,
475 			 struct xdp_frame **frames,
476 			 u32 flags, bool ndo_xmit)
477 {
478 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
479 	int i, ret = -ENXIO, nxmit = 0;
480 	struct net_device *rcv;
481 	unsigned int max_len;
482 	struct veth_rq *rq;
483 
484 	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
485 		return -EINVAL;
486 
487 	rcu_read_lock();
488 	rcv = rcu_dereference(priv->peer);
489 	if (unlikely(!rcv))
490 		goto out;
491 
492 	rcv_priv = netdev_priv(rcv);
493 	rq = &rcv_priv->rq[veth_select_rxq(rcv)];
494 	/* The napi pointer is set if NAPI is enabled, which ensures that
495 	 * xdp_ring is initialized on receive side and the peer device is up.
496 	 */
497 	if (!rcu_access_pointer(rq->napi))
498 		goto out;
499 
500 	max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
501 
502 	spin_lock(&rq->xdp_ring.producer_lock);
503 	for (i = 0; i < n; i++) {
504 		struct xdp_frame *frame = frames[i];
505 		void *ptr = veth_xdp_to_ptr(frame);
506 
507 		if (unlikely(xdp_get_frame_len(frame) > max_len ||
508 			     __ptr_ring_produce(&rq->xdp_ring, ptr)))
509 			break;
510 		nxmit++;
511 	}
512 	spin_unlock(&rq->xdp_ring.producer_lock);
513 
514 	if (flags & XDP_XMIT_FLUSH)
515 		__veth_xdp_flush(rq);
516 
517 	ret = nxmit;
518 	if (ndo_xmit) {
519 		u64_stats_update_begin(&rq->stats.syncp);
520 		rq->stats.vs.peer_tq_xdp_xmit += nxmit;
521 		rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
522 		u64_stats_update_end(&rq->stats.syncp);
523 	}
524 
525 out:
526 	rcu_read_unlock();
527 
528 	return ret;
529 }
530 
veth_ndo_xdp_xmit(struct net_device * dev,int n,struct xdp_frame ** frames,u32 flags)531 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
532 			     struct xdp_frame **frames, u32 flags)
533 {
534 	int err;
535 
536 	err = veth_xdp_xmit(dev, n, frames, flags, true);
537 	if (err < 0) {
538 		struct veth_priv *priv = netdev_priv(dev);
539 
540 		atomic64_add(n, &priv->dropped);
541 	}
542 
543 	return err;
544 }
545 
veth_xdp_flush_bq(struct veth_rq * rq,struct veth_xdp_tx_bq * bq)546 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
547 {
548 	int sent, i, err = 0, drops;
549 
550 	sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
551 	if (sent < 0) {
552 		err = sent;
553 		sent = 0;
554 	}
555 
556 	for (i = sent; unlikely(i < bq->count); i++)
557 		xdp_return_frame(bq->q[i]);
558 
559 	drops = bq->count - sent;
560 	trace_xdp_bulk_tx(rq->dev, sent, drops, err);
561 
562 	u64_stats_update_begin(&rq->stats.syncp);
563 	rq->stats.vs.xdp_tx += sent;
564 	rq->stats.vs.xdp_tx_err += drops;
565 	u64_stats_update_end(&rq->stats.syncp);
566 
567 	bq->count = 0;
568 }
569 
veth_xdp_flush(struct veth_rq * rq,struct veth_xdp_tx_bq * bq)570 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
571 {
572 	struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
573 	struct net_device *rcv;
574 	struct veth_rq *rcv_rq;
575 
576 	rcu_read_lock();
577 	veth_xdp_flush_bq(rq, bq);
578 	rcv = rcu_dereference(priv->peer);
579 	if (unlikely(!rcv))
580 		goto out;
581 
582 	rcv_priv = netdev_priv(rcv);
583 	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
584 	/* xdp_ring is initialized on receive side? */
585 	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
586 		goto out;
587 
588 	__veth_xdp_flush(rcv_rq);
589 out:
590 	rcu_read_unlock();
591 }
592 
veth_xdp_tx(struct veth_rq * rq,struct xdp_buff * xdp,struct veth_xdp_tx_bq * bq)593 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
594 		       struct veth_xdp_tx_bq *bq)
595 {
596 	struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
597 
598 	if (unlikely(!frame))
599 		return -EOVERFLOW;
600 
601 	if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
602 		veth_xdp_flush_bq(rq, bq);
603 
604 	bq->q[bq->count++] = frame;
605 
606 	return 0;
607 }
608 
veth_xdp_rcv_one(struct veth_rq * rq,struct xdp_frame * frame,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)609 static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
610 					  struct xdp_frame *frame,
611 					  struct veth_xdp_tx_bq *bq,
612 					  struct veth_stats *stats)
613 {
614 	struct xdp_frame orig_frame;
615 	struct bpf_prog *xdp_prog;
616 
617 	rcu_read_lock();
618 	xdp_prog = rcu_dereference(rq->xdp_prog);
619 	if (likely(xdp_prog)) {
620 		struct veth_xdp_buff vxbuf;
621 		struct xdp_buff *xdp = &vxbuf.xdp;
622 		u32 act;
623 
624 		xdp_convert_frame_to_buff(frame, xdp);
625 		xdp->rxq = &rq->xdp_rxq;
626 		vxbuf.skb = NULL;
627 
628 		act = bpf_prog_run_xdp(xdp_prog, xdp);
629 
630 		switch (act) {
631 		case XDP_PASS:
632 			if (xdp_update_frame_from_buff(xdp, frame))
633 				goto err_xdp;
634 			break;
635 		case XDP_TX:
636 			orig_frame = *frame;
637 			xdp->rxq->mem = frame->mem;
638 			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
639 				trace_xdp_exception(rq->dev, xdp_prog, act);
640 				frame = &orig_frame;
641 				stats->rx_drops++;
642 				goto err_xdp;
643 			}
644 			stats->xdp_tx++;
645 			rcu_read_unlock();
646 			goto xdp_xmit;
647 		case XDP_REDIRECT:
648 			orig_frame = *frame;
649 			xdp->rxq->mem = frame->mem;
650 			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
651 				frame = &orig_frame;
652 				stats->rx_drops++;
653 				goto err_xdp;
654 			}
655 			stats->xdp_redirect++;
656 			rcu_read_unlock();
657 			goto xdp_xmit;
658 		default:
659 			bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
660 			fallthrough;
661 		case XDP_ABORTED:
662 			trace_xdp_exception(rq->dev, xdp_prog, act);
663 			fallthrough;
664 		case XDP_DROP:
665 			stats->xdp_drops++;
666 			goto err_xdp;
667 		}
668 	}
669 	rcu_read_unlock();
670 
671 	return frame;
672 err_xdp:
673 	rcu_read_unlock();
674 	xdp_return_frame(frame);
675 xdp_xmit:
676 	return NULL;
677 }
678 
679 /* frames array contains VETH_XDP_BATCH at most */
veth_xdp_rcv_bulk_skb(struct veth_rq * rq,void ** frames,int n_xdpf,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)680 static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
681 				  int n_xdpf, struct veth_xdp_tx_bq *bq,
682 				  struct veth_stats *stats)
683 {
684 	void *skbs[VETH_XDP_BATCH];
685 	int i;
686 
687 	if (xdp_alloc_skb_bulk(skbs, n_xdpf,
688 			       GFP_ATOMIC | __GFP_ZERO) < 0) {
689 		for (i = 0; i < n_xdpf; i++)
690 			xdp_return_frame(frames[i]);
691 		stats->rx_drops += n_xdpf;
692 
693 		return;
694 	}
695 
696 	for (i = 0; i < n_xdpf; i++) {
697 		struct sk_buff *skb = skbs[i];
698 
699 		skb = __xdp_build_skb_from_frame(frames[i], skb,
700 						 rq->dev);
701 		if (!skb) {
702 			xdp_return_frame(frames[i]);
703 			stats->rx_drops++;
704 			continue;
705 		}
706 		napi_gro_receive(&rq->xdp_napi, skb);
707 	}
708 }
709 
veth_xdp_get(struct xdp_buff * xdp)710 static void veth_xdp_get(struct xdp_buff *xdp)
711 {
712 	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
713 	int i;
714 
715 	get_page(virt_to_page(xdp->data));
716 	if (likely(!xdp_buff_has_frags(xdp)))
717 		return;
718 
719 	for (i = 0; i < sinfo->nr_frags; i++)
720 		__skb_frag_ref(&sinfo->frags[i]);
721 }
722 
veth_convert_skb_to_xdp_buff(struct veth_rq * rq,struct xdp_buff * xdp,struct sk_buff ** pskb)723 static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
724 					struct xdp_buff *xdp,
725 					struct sk_buff **pskb)
726 {
727 	struct sk_buff *skb = *pskb;
728 	u32 frame_sz;
729 
730 	if (skb_shared(skb) || skb_head_is_locked(skb) ||
731 	    skb_shinfo(skb)->nr_frags ||
732 	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
733 		if (skb_pp_cow_data(rq->page_pool, pskb, XDP_PACKET_HEADROOM))
734 			goto drop;
735 
736 		skb = *pskb;
737 	}
738 
739 	/* SKB "head" area always have tailroom for skb_shared_info */
740 	frame_sz = skb_end_pointer(skb) - skb->head;
741 	frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
742 	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
743 	xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
744 			 skb_headlen(skb), true);
745 
746 	if (skb_is_nonlinear(skb)) {
747 		skb_shinfo(skb)->xdp_frags_size = skb->data_len;
748 		xdp_buff_set_frags_flag(xdp);
749 	} else {
750 		xdp_buff_clear_frags_flag(xdp);
751 	}
752 	*pskb = skb;
753 
754 	return 0;
755 drop:
756 	consume_skb(skb);
757 	*pskb = NULL;
758 
759 	return -ENOMEM;
760 }
761 
veth_xdp_rcv_skb(struct veth_rq * rq,struct sk_buff * skb,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)762 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
763 					struct sk_buff *skb,
764 					struct veth_xdp_tx_bq *bq,
765 					struct veth_stats *stats)
766 {
767 	void *orig_data, *orig_data_end;
768 	struct bpf_prog *xdp_prog;
769 	struct veth_xdp_buff vxbuf;
770 	struct xdp_buff *xdp = &vxbuf.xdp;
771 	u32 act, metalen;
772 	int off;
773 
774 	skb_prepare_for_gro(skb);
775 
776 	rcu_read_lock();
777 	xdp_prog = rcu_dereference(rq->xdp_prog);
778 	if (unlikely(!xdp_prog)) {
779 		rcu_read_unlock();
780 		goto out;
781 	}
782 
783 	__skb_push(skb, skb->data - skb_mac_header(skb));
784 	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
785 		goto drop;
786 	vxbuf.skb = skb;
787 
788 	orig_data = xdp->data;
789 	orig_data_end = xdp->data_end;
790 
791 	act = bpf_prog_run_xdp(xdp_prog, xdp);
792 
793 	switch (act) {
794 	case XDP_PASS:
795 		break;
796 	case XDP_TX:
797 		veth_xdp_get(xdp);
798 		consume_skb(skb);
799 		xdp->rxq->mem = rq->xdp_mem;
800 		if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
801 			trace_xdp_exception(rq->dev, xdp_prog, act);
802 			stats->rx_drops++;
803 			goto err_xdp;
804 		}
805 		stats->xdp_tx++;
806 		rcu_read_unlock();
807 		goto xdp_xmit;
808 	case XDP_REDIRECT:
809 		veth_xdp_get(xdp);
810 		consume_skb(skb);
811 		xdp->rxq->mem = rq->xdp_mem;
812 		if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
813 			stats->rx_drops++;
814 			goto err_xdp;
815 		}
816 		stats->xdp_redirect++;
817 		rcu_read_unlock();
818 		goto xdp_xmit;
819 	default:
820 		bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
821 		fallthrough;
822 	case XDP_ABORTED:
823 		trace_xdp_exception(rq->dev, xdp_prog, act);
824 		fallthrough;
825 	case XDP_DROP:
826 		stats->xdp_drops++;
827 		goto xdp_drop;
828 	}
829 	rcu_read_unlock();
830 
831 	/* check if bpf_xdp_adjust_head was used */
832 	off = orig_data - xdp->data;
833 	if (off > 0)
834 		__skb_push(skb, off);
835 	else if (off < 0)
836 		__skb_pull(skb, -off);
837 
838 	skb_reset_mac_header(skb);
839 
840 	/* check if bpf_xdp_adjust_tail was used */
841 	off = xdp->data_end - orig_data_end;
842 	if (off != 0)
843 		__skb_put(skb, off); /* positive on grow, negative on shrink */
844 
845 	/* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
846 	 * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
847 	 */
848 	if (xdp_buff_has_frags(xdp))
849 		skb->data_len = skb_shinfo(skb)->xdp_frags_size;
850 	else
851 		skb->data_len = 0;
852 
853 	skb->protocol = eth_type_trans(skb, rq->dev);
854 
855 	metalen = xdp->data - xdp->data_meta;
856 	if (metalen)
857 		skb_metadata_set(skb, metalen);
858 out:
859 	return skb;
860 drop:
861 	stats->rx_drops++;
862 xdp_drop:
863 	rcu_read_unlock();
864 	kfree_skb(skb);
865 	return NULL;
866 err_xdp:
867 	rcu_read_unlock();
868 	xdp_return_buff(xdp);
869 xdp_xmit:
870 	return NULL;
871 }
872 
veth_xdp_rcv(struct veth_rq * rq,int budget,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)873 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
874 			struct veth_xdp_tx_bq *bq,
875 			struct veth_stats *stats)
876 {
877 	int i, done = 0, n_xdpf = 0;
878 	void *xdpf[VETH_XDP_BATCH];
879 
880 	for (i = 0; i < budget; i++) {
881 		void *ptr = __ptr_ring_consume(&rq->xdp_ring);
882 
883 		if (!ptr)
884 			break;
885 
886 		if (veth_is_xdp_frame(ptr)) {
887 			/* ndo_xdp_xmit */
888 			struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
889 
890 			stats->xdp_bytes += xdp_get_frame_len(frame);
891 			frame = veth_xdp_rcv_one(rq, frame, bq, stats);
892 			if (frame) {
893 				/* XDP_PASS */
894 				xdpf[n_xdpf++] = frame;
895 				if (n_xdpf == VETH_XDP_BATCH) {
896 					veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
897 							      bq, stats);
898 					n_xdpf = 0;
899 				}
900 			}
901 		} else {
902 			/* ndo_start_xmit */
903 			struct sk_buff *skb = ptr;
904 
905 			stats->xdp_bytes += skb->len;
906 			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
907 			if (skb) {
908 				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
909 					netif_receive_skb(skb);
910 				else
911 					napi_gro_receive(&rq->xdp_napi, skb);
912 			}
913 		}
914 		done++;
915 	}
916 
917 	if (n_xdpf)
918 		veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
919 
920 	u64_stats_update_begin(&rq->stats.syncp);
921 	rq->stats.vs.xdp_redirect += stats->xdp_redirect;
922 	rq->stats.vs.xdp_bytes += stats->xdp_bytes;
923 	rq->stats.vs.xdp_drops += stats->xdp_drops;
924 	rq->stats.vs.rx_drops += stats->rx_drops;
925 	rq->stats.vs.xdp_packets += done;
926 	u64_stats_update_end(&rq->stats.syncp);
927 
928 	return done;
929 }
930 
veth_poll(struct napi_struct * napi,int budget)931 static int veth_poll(struct napi_struct *napi, int budget)
932 {
933 	struct veth_rq *rq =
934 		container_of(napi, struct veth_rq, xdp_napi);
935 	struct veth_stats stats = {};
936 	struct veth_xdp_tx_bq bq;
937 	int done;
938 
939 	bq.count = 0;
940 
941 	xdp_set_return_frame_no_direct();
942 	done = veth_xdp_rcv(rq, budget, &bq, &stats);
943 
944 	if (stats.xdp_redirect > 0)
945 		xdp_do_flush();
946 
947 	if (done < budget && napi_complete_done(napi, done)) {
948 		/* Write rx_notify_masked before reading ptr_ring */
949 		smp_store_mb(rq->rx_notify_masked, false);
950 		if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
951 			if (napi_schedule_prep(&rq->xdp_napi)) {
952 				WRITE_ONCE(rq->rx_notify_masked, true);
953 				__napi_schedule(&rq->xdp_napi);
954 			}
955 		}
956 	}
957 
958 	if (stats.xdp_tx > 0)
959 		veth_xdp_flush(rq, &bq);
960 	xdp_clear_return_frame_no_direct();
961 
962 	return done;
963 }
964 
veth_create_page_pool(struct veth_rq * rq)965 static int veth_create_page_pool(struct veth_rq *rq)
966 {
967 	struct page_pool_params pp_params = {
968 		.order = 0,
969 		.pool_size = VETH_RING_SIZE,
970 		.nid = NUMA_NO_NODE,
971 		.dev = &rq->dev->dev,
972 	};
973 
974 	rq->page_pool = page_pool_create(&pp_params);
975 	if (IS_ERR(rq->page_pool)) {
976 		int err = PTR_ERR(rq->page_pool);
977 
978 		rq->page_pool = NULL;
979 		return err;
980 	}
981 
982 	return 0;
983 }
984 
__veth_napi_enable_range(struct net_device * dev,int start,int end)985 static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
986 {
987 	struct veth_priv *priv = netdev_priv(dev);
988 	int err, i;
989 
990 	for (i = start; i < end; i++) {
991 		err = veth_create_page_pool(&priv->rq[i]);
992 		if (err)
993 			goto err_page_pool;
994 	}
995 
996 	for (i = start; i < end; i++) {
997 		struct veth_rq *rq = &priv->rq[i];
998 
999 		err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
1000 		if (err)
1001 			goto err_xdp_ring;
1002 	}
1003 
1004 	for (i = start; i < end; i++) {
1005 		struct veth_rq *rq = &priv->rq[i];
1006 
1007 		napi_enable(&rq->xdp_napi);
1008 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1009 	}
1010 
1011 	return 0;
1012 
1013 err_xdp_ring:
1014 	for (i--; i >= start; i--)
1015 		ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
1016 	i = end;
1017 err_page_pool:
1018 	for (i--; i >= start; i--) {
1019 		page_pool_destroy(priv->rq[i].page_pool);
1020 		priv->rq[i].page_pool = NULL;
1021 	}
1022 
1023 	return err;
1024 }
1025 
__veth_napi_enable(struct net_device * dev)1026 static int __veth_napi_enable(struct net_device *dev)
1027 {
1028 	return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1029 }
1030 
veth_napi_del_range(struct net_device * dev,int start,int end)1031 static void veth_napi_del_range(struct net_device *dev, int start, int end)
1032 {
1033 	struct veth_priv *priv = netdev_priv(dev);
1034 	int i;
1035 
1036 	for (i = start; i < end; i++) {
1037 		struct veth_rq *rq = &priv->rq[i];
1038 
1039 		rcu_assign_pointer(priv->rq[i].napi, NULL);
1040 		napi_disable(&rq->xdp_napi);
1041 		__netif_napi_del(&rq->xdp_napi);
1042 	}
1043 	synchronize_net();
1044 
1045 	for (i = start; i < end; i++) {
1046 		struct veth_rq *rq = &priv->rq[i];
1047 
1048 		rq->rx_notify_masked = false;
1049 		ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
1050 	}
1051 
1052 	for (i = start; i < end; i++) {
1053 		page_pool_destroy(priv->rq[i].page_pool);
1054 		priv->rq[i].page_pool = NULL;
1055 	}
1056 }
1057 
veth_napi_del(struct net_device * dev)1058 static void veth_napi_del(struct net_device *dev)
1059 {
1060 	veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
1061 }
1062 
veth_gro_requested(const struct net_device * dev)1063 static bool veth_gro_requested(const struct net_device *dev)
1064 {
1065 	return !!(dev->wanted_features & NETIF_F_GRO);
1066 }
1067 
veth_enable_xdp_range(struct net_device * dev,int start,int end,bool napi_already_on)1068 static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
1069 				 bool napi_already_on)
1070 {
1071 	struct veth_priv *priv = netdev_priv(dev);
1072 	int err, i;
1073 
1074 	for (i = start; i < end; i++) {
1075 		struct veth_rq *rq = &priv->rq[i];
1076 
1077 		if (!napi_already_on)
1078 			netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1079 		err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
1080 		if (err < 0)
1081 			goto err_rxq_reg;
1082 
1083 		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
1084 						 MEM_TYPE_PAGE_SHARED,
1085 						 NULL);
1086 		if (err < 0)
1087 			goto err_reg_mem;
1088 
1089 		/* Save original mem info as it can be overwritten */
1090 		rq->xdp_mem = rq->xdp_rxq.mem;
1091 	}
1092 	return 0;
1093 
1094 err_reg_mem:
1095 	xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
1096 err_rxq_reg:
1097 	for (i--; i >= start; i--) {
1098 		struct veth_rq *rq = &priv->rq[i];
1099 
1100 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1101 		if (!napi_already_on)
1102 			netif_napi_del(&rq->xdp_napi);
1103 	}
1104 
1105 	return err;
1106 }
1107 
veth_disable_xdp_range(struct net_device * dev,int start,int end,bool delete_napi)1108 static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
1109 				   bool delete_napi)
1110 {
1111 	struct veth_priv *priv = netdev_priv(dev);
1112 	int i;
1113 
1114 	for (i = start; i < end; i++) {
1115 		struct veth_rq *rq = &priv->rq[i];
1116 
1117 		rq->xdp_rxq.mem = rq->xdp_mem;
1118 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1119 
1120 		if (delete_napi)
1121 			netif_napi_del(&rq->xdp_napi);
1122 	}
1123 }
1124 
veth_enable_xdp(struct net_device * dev)1125 static int veth_enable_xdp(struct net_device *dev)
1126 {
1127 	bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
1128 	struct veth_priv *priv = netdev_priv(dev);
1129 	int err, i;
1130 
1131 	if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
1132 		err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
1133 		if (err)
1134 			return err;
1135 
1136 		if (!napi_already_on) {
1137 			err = __veth_napi_enable(dev);
1138 			if (err) {
1139 				veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
1140 				return err;
1141 			}
1142 		}
1143 	}
1144 
1145 	for (i = 0; i < dev->real_num_rx_queues; i++) {
1146 		rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
1147 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1148 	}
1149 
1150 	return 0;
1151 }
1152 
veth_disable_xdp(struct net_device * dev)1153 static void veth_disable_xdp(struct net_device *dev)
1154 {
1155 	struct veth_priv *priv = netdev_priv(dev);
1156 	int i;
1157 
1158 	for (i = 0; i < dev->real_num_rx_queues; i++)
1159 		rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
1160 
1161 	if (!netif_running(dev) || !veth_gro_requested(dev))
1162 		veth_napi_del(dev);
1163 
1164 	veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
1165 }
1166 
veth_napi_enable_range(struct net_device * dev,int start,int end)1167 static int veth_napi_enable_range(struct net_device *dev, int start, int end)
1168 {
1169 	struct veth_priv *priv = netdev_priv(dev);
1170 	int err, i;
1171 
1172 	for (i = start; i < end; i++) {
1173 		struct veth_rq *rq = &priv->rq[i];
1174 
1175 		netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1176 	}
1177 
1178 	err = __veth_napi_enable_range(dev, start, end);
1179 	if (err) {
1180 		for (i = start; i < end; i++) {
1181 			struct veth_rq *rq = &priv->rq[i];
1182 
1183 			netif_napi_del(&rq->xdp_napi);
1184 		}
1185 		return err;
1186 	}
1187 	return err;
1188 }
1189 
veth_napi_enable(struct net_device * dev)1190 static int veth_napi_enable(struct net_device *dev)
1191 {
1192 	return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1193 }
1194 
veth_disable_range_safe(struct net_device * dev,int start,int end)1195 static void veth_disable_range_safe(struct net_device *dev, int start, int end)
1196 {
1197 	struct veth_priv *priv = netdev_priv(dev);
1198 
1199 	if (start >= end)
1200 		return;
1201 
1202 	if (priv->_xdp_prog) {
1203 		veth_napi_del_range(dev, start, end);
1204 		veth_disable_xdp_range(dev, start, end, false);
1205 	} else if (veth_gro_requested(dev)) {
1206 		veth_napi_del_range(dev, start, end);
1207 	}
1208 }
1209 
veth_enable_range_safe(struct net_device * dev,int start,int end)1210 static int veth_enable_range_safe(struct net_device *dev, int start, int end)
1211 {
1212 	struct veth_priv *priv = netdev_priv(dev);
1213 	int err;
1214 
1215 	if (start >= end)
1216 		return 0;
1217 
1218 	if (priv->_xdp_prog) {
1219 		/* these channels are freshly initialized, napi is not on there even
1220 		 * when GRO is requeste
1221 		 */
1222 		err = veth_enable_xdp_range(dev, start, end, false);
1223 		if (err)
1224 			return err;
1225 
1226 		err = __veth_napi_enable_range(dev, start, end);
1227 		if (err) {
1228 			/* on error always delete the newly added napis */
1229 			veth_disable_xdp_range(dev, start, end, true);
1230 			return err;
1231 		}
1232 	} else if (veth_gro_requested(dev)) {
1233 		return veth_napi_enable_range(dev, start, end);
1234 	}
1235 	return 0;
1236 }
1237 
veth_set_xdp_features(struct net_device * dev)1238 static void veth_set_xdp_features(struct net_device *dev)
1239 {
1240 	struct veth_priv *priv = netdev_priv(dev);
1241 	struct net_device *peer;
1242 
1243 	peer = rtnl_dereference(priv->peer);
1244 	if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
1245 		struct veth_priv *priv_peer = netdev_priv(peer);
1246 		xdp_features_t val = NETDEV_XDP_ACT_BASIC |
1247 				     NETDEV_XDP_ACT_REDIRECT |
1248 				     NETDEV_XDP_ACT_RX_SG;
1249 
1250 		if (priv_peer->_xdp_prog || veth_gro_requested(peer))
1251 			val |= NETDEV_XDP_ACT_NDO_XMIT |
1252 			       NETDEV_XDP_ACT_NDO_XMIT_SG;
1253 		xdp_set_features_flag(dev, val);
1254 	} else {
1255 		xdp_clear_features_flag(dev);
1256 	}
1257 }
1258 
veth_set_channels(struct net_device * dev,struct ethtool_channels * ch)1259 static int veth_set_channels(struct net_device *dev,
1260 			     struct ethtool_channels *ch)
1261 {
1262 	struct veth_priv *priv = netdev_priv(dev);
1263 	unsigned int old_rx_count, new_rx_count;
1264 	struct veth_priv *peer_priv;
1265 	struct net_device *peer;
1266 	int err;
1267 
1268 	/* sanity check. Upper bounds are already enforced by the caller */
1269 	if (!ch->rx_count || !ch->tx_count)
1270 		return -EINVAL;
1271 
1272 	/* avoid braking XDP, if that is enabled */
1273 	peer = rtnl_dereference(priv->peer);
1274 	peer_priv = peer ? netdev_priv(peer) : NULL;
1275 	if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
1276 		return -EINVAL;
1277 
1278 	if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
1279 		return -EINVAL;
1280 
1281 	old_rx_count = dev->real_num_rx_queues;
1282 	new_rx_count = ch->rx_count;
1283 	if (netif_running(dev)) {
1284 		/* turn device off */
1285 		netif_carrier_off(dev);
1286 		if (peer)
1287 			netif_carrier_off(peer);
1288 
1289 		/* try to allocate new resurces, as needed*/
1290 		err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
1291 		if (err)
1292 			goto out;
1293 	}
1294 
1295 	err = netif_set_real_num_rx_queues(dev, ch->rx_count);
1296 	if (err)
1297 		goto revert;
1298 
1299 	err = netif_set_real_num_tx_queues(dev, ch->tx_count);
1300 	if (err) {
1301 		int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
1302 
1303 		/* this error condition could happen only if rx and tx change
1304 		 * in opposite directions (e.g. tx nr raises, rx nr decreases)
1305 		 * and we can't do anything to fully restore the original
1306 		 * status
1307 		 */
1308 		if (err2)
1309 			pr_warn("Can't restore rx queues config %d -> %d %d",
1310 				new_rx_count, old_rx_count, err2);
1311 		else
1312 			goto revert;
1313 	}
1314 
1315 out:
1316 	if (netif_running(dev)) {
1317 		/* note that we need to swap the arguments WRT the enable part
1318 		 * to identify the range we have to disable
1319 		 */
1320 		veth_disable_range_safe(dev, new_rx_count, old_rx_count);
1321 		netif_carrier_on(dev);
1322 		if (peer)
1323 			netif_carrier_on(peer);
1324 	}
1325 
1326 	/* update XDP supported features */
1327 	veth_set_xdp_features(dev);
1328 	if (peer)
1329 		veth_set_xdp_features(peer);
1330 
1331 	return err;
1332 
1333 revert:
1334 	new_rx_count = old_rx_count;
1335 	old_rx_count = ch->rx_count;
1336 	goto out;
1337 }
1338 
veth_open(struct net_device * dev)1339 static int veth_open(struct net_device *dev)
1340 {
1341 	struct veth_priv *priv = netdev_priv(dev);
1342 	struct net_device *peer = rtnl_dereference(priv->peer);
1343 	int err;
1344 
1345 	if (!peer)
1346 		return -ENOTCONN;
1347 
1348 	if (priv->_xdp_prog) {
1349 		err = veth_enable_xdp(dev);
1350 		if (err)
1351 			return err;
1352 	} else if (veth_gro_requested(dev)) {
1353 		err = veth_napi_enable(dev);
1354 		if (err)
1355 			return err;
1356 	}
1357 
1358 	if (peer->flags & IFF_UP) {
1359 		netif_carrier_on(dev);
1360 		netif_carrier_on(peer);
1361 	}
1362 
1363 	veth_set_xdp_features(dev);
1364 
1365 	return 0;
1366 }
1367 
veth_close(struct net_device * dev)1368 static int veth_close(struct net_device *dev)
1369 {
1370 	struct veth_priv *priv = netdev_priv(dev);
1371 	struct net_device *peer = rtnl_dereference(priv->peer);
1372 
1373 	netif_carrier_off(dev);
1374 	if (peer)
1375 		netif_carrier_off(peer);
1376 
1377 	if (priv->_xdp_prog)
1378 		veth_disable_xdp(dev);
1379 	else if (veth_gro_requested(dev))
1380 		veth_napi_del(dev);
1381 
1382 	return 0;
1383 }
1384 
is_valid_veth_mtu(int mtu)1385 static int is_valid_veth_mtu(int mtu)
1386 {
1387 	return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1388 }
1389 
veth_alloc_queues(struct net_device * dev)1390 static int veth_alloc_queues(struct net_device *dev)
1391 {
1392 	struct veth_priv *priv = netdev_priv(dev);
1393 	int i;
1394 
1395 	priv->rq = kvcalloc(dev->num_rx_queues, sizeof(*priv->rq),
1396 			    GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
1397 	if (!priv->rq)
1398 		return -ENOMEM;
1399 
1400 	for (i = 0; i < dev->num_rx_queues; i++) {
1401 		priv->rq[i].dev = dev;
1402 		u64_stats_init(&priv->rq[i].stats.syncp);
1403 	}
1404 
1405 	return 0;
1406 }
1407 
veth_free_queues(struct net_device * dev)1408 static void veth_free_queues(struct net_device *dev)
1409 {
1410 	struct veth_priv *priv = netdev_priv(dev);
1411 
1412 	kvfree(priv->rq);
1413 }
1414 
veth_dev_init(struct net_device * dev)1415 static int veth_dev_init(struct net_device *dev)
1416 {
1417 	netdev_lockdep_set_classes(dev);
1418 	return veth_alloc_queues(dev);
1419 }
1420 
veth_dev_free(struct net_device * dev)1421 static void veth_dev_free(struct net_device *dev)
1422 {
1423 	veth_free_queues(dev);
1424 }
1425 
1426 #ifdef CONFIG_NET_POLL_CONTROLLER
veth_poll_controller(struct net_device * dev)1427 static void veth_poll_controller(struct net_device *dev)
1428 {
1429 	/* veth only receives frames when its peer sends one
1430 	 * Since it has nothing to do with disabling irqs, we are guaranteed
1431 	 * never to have pending data when we poll for it so
1432 	 * there is nothing to do here.
1433 	 *
1434 	 * We need this though so netpoll recognizes us as an interface that
1435 	 * supports polling, which enables bridge devices in virt setups to
1436 	 * still use netconsole
1437 	 */
1438 }
1439 #endif	/* CONFIG_NET_POLL_CONTROLLER */
1440 
veth_get_iflink(const struct net_device * dev)1441 static int veth_get_iflink(const struct net_device *dev)
1442 {
1443 	struct veth_priv *priv = netdev_priv(dev);
1444 	struct net_device *peer;
1445 	int iflink;
1446 
1447 	rcu_read_lock();
1448 	peer = rcu_dereference(priv->peer);
1449 	iflink = peer ? READ_ONCE(peer->ifindex) : 0;
1450 	rcu_read_unlock();
1451 
1452 	return iflink;
1453 }
1454 
veth_fix_features(struct net_device * dev,netdev_features_t features)1455 static netdev_features_t veth_fix_features(struct net_device *dev,
1456 					   netdev_features_t features)
1457 {
1458 	struct veth_priv *priv = netdev_priv(dev);
1459 	struct net_device *peer;
1460 
1461 	peer = rtnl_dereference(priv->peer);
1462 	if (peer) {
1463 		struct veth_priv *peer_priv = netdev_priv(peer);
1464 
1465 		if (peer_priv->_xdp_prog)
1466 			features &= ~NETIF_F_GSO_SOFTWARE;
1467 	}
1468 
1469 	return features;
1470 }
1471 
veth_set_features(struct net_device * dev,netdev_features_t features)1472 static int veth_set_features(struct net_device *dev,
1473 			     netdev_features_t features)
1474 {
1475 	netdev_features_t changed = features ^ dev->features;
1476 	struct veth_priv *priv = netdev_priv(dev);
1477 	struct net_device *peer;
1478 	int err;
1479 
1480 	if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
1481 		return 0;
1482 
1483 	peer = rtnl_dereference(priv->peer);
1484 	if (features & NETIF_F_GRO) {
1485 		err = veth_napi_enable(dev);
1486 		if (err)
1487 			return err;
1488 
1489 		if (peer)
1490 			xdp_features_set_redirect_target(peer, true);
1491 	} else {
1492 		if (peer)
1493 			xdp_features_clear_redirect_target(peer);
1494 		veth_napi_del(dev);
1495 	}
1496 	return 0;
1497 }
1498 
veth_set_rx_headroom(struct net_device * dev,int new_hr)1499 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1500 {
1501 	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1502 	struct net_device *peer;
1503 
1504 	if (new_hr < 0)
1505 		new_hr = 0;
1506 
1507 	rcu_read_lock();
1508 	peer = rcu_dereference(priv->peer);
1509 	if (unlikely(!peer))
1510 		goto out;
1511 
1512 	peer_priv = netdev_priv(peer);
1513 	priv->requested_headroom = new_hr;
1514 	new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1515 	dev->needed_headroom = new_hr;
1516 	peer->needed_headroom = new_hr;
1517 
1518 out:
1519 	rcu_read_unlock();
1520 }
1521 
veth_xdp_set(struct net_device * dev,struct bpf_prog * prog,struct netlink_ext_ack * extack)1522 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1523 			struct netlink_ext_ack *extack)
1524 {
1525 	struct veth_priv *priv = netdev_priv(dev);
1526 	struct bpf_prog *old_prog;
1527 	struct net_device *peer;
1528 	unsigned int max_mtu;
1529 	int err;
1530 
1531 	old_prog = priv->_xdp_prog;
1532 	priv->_xdp_prog = prog;
1533 	peer = rtnl_dereference(priv->peer);
1534 
1535 	if (prog) {
1536 		if (!peer) {
1537 			NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1538 			err = -ENOTCONN;
1539 			goto err;
1540 		}
1541 
1542 		max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
1543 			  peer->hard_header_len;
1544 		/* Allow increasing the max_mtu if the program supports
1545 		 * XDP fragments.
1546 		 */
1547 		if (prog->aux->xdp_has_frags)
1548 			max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
1549 
1550 		if (peer->mtu > max_mtu) {
1551 			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1552 			err = -ERANGE;
1553 			goto err;
1554 		}
1555 
1556 		if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1557 			NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1558 			err = -ENOSPC;
1559 			goto err;
1560 		}
1561 
1562 		if (dev->flags & IFF_UP) {
1563 			err = veth_enable_xdp(dev);
1564 			if (err) {
1565 				NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1566 				goto err;
1567 			}
1568 		}
1569 
1570 		if (!old_prog) {
1571 			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1572 			peer->max_mtu = max_mtu;
1573 		}
1574 
1575 		xdp_features_set_redirect_target(peer, true);
1576 	}
1577 
1578 	if (old_prog) {
1579 		if (!prog) {
1580 			if (peer && !veth_gro_requested(dev))
1581 				xdp_features_clear_redirect_target(peer);
1582 
1583 			if (dev->flags & IFF_UP)
1584 				veth_disable_xdp(dev);
1585 
1586 			if (peer) {
1587 				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1588 				peer->max_mtu = ETH_MAX_MTU;
1589 			}
1590 		}
1591 		bpf_prog_put(old_prog);
1592 	}
1593 
1594 	if ((!!old_prog ^ !!prog) && peer)
1595 		netdev_update_features(peer);
1596 
1597 	return 0;
1598 err:
1599 	priv->_xdp_prog = old_prog;
1600 
1601 	return err;
1602 }
1603 
veth_xdp(struct net_device * dev,struct netdev_bpf * xdp)1604 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1605 {
1606 	switch (xdp->command) {
1607 	case XDP_SETUP_PROG:
1608 		return veth_xdp_set(dev, xdp->prog, xdp->extack);
1609 	default:
1610 		return -EINVAL;
1611 	}
1612 }
1613 
veth_xdp_rx_timestamp(const struct xdp_md * ctx,u64 * timestamp)1614 static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
1615 {
1616 	struct veth_xdp_buff *_ctx = (void *)ctx;
1617 
1618 	if (!_ctx->skb)
1619 		return -ENODATA;
1620 
1621 	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
1622 	return 0;
1623 }
1624 
veth_xdp_rx_hash(const struct xdp_md * ctx,u32 * hash,enum xdp_rss_hash_type * rss_type)1625 static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
1626 			    enum xdp_rss_hash_type *rss_type)
1627 {
1628 	struct veth_xdp_buff *_ctx = (void *)ctx;
1629 	struct sk_buff *skb = _ctx->skb;
1630 
1631 	if (!skb)
1632 		return -ENODATA;
1633 
1634 	*hash = skb_get_hash(skb);
1635 	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;
1636 
1637 	return 0;
1638 }
1639 
veth_xdp_rx_vlan_tag(const struct xdp_md * ctx,__be16 * vlan_proto,u16 * vlan_tci)1640 static int veth_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
1641 				u16 *vlan_tci)
1642 {
1643 	const struct veth_xdp_buff *_ctx = (void *)ctx;
1644 	const struct sk_buff *skb = _ctx->skb;
1645 	int err;
1646 
1647 	if (!skb)
1648 		return -ENODATA;
1649 
1650 	err = __vlan_hwaccel_get_tag(skb, vlan_tci);
1651 	if (err)
1652 		return err;
1653 
1654 	*vlan_proto = skb->vlan_proto;
1655 	return err;
1656 }
1657 
1658 static const struct net_device_ops veth_netdev_ops = {
1659 	.ndo_init            = veth_dev_init,
1660 	.ndo_open            = veth_open,
1661 	.ndo_stop            = veth_close,
1662 	.ndo_start_xmit      = veth_xmit,
1663 	.ndo_get_stats64     = veth_get_stats64,
1664 	.ndo_set_rx_mode     = veth_set_multicast_list,
1665 	.ndo_set_mac_address = eth_mac_addr,
1666 #ifdef CONFIG_NET_POLL_CONTROLLER
1667 	.ndo_poll_controller	= veth_poll_controller,
1668 #endif
1669 	.ndo_get_iflink		= veth_get_iflink,
1670 	.ndo_fix_features	= veth_fix_features,
1671 	.ndo_set_features	= veth_set_features,
1672 	.ndo_features_check	= passthru_features_check,
1673 	.ndo_set_rx_headroom	= veth_set_rx_headroom,
1674 	.ndo_bpf		= veth_xdp,
1675 	.ndo_xdp_xmit		= veth_ndo_xdp_xmit,
1676 	.ndo_get_peer_dev	= veth_peer_dev,
1677 };
1678 
1679 static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
1680 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
1681 	.xmo_rx_hash			= veth_xdp_rx_hash,
1682 	.xmo_rx_vlan_tag		= veth_xdp_rx_vlan_tag,
1683 };
1684 
1685 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1686 		       NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1687 		       NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1688 		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1689 		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1690 
veth_setup(struct net_device * dev)1691 static void veth_setup(struct net_device *dev)
1692 {
1693 	ether_setup(dev);
1694 
1695 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1696 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1697 	dev->priv_flags |= IFF_NO_QUEUE;
1698 	dev->priv_flags |= IFF_PHONY_HEADROOM;
1699 	dev->priv_flags |= IFF_DISABLE_NETPOLL;
1700 	dev->lltx = true;
1701 
1702 	dev->netdev_ops = &veth_netdev_ops;
1703 	dev->xdp_metadata_ops = &veth_xdp_metadata_ops;
1704 	dev->ethtool_ops = &veth_ethtool_ops;
1705 	dev->features |= VETH_FEATURES;
1706 	dev->vlan_features = dev->features &
1707 			     ~(NETIF_F_HW_VLAN_CTAG_TX |
1708 			       NETIF_F_HW_VLAN_STAG_TX |
1709 			       NETIF_F_HW_VLAN_CTAG_RX |
1710 			       NETIF_F_HW_VLAN_STAG_RX);
1711 	dev->needs_free_netdev = true;
1712 	dev->priv_destructor = veth_dev_free;
1713 	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1714 	dev->max_mtu = ETH_MAX_MTU;
1715 
1716 	dev->hw_features = VETH_FEATURES;
1717 	dev->hw_enc_features = VETH_FEATURES;
1718 	dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1719 	netif_set_tso_max_size(dev, GSO_MAX_SIZE);
1720 }
1721 
1722 /*
1723  * netlink interface
1724  */
1725 
veth_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1726 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1727 			 struct netlink_ext_ack *extack)
1728 {
1729 	if (tb[IFLA_ADDRESS]) {
1730 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1731 			return -EINVAL;
1732 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1733 			return -EADDRNOTAVAIL;
1734 	}
1735 	if (tb[IFLA_MTU]) {
1736 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1737 			return -EINVAL;
1738 	}
1739 	return 0;
1740 }
1741 
1742 static struct rtnl_link_ops veth_link_ops;
1743 
veth_disable_gro(struct net_device * dev)1744 static void veth_disable_gro(struct net_device *dev)
1745 {
1746 	dev->features &= ~NETIF_F_GRO;
1747 	dev->wanted_features &= ~NETIF_F_GRO;
1748 	netdev_update_features(dev);
1749 }
1750 
veth_init_queues(struct net_device * dev,struct nlattr * tb[])1751 static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
1752 {
1753 	int err;
1754 
1755 	if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
1756 		err = netif_set_real_num_tx_queues(dev, 1);
1757 		if (err)
1758 			return err;
1759 	}
1760 	if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
1761 		err = netif_set_real_num_rx_queues(dev, 1);
1762 		if (err)
1763 			return err;
1764 	}
1765 	return 0;
1766 }
1767 
veth_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1768 static int veth_newlink(struct net *src_net, struct net_device *dev,
1769 			struct nlattr *tb[], struct nlattr *data[],
1770 			struct netlink_ext_ack *extack)
1771 {
1772 	int err;
1773 	struct net_device *peer;
1774 	struct veth_priv *priv;
1775 	char ifname[IFNAMSIZ];
1776 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1777 	unsigned char name_assign_type;
1778 	struct ifinfomsg *ifmp;
1779 	struct net *net;
1780 
1781 	/*
1782 	 * create and register peer first
1783 	 */
1784 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1785 		struct nlattr *nla_peer;
1786 
1787 		nla_peer = data[VETH_INFO_PEER];
1788 		ifmp = nla_data(nla_peer);
1789 		err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack);
1790 		if (err < 0)
1791 			return err;
1792 
1793 		err = veth_validate(peer_tb, NULL, extack);
1794 		if (err < 0)
1795 			return err;
1796 
1797 		tbp = peer_tb;
1798 	} else {
1799 		ifmp = NULL;
1800 		tbp = tb;
1801 	}
1802 
1803 	if (ifmp && tbp[IFLA_IFNAME]) {
1804 		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1805 		name_assign_type = NET_NAME_USER;
1806 	} else {
1807 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1808 		name_assign_type = NET_NAME_ENUM;
1809 	}
1810 
1811 	net = rtnl_link_get_net(src_net, tbp);
1812 	if (IS_ERR(net))
1813 		return PTR_ERR(net);
1814 
1815 	peer = rtnl_create_link(net, ifname, name_assign_type,
1816 				&veth_link_ops, tbp, extack);
1817 	if (IS_ERR(peer)) {
1818 		put_net(net);
1819 		return PTR_ERR(peer);
1820 	}
1821 
1822 	if (!ifmp || !tbp[IFLA_ADDRESS])
1823 		eth_hw_addr_random(peer);
1824 
1825 	if (ifmp && (dev->ifindex != 0))
1826 		peer->ifindex = ifmp->ifi_index;
1827 
1828 	netif_inherit_tso_max(peer, dev);
1829 
1830 	err = register_netdevice(peer);
1831 	put_net(net);
1832 	net = NULL;
1833 	if (err < 0)
1834 		goto err_register_peer;
1835 
1836 	/* keep GRO disabled by default to be consistent with the established
1837 	 * veth behavior
1838 	 */
1839 	veth_disable_gro(peer);
1840 	netif_carrier_off(peer);
1841 
1842 	err = rtnl_configure_link(peer, ifmp, 0, NULL);
1843 	if (err < 0)
1844 		goto err_configure_peer;
1845 
1846 	/*
1847 	 * register dev last
1848 	 *
1849 	 * note, that since we've registered new device the dev's name
1850 	 * should be re-allocated
1851 	 */
1852 
1853 	if (tb[IFLA_ADDRESS] == NULL)
1854 		eth_hw_addr_random(dev);
1855 
1856 	if (tb[IFLA_IFNAME])
1857 		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1858 	else
1859 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1860 
1861 	err = register_netdevice(dev);
1862 	if (err < 0)
1863 		goto err_register_dev;
1864 
1865 	netif_carrier_off(dev);
1866 
1867 	/*
1868 	 * tie the deviced together
1869 	 */
1870 
1871 	priv = netdev_priv(dev);
1872 	rcu_assign_pointer(priv->peer, peer);
1873 	err = veth_init_queues(dev, tb);
1874 	if (err)
1875 		goto err_queues;
1876 
1877 	priv = netdev_priv(peer);
1878 	rcu_assign_pointer(priv->peer, dev);
1879 	err = veth_init_queues(peer, tb);
1880 	if (err)
1881 		goto err_queues;
1882 
1883 	veth_disable_gro(dev);
1884 	/* update XDP supported features */
1885 	veth_set_xdp_features(dev);
1886 	veth_set_xdp_features(peer);
1887 
1888 	return 0;
1889 
1890 err_queues:
1891 	unregister_netdevice(dev);
1892 err_register_dev:
1893 	/* nothing to do */
1894 err_configure_peer:
1895 	unregister_netdevice(peer);
1896 	return err;
1897 
1898 err_register_peer:
1899 	free_netdev(peer);
1900 	return err;
1901 }
1902 
veth_dellink(struct net_device * dev,struct list_head * head)1903 static void veth_dellink(struct net_device *dev, struct list_head *head)
1904 {
1905 	struct veth_priv *priv;
1906 	struct net_device *peer;
1907 
1908 	priv = netdev_priv(dev);
1909 	peer = rtnl_dereference(priv->peer);
1910 
1911 	/* Note : dellink() is called from default_device_exit_batch(),
1912 	 * before a rcu_synchronize() point. The devices are guaranteed
1913 	 * not being freed before one RCU grace period.
1914 	 */
1915 	RCU_INIT_POINTER(priv->peer, NULL);
1916 	unregister_netdevice_queue(dev, head);
1917 
1918 	if (peer) {
1919 		priv = netdev_priv(peer);
1920 		RCU_INIT_POINTER(priv->peer, NULL);
1921 		unregister_netdevice_queue(peer, head);
1922 	}
1923 }
1924 
1925 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1926 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
1927 };
1928 
veth_get_link_net(const struct net_device * dev)1929 static struct net *veth_get_link_net(const struct net_device *dev)
1930 {
1931 	struct veth_priv *priv = netdev_priv(dev);
1932 	struct net_device *peer = rtnl_dereference(priv->peer);
1933 
1934 	return peer ? dev_net(peer) : dev_net(dev);
1935 }
1936 
veth_get_num_queues(void)1937 static unsigned int veth_get_num_queues(void)
1938 {
1939 	/* enforce the same queue limit as rtnl_create_link */
1940 	int queues = num_possible_cpus();
1941 
1942 	if (queues > 4096)
1943 		queues = 4096;
1944 	return queues;
1945 }
1946 
1947 static struct rtnl_link_ops veth_link_ops = {
1948 	.kind		= DRV_NAME,
1949 	.priv_size	= sizeof(struct veth_priv),
1950 	.setup		= veth_setup,
1951 	.validate	= veth_validate,
1952 	.newlink	= veth_newlink,
1953 	.dellink	= veth_dellink,
1954 	.policy		= veth_policy,
1955 	.maxtype	= VETH_INFO_MAX,
1956 	.get_link_net	= veth_get_link_net,
1957 	.get_num_tx_queues	= veth_get_num_queues,
1958 	.get_num_rx_queues	= veth_get_num_queues,
1959 };
1960 
1961 /*
1962  * init/fini
1963  */
1964 
veth_init(void)1965 static __init int veth_init(void)
1966 {
1967 	return rtnl_link_register(&veth_link_ops);
1968 }
1969 
veth_exit(void)1970 static __exit void veth_exit(void)
1971 {
1972 	rtnl_link_unregister(&veth_link_ops);
1973 }
1974 
1975 module_init(veth_init);
1976 module_exit(veth_exit);
1977 
1978 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
1979 MODULE_LICENSE("GPL v2");
1980 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
1981