xref: /openbmc/linux/drivers/net/veth.c (revision a7b862ab)
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 
veth_get_link_ksettings(struct net_device * dev,struct ethtool_link_ksettings * cmd)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 
veth_get_drvinfo(struct net_device * dev,struct ethtool_drvinfo * info)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 
veth_get_strings(struct net_device * dev,u32 stringset,u8 * buf)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 
veth_get_sset_count(struct net_device * dev,int sset)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 
veth_get_page_pool_stats(struct net_device * dev,u64 * data)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 
veth_get_ethtool_stats(struct net_device * dev,struct ethtool_stats * stats,u64 * data)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 	}
240 	pp_idx = idx + dev->real_num_tx_queues * VETH_TQ_STATS_LEN;
241 
242 page_pool_stats:
243 	veth_get_page_pool_stats(dev, &data[pp_idx]);
244 }
245 
veth_get_channels(struct net_device * dev,struct ethtool_channels * channels)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 
veth_is_xdp_frame(void * ptr)272 static bool veth_is_xdp_frame(void *ptr)
273 {
274 	return (unsigned long)ptr & VETH_XDP_FLAG;
275 }
276 
veth_ptr_to_xdp(void * ptr)277 static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
278 {
279 	return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
280 }
281 
veth_xdp_to_ptr(struct xdp_frame * xdp)282 static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
283 {
284 	return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
285 }
286 
veth_ptr_free(void * ptr)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 
__veth_xdp_flush(struct veth_rq * rq)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 
veth_xdp_rx(struct veth_rq * rq,struct sk_buff * skb)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 
veth_forward_skb(struct net_device * dev,struct sk_buff * skb,struct veth_rq * rq,bool xdp)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  */
veth_skb_is_eligible_for_gro(const struct net_device * dev,const struct net_device * rcv,const struct sk_buff * skb)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 
veth_xmit(struct sk_buff * skb,struct net_device * dev)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 	int ret = NETDEV_TX_OK;
348 	struct net_device *rcv;
349 	int length = skb->len;
350 	bool use_napi = false;
351 	int rxq;
352 
353 	rcu_read_lock();
354 	rcv = rcu_dereference(priv->peer);
355 	if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
356 		kfree_skb(skb);
357 		goto drop;
358 	}
359 
360 	rcv_priv = netdev_priv(rcv);
361 	rxq = skb_get_queue_mapping(skb);
362 	if (rxq < rcv->real_num_rx_queues) {
363 		rq = &rcv_priv->rq[rxq];
364 
365 		/* The napi pointer is available when an XDP program is
366 		 * attached or when GRO is enabled
367 		 * Don't bother with napi/GRO if the skb can't be aggregated
368 		 */
369 		use_napi = rcu_access_pointer(rq->napi) &&
370 			   veth_skb_is_eligible_for_gro(dev, rcv, skb);
371 	}
372 
373 	skb_tx_timestamp(skb);
374 	if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
375 		if (!use_napi)
376 			dev_sw_netstats_tx_add(dev, 1, length);
377 		else
378 			__veth_xdp_flush(rq);
379 	} else {
380 drop:
381 		atomic64_inc(&priv->dropped);
382 		ret = NET_XMIT_DROP;
383 	}
384 
385 	rcu_read_unlock();
386 
387 	return ret;
388 }
389 
veth_stats_rx(struct veth_stats * result,struct net_device * dev)390 static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
391 {
392 	struct veth_priv *priv = netdev_priv(dev);
393 	int i;
394 
395 	result->peer_tq_xdp_xmit_err = 0;
396 	result->xdp_packets = 0;
397 	result->xdp_tx_err = 0;
398 	result->xdp_bytes = 0;
399 	result->rx_drops = 0;
400 	for (i = 0; i < dev->num_rx_queues; i++) {
401 		u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
402 		struct veth_rq_stats *stats = &priv->rq[i].stats;
403 		unsigned int start;
404 
405 		do {
406 			start = u64_stats_fetch_begin(&stats->syncp);
407 			peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
408 			xdp_tx_err = stats->vs.xdp_tx_err;
409 			packets = stats->vs.xdp_packets;
410 			bytes = stats->vs.xdp_bytes;
411 			drops = stats->vs.rx_drops;
412 		} while (u64_stats_fetch_retry(&stats->syncp, start));
413 		result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
414 		result->xdp_tx_err += xdp_tx_err;
415 		result->xdp_packets += packets;
416 		result->xdp_bytes += bytes;
417 		result->rx_drops += drops;
418 	}
419 }
420 
veth_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * tot)421 static void veth_get_stats64(struct net_device *dev,
422 			     struct rtnl_link_stats64 *tot)
423 {
424 	struct veth_priv *priv = netdev_priv(dev);
425 	struct net_device *peer;
426 	struct veth_stats rx;
427 
428 	tot->tx_dropped = atomic64_read(&priv->dropped);
429 	dev_fetch_sw_netstats(tot, dev->tstats);
430 
431 	veth_stats_rx(&rx, dev);
432 	tot->tx_dropped += rx.xdp_tx_err;
433 	tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
434 	tot->rx_bytes += rx.xdp_bytes;
435 	tot->rx_packets += rx.xdp_packets;
436 
437 	rcu_read_lock();
438 	peer = rcu_dereference(priv->peer);
439 	if (peer) {
440 		struct rtnl_link_stats64 tot_peer = {};
441 
442 		dev_fetch_sw_netstats(&tot_peer, peer->tstats);
443 		tot->rx_bytes += tot_peer.tx_bytes;
444 		tot->rx_packets += tot_peer.tx_packets;
445 
446 		veth_stats_rx(&rx, peer);
447 		tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
448 		tot->rx_dropped += rx.xdp_tx_err;
449 		tot->tx_bytes += rx.xdp_bytes;
450 		tot->tx_packets += rx.xdp_packets;
451 	}
452 	rcu_read_unlock();
453 }
454 
455 /* fake multicast ability */
veth_set_multicast_list(struct net_device * dev)456 static void veth_set_multicast_list(struct net_device *dev)
457 {
458 }
459 
veth_select_rxq(struct net_device * dev)460 static int veth_select_rxq(struct net_device *dev)
461 {
462 	return smp_processor_id() % dev->real_num_rx_queues;
463 }
464 
veth_peer_dev(struct net_device * dev)465 static struct net_device *veth_peer_dev(struct net_device *dev)
466 {
467 	struct veth_priv *priv = netdev_priv(dev);
468 
469 	/* Callers must be under RCU read side. */
470 	return rcu_dereference(priv->peer);
471 }
472 
veth_xdp_xmit(struct net_device * dev,int n,struct xdp_frame ** frames,u32 flags,bool ndo_xmit)473 static int veth_xdp_xmit(struct net_device *dev, int n,
474 			 struct xdp_frame **frames,
475 			 u32 flags, bool ndo_xmit)
476 {
477 	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
478 	int i, ret = -ENXIO, nxmit = 0;
479 	struct net_device *rcv;
480 	unsigned int max_len;
481 	struct veth_rq *rq;
482 
483 	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
484 		return -EINVAL;
485 
486 	rcu_read_lock();
487 	rcv = rcu_dereference(priv->peer);
488 	if (unlikely(!rcv))
489 		goto out;
490 
491 	rcv_priv = netdev_priv(rcv);
492 	rq = &rcv_priv->rq[veth_select_rxq(rcv)];
493 	/* The napi pointer is set if NAPI is enabled, which ensures that
494 	 * xdp_ring is initialized on receive side and the peer device is up.
495 	 */
496 	if (!rcu_access_pointer(rq->napi))
497 		goto out;
498 
499 	max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;
500 
501 	spin_lock(&rq->xdp_ring.producer_lock);
502 	for (i = 0; i < n; i++) {
503 		struct xdp_frame *frame = frames[i];
504 		void *ptr = veth_xdp_to_ptr(frame);
505 
506 		if (unlikely(xdp_get_frame_len(frame) > max_len ||
507 			     __ptr_ring_produce(&rq->xdp_ring, ptr)))
508 			break;
509 		nxmit++;
510 	}
511 	spin_unlock(&rq->xdp_ring.producer_lock);
512 
513 	if (flags & XDP_XMIT_FLUSH)
514 		__veth_xdp_flush(rq);
515 
516 	ret = nxmit;
517 	if (ndo_xmit) {
518 		u64_stats_update_begin(&rq->stats.syncp);
519 		rq->stats.vs.peer_tq_xdp_xmit += nxmit;
520 		rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
521 		u64_stats_update_end(&rq->stats.syncp);
522 	}
523 
524 out:
525 	rcu_read_unlock();
526 
527 	return ret;
528 }
529 
veth_ndo_xdp_xmit(struct net_device * dev,int n,struct xdp_frame ** frames,u32 flags)530 static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
531 			     struct xdp_frame **frames, u32 flags)
532 {
533 	int err;
534 
535 	err = veth_xdp_xmit(dev, n, frames, flags, true);
536 	if (err < 0) {
537 		struct veth_priv *priv = netdev_priv(dev);
538 
539 		atomic64_add(n, &priv->dropped);
540 	}
541 
542 	return err;
543 }
544 
veth_xdp_flush_bq(struct veth_rq * rq,struct veth_xdp_tx_bq * bq)545 static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
546 {
547 	int sent, i, err = 0, drops;
548 
549 	sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
550 	if (sent < 0) {
551 		err = sent;
552 		sent = 0;
553 	}
554 
555 	for (i = sent; unlikely(i < bq->count); i++)
556 		xdp_return_frame(bq->q[i]);
557 
558 	drops = bq->count - sent;
559 	trace_xdp_bulk_tx(rq->dev, sent, drops, err);
560 
561 	u64_stats_update_begin(&rq->stats.syncp);
562 	rq->stats.vs.xdp_tx += sent;
563 	rq->stats.vs.xdp_tx_err += drops;
564 	u64_stats_update_end(&rq->stats.syncp);
565 
566 	bq->count = 0;
567 }
568 
veth_xdp_flush(struct veth_rq * rq,struct veth_xdp_tx_bq * bq)569 static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
570 {
571 	struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
572 	struct net_device *rcv;
573 	struct veth_rq *rcv_rq;
574 
575 	rcu_read_lock();
576 	veth_xdp_flush_bq(rq, bq);
577 	rcv = rcu_dereference(priv->peer);
578 	if (unlikely(!rcv))
579 		goto out;
580 
581 	rcv_priv = netdev_priv(rcv);
582 	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
583 	/* xdp_ring is initialized on receive side? */
584 	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
585 		goto out;
586 
587 	__veth_xdp_flush(rcv_rq);
588 out:
589 	rcu_read_unlock();
590 }
591 
veth_xdp_tx(struct veth_rq * rq,struct xdp_buff * xdp,struct veth_xdp_tx_bq * bq)592 static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
593 		       struct veth_xdp_tx_bq *bq)
594 {
595 	struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);
596 
597 	if (unlikely(!frame))
598 		return -EOVERFLOW;
599 
600 	if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
601 		veth_xdp_flush_bq(rq, bq);
602 
603 	bq->q[bq->count++] = frame;
604 
605 	return 0;
606 }
607 
veth_xdp_rcv_one(struct veth_rq * rq,struct xdp_frame * frame,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)608 static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
609 					  struct xdp_frame *frame,
610 					  struct veth_xdp_tx_bq *bq,
611 					  struct veth_stats *stats)
612 {
613 	struct xdp_frame orig_frame;
614 	struct bpf_prog *xdp_prog;
615 
616 	rcu_read_lock();
617 	xdp_prog = rcu_dereference(rq->xdp_prog);
618 	if (likely(xdp_prog)) {
619 		struct veth_xdp_buff vxbuf;
620 		struct xdp_buff *xdp = &vxbuf.xdp;
621 		u32 act;
622 
623 		xdp_convert_frame_to_buff(frame, xdp);
624 		xdp->rxq = &rq->xdp_rxq;
625 		vxbuf.skb = NULL;
626 
627 		act = bpf_prog_run_xdp(xdp_prog, xdp);
628 
629 		switch (act) {
630 		case XDP_PASS:
631 			if (xdp_update_frame_from_buff(xdp, frame))
632 				goto err_xdp;
633 			break;
634 		case XDP_TX:
635 			orig_frame = *frame;
636 			xdp->rxq->mem = frame->mem;
637 			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
638 				trace_xdp_exception(rq->dev, xdp_prog, act);
639 				frame = &orig_frame;
640 				stats->rx_drops++;
641 				goto err_xdp;
642 			}
643 			stats->xdp_tx++;
644 			rcu_read_unlock();
645 			goto xdp_xmit;
646 		case XDP_REDIRECT:
647 			orig_frame = *frame;
648 			xdp->rxq->mem = frame->mem;
649 			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
650 				frame = &orig_frame;
651 				stats->rx_drops++;
652 				goto err_xdp;
653 			}
654 			stats->xdp_redirect++;
655 			rcu_read_unlock();
656 			goto xdp_xmit;
657 		default:
658 			bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
659 			fallthrough;
660 		case XDP_ABORTED:
661 			trace_xdp_exception(rq->dev, xdp_prog, act);
662 			fallthrough;
663 		case XDP_DROP:
664 			stats->xdp_drops++;
665 			goto err_xdp;
666 		}
667 	}
668 	rcu_read_unlock();
669 
670 	return frame;
671 err_xdp:
672 	rcu_read_unlock();
673 	xdp_return_frame(frame);
674 xdp_xmit:
675 	return NULL;
676 }
677 
678 /* 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)679 static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
680 				  int n_xdpf, struct veth_xdp_tx_bq *bq,
681 				  struct veth_stats *stats)
682 {
683 	void *skbs[VETH_XDP_BATCH];
684 	int i;
685 
686 	if (xdp_alloc_skb_bulk(skbs, n_xdpf,
687 			       GFP_ATOMIC | __GFP_ZERO) < 0) {
688 		for (i = 0; i < n_xdpf; i++)
689 			xdp_return_frame(frames[i]);
690 		stats->rx_drops += n_xdpf;
691 
692 		return;
693 	}
694 
695 	for (i = 0; i < n_xdpf; i++) {
696 		struct sk_buff *skb = skbs[i];
697 
698 		skb = __xdp_build_skb_from_frame(frames[i], skb,
699 						 rq->dev);
700 		if (!skb) {
701 			xdp_return_frame(frames[i]);
702 			stats->rx_drops++;
703 			continue;
704 		}
705 		napi_gro_receive(&rq->xdp_napi, skb);
706 	}
707 }
708 
veth_xdp_get(struct xdp_buff * xdp)709 static void veth_xdp_get(struct xdp_buff *xdp)
710 {
711 	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
712 	int i;
713 
714 	get_page(virt_to_page(xdp->data));
715 	if (likely(!xdp_buff_has_frags(xdp)))
716 		return;
717 
718 	for (i = 0; i < sinfo->nr_frags; i++)
719 		__skb_frag_ref(&sinfo->frags[i]);
720 }
721 
veth_convert_skb_to_xdp_buff(struct veth_rq * rq,struct xdp_buff * xdp,struct sk_buff ** pskb)722 static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
723 					struct xdp_buff *xdp,
724 					struct sk_buff **pskb)
725 {
726 	struct sk_buff *skb = *pskb;
727 	u32 frame_sz;
728 
729 	if (skb_shared(skb) || skb_head_is_locked(skb) ||
730 	    skb_shinfo(skb)->nr_frags ||
731 	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
732 		u32 size, len, max_head_size, off;
733 		struct sk_buff *nskb;
734 		struct page *page;
735 		int i, head_off;
736 
737 		/* We need a private copy of the skb and data buffers since
738 		 * the ebpf program can modify it. We segment the original skb
739 		 * into order-0 pages without linearize it.
740 		 *
741 		 * Make sure we have enough space for linear and paged area
742 		 */
743 		max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
744 						  VETH_XDP_HEADROOM);
745 		if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
746 			goto drop;
747 
748 		/* Allocate skb head */
749 		page = page_pool_dev_alloc_pages(rq->page_pool);
750 		if (!page)
751 			goto drop;
752 
753 		nskb = napi_build_skb(page_address(page), PAGE_SIZE);
754 		if (!nskb) {
755 			page_pool_put_full_page(rq->page_pool, page, true);
756 			goto drop;
757 		}
758 
759 		skb_reserve(nskb, VETH_XDP_HEADROOM);
760 		skb_copy_header(nskb, skb);
761 		skb_mark_for_recycle(nskb);
762 
763 		size = min_t(u32, skb->len, max_head_size);
764 		if (skb_copy_bits(skb, 0, nskb->data, size)) {
765 			consume_skb(nskb);
766 			goto drop;
767 		}
768 		skb_put(nskb, size);
769 
770 		head_off = skb_headroom(nskb) - skb_headroom(skb);
771 		skb_headers_offset_update(nskb, head_off);
772 
773 		/* Allocate paged area of new skb */
774 		off = size;
775 		len = skb->len - off;
776 
777 		for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
778 			page = page_pool_dev_alloc_pages(rq->page_pool);
779 			if (!page) {
780 				consume_skb(nskb);
781 				goto drop;
782 			}
783 
784 			size = min_t(u32, len, PAGE_SIZE);
785 			skb_add_rx_frag(nskb, i, page, 0, size, PAGE_SIZE);
786 			if (skb_copy_bits(skb, off, page_address(page),
787 					  size)) {
788 				consume_skb(nskb);
789 				goto drop;
790 			}
791 
792 			len -= size;
793 			off += size;
794 		}
795 
796 		consume_skb(skb);
797 		skb = nskb;
798 	}
799 
800 	/* SKB "head" area always have tailroom for skb_shared_info */
801 	frame_sz = skb_end_pointer(skb) - skb->head;
802 	frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
803 	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
804 	xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
805 			 skb_headlen(skb), true);
806 
807 	if (skb_is_nonlinear(skb)) {
808 		skb_shinfo(skb)->xdp_frags_size = skb->data_len;
809 		xdp_buff_set_frags_flag(xdp);
810 	} else {
811 		xdp_buff_clear_frags_flag(xdp);
812 	}
813 	*pskb = skb;
814 
815 	return 0;
816 drop:
817 	consume_skb(skb);
818 	*pskb = NULL;
819 
820 	return -ENOMEM;
821 }
822 
veth_xdp_rcv_skb(struct veth_rq * rq,struct sk_buff * skb,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)823 static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
824 					struct sk_buff *skb,
825 					struct veth_xdp_tx_bq *bq,
826 					struct veth_stats *stats)
827 {
828 	void *orig_data, *orig_data_end;
829 	struct bpf_prog *xdp_prog;
830 	struct veth_xdp_buff vxbuf;
831 	struct xdp_buff *xdp = &vxbuf.xdp;
832 	u32 act, metalen;
833 	int off;
834 
835 	skb_prepare_for_gro(skb);
836 
837 	rcu_read_lock();
838 	xdp_prog = rcu_dereference(rq->xdp_prog);
839 	if (unlikely(!xdp_prog)) {
840 		rcu_read_unlock();
841 		goto out;
842 	}
843 
844 	__skb_push(skb, skb->data - skb_mac_header(skb));
845 	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
846 		goto drop;
847 	vxbuf.skb = skb;
848 
849 	orig_data = xdp->data;
850 	orig_data_end = xdp->data_end;
851 
852 	act = bpf_prog_run_xdp(xdp_prog, xdp);
853 
854 	switch (act) {
855 	case XDP_PASS:
856 		break;
857 	case XDP_TX:
858 		veth_xdp_get(xdp);
859 		consume_skb(skb);
860 		xdp->rxq->mem = rq->xdp_mem;
861 		if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
862 			trace_xdp_exception(rq->dev, xdp_prog, act);
863 			stats->rx_drops++;
864 			goto err_xdp;
865 		}
866 		stats->xdp_tx++;
867 		rcu_read_unlock();
868 		goto xdp_xmit;
869 	case XDP_REDIRECT:
870 		veth_xdp_get(xdp);
871 		consume_skb(skb);
872 		xdp->rxq->mem = rq->xdp_mem;
873 		if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
874 			stats->rx_drops++;
875 			goto err_xdp;
876 		}
877 		stats->xdp_redirect++;
878 		rcu_read_unlock();
879 		goto xdp_xmit;
880 	default:
881 		bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
882 		fallthrough;
883 	case XDP_ABORTED:
884 		trace_xdp_exception(rq->dev, xdp_prog, act);
885 		fallthrough;
886 	case XDP_DROP:
887 		stats->xdp_drops++;
888 		goto xdp_drop;
889 	}
890 	rcu_read_unlock();
891 
892 	/* check if bpf_xdp_adjust_head was used */
893 	off = orig_data - xdp->data;
894 	if (off > 0)
895 		__skb_push(skb, off);
896 	else if (off < 0)
897 		__skb_pull(skb, -off);
898 
899 	skb_reset_mac_header(skb);
900 
901 	/* check if bpf_xdp_adjust_tail was used */
902 	off = xdp->data_end - orig_data_end;
903 	if (off != 0)
904 		__skb_put(skb, off); /* positive on grow, negative on shrink */
905 
906 	/* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
907 	 * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
908 	 */
909 	if (xdp_buff_has_frags(xdp))
910 		skb->data_len = skb_shinfo(skb)->xdp_frags_size;
911 	else
912 		skb->data_len = 0;
913 
914 	skb->protocol = eth_type_trans(skb, rq->dev);
915 
916 	metalen = xdp->data - xdp->data_meta;
917 	if (metalen)
918 		skb_metadata_set(skb, metalen);
919 out:
920 	return skb;
921 drop:
922 	stats->rx_drops++;
923 xdp_drop:
924 	rcu_read_unlock();
925 	kfree_skb(skb);
926 	return NULL;
927 err_xdp:
928 	rcu_read_unlock();
929 	xdp_return_buff(xdp);
930 xdp_xmit:
931 	return NULL;
932 }
933 
veth_xdp_rcv(struct veth_rq * rq,int budget,struct veth_xdp_tx_bq * bq,struct veth_stats * stats)934 static int veth_xdp_rcv(struct veth_rq *rq, int budget,
935 			struct veth_xdp_tx_bq *bq,
936 			struct veth_stats *stats)
937 {
938 	int i, done = 0, n_xdpf = 0;
939 	void *xdpf[VETH_XDP_BATCH];
940 
941 	for (i = 0; i < budget; i++) {
942 		void *ptr = __ptr_ring_consume(&rq->xdp_ring);
943 
944 		if (!ptr)
945 			break;
946 
947 		if (veth_is_xdp_frame(ptr)) {
948 			/* ndo_xdp_xmit */
949 			struct xdp_frame *frame = veth_ptr_to_xdp(ptr);
950 
951 			stats->xdp_bytes += xdp_get_frame_len(frame);
952 			frame = veth_xdp_rcv_one(rq, frame, bq, stats);
953 			if (frame) {
954 				/* XDP_PASS */
955 				xdpf[n_xdpf++] = frame;
956 				if (n_xdpf == VETH_XDP_BATCH) {
957 					veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
958 							      bq, stats);
959 					n_xdpf = 0;
960 				}
961 			}
962 		} else {
963 			/* ndo_start_xmit */
964 			struct sk_buff *skb = ptr;
965 
966 			stats->xdp_bytes += skb->len;
967 			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
968 			if (skb) {
969 				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
970 					netif_receive_skb(skb);
971 				else
972 					napi_gro_receive(&rq->xdp_napi, skb);
973 			}
974 		}
975 		done++;
976 	}
977 
978 	if (n_xdpf)
979 		veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);
980 
981 	u64_stats_update_begin(&rq->stats.syncp);
982 	rq->stats.vs.xdp_redirect += stats->xdp_redirect;
983 	rq->stats.vs.xdp_bytes += stats->xdp_bytes;
984 	rq->stats.vs.xdp_drops += stats->xdp_drops;
985 	rq->stats.vs.rx_drops += stats->rx_drops;
986 	rq->stats.vs.xdp_packets += done;
987 	u64_stats_update_end(&rq->stats.syncp);
988 
989 	return done;
990 }
991 
veth_poll(struct napi_struct * napi,int budget)992 static int veth_poll(struct napi_struct *napi, int budget)
993 {
994 	struct veth_rq *rq =
995 		container_of(napi, struct veth_rq, xdp_napi);
996 	struct veth_stats stats = {};
997 	struct veth_xdp_tx_bq bq;
998 	int done;
999 
1000 	bq.count = 0;
1001 
1002 	xdp_set_return_frame_no_direct();
1003 	done = veth_xdp_rcv(rq, budget, &bq, &stats);
1004 
1005 	if (stats.xdp_redirect > 0)
1006 		xdp_do_flush();
1007 
1008 	if (done < budget && napi_complete_done(napi, done)) {
1009 		/* Write rx_notify_masked before reading ptr_ring */
1010 		smp_store_mb(rq->rx_notify_masked, false);
1011 		if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
1012 			if (napi_schedule_prep(&rq->xdp_napi)) {
1013 				WRITE_ONCE(rq->rx_notify_masked, true);
1014 				__napi_schedule(&rq->xdp_napi);
1015 			}
1016 		}
1017 	}
1018 
1019 	if (stats.xdp_tx > 0)
1020 		veth_xdp_flush(rq, &bq);
1021 	xdp_clear_return_frame_no_direct();
1022 
1023 	return done;
1024 }
1025 
veth_create_page_pool(struct veth_rq * rq)1026 static int veth_create_page_pool(struct veth_rq *rq)
1027 {
1028 	struct page_pool_params pp_params = {
1029 		.order = 0,
1030 		.pool_size = VETH_RING_SIZE,
1031 		.nid = NUMA_NO_NODE,
1032 		.dev = &rq->dev->dev,
1033 	};
1034 
1035 	rq->page_pool = page_pool_create(&pp_params);
1036 	if (IS_ERR(rq->page_pool)) {
1037 		int err = PTR_ERR(rq->page_pool);
1038 
1039 		rq->page_pool = NULL;
1040 		return err;
1041 	}
1042 
1043 	return 0;
1044 }
1045 
__veth_napi_enable_range(struct net_device * dev,int start,int end)1046 static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
1047 {
1048 	struct veth_priv *priv = netdev_priv(dev);
1049 	int err, i;
1050 
1051 	for (i = start; i < end; i++) {
1052 		err = veth_create_page_pool(&priv->rq[i]);
1053 		if (err)
1054 			goto err_page_pool;
1055 	}
1056 
1057 	for (i = start; i < end; i++) {
1058 		struct veth_rq *rq = &priv->rq[i];
1059 
1060 		err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
1061 		if (err)
1062 			goto err_xdp_ring;
1063 	}
1064 
1065 	for (i = start; i < end; i++) {
1066 		struct veth_rq *rq = &priv->rq[i];
1067 
1068 		napi_enable(&rq->xdp_napi);
1069 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1070 	}
1071 
1072 	return 0;
1073 
1074 err_xdp_ring:
1075 	for (i--; i >= start; i--)
1076 		ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
1077 	i = end;
1078 err_page_pool:
1079 	for (i--; i >= start; i--) {
1080 		page_pool_destroy(priv->rq[i].page_pool);
1081 		priv->rq[i].page_pool = NULL;
1082 	}
1083 
1084 	return err;
1085 }
1086 
__veth_napi_enable(struct net_device * dev)1087 static int __veth_napi_enable(struct net_device *dev)
1088 {
1089 	return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1090 }
1091 
veth_napi_del_range(struct net_device * dev,int start,int end)1092 static void veth_napi_del_range(struct net_device *dev, int start, int end)
1093 {
1094 	struct veth_priv *priv = netdev_priv(dev);
1095 	int i;
1096 
1097 	for (i = start; i < end; i++) {
1098 		struct veth_rq *rq = &priv->rq[i];
1099 
1100 		rcu_assign_pointer(priv->rq[i].napi, NULL);
1101 		napi_disable(&rq->xdp_napi);
1102 		__netif_napi_del(&rq->xdp_napi);
1103 	}
1104 	synchronize_net();
1105 
1106 	for (i = start; i < end; i++) {
1107 		struct veth_rq *rq = &priv->rq[i];
1108 
1109 		rq->rx_notify_masked = false;
1110 		ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
1111 	}
1112 
1113 	for (i = start; i < end; i++) {
1114 		page_pool_destroy(priv->rq[i].page_pool);
1115 		priv->rq[i].page_pool = NULL;
1116 	}
1117 }
1118 
veth_napi_del(struct net_device * dev)1119 static void veth_napi_del(struct net_device *dev)
1120 {
1121 	veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
1122 }
1123 
veth_gro_requested(const struct net_device * dev)1124 static bool veth_gro_requested(const struct net_device *dev)
1125 {
1126 	return !!(dev->wanted_features & NETIF_F_GRO);
1127 }
1128 
veth_enable_xdp_range(struct net_device * dev,int start,int end,bool napi_already_on)1129 static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
1130 				 bool napi_already_on)
1131 {
1132 	struct veth_priv *priv = netdev_priv(dev);
1133 	int err, i;
1134 
1135 	for (i = start; i < end; i++) {
1136 		struct veth_rq *rq = &priv->rq[i];
1137 
1138 		if (!napi_already_on)
1139 			netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1140 		err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
1141 		if (err < 0)
1142 			goto err_rxq_reg;
1143 
1144 		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
1145 						 MEM_TYPE_PAGE_SHARED,
1146 						 NULL);
1147 		if (err < 0)
1148 			goto err_reg_mem;
1149 
1150 		/* Save original mem info as it can be overwritten */
1151 		rq->xdp_mem = rq->xdp_rxq.mem;
1152 	}
1153 	return 0;
1154 
1155 err_reg_mem:
1156 	xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
1157 err_rxq_reg:
1158 	for (i--; i >= start; i--) {
1159 		struct veth_rq *rq = &priv->rq[i];
1160 
1161 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1162 		if (!napi_already_on)
1163 			netif_napi_del(&rq->xdp_napi);
1164 	}
1165 
1166 	return err;
1167 }
1168 
veth_disable_xdp_range(struct net_device * dev,int start,int end,bool delete_napi)1169 static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
1170 				   bool delete_napi)
1171 {
1172 	struct veth_priv *priv = netdev_priv(dev);
1173 	int i;
1174 
1175 	for (i = start; i < end; i++) {
1176 		struct veth_rq *rq = &priv->rq[i];
1177 
1178 		rq->xdp_rxq.mem = rq->xdp_mem;
1179 		xdp_rxq_info_unreg(&rq->xdp_rxq);
1180 
1181 		if (delete_napi)
1182 			netif_napi_del(&rq->xdp_napi);
1183 	}
1184 }
1185 
veth_enable_xdp(struct net_device * dev)1186 static int veth_enable_xdp(struct net_device *dev)
1187 {
1188 	bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
1189 	struct veth_priv *priv = netdev_priv(dev);
1190 	int err, i;
1191 
1192 	if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
1193 		err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
1194 		if (err)
1195 			return err;
1196 
1197 		if (!napi_already_on) {
1198 			err = __veth_napi_enable(dev);
1199 			if (err) {
1200 				veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
1201 				return err;
1202 			}
1203 		}
1204 	}
1205 
1206 	for (i = 0; i < dev->real_num_rx_queues; i++) {
1207 		rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
1208 		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
1209 	}
1210 
1211 	return 0;
1212 }
1213 
veth_disable_xdp(struct net_device * dev)1214 static void veth_disable_xdp(struct net_device *dev)
1215 {
1216 	struct veth_priv *priv = netdev_priv(dev);
1217 	int i;
1218 
1219 	for (i = 0; i < dev->real_num_rx_queues; i++)
1220 		rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);
1221 
1222 	if (!netif_running(dev) || !veth_gro_requested(dev))
1223 		veth_napi_del(dev);
1224 
1225 	veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
1226 }
1227 
veth_napi_enable_range(struct net_device * dev,int start,int end)1228 static int veth_napi_enable_range(struct net_device *dev, int start, int end)
1229 {
1230 	struct veth_priv *priv = netdev_priv(dev);
1231 	int err, i;
1232 
1233 	for (i = start; i < end; i++) {
1234 		struct veth_rq *rq = &priv->rq[i];
1235 
1236 		netif_napi_add(dev, &rq->xdp_napi, veth_poll);
1237 	}
1238 
1239 	err = __veth_napi_enable_range(dev, start, end);
1240 	if (err) {
1241 		for (i = start; i < end; i++) {
1242 			struct veth_rq *rq = &priv->rq[i];
1243 
1244 			netif_napi_del(&rq->xdp_napi);
1245 		}
1246 		return err;
1247 	}
1248 	return err;
1249 }
1250 
veth_napi_enable(struct net_device * dev)1251 static int veth_napi_enable(struct net_device *dev)
1252 {
1253 	return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
1254 }
1255 
veth_disable_range_safe(struct net_device * dev,int start,int end)1256 static void veth_disable_range_safe(struct net_device *dev, int start, int end)
1257 {
1258 	struct veth_priv *priv = netdev_priv(dev);
1259 
1260 	if (start >= end)
1261 		return;
1262 
1263 	if (priv->_xdp_prog) {
1264 		veth_napi_del_range(dev, start, end);
1265 		veth_disable_xdp_range(dev, start, end, false);
1266 	} else if (veth_gro_requested(dev)) {
1267 		veth_napi_del_range(dev, start, end);
1268 	}
1269 }
1270 
veth_enable_range_safe(struct net_device * dev,int start,int end)1271 static int veth_enable_range_safe(struct net_device *dev, int start, int end)
1272 {
1273 	struct veth_priv *priv = netdev_priv(dev);
1274 	int err;
1275 
1276 	if (start >= end)
1277 		return 0;
1278 
1279 	if (priv->_xdp_prog) {
1280 		/* these channels are freshly initialized, napi is not on there even
1281 		 * when GRO is requeste
1282 		 */
1283 		err = veth_enable_xdp_range(dev, start, end, false);
1284 		if (err)
1285 			return err;
1286 
1287 		err = __veth_napi_enable_range(dev, start, end);
1288 		if (err) {
1289 			/* on error always delete the newly added napis */
1290 			veth_disable_xdp_range(dev, start, end, true);
1291 			return err;
1292 		}
1293 	} else if (veth_gro_requested(dev)) {
1294 		return veth_napi_enable_range(dev, start, end);
1295 	}
1296 	return 0;
1297 }
1298 
veth_set_xdp_features(struct net_device * dev)1299 static void veth_set_xdp_features(struct net_device *dev)
1300 {
1301 	struct veth_priv *priv = netdev_priv(dev);
1302 	struct net_device *peer;
1303 
1304 	peer = rtnl_dereference(priv->peer);
1305 	if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
1306 		struct veth_priv *priv_peer = netdev_priv(peer);
1307 		xdp_features_t val = NETDEV_XDP_ACT_BASIC |
1308 				     NETDEV_XDP_ACT_REDIRECT |
1309 				     NETDEV_XDP_ACT_RX_SG;
1310 
1311 		if (priv_peer->_xdp_prog || veth_gro_requested(peer))
1312 			val |= NETDEV_XDP_ACT_NDO_XMIT |
1313 			       NETDEV_XDP_ACT_NDO_XMIT_SG;
1314 		xdp_set_features_flag(dev, val);
1315 	} else {
1316 		xdp_clear_features_flag(dev);
1317 	}
1318 }
1319 
veth_set_channels(struct net_device * dev,struct ethtool_channels * ch)1320 static int veth_set_channels(struct net_device *dev,
1321 			     struct ethtool_channels *ch)
1322 {
1323 	struct veth_priv *priv = netdev_priv(dev);
1324 	unsigned int old_rx_count, new_rx_count;
1325 	struct veth_priv *peer_priv;
1326 	struct net_device *peer;
1327 	int err;
1328 
1329 	/* sanity check. Upper bounds are already enforced by the caller */
1330 	if (!ch->rx_count || !ch->tx_count)
1331 		return -EINVAL;
1332 
1333 	/* avoid braking XDP, if that is enabled */
1334 	peer = rtnl_dereference(priv->peer);
1335 	peer_priv = peer ? netdev_priv(peer) : NULL;
1336 	if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
1337 		return -EINVAL;
1338 
1339 	if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
1340 		return -EINVAL;
1341 
1342 	old_rx_count = dev->real_num_rx_queues;
1343 	new_rx_count = ch->rx_count;
1344 	if (netif_running(dev)) {
1345 		/* turn device off */
1346 		netif_carrier_off(dev);
1347 		if (peer)
1348 			netif_carrier_off(peer);
1349 
1350 		/* try to allocate new resurces, as needed*/
1351 		err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
1352 		if (err)
1353 			goto out;
1354 	}
1355 
1356 	err = netif_set_real_num_rx_queues(dev, ch->rx_count);
1357 	if (err)
1358 		goto revert;
1359 
1360 	err = netif_set_real_num_tx_queues(dev, ch->tx_count);
1361 	if (err) {
1362 		int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);
1363 
1364 		/* this error condition could happen only if rx and tx change
1365 		 * in opposite directions (e.g. tx nr raises, rx nr decreases)
1366 		 * and we can't do anything to fully restore the original
1367 		 * status
1368 		 */
1369 		if (err2)
1370 			pr_warn("Can't restore rx queues config %d -> %d %d",
1371 				new_rx_count, old_rx_count, err2);
1372 		else
1373 			goto revert;
1374 	}
1375 
1376 out:
1377 	if (netif_running(dev)) {
1378 		/* note that we need to swap the arguments WRT the enable part
1379 		 * to identify the range we have to disable
1380 		 */
1381 		veth_disable_range_safe(dev, new_rx_count, old_rx_count);
1382 		netif_carrier_on(dev);
1383 		if (peer)
1384 			netif_carrier_on(peer);
1385 	}
1386 
1387 	/* update XDP supported features */
1388 	veth_set_xdp_features(dev);
1389 	if (peer)
1390 		veth_set_xdp_features(peer);
1391 
1392 	return err;
1393 
1394 revert:
1395 	new_rx_count = old_rx_count;
1396 	old_rx_count = ch->rx_count;
1397 	goto out;
1398 }
1399 
veth_open(struct net_device * dev)1400 static int veth_open(struct net_device *dev)
1401 {
1402 	struct veth_priv *priv = netdev_priv(dev);
1403 	struct net_device *peer = rtnl_dereference(priv->peer);
1404 	int err;
1405 
1406 	if (!peer)
1407 		return -ENOTCONN;
1408 
1409 	if (priv->_xdp_prog) {
1410 		err = veth_enable_xdp(dev);
1411 		if (err)
1412 			return err;
1413 	} else if (veth_gro_requested(dev)) {
1414 		err = veth_napi_enable(dev);
1415 		if (err)
1416 			return err;
1417 	}
1418 
1419 	if (peer->flags & IFF_UP) {
1420 		netif_carrier_on(dev);
1421 		netif_carrier_on(peer);
1422 	}
1423 
1424 	veth_set_xdp_features(dev);
1425 
1426 	return 0;
1427 }
1428 
veth_close(struct net_device * dev)1429 static int veth_close(struct net_device *dev)
1430 {
1431 	struct veth_priv *priv = netdev_priv(dev);
1432 	struct net_device *peer = rtnl_dereference(priv->peer);
1433 
1434 	netif_carrier_off(dev);
1435 	if (peer)
1436 		netif_carrier_off(peer);
1437 
1438 	if (priv->_xdp_prog)
1439 		veth_disable_xdp(dev);
1440 	else if (veth_gro_requested(dev))
1441 		veth_napi_del(dev);
1442 
1443 	return 0;
1444 }
1445 
is_valid_veth_mtu(int mtu)1446 static int is_valid_veth_mtu(int mtu)
1447 {
1448 	return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
1449 }
1450 
veth_alloc_queues(struct net_device * dev)1451 static int veth_alloc_queues(struct net_device *dev)
1452 {
1453 	struct veth_priv *priv = netdev_priv(dev);
1454 	int i;
1455 
1456 	priv->rq = kvcalloc(dev->num_rx_queues, sizeof(*priv->rq),
1457 			    GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL);
1458 	if (!priv->rq)
1459 		return -ENOMEM;
1460 
1461 	for (i = 0; i < dev->num_rx_queues; i++) {
1462 		priv->rq[i].dev = dev;
1463 		u64_stats_init(&priv->rq[i].stats.syncp);
1464 	}
1465 
1466 	return 0;
1467 }
1468 
veth_free_queues(struct net_device * dev)1469 static void veth_free_queues(struct net_device *dev)
1470 {
1471 	struct veth_priv *priv = netdev_priv(dev);
1472 
1473 	kvfree(priv->rq);
1474 }
1475 
veth_dev_init(struct net_device * dev)1476 static int veth_dev_init(struct net_device *dev)
1477 {
1478 	netdev_lockdep_set_classes(dev);
1479 	return veth_alloc_queues(dev);
1480 }
1481 
veth_dev_free(struct net_device * dev)1482 static void veth_dev_free(struct net_device *dev)
1483 {
1484 	veth_free_queues(dev);
1485 }
1486 
1487 #ifdef CONFIG_NET_POLL_CONTROLLER
veth_poll_controller(struct net_device * dev)1488 static void veth_poll_controller(struct net_device *dev)
1489 {
1490 	/* veth only receives frames when its peer sends one
1491 	 * Since it has nothing to do with disabling irqs, we are guaranteed
1492 	 * never to have pending data when we poll for it so
1493 	 * there is nothing to do here.
1494 	 *
1495 	 * We need this though so netpoll recognizes us as an interface that
1496 	 * supports polling, which enables bridge devices in virt setups to
1497 	 * still use netconsole
1498 	 */
1499 }
1500 #endif	/* CONFIG_NET_POLL_CONTROLLER */
1501 
veth_get_iflink(const struct net_device * dev)1502 static int veth_get_iflink(const struct net_device *dev)
1503 {
1504 	struct veth_priv *priv = netdev_priv(dev);
1505 	struct net_device *peer;
1506 	int iflink;
1507 
1508 	rcu_read_lock();
1509 	peer = rcu_dereference(priv->peer);
1510 	iflink = peer ? peer->ifindex : 0;
1511 	rcu_read_unlock();
1512 
1513 	return iflink;
1514 }
1515 
veth_fix_features(struct net_device * dev,netdev_features_t features)1516 static netdev_features_t veth_fix_features(struct net_device *dev,
1517 					   netdev_features_t features)
1518 {
1519 	struct veth_priv *priv = netdev_priv(dev);
1520 	struct net_device *peer;
1521 
1522 	peer = rtnl_dereference(priv->peer);
1523 	if (peer) {
1524 		struct veth_priv *peer_priv = netdev_priv(peer);
1525 
1526 		if (peer_priv->_xdp_prog)
1527 			features &= ~NETIF_F_GSO_SOFTWARE;
1528 	}
1529 
1530 	return features;
1531 }
1532 
veth_set_features(struct net_device * dev,netdev_features_t features)1533 static int veth_set_features(struct net_device *dev,
1534 			     netdev_features_t features)
1535 {
1536 	netdev_features_t changed = features ^ dev->features;
1537 	struct veth_priv *priv = netdev_priv(dev);
1538 	struct net_device *peer;
1539 	int err;
1540 
1541 	if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
1542 		return 0;
1543 
1544 	peer = rtnl_dereference(priv->peer);
1545 	if (features & NETIF_F_GRO) {
1546 		err = veth_napi_enable(dev);
1547 		if (err)
1548 			return err;
1549 
1550 		if (peer)
1551 			xdp_features_set_redirect_target(peer, true);
1552 	} else {
1553 		if (peer)
1554 			xdp_features_clear_redirect_target(peer);
1555 		veth_napi_del(dev);
1556 	}
1557 	return 0;
1558 }
1559 
veth_set_rx_headroom(struct net_device * dev,int new_hr)1560 static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
1561 {
1562 	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
1563 	struct net_device *peer;
1564 
1565 	if (new_hr < 0)
1566 		new_hr = 0;
1567 
1568 	rcu_read_lock();
1569 	peer = rcu_dereference(priv->peer);
1570 	if (unlikely(!peer))
1571 		goto out;
1572 
1573 	peer_priv = netdev_priv(peer);
1574 	priv->requested_headroom = new_hr;
1575 	new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
1576 	dev->needed_headroom = new_hr;
1577 	peer->needed_headroom = new_hr;
1578 
1579 out:
1580 	rcu_read_unlock();
1581 }
1582 
veth_xdp_set(struct net_device * dev,struct bpf_prog * prog,struct netlink_ext_ack * extack)1583 static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
1584 			struct netlink_ext_ack *extack)
1585 {
1586 	struct veth_priv *priv = netdev_priv(dev);
1587 	struct bpf_prog *old_prog;
1588 	struct net_device *peer;
1589 	unsigned int max_mtu;
1590 	int err;
1591 
1592 	old_prog = priv->_xdp_prog;
1593 	priv->_xdp_prog = prog;
1594 	peer = rtnl_dereference(priv->peer);
1595 
1596 	if (prog) {
1597 		if (!peer) {
1598 			NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
1599 			err = -ENOTCONN;
1600 			goto err;
1601 		}
1602 
1603 		max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
1604 			  peer->hard_header_len;
1605 		/* Allow increasing the max_mtu if the program supports
1606 		 * XDP fragments.
1607 		 */
1608 		if (prog->aux->xdp_has_frags)
1609 			max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;
1610 
1611 		if (peer->mtu > max_mtu) {
1612 			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
1613 			err = -ERANGE;
1614 			goto err;
1615 		}
1616 
1617 		if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
1618 			NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
1619 			err = -ENOSPC;
1620 			goto err;
1621 		}
1622 
1623 		if (dev->flags & IFF_UP) {
1624 			err = veth_enable_xdp(dev);
1625 			if (err) {
1626 				NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
1627 				goto err;
1628 			}
1629 		}
1630 
1631 		if (!old_prog) {
1632 			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
1633 			peer->max_mtu = max_mtu;
1634 		}
1635 
1636 		xdp_features_set_redirect_target(peer, true);
1637 	}
1638 
1639 	if (old_prog) {
1640 		if (!prog) {
1641 			if (peer && !veth_gro_requested(dev))
1642 				xdp_features_clear_redirect_target(peer);
1643 
1644 			if (dev->flags & IFF_UP)
1645 				veth_disable_xdp(dev);
1646 
1647 			if (peer) {
1648 				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
1649 				peer->max_mtu = ETH_MAX_MTU;
1650 			}
1651 		}
1652 		bpf_prog_put(old_prog);
1653 	}
1654 
1655 	if ((!!old_prog ^ !!prog) && peer)
1656 		netdev_update_features(peer);
1657 
1658 	return 0;
1659 err:
1660 	priv->_xdp_prog = old_prog;
1661 
1662 	return err;
1663 }
1664 
veth_xdp(struct net_device * dev,struct netdev_bpf * xdp)1665 static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
1666 {
1667 	switch (xdp->command) {
1668 	case XDP_SETUP_PROG:
1669 		return veth_xdp_set(dev, xdp->prog, xdp->extack);
1670 	default:
1671 		return -EINVAL;
1672 	}
1673 }
1674 
veth_xdp_rx_timestamp(const struct xdp_md * ctx,u64 * timestamp)1675 static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
1676 {
1677 	struct veth_xdp_buff *_ctx = (void *)ctx;
1678 
1679 	if (!_ctx->skb)
1680 		return -ENODATA;
1681 
1682 	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
1683 	return 0;
1684 }
1685 
veth_xdp_rx_hash(const struct xdp_md * ctx,u32 * hash,enum xdp_rss_hash_type * rss_type)1686 static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
1687 			    enum xdp_rss_hash_type *rss_type)
1688 {
1689 	struct veth_xdp_buff *_ctx = (void *)ctx;
1690 	struct sk_buff *skb = _ctx->skb;
1691 
1692 	if (!skb)
1693 		return -ENODATA;
1694 
1695 	*hash = skb_get_hash(skb);
1696 	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;
1697 
1698 	return 0;
1699 }
1700 
1701 static const struct net_device_ops veth_netdev_ops = {
1702 	.ndo_init            = veth_dev_init,
1703 	.ndo_open            = veth_open,
1704 	.ndo_stop            = veth_close,
1705 	.ndo_start_xmit      = veth_xmit,
1706 	.ndo_get_stats64     = veth_get_stats64,
1707 	.ndo_set_rx_mode     = veth_set_multicast_list,
1708 	.ndo_set_mac_address = eth_mac_addr,
1709 #ifdef CONFIG_NET_POLL_CONTROLLER
1710 	.ndo_poll_controller	= veth_poll_controller,
1711 #endif
1712 	.ndo_get_iflink		= veth_get_iflink,
1713 	.ndo_fix_features	= veth_fix_features,
1714 	.ndo_set_features	= veth_set_features,
1715 	.ndo_features_check	= passthru_features_check,
1716 	.ndo_set_rx_headroom	= veth_set_rx_headroom,
1717 	.ndo_bpf		= veth_xdp,
1718 	.ndo_xdp_xmit		= veth_ndo_xdp_xmit,
1719 	.ndo_get_peer_dev	= veth_peer_dev,
1720 };
1721 
1722 static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
1723 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
1724 	.xmo_rx_hash			= veth_xdp_rx_hash,
1725 };
1726 
1727 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
1728 		       NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
1729 		       NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
1730 		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
1731 		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )
1732 
veth_setup(struct net_device * dev)1733 static void veth_setup(struct net_device *dev)
1734 {
1735 	ether_setup(dev);
1736 
1737 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1738 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1739 	dev->priv_flags |= IFF_NO_QUEUE;
1740 	dev->priv_flags |= IFF_PHONY_HEADROOM;
1741 
1742 	dev->netdev_ops = &veth_netdev_ops;
1743 	dev->xdp_metadata_ops = &veth_xdp_metadata_ops;
1744 	dev->ethtool_ops = &veth_ethtool_ops;
1745 	dev->features |= NETIF_F_LLTX;
1746 	dev->features |= VETH_FEATURES;
1747 	dev->vlan_features = dev->features &
1748 			     ~(NETIF_F_HW_VLAN_CTAG_TX |
1749 			       NETIF_F_HW_VLAN_STAG_TX |
1750 			       NETIF_F_HW_VLAN_CTAG_RX |
1751 			       NETIF_F_HW_VLAN_STAG_RX);
1752 	dev->needs_free_netdev = true;
1753 	dev->priv_destructor = veth_dev_free;
1754 	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
1755 	dev->max_mtu = ETH_MAX_MTU;
1756 
1757 	dev->hw_features = VETH_FEATURES;
1758 	dev->hw_enc_features = VETH_FEATURES;
1759 	dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
1760 	netif_set_tso_max_size(dev, GSO_MAX_SIZE);
1761 }
1762 
1763 /*
1764  * netlink interface
1765  */
1766 
veth_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1767 static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
1768 			 struct netlink_ext_ack *extack)
1769 {
1770 	if (tb[IFLA_ADDRESS]) {
1771 		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1772 			return -EINVAL;
1773 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1774 			return -EADDRNOTAVAIL;
1775 	}
1776 	if (tb[IFLA_MTU]) {
1777 		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
1778 			return -EINVAL;
1779 	}
1780 	return 0;
1781 }
1782 
1783 static struct rtnl_link_ops veth_link_ops;
1784 
veth_disable_gro(struct net_device * dev)1785 static void veth_disable_gro(struct net_device *dev)
1786 {
1787 	dev->features &= ~NETIF_F_GRO;
1788 	dev->wanted_features &= ~NETIF_F_GRO;
1789 	netdev_update_features(dev);
1790 }
1791 
veth_init_queues(struct net_device * dev,struct nlattr * tb[])1792 static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
1793 {
1794 	int err;
1795 
1796 	if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
1797 		err = netif_set_real_num_tx_queues(dev, 1);
1798 		if (err)
1799 			return err;
1800 	}
1801 	if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
1802 		err = netif_set_real_num_rx_queues(dev, 1);
1803 		if (err)
1804 			return err;
1805 	}
1806 	return 0;
1807 }
1808 
veth_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)1809 static int veth_newlink(struct net *src_net, struct net_device *dev,
1810 			struct nlattr *tb[], struct nlattr *data[],
1811 			struct netlink_ext_ack *extack)
1812 {
1813 	int err;
1814 	struct net_device *peer;
1815 	struct veth_priv *priv;
1816 	char ifname[IFNAMSIZ];
1817 	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
1818 	unsigned char name_assign_type;
1819 	struct ifinfomsg *ifmp;
1820 	struct net *net;
1821 
1822 	/*
1823 	 * create and register peer first
1824 	 */
1825 	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
1826 		struct nlattr *nla_peer;
1827 
1828 		nla_peer = data[VETH_INFO_PEER];
1829 		ifmp = nla_data(nla_peer);
1830 		err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack);
1831 		if (err < 0)
1832 			return err;
1833 
1834 		err = veth_validate(peer_tb, NULL, extack);
1835 		if (err < 0)
1836 			return err;
1837 
1838 		tbp = peer_tb;
1839 	} else {
1840 		ifmp = NULL;
1841 		tbp = tb;
1842 	}
1843 
1844 	if (ifmp && tbp[IFLA_IFNAME]) {
1845 		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
1846 		name_assign_type = NET_NAME_USER;
1847 	} else {
1848 		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
1849 		name_assign_type = NET_NAME_ENUM;
1850 	}
1851 
1852 	net = rtnl_link_get_net(src_net, tbp);
1853 	if (IS_ERR(net))
1854 		return PTR_ERR(net);
1855 
1856 	peer = rtnl_create_link(net, ifname, name_assign_type,
1857 				&veth_link_ops, tbp, extack);
1858 	if (IS_ERR(peer)) {
1859 		put_net(net);
1860 		return PTR_ERR(peer);
1861 	}
1862 
1863 	if (!ifmp || !tbp[IFLA_ADDRESS])
1864 		eth_hw_addr_random(peer);
1865 
1866 	if (ifmp && (dev->ifindex != 0))
1867 		peer->ifindex = ifmp->ifi_index;
1868 
1869 	netif_inherit_tso_max(peer, dev);
1870 
1871 	err = register_netdevice(peer);
1872 	put_net(net);
1873 	net = NULL;
1874 	if (err < 0)
1875 		goto err_register_peer;
1876 
1877 	/* keep GRO disabled by default to be consistent with the established
1878 	 * veth behavior
1879 	 */
1880 	veth_disable_gro(peer);
1881 	netif_carrier_off(peer);
1882 
1883 	err = rtnl_configure_link(peer, ifmp, 0, NULL);
1884 	if (err < 0)
1885 		goto err_configure_peer;
1886 
1887 	/*
1888 	 * register dev last
1889 	 *
1890 	 * note, that since we've registered new device the dev's name
1891 	 * should be re-allocated
1892 	 */
1893 
1894 	if (tb[IFLA_ADDRESS] == NULL)
1895 		eth_hw_addr_random(dev);
1896 
1897 	if (tb[IFLA_IFNAME])
1898 		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
1899 	else
1900 		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");
1901 
1902 	err = register_netdevice(dev);
1903 	if (err < 0)
1904 		goto err_register_dev;
1905 
1906 	netif_carrier_off(dev);
1907 
1908 	/*
1909 	 * tie the deviced together
1910 	 */
1911 
1912 	priv = netdev_priv(dev);
1913 	rcu_assign_pointer(priv->peer, peer);
1914 	err = veth_init_queues(dev, tb);
1915 	if (err)
1916 		goto err_queues;
1917 
1918 	priv = netdev_priv(peer);
1919 	rcu_assign_pointer(priv->peer, dev);
1920 	err = veth_init_queues(peer, tb);
1921 	if (err)
1922 		goto err_queues;
1923 
1924 	veth_disable_gro(dev);
1925 	/* update XDP supported features */
1926 	veth_set_xdp_features(dev);
1927 	veth_set_xdp_features(peer);
1928 
1929 	return 0;
1930 
1931 err_queues:
1932 	unregister_netdevice(dev);
1933 err_register_dev:
1934 	/* nothing to do */
1935 err_configure_peer:
1936 	unregister_netdevice(peer);
1937 	return err;
1938 
1939 err_register_peer:
1940 	free_netdev(peer);
1941 	return err;
1942 }
1943 
veth_dellink(struct net_device * dev,struct list_head * head)1944 static void veth_dellink(struct net_device *dev, struct list_head *head)
1945 {
1946 	struct veth_priv *priv;
1947 	struct net_device *peer;
1948 
1949 	priv = netdev_priv(dev);
1950 	peer = rtnl_dereference(priv->peer);
1951 
1952 	/* Note : dellink() is called from default_device_exit_batch(),
1953 	 * before a rcu_synchronize() point. The devices are guaranteed
1954 	 * not being freed before one RCU grace period.
1955 	 */
1956 	RCU_INIT_POINTER(priv->peer, NULL);
1957 	unregister_netdevice_queue(dev, head);
1958 
1959 	if (peer) {
1960 		priv = netdev_priv(peer);
1961 		RCU_INIT_POINTER(priv->peer, NULL);
1962 		unregister_netdevice_queue(peer, head);
1963 	}
1964 }
1965 
1966 static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
1967 	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
1968 };
1969 
veth_get_link_net(const struct net_device * dev)1970 static struct net *veth_get_link_net(const struct net_device *dev)
1971 {
1972 	struct veth_priv *priv = netdev_priv(dev);
1973 	struct net_device *peer = rtnl_dereference(priv->peer);
1974 
1975 	return peer ? dev_net(peer) : dev_net(dev);
1976 }
1977 
veth_get_num_queues(void)1978 static unsigned int veth_get_num_queues(void)
1979 {
1980 	/* enforce the same queue limit as rtnl_create_link */
1981 	int queues = num_possible_cpus();
1982 
1983 	if (queues > 4096)
1984 		queues = 4096;
1985 	return queues;
1986 }
1987 
1988 static struct rtnl_link_ops veth_link_ops = {
1989 	.kind		= DRV_NAME,
1990 	.priv_size	= sizeof(struct veth_priv),
1991 	.setup		= veth_setup,
1992 	.validate	= veth_validate,
1993 	.newlink	= veth_newlink,
1994 	.dellink	= veth_dellink,
1995 	.policy		= veth_policy,
1996 	.maxtype	= VETH_INFO_MAX,
1997 	.get_link_net	= veth_get_link_net,
1998 	.get_num_tx_queues	= veth_get_num_queues,
1999 	.get_num_rx_queues	= veth_get_num_queues,
2000 };
2001 
2002 /*
2003  * init/fini
2004  */
2005 
veth_init(void)2006 static __init int veth_init(void)
2007 {
2008 	return rtnl_link_register(&veth_link_ops);
2009 }
2010 
veth_exit(void)2011 static __exit void veth_exit(void)
2012 {
2013 	rtnl_link_unregister(&veth_link_ops);
2014 }
2015 
2016 module_init(veth_init);
2017 module_exit(veth_exit);
2018 
2019 MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
2020 MODULE_LICENSE("GPL v2");
2021 MODULE_ALIAS_RTNL_LINK(DRV_NAME);
2022