1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * xfrm_device.c - IPsec device offloading code.
4 *
5 * Copyright (c) 2015 secunet Security Networks AG
6 *
7 * Author:
8 * Steffen Klassert <steffen.klassert@secunet.com>
9 */
10
11#include <linux/errno.h>
12#include <linux/module.h>
13#include <linux/netdevice.h>
14#include <linux/skbuff.h>
15#include <linux/slab.h>
16#include <linux/spinlock.h>
17#include <net/dst.h>
18#include <net/gso.h>
19#include <net/xfrm.h>
20#include <linux/notifier.h>
21
22#ifdef CONFIG_XFRM_OFFLOAD
23static void __xfrm_transport_prep(struct xfrm_state *x, struct sk_buff *skb,
24				  unsigned int hsize)
25{
26	struct xfrm_offload *xo = xfrm_offload(skb);
27
28	skb_reset_mac_len(skb);
29	if (xo->flags & XFRM_GSO_SEGMENT)
30		skb->transport_header -= x->props.header_len;
31
32	pskb_pull(skb, skb_transport_offset(skb) + x->props.header_len);
33}
34
35static void __xfrm_mode_tunnel_prep(struct xfrm_state *x, struct sk_buff *skb,
36				    unsigned int hsize)
37
38{
39	struct xfrm_offload *xo = xfrm_offload(skb);
40
41	if (xo->flags & XFRM_GSO_SEGMENT)
42		skb->transport_header = skb->network_header + hsize;
43
44	skb_reset_mac_len(skb);
45	pskb_pull(skb, skb->mac_len + x->props.header_len);
46}
47
48static void __xfrm_mode_beet_prep(struct xfrm_state *x, struct sk_buff *skb,
49				  unsigned int hsize)
50{
51	struct xfrm_offload *xo = xfrm_offload(skb);
52	int phlen = 0;
53
54	if (xo->flags & XFRM_GSO_SEGMENT)
55		skb->transport_header = skb->network_header + hsize;
56
57	skb_reset_mac_len(skb);
58	if (x->sel.family != AF_INET6) {
59		phlen = IPV4_BEET_PHMAXLEN;
60		if (x->outer_mode.family == AF_INET6)
61			phlen += sizeof(struct ipv6hdr) - sizeof(struct iphdr);
62	}
63
64	pskb_pull(skb, skb->mac_len + hsize + (x->props.header_len - phlen));
65}
66
67/* Adjust pointers into the packet when IPsec is done at layer2 */
68static void xfrm_outer_mode_prep(struct xfrm_state *x, struct sk_buff *skb)
69{
70	switch (x->outer_mode.encap) {
71	case XFRM_MODE_TUNNEL:
72		if (x->outer_mode.family == AF_INET)
73			return __xfrm_mode_tunnel_prep(x, skb,
74						       sizeof(struct iphdr));
75		if (x->outer_mode.family == AF_INET6)
76			return __xfrm_mode_tunnel_prep(x, skb,
77						       sizeof(struct ipv6hdr));
78		break;
79	case XFRM_MODE_TRANSPORT:
80		if (x->outer_mode.family == AF_INET)
81			return __xfrm_transport_prep(x, skb,
82						     sizeof(struct iphdr));
83		if (x->outer_mode.family == AF_INET6)
84			return __xfrm_transport_prep(x, skb,
85						     sizeof(struct ipv6hdr));
86		break;
87	case XFRM_MODE_BEET:
88		if (x->outer_mode.family == AF_INET)
89			return __xfrm_mode_beet_prep(x, skb,
90						     sizeof(struct iphdr));
91		if (x->outer_mode.family == AF_INET6)
92			return __xfrm_mode_beet_prep(x, skb,
93						     sizeof(struct ipv6hdr));
94		break;
95	case XFRM_MODE_ROUTEOPTIMIZATION:
96	case XFRM_MODE_IN_TRIGGER:
97		break;
98	}
99}
100
101static inline bool xmit_xfrm_check_overflow(struct sk_buff *skb)
102{
103	struct xfrm_offload *xo = xfrm_offload(skb);
104	__u32 seq = xo->seq.low;
105
106	seq += skb_shinfo(skb)->gso_segs;
107	if (unlikely(seq < xo->seq.low))
108		return true;
109
110	return false;
111}
112
113struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
114{
115	int err;
116	unsigned long flags;
117	struct xfrm_state *x;
118	struct softnet_data *sd;
119	struct sk_buff *skb2, *nskb, *pskb = NULL;
120	netdev_features_t esp_features = features;
121	struct xfrm_offload *xo = xfrm_offload(skb);
122	struct net_device *dev = skb->dev;
123	struct sec_path *sp;
124
125	if (!xo || (xo->flags & XFRM_XMIT))
126		return skb;
127
128	if (!(features & NETIF_F_HW_ESP))
129		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
130
131	sp = skb_sec_path(skb);
132	x = sp->xvec[sp->len - 1];
133	if (xo->flags & XFRM_GRO || x->xso.dir == XFRM_DEV_OFFLOAD_IN)
134		return skb;
135
136	/* The packet was sent to HW IPsec packet offload engine,
137	 * but to wrong device. Drop the packet, so it won't skip
138	 * XFRM stack.
139	 */
140	if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET && x->xso.dev != dev) {
141		kfree_skb(skb);
142		dev_core_stats_tx_dropped_inc(dev);
143		return NULL;
144	}
145
146	/* This skb was already validated on the upper/virtual dev */
147	if ((x->xso.dev != dev) && (x->xso.real_dev == dev))
148		return skb;
149
150	local_irq_save(flags);
151	sd = this_cpu_ptr(&softnet_data);
152	err = !skb_queue_empty(&sd->xfrm_backlog);
153	local_irq_restore(flags);
154
155	if (err) {
156		*again = true;
157		return skb;
158	}
159
160	if (skb_is_gso(skb) && (unlikely(x->xso.dev != dev) ||
161				unlikely(xmit_xfrm_check_overflow(skb)))) {
162		struct sk_buff *segs;
163
164		/* Packet got rerouted, fixup features and segment it. */
165		esp_features = esp_features & ~(NETIF_F_HW_ESP | NETIF_F_GSO_ESP);
166
167		segs = skb_gso_segment(skb, esp_features);
168		if (IS_ERR(segs)) {
169			kfree_skb(skb);
170			dev_core_stats_tx_dropped_inc(dev);
171			return NULL;
172		} else {
173			consume_skb(skb);
174			skb = segs;
175		}
176	}
177
178	if (!skb->next) {
179		esp_features |= skb->dev->gso_partial_features;
180		xfrm_outer_mode_prep(x, skb);
181
182		xo->flags |= XFRM_DEV_RESUME;
183
184		err = x->type_offload->xmit(x, skb, esp_features);
185		if (err) {
186			if (err == -EINPROGRESS)
187				return NULL;
188
189			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
190			kfree_skb(skb);
191			return NULL;
192		}
193
194		skb_push(skb, skb->data - skb_mac_header(skb));
195
196		return skb;
197	}
198
199	skb_list_walk_safe(skb, skb2, nskb) {
200		esp_features |= skb->dev->gso_partial_features;
201		skb_mark_not_on_list(skb2);
202
203		xo = xfrm_offload(skb2);
204		xo->flags |= XFRM_DEV_RESUME;
205
206		xfrm_outer_mode_prep(x, skb2);
207
208		err = x->type_offload->xmit(x, skb2, esp_features);
209		if (!err) {
210			skb2->next = nskb;
211		} else if (err != -EINPROGRESS) {
212			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
213			skb2->next = nskb;
214			kfree_skb_list(skb2);
215			return NULL;
216		} else {
217			if (skb == skb2)
218				skb = nskb;
219			else
220				pskb->next = nskb;
221
222			continue;
223		}
224
225		skb_push(skb2, skb2->data - skb_mac_header(skb2));
226		pskb = skb2;
227	}
228
229	return skb;
230}
231EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
232
233int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
234		       struct xfrm_user_offload *xuo,
235		       struct netlink_ext_ack *extack)
236{
237	int err;
238	struct dst_entry *dst;
239	struct net_device *dev;
240	struct xfrm_dev_offload *xso = &x->xso;
241	xfrm_address_t *saddr;
242	xfrm_address_t *daddr;
243	bool is_packet_offload;
244
245	if (!x->type_offload) {
246		NL_SET_ERR_MSG(extack, "Type doesn't support offload");
247		return -EINVAL;
248	}
249
250	if (xuo->flags &
251	    ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND | XFRM_OFFLOAD_PACKET)) {
252		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
253		return -EINVAL;
254	}
255
256	is_packet_offload = xuo->flags & XFRM_OFFLOAD_PACKET;
257
258	/* We don't yet support UDP encapsulation and TFC padding. */
259	if ((!is_packet_offload && x->encap) || x->tfcpad) {
260		NL_SET_ERR_MSG(extack, "Encapsulation and TFC padding can't be offloaded");
261		return -EINVAL;
262	}
263
264	dev = dev_get_by_index(net, xuo->ifindex);
265	if (!dev) {
266		if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
267			saddr = &x->props.saddr;
268			daddr = &x->id.daddr;
269		} else {
270			saddr = &x->id.daddr;
271			daddr = &x->props.saddr;
272		}
273
274		dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
275					x->props.family,
276					xfrm_smark_get(0, x));
277		if (IS_ERR(dst))
278			return (is_packet_offload) ? -EINVAL : 0;
279
280		dev = dst->dev;
281
282		dev_hold(dev);
283		dst_release(dst);
284	}
285
286	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
287		xso->dev = NULL;
288		dev_put(dev);
289		return (is_packet_offload) ? -EINVAL : 0;
290	}
291
292	if (!is_packet_offload && x->props.flags & XFRM_STATE_ESN &&
293	    !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
294		NL_SET_ERR_MSG(extack, "Device doesn't support offload with ESN");
295		xso->dev = NULL;
296		dev_put(dev);
297		return -EINVAL;
298	}
299
300	xso->dev = dev;
301	netdev_tracker_alloc(dev, &xso->dev_tracker, GFP_ATOMIC);
302	xso->real_dev = dev;
303
304	if (xuo->flags & XFRM_OFFLOAD_INBOUND)
305		xso->dir = XFRM_DEV_OFFLOAD_IN;
306	else
307		xso->dir = XFRM_DEV_OFFLOAD_OUT;
308
309	if (is_packet_offload)
310		xso->type = XFRM_DEV_OFFLOAD_PACKET;
311	else
312		xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
313
314	err = dev->xfrmdev_ops->xdo_dev_state_add(x, extack);
315	if (err) {
316		xso->dev = NULL;
317		xso->dir = 0;
318		xso->real_dev = NULL;
319		netdev_put(dev, &xso->dev_tracker);
320		xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
321
322		/* User explicitly requested packet offload mode and configured
323		 * policy in addition to the XFRM state. So be civil to users,
324		 * and return an error instead of taking fallback path.
325		 *
326		 * This WARN_ON() can be seen as a documentation for driver
327		 * authors to do not return -EOPNOTSUPP in packet offload mode.
328		 */
329		WARN_ON(err == -EOPNOTSUPP && is_packet_offload);
330		if (err != -EOPNOTSUPP || is_packet_offload) {
331			NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this state");
332			return err;
333		}
334	}
335
336	return 0;
337}
338EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
339
340int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
341			struct xfrm_user_offload *xuo, u8 dir,
342			struct netlink_ext_ack *extack)
343{
344	struct xfrm_dev_offload *xdo = &xp->xdo;
345	struct net_device *dev;
346	int err;
347
348	if (!xuo->flags || xuo->flags & ~XFRM_OFFLOAD_PACKET) {
349		/* We support only packet offload mode and it means
350		 * that user must set XFRM_OFFLOAD_PACKET bit.
351		 */
352		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
353		return -EINVAL;
354	}
355
356	dev = dev_get_by_index(net, xuo->ifindex);
357	if (!dev)
358		return -EINVAL;
359
360	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_policy_add) {
361		xdo->dev = NULL;
362		dev_put(dev);
363		NL_SET_ERR_MSG(extack, "Policy offload is not supported");
364		return -EINVAL;
365	}
366
367	xdo->dev = dev;
368	netdev_tracker_alloc(dev, &xdo->dev_tracker, GFP_ATOMIC);
369	xdo->real_dev = dev;
370	xdo->type = XFRM_DEV_OFFLOAD_PACKET;
371	switch (dir) {
372	case XFRM_POLICY_IN:
373		xdo->dir = XFRM_DEV_OFFLOAD_IN;
374		break;
375	case XFRM_POLICY_OUT:
376		xdo->dir = XFRM_DEV_OFFLOAD_OUT;
377		break;
378	case XFRM_POLICY_FWD:
379		xdo->dir = XFRM_DEV_OFFLOAD_FWD;
380		break;
381	default:
382		xdo->dev = NULL;
383		netdev_put(dev, &xdo->dev_tracker);
384		NL_SET_ERR_MSG(extack, "Unrecognized offload direction");
385		return -EINVAL;
386	}
387
388	err = dev->xfrmdev_ops->xdo_dev_policy_add(xp, extack);
389	if (err) {
390		xdo->dev = NULL;
391		xdo->real_dev = NULL;
392		xdo->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
393		xdo->dir = 0;
394		netdev_put(dev, &xdo->dev_tracker);
395		NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this policy");
396		return err;
397	}
398
399	return 0;
400}
401EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
402
403bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
404{
405	int mtu;
406	struct dst_entry *dst = skb_dst(skb);
407	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
408	struct net_device *dev = x->xso.dev;
409
410	if (!x->type_offload ||
411	    (x->xso.type == XFRM_DEV_OFFLOAD_UNSPECIFIED && x->encap))
412		return false;
413
414	if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET ||
415	    ((!dev || (dev == xfrm_dst_path(dst)->dev)) &&
416	     !xdst->child->xfrm)) {
417		mtu = xfrm_state_mtu(x, xdst->child_mtu_cached);
418		if (skb->len <= mtu)
419			goto ok;
420
421		if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
422			goto ok;
423	}
424
425	return false;
426
427ok:
428	if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
429		return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
430
431	return true;
432}
433EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
434
435void xfrm_dev_resume(struct sk_buff *skb)
436{
437	struct net_device *dev = skb->dev;
438	int ret = NETDEV_TX_BUSY;
439	struct netdev_queue *txq;
440	struct softnet_data *sd;
441	unsigned long flags;
442
443	rcu_read_lock();
444	txq = netdev_core_pick_tx(dev, skb, NULL);
445
446	HARD_TX_LOCK(dev, txq, smp_processor_id());
447	if (!netif_xmit_frozen_or_stopped(txq))
448		skb = dev_hard_start_xmit(skb, dev, txq, &ret);
449	HARD_TX_UNLOCK(dev, txq);
450
451	if (!dev_xmit_complete(ret)) {
452		local_irq_save(flags);
453		sd = this_cpu_ptr(&softnet_data);
454		skb_queue_tail(&sd->xfrm_backlog, skb);
455		raise_softirq_irqoff(NET_TX_SOFTIRQ);
456		local_irq_restore(flags);
457	}
458	rcu_read_unlock();
459}
460EXPORT_SYMBOL_GPL(xfrm_dev_resume);
461
462void xfrm_dev_backlog(struct softnet_data *sd)
463{
464	struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
465	struct sk_buff_head list;
466	struct sk_buff *skb;
467
468	if (skb_queue_empty(xfrm_backlog))
469		return;
470
471	__skb_queue_head_init(&list);
472
473	spin_lock(&xfrm_backlog->lock);
474	skb_queue_splice_init(xfrm_backlog, &list);
475	spin_unlock(&xfrm_backlog->lock);
476
477	while (!skb_queue_empty(&list)) {
478		skb = __skb_dequeue(&list);
479		xfrm_dev_resume(skb);
480	}
481
482}
483#endif
484
485static int xfrm_api_check(struct net_device *dev)
486{
487#ifdef CONFIG_XFRM_OFFLOAD
488	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
489	    !(dev->features & NETIF_F_HW_ESP))
490		return NOTIFY_BAD;
491
492	if ((dev->features & NETIF_F_HW_ESP) &&
493	    (!(dev->xfrmdev_ops &&
494	       dev->xfrmdev_ops->xdo_dev_state_add &&
495	       dev->xfrmdev_ops->xdo_dev_state_delete)))
496		return NOTIFY_BAD;
497#else
498	if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
499		return NOTIFY_BAD;
500#endif
501
502	return NOTIFY_DONE;
503}
504
505static int xfrm_dev_down(struct net_device *dev)
506{
507	if (dev->features & NETIF_F_HW_ESP) {
508		xfrm_dev_state_flush(dev_net(dev), dev, true);
509		xfrm_dev_policy_flush(dev_net(dev), dev, true);
510	}
511
512	return NOTIFY_DONE;
513}
514
515static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
516{
517	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
518
519	switch (event) {
520	case NETDEV_REGISTER:
521		return xfrm_api_check(dev);
522
523	case NETDEV_FEAT_CHANGE:
524		return xfrm_api_check(dev);
525
526	case NETDEV_DOWN:
527	case NETDEV_UNREGISTER:
528		return xfrm_dev_down(dev);
529	}
530	return NOTIFY_DONE;
531}
532
533static struct notifier_block xfrm_dev_notifier = {
534	.notifier_call	= xfrm_dev_event,
535};
536
537void __init xfrm_dev_init(void)
538{
539	register_netdevice_notifier(&xfrm_dev_notifier);
540}
541