xfrm_device.c

  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,
 46		  skb->mac_len + x->props.header_len - x->props.enc_hdr_len);
 47}
 48
 49static void __xfrm_mode_beet_prep(struct xfrm_state *x, struct sk_buff *skb,
 50				  unsigned int hsize)
 51{
 52	struct xfrm_offload *xo = xfrm_offload(skb);
 53	int phlen = 0;
 54
 55	if (xo->flags & XFRM_GSO_SEGMENT)
 56		skb->transport_header = skb->network_header + hsize;
 57
 58	skb_reset_mac_len(skb);
 59	if (x->sel.family != AF_INET6) {
 60		phlen = IPV4_BEET_PHMAXLEN;
 61		if (x->outer_mode.family == AF_INET6)
 62			phlen += sizeof(struct ipv6hdr) - sizeof(struct iphdr);
 63	}
 64
 65	pskb_pull(skb, skb->mac_len + hsize + (x->props.header_len - phlen));
 66}
 67
 68/* Adjust pointers into the packet when IPsec is done at layer2 */
 69static void xfrm_outer_mode_prep(struct xfrm_state *x, struct sk_buff *skb)
 70{
 71	switch (x->outer_mode.encap) {
 72	case XFRM_MODE_IPTFS:
 73	case XFRM_MODE_TUNNEL:
 74		if (x->outer_mode.family == AF_INET)
 75			return __xfrm_mode_tunnel_prep(x, skb,
 76						       sizeof(struct iphdr));
 77		if (x->outer_mode.family == AF_INET6)
 78			return __xfrm_mode_tunnel_prep(x, skb,
 79						       sizeof(struct ipv6hdr));
 80		break;
 81	case XFRM_MODE_TRANSPORT:
 82		if (x->outer_mode.family == AF_INET)
 83			return __xfrm_transport_prep(x, skb,
 84						     sizeof(struct iphdr));
 85		if (x->outer_mode.family == AF_INET6)
 86			return __xfrm_transport_prep(x, skb,
 87						     sizeof(struct ipv6hdr));
 88		break;
 89	case XFRM_MODE_BEET:
 90		if (x->outer_mode.family == AF_INET)
 91			return __xfrm_mode_beet_prep(x, skb,
 92						     sizeof(struct iphdr));
 93		if (x->outer_mode.family == AF_INET6)
 94			return __xfrm_mode_beet_prep(x, skb,
 95						     sizeof(struct ipv6hdr));
 96		break;
 97	case XFRM_MODE_ROUTEOPTIMIZATION:
 98	case XFRM_MODE_IN_TRIGGER:
 99		break;
100	}
101}
102
103static inline bool xmit_xfrm_check_overflow(struct sk_buff *skb)
104{
105	struct xfrm_offload *xo = xfrm_offload(skb);
106	__u32 seq = xo->seq.low;
107
108	seq += skb_shinfo(skb)->gso_segs;
109	if (unlikely(seq < xo->seq.low))
110		return true;
111
112	return false;
113}
114
115struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features, bool *again)
116{
117	int err;
118	unsigned long flags;
119	struct xfrm_state *x;
120	struct softnet_data *sd;
121	struct sk_buff *skb2, *nskb, *pskb = NULL;
122	netdev_features_t esp_features = features;
123	struct xfrm_offload *xo = xfrm_offload(skb);
124	struct net_device *dev = skb->dev;
125	struct sec_path *sp;
126
127	if (!xo || (xo->flags & XFRM_XMIT))
128		return skb;
129
130	if (!(features & NETIF_F_HW_ESP))
131		esp_features = features & ~(NETIF_F_SG | NETIF_F_CSUM_MASK);
132
133	sp = skb_sec_path(skb);
134	x = sp->xvec[sp->len - 1];
135	if (xo->flags & XFRM_GRO || x->xso.dir == XFRM_DEV_OFFLOAD_IN)
136		return skb;
137
138	/* The packet was sent to HW IPsec packet offload engine,
139	 * but to wrong device. Drop the packet, so it won't skip
140	 * XFRM stack.
141	 */
142	if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET && x->xso.dev != dev) {
143		kfree_skb(skb);
144		dev_core_stats_tx_dropped_inc(dev);
145		return NULL;
146	}
147
148	local_irq_save(flags);
149	sd = this_cpu_ptr(&softnet_data);
150	err = !skb_queue_empty(&sd->xfrm_backlog);
151	local_irq_restore(flags);
152
153	if (err) {
154		*again = true;
155		return skb;
156	}
157
158	if (skb_is_gso(skb) && (unlikely(x->xso.dev != dev) ||
159				unlikely(xmit_xfrm_check_overflow(skb)))) {
160		struct sk_buff *segs;
161
162		/* Packet got rerouted, fixup features and segment it. */
163		esp_features = esp_features & ~(NETIF_F_HW_ESP | NETIF_F_GSO_ESP);
164
165		segs = skb_gso_segment(skb, esp_features);
166		if (IS_ERR(segs)) {
167			kfree_skb(skb);
168			dev_core_stats_tx_dropped_inc(dev);
169			return NULL;
170		} else {
171			consume_skb(skb);
172			skb = segs;
173		}
174	}
175
176	if (!skb->next) {
177		esp_features |= skb->dev->gso_partial_features;
178		xfrm_outer_mode_prep(x, skb);
179
180		xo->flags |= XFRM_DEV_RESUME;
181
182		err = x->type_offload->xmit(x, skb, esp_features);
183		if (err) {
184			if (err == -EINPROGRESS)
185				return NULL;
186
187			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
188			kfree_skb(skb);
189			return NULL;
190		}
191
192		skb_push(skb, skb->data - skb_mac_header(skb));
193
194		return skb;
195	}
196
197	skb_list_walk_safe(skb, skb2, nskb) {
198		esp_features |= skb->dev->gso_partial_features;
199		skb_mark_not_on_list(skb2);
200
201		xo = xfrm_offload(skb2);
202		xo->flags |= XFRM_DEV_RESUME;
203
204		xfrm_outer_mode_prep(x, skb2);
205
206		err = x->type_offload->xmit(x, skb2, esp_features);
207		if (!err) {
208			skb2->next = nskb;
209		} else if (err != -EINPROGRESS) {
210			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
211			skb2->next = nskb;
212			kfree_skb_list(skb2);
213			return NULL;
214		} else {
215			if (skb == skb2)
216				skb = nskb;
217			else
218				pskb->next = nskb;
219
220			continue;
221		}
222
223		skb_push(skb2, skb2->data - skb_mac_header(skb2));
224		pskb = skb2;
225	}
226
227	return skb;
228}
229EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
230
231int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
232		       struct xfrm_user_offload *xuo,
233		       struct netlink_ext_ack *extack)
234{
235	int err;
236	struct dst_entry *dst;
237	struct net_device *dev;
238	struct xfrm_dev_offload *xso = &x->xso;
239	xfrm_address_t *saddr;
240	xfrm_address_t *daddr;
241	bool is_packet_offload;
242
243	if (xuo->flags &
244	    ~(XFRM_OFFLOAD_IPV6 | XFRM_OFFLOAD_INBOUND | XFRM_OFFLOAD_PACKET)) {
245		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
246		return -EINVAL;
247	}
248
249	if ((xuo->flags & XFRM_OFFLOAD_INBOUND && x->dir == XFRM_SA_DIR_OUT) ||
250	    (!(xuo->flags & XFRM_OFFLOAD_INBOUND) && x->dir == XFRM_SA_DIR_IN)) {
251		NL_SET_ERR_MSG(extack, "Mismatched SA and offload direction");
252		return -EINVAL;
253	}
254
255	if (xuo->flags & XFRM_OFFLOAD_INBOUND && x->if_id) {
256		NL_SET_ERR_MSG(extack, "XFRM if_id is not supported in RX path");
257		return -EINVAL;
258	}
259
260	is_packet_offload = xuo->flags & XFRM_OFFLOAD_PACKET;
261
262	/* We don't yet support TFC padding. */
263	if (x->tfcpad) {
264		NL_SET_ERR_MSG(extack, "TFC padding can't be offloaded");
265		return -EINVAL;
266	}
267
268	dev = dev_get_by_index(net, xuo->ifindex);
269	if (!dev) {
270		struct xfrm_dst_lookup_params params;
271
272		if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
273			saddr = &x->props.saddr;
274			daddr = &x->id.daddr;
275		} else {
276			saddr = &x->id.daddr;
277			daddr = &x->props.saddr;
278		}
279
280		memset(&params, 0, sizeof(params));
281		params.net = net;
282		params.saddr = saddr;
283		params.daddr = daddr;
284		params.mark = xfrm_smark_get(0, x);
285		dst = __xfrm_dst_lookup(x->props.family, &params);
286		if (IS_ERR(dst))
287			return (is_packet_offload) ? -EINVAL : 0;
288
289		dev = dst->dev;
290
291		dev_hold(dev);
292		dst_release(dst);
293	}
294
295	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
296		xso->dev = NULL;
297		dev_put(dev);
298		return (is_packet_offload) ? -EINVAL : 0;
299	}
300
301	if (!is_packet_offload && x->props.flags & XFRM_STATE_ESN &&
302	    !dev->xfrmdev_ops->xdo_dev_state_advance_esn) {
303		NL_SET_ERR_MSG(extack, "Device doesn't support offload with ESN");
304		xso->dev = NULL;
305		dev_put(dev);
306		return -EINVAL;
307	}
308
309	if (!x->type_offload) {
310		NL_SET_ERR_MSG(extack, "Type doesn't support offload");
311		dev_put(dev);
312		return -EINVAL;
313	}
314
315	xso->dev = dev;
316	netdev_tracker_alloc(dev, &xso->dev_tracker, GFP_ATOMIC);
317
318	if (xuo->flags & XFRM_OFFLOAD_INBOUND)
319		xso->dir = XFRM_DEV_OFFLOAD_IN;
320	else
321		xso->dir = XFRM_DEV_OFFLOAD_OUT;
322
323	if (is_packet_offload)
324		xso->type = XFRM_DEV_OFFLOAD_PACKET;
325	else
326		xso->type = XFRM_DEV_OFFLOAD_CRYPTO;
327
328	err = dev->xfrmdev_ops->xdo_dev_state_add(dev, x, extack);
329	if (err) {
330		xso->dev = NULL;
331		xso->dir = 0;
332		netdev_put(dev, &xso->dev_tracker);
333		xso->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
334
335		xfrm_unset_type_offload(x);
336		/* User explicitly requested packet offload mode and configured
337		 * policy in addition to the XFRM state. So be civil to users,
338		 * and return an error instead of taking fallback path.
339		 */
340		if ((err != -EOPNOTSUPP && !is_packet_offload) || is_packet_offload) {
341			NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this state");
342			return err;
343		}
344	}
345
346	return 0;
347}
348EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
349
350int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
351			struct xfrm_user_offload *xuo, u8 dir,
352			struct netlink_ext_ack *extack)
353{
354	struct xfrm_dev_offload *xdo = &xp->xdo;
355	struct net_device *dev;
356	int err;
357
358	if (!xuo->flags || xuo->flags & ~XFRM_OFFLOAD_PACKET) {
359		/* We support only packet offload mode and it means
360		 * that user must set XFRM_OFFLOAD_PACKET bit.
361		 */
362		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
363		return -EINVAL;
364	}
365
366	dev = dev_get_by_index(net, xuo->ifindex);
367	if (!dev)
368		return -EINVAL;
369
370	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_policy_add) {
371		xdo->dev = NULL;
372		dev_put(dev);
373		NL_SET_ERR_MSG(extack, "Policy offload is not supported");
374		return -EINVAL;
375	}
376
377	xdo->dev = dev;
378	netdev_tracker_alloc(dev, &xdo->dev_tracker, GFP_ATOMIC);
379	xdo->type = XFRM_DEV_OFFLOAD_PACKET;
380	switch (dir) {
381	case XFRM_POLICY_IN:
382		xdo->dir = XFRM_DEV_OFFLOAD_IN;
383		break;
384	case XFRM_POLICY_OUT:
385		xdo->dir = XFRM_DEV_OFFLOAD_OUT;
386		break;
387	case XFRM_POLICY_FWD:
388		xdo->dir = XFRM_DEV_OFFLOAD_FWD;
389		break;
390	default:
391		xdo->dev = NULL;
392		netdev_put(dev, &xdo->dev_tracker);
393		NL_SET_ERR_MSG(extack, "Unrecognized offload direction");
394		return -EINVAL;
395	}
396
397	err = dev->xfrmdev_ops->xdo_dev_policy_add(xp, extack);
398	if (err) {
399		xdo->dev = NULL;
400		xdo->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
401		xdo->dir = 0;
402		netdev_put(dev, &xdo->dev_tracker);
403		NL_SET_ERR_MSG_WEAK(extack, "Device failed to offload this policy");
404		return err;
405	}
406
407	return 0;
408}
409EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
410
411bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
412{
413	int mtu;
414	struct dst_entry *dst = skb_dst(skb);
415	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
416	struct net_device *dev = x->xso.dev;
417	bool check_tunnel_size;
418
419	if (!x->type_offload ||
420	    (x->xso.type == XFRM_DEV_OFFLOAD_UNSPECIFIED && x->encap))
421		return false;
422
423	if ((!dev || dev == xfrm_dst_path(dst)->dev) &&
424	    !xdst->child->xfrm) {
425		mtu = xfrm_state_mtu(x, xdst->child_mtu_cached);
426		if (skb->len <= mtu)
427			goto ok;
428
429		if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
430			goto ok;
431	}
432
433	return false;
434
435ok:
436	if (!dev)
437		return true;
438
439	check_tunnel_size = x->xso.type == XFRM_DEV_OFFLOAD_PACKET &&
440			    x->props.mode == XFRM_MODE_TUNNEL;
441	switch (skb_dst(skb)->ops->family) {
442	case AF_INET:
443		/* Check for IPv4 options */
444		if (ip_hdr(skb)->ihl != 5)
445			return false;
446		if (check_tunnel_size && xfrm4_tunnel_check_size(skb))
447			return false;
448		break;
449	case AF_INET6:
450		/* Check for IPv6 extensions */
451		if (ipv6_ext_hdr(ipv6_hdr(skb)->nexthdr))
452			return false;
453		if (check_tunnel_size && xfrm6_tunnel_check_size(skb))
454			return false;
455		break;
456	default:
457		break;
458	}
459
460	if (dev->xfrmdev_ops->xdo_dev_offload_ok)
461		return dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
462
463	return true;
464}
465EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
466
467void xfrm_dev_resume(struct sk_buff *skb)
468{
469	struct net_device *dev = skb->dev;
470	int ret = NETDEV_TX_BUSY;
471	struct netdev_queue *txq;
472	struct softnet_data *sd;
473	unsigned long flags;
474
475	rcu_read_lock();
476	txq = netdev_core_pick_tx(dev, skb, NULL);
477
478	HARD_TX_LOCK(dev, txq, smp_processor_id());
479	if (!netif_xmit_frozen_or_stopped(txq))
480		skb = dev_hard_start_xmit(skb, dev, txq, &ret);
481	HARD_TX_UNLOCK(dev, txq);
482
483	if (!dev_xmit_complete(ret)) {
484		local_irq_save(flags);
485		sd = this_cpu_ptr(&softnet_data);
486		skb_queue_tail(&sd->xfrm_backlog, skb);
487		raise_softirq_irqoff(NET_TX_SOFTIRQ);
488		local_irq_restore(flags);
489	}
490	rcu_read_unlock();
491}
492EXPORT_SYMBOL_GPL(xfrm_dev_resume);
493
494void xfrm_dev_backlog(struct softnet_data *sd)
495{
496	struct sk_buff_head *xfrm_backlog = &sd->xfrm_backlog;
497	struct sk_buff_head list;
498	struct sk_buff *skb;
499
500	if (skb_queue_empty(xfrm_backlog))
501		return;
502
503	__skb_queue_head_init(&list);
504
505	spin_lock(&xfrm_backlog->lock);
506	skb_queue_splice_init(xfrm_backlog, &list);
507	spin_unlock(&xfrm_backlog->lock);
508
509	while (!skb_queue_empty(&list)) {
510		skb = __skb_dequeue(&list);
511		xfrm_dev_resume(skb);
512	}
513
514}
515#endif
516
517static int xfrm_api_check(struct net_device *dev)
518{
519#ifdef CONFIG_XFRM_OFFLOAD
520	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
521	    !(dev->features & NETIF_F_HW_ESP))
522		return NOTIFY_BAD;
523
524	if ((dev->features & NETIF_F_HW_ESP) &&
525	    (!(dev->xfrmdev_ops &&
526	       dev->xfrmdev_ops->xdo_dev_state_add &&
527	       dev->xfrmdev_ops->xdo_dev_state_delete)))
528		return NOTIFY_BAD;
529#else
530	if (dev->features & (NETIF_F_HW_ESP | NETIF_F_HW_ESP_TX_CSUM))
531		return NOTIFY_BAD;
532#endif
533
534	return NOTIFY_DONE;
535}
536
537static int xfrm_dev_down(struct net_device *dev)
538{
539	if (dev->features & NETIF_F_HW_ESP) {
540		xfrm_dev_state_flush(dev_net(dev), dev, true);
541		xfrm_dev_policy_flush(dev_net(dev), dev, true);
542	}
543
544	return NOTIFY_DONE;
545}
546
547static int xfrm_dev_unregister(struct net_device *dev)
548{
549	xfrm_dev_state_flush(dev_net(dev), dev, true);
550	xfrm_dev_policy_flush(dev_net(dev), dev, true);
551
552	return NOTIFY_DONE;
553}
554
555static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
556{
557	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
558
559	switch (event) {
560	case NETDEV_REGISTER:
561		return xfrm_api_check(dev);
562
563	case NETDEV_FEAT_CHANGE:
564		return xfrm_api_check(dev);
565
566	case NETDEV_DOWN:
567		return xfrm_dev_down(dev);
568
569	case NETDEV_UNREGISTER:
570		return xfrm_dev_unregister(dev);
571	}
572	return NOTIFY_DONE;
573}
574
575static struct notifier_block xfrm_dev_notifier = {
576	.notifier_call	= xfrm_dev_event,
577};
578
579void __init xfrm_dev_init(void)
580{
581	register_netdevice_notifier(&xfrm_dev_notifier);
582}