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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
__xfrm_transport_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)23  static 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  
__xfrm_mode_tunnel_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)35  static 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  
__xfrm_mode_beet_prep(struct xfrm_state * x,struct sk_buff * skb,unsigned int hsize)48  static 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 */
xfrm_outer_mode_prep(struct xfrm_state * x,struct sk_buff * skb)68  static 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  
xmit_xfrm_check_overflow(struct sk_buff * skb)101  static 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  
validate_xmit_xfrm(struct sk_buff * skb,netdev_features_t features,bool * again)113  struct 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  }
231  EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
232  
xfrm_dev_state_add(struct net * net,struct xfrm_state * x,struct xfrm_user_offload * xuo,struct netlink_ext_ack * extack)233  int 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  }
338  EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
339  
xfrm_dev_policy_add(struct net * net,struct xfrm_policy * xp,struct xfrm_user_offload * xuo,u8 dir,struct netlink_ext_ack * extack)340  int 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  }
401  EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
402  
xfrm_dev_offload_ok(struct sk_buff * skb,struct xfrm_state * x)403  bool 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  
427  ok:
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  }
433  EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
434  
xfrm_dev_resume(struct sk_buff * skb)435  void 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  }
460  EXPORT_SYMBOL_GPL(xfrm_dev_resume);
461  
xfrm_dev_backlog(struct softnet_data * sd)462  void 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  
xfrm_api_check(struct net_device * dev)485  static 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  
xfrm_dev_down(struct net_device * dev)505  static 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  
xfrm_dev_event(struct notifier_block * this,unsigned long event,void * ptr)515  static 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  
533  static struct notifier_block xfrm_dev_notifier = {
534  	.notifier_call	= xfrm_dev_event,
535  };
536  
xfrm_dev_init(void)537  void __init xfrm_dev_init(void)
538  {
539  	register_netdevice_notifier(&xfrm_dev_notifier);
540  }
541