xref: /openbmc/linux/net/xfrm/xfrm_device.c (revision 8ee90c5c)
1 /*
2  * xfrm_device.c - IPsec device offloading code.
3  *
4  * Copyright (c) 2015 secunet Security Networks AG
5  *
6  * Author:
7  * Steffen Klassert <steffen.klassert@secunet.com>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version
12  * 2 of the License, or (at your option) any later version.
13  */
14 
15 #include <linux/errno.h>
16 #include <linux/module.h>
17 #include <linux/netdevice.h>
18 #include <linux/skbuff.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21 #include <net/dst.h>
22 #include <net/xfrm.h>
23 #include <linux/notifier.h>
24 
25 #ifdef CONFIG_XFRM_OFFLOAD
26 int validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features)
27 {
28 	int err;
29 	struct xfrm_state *x;
30 	struct xfrm_offload *xo = xfrm_offload(skb);
31 
32 	if (skb_is_gso(skb))
33 		return 0;
34 
35 	if (xo) {
36 		x = skb->sp->xvec[skb->sp->len - 1];
37 		if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
38 			return 0;
39 
40 		x->outer_mode->xmit(x, skb);
41 
42 		err = x->type_offload->xmit(x, skb, features);
43 		if (err) {
44 			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
45 			return err;
46 		}
47 
48 		skb_push(skb, skb->data - skb_mac_header(skb));
49 	}
50 
51 	return 0;
52 }
53 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
54 
55 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
56 		       struct xfrm_user_offload *xuo)
57 {
58 	int err;
59 	struct dst_entry *dst;
60 	struct net_device *dev;
61 	struct xfrm_state_offload *xso = &x->xso;
62 	xfrm_address_t *saddr;
63 	xfrm_address_t *daddr;
64 
65 	if (!x->type_offload)
66 		return -EINVAL;
67 
68 	/* We don't yet support UDP encapsulation, TFC padding and ESN. */
69 	if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
70 		return 0;
71 
72 	dev = dev_get_by_index(net, xuo->ifindex);
73 	if (!dev) {
74 		if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
75 			saddr = &x->props.saddr;
76 			daddr = &x->id.daddr;
77 		} else {
78 			saddr = &x->id.daddr;
79 			daddr = &x->props.saddr;
80 		}
81 
82 		dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr,
83 					x->props.family, x->props.output_mark);
84 		if (IS_ERR(dst))
85 			return 0;
86 
87 		dev = dst->dev;
88 
89 		dev_hold(dev);
90 		dst_release(dst);
91 	}
92 
93 	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
94 		xso->dev = NULL;
95 		dev_put(dev);
96 		return 0;
97 	}
98 
99 	xso->dev = dev;
100 	xso->num_exthdrs = 1;
101 	xso->flags = xuo->flags;
102 
103 	err = dev->xfrmdev_ops->xdo_dev_state_add(x);
104 	if (err) {
105 		dev_put(dev);
106 		return err;
107 	}
108 
109 	return 0;
110 }
111 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
112 
113 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
114 {
115 	int mtu;
116 	struct dst_entry *dst = skb_dst(skb);
117 	struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
118 	struct net_device *dev = x->xso.dev;
119 
120 	if (!x->type_offload || x->encap)
121 		return false;
122 
123 	if ((x->xso.offload_handle && (dev == dst->path->dev)) &&
124 	     !dst->child->xfrm && x->type->get_mtu) {
125 		mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
126 
127 		if (skb->len <= mtu)
128 			goto ok;
129 
130 		if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
131 			goto ok;
132 	}
133 
134 	return false;
135 
136 ok:
137 	if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
138 		return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
139 
140 	return true;
141 }
142 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
143 #endif
144 
145 static int xfrm_dev_register(struct net_device *dev)
146 {
147 	if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
148 		return NOTIFY_BAD;
149 	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
150 	    !(dev->features & NETIF_F_HW_ESP))
151 		return NOTIFY_BAD;
152 
153 	return NOTIFY_DONE;
154 }
155 
156 static int xfrm_dev_unregister(struct net_device *dev)
157 {
158 	xfrm_policy_cache_flush();
159 	return NOTIFY_DONE;
160 }
161 
162 static int xfrm_dev_feat_change(struct net_device *dev)
163 {
164 	if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
165 		return NOTIFY_BAD;
166 	else if (!(dev->features & NETIF_F_HW_ESP))
167 		dev->xfrmdev_ops = NULL;
168 
169 	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
170 	    !(dev->features & NETIF_F_HW_ESP))
171 		return NOTIFY_BAD;
172 
173 	return NOTIFY_DONE;
174 }
175 
176 static int xfrm_dev_down(struct net_device *dev)
177 {
178 	if (dev->features & NETIF_F_HW_ESP)
179 		xfrm_dev_state_flush(dev_net(dev), dev, true);
180 
181 	xfrm_policy_cache_flush();
182 	return NOTIFY_DONE;
183 }
184 
185 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
186 {
187 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
188 
189 	switch (event) {
190 	case NETDEV_REGISTER:
191 		return xfrm_dev_register(dev);
192 
193 	case NETDEV_UNREGISTER:
194 		return xfrm_dev_unregister(dev);
195 
196 	case NETDEV_FEAT_CHANGE:
197 		return xfrm_dev_feat_change(dev);
198 
199 	case NETDEV_DOWN:
200 		return xfrm_dev_down(dev);
201 	}
202 	return NOTIFY_DONE;
203 }
204 
205 static struct notifier_block xfrm_dev_notifier = {
206 	.notifier_call	= xfrm_dev_event,
207 };
208 
209 void __net_init xfrm_dev_init(void)
210 {
211 	register_netdevice_notifier(&xfrm_dev_notifier);
212 }
213