net/xfrm/xfrm_device.c

   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 0;
  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, x->props.family);
  83                 if (IS_ERR(dst))
  84                         return 0;
  85
  86                 dev = dst->dev;
  87
  88                 dev_hold(dev);
  89                 dst_release(dst);
  90         }
  91
  92         if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
  93                 dev_put(dev);
  94                 return 0;
  95         }
  96
  97         xso->dev = dev;
  98         xso->num_exthdrs = 1;
  99         xso->flags = xuo->flags;
 100
 101         err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 102         if (err) {
 103                 dev_put(dev);
 104                 return err;
 105         }
 106
 107         return 0;
 108 }
 109 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 110
 111 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 112 {
 113         int mtu;
 114         struct dst_entry *dst = skb_dst(skb);
 115         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 116         struct net_device *dev = x->xso.dev;
 117
 118         if (!x->type_offload || x->encap)
 119                 return false;
 120
 121         if ((x->xso.offload_handle && (dev == dst->path->dev)) &&
 122              !dst->child->xfrm && x->type->get_mtu) {
 123                 mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
 124
 125                 if (skb->len <= mtu)
 126                         goto ok;
 127
 128                 if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
 129                         goto ok;
 130         }
 131
 132         return false;
 133
 134 ok:
 135         if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 136                 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
 137
 138         return true;
 139 }
 140 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 141 #endif
 142
 143 static int xfrm_dev_register(struct net_device *dev)
 144 {
 145         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 146                 return NOTIFY_BAD;
 147         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 148             !(dev->features & NETIF_F_HW_ESP))
 149                 return NOTIFY_BAD;
 150
 151         return NOTIFY_DONE;
 152 }
 153
 154 static int xfrm_dev_unregister(struct net_device *dev)
 155 {
 156         return NOTIFY_DONE;
 157 }
 158
 159 static int xfrm_dev_feat_change(struct net_device *dev)
 160 {
 161         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 162                 return NOTIFY_BAD;
 163         else if (!(dev->features & NETIF_F_HW_ESP))
 164                 dev->xfrmdev_ops = NULL;
 165
 166         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 167             !(dev->features & NETIF_F_HW_ESP))
 168                 return NOTIFY_BAD;
 169
 170         return NOTIFY_DONE;
 171 }
 172
 173 static int xfrm_dev_down(struct net_device *dev)
 174 {
 175         if (dev->features & NETIF_F_HW_ESP)
 176                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 177
 178         xfrm_garbage_collect(dev_net(dev));
 179
 180         return NOTIFY_DONE;
 181 }
 182
 183 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 184 {
 185         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 186
 187         switch (event) {
 188         case NETDEV_REGISTER:
 189                 return xfrm_dev_register(dev);
 190
 191         case NETDEV_UNREGISTER:
 192                 return xfrm_dev_unregister(dev);
 193
 194         case NETDEV_FEAT_CHANGE:
 195                 return xfrm_dev_feat_change(dev);
 196
 197         case NETDEV_DOWN:
 198                 return xfrm_dev_down(dev);
 199         }
 200         return NOTIFY_DONE;
 201 }
 202
 203 static struct notifier_block xfrm_dev_notifier = {
 204         .notifier_call  = xfrm_dev_event,
 205 };
 206
 207 void __net_init xfrm_dev_init(void)
 208 {
 209         register_netdevice_notifier(&xfrm_dev_notifier);
 210 }