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 -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                 dev_put(dev);
  95                 return 0;
  96         }
  97
  98         xso->dev = dev;
  99         xso->num_exthdrs = 1;
 100         xso->flags = xuo->flags;
 101
 102         err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 103         if (err) {
 104                 dev_put(dev);
 105                 return err;
 106         }
 107
 108         return 0;
 109 }
 110 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 111
 112 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 113 {
 114         int mtu;
 115         struct dst_entry *dst = skb_dst(skb);
 116         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 117         struct net_device *dev = x->xso.dev;
 118
 119         if (!x->type_offload || x->encap)
 120                 return false;
 121
 122         if ((x->xso.offload_handle && (dev == dst->path->dev)) &&
 123              !dst->child->xfrm && x->type->get_mtu) {
 124                 mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
 125
 126                 if (skb->len <= mtu)
 127                         goto ok;
 128
 129                 if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
 130                         goto ok;
 131         }
 132
 133         return false;
 134
 135 ok:
 136         if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 137                 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
 138
 139         return true;
 140 }
 141 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 142 #endif
 143
 144 static int xfrm_dev_register(struct net_device *dev)
 145 {
 146         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 147                 return NOTIFY_BAD;
 148         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 149             !(dev->features & NETIF_F_HW_ESP))
 150                 return NOTIFY_BAD;
 151
 152         return NOTIFY_DONE;
 153 }
 154
 155 static int xfrm_dev_unregister(struct net_device *dev)
 156 {
 157         xfrm_policy_cache_flush();
 158         return NOTIFY_DONE;
 159 }
 160
 161 static int xfrm_dev_feat_change(struct net_device *dev)
 162 {
 163         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 164                 return NOTIFY_BAD;
 165         else if (!(dev->features & NETIF_F_HW_ESP))
 166                 dev->xfrmdev_ops = NULL;
 167
 168         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 169             !(dev->features & NETIF_F_HW_ESP))
 170                 return NOTIFY_BAD;
 171
 172         return NOTIFY_DONE;
 173 }
 174
 175 static int xfrm_dev_down(struct net_device *dev)
 176 {
 177         if (dev->features & NETIF_F_HW_ESP)
 178                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 179
 180         xfrm_policy_cache_flush();
 181         return NOTIFY_DONE;
 182 }
 183
 184 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 185 {
 186         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 187
 188         switch (event) {
 189         case NETDEV_REGISTER:
 190                 return xfrm_dev_register(dev);
 191
 192         case NETDEV_UNREGISTER:
 193                 return xfrm_dev_unregister(dev);
 194
 195         case NETDEV_FEAT_CHANGE:
 196                 return xfrm_dev_feat_change(dev);
 197
 198         case NETDEV_DOWN:
 199                 return xfrm_dev_down(dev);
 200         }
 201         return NOTIFY_DONE;
 202 }
 203
 204 static struct notifier_block xfrm_dev_notifier = {
 205         .notifier_call  = xfrm_dev_event,
 206 };
 207
 208 void __net_init xfrm_dev_init(void)
 209 {
 210         register_netdevice_notifier(&xfrm_dev_notifier);
 211 }