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                 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 }