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 int validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t features)
  26 {
  27         int err;
  28         struct xfrm_state *x;
  29         struct xfrm_offload *xo = xfrm_offload(skb);
  30
  31         if (skb_is_gso(skb))
  32                 return 0;
  33
  34         if (xo) {
  35                 x = skb->sp->xvec[skb->sp->len - 1];
  36                 if (xo->flags & XFRM_GRO || x->xso.flags & XFRM_OFFLOAD_INBOUND)
  37                         return 0;
  38
  39                 x->outer_mode->xmit(x, skb);
  40
  41                 err = x->type_offload->xmit(x, skb, features);
  42                 if (err) {
  43                         XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
  44                         return err;
  45                 }
  46
  47                 skb_push(skb, skb->data - skb_mac_header(skb));
  48         }
  49
  50         return 0;
  51 }
  52 EXPORT_SYMBOL_GPL(validate_xmit_xfrm);
  53
  54 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
  55                        struct xfrm_user_offload *xuo)
  56 {
  57         int err;
  58         struct dst_entry *dst;
  59         struct net_device *dev;
  60         struct xfrm_state_offload *xso = &x->xso;
  61         xfrm_address_t *saddr;
  62         xfrm_address_t *daddr;
  63
  64         if (!x->type_offload)
  65                 return 0;
  66
  67         /* We don't yet support UDP encapsulation, TFC padding and ESN. */
  68         if (x->encap || x->tfcpad || (x->props.flags & XFRM_STATE_ESN))
  69                 return 0;
  70
  71         dev = dev_get_by_index(net, xuo->ifindex);
  72         if (!dev) {
  73                 if (!(xuo->flags & XFRM_OFFLOAD_INBOUND)) {
  74                         saddr = &x->props.saddr;
  75                         daddr = &x->id.daddr;
  76                 } else {
  77                         saddr = &x->id.daddr;
  78                         daddr = &x->props.saddr;
  79                 }
  80
  81                 dst = __xfrm_dst_lookup(net, 0, 0, saddr, daddr, x->props.family);
  82                 if (IS_ERR(dst))
  83                         return 0;
  84
  85                 dev = dst->dev;
  86
  87                 dev_hold(dev);
  88                 dst_release(dst);
  89         }
  90
  91         if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_state_add) {
  92                 dev_put(dev);
  93                 return 0;
  94         }
  95
  96         xso->dev = dev;
  97         xso->num_exthdrs = 1;
  98         xso->flags = xuo->flags;
  99
 100         err = dev->xfrmdev_ops->xdo_dev_state_add(x);
 101         if (err) {
 102                 dev_put(dev);
 103                 return err;
 104         }
 105
 106         return 0;
 107 }
 108 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 109
 110 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 111 {
 112         int mtu;
 113         struct dst_entry *dst = skb_dst(skb);
 114         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 115         struct net_device *dev = x->xso.dev;
 116
 117         if (!x->type_offload || x->encap)
 118                 return false;
 119
 120         if ((x->xso.offload_handle && (dev == dst->path->dev)) &&
 121              !dst->child->xfrm && x->type->get_mtu) {
 122                 mtu = x->type->get_mtu(x, xdst->child_mtu_cached);
 123
 124                 if (skb->len <= mtu)
 125                         goto ok;
 126
 127                 if (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
 128                         goto ok;
 129         }
 130
 131         return false;
 132
 133 ok:
 134         if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_offload_ok)
 135                 return x->xso.dev->xfrmdev_ops->xdo_dev_offload_ok(skb, x);
 136
 137         return true;
 138 }
 139 EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 140
 141 int xfrm_dev_register(struct net_device *dev)
 142 {
 143         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 144                 return NOTIFY_BAD;
 145         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 146             !(dev->features & NETIF_F_HW_ESP))
 147                 return NOTIFY_BAD;
 148
 149         return NOTIFY_DONE;
 150 }
 151
 152 static int xfrm_dev_unregister(struct net_device *dev)
 153 {
 154         return NOTIFY_DONE;
 155 }
 156
 157 static int xfrm_dev_feat_change(struct net_device *dev)
 158 {
 159         if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
 160                 return NOTIFY_BAD;
 161         else if (!(dev->features & NETIF_F_HW_ESP))
 162                 dev->xfrmdev_ops = NULL;
 163
 164         if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
 165             !(dev->features & NETIF_F_HW_ESP))
 166                 return NOTIFY_BAD;
 167
 168         return NOTIFY_DONE;
 169 }
 170
 171 static int xfrm_dev_down(struct net_device *dev)
 172 {
 173         if (dev->hw_features & NETIF_F_HW_ESP)
 174                 xfrm_dev_state_flush(dev_net(dev), dev, true);
 175
 176         xfrm_garbage_collect(dev_net(dev));
 177
 178         return NOTIFY_DONE;
 179 }
 180
 181 static int xfrm_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
 182 {
 183         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 184
 185         switch (event) {
 186         case NETDEV_REGISTER:
 187                 return xfrm_dev_register(dev);
 188
 189         case NETDEV_UNREGISTER:
 190                 return xfrm_dev_unregister(dev);
 191
 192         case NETDEV_FEAT_CHANGE:
 193                 return xfrm_dev_feat_change(dev);
 194
 195         case NETDEV_DOWN:
 196                 return xfrm_dev_down(dev);
 197         }
 198         return NOTIFY_DONE;
 199 }
 200
 201 static struct notifier_block xfrm_dev_notifier = {
 202         .notifier_call  = xfrm_dev_event,
 203 };
 204
 205 void __net_init xfrm_dev_init(void)
 206 {
 207         register_netdevice_notifier(&xfrm_dev_notifier);
 208 }