net/ipv6/xfrm6_output.c

   1 /*
   2  * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
   3  * Copyright (C) 2002 USAGI/WIDE Project
   4  * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/compiler.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/icmpv6.h>
  16 #include <linux/netfilter_ipv6.h>
  17 #include <net/ipv6.h>
  18 #include <net/xfrm.h>
  19
  20 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
  21                           u8 **prevhdr)
  22 {
  23         return ip6_find_1stfragopt(skb, prevhdr);
  24 }
  25
  26 EXPORT_SYMBOL(xfrm6_find_1stfragopt);
  27
  28 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
  29 {
  30         int mtu, ret = 0;
  31         struct dst_entry *dst = skb->dst;
  32
  33         mtu = dst_mtu(dst);
  34         if (mtu < IPV6_MIN_MTU)
  35                 mtu = IPV6_MIN_MTU;
  36
  37         if (skb->len > mtu) {
  38                 skb->dev = dst->dev;
  39                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
  40                 ret = -EMSGSIZE;
  41         }
  42
  43         return ret;
  44 }
  45
  46 static int xfrm6_output_one(struct sk_buff *skb)
  47 {
  48         struct dst_entry *dst = skb->dst;
  49         struct xfrm_state *x = dst->xfrm;
  50         int err;
  51
  52         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  53                 err = skb_checksum_help(skb);
  54                 if (err)
  55                         goto error_nolock;
  56         }
  57
  58         if (x->props.mode == XFRM_MODE_TUNNEL) {
  59                 err = xfrm6_tunnel_check_size(skb);
  60                 if (err)
  61                         goto error_nolock;
  62         }
  63
  64         do {
  65                 spin_lock_bh(&x->lock);
  66                 err = xfrm_state_check(x, skb);
  67                 if (err)
  68                         goto error;
  69
  70                 err = x->mode->output(x, skb);
  71                 if (err)
  72                         goto error;
  73
  74                 err = x->type->output(x, skb);
  75                 if (err)
  76                         goto error;
  77
  78                 x->curlft.bytes += skb->len;
  79                 x->curlft.packets++;
  80                 if (x->props.mode == XFRM_MODE_ROUTEOPTIMIZATION)
  81                         x->lastused = get_seconds();
  82
  83                 spin_unlock_bh(&x->lock);
  84
  85                 skb_reset_network_header(skb);
  86
  87                 if (!(skb->dst = dst_pop(dst))) {
  88                         err = -EHOSTUNREACH;
  89                         goto error_nolock;
  90                 }
  91                 dst = skb->dst;
  92                 x = dst->xfrm;
  93         } while (x && (x->props.mode != XFRM_MODE_TUNNEL));
  94
  95         IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
  96         err = 0;
  97
  98 out_exit:
  99         return err;
 100 error:
 101         spin_unlock_bh(&x->lock);
 102 error_nolock:
 103         kfree_skb(skb);
 104         goto out_exit;
 105 }
 106
 107 static int xfrm6_output_finish2(struct sk_buff *skb)
 108 {
 109         int err;
 110
 111         while (likely((err = xfrm6_output_one(skb)) == 0)) {
 112                 nf_reset(skb);
 113
 114                 err = nf_hook(PF_INET6, NF_IP6_LOCAL_OUT, &skb, NULL,
 115                               skb->dst->dev, dst_output);
 116                 if (unlikely(err != 1))
 117                         break;
 118
 119                 if (!skb->dst->xfrm)
 120                         return dst_output(skb);
 121
 122                 err = nf_hook(PF_INET6, NF_IP6_POST_ROUTING, &skb, NULL,
 123                               skb->dst->dev, xfrm6_output_finish2);
 124                 if (unlikely(err != 1))
 125                         break;
 126         }
 127
 128         return err;
 129 }
 130
 131 static int xfrm6_output_finish(struct sk_buff *skb)
 132 {
 133         struct sk_buff *segs;
 134
 135         if (!skb_is_gso(skb))
 136                 return xfrm6_output_finish2(skb);
 137
 138         skb->protocol = htons(ETH_P_IPV6);
 139         segs = skb_gso_segment(skb, 0);
 140         kfree_skb(skb);
 141         if (unlikely(IS_ERR(segs)))
 142                 return PTR_ERR(segs);
 143
 144         do {
 145                 struct sk_buff *nskb = segs->next;
 146                 int err;
 147
 148                 segs->next = NULL;
 149                 err = xfrm6_output_finish2(segs);
 150
 151                 if (unlikely(err)) {
 152                         while ((segs = nskb)) {
 153                                 nskb = segs->next;
 154                                 segs->next = NULL;
 155                                 kfree_skb(segs);
 156                         }
 157                         return err;
 158                 }
 159
 160                 segs = nskb;
 161         } while (segs);
 162
 163         return 0;
 164 }
 165
 166 int xfrm6_output(struct sk_buff *skb)
 167 {
 168         return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dst->dev,
 169                        xfrm6_output_finish);
 170 }