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/if_ether.h>
  13 #include <linux/compiler.h>
  14 #include <linux/skbuff.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 inline 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 (x->props.mode == XFRM_MODE_TUNNEL) {
  53                 err = xfrm6_tunnel_check_size(skb);
  54                 if (err)
  55                         goto error_nolock;
  56         }
  57
  58         err = xfrm_output(skb);
  59         if (err)
  60                 goto error_nolock;
  61
  62         IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
  63         err = 0;
  64
  65 out_exit:
  66         return err;
  67 error_nolock:
  68         kfree_skb(skb);
  69         goto out_exit;
  70 }
  71
  72 static int xfrm6_output_finish2(struct sk_buff *skb)
  73 {
  74         int err;
  75
  76         while (likely((err = xfrm6_output_one(skb)) == 0)) {
  77                 nf_reset(skb);
  78
  79                 err = nf_hook(PF_INET6, NF_IP6_LOCAL_OUT, &skb, NULL,
  80                               skb->dst->dev, dst_output);
  81                 if (unlikely(err != 1))
  82                         break;
  83
  84                 if (!skb->dst->xfrm)
  85                         return dst_output(skb);
  86
  87                 err = nf_hook(PF_INET6, NF_IP6_POST_ROUTING, &skb, NULL,
  88                               skb->dst->dev, xfrm6_output_finish2);
  89                 if (unlikely(err != 1))
  90                         break;
  91         }
  92
  93         return err;
  94 }
  95
  96 static int xfrm6_output_finish(struct sk_buff *skb)
  97 {
  98         struct sk_buff *segs;
  99
 100         if (!skb_is_gso(skb))
 101                 return xfrm6_output_finish2(skb);
 102
 103         skb->protocol = htons(ETH_P_IPV6);
 104         segs = skb_gso_segment(skb, 0);
 105         kfree_skb(skb);
 106         if (unlikely(IS_ERR(segs)))
 107                 return PTR_ERR(segs);
 108
 109         do {
 110                 struct sk_buff *nskb = segs->next;
 111                 int err;
 112
 113                 segs->next = NULL;
 114                 err = xfrm6_output_finish2(segs);
 115
 116                 if (unlikely(err)) {
 117                         while ((segs = nskb)) {
 118                                 nskb = segs->next;
 119                                 segs->next = NULL;
 120                                 kfree_skb(segs);
 121                         }
 122                         return err;
 123                 }
 124
 125                 segs = nskb;
 126         } while (segs);
 127
 128         return 0;
 129 }
 130
 131 int xfrm6_output(struct sk_buff *skb)
 132 {
 133         return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dst->dev,
 134                        xfrm6_output_finish);
 135 }