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 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
  27 {
  28         int mtu, ret = 0;
  29         struct dst_entry *dst = skb->dst;
  30
  31         mtu = dst_mtu(dst);
  32         if (mtu < IPV6_MIN_MTU)
  33                 mtu = IPV6_MIN_MTU;
  34
  35         if (skb->len > mtu) {
  36                 skb->dev = dst->dev;
  37                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
  38                 ret = -EMSGSIZE;
  39         }
  40
  41         return ret;
  42 }
  43
  44 static int xfrm6_output_one(struct sk_buff *skb)
  45 {
  46         struct dst_entry *dst = skb->dst;
  47         struct xfrm_state *x = dst->xfrm;
  48         int err;
  49
  50         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  51                 err = skb_checksum_help(skb);
  52                 if (err)
  53                         goto error_nolock;
  54         }
  55
  56         if (x->props.mode == XFRM_MODE_TUNNEL) {
  57                 err = xfrm6_tunnel_check_size(skb);
  58                 if (err)
  59                         goto error_nolock;
  60         }
  61
  62         do {
  63                 spin_lock_bh(&x->lock);
  64                 err = xfrm_state_check(x, skb);
  65                 if (err)
  66                         goto error;
  67
  68                 err = x->mode->output(skb);
  69                 if (err)
  70                         goto error;
  71
  72                 err = x->type->output(x, skb);
  73                 if (err)
  74                         goto error;
  75
  76                 x->curlft.bytes += skb->len;
  77                 x->curlft.packets++;
  78
  79                 spin_unlock_bh(&x->lock);
  80
  81                 skb->nh.raw = skb->data;
  82
  83                 if (!(skb->dst = dst_pop(dst))) {
  84                         err = -EHOSTUNREACH;
  85                         goto error_nolock;
  86                 }
  87                 dst = skb->dst;
  88                 x = dst->xfrm;
  89         } while (x && (x->props.mode != XFRM_MODE_TUNNEL));
  90
  91         IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
  92         err = 0;
  93
  94 out_exit:
  95         return err;
  96 error:
  97         spin_unlock_bh(&x->lock);
  98 error_nolock:
  99         kfree_skb(skb);
 100         goto out_exit;
 101 }
 102
 103 static int xfrm6_output_finish2(struct sk_buff *skb)
 104 {
 105         int err;
 106
 107         while (likely((err = xfrm6_output_one(skb)) == 0)) {
 108                 nf_reset(skb);
 109
 110                 err = nf_hook(PF_INET6, NF_IP6_LOCAL_OUT, &skb, NULL,
 111                               skb->dst->dev, dst_output);
 112                 if (unlikely(err != 1))
 113                         break;
 114
 115                 if (!skb->dst->xfrm)
 116                         return dst_output(skb);
 117
 118                 err = nf_hook(PF_INET6, NF_IP6_POST_ROUTING, &skb, NULL,
 119                               skb->dst->dev, xfrm6_output_finish2);
 120                 if (unlikely(err != 1))
 121                         break;
 122         }
 123
 124         return err;
 125 }
 126
 127 static int xfrm6_output_finish(struct sk_buff *skb)
 128 {
 129         struct sk_buff *segs;
 130
 131         if (!skb_is_gso(skb))
 132                 return xfrm6_output_finish2(skb);
 133
 134         skb->protocol = htons(ETH_P_IPV6);
 135         segs = skb_gso_segment(skb, 0);
 136         kfree_skb(skb);
 137         if (unlikely(IS_ERR(segs)))
 138                 return PTR_ERR(segs);
 139
 140         do {
 141                 struct sk_buff *nskb = segs->next;
 142                 int err;
 143
 144                 segs->next = NULL;
 145                 err = xfrm6_output_finish2(segs);
 146
 147                 if (unlikely(err)) {
 148                         while ((segs = nskb)) {
 149                                 nskb = segs->next;
 150                                 segs->next = NULL;
 151                                 kfree_skb(segs);
 152                         }
 153                         return err;
 154                 }
 155
 156                 segs = nskb;
 157         } while (segs);
 158
 159         return 0;
 160 }
 161
 162 int xfrm6_output(struct sk_buff *skb)
 163 {
 164         return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dst->dev,
 165                        xfrm6_output_finish);
 166 }