f21596f89984ed6952d4e4dfaa62ab19c74e97e0
[linux-2.6.git] / 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 }