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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * xfrm4_output.c - Common IPsec encapsulation code for IPv4. | |
3 | * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | */ | |
10 | ||
16a6677f | 11 | #include <linux/compiler.h> |
1da177e4 LT |
12 | #include <linux/skbuff.h> |
13 | #include <linux/spinlock.h> | |
16a6677f | 14 | #include <linux/netfilter_ipv4.h> |
1da177e4 LT |
15 | #include <net/ip.h> |
16 | #include <net/xfrm.h> | |
17 | #include <net/icmp.h> | |
18 | ||
1da177e4 LT |
19 | static int xfrm4_tunnel_check_size(struct sk_buff *skb) |
20 | { | |
21 | int mtu, ret = 0; | |
22 | struct dst_entry *dst; | |
23 | struct iphdr *iph = skb->nh.iph; | |
24 | ||
25 | if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) | |
26 | goto out; | |
27 | ||
28 | IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; | |
29 | ||
30 | if (!(iph->frag_off & htons(IP_DF)) || skb->local_df) | |
31 | goto out; | |
32 | ||
33 | dst = skb->dst; | |
34 | mtu = dst_mtu(dst); | |
35 | if (skb->len > mtu) { | |
36 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); | |
37 | ret = -EMSGSIZE; | |
38 | } | |
39 | out: | |
40 | return ret; | |
41 | } | |
42 | ||
16a6677f | 43 | static int xfrm4_output_one(struct sk_buff *skb) |
1da177e4 LT |
44 | { |
45 | struct dst_entry *dst = skb->dst; | |
46 | struct xfrm_state *x = dst->xfrm; | |
47 | int err; | |
48 | ||
49 | if (skb->ip_summed == CHECKSUM_HW) { | |
50 | err = skb_checksum_help(skb, 0); | |
51 | if (err) | |
52 | goto error_nolock; | |
53 | } | |
54 | ||
55 | if (x->props.mode) { | |
56 | err = xfrm4_tunnel_check_size(skb); | |
57 | if (err) | |
58 | goto error_nolock; | |
59 | } | |
60 | ||
16a6677f PM |
61 | do { |
62 | spin_lock_bh(&x->lock); | |
63 | err = xfrm_state_check(x, skb); | |
64 | if (err) | |
65 | goto error; | |
1da177e4 | 66 | |
b59f45d0 HX |
67 | err = x->mode->output(skb); |
68 | if (err) | |
69 | goto error; | |
1da177e4 | 70 | |
16a6677f PM |
71 | err = x->type->output(x, skb); |
72 | if (err) | |
73 | goto error; | |
1da177e4 | 74 | |
16a6677f PM |
75 | x->curlft.bytes += skb->len; |
76 | x->curlft.packets++; | |
1da177e4 | 77 | |
16a6677f | 78 | spin_unlock_bh(&x->lock); |
1da177e4 | 79 | |
16a6677f PM |
80 | if (!(skb->dst = dst_pop(dst))) { |
81 | err = -EHOSTUNREACH; | |
82 | goto error_nolock; | |
83 | } | |
84 | dst = skb->dst; | |
85 | x = dst->xfrm; | |
86 | } while (x && !x->props.mode); | |
87 | ||
3e3850e9 | 88 | IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; |
16a6677f | 89 | err = 0; |
1da177e4 LT |
90 | |
91 | out_exit: | |
92 | return err; | |
93 | error: | |
94 | spin_unlock_bh(&x->lock); | |
95 | error_nolock: | |
96 | kfree_skb(skb); | |
97 | goto out_exit; | |
98 | } | |
16a6677f | 99 | |
48d5cad8 | 100 | static int xfrm4_output_finish(struct sk_buff *skb) |
16a6677f PM |
101 | { |
102 | int err; | |
103 | ||
48d5cad8 PM |
104 | #ifdef CONFIG_NETFILTER |
105 | if (!skb->dst->xfrm) { | |
106 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
107 | return dst_output(skb); | |
108 | } | |
109 | #endif | |
16a6677f PM |
110 | while (likely((err = xfrm4_output_one(skb)) == 0)) { |
111 | nf_reset(skb); | |
112 | ||
113 | err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL, | |
114 | skb->dst->dev, dst_output); | |
115 | if (unlikely(err != 1)) | |
116 | break; | |
117 | ||
118 | if (!skb->dst->xfrm) | |
119 | return dst_output(skb); | |
120 | ||
121 | err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL, | |
122 | skb->dst->dev, xfrm4_output_finish); | |
123 | if (unlikely(err != 1)) | |
124 | break; | |
125 | } | |
126 | ||
127 | return err; | |
128 | } | |
129 | ||
130 | int xfrm4_output(struct sk_buff *skb) | |
131 | { | |
48d5cad8 PM |
132 | return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev, |
133 | xfrm4_output_finish, | |
134 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
16a6677f | 135 | } |