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> | |
e905a9ed | 4 | * |
1da177e4 LT |
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 | ||
09b8f7a9 HX |
11 | #include <linux/if_ether.h> |
12 | #include <linux/kernel.h> | |
36cf9acf | 13 | #include <linux/module.h> |
1da177e4 | 14 | #include <linux/skbuff.h> |
16a6677f | 15 | #include <linux/netfilter_ipv4.h> |
36cf9acf | 16 | #include <net/dst.h> |
1da177e4 LT |
17 | #include <net/ip.h> |
18 | #include <net/xfrm.h> | |
19 | #include <net/icmp.h> | |
20 | ||
1da177e4 LT |
21 | static int xfrm4_tunnel_check_size(struct sk_buff *skb) |
22 | { | |
23 | int mtu, ret = 0; | |
1da177e4 LT |
24 | |
25 | if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) | |
26 | goto out; | |
27 | ||
60ff7467 | 28 | if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df) |
1da177e4 LT |
29 | goto out; |
30 | ||
5a25cf1e | 31 | mtu = dst_mtu(skb_dst(skb)); |
1da177e4 | 32 | if (skb->len > mtu) { |
b00897b8 | 33 | if (skb->sk) |
628e341f | 34 | xfrm_local_error(skb, mtu); |
b00897b8 SK |
35 | else |
36 | icmp_send(skb, ICMP_DEST_UNREACH, | |
37 | ICMP_FRAG_NEEDED, htonl(mtu)); | |
1da177e4 LT |
38 | ret = -EMSGSIZE; |
39 | } | |
40 | out: | |
41 | return ret; | |
42 | } | |
43 | ||
36cf9acf HX |
44 | int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb) |
45 | { | |
46 | int err; | |
47 | ||
48 | err = xfrm4_tunnel_check_size(skb); | |
49 | if (err) | |
50 | return err; | |
51 | ||
60d5fcfb HX |
52 | XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol; |
53 | ||
36cf9acf HX |
54 | return xfrm4_extract_header(skb); |
55 | } | |
56 | ||
57 | int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb) | |
58 | { | |
59 | int err; | |
60 | ||
df9dcb45 | 61 | err = xfrm_inner_extract_output(x, skb); |
36cf9acf HX |
62 | if (err) |
63 | return err; | |
64 | ||
5596732f | 65 | IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; |
044a832a | 66 | skb->protocol = htons(ETH_P_IP); |
36cf9acf HX |
67 | |
68 | return x->outer_mode->output2(x, skb); | |
69 | } | |
70 | EXPORT_SYMBOL(xfrm4_prepare_output); | |
71 | ||
43a4dea4 | 72 | int xfrm4_output_finish(struct sk_buff *skb) |
09b8f7a9 | 73 | { |
5596732f | 74 | memset(IPCB(skb), 0, sizeof(*IPCB(skb))); |
5596732f SK |
75 | |
76 | #ifdef CONFIG_NETFILTER | |
77 | IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; | |
78 | #endif | |
79 | ||
80 | return xfrm_output(skb); | |
81 | } | |
82 | ||
83 | static int __xfrm4_output(struct sk_buff *skb) | |
84 | { | |
85 | struct xfrm_state *x = skb_dst(skb)->xfrm; | |
86 | ||
09b8f7a9 | 87 | #ifdef CONFIG_NETFILTER |
5596732f | 88 | if (!x) { |
09b8f7a9 HX |
89 | IPCB(skb)->flags |= IPSKB_REROUTED; |
90 | return dst_output(skb); | |
91 | } | |
862b82c6 | 92 | #endif |
09b8f7a9 | 93 | |
5596732f | 94 | return x->outer_mode->afinfo->output_finish(skb); |
09b8f7a9 HX |
95 | } |
96 | ||
aad88724 | 97 | int xfrm4_output(struct sock *sk, struct sk_buff *skb) |
16a6677f | 98 | { |
9bbc768a | 99 | return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb, |
5596732f | 100 | NULL, skb_dst(skb)->dev, __xfrm4_output, |
48d5cad8 | 101 | !(IPCB(skb)->flags & IPSKB_REROUTED)); |
16a6677f | 102 | } |
628e341f HFS |
103 | |
104 | void xfrm4_local_error(struct sk_buff *skb, u32 mtu) | |
105 | { | |
106 | struct iphdr *hdr; | |
107 | ||
108 | hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb); | |
109 | ip_local_error(skb->sk, EMSGSIZE, hdr->daddr, | |
110 | inet_sk(skb->sk)->inet_dport, mtu); | |
111 | } |