2 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
3 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
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.
11 #include <linux/if_ether.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/netfilter_ipv4.h>
21 static int xfrm4_tunnel_check_size(struct sk_buff
*skb
)
25 if (IPCB(skb
)->flags
& IPSKB_XFRM_TUNNEL_SIZE
)
28 if (!(ip_hdr(skb
)->frag_off
& htons(IP_DF
)) || skb
->ignore_df
)
31 mtu
= dst_mtu(skb_dst(skb
));
34 xfrm_local_error(skb
, mtu
);
36 icmp_send(skb
, ICMP_DEST_UNREACH
,
37 ICMP_FRAG_NEEDED
, htonl(mtu
));
44 int xfrm4_extract_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
48 err
= xfrm4_tunnel_check_size(skb
);
52 XFRM_MODE_SKB_CB(skb
)->protocol
= ip_hdr(skb
)->protocol
;
54 return xfrm4_extract_header(skb
);
57 int xfrm4_prepare_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
61 err
= xfrm_inner_extract_output(x
, skb
);
65 IPCB(skb
)->flags
|= IPSKB_XFRM_TUNNEL_SIZE
;
67 return x
->outer_mode
->output2(x
, skb
);
69 EXPORT_SYMBOL(xfrm4_prepare_output
);
71 int xfrm4_output_finish(struct sk_buff
*skb
)
73 memset(IPCB(skb
), 0, sizeof(*IPCB(skb
)));
74 skb
->protocol
= htons(ETH_P_IP
);
76 #ifdef CONFIG_NETFILTER
77 IPCB(skb
)->flags
|= IPSKB_XFRM_TRANSFORMED
;
80 return xfrm_output(skb
);
83 static int __xfrm4_output(struct sk_buff
*skb
)
85 struct xfrm_state
*x
= skb_dst(skb
)->xfrm
;
87 #ifdef CONFIG_NETFILTER
89 IPCB(skb
)->flags
|= IPSKB_REROUTED
;
90 return dst_output(skb
);
94 return x
->outer_mode
->afinfo
->output_finish(skb
);
97 int xfrm4_output(struct sock
*sk
, struct sk_buff
*skb
)
99 return NF_HOOK_COND(NFPROTO_IPV4
, NF_INET_POST_ROUTING
, skb
,
100 NULL
, skb_dst(skb
)->dev
, __xfrm4_output
,
101 !(IPCB(skb
)->flags
& IPSKB_REROUTED
));
104 void xfrm4_local_error(struct sk_buff
*skb
, u32 mtu
)
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
);
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