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
)
24 struct dst_entry
*dst
;
26 if (IPCB(skb
)->flags
& IPSKB_XFRM_TUNNEL_SIZE
)
29 if (!(ip_hdr(skb
)->frag_off
& htons(IP_DF
)) || skb
->local_df
)
35 icmp_send(skb
, ICMP_DEST_UNREACH
, ICMP_FRAG_NEEDED
, htonl(mtu
));
42 int xfrm4_extract_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
46 err
= xfrm4_tunnel_check_size(skb
);
50 XFRM_MODE_SKB_CB(skb
)->protocol
= ip_hdr(skb
)->protocol
;
52 return xfrm4_extract_header(skb
);
55 int xfrm4_prepare_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
59 err
= xfrm_inner_extract_output(x
, skb
);
63 memset(IPCB(skb
), 0, sizeof(*IPCB(skb
)));
64 IPCB(skb
)->flags
|= IPSKB_XFRM_TUNNEL_SIZE
| IPSKB_XFRM_TRANSFORMED
;
66 skb
->protocol
= htons(ETH_P_IP
);
68 return x
->outer_mode
->output2(x
, skb
);
70 EXPORT_SYMBOL(xfrm4_prepare_output
);
72 static int xfrm4_output_finish(struct sk_buff
*skb
)
74 #ifdef CONFIG_NETFILTER
75 if (!skb_dst(skb
)->xfrm
) {
76 IPCB(skb
)->flags
|= IPSKB_REROUTED
;
77 return dst_output(skb
);
80 IPCB(skb
)->flags
|= IPSKB_XFRM_TRANSFORMED
;
83 skb
->protocol
= htons(ETH_P_IP
);
84 return xfrm_output(skb
);
87 int xfrm4_output(struct sk_buff
*skb
)
89 return NF_HOOK_COND(PF_INET
, NF_INET_POST_ROUTING
, skb
,
90 NULL
, skb_dst(skb
)->dev
, xfrm4_output_finish
,
91 !(IPCB(skb
)->flags
& IPSKB_REROUTED
));
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