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1/*
2 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
3 *
4 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
5 */
6
7#include <linux/gfp.h>
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/stringify.h>
13#include <net/dst.h>
14#include <net/inet_ecn.h>
15#include <net/ip.h>
16#include <net/xfrm.h>
17
18static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
19{
20 struct iphdr *inner_iph = ipip_hdr(skb);
21
22 if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
23 IP_ECN_set_ce(inner_iph);
24}
25
26/* Add encapsulation header.
27 *
28 * The top IP header will be constructed per RFC 2401.
29 */
30static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
31{
32 struct dst_entry *dst = skb_dst(skb);
33 struct iphdr *top_iph;
34 int flags;
35
36 skb_set_network_header(skb, -x->props.header_len);
37 skb->mac_header = skb->network_header +
38 offsetof(struct iphdr, protocol);
39 skb->transport_header = skb->network_header + sizeof(*top_iph);
40 top_iph = ip_hdr(skb);
41
42 top_iph->ihl = 5;
43 top_iph->version = 4;
44
45 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
46
47 /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
48 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
49 top_iph->tos = 0;
50 else
51 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
52 top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
53 XFRM_MODE_SKB_CB(skb)->tos);
54
55 flags = x->props.flags;
56 if (flags & XFRM_STATE_NOECN)
57 IP_ECN_clear(top_iph);
58
59 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
60 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
61 ip_select_ident(skb, dst->child, NULL);
62
63 top_iph->ttl = ip4_dst_hoplimit(dst->child);
64
65 top_iph->saddr = x->props.saddr.a4;
66 top_iph->daddr = x->id.daddr.a4;
67
68 return 0;
69}
70
71static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
72{
73 int err = -EINVAL;
74
75 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
76 goto out;
77
78 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
79 goto out;
80
81 err = skb_unclone(skb, GFP_ATOMIC);
82 if (err)
83 goto out;
84
85 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
86 ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
87 if (!(x->props.flags & XFRM_STATE_NOECN))
88 ipip_ecn_decapsulate(skb);
89
90 skb_reset_network_header(skb);
91 skb_mac_header_rebuild(skb);
92
93 err = 0;
94
95out:
96 return err;
97}
98
99static struct xfrm_mode xfrm4_tunnel_mode = {
100 .input2 = xfrm4_mode_tunnel_input,
101 .input = xfrm_prepare_input,
102 .output2 = xfrm4_mode_tunnel_output,
103 .output = xfrm4_prepare_output,
104 .owner = THIS_MODULE,
105 .encap = XFRM_MODE_TUNNEL,
106 .flags = XFRM_MODE_FLAG_TUNNEL,
107};
108
109static int __init xfrm4_mode_tunnel_init(void)
110{
111 return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
112}
113
114static void __exit xfrm4_mode_tunnel_exit(void)
115{
116 int err;
117
118 err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
119 BUG_ON(err);
120}
121
122module_init(xfrm4_mode_tunnel_init);
123module_exit(xfrm4_mode_tunnel_exit);
124MODULE_LICENSE("GPL");
125MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);
1/*
2 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
3 *
4 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
5 */
6
7#include <linux/gfp.h>
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/stringify.h>
13#include <net/dst.h>
14#include <net/inet_ecn.h>
15#include <net/ip.h>
16#include <net/xfrm.h>
17
18static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
19{
20 struct iphdr *inner_iph = ipip_hdr(skb);
21
22 if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
23 IP_ECN_set_ce(inner_iph);
24}
25
26/* Add encapsulation header.
27 *
28 * The top IP header will be constructed per RFC 2401.
29 */
30static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
31{
32 struct dst_entry *dst = skb_dst(skb);
33 struct iphdr *top_iph;
34 int flags;
35
36 skb_set_network_header(skb, -x->props.header_len);
37 skb->mac_header = skb->network_header +
38 offsetof(struct iphdr, protocol);
39 skb->transport_header = skb->network_header + sizeof(*top_iph);
40 top_iph = ip_hdr(skb);
41
42 top_iph->ihl = 5;
43 top_iph->version = 4;
44
45 top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
46
47 /* DS disclosed */
48 top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos,
49 XFRM_MODE_SKB_CB(skb)->tos);
50
51 flags = x->props.flags;
52 if (flags & XFRM_STATE_NOECN)
53 IP_ECN_clear(top_iph);
54
55 top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
56 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
57 ip_select_ident(top_iph, dst->child, NULL);
58
59 top_iph->ttl = ip4_dst_hoplimit(dst->child);
60
61 top_iph->saddr = x->props.saddr.a4;
62 top_iph->daddr = x->id.daddr.a4;
63
64 return 0;
65}
66
67static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
68{
69 const unsigned char *old_mac;
70 int err = -EINVAL;
71
72 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP)
73 goto out;
74
75 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
76 goto out;
77
78 if (skb_cloned(skb) &&
79 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
80 goto out;
81
82 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
83 ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb));
84 if (!(x->props.flags & XFRM_STATE_NOECN))
85 ipip_ecn_decapsulate(skb);
86
87 old_mac = skb_mac_header(skb);
88 skb_set_mac_header(skb, -skb->mac_len);
89 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
90 skb_reset_network_header(skb);
91 err = 0;
92
93out:
94 return err;
95}
96
97static struct xfrm_mode xfrm4_tunnel_mode = {
98 .input2 = xfrm4_mode_tunnel_input,
99 .input = xfrm_prepare_input,
100 .output2 = xfrm4_mode_tunnel_output,
101 .output = xfrm4_prepare_output,
102 .owner = THIS_MODULE,
103 .encap = XFRM_MODE_TUNNEL,
104 .flags = XFRM_MODE_FLAG_TUNNEL,
105};
106
107static int __init xfrm4_mode_tunnel_init(void)
108{
109 return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
110}
111
112static void __exit xfrm4_mode_tunnel_exit(void)
113{
114 int err;
115
116 err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
117 BUG_ON(err);
118}
119
120module_init(xfrm4_mode_tunnel_init);
121module_exit(xfrm4_mode_tunnel_exit);
122MODULE_LICENSE("GPL");
123MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);