Commit | Line | Data |
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b59f45d0 HX |
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/init.h> | |
8 | #include <linux/kernel.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/skbuff.h> | |
11 | #include <linux/stringify.h> | |
12 | #include <net/dst.h> | |
13 | #include <net/inet_ecn.h> | |
14 | #include <net/ip.h> | |
15 | #include <net/xfrm.h> | |
16 | ||
17 | static inline void ipip_ecn_decapsulate(struct sk_buff *skb) | |
18 | { | |
b0061ce4 | 19 | struct iphdr *inner_iph = ipip_hdr(skb); |
b59f45d0 | 20 | |
227620e2 | 21 | if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos)) |
b59f45d0 HX |
22 | IP_ECN_set_ce(inner_iph); |
23 | } | |
24 | ||
25 | /* Add encapsulation header. | |
26 | * | |
ceb1eec8 | 27 | * The top IP header will be constructed per RFC 2401. |
b59f45d0 | 28 | */ |
195ad6a3 | 29 | static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) |
b59f45d0 HX |
30 | { |
31 | struct dst_entry *dst = skb->dst; | |
36cf9acf | 32 | struct iphdr *top_iph; |
b59f45d0 HX |
33 | int flags; |
34 | ||
7b277b1a | 35 | skb_set_network_header(skb, -x->props.header_len); |
37fedd3a HX |
36 | skb->mac_header = skb->network_header + |
37 | offsetof(struct iphdr, protocol); | |
36cf9acf | 38 | skb->transport_header = skb->network_header + sizeof(*top_iph); |
eddc9ec5 | 39 | top_iph = ip_hdr(skb); |
b59f45d0 HX |
40 | |
41 | top_iph->ihl = 5; | |
42 | top_iph->version = 4; | |
43 | ||
df9dcb45 | 44 | top_iph->protocol = xfrm_af2proto(skb->dst->ops->family); |
c82f963e | 45 | |
b59f45d0 | 46 | /* DS disclosed */ |
36cf9acf HX |
47 | top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos, |
48 | XFRM_MODE_SKB_CB(skb)->tos); | |
b59f45d0 | 49 | |
36cf9acf | 50 | flags = x->props.flags; |
b59f45d0 HX |
51 | if (flags & XFRM_STATE_NOECN) |
52 | IP_ECN_clear(top_iph); | |
53 | ||
36cf9acf | 54 | top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? |
fe833fca | 55 | 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); |
36cf9acf | 56 | ip_select_ident(top_iph, dst->child, NULL); |
b59f45d0 HX |
57 | |
58 | top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT); | |
59 | ||
60 | top_iph->saddr = x->props.saddr.a4; | |
61 | top_iph->daddr = x->id.daddr.a4; | |
b59f45d0 | 62 | |
b59f45d0 HX |
63 | return 0; |
64 | } | |
65 | ||
195ad6a3 | 66 | static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) |
b59f45d0 | 67 | { |
39f69c6f | 68 | const unsigned char *old_mac; |
b59f45d0 HX |
69 | int err = -EINVAL; |
70 | ||
227620e2 HX |
71 | if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPIP) |
72 | goto out; | |
c82f963e | 73 | |
b59f45d0 HX |
74 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
75 | goto out; | |
76 | ||
77 | if (skb_cloned(skb) && | |
78 | (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) | |
79 | goto out; | |
80 | ||
227620e2 HX |
81 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) |
82 | ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, ipip_hdr(skb)); | |
83 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
84 | ipip_ecn_decapsulate(skb); | |
85 | ||
98e399f8 | 86 | old_mac = skb_mac_header(skb); |
39f69c6f | 87 | skb_set_mac_header(skb, -skb->mac_len); |
98e399f8 | 88 | memmove(skb_mac_header(skb), old_mac, skb->mac_len); |
c1d2bbe1 | 89 | skb_reset_network_header(skb); |
b59f45d0 HX |
90 | err = 0; |
91 | ||
92 | out: | |
93 | return err; | |
94 | } | |
95 | ||
96 | static struct xfrm_mode xfrm4_tunnel_mode = { | |
195ad6a3 | 97 | .input2 = xfrm4_mode_tunnel_input, |
227620e2 | 98 | .input = xfrm_prepare_input, |
195ad6a3 | 99 | .output2 = xfrm4_mode_tunnel_output, |
36cf9acf | 100 | .output = xfrm4_prepare_output, |
b59f45d0 HX |
101 | .owner = THIS_MODULE, |
102 | .encap = XFRM_MODE_TUNNEL, | |
1bfcb10f | 103 | .flags = XFRM_MODE_FLAG_TUNNEL, |
b59f45d0 HX |
104 | }; |
105 | ||
195ad6a3 | 106 | static int __init xfrm4_mode_tunnel_init(void) |
b59f45d0 HX |
107 | { |
108 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); | |
109 | } | |
110 | ||
195ad6a3 | 111 | static void __exit xfrm4_mode_tunnel_exit(void) |
b59f45d0 HX |
112 | { |
113 | int err; | |
114 | ||
115 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); | |
116 | BUG_ON(err); | |
117 | } | |
118 | ||
195ad6a3 HX |
119 | module_init(xfrm4_mode_tunnel_init); |
120 | module_exit(xfrm4_mode_tunnel_exit); | |
b59f45d0 HX |
121 | MODULE_LICENSE("GPL"); |
122 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |