Commit | Line | Data |
---|---|---|
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 | { | |
19 | struct iphdr *outer_iph = skb->nh.iph; | |
20 | struct iphdr *inner_iph = skb->h.ipiph; | |
21 | ||
22 | if (INET_ECN_is_ce(outer_iph->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. The following fields | |
29 | * in it shall be filled in by x->type->output: | |
30 | * tot_len | |
31 | * check | |
32 | * | |
33 | * On exit, skb->h will be set to the start of the payload to be processed | |
34 | * by x->type->output and skb->nh will be set to the top IP header. | |
35 | */ | |
36 | static int xfrm4_tunnel_output(struct sk_buff *skb) | |
37 | { | |
38 | struct dst_entry *dst = skb->dst; | |
39 | struct xfrm_state *x = dst->xfrm; | |
40 | struct iphdr *iph, *top_iph; | |
41 | int flags; | |
42 | ||
43 | iph = skb->nh.iph; | |
44 | skb->h.ipiph = iph; | |
45 | ||
46 | skb->nh.raw = skb_push(skb, x->props.header_len); | |
47 | top_iph = skb->nh.iph; | |
48 | ||
49 | top_iph->ihl = 5; | |
50 | top_iph->version = 4; | |
51 | ||
52 | /* DS disclosed */ | |
53 | top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->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 : (iph->frag_off & htons(IP_DF)); | |
61 | if (!top_iph->frag_off) | |
62 | __ip_select_ident(top_iph, dst->child, 0); | |
63 | ||
64 | top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT); | |
65 | ||
66 | top_iph->saddr = x->props.saddr.a4; | |
67 | top_iph->daddr = x->id.daddr.a4; | |
68 | top_iph->protocol = IPPROTO_IPIP; | |
69 | ||
70 | memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options)); | |
71 | return 0; | |
72 | } | |
73 | ||
74 | static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) | |
75 | { | |
76 | struct iphdr *iph = skb->nh.iph; | |
77 | int err = -EINVAL; | |
78 | ||
79 | if (iph->protocol != IPPROTO_IPIP) | |
80 | goto out; | |
81 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) | |
82 | goto out; | |
83 | ||
84 | if (skb_cloned(skb) && | |
85 | (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) | |
86 | goto out; | |
87 | ||
88 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) | |
89 | ipv4_copy_dscp(iph, skb->h.ipiph); | |
90 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
91 | ipip_ecn_decapsulate(skb); | |
92 | skb->mac.raw = memmove(skb->data - skb->mac_len, | |
93 | skb->mac.raw, skb->mac_len); | |
94 | skb->nh.raw = skb->data; | |
b59f45d0 HX |
95 | err = 0; |
96 | ||
97 | out: | |
98 | return err; | |
99 | } | |
100 | ||
101 | static struct xfrm_mode xfrm4_tunnel_mode = { | |
102 | .input = xfrm4_tunnel_input, | |
103 | .output = xfrm4_tunnel_output, | |
104 | .owner = THIS_MODULE, | |
105 | .encap = XFRM_MODE_TUNNEL, | |
106 | }; | |
107 | ||
108 | static int __init xfrm4_tunnel_init(void) | |
109 | { | |
110 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); | |
111 | } | |
112 | ||
113 | static void __exit xfrm4_tunnel_exit(void) | |
114 | { | |
115 | int err; | |
116 | ||
117 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); | |
118 | BUG_ON(err); | |
119 | } | |
120 | ||
121 | module_init(xfrm4_tunnel_init); | |
122 | module_exit(xfrm4_tunnel_exit); | |
123 | MODULE_LICENSE("GPL"); | |
124 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |