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 | { | |
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 | ||
c82f963e MK |
26 | static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb) |
27 | { | |
28 | if (INET_ECN_is_ce(iph->tos)) | |
29 | IP6_ECN_set_ce(skb->nh.ipv6h); | |
30 | } | |
31 | ||
b59f45d0 HX |
32 | /* Add encapsulation header. |
33 | * | |
34 | * The top IP header will be constructed per RFC 2401. The following fields | |
35 | * in it shall be filled in by x->type->output: | |
36 | * tot_len | |
37 | * check | |
38 | * | |
39 | * On exit, skb->h will be set to the start of the payload to be processed | |
40 | * by x->type->output and skb->nh will be set to the top IP header. | |
41 | */ | |
eb878e84 | 42 | static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) |
b59f45d0 HX |
43 | { |
44 | struct dst_entry *dst = skb->dst; | |
c82f963e | 45 | struct xfrm_dst *xdst = (struct xfrm_dst*)dst; |
b59f45d0 HX |
46 | struct iphdr *iph, *top_iph; |
47 | int flags; | |
48 | ||
49 | iph = skb->nh.iph; | |
50 | skb->h.ipiph = iph; | |
51 | ||
52 | skb->nh.raw = skb_push(skb, x->props.header_len); | |
53 | top_iph = skb->nh.iph; | |
54 | ||
55 | top_iph->ihl = 5; | |
56 | top_iph->version = 4; | |
57 | ||
c82f963e MK |
58 | flags = x->props.flags; |
59 | ||
b59f45d0 | 60 | /* DS disclosed */ |
c82f963e MK |
61 | if (xdst->route->ops->family == AF_INET) { |
62 | top_iph->protocol = IPPROTO_IPIP; | |
63 | top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos); | |
64 | top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? | |
65 | 0 : (iph->frag_off & htons(IP_DF)); | |
66 | } | |
67 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
68 | else { | |
69 | struct ipv6hdr *ipv6h = (struct ipv6hdr*)iph; | |
70 | top_iph->protocol = IPPROTO_IPV6; | |
71 | top_iph->tos = INET_ECN_encapsulate(iph->tos, ipv6_get_dsfield(ipv6h)); | |
72 | top_iph->frag_off = 0; | |
73 | } | |
74 | #endif | |
b59f45d0 | 75 | |
b59f45d0 HX |
76 | if (flags & XFRM_STATE_NOECN) |
77 | IP_ECN_clear(top_iph); | |
78 | ||
b59f45d0 HX |
79 | if (!top_iph->frag_off) |
80 | __ip_select_ident(top_iph, dst->child, 0); | |
81 | ||
82 | top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT); | |
83 | ||
84 | top_iph->saddr = x->props.saddr.a4; | |
85 | top_iph->daddr = x->id.daddr.a4; | |
b59f45d0 HX |
86 | |
87 | memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options)); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) | |
92 | { | |
93 | struct iphdr *iph = skb->nh.iph; | |
39f69c6f | 94 | const unsigned char *old_mac; |
b59f45d0 HX |
95 | int err = -EINVAL; |
96 | ||
132adf54 | 97 | switch (iph->protocol){ |
c82f963e | 98 | case IPPROTO_IPIP: |
e2e01bfe | 99 | break; |
c82f963e MK |
100 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) |
101 | case IPPROTO_IPV6: | |
102 | break; | |
103 | #endif | |
104 | default: | |
105 | goto out; | |
106 | } | |
107 | ||
b59f45d0 HX |
108 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
109 | goto out; | |
110 | ||
111 | if (skb_cloned(skb) && | |
112 | (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) | |
113 | goto out; | |
114 | ||
e4396b54 | 115 | iph = skb->nh.iph; |
c82f963e MK |
116 | if (iph->protocol == IPPROTO_IPIP) { |
117 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) | |
118 | ipv4_copy_dscp(iph, skb->h.ipiph); | |
119 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
120 | ipip_ecn_decapsulate(skb); | |
121 | } | |
122 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
123 | else { | |
124 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
125 | ipip6_ecn_decapsulate(iph, skb); | |
126 | skb->protocol = htons(ETH_P_IPV6); | |
127 | } | |
128 | #endif | |
98e399f8 | 129 | old_mac = skb_mac_header(skb); |
39f69c6f | 130 | skb_set_mac_header(skb, -skb->mac_len); |
98e399f8 | 131 | memmove(skb_mac_header(skb), old_mac, skb->mac_len); |
c1d2bbe1 | 132 | skb_reset_network_header(skb); |
b59f45d0 HX |
133 | err = 0; |
134 | ||
135 | out: | |
136 | return err; | |
137 | } | |
138 | ||
139 | static struct xfrm_mode xfrm4_tunnel_mode = { | |
140 | .input = xfrm4_tunnel_input, | |
141 | .output = xfrm4_tunnel_output, | |
142 | .owner = THIS_MODULE, | |
143 | .encap = XFRM_MODE_TUNNEL, | |
144 | }; | |
145 | ||
146 | static int __init xfrm4_tunnel_init(void) | |
147 | { | |
148 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); | |
149 | } | |
150 | ||
151 | static void __exit xfrm4_tunnel_exit(void) | |
152 | { | |
153 | int err; | |
154 | ||
155 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); | |
156 | BUG_ON(err); | |
157 | } | |
158 | ||
159 | module_init(xfrm4_tunnel_init); | |
160 | module_exit(xfrm4_tunnel_exit); | |
161 | MODULE_LICENSE("GPL"); | |
162 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |