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 | { | |
eddc9ec5 | 19 | struct iphdr *outer_iph = ip_hdr(skb); |
b59f45d0 HX |
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)) | |
0660e03f | 29 | IP6_ECN_set_ce(ipv6_hdr(skb)); |
c82f963e MK |
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 | ||
eddc9ec5 | 49 | iph = ip_hdr(skb); |
b59f45d0 HX |
50 | skb->h.ipiph = iph; |
51 | ||
e2d1bca7 ACM |
52 | skb_push(skb, x->props.header_len); |
53 | skb_reset_network_header(skb); | |
eddc9ec5 | 54 | top_iph = ip_hdr(skb); |
b59f45d0 HX |
55 | |
56 | top_iph->ihl = 5; | |
57 | top_iph->version = 4; | |
58 | ||
c82f963e MK |
59 | flags = x->props.flags; |
60 | ||
b59f45d0 | 61 | /* DS disclosed */ |
c82f963e MK |
62 | if (xdst->route->ops->family == AF_INET) { |
63 | top_iph->protocol = IPPROTO_IPIP; | |
64 | top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos); | |
65 | top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ? | |
66 | 0 : (iph->frag_off & htons(IP_DF)); | |
67 | } | |
68 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
69 | else { | |
70 | struct ipv6hdr *ipv6h = (struct ipv6hdr*)iph; | |
71 | top_iph->protocol = IPPROTO_IPV6; | |
72 | top_iph->tos = INET_ECN_encapsulate(iph->tos, ipv6_get_dsfield(ipv6h)); | |
73 | top_iph->frag_off = 0; | |
74 | } | |
75 | #endif | |
b59f45d0 | 76 | |
b59f45d0 HX |
77 | if (flags & XFRM_STATE_NOECN) |
78 | IP_ECN_clear(top_iph); | |
79 | ||
b59f45d0 HX |
80 | if (!top_iph->frag_off) |
81 | __ip_select_ident(top_iph, dst->child, 0); | |
82 | ||
83 | top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT); | |
84 | ||
85 | top_iph->saddr = x->props.saddr.a4; | |
86 | top_iph->daddr = x->id.daddr.a4; | |
b59f45d0 HX |
87 | |
88 | memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options)); | |
89 | return 0; | |
90 | } | |
91 | ||
92 | static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb) | |
93 | { | |
eddc9ec5 | 94 | struct iphdr *iph = ip_hdr(skb); |
39f69c6f | 95 | const unsigned char *old_mac; |
b59f45d0 HX |
96 | int err = -EINVAL; |
97 | ||
132adf54 | 98 | switch (iph->protocol){ |
c82f963e | 99 | case IPPROTO_IPIP: |
e2e01bfe | 100 | break; |
c82f963e MK |
101 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) |
102 | case IPPROTO_IPV6: | |
103 | break; | |
104 | #endif | |
105 | default: | |
106 | goto out; | |
107 | } | |
108 | ||
b59f45d0 HX |
109 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
110 | goto out; | |
111 | ||
112 | if (skb_cloned(skb) && | |
113 | (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC))) | |
114 | goto out; | |
115 | ||
eddc9ec5 | 116 | iph = ip_hdr(skb); |
c82f963e MK |
117 | if (iph->protocol == IPPROTO_IPIP) { |
118 | if (x->props.flags & XFRM_STATE_DECAP_DSCP) | |
119 | ipv4_copy_dscp(iph, skb->h.ipiph); | |
120 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
121 | ipip_ecn_decapsulate(skb); | |
122 | } | |
123 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
124 | else { | |
125 | if (!(x->props.flags & XFRM_STATE_NOECN)) | |
126 | ipip6_ecn_decapsulate(iph, skb); | |
127 | skb->protocol = htons(ETH_P_IPV6); | |
128 | } | |
129 | #endif | |
98e399f8 | 130 | old_mac = skb_mac_header(skb); |
39f69c6f | 131 | skb_set_mac_header(skb, -skb->mac_len); |
98e399f8 | 132 | memmove(skb_mac_header(skb), old_mac, skb->mac_len); |
c1d2bbe1 | 133 | skb_reset_network_header(skb); |
b59f45d0 HX |
134 | err = 0; |
135 | ||
136 | out: | |
137 | return err; | |
138 | } | |
139 | ||
140 | static struct xfrm_mode xfrm4_tunnel_mode = { | |
141 | .input = xfrm4_tunnel_input, | |
142 | .output = xfrm4_tunnel_output, | |
143 | .owner = THIS_MODULE, | |
144 | .encap = XFRM_MODE_TUNNEL, | |
145 | }; | |
146 | ||
147 | static int __init xfrm4_tunnel_init(void) | |
148 | { | |
149 | return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET); | |
150 | } | |
151 | ||
152 | static void __exit xfrm4_tunnel_exit(void) | |
153 | { | |
154 | int err; | |
155 | ||
156 | err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET); | |
157 | BUG_ON(err); | |
158 | } | |
159 | ||
160 | module_init(xfrm4_tunnel_init); | |
161 | module_exit(xfrm4_tunnel_exit); | |
162 | MODULE_LICENSE("GPL"); | |
163 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL); |