[SK_BUFF] xfrm: Use skb_set_mac_header in the memmove cases
[linux-2.6.22.y-op.git] / net / ipv4 / xfrm4_mode_tunnel.c
blobf09055d3a76866acd3d9ab51f9e8f198492ae8f6
1 /*
2 * xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
4 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
5 */
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>
17 static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
19 struct iphdr *outer_iph = skb->nh.iph;
20 struct iphdr *inner_iph = skb->h.ipiph;
22 if (INET_ECN_is_ce(outer_iph->tos))
23 IP_ECN_set_ce(inner_iph);
26 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
28 if (INET_ECN_is_ce(iph->tos))
29 IP6_ECN_set_ce(skb->nh.ipv6h);
32 /* Add encapsulation header.
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
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.
42 static int xfrm4_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
44 struct dst_entry *dst = skb->dst;
45 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
46 struct iphdr *iph, *top_iph;
47 int flags;
49 iph = skb->nh.iph;
50 skb->h.ipiph = iph;
52 skb->nh.raw = skb_push(skb, x->props.header_len);
53 top_iph = skb->nh.iph;
55 top_iph->ihl = 5;
56 top_iph->version = 4;
58 flags = x->props.flags;
60 /* DS disclosed */
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));
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;
74 #endif
76 if (flags & XFRM_STATE_NOECN)
77 IP_ECN_clear(top_iph);
79 if (!top_iph->frag_off)
80 __ip_select_ident(top_iph, dst->child, 0);
82 top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
84 top_iph->saddr = x->props.saddr.a4;
85 top_iph->daddr = x->id.daddr.a4;
87 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
88 return 0;
91 static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
93 struct iphdr *iph = skb->nh.iph;
94 const unsigned char *old_mac;
95 int err = -EINVAL;
97 switch (iph->protocol){
98 case IPPROTO_IPIP:
99 break;
100 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
101 case IPPROTO_IPV6:
102 break;
103 #endif
104 default:
105 goto out;
108 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
109 goto out;
111 if (skb_cloned(skb) &&
112 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
113 goto out;
115 iph = skb->nh.iph;
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);
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);
128 #endif
129 old_mac = skb->mac.raw;
130 skb_set_mac_header(skb, -skb->mac_len);
131 memmove(skb->mac.raw, old_mac, skb->mac_len);
132 skb->nh.raw = skb->data;
133 err = 0;
135 out:
136 return err;
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,
146 static int __init xfrm4_tunnel_init(void)
148 return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
151 static void __exit xfrm4_tunnel_exit(void)
153 int err;
155 err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
156 BUG_ON(err);
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);