1 /*
2 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
3 *
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8 #include <linux/gfp.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/skbuff.h>
13 #include <linux/stringify.h>
14 #include <net/dsfield.h>
15 #include <net/dst.h>
16 #include <net/inet_ecn.h>
17 #include <net/ip6_route.h>
18 #include <net/ipv6.h>
19 #include <net/xfrm.h>
20
21 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
22 {
23 struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
24
25 if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
26 IP6_ECN_set_ce(skb, inner_iph);
27 }
28
29 /* Add encapsulation header.
30 *
31 * The top IP header will be constructed per RFC 2401.
32 */
33 static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
34 {
35 struct dst_entry *dst = skb_dst(skb);
36 struct ipv6hdr *top_iph;
37 int dsfield;
38
39 skb_set_inner_network_header(skb, skb_network_offset(skb));
40 skb_set_inner_transport_header(skb, skb_transport_offset(skb));
41
42 skb_set_network_header(skb, -x->props.header_len);
43 skb->mac_header = skb->network_header +
44 offsetof(struct ipv6hdr, nexthdr);
45 skb->transport_header = skb->network_header + sizeof(*top_iph);
46 top_iph = ipv6_hdr(skb);
47
48 top_iph->version = 6;
49
50 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
51 sizeof(top_iph->flow_lbl));
52 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
53
54 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
55 dsfield = 0;
56 else
57 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
58 dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
59 if (x->props.flags & XFRM_STATE_NOECN)
60 dsfield &= ~INET_ECN_MASK;
61 ipv6_change_dsfield(top_iph, 0, dsfield);
62 top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
63 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
64 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
65 return 0;
66 }
67
68 #define for_each_input_rcu(head, handler) \
69 for (handler = rcu_dereference(head); \
70 handler != NULL; \
71 handler = rcu_dereference(handler->next))
72
73
74 static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
75 {
76 int err = -EINVAL;
77
78 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
79 goto out;
80 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
81 goto out;
82
83 err = skb_unclone(skb, GFP_ATOMIC);
84 if (err)
85 goto out;
86
87 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
88 ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
89 ipipv6_hdr(skb));
90 if (!(x->props.flags & XFRM_STATE_NOECN))
91 ipip6_ecn_decapsulate(skb);
92
93 skb_reset_network_header(skb);
94 skb_mac_header_rebuild(skb);
95 if (skb->mac_len)
96 eth_hdr(skb)->h_proto = skb->protocol;
97
98 err = 0;
99
100 out:
101 return err;
102 }
103
104 static struct sk_buff *xfrm6_mode_tunnel_gso_segment(struct xfrm_state *x,
105 struct sk_buff *skb,
106 netdev_features_t features)
107 {
108 __skb_push(skb, skb->mac_len);
109 return skb_mac_gso_segment(skb, features);
110 }
111
112 static void xfrm6_mode_tunnel_xmit(struct xfrm_state *x, struct sk_buff *skb)
113 {
114 struct xfrm_offload *xo = xfrm_offload(skb);
115
116 if (xo->flags & XFRM_GSO_SEGMENT)
117 skb->transport_header = skb->network_header + sizeof(struct ipv6hdr);
118
119 skb_reset_mac_len(skb);
120 pskb_pull(skb, skb->mac_len + x->props.header_len);
121 }
122
123 static struct xfrm_mode xfrm6_tunnel_mode = {
124 .input2 = xfrm6_mode_tunnel_input,
125 .input = xfrm_prepare_input,
126 .output2 = xfrm6_mode_tunnel_output,
127 .output = xfrm6_prepare_output,
128 .gso_segment = xfrm6_mode_tunnel_gso_segment,
129 .xmit = xfrm6_mode_tunnel_xmit,
130 .owner = THIS_MODULE,
131 .encap = XFRM_MODE_TUNNEL,
132 .flags = XFRM_MODE_FLAG_TUNNEL,
133 };
134
135 static int __init xfrm6_mode_tunnel_init(void)
136 {
137 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
138 }
139
140 static void __exit xfrm6_mode_tunnel_exit(void)
141 {
142 int err;
143
144 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
145 BUG_ON(err);
146 }
147
148 module_init(xfrm6_mode_tunnel_init);
149 module_exit(xfrm6_mode_tunnel_exit);
150 MODULE_LICENSE("GPL");
151 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
152
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