Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * xfrm6_output.c - Common IPsec encapsulation code for IPv6. | |
3 | * Copyright (C) 2002 USAGI/WIDE Project | |
4 | * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/skbuff.h> | |
13 | #include <linux/spinlock.h> | |
14 | #include <linux/icmpv6.h> | |
15 | #include <net/dsfield.h> | |
16 | #include <net/inet_ecn.h> | |
17 | #include <net/ipv6.h> | |
18 | #include <net/xfrm.h> | |
19 | ||
20 | /* Add encapsulation header. | |
21 | * | |
22 | * In transport mode, the IP header and mutable extension headers will be moved | |
23 | * forward to make space for the encapsulation header. | |
24 | * | |
25 | * In tunnel mode, the top IP header will be constructed per RFC 2401. | |
26 | * The following fields in it shall be filled in by x->type->output: | |
27 | * payload_len | |
28 | * | |
29 | * On exit, skb->h will be set to the start of the encapsulation header to be | |
30 | * filled in by x->type->output and skb->nh will be set to the nextheader field | |
31 | * of the extension header directly preceding the encapsulation header, or in | |
32 | * its absence, that of the top IP header. The value of skb->data will always | |
33 | * point to the top IP header. | |
34 | */ | |
35 | static void xfrm6_encap(struct sk_buff *skb) | |
36 | { | |
37 | struct dst_entry *dst = skb->dst; | |
38 | struct xfrm_state *x = dst->xfrm; | |
39 | struct ipv6hdr *iph, *top_iph; | |
40 | int dsfield; | |
41 | ||
42 | skb_push(skb, x->props.header_len); | |
43 | iph = skb->nh.ipv6h; | |
44 | ||
45 | if (!x->props.mode) { | |
46 | u8 *prevhdr; | |
47 | int hdr_len; | |
48 | ||
49 | hdr_len = ip6_find_1stfragopt(skb, &prevhdr); | |
50 | skb->nh.raw = prevhdr - x->props.header_len; | |
51 | skb->h.raw = skb->data + hdr_len; | |
52 | memmove(skb->data, iph, hdr_len); | |
53 | return; | |
54 | } | |
55 | ||
56 | skb->nh.raw = skb->data; | |
57 | top_iph = skb->nh.ipv6h; | |
58 | skb->nh.raw = &top_iph->nexthdr; | |
59 | skb->h.ipv6h = top_iph + 1; | |
60 | ||
61 | top_iph->version = 6; | |
62 | top_iph->priority = iph->priority; | |
63 | top_iph->flow_lbl[0] = iph->flow_lbl[0]; | |
64 | top_iph->flow_lbl[1] = iph->flow_lbl[1]; | |
65 | top_iph->flow_lbl[2] = iph->flow_lbl[2]; | |
66 | dsfield = ipv6_get_dsfield(top_iph); | |
67 | dsfield = INET_ECN_encapsulate(dsfield, dsfield); | |
68 | if (x->props.flags & XFRM_STATE_NOECN) | |
69 | dsfield &= ~INET_ECN_MASK; | |
70 | ipv6_change_dsfield(top_iph, 0, dsfield); | |
71 | top_iph->nexthdr = IPPROTO_IPV6; | |
72 | top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT); | |
73 | ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr); | |
74 | ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr); | |
75 | } | |
76 | ||
77 | static int xfrm6_tunnel_check_size(struct sk_buff *skb) | |
78 | { | |
79 | int mtu, ret = 0; | |
80 | struct dst_entry *dst = skb->dst; | |
81 | ||
82 | mtu = dst_mtu(dst); | |
83 | if (mtu < IPV6_MIN_MTU) | |
84 | mtu = IPV6_MIN_MTU; | |
85 | ||
86 | if (skb->len > mtu) { | |
87 | icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); | |
88 | ret = -EMSGSIZE; | |
89 | } | |
90 | ||
91 | return ret; | |
92 | } | |
93 | ||
94 | int xfrm6_output(struct sk_buff *skb) | |
95 | { | |
96 | struct dst_entry *dst = skb->dst; | |
97 | struct xfrm_state *x = dst->xfrm; | |
98 | int err; | |
99 | ||
100 | if (skb->ip_summed == CHECKSUM_HW) { | |
101 | err = skb_checksum_help(skb, 0); | |
102 | if (err) | |
103 | goto error_nolock; | |
104 | } | |
105 | ||
106 | if (x->props.mode) { | |
107 | err = xfrm6_tunnel_check_size(skb); | |
108 | if (err) | |
109 | goto error_nolock; | |
110 | } | |
111 | ||
112 | spin_lock_bh(&x->lock); | |
113 | err = xfrm_state_check(x, skb); | |
114 | if (err) | |
115 | goto error; | |
116 | ||
117 | xfrm6_encap(skb); | |
118 | ||
119 | err = x->type->output(x, skb); | |
120 | if (err) | |
121 | goto error; | |
122 | ||
123 | x->curlft.bytes += skb->len; | |
124 | x->curlft.packets++; | |
125 | ||
126 | spin_unlock_bh(&x->lock); | |
127 | ||
128 | skb->nh.raw = skb->data; | |
129 | ||
130 | if (!(skb->dst = dst_pop(dst))) { | |
131 | err = -EHOSTUNREACH; | |
132 | goto error_nolock; | |
133 | } | |
134 | err = NET_XMIT_BYPASS; | |
135 | ||
136 | out_exit: | |
137 | return err; | |
138 | error: | |
139 | spin_unlock_bh(&x->lock); | |
140 | error_nolock: | |
141 | kfree_skb(skb); | |
142 | goto out_exit; | |
143 | } |