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>
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.
12 #include <linux/skbuff.h>
13 #include <linux/spinlock.h>
14 #include <linux/icmpv6.h>
15 #include <net/inet_ecn.h>
19 /* Add encapsulation header.
21 * In transport mode, the IP header and mutable extension headers will be moved
22 * forward to make space for the encapsulation header.
24 * In tunnel mode, the top IP header will be constructed per RFC 2401.
25 * The following fields in it shall be filled in by x->type->output:
28 * On exit, skb->h will be set to the start of the encapsulation header to be
29 * filled in by x->type->output and skb->nh will be set to the nextheader field
30 * of the extension header directly preceding the encapsulation header, or in
31 * its absence, that of the top IP header. The value of skb->data will always
32 * point to the top IP header.
34 static void xfrm6_encap(struct sk_buff *skb)
36 struct dst_entry *dst = skb->dst;
37 struct xfrm_state *x = dst->xfrm;
38 struct ipv6hdr *iph, *top_iph;
40 skb_push(skb, x->props.header_len);
47 hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
48 skb->nh.raw = prevhdr - x->props.header_len;
49 skb->h.raw = skb->data + hdr_len;
50 memmove(skb->data, iph, hdr_len);
54 skb->nh.raw = skb->data;
55 top_iph = skb->nh.ipv6h;
56 skb->nh.raw = &top_iph->nexthdr;
57 skb->h.ipv6h = top_iph + 1;
60 top_iph->priority = iph->priority;
61 if (x->props.flags & XFRM_STATE_NOECN)
62 IP6_ECN_clear(top_iph);
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 top_iph->nexthdr = IPPROTO_IPV6;
67 top_iph->hop_limit = iph->hop_limit;
68 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
69 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
72 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
75 struct dst_entry *dst = skb->dst;
77 mtu = dst_pmtu(dst) - sizeof(struct ipv6hdr);
78 if (mtu < IPV6_MIN_MTU)
82 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
89 int xfrm6_output(struct sk_buff **pskb)
91 struct sk_buff *skb = *pskb;
92 struct dst_entry *dst = skb->dst;
93 struct xfrm_state *x = dst->xfrm;
96 if (skb->ip_summed == CHECKSUM_HW) {
97 err = skb_checksum_help(pskb, 0);
103 spin_lock_bh(&x->lock);
104 err = xfrm_state_check(x, skb);
109 err = xfrm6_tunnel_check_size(skb);
116 err = x->type->output(pskb);
121 x->curlft.bytes += skb->len;
124 spin_unlock_bh(&x->lock);
126 skb->nh.raw = skb->data;
128 if (!(skb->dst = dst_pop(dst))) {
132 err = NET_XMIT_BYPASS;
137 spin_unlock_bh(&x->lock);