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/compiler.h>
13#include <linux/skbuff.h>
14#include <linux/spinlock.h>
15#include <linux/icmpv6.h>
16#include <linux/netfilter_ipv6.h>
17#include <net/ipv6.h>
18#include <net/xfrm.h>
19
20int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
21			  u8 **prevhdr)
22{
23	return ip6_find_1stfragopt(skb, prevhdr);
24}
25
26EXPORT_SYMBOL(xfrm6_find_1stfragopt);
27
28static int xfrm6_tunnel_check_size(struct sk_buff *skb)
29{
30	int mtu, ret = 0;
31	struct dst_entry *dst = skb->dst;
32
33	mtu = dst_mtu(dst);
34	if (mtu < IPV6_MIN_MTU)
35		mtu = IPV6_MIN_MTU;
36
37	if (skb->len > mtu) {
38		skb->dev = dst->dev;
39		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
40		ret = -EMSGSIZE;
41	}
42
43	return ret;
44}
45
46static int xfrm6_output_one(struct sk_buff *skb)
47{
48	struct dst_entry *dst = skb->dst;
49	struct xfrm_state *x = dst->xfrm;
50	int err;
51
52	if (skb->ip_summed == CHECKSUM_PARTIAL) {
53		err = skb_checksum_help(skb);
54		if (err)
55			goto error_nolock;
56	}
57
58	if (x->props.mode == XFRM_MODE_TUNNEL) {
59		err = xfrm6_tunnel_check_size(skb);
60		if (err)
61			goto error_nolock;
62	}
63
64	do {
65		spin_lock_bh(&x->lock);
66		err = xfrm_state_check(x, skb);
67		if (err)
68			goto error;
69
70		err = x->mode->output(x, skb);
71		if (err)
72			goto error;
73
74		err = x->type->output(x, skb);
75		if (err)
76			goto error;
77
78		x->curlft.bytes += skb->len;
79		x->curlft.packets++;
80		if (x->props.mode == XFRM_MODE_ROUTEOPTIMIZATION)
81			x->lastused = get_seconds();
82
83		spin_unlock_bh(&x->lock);
84
85		skb_reset_network_header(skb);
86
87		if (!(skb->dst = dst_pop(dst))) {
88			err = -EHOSTUNREACH;
89			goto error_nolock;
90		}
91		dst = skb->dst;
92		x = dst->xfrm;
93	} while (x && (x->props.mode != XFRM_MODE_TUNNEL));
94
95	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
96	err = 0;
97
98out_exit:
99	return err;
100error:
101	spin_unlock_bh(&x->lock);
102error_nolock:
103	kfree_skb(skb);
104	goto out_exit;
105}
106
107static int xfrm6_output_finish2(struct sk_buff *skb)
108{
109	int err;
110
111	while (likely((err = xfrm6_output_one(skb)) == 0)) {
112		nf_reset(skb);
113
114		err = nf_hook(PF_INET6, NF_IP6_LOCAL_OUT, &skb, NULL,
115			      skb->dst->dev, dst_output);
116		if (unlikely(err != 1))
117			break;
118
119		if (!skb->dst->xfrm)
120			return dst_output(skb);
121
122		err = nf_hook(PF_INET6, NF_IP6_POST_ROUTING, &skb, NULL,
123			      skb->dst->dev, xfrm6_output_finish2);
124		if (unlikely(err != 1))
125			break;
126	}
127
128	return err;
129}
130
131static int xfrm6_output_finish(struct sk_buff *skb)
132{
133	struct sk_buff *segs;
134
135	if (!skb_is_gso(skb))
136		return xfrm6_output_finish2(skb);
137
138	skb->protocol = htons(ETH_P_IPV6);
139	segs = skb_gso_segment(skb, 0);
140	kfree_skb(skb);
141	if (unlikely(IS_ERR(segs)))
142		return PTR_ERR(segs);
143
144	do {
145		struct sk_buff *nskb = segs->next;
146		int err;
147
148		segs->next = NULL;
149		err = xfrm6_output_finish2(segs);
150
151		if (unlikely(err)) {
152			while ((segs = nskb)) {
153				nskb = segs->next;
154				segs->next = NULL;
155				kfree_skb(segs);
156			}
157			return err;
158		}
159
160		segs = nskb;
161	} while (segs);
162
163	return 0;
164}
165
166int xfrm6_output(struct sk_buff *skb)
167{
168	return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dst->dev,
169		       xfrm6_output_finish);
170}
171