tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/if_ether.h>
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/skbuff.h>
16#include <linux/icmpv6.h>
17#include <linux/netfilter_ipv6.h>
18#include <net/dst.h>
19#include <net/ipv6.h>
20#include <net/ip6_route.h>
21#include <net/xfrm.h>
22
23int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
24 u8 **prevhdr)
25{
26 return ip6_find_1stfragopt(skb, prevhdr);
27}
28EXPORT_SYMBOL(xfrm6_find_1stfragopt);
29
30static int xfrm6_local_dontfrag(struct sk_buff *skb)
31{
32 int proto;
33 struct sock *sk = skb->sk;
34
35 if (sk) {
36 if (sk->sk_family != AF_INET6)
37 return 0;
38
39 proto = sk->sk_protocol;
40 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
41 return inet6_sk(sk)->dontfrag;
42 }
43
44 return 0;
45}
46
47static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
48{
49 struct flowi6 fl6;
50 struct sock *sk = skb->sk;
51
52 fl6.flowi6_oif = sk->sk_bound_dev_if;
53 fl6.daddr = ipv6_hdr(skb)->daddr;
54
55 ipv6_local_rxpmtu(sk, &fl6, mtu);
56}
57
58void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
59{
60 struct flowi6 fl6;
61 const struct ipv6hdr *hdr;
62 struct sock *sk = skb->sk;
63
64 hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
65 fl6.fl6_dport = inet_sk(sk)->inet_dport;
66 fl6.daddr = hdr->daddr;
67
68 ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
69}
70
71static int xfrm6_tunnel_check_size(struct sk_buff *skb)
72{
73 int mtu, ret = 0;
74 struct dst_entry *dst = skb_dst(skb);
75
76 if (skb->ignore_df)
77 goto out;
78
79 mtu = dst_mtu(dst);
80 if (mtu < IPV6_MIN_MTU)
81 mtu = IPV6_MIN_MTU;
82
83 if ((!skb_is_gso(skb) && skb->len > mtu) ||
84 (skb_is_gso(skb) &&
85 !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
86 skb->dev = dst->dev;
87 skb->protocol = htons(ETH_P_IPV6);
88
89 if (xfrm6_local_dontfrag(skb))
90 xfrm6_local_rxpmtu(skb, mtu);
91 else if (skb->sk)
92 xfrm_local_error(skb, mtu);
93 else
94 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
95 ret = -EMSGSIZE;
96 }
97out:
98 return ret;
99}
100
101int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
102{
103 int err;
104
105 err = xfrm6_tunnel_check_size(skb);
106 if (err)
107 return err;
108
109 XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
110
111 return xfrm6_extract_header(skb);
112}
113
114int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
115{
116 int err;
117
118 err = xfrm_inner_extract_output(x, skb);
119 if (err)
120 return err;
121
122 skb->ignore_df = 1;
123 skb->protocol = htons(ETH_P_IPV6);
124
125 return x->outer_mode->output2(x, skb);
126}
127EXPORT_SYMBOL(xfrm6_prepare_output);
128
129int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
130{
131 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
132
133#ifdef CONFIG_NETFILTER
134 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
135#endif
136
137 return xfrm_output(sk, skb);
138}
139
140static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
141{
142 struct xfrm_state *x = skb_dst(skb)->xfrm;
143
144 return x->outer_mode->afinfo->output_finish(sk, skb);
145}
146
147static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
148{
149 struct dst_entry *dst = skb_dst(skb);
150 struct xfrm_state *x = dst->xfrm;
151 int mtu;
152 bool toobig;
153
154#ifdef CONFIG_NETFILTER
155 if (!x) {
156 IP6CB(skb)->flags |= IP6SKB_REROUTED;
157 return dst_output(net, sk, skb);
158 }
159#endif
160
161 if (x->props.mode != XFRM_MODE_TUNNEL)
162 goto skip_frag;
163
164 if (skb->protocol == htons(ETH_P_IPV6))
165 mtu = ip6_skb_dst_mtu(skb);
166 else
167 mtu = dst_mtu(skb_dst(skb));
168
169 toobig = skb->len > mtu && !skb_is_gso(skb);
170
171 if (toobig && xfrm6_local_dontfrag(skb)) {
172 xfrm6_local_rxpmtu(skb, mtu);
173 kfree_skb(skb);
174 return -EMSGSIZE;
175 } else if (!skb->ignore_df && toobig && skb->sk) {
176 xfrm_local_error(skb, mtu);
177 kfree_skb(skb);
178 return -EMSGSIZE;
179 }
180
181 if (toobig || dst_allfrag(skb_dst(skb)))
182 return ip6_fragment(net, sk, skb,
183 __xfrm6_output_finish);
184
185skip_frag:
186 return x->outer_mode->afinfo->output_finish(sk, skb);
187}
188
189int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
190{
191 return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
192 net, sk, skb, NULL, skb_dst(skb)->dev,
193 __xfrm6_output,
194 !(IP6CB(skb)->flags & IP6SKB_REROUTED));
195}