Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * xfrm4_output.c - Common IPsec encapsulation code for IPv4. | |
3 | * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au> | |
e905a9ed | 4 | * |
1da177e4 LT |
5 | * This program is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | */ | |
10 | ||
16a6677f | 11 | #include <linux/compiler.h> |
09b8f7a9 HX |
12 | #include <linux/if_ether.h> |
13 | #include <linux/kernel.h> | |
1da177e4 LT |
14 | #include <linux/skbuff.h> |
15 | #include <linux/spinlock.h> | |
16a6677f | 16 | #include <linux/netfilter_ipv4.h> |
1da177e4 LT |
17 | #include <net/ip.h> |
18 | #include <net/xfrm.h> | |
19 | #include <net/icmp.h> | |
20 | ||
1da177e4 LT |
21 | static int xfrm4_tunnel_check_size(struct sk_buff *skb) |
22 | { | |
23 | int mtu, ret = 0; | |
24 | struct dst_entry *dst; | |
1da177e4 LT |
25 | |
26 | if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) | |
27 | goto out; | |
28 | ||
29 | IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; | |
e905a9ed | 30 | |
eddc9ec5 | 31 | if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df) |
1da177e4 LT |
32 | goto out; |
33 | ||
34 | dst = skb->dst; | |
35 | mtu = dst_mtu(dst); | |
36 | if (skb->len > mtu) { | |
37 | icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); | |
38 | ret = -EMSGSIZE; | |
39 | } | |
40 | out: | |
41 | return ret; | |
42 | } | |
43 | ||
16a6677f | 44 | static int xfrm4_output_one(struct sk_buff *skb) |
1da177e4 LT |
45 | { |
46 | struct dst_entry *dst = skb->dst; | |
47 | struct xfrm_state *x = dst->xfrm; | |
48 | int err; | |
e905a9ed | 49 | |
84fa7933 PM |
50 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
51 | err = skb_checksum_help(skb); | |
1da177e4 LT |
52 | if (err) |
53 | goto error_nolock; | |
54 | } | |
55 | ||
7e49e6de | 56 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
1da177e4 LT |
57 | err = xfrm4_tunnel_check_size(skb); |
58 | if (err) | |
59 | goto error_nolock; | |
60 | } | |
61 | ||
16a6677f PM |
62 | do { |
63 | spin_lock_bh(&x->lock); | |
64 | err = xfrm_state_check(x, skb); | |
65 | if (err) | |
66 | goto error; | |
1da177e4 | 67 | |
eb878e84 | 68 | err = x->mode->output(x, skb); |
b59f45d0 HX |
69 | if (err) |
70 | goto error; | |
1da177e4 | 71 | |
16a6677f PM |
72 | err = x->type->output(x, skb); |
73 | if (err) | |
74 | goto error; | |
1da177e4 | 75 | |
16a6677f PM |
76 | x->curlft.bytes += skb->len; |
77 | x->curlft.packets++; | |
1da177e4 | 78 | |
16a6677f | 79 | spin_unlock_bh(&x->lock); |
e905a9ed | 80 | |
16a6677f PM |
81 | if (!(skb->dst = dst_pop(dst))) { |
82 | err = -EHOSTUNREACH; | |
83 | goto error_nolock; | |
84 | } | |
85 | dst = skb->dst; | |
86 | x = dst->xfrm; | |
7e49e6de | 87 | } while (x && (x->props.mode != XFRM_MODE_TUNNEL)); |
16a6677f | 88 | |
3e3850e9 | 89 | IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; |
16a6677f | 90 | err = 0; |
1da177e4 LT |
91 | |
92 | out_exit: | |
93 | return err; | |
94 | error: | |
95 | spin_unlock_bh(&x->lock); | |
96 | error_nolock: | |
97 | kfree_skb(skb); | |
98 | goto out_exit; | |
99 | } | |
16a6677f | 100 | |
09b8f7a9 | 101 | static int xfrm4_output_finish2(struct sk_buff *skb) |
16a6677f PM |
102 | { |
103 | int err; | |
104 | ||
105 | while (likely((err = xfrm4_output_one(skb)) == 0)) { | |
106 | nf_reset(skb); | |
107 | ||
108 | err = nf_hook(PF_INET, NF_IP_LOCAL_OUT, &skb, NULL, | |
109 | skb->dst->dev, dst_output); | |
110 | if (unlikely(err != 1)) | |
111 | break; | |
112 | ||
113 | if (!skb->dst->xfrm) | |
114 | return dst_output(skb); | |
115 | ||
116 | err = nf_hook(PF_INET, NF_IP_POST_ROUTING, &skb, NULL, | |
09b8f7a9 | 117 | skb->dst->dev, xfrm4_output_finish2); |
16a6677f PM |
118 | if (unlikely(err != 1)) |
119 | break; | |
120 | } | |
121 | ||
122 | return err; | |
123 | } | |
124 | ||
09b8f7a9 HX |
125 | static int xfrm4_output_finish(struct sk_buff *skb) |
126 | { | |
127 | struct sk_buff *segs; | |
128 | ||
129 | #ifdef CONFIG_NETFILTER | |
130 | if (!skb->dst->xfrm) { | |
131 | IPCB(skb)->flags |= IPSKB_REROUTED; | |
132 | return dst_output(skb); | |
133 | } | |
134 | #endif | |
135 | ||
89114afd | 136 | if (!skb_is_gso(skb)) |
09b8f7a9 HX |
137 | return xfrm4_output_finish2(skb); |
138 | ||
139 | skb->protocol = htons(ETH_P_IP); | |
140 | segs = skb_gso_segment(skb, 0); | |
141 | kfree_skb(skb); | |
142 | if (unlikely(IS_ERR(segs))) | |
143 | return PTR_ERR(segs); | |
144 | ||
145 | do { | |
146 | struct sk_buff *nskb = segs->next; | |
147 | int err; | |
148 | ||
149 | segs->next = NULL; | |
150 | err = xfrm4_output_finish2(segs); | |
151 | ||
152 | if (unlikely(err)) { | |
153 | while ((segs = nskb)) { | |
154 | nskb = segs->next; | |
155 | segs->next = NULL; | |
156 | kfree_skb(segs); | |
157 | } | |
158 | return err; | |
159 | } | |
160 | ||
161 | segs = nskb; | |
162 | } while (segs); | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
16a6677f PM |
167 | int xfrm4_output(struct sk_buff *skb) |
168 | { | |
48d5cad8 PM |
169 | return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev, |
170 | xfrm4_output_finish, | |
171 | !(IPCB(skb)->flags & IPSKB_REROUTED)); | |
16a6677f | 172 | } |