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1/*
2 * xfrm_output.c - Common IPsec encapsulation code.
3 *
4 * Copyright (c) 2007 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/errno.h>
13#include <linux/module.h>
14#include <linux/netdevice.h>
15#include <linux/netfilter.h>
16#include <linux/skbuff.h>
17#include <linux/slab.h>
18#include <linux/spinlock.h>
19#include <net/dst.h>
20#include <net/xfrm.h>
21
22static int xfrm_output2(struct sk_buff *skb);
23
24static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
25{
26 struct dst_entry *dst = skb_dst(skb);
27 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
28 - skb_headroom(skb);
29 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
30
31 if (nhead <= 0) {
32 if (ntail <= 0)
33 return 0;
34 nhead = 0;
35 } else if (ntail < 0)
36 ntail = 0;
37
38 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
39}
40
41static int xfrm_output_one(struct sk_buff *skb, int err)
42{
43 struct dst_entry *dst = skb_dst(skb);
44 struct xfrm_state *x = dst->xfrm;
45 struct net *net = xs_net(x);
46
47 if (err <= 0)
48 goto resume;
49
50 do {
51 err = xfrm_state_check_space(x, skb);
52 if (err) {
53 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
54 goto error_nolock;
55 }
56
57 err = x->outer_mode->output(x, skb);
58 if (err) {
59 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
60 goto error_nolock;
61 }
62
63 spin_lock_bh(&x->lock);
64 err = xfrm_state_check_expire(x);
65 if (err) {
66 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
67 goto error;
68 }
69
70 err = x->repl->overflow(x, skb);
71 if (err) {
72 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
73 goto error;
74 }
75
76 x->curlft.bytes += skb->len;
77 x->curlft.packets++;
78
79 spin_unlock_bh(&x->lock);
80
81 skb_dst_force(skb);
82
83 err = x->type->output(x, skb);
84 if (err == -EINPROGRESS)
85 goto out_exit;
86
87resume:
88 if (err) {
89 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
90 goto error_nolock;
91 }
92
93 dst = skb_dst_pop(skb);
94 if (!dst) {
95 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
96 err = -EHOSTUNREACH;
97 goto error_nolock;
98 }
99 skb_dst_set(skb, dst);
100 x = dst->xfrm;
101 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
102
103 err = 0;
104
105out_exit:
106 return err;
107error:
108 spin_unlock_bh(&x->lock);
109error_nolock:
110 kfree_skb(skb);
111 goto out_exit;
112}
113
114int xfrm_output_resume(struct sk_buff *skb, int err)
115{
116 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
117 nf_reset(skb);
118
119 err = skb_dst(skb)->ops->local_out(skb);
120 if (unlikely(err != 1))
121 goto out;
122
123 if (!skb_dst(skb)->xfrm)
124 return dst_output(skb);
125
126 err = nf_hook(skb_dst(skb)->ops->family,
127 NF_INET_POST_ROUTING, skb,
128 NULL, skb_dst(skb)->dev, xfrm_output2);
129 if (unlikely(err != 1))
130 goto out;
131 }
132
133 if (err == -EINPROGRESS)
134 err = 0;
135
136out:
137 return err;
138}
139EXPORT_SYMBOL_GPL(xfrm_output_resume);
140
141static int xfrm_output2(struct sk_buff *skb)
142{
143 return xfrm_output_resume(skb, 1);
144}
145
146static int xfrm_output_gso(struct sk_buff *skb)
147{
148 struct sk_buff *segs;
149
150 segs = skb_gso_segment(skb, 0);
151 kfree_skb(skb);
152 if (IS_ERR(segs))
153 return PTR_ERR(segs);
154
155 do {
156 struct sk_buff *nskb = segs->next;
157 int err;
158
159 segs->next = NULL;
160 err = xfrm_output2(segs);
161
162 if (unlikely(err)) {
163 while ((segs = nskb)) {
164 nskb = segs->next;
165 segs->next = NULL;
166 kfree_skb(segs);
167 }
168 return err;
169 }
170
171 segs = nskb;
172 } while (segs);
173
174 return 0;
175}
176
177int xfrm_output(struct sk_buff *skb)
178{
179 struct net *net = dev_net(skb_dst(skb)->dev);
180 int err;
181
182 if (skb_is_gso(skb))
183 return xfrm_output_gso(skb);
184
185 if (skb->ip_summed == CHECKSUM_PARTIAL) {
186 err = skb_checksum_help(skb);
187 if (err) {
188 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
189 kfree_skb(skb);
190 return err;
191 }
192 }
193
194 return xfrm_output2(skb);
195}
196
197int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
198{
199 struct xfrm_mode *inner_mode;
200 if (x->sel.family == AF_UNSPEC)
201 inner_mode = xfrm_ip2inner_mode(x,
202 xfrm_af2proto(skb_dst(skb)->ops->family));
203 else
204 inner_mode = x->inner_mode;
205
206 if (inner_mode == NULL)
207 return -EAFNOSUPPORT;
208 return inner_mode->afinfo->extract_output(x, skb);
209}
210
211EXPORT_SYMBOL_GPL(xfrm_output);
212EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
1/*
2 * xfrm_output.c - Common IPsec encapsulation code.
3 *
4 * Copyright (c) 2007 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/errno.h>
13#include <linux/module.h>
14#include <linux/netdevice.h>
15#include <linux/netfilter.h>
16#include <linux/skbuff.h>
17#include <linux/slab.h>
18#include <linux/spinlock.h>
19#include <net/dst.h>
20#include <net/xfrm.h>
21
22static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
23
24static int xfrm_skb_check_space(struct sk_buff *skb)
25{
26 struct dst_entry *dst = skb_dst(skb);
27 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
28 - skb_headroom(skb);
29 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
30
31 if (nhead <= 0) {
32 if (ntail <= 0)
33 return 0;
34 nhead = 0;
35 } else if (ntail < 0)
36 ntail = 0;
37
38 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
39}
40
41/* Children define the path of the packet through the
42 * Linux networking. Thus, destinations are stackable.
43 */
44
45static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
46{
47 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
48
49 skb_dst_drop(skb);
50 return child;
51}
52
53static int xfrm_output_one(struct sk_buff *skb, int err)
54{
55 struct dst_entry *dst = skb_dst(skb);
56 struct xfrm_state *x = dst->xfrm;
57 struct net *net = xs_net(x);
58
59 if (err <= 0)
60 goto resume;
61
62 do {
63 err = xfrm_skb_check_space(skb);
64 if (err) {
65 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
66 goto error_nolock;
67 }
68
69 err = x->outer_mode->output(x, skb);
70 if (err) {
71 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
72 goto error_nolock;
73 }
74
75 spin_lock_bh(&x->lock);
76
77 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
78 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
79 err = -EINVAL;
80 goto error;
81 }
82
83 err = xfrm_state_check_expire(x);
84 if (err) {
85 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
86 goto error;
87 }
88
89 err = x->repl->overflow(x, skb);
90 if (err) {
91 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
92 goto error;
93 }
94
95 x->curlft.bytes += skb->len;
96 x->curlft.packets++;
97
98 spin_unlock_bh(&x->lock);
99
100 skb_dst_force(skb);
101
102 /* Inner headers are invalid now. */
103 skb->encapsulation = 0;
104
105 err = x->type->output(x, skb);
106 if (err == -EINPROGRESS)
107 goto out;
108
109resume:
110 if (err) {
111 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
112 goto error_nolock;
113 }
114
115 dst = skb_dst_pop(skb);
116 if (!dst) {
117 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
118 err = -EHOSTUNREACH;
119 goto error_nolock;
120 }
121 skb_dst_set(skb, dst);
122 x = dst->xfrm;
123 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
124
125 return 0;
126
127error:
128 spin_unlock_bh(&x->lock);
129error_nolock:
130 kfree_skb(skb);
131out:
132 return err;
133}
134
135int xfrm_output_resume(struct sk_buff *skb, int err)
136{
137 struct net *net = xs_net(skb_dst(skb)->xfrm);
138
139 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
140 nf_reset(skb);
141
142 err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
143 if (unlikely(err != 1))
144 goto out;
145
146 if (!skb_dst(skb)->xfrm)
147 return dst_output(net, skb->sk, skb);
148
149 err = nf_hook(skb_dst(skb)->ops->family,
150 NF_INET_POST_ROUTING, net, skb->sk, skb,
151 NULL, skb_dst(skb)->dev, xfrm_output2);
152 if (unlikely(err != 1))
153 goto out;
154 }
155
156 if (err == -EINPROGRESS)
157 err = 0;
158
159out:
160 return err;
161}
162EXPORT_SYMBOL_GPL(xfrm_output_resume);
163
164static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
165{
166 return xfrm_output_resume(skb, 1);
167}
168
169static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
170{
171 struct sk_buff *segs;
172
173 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
174 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_SGO_CB_OFFSET);
175 segs = skb_gso_segment(skb, 0);
176 kfree_skb(skb);
177 if (IS_ERR(segs))
178 return PTR_ERR(segs);
179 if (segs == NULL)
180 return -EINVAL;
181
182 do {
183 struct sk_buff *nskb = segs->next;
184 int err;
185
186 segs->next = NULL;
187 err = xfrm_output2(net, sk, segs);
188
189 if (unlikely(err)) {
190 kfree_skb_list(nskb);
191 return err;
192 }
193
194 segs = nskb;
195 } while (segs);
196
197 return 0;
198}
199
200int xfrm_output(struct sock *sk, struct sk_buff *skb)
201{
202 struct net *net = dev_net(skb_dst(skb)->dev);
203 int err;
204
205 if (skb_is_gso(skb))
206 return xfrm_output_gso(net, sk, skb);
207
208 if (skb->ip_summed == CHECKSUM_PARTIAL) {
209 err = skb_checksum_help(skb);
210 if (err) {
211 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
212 kfree_skb(skb);
213 return err;
214 }
215 }
216
217 return xfrm_output2(net, sk, skb);
218}
219EXPORT_SYMBOL_GPL(xfrm_output);
220
221int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
222{
223 struct xfrm_mode *inner_mode;
224 if (x->sel.family == AF_UNSPEC)
225 inner_mode = xfrm_ip2inner_mode(x,
226 xfrm_af2proto(skb_dst(skb)->ops->family));
227 else
228 inner_mode = x->inner_mode;
229
230 if (inner_mode == NULL)
231 return -EAFNOSUPPORT;
232 return inner_mode->afinfo->extract_output(x, skb);
233}
234EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
235
236void xfrm_local_error(struct sk_buff *skb, int mtu)
237{
238 unsigned int proto;
239 struct xfrm_state_afinfo *afinfo;
240
241 if (skb->protocol == htons(ETH_P_IP))
242 proto = AF_INET;
243 else if (skb->protocol == htons(ETH_P_IPV6))
244 proto = AF_INET6;
245 else
246 return;
247
248 afinfo = xfrm_state_get_afinfo(proto);
249 if (!afinfo)
250 return;
251
252 afinfo->local_error(skb, mtu);
253 xfrm_state_put_afinfo(afinfo);
254}
255EXPORT_SYMBOL_GPL(xfrm_local_error);