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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
42
43
44
45static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
46{
47 struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
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 skb->mark = xfrm_smark_get(skb->mark, x);
70
71 err = x->outer_mode->output(x, skb);
72 if (err) {
73 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
74 goto error_nolock;
75 }
76
77 spin_lock_bh(&x->lock);
78
79 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
80 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
81 err = -EINVAL;
82 goto error;
83 }
84
85 err = xfrm_state_check_expire(x);
86 if (err) {
87 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
88 goto error;
89 }
90
91 err = x->repl->overflow(x, skb);
92 if (err) {
93 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
94 goto error;
95 }
96
97 x->curlft.bytes += skb->len;
98 x->curlft.packets++;
99
100 spin_unlock_bh(&x->lock);
101
102 skb_dst_force(skb);
103 if (!skb_dst(skb)) {
104 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
105 goto error_nolock;
106 }
107
108 if (xfrm_offload(skb)) {
109 x->type_offload->encap(x, skb);
110 } else {
111
112 skb->encapsulation = 0;
113
114 err = x->type->output(x, skb);
115 if (err == -EINPROGRESS)
116 goto out;
117 }
118
119resume:
120 if (err) {
121 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
122 goto error_nolock;
123 }
124
125 dst = skb_dst_pop(skb);
126 if (!dst) {
127 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
128 err = -EHOSTUNREACH;
129 goto error_nolock;
130 }
131 skb_dst_set(skb, dst);
132 x = dst->xfrm;
133 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
134
135 return 0;
136
137error:
138 spin_unlock_bh(&x->lock);
139error_nolock:
140 kfree_skb(skb);
141out:
142 return err;
143}
144
145int xfrm_output_resume(struct sk_buff *skb, int err)
146{
147 struct net *net = xs_net(skb_dst(skb)->xfrm);
148
149 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
150 nf_reset(skb);
151
152 err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
153 if (unlikely(err != 1))
154 goto out;
155
156 if (!skb_dst(skb)->xfrm)
157 return dst_output(net, skb->sk, skb);
158
159 err = nf_hook(skb_dst(skb)->ops->family,
160 NF_INET_POST_ROUTING, net, skb->sk, skb,
161 NULL, skb_dst(skb)->dev, xfrm_output2);
162 if (unlikely(err != 1))
163 goto out;
164 }
165
166 if (err == -EINPROGRESS)
167 err = 0;
168
169out:
170 return err;
171}
172EXPORT_SYMBOL_GPL(xfrm_output_resume);
173
174static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
175{
176 return xfrm_output_resume(skb, 1);
177}
178
179static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
180{
181 struct sk_buff *segs;
182
183 BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
184 BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_SGO_CB_OFFSET);
185 segs = skb_gso_segment(skb, 0);
186 kfree_skb(skb);
187 if (IS_ERR(segs))
188 return PTR_ERR(segs);
189 if (segs == NULL)
190 return -EINVAL;
191
192 do {
193 struct sk_buff *nskb = segs->next;
194 int err;
195
196 segs->next = NULL;
197 err = xfrm_output2(net, sk, segs);
198
199 if (unlikely(err)) {
200 kfree_skb_list(nskb);
201 return err;
202 }
203
204 segs = nskb;
205 } while (segs);
206
207 return 0;
208}
209
210int xfrm_output(struct sock *sk, struct sk_buff *skb)
211{
212 struct net *net = dev_net(skb_dst(skb)->dev);
213 struct xfrm_state *x = skb_dst(skb)->xfrm;
214 int err;
215
216 secpath_reset(skb);
217
218 if (xfrm_dev_offload_ok(skb, x)) {
219 struct sec_path *sp;
220
221 sp = secpath_dup(skb->sp);
222 if (!sp) {
223 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
224 kfree_skb(skb);
225 return -ENOMEM;
226 }
227 if (skb->sp)
228 secpath_put(skb->sp);
229 skb->sp = sp;
230 skb->encapsulation = 1;
231
232 sp->olen++;
233 sp->xvec[skb->sp->len++] = x;
234 xfrm_state_hold(x);
235
236 if (skb_is_gso(skb)) {
237 skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
238
239 return xfrm_output2(net, sk, skb);
240 }
241
242 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
243 goto out;
244 }
245
246 if (skb_is_gso(skb))
247 return xfrm_output_gso(net, sk, skb);
248
249 if (skb->ip_summed == CHECKSUM_PARTIAL) {
250 err = skb_checksum_help(skb);
251 if (err) {
252 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
253 kfree_skb(skb);
254 return err;
255 }
256 }
257
258out:
259 return xfrm_output2(net, sk, skb);
260}
261EXPORT_SYMBOL_GPL(xfrm_output);
262
263int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
264{
265 struct xfrm_mode *inner_mode;
266 if (x->sel.family == AF_UNSPEC)
267 inner_mode = xfrm_ip2inner_mode(x,
268 xfrm_af2proto(skb_dst(skb)->ops->family));
269 else
270 inner_mode = x->inner_mode;
271
272 if (inner_mode == NULL)
273 return -EAFNOSUPPORT;
274 return inner_mode->afinfo->extract_output(x, skb);
275}
276EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
277
278void xfrm_local_error(struct sk_buff *skb, int mtu)
279{
280 unsigned int proto;
281 struct xfrm_state_afinfo *afinfo;
282
283 if (skb->protocol == htons(ETH_P_IP))
284 proto = AF_INET;
285 else if (skb->protocol == htons(ETH_P_IPV6))
286 proto = AF_INET6;
287 else
288 return;
289
290 afinfo = xfrm_state_get_afinfo(proto);
291 if (afinfo) {
292 afinfo->local_error(skb, mtu);
293 rcu_read_unlock();
294 }
295}
296EXPORT_SYMBOL_GPL(xfrm_local_error);
297
