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