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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 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
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_skb_check_space(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
65 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
66 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
67 err = -EINVAL;
68 goto error;
69 }
70
71 err = xfrm_state_check_expire(x);
72 if (err) {
73 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
74 goto error;
75 }
76
77 err = x->repl->overflow(x, skb);
78 if (err) {
79 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
80 goto error;
81 }
82
83 x->curlft.bytes += skb->len;
84 x->curlft.packets++;
85
86 spin_unlock_bh(&x->lock);
87
88 skb_dst_force(skb);
89
90 err = x->type->output(x, skb);
91 if (err == -EINPROGRESS)
92 goto out;
93
94resume:
95 if (err) {
96 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
97 goto error_nolock;
98 }
99
100 dst = skb_dst_pop(skb);
101 if (!dst) {
102 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
103 err = -EHOSTUNREACH;
104 goto error_nolock;
105 }
106 skb_dst_set(skb, dst);
107 x = dst->xfrm;
108 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
109
110 return 0;
111
112error:
113 spin_unlock_bh(&x->lock);
114error_nolock:
115 kfree_skb(skb);
116out:
117 return err;
118}
119
120int xfrm_output_resume(struct sk_buff *skb, int err)
121{
122 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
123 nf_reset(skb);
124
125 err = skb_dst(skb)->ops->local_out(skb);
126 if (unlikely(err != 1))
127 goto out;
128
129 if (!skb_dst(skb)->xfrm)
130 return dst_output(skb);
131
132 err = nf_hook(skb_dst(skb)->ops->family,
133 NF_INET_POST_ROUTING, skb,
134 NULL, skb_dst(skb)->dev, xfrm_output2);
135 if (unlikely(err != 1))
136 goto out;
137 }
138
139 if (err == -EINPROGRESS)
140 err = 0;
141
142out:
143 return err;
144}
145EXPORT_SYMBOL_GPL(xfrm_output_resume);
146
147static int xfrm_output2(struct sk_buff *skb)
148{
149 return xfrm_output_resume(skb, 1);
150}
151
152static int xfrm_output_gso(struct sk_buff *skb)
153{
154 struct sk_buff *segs;
155
156 segs = skb_gso_segment(skb, 0);
157 kfree_skb(skb);
158 if (IS_ERR(segs))
159 return PTR_ERR(segs);
160
161 do {
162 struct sk_buff *nskb = segs->next;
163 int err;
164
165 segs->next = NULL;
166 err = xfrm_output2(segs);
167
168 if (unlikely(err)) {
169 while ((segs = nskb)) {
170 nskb = segs->next;
171 segs->next = NULL;
172 kfree_skb(segs);
173 }
174 return err;
175 }
176
177 segs = nskb;
178 } while (segs);
179
180 return 0;
181}
182
183int xfrm_output(struct sk_buff *skb)
184{
185 struct net *net = dev_net(skb_dst(skb)->dev);
186 int err;
187
188 if (skb_is_gso(skb))
189 return xfrm_output_gso(skb);
190
191 if (skb->ip_summed == CHECKSUM_PARTIAL) {
192 err = skb_checksum_help(skb);
193 if (err) {
194 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
195 kfree_skb(skb);
196 return err;
197 }
198 }
199
200 return xfrm_output2(skb);
201}
202
203int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
204{
205 struct xfrm_mode *inner_mode;
206 if (x->sel.family == AF_UNSPEC)
207 inner_mode = xfrm_ip2inner_mode(x,
208 xfrm_af2proto(skb_dst(skb)->ops->family));
209 else
210 inner_mode = x->inner_mode;
211
212 if (inner_mode == NULL)
213 return -EAFNOSUPPORT;
214 return inner_mode->afinfo->extract_output(x, skb);
215}
216
217void xfrm_local_error(struct sk_buff *skb, int mtu)
218{
219 unsigned int proto;
220 struct xfrm_state_afinfo *afinfo;
221
222 if (skb->protocol == htons(ETH_P_IP))
223 proto = AF_INET;
224 else if (skb->protocol == htons(ETH_P_IPV6))
225 proto = AF_INET6;
226 else
227 return;
228
229 afinfo = xfrm_state_get_afinfo(proto);
230 if (!afinfo)
231 return;
232
233 afinfo->local_error(skb, mtu);
234 xfrm_state_put_afinfo(afinfo);
235}
236
237EXPORT_SYMBOL_GPL(xfrm_output);
238EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
239EXPORT_SYMBOL_GPL(xfrm_local_error);
240
