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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/spinlock.h>
18#include <net/dst.h>
19#include <net/xfrm.h>
20
21static int xfrm_output2(struct sk_buff *skb);
22
23static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
24{
25 struct dst_entry *dst = skb_dst(skb);
26 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
27 - skb_headroom(skb);
28 int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
29
30 if (nhead <= 0) {
31 if (ntail <= 0)
32 return 0;
33 nhead = 0;
34 } else if (ntail < 0)
35 ntail = 0;
36
37 return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
38}
39
40static int xfrm_output_one(struct sk_buff *skb, int err)
41{
42 struct dst_entry *dst = skb_dst(skb);
43 struct xfrm_state *x = dst->xfrm;
44 struct net *net = xs_net(x);
45
46 if (err <= 0)
47 goto resume;
48
49 do {
50 err = xfrm_state_check_space(x, skb);
51 if (err) {
52 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
53 goto error_nolock;
54 }
55
56 err = x->outer_mode->output(x, skb);
57 if (err) {
58 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
59 goto error_nolock;
60 }
61
62 spin_lock_bh(&x->lock);
63 err = xfrm_state_check_expire(x);
64 if (err) {
65 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
66 goto error;
67 }
68
69 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
70 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq;
71 if (unlikely(x->replay.oseq == 0)) {
72 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
73 x->replay.oseq--;
74 xfrm_audit_state_replay_overflow(x, skb);
75 err = -EOVERFLOW;
76 goto error;
77 }
78 if (xfrm_aevent_is_on(net))
79 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
80 }
81
82 x->curlft.bytes += skb->len;
83 x->curlft.packets++;
84
85 spin_unlock_bh(&x->lock);
86
87 err = x->type->output(x, skb);
88 if (err == -EINPROGRESS)
89 goto out_exit;
90
91resume:
92 if (err) {
93 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
94 goto error_nolock;
95 }
96
97 dst = dst_pop(dst);
98 if (!dst) {
99 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
100 err = -EHOSTUNREACH;
101 goto error_nolock;
102 }
103 skb_dst_set(skb, dst);
104 x = dst->xfrm;
105 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
106
107 err = 0;
108
109out_exit:
110 return err;
111error:
112 spin_unlock_bh(&x->lock);
113error_nolock:
114 kfree_skb(skb);
115 goto out_exit;
116}
117
118int xfrm_output_resume(struct sk_buff *skb, int err)
119{
120 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
121 nf_reset(skb);
122
123 err = skb_dst(skb)->ops->local_out(skb);
124 if (unlikely(err != 1))
125 goto out;
126
127 if (!skb_dst(skb)->xfrm)
128 return dst_output(skb);
129
130 err = nf_hook(skb_dst(skb)->ops->family,
131 NF_INET_POST_ROUTING, skb,
132 NULL, skb_dst(skb)->dev, xfrm_output2);
133 if (unlikely(err != 1))
134 goto out;
135 }
136
137 if (err == -EINPROGRESS)
138 err = 0;
139
140out:
141 return err;
142}
143EXPORT_SYMBOL_GPL(xfrm_output_resume);
144
145static int xfrm_output2(struct sk_buff *skb)
146{
147 return xfrm_output_resume(skb, 1);
148}
149
150static int xfrm_output_gso(struct sk_buff *skb)
151{
152 struct sk_buff *segs;
153
154 segs = skb_gso_segment(skb, 0);
155 kfree_skb(skb);
156 if (IS_ERR(segs))
157 return PTR_ERR(segs);
158
159 do {
160 struct sk_buff *nskb = segs->next;
161 int err;
162
163 segs->next = NULL;
164 err = xfrm_output2(segs);
165
166 if (unlikely(err)) {
167 while ((segs = nskb)) {
168 nskb = segs->next;
169 segs->next = NULL;
170 kfree_skb(segs);
171 }
172 return err;
173 }
174
175 segs = nskb;
176 } while (segs);
177
178 return 0;
179}
180
181int xfrm_output(struct sk_buff *skb)
182{
183 struct net *net = dev_net(skb_dst(skb)->dev);
184 int err;
185
186 if (skb_is_gso(skb))
187 return xfrm_output_gso(skb);
188
189 if (skb->ip_summed == CHECKSUM_PARTIAL) {
190 err = skb_checksum_help(skb);
191 if (err) {
192 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
193 kfree_skb(skb);
194 return err;
195 }
196 }
197
198 return xfrm_output2(skb);
199}
200
201int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
202{
203 struct xfrm_mode *inner_mode;
204 if (x->sel.family == AF_UNSPEC)
205 inner_mode = xfrm_ip2inner_mode(x,
206 xfrm_af2proto(skb_dst(skb)->ops->family));
207 else
208 inner_mode = x->inner_mode;
209
210 if (inner_mode == NULL)
211 return -EAFNOSUPPORT;
212 return inner_mode->afinfo->extract_output(x, skb);
213}
214
215EXPORT_SYMBOL_GPL(xfrm_output);
216EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
217
