Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6.git] / net / xfrm / xfrm_output.c
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/spinlock.h>
18 #include <net/dst.h>
19 #include <net/xfrm.h>
20
21 static int xfrm_output2(struct sk_buff *skb);
22
23 static 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
40 static 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
91 resume:
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
109 out_exit:
110         return err;
111 error:
112         spin_unlock_bh(&x->lock);
113 error_nolock:
114         kfree_skb(skb);
115         goto out_exit;
116 }
117
118 int 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
140 out:
141         return err;
142 }
143 EXPORT_SYMBOL_GPL(xfrm_output_resume);
144
145 static int xfrm_output2(struct sk_buff *skb)
146 {
147         return xfrm_output_resume(skb, 1);
148 }
149
150 static 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
181 int 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
201 int 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
215 EXPORT_SYMBOL_GPL(xfrm_output);
216 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);