xfrm: Fix off by one in the replay advance functions
[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/slab.h>
18 #include <linux/spinlock.h>
19 #include <net/dst.h>
20 #include <net/xfrm.h>
21
22 static int xfrm_output2(struct sk_buff *skb);
23
24 static int xfrm_state_check_space(struct xfrm_state *x, 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 static 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_state_check_space(x, 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                 err = xfrm_state_check_expire(x);
65                 if (err) {
66                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
67                         goto error;
68                 }
69
70                 err = x->repl->overflow(x, skb);
71                 if (err) {
72                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
73                         goto error;
74                 }
75
76                 x->curlft.bytes += skb->len;
77                 x->curlft.packets++;
78
79                 spin_unlock_bh(&x->lock);
80
81                 skb_dst_force(skb);
82
83                 err = x->type->output(x, skb);
84                 if (err == -EINPROGRESS)
85                         goto out_exit;
86
87 resume:
88                 if (err) {
89                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
90                         goto error_nolock;
91                 }
92
93                 dst = skb_dst_pop(skb);
94                 if (!dst) {
95                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
96                         err = -EHOSTUNREACH;
97                         goto error_nolock;
98                 }
99                 skb_dst_set(skb, dst);
100                 x = dst->xfrm;
101         } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
102
103         err = 0;
104
105 out_exit:
106         return err;
107 error:
108         spin_unlock_bh(&x->lock);
109 error_nolock:
110         kfree_skb(skb);
111         goto out_exit;
112 }
113
114 int xfrm_output_resume(struct sk_buff *skb, int err)
115 {
116         while (likely((err = xfrm_output_one(skb, err)) == 0)) {
117                 nf_reset(skb);
118
119                 err = skb_dst(skb)->ops->local_out(skb);
120                 if (unlikely(err != 1))
121                         goto out;
122
123                 if (!skb_dst(skb)->xfrm)
124                         return dst_output(skb);
125
126                 err = nf_hook(skb_dst(skb)->ops->family,
127                               NF_INET_POST_ROUTING, skb,
128                               NULL, skb_dst(skb)->dev, xfrm_output2);
129                 if (unlikely(err != 1))
130                         goto out;
131         }
132
133         if (err == -EINPROGRESS)
134                 err = 0;
135
136 out:
137         return err;
138 }
139 EXPORT_SYMBOL_GPL(xfrm_output_resume);
140
141 static int xfrm_output2(struct sk_buff *skb)
142 {
143         return xfrm_output_resume(skb, 1);
144 }
145
146 static int xfrm_output_gso(struct sk_buff *skb)
147 {
148         struct sk_buff *segs;
149
150         segs = skb_gso_segment(skb, 0);
151         kfree_skb(skb);
152         if (IS_ERR(segs))
153                 return PTR_ERR(segs);
154
155         do {
156                 struct sk_buff *nskb = segs->next;
157                 int err;
158
159                 segs->next = NULL;
160                 err = xfrm_output2(segs);
161
162                 if (unlikely(err)) {
163                         while ((segs = nskb)) {
164                                 nskb = segs->next;
165                                 segs->next = NULL;
166                                 kfree_skb(segs);
167                         }
168                         return err;
169                 }
170
171                 segs = nskb;
172         } while (segs);
173
174         return 0;
175 }
176
177 int xfrm_output(struct sk_buff *skb)
178 {
179         struct net *net = dev_net(skb_dst(skb)->dev);
180         int err;
181
182         if (skb_is_gso(skb))
183                 return xfrm_output_gso(skb);
184
185         if (skb->ip_summed == CHECKSUM_PARTIAL) {
186                 err = skb_checksum_help(skb);
187                 if (err) {
188                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
189                         kfree_skb(skb);
190                         return err;
191                 }
192         }
193
194         return xfrm_output2(skb);
195 }
196
197 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
198 {
199         struct xfrm_mode *inner_mode;
200         if (x->sel.family == AF_UNSPEC)
201                 inner_mode = xfrm_ip2inner_mode(x,
202                                 xfrm_af2proto(skb_dst(skb)->ops->family));
203         else
204                 inner_mode = x->inner_mode;
205
206         if (inner_mode == NULL)
207                 return -EAFNOSUPPORT;
208         return inner_mode->afinfo->extract_output(x, skb);
209 }
210
211 EXPORT_SYMBOL_GPL(xfrm_output);
212 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);