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;
26 int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
27 - skb_headroom(skb);
28
29 if (nhead > 0)
30 return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC);
31
32 /* Check tail too... */
33 return 0;
34 }
35
36 static int xfrm_output_one(struct sk_buff *skb, int err)
37 {
38 struct dst_entry *dst = skb->dst;
39 struct xfrm_state *x = dst->xfrm;
40
41 if (err <= 0)
42 goto resume;
43
44 do {
45 err = xfrm_state_check_space(x, skb);
46 if (err) {
47 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR);
48 goto error_nolock;
49 }
50
51 err = x->outer_mode->output(x, skb);
52 if (err) {
53 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEMODEERROR);
54 goto error_nolock;
55 }
56
57 spin_lock_bh(&x->lock);
58 err = xfrm_state_check_expire(x);
59 if (err) {
60 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEEXPIRED);
61 goto error;
62 }
63
64 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
65 XFRM_SKB_CB(skb)->seq.output = ++x->replay.oseq;
66 if (unlikely(x->replay.oseq == 0)) {
67 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATESEQERROR);
68 x->replay.oseq--;
69 xfrm_audit_state_replay_overflow(x, skb);
70 err = -EOVERFLOW;
71 goto error;
72 }
73 if (xfrm_aevent_is_on())
74 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
75 }
76
77 x->curlft.bytes += skb->len;
78 x->curlft.packets++;
79
80 spin_unlock_bh(&x->lock);
81
82 err = x->type->output(x, skb);
83 if (err == -EINPROGRESS)
84 goto out_exit;
85
86 resume:
87 if (err) {
88 XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATEPROTOERROR);
89 goto error_nolock;
90 }
91
92 if (!(skb->dst = dst_pop(dst))) {
93 XFRM_INC_STATS(LINUX_MIB_XFRMOUTERROR);
94 err = -EHOSTUNREACH;
95 goto error_nolock;
96 }
97 dst = skb->dst;
98 x = dst->xfrm;
99 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
100
101 err = 0;
102
103 out_exit:
104 return err;
105 error:
106 spin_unlock_bh(&x->lock);
107 error_nolock:
108 kfree_skb(skb);
109 goto out_exit;
110 }
111
112 int xfrm_output_resume(struct sk_buff *skb, int err)
113 {
114 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
115 struct xfrm_state *x;
116
117 nf_reset(skb);
118
119 err = skb->dst->ops->local_out(skb);
120 if (unlikely(err != 1))
121 goto out;
122
123 x = skb->dst->xfrm;
124 if (!x)
125 return dst_output(skb);
126
127 err = nf_hook(skb->dst->ops->family,
128 NF_INET_POST_ROUTING, skb,
129 NULL, skb->dst->dev, xfrm_output2);
130 if (unlikely(err != 1))
131 goto out;
132 }
133
134 if (err == -EINPROGRESS)
135 err = 0;
136
137 out:
138 return err;
139 }
140 EXPORT_SYMBOL_GPL(xfrm_output_resume);
141
142 static int xfrm_output2(struct sk_buff *skb)
143 {
144 return xfrm_output_resume(skb, 1);
145 }
146
147 static int xfrm_output_gso(struct sk_buff *skb)
148 {
149 struct sk_buff *segs;
150
151 segs = skb_gso_segment(skb, 0);
152 kfree_skb(skb);
153 if (unlikely(IS_ERR(segs)))
154 return PTR_ERR(segs);
155
156 do {
157 struct sk_buff *nskb = segs->next;
158 int err;
159
160 segs->next = NULL;
161 err = xfrm_output2(segs);
162
163 if (unlikely(err)) {
164 while ((segs = nskb)) {
165 nskb = segs->next;
166 segs->next = NULL;
167 kfree_skb(segs);
168 }
169 return err;
170 }
171
172 segs = nskb;
173 } while (segs);
174
175 return 0;
176 }
177
178 int xfrm_output(struct sk_buff *skb)
179 {
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(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->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);
213
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