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
xfrm_skb_check_space(struct sk_buff * skb)24 static 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
xfrm_output_one(struct sk_buff * skb,int err)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_skb_check_space(skb);
52 if (err) {
53 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
54 goto error_nolock;
55 }
56
57 if (x->props.output_mark)
58 skb->mark = x->props.output_mark;
59
60 err = x->outer_mode->output(x, skb);
61 if (err) {
62 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
63 goto error_nolock;
64 }
65
66 spin_lock_bh(&x->lock);
67
68 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
69 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
70 err = -EINVAL;
71 goto error;
72 }
73
74 err = xfrm_state_check_expire(x);
75 if (err) {
76 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
77 goto error;
78 }
79
80 err = x->repl->overflow(x, skb);
81 if (err) {
82 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
83 goto error;
84 }
85
86 x->curlft.bytes += skb->len;
87 x->curlft.packets++;
88
89 spin_unlock_bh(&x->lock);
90
91 skb_dst_force(skb);
92
93 err = x->type->output(x, skb);
94 if (err == -EINPROGRESS)
95 goto out;
96
97 resume:
98 if (err) {
99 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
100 goto error_nolock;
101 }
102
103 dst = skb_dst_pop(skb);
104 if (!dst) {
105 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
106 err = -EHOSTUNREACH;
107 goto error_nolock;
108 }
109 skb_dst_set(skb, dst);
110 x = dst->xfrm;
111 } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
112
113 return 0;
114
115 error:
116 spin_unlock_bh(&x->lock);
117 error_nolock:
118 kfree_skb(skb);
119 out:
120 return err;
121 }
122
xfrm_output_resume(struct sk_buff * skb,int err)123 int xfrm_output_resume(struct sk_buff *skb, int err)
124 {
125 while (likely((err = xfrm_output_one(skb, err)) == 0)) {
126 nf_reset(skb);
127
128 err = skb_dst(skb)->ops->local_out(skb);
129 if (unlikely(err != 1))
130 goto out;
131
132 if (!skb_dst(skb)->xfrm)
133 return dst_output(skb);
134
135 err = nf_hook(skb_dst(skb)->ops->family,
136 NF_INET_POST_ROUTING, skb,
137 NULL, skb_dst(skb)->dev, xfrm_output2);
138 if (unlikely(err != 1))
139 goto out;
140 }
141
142 if (err == -EINPROGRESS)
143 err = 0;
144
145 out:
146 return err;
147 }
148 EXPORT_SYMBOL_GPL(xfrm_output_resume);
149
xfrm_output2(struct sk_buff * skb)150 static int xfrm_output2(struct sk_buff *skb)
151 {
152 return xfrm_output_resume(skb, 1);
153 }
154
xfrm_output_gso(struct sk_buff * skb)155 static int xfrm_output_gso(struct sk_buff *skb)
156 {
157 struct sk_buff *segs;
158
159 segs = skb_gso_segment(skb, 0);
160 kfree_skb(skb);
161 if (IS_ERR(segs))
162 return PTR_ERR(segs);
163 if (segs == NULL)
164 return -EINVAL;
165
166 do {
167 struct sk_buff *nskb = segs->next;
168 int err;
169
170 segs->next = NULL;
171 err = xfrm_output2(segs);
172
173 if (unlikely(err)) {
174 kfree_skb_list(nskb);
175 return err;
176 }
177
178 segs = nskb;
179 } while (segs);
180
181 return 0;
182 }
183
xfrm_output(struct sk_buff * skb)184 int xfrm_output(struct sk_buff *skb)
185 {
186 struct net *net = dev_net(skb_dst(skb)->dev);
187 int err;
188
189 if (skb_is_gso(skb))
190 return xfrm_output_gso(skb);
191
192 if (skb->ip_summed == CHECKSUM_PARTIAL) {
193 err = skb_checksum_help(skb);
194 if (err) {
195 XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
196 kfree_skb(skb);
197 return err;
198 }
199 }
200
201 return xfrm_output2(skb);
202 }
203 EXPORT_SYMBOL_GPL(xfrm_output);
204
xfrm_inner_extract_output(struct xfrm_state * x,struct sk_buff * skb)205 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
206 {
207 struct xfrm_mode *inner_mode;
208 if (x->sel.family == AF_UNSPEC)
209 inner_mode = xfrm_ip2inner_mode(x,
210 xfrm_af2proto(skb_dst(skb)->ops->family));
211 else
212 inner_mode = x->inner_mode;
213
214 if (inner_mode == NULL)
215 return -EAFNOSUPPORT;
216 return inner_mode->afinfo->extract_output(x, skb);
217 }
218 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
219
xfrm_local_error(struct sk_buff * skb,int mtu)220 void xfrm_local_error(struct sk_buff *skb, int mtu)
221 {
222 unsigned int proto;
223 struct xfrm_state_afinfo *afinfo;
224
225 if (skb->protocol == htons(ETH_P_IP))
226 proto = AF_INET;
227 else if (skb->protocol == htons(ETH_P_IPV6))
228 proto = AF_INET6;
229 else
230 return;
231
232 afinfo = xfrm_state_get_afinfo(proto);
233 if (!afinfo)
234 return;
235
236 afinfo->local_error(skb, mtu);
237 xfrm_state_put_afinfo(afinfo);
238 }
239 EXPORT_SYMBOL_GPL(xfrm_local_error);
240