Merge branch 'stable/for-jens-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git...
[platform/kernel/linux-starfive.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 net *net, struct sock *sk, struct sk_buff *skb);
23
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
41 /* Children define the path of the packet through the
42  * Linux networking.  Thus, destinations are stackable.
43  */
44
45 static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
46 {
47         struct dst_entry *child = dst_clone(skb_dst(skb)->child);
48
49         skb_dst_drop(skb);
50         return child;
51 }
52
53 static int xfrm_output_one(struct sk_buff *skb, int err)
54 {
55         struct dst_entry *dst = skb_dst(skb);
56         struct xfrm_state *x = dst->xfrm;
57         struct net *net = xs_net(x);
58
59         if (err <= 0)
60                 goto resume;
61
62         do {
63                 err = xfrm_skb_check_space(skb);
64                 if (err) {
65                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
66                         goto error_nolock;
67                 }
68
69                 err = x->outer_mode->output(x, skb);
70                 if (err) {
71                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
72                         goto error_nolock;
73                 }
74
75                 spin_lock_bh(&x->lock);
76
77                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
78                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
79                         err = -EINVAL;
80                         goto error;
81                 }
82
83                 err = xfrm_state_check_expire(x);
84                 if (err) {
85                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
86                         goto error;
87                 }
88
89                 err = x->repl->overflow(x, skb);
90                 if (err) {
91                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
92                         goto error;
93                 }
94
95                 x->curlft.bytes += skb->len;
96                 x->curlft.packets++;
97
98                 spin_unlock_bh(&x->lock);
99
100                 skb_dst_force(skb);
101
102                 /* Inner headers are invalid now. */
103                 skb->encapsulation = 0;
104
105                 err = x->type->output(x, skb);
106                 if (err == -EINPROGRESS)
107                         goto out;
108
109 resume:
110                 if (err) {
111                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
112                         goto error_nolock;
113                 }
114
115                 dst = skb_dst_pop(skb);
116                 if (!dst) {
117                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
118                         err = -EHOSTUNREACH;
119                         goto error_nolock;
120                 }
121                 skb_dst_set(skb, dst);
122                 x = dst->xfrm;
123         } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
124
125         return 0;
126
127 error:
128         spin_unlock_bh(&x->lock);
129 error_nolock:
130         kfree_skb(skb);
131 out:
132         return err;
133 }
134
135 int xfrm_output_resume(struct sk_buff *skb, int err)
136 {
137         struct net *net = xs_net(skb_dst(skb)->xfrm);
138
139         while (likely((err = xfrm_output_one(skb, err)) == 0)) {
140                 nf_reset(skb);
141
142                 err = skb_dst(skb)->ops->local_out(net, skb->sk, skb);
143                 if (unlikely(err != 1))
144                         goto out;
145
146                 if (!skb_dst(skb)->xfrm)
147                         return dst_output(net, skb->sk, skb);
148
149                 err = nf_hook(skb_dst(skb)->ops->family,
150                               NF_INET_POST_ROUTING, net, skb->sk, skb,
151                               NULL, skb_dst(skb)->dev, xfrm_output2);
152                 if (unlikely(err != 1))
153                         goto out;
154         }
155
156         if (err == -EINPROGRESS)
157                 err = 0;
158
159 out:
160         return err;
161 }
162 EXPORT_SYMBOL_GPL(xfrm_output_resume);
163
164 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
165 {
166         return xfrm_output_resume(skb, 1);
167 }
168
169 static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
170 {
171         struct sk_buff *segs;
172
173         BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_SGO_CB_OFFSET);
174         BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_SGO_CB_OFFSET);
175         segs = skb_gso_segment(skb, 0);
176         kfree_skb(skb);
177         if (IS_ERR(segs))
178                 return PTR_ERR(segs);
179         if (segs == NULL)
180                 return -EINVAL;
181
182         do {
183                 struct sk_buff *nskb = segs->next;
184                 int err;
185
186                 segs->next = NULL;
187                 err = xfrm_output2(net, sk, segs);
188
189                 if (unlikely(err)) {
190                         kfree_skb_list(nskb);
191                         return err;
192                 }
193
194                 segs = nskb;
195         } while (segs);
196
197         return 0;
198 }
199
200 int xfrm_output(struct sock *sk, struct sk_buff *skb)
201 {
202         struct net *net = dev_net(skb_dst(skb)->dev);
203         int err;
204
205         if (skb_is_gso(skb))
206                 return xfrm_output_gso(net, sk, skb);
207
208         if (skb->ip_summed == CHECKSUM_PARTIAL) {
209                 err = skb_checksum_help(skb);
210                 if (err) {
211                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
212                         kfree_skb(skb);
213                         return err;
214                 }
215         }
216
217         return xfrm_output2(net, sk, skb);
218 }
219 EXPORT_SYMBOL_GPL(xfrm_output);
220
221 int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
222 {
223         struct xfrm_mode *inner_mode;
224         if (x->sel.family == AF_UNSPEC)
225                 inner_mode = xfrm_ip2inner_mode(x,
226                                 xfrm_af2proto(skb_dst(skb)->ops->family));
227         else
228                 inner_mode = x->inner_mode;
229
230         if (inner_mode == NULL)
231                 return -EAFNOSUPPORT;
232         return inner_mode->afinfo->extract_output(x, skb);
233 }
234 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
235
236 void xfrm_local_error(struct sk_buff *skb, int mtu)
237 {
238         unsigned int proto;
239         struct xfrm_state_afinfo *afinfo;
240
241         if (skb->protocol == htons(ETH_P_IP))
242                 proto = AF_INET;
243         else if (skb->protocol == htons(ETH_P_IPV6))
244                 proto = AF_INET6;
245         else
246                 return;
247
248         afinfo = xfrm_state_get_afinfo(proto);
249         if (!afinfo)
250                 return;
251
252         afinfo->local_error(skb, mtu);
253         xfrm_state_put_afinfo(afinfo);
254 }
255 EXPORT_SYMBOL_GPL(xfrm_local_error);