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Merge tag 'for-linus-4.12b-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel...
[karo-tx-linux.git] / net / ipv4 / xfrm4_mode_transport.c
1 /*
2  * xfrm4_mode_transport.c - Transport mode encapsulation for IPv4.
3  *
4  * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
5  */
6
7 #include <linux/init.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/skbuff.h>
11 #include <linux/stringify.h>
12 #include <net/dst.h>
13 #include <net/ip.h>
14 #include <net/xfrm.h>
15 #include <net/protocol.h>
16
17 /* Add encapsulation header.
18  *
19  * The IP header will be moved forward to make space for the encapsulation
20  * header.
21  */
22 static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
23 {
24         struct iphdr *iph = ip_hdr(skb);
25         int ihl = iph->ihl * 4;
26
27         skb_set_inner_transport_header(skb, skb_transport_offset(skb));
28
29         skb_set_network_header(skb, -x->props.header_len);
30         skb->mac_header = skb->network_header +
31                           offsetof(struct iphdr, protocol);
32         skb->transport_header = skb->network_header + ihl;
33         __skb_pull(skb, ihl);
34         memmove(skb_network_header(skb), iph, ihl);
35         return 0;
36 }
37
38 /* Remove encapsulation header.
39  *
40  * The IP header will be moved over the top of the encapsulation header.
41  *
42  * On entry, skb->h shall point to where the IP header should be and skb->nh
43  * shall be set to where the IP header currently is.  skb->data shall point
44  * to the start of the payload.
45  */
46 static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
47 {
48         int ihl = skb->data - skb_transport_header(skb);
49         struct xfrm_offload *xo = xfrm_offload(skb);
50
51         if (skb->transport_header != skb->network_header) {
52                 memmove(skb_transport_header(skb),
53                         skb_network_header(skb), ihl);
54                 skb->network_header = skb->transport_header;
55         }
56         ip_hdr(skb)->tot_len = htons(skb->len + ihl);
57         if (!xo || !(xo->flags & XFRM_GRO))
58                 skb_reset_transport_header(skb);
59         return 0;
60 }
61
62 static struct sk_buff *xfrm4_transport_gso_segment(struct xfrm_state *x,
63                                                    struct sk_buff *skb,
64                                                    netdev_features_t features)
65 {
66         const struct net_offload *ops;
67         struct sk_buff *segs = ERR_PTR(-EINVAL);
68         struct xfrm_offload *xo = xfrm_offload(skb);
69
70         skb->transport_header += x->props.header_len;
71         ops = rcu_dereference(inet_offloads[xo->proto]);
72         if (likely(ops && ops->callbacks.gso_segment))
73                 segs = ops->callbacks.gso_segment(skb, features);
74
75         return segs;
76 }
77
78 static void xfrm4_transport_xmit(struct xfrm_state *x, struct sk_buff *skb)
79 {
80         struct xfrm_offload *xo = xfrm_offload(skb);
81
82         skb_reset_mac_len(skb);
83         pskb_pull(skb, skb->mac_len + sizeof(struct iphdr) + x->props.header_len);
84
85         if (xo->flags & XFRM_GSO_SEGMENT) {
86                  skb_reset_transport_header(skb);
87                  skb->transport_header -= x->props.header_len;
88         }
89 }
90
91 static struct xfrm_mode xfrm4_transport_mode = {
92         .input = xfrm4_transport_input,
93         .output = xfrm4_transport_output,
94         .gso_segment = xfrm4_transport_gso_segment,
95         .xmit = xfrm4_transport_xmit,
96         .owner = THIS_MODULE,
97         .encap = XFRM_MODE_TRANSPORT,
98 };
99
100 static int __init xfrm4_transport_init(void)
101 {
102         return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
103 }
104
105 static void __exit xfrm4_transport_exit(void)
106 {
107         int err;
108
109         err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
110         BUG_ON(err);
111 }
112
113 module_init(xfrm4_transport_init);
114 module_exit(xfrm4_transport_exit);
115 MODULE_LICENSE("GPL");
116 MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);