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Commit | Line | Data |
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b59f45d0 HX |
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> | |
c35fe410 | 15 | #include <net/protocol.h> |
b59f45d0 HX |
16 | |
17 | /* Add encapsulation header. | |
18 | * | |
19 | * The IP header will be moved forward to make space for the encapsulation | |
20 | * header. | |
b59f45d0 | 21 | */ |
eb878e84 | 22 | static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb) |
b59f45d0 | 23 | { |
eddc9ec5 ACM |
24 | struct iphdr *iph = ip_hdr(skb); |
25 | int ihl = iph->ihl * 4; | |
b59f45d0 | 26 | |
f1bd7d65 IT |
27 | skb_set_inner_transport_header(skb, skb_transport_offset(skb)); |
28 | ||
7b277b1a | 29 | skb_set_network_header(skb, -x->props.header_len); |
37fedd3a HX |
30 | skb->mac_header = skb->network_header + |
31 | offsetof(struct iphdr, protocol); | |
32 | skb->transport_header = skb->network_header + ihl; | |
7b277b1a | 33 | __skb_pull(skb, ihl); |
d56f90a7 | 34 | memmove(skb_network_header(skb), iph, ihl); |
b59f45d0 HX |
35 | return 0; |
36 | } | |
37 | ||
31a4ab93 HX |
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 | */ | |
b59f45d0 HX |
46 | static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb) |
47 | { | |
9c70220b | 48 | int ihl = skb->data - skb_transport_header(skb); |
7785bba2 | 49 | struct xfrm_offload *xo = xfrm_offload(skb); |
31a4ab93 | 50 | |
b0e380b1 | 51 | if (skb->transport_header != skb->network_header) { |
9c70220b ACM |
52 | memmove(skb_transport_header(skb), |
53 | skb_network_header(skb), ihl); | |
b0e380b1 | 54 | skb->network_header = skb->transport_header; |
7f5c0cb0 | 55 | } |
eddc9ec5 | 56 | ip_hdr(skb)->tot_len = htons(skb->len + ihl); |
7785bba2 SK |
57 | if (!xo || !(xo->flags & XFRM_GRO)) |
58 | skb_reset_transport_header(skb); | |
b59f45d0 HX |
59 | return 0; |
60 | } | |
61 | ||
c35fe410 SK |
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 | ||
b59f45d0 HX |
91 | static struct xfrm_mode xfrm4_transport_mode = { |
92 | .input = xfrm4_transport_input, | |
93 | .output = xfrm4_transport_output, | |
c35fe410 SK |
94 | .gso_segment = xfrm4_transport_gso_segment, |
95 | .xmit = xfrm4_transport_xmit, | |
b59f45d0 HX |
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); |