blob: 55e6bfb3a28921c26b0be3170f10c1245a9a74ae [file] [log] [blame]
Daniel Borkmannc50cd352013-07-01 19:24:00 +02001/*
2 * IPV4 GSO/GRO offload support
3 * Linux INET implementation
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * GRE GSO support
11 */
12
13#include <linux/skbuff.h>
14#include <net/protocol.h>
15#include <net/gre.h>
16
17static int gre_gso_send_check(struct sk_buff *skb)
18{
19 if (!skb->encapsulation)
20 return -EINVAL;
21 return 0;
22}
23
24static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
25 netdev_features_t features)
26{
27 struct sk_buff *segs = ERR_PTR(-EINVAL);
28 netdev_features_t enc_features;
29 int ghl = GRE_HEADER_SECTION;
30 struct gre_base_hdr *greh;
31 int mac_len = skb->mac_len;
32 __be16 protocol = skb->protocol;
33 int tnl_hlen;
34 bool csum;
35
36 if (unlikely(skb_shinfo(skb)->gso_type &
37 ~(SKB_GSO_TCPV4 |
38 SKB_GSO_TCPV6 |
39 SKB_GSO_UDP |
40 SKB_GSO_DODGY |
41 SKB_GSO_TCP_ECN |
42 SKB_GSO_GRE)))
43 goto out;
44
45 if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
46 goto out;
47
48 greh = (struct gre_base_hdr *)skb_transport_header(skb);
49
50 if (greh->flags & GRE_KEY)
51 ghl += GRE_HEADER_SECTION;
52 if (greh->flags & GRE_SEQ)
53 ghl += GRE_HEADER_SECTION;
54 if (greh->flags & GRE_CSUM) {
55 ghl += GRE_HEADER_SECTION;
56 csum = true;
57 } else
58 csum = false;
59
60 /* setup inner skb. */
61 skb->protocol = greh->protocol;
62 skb->encapsulation = 0;
63
64 if (unlikely(!pskb_may_pull(skb, ghl)))
65 goto out;
66
67 __skb_pull(skb, ghl);
68 skb_reset_mac_header(skb);
69 skb_set_network_header(skb, skb_inner_network_offset(skb));
70 skb->mac_len = skb_inner_network_offset(skb);
71
72 /* segment inner packet. */
73 enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
74 segs = skb_mac_gso_segment(skb, enc_features);
75 if (!segs || IS_ERR(segs))
76 goto out;
77
78 skb = segs;
79 tnl_hlen = skb_tnl_header_len(skb);
80 do {
81 __skb_push(skb, ghl);
82 if (csum) {
83 __be32 *pcsum;
84
85 if (skb_has_shared_frag(skb)) {
86 int err;
87
88 err = __skb_linearize(skb);
89 if (err) {
David S. Miller0c1072a2013-07-03 14:50:41 -070090 kfree_skb_list(segs);
Daniel Borkmannc50cd352013-07-01 19:24:00 +020091 segs = ERR_PTR(err);
92 goto out;
93 }
94 }
95
96 greh = (struct gre_base_hdr *)(skb->data);
97 pcsum = (__be32 *)(greh + 1);
98 *pcsum = 0;
99 *(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0));
100 }
101 __skb_push(skb, tnl_hlen - ghl);
102
Alexander Duyckcdbaa0b2013-07-10 17:05:06 -0700103 skb_reset_inner_headers(skb);
104 skb->encapsulation = 1;
105
Daniel Borkmannc50cd352013-07-01 19:24:00 +0200106 skb_reset_mac_header(skb);
107 skb_set_network_header(skb, mac_len);
108 skb->mac_len = mac_len;
109 skb->protocol = protocol;
110 } while ((skb = skb->next));
111out:
112 return segs;
113}
114
115static const struct net_offload gre_offload = {
116 .callbacks = {
117 .gso_send_check = gre_gso_send_check,
118 .gso_segment = gre_gso_segment,
119 },
120};
121
122int __init gre_offload_init(void)
123{
124 return inet_add_offload(&gre_offload, IPPROTO_GRE);
125}
126
127void __exit gre_offload_exit(void)
128{
129 inet_del_offload(&gre_offload, IPPROTO_GRE);
130}