blob: 2cd02f32f99f568c8275389aefd754700a77efa6 [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;
Wei-Chun Chao7a7ffba2013-12-26 13:10:22 -080031 u16 mac_offset = skb->mac_header;
Daniel Borkmannc50cd352013-07-01 19:24:00 +020032 int mac_len = skb->mac_len;
33 __be16 protocol = skb->protocol;
34 int tnl_hlen;
35 bool csum;
36
37 if (unlikely(skb_shinfo(skb)->gso_type &
38 ~(SKB_GSO_TCPV4 |
39 SKB_GSO_TCPV6 |
40 SKB_GSO_UDP |
41 SKB_GSO_DODGY |
42 SKB_GSO_TCP_ECN |
Eric Dumazetcb32f512013-10-19 11:42:57 -070043 SKB_GSO_GRE |
44 SKB_GSO_IPIP)))
Daniel Borkmannc50cd352013-07-01 19:24:00 +020045 goto out;
46
47 if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
48 goto out;
49
50 greh = (struct gre_base_hdr *)skb_transport_header(skb);
51
52 if (greh->flags & GRE_KEY)
53 ghl += GRE_HEADER_SECTION;
54 if (greh->flags & GRE_SEQ)
55 ghl += GRE_HEADER_SECTION;
56 if (greh->flags & GRE_CSUM) {
57 ghl += GRE_HEADER_SECTION;
58 csum = true;
59 } else
60 csum = false;
61
Wei-Chun Chao7a7ffba2013-12-26 13:10:22 -080062 if (unlikely(!pskb_may_pull(skb, ghl)))
63 goto out;
64
Daniel Borkmannc50cd352013-07-01 19:24:00 +020065 /* setup inner skb. */
66 skb->protocol = greh->protocol;
67 skb->encapsulation = 0;
68
Daniel Borkmannc50cd352013-07-01 19:24:00 +020069 __skb_pull(skb, ghl);
70 skb_reset_mac_header(skb);
71 skb_set_network_header(skb, skb_inner_network_offset(skb));
72 skb->mac_len = skb_inner_network_offset(skb);
73
74 /* segment inner packet. */
75 enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
76 segs = skb_mac_gso_segment(skb, enc_features);
Wei-Chun Chao7a7ffba2013-12-26 13:10:22 -080077 if (!segs || IS_ERR(segs)) {
78 skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
Daniel Borkmannc50cd352013-07-01 19:24:00 +020079 goto out;
Wei-Chun Chao7a7ffba2013-12-26 13:10:22 -080080 }
Daniel Borkmannc50cd352013-07-01 19:24:00 +020081
82 skb = segs;
83 tnl_hlen = skb_tnl_header_len(skb);
84 do {
85 __skb_push(skb, ghl);
86 if (csum) {
87 __be32 *pcsum;
88
89 if (skb_has_shared_frag(skb)) {
90 int err;
91
92 err = __skb_linearize(skb);
93 if (err) {
David S. Miller0c1072a2013-07-03 14:50:41 -070094 kfree_skb_list(segs);
Daniel Borkmannc50cd352013-07-01 19:24:00 +020095 segs = ERR_PTR(err);
96 goto out;
97 }
98 }
99
100 greh = (struct gre_base_hdr *)(skb->data);
101 pcsum = (__be32 *)(greh + 1);
102 *pcsum = 0;
103 *(__sum16 *)pcsum = csum_fold(skb_checksum(skb, 0, skb->len, 0));
104 }
105 __skb_push(skb, tnl_hlen - ghl);
106
Alexander Duyckcdbaa0b2013-07-10 17:05:06 -0700107 skb_reset_inner_headers(skb);
108 skb->encapsulation = 1;
109
Daniel Borkmannc50cd352013-07-01 19:24:00 +0200110 skb_reset_mac_header(skb);
111 skb_set_network_header(skb, mac_len);
112 skb->mac_len = mac_len;
113 skb->protocol = protocol;
114 } while ((skb = skb->next));
115out:
116 return segs;
117}
118
119static const struct net_offload gre_offload = {
120 .callbacks = {
121 .gso_send_check = gre_gso_send_check,
122 .gso_segment = gre_gso_segment,
123 },
124};
125
126int __init gre_offload_init(void)
127{
128 return inet_add_offload(&gre_offload, IPPROTO_GRE);
129}
130
131void __exit gre_offload_exit(void)
132{
133 inet_del_offload(&gre_offload, IPPROTO_GRE);
134}