1 /*
2 * MPLS GSO Support
3 *
4 * Authors: Simon Horman (horms@verge.net.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 * Based on: GSO portions of net/ipv4/gre.c
12 */
13
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/netdev_features.h>
19 #include <linux/netdevice.h>
20 #include <linux/skbuff.h>
21
mpls_gso_segment(struct sk_buff * skb,netdev_features_t features)22 static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
23 netdev_features_t features)
24 {
25 struct sk_buff *segs = ERR_PTR(-EINVAL);
26 netdev_features_t mpls_features;
27 __be16 mpls_protocol;
28
29 if (unlikely(skb_shinfo(skb)->gso_type &
30 ~(SKB_GSO_TCPV4 |
31 SKB_GSO_TCPV6 |
32 SKB_GSO_UDP |
33 SKB_GSO_DODGY |
34 SKB_GSO_TCP_ECN)))
35 goto out;
36
37 /* Setup inner SKB. */
38 mpls_protocol = skb->protocol;
39 skb->protocol = skb->inner_protocol;
40
41 /* Push back the mac header that skb_mac_gso_segment() has pulled.
42 * It will be re-pulled by the call to skb_mac_gso_segment() below
43 */
44 __skb_push(skb, skb->mac_len);
45
46 /* Segment inner packet. */
47 mpls_features = skb->dev->mpls_features & features;
48 segs = skb_mac_gso_segment(skb, mpls_features);
49
50
51 /* Restore outer protocol. */
52 skb->protocol = mpls_protocol;
53
54 /* Re-pull the mac header that the call to skb_mac_gso_segment()
55 * above pulled. It will be re-pushed after returning
56 * skb_mac_gso_segment(), an indirect caller of this function.
57 */
58 __skb_pull(skb, skb->data - skb_mac_header(skb));
59 out:
60 return segs;
61 }
62
63 static struct packet_offload mpls_mc_offload __read_mostly = {
64 .type = cpu_to_be16(ETH_P_MPLS_MC),
65 .priority = 15,
66 .callbacks = {
67 .gso_segment = mpls_gso_segment,
68 },
69 };
70
71 static struct packet_offload mpls_uc_offload __read_mostly = {
72 .type = cpu_to_be16(ETH_P_MPLS_UC),
73 .priority = 15,
74 .callbacks = {
75 .gso_segment = mpls_gso_segment,
76 },
77 };
78
mpls_gso_init(void)79 static int __init mpls_gso_init(void)
80 {
81 pr_info("MPLS GSO support\n");
82
83 dev_add_offload(&mpls_uc_offload);
84 dev_add_offload(&mpls_mc_offload);
85
86 return 0;
87 }
88
mpls_gso_exit(void)89 static void __exit mpls_gso_exit(void)
90 {
91 dev_remove_offload(&mpls_uc_offload);
92 dev_remove_offload(&mpls_mc_offload);
93 }
94
95 module_init(mpls_gso_init);
96 module_exit(mpls_gso_exit);
97
98 MODULE_DESCRIPTION("MPLS GSO support");
99 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
100 MODULE_LICENSE("GPL");
101