1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * MPLS GSO Support
4 *
5 * Authors: Simon Horman (horms@verge.net.au)
6 *
7 * Based on: GSO portions of net/ipv4/gre.c
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/err.h>
13#include <linux/module.h>
14#include <linux/netdev_features.h>
15#include <linux/netdevice.h>
16#include <linux/skbuff.h>
17#include <net/gso.h>
18#include <net/mpls.h>
19
20static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
21 netdev_features_t features)
22{
23 struct sk_buff *segs = ERR_PTR(error: -EINVAL);
24 u16 mac_offset = skb->mac_header;
25 netdev_features_t mpls_features;
26 u16 mac_len = skb->mac_len;
27 __be16 mpls_protocol;
28 unsigned int mpls_hlen;
29
30 if (!skb_inner_network_header_was_set(skb))
31 goto out;
32
33 skb_reset_network_header(skb);
34 mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
35 if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
36 goto out;
37 if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
38 goto out;
39
40 /* Setup inner SKB. */
41 mpls_protocol = skb->protocol;
42 skb->protocol = skb->inner_protocol;
43
44 __skb_pull(skb, len: mpls_hlen);
45
46 skb->mac_len = 0;
47 skb_reset_mac_header(skb);
48
49 /* Segment inner packet. */
50 mpls_features = skb->dev->mpls_features & features;
51 segs = skb_mac_gso_segment(skb, features: mpls_features);
52 if (IS_ERR_OR_NULL(ptr: segs)) {
53 skb_gso_error_unwind(skb, protocol: mpls_protocol, pulled_hlen: mpls_hlen, mac_offset,
54 mac_len);
55 goto out;
56 }
57 skb = segs;
58
59 mpls_hlen += mac_len;
60 do {
61 skb->mac_len = mac_len;
62 skb->protocol = mpls_protocol;
63
64 skb_reset_inner_network_header(skb);
65
66 __skb_push(skb, len: mpls_hlen);
67
68 skb_reset_mac_header(skb);
69 skb_set_network_header(skb, offset: mac_len);
70 } while ((skb = skb->next));
71
72out:
73 return segs;
74}
75
76static struct packet_offload mpls_mc_offload __read_mostly = {
77 .type = cpu_to_be16(ETH_P_MPLS_MC),
78 .priority = 15,
79 .callbacks = {
80 .gso_segment = mpls_gso_segment,
81 },
82};
83
84static struct packet_offload mpls_uc_offload __read_mostly = {
85 .type = cpu_to_be16(ETH_P_MPLS_UC),
86 .priority = 15,
87 .callbacks = {
88 .gso_segment = mpls_gso_segment,
89 },
90};
91
92static int __init mpls_gso_init(void)
93{
94 pr_info("MPLS GSO support\n");
95
96 dev_add_offload(po: &mpls_uc_offload);
97 dev_add_offload(po: &mpls_mc_offload);
98
99 return 0;
100}
101
102static void __exit mpls_gso_exit(void)
103{
104 dev_remove_offload(po: &mpls_uc_offload);
105 dev_remove_offload(po: &mpls_mc_offload);
106}
107
108module_init(mpls_gso_init);
109module_exit(mpls_gso_exit);
110
111MODULE_DESCRIPTION("MPLS GSO support");
112MODULE_AUTHOR("Simon Horman <horms@verge.net.au>");
113MODULE_LICENSE("GPL");
114

source code of linux/net/mpls/mpls_gso.c