xref: /kernel/linux/linux-6.6/net/mpls/mpls_gso.c (revision 62306a36) 
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(-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	skb_reset_network_header(skb);
31	mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
32	if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
33		goto out;
34	if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
35		goto out;
36
37	/* Setup inner SKB. */
38	mpls_protocol = skb->protocol;
39	skb->protocol = skb->inner_protocol;
40
41	__skb_pull(skb, mpls_hlen);
42
43	skb->mac_len = 0;
44	skb_reset_mac_header(skb);
45
46	/* Segment inner packet. */
47	mpls_features = skb->dev->mpls_features & features;
48	segs = skb_mac_gso_segment(skb, mpls_features);
49	if (IS_ERR_OR_NULL(segs)) {
50		skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
51				     mac_len);
52		goto out;
53	}
54	skb = segs;
55
56	mpls_hlen += mac_len;
57	do {
58		skb->mac_len = mac_len;
59		skb->protocol = mpls_protocol;
60
61		skb_reset_inner_network_header(skb);
62
63		__skb_push(skb, mpls_hlen);
64
65		skb_reset_mac_header(skb);
66		skb_set_network_header(skb, mac_len);
67	} while ((skb = skb->next));
68
69out:
70	return segs;
71}
72
73static struct packet_offload mpls_mc_offload __read_mostly = {
74	.type = cpu_to_be16(ETH_P_MPLS_MC),
75	.priority = 15,
76	.callbacks = {
77		.gso_segment    =	mpls_gso_segment,
78	},
79};
80
81static struct packet_offload mpls_uc_offload __read_mostly = {
82	.type = cpu_to_be16(ETH_P_MPLS_UC),
83	.priority = 15,
84	.callbacks = {
85		.gso_segment    =	mpls_gso_segment,
86	},
87};
88
89static int __init mpls_gso_init(void)
90{
91	pr_info("MPLS GSO support\n");
92
93	dev_add_offload(&mpls_uc_offload);
94	dev_add_offload(&mpls_mc_offload);
95
96	return 0;
97}
98
99static void __exit mpls_gso_exit(void)
100{
101	dev_remove_offload(&mpls_uc_offload);
102	dev_remove_offload(&mpls_mc_offload);
103}
104
105module_init(mpls_gso_init);
106module_exit(mpls_gso_exit);
107
108MODULE_DESCRIPTION("MPLS GSO support");
109MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
110MODULE_LICENSE("GPL");
111