xref: /kernel/linux/linux-5.10/net/mpls/mpls_gso.c (revision 8c2ecf20) 
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/mpls.h>
18
19static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
20				       netdev_features_t features)
21{
22	struct sk_buff *segs = ERR_PTR(-EINVAL);
23	u16 mac_offset = skb->mac_header;
24	netdev_features_t mpls_features;
25	u16 mac_len = skb->mac_len;
26	__be16 mpls_protocol;
27	unsigned int mpls_hlen;
28
29	skb_reset_network_header(skb);
30	mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
31	if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
32		goto out;
33	if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
34		goto out;
35
36	/* Setup inner SKB. */
37	mpls_protocol = skb->protocol;
38	skb->protocol = skb->inner_protocol;
39
40	__skb_pull(skb, mpls_hlen);
41
42	skb->mac_len = 0;
43	skb_reset_mac_header(skb);
44
45	/* Segment inner packet. */
46	mpls_features = skb->dev->mpls_features & features;
47	segs = skb_mac_gso_segment(skb, mpls_features);
48	if (IS_ERR_OR_NULL(segs)) {
49		skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
50				     mac_len);
51		goto out;
52	}
53	skb = segs;
54
55	mpls_hlen += mac_len;
56	do {
57		skb->mac_len = mac_len;
58		skb->protocol = mpls_protocol;
59
60		skb_reset_inner_network_header(skb);
61
62		__skb_push(skb, mpls_hlen);
63
64		skb_reset_mac_header(skb);
65		skb_set_network_header(skb, mac_len);
66	} while ((skb = skb->next));
67
68out:
69	return segs;
70}
71
72static struct packet_offload mpls_mc_offload __read_mostly = {
73	.type = cpu_to_be16(ETH_P_MPLS_MC),
74	.priority = 15,
75	.callbacks = {
76		.gso_segment    =	mpls_gso_segment,
77	},
78};
79
80static struct packet_offload mpls_uc_offload __read_mostly = {
81	.type = cpu_to_be16(ETH_P_MPLS_UC),
82	.priority = 15,
83	.callbacks = {
84		.gso_segment    =	mpls_gso_segment,
85	},
86};
87
88static int __init mpls_gso_init(void)
89{
90	pr_info("MPLS GSO support\n");
91
92	dev_add_offload(&mpls_uc_offload);
93	dev_add_offload(&mpls_mc_offload);
94
95	return 0;
96}
97
98static void __exit mpls_gso_exit(void)
99{
100	dev_remove_offload(&mpls_uc_offload);
101	dev_remove_offload(&mpls_mc_offload);
102}
103
104module_init(mpls_gso_init);
105module_exit(mpls_gso_exit);
106
107MODULE_DESCRIPTION("MPLS GSO support");
108MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
109MODULE_LICENSE("GPL");
110