1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * MPLS GSO Support
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Authors: Simon Horman (horms@verge.net.au)
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Based on: GSO portions of net/ipv4/gre.c
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/err.h>
13*4882a593Smuzhiyun #include <linux/module.h>
14*4882a593Smuzhiyun #include <linux/netdev_features.h>
15*4882a593Smuzhiyun #include <linux/netdevice.h>
16*4882a593Smuzhiyun #include <linux/skbuff.h>
17*4882a593Smuzhiyun #include <net/mpls.h>
18*4882a593Smuzhiyun
mpls_gso_segment(struct sk_buff * skb,netdev_features_t features)19*4882a593Smuzhiyun static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
20*4882a593Smuzhiyun netdev_features_t features)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun struct sk_buff *segs = ERR_PTR(-EINVAL);
23*4882a593Smuzhiyun u16 mac_offset = skb->mac_header;
24*4882a593Smuzhiyun netdev_features_t mpls_features;
25*4882a593Smuzhiyun u16 mac_len = skb->mac_len;
26*4882a593Smuzhiyun __be16 mpls_protocol;
27*4882a593Smuzhiyun unsigned int mpls_hlen;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun skb_reset_network_header(skb);
30*4882a593Smuzhiyun mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
31*4882a593Smuzhiyun if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
32*4882a593Smuzhiyun goto out;
33*4882a593Smuzhiyun if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
34*4882a593Smuzhiyun goto out;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun /* Setup inner SKB. */
37*4882a593Smuzhiyun mpls_protocol = skb->protocol;
38*4882a593Smuzhiyun skb->protocol = skb->inner_protocol;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun __skb_pull(skb, mpls_hlen);
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun skb->mac_len = 0;
43*4882a593Smuzhiyun skb_reset_mac_header(skb);
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun /* Segment inner packet. */
46*4882a593Smuzhiyun mpls_features = skb->dev->mpls_features & features;
47*4882a593Smuzhiyun segs = skb_mac_gso_segment(skb, mpls_features);
48*4882a593Smuzhiyun if (IS_ERR_OR_NULL(segs)) {
49*4882a593Smuzhiyun skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
50*4882a593Smuzhiyun mac_len);
51*4882a593Smuzhiyun goto out;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun skb = segs;
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun mpls_hlen += mac_len;
56*4882a593Smuzhiyun do {
57*4882a593Smuzhiyun skb->mac_len = mac_len;
58*4882a593Smuzhiyun skb->protocol = mpls_protocol;
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun skb_reset_inner_network_header(skb);
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun __skb_push(skb, mpls_hlen);
63*4882a593Smuzhiyun
64*4882a593Smuzhiyun skb_reset_mac_header(skb);
65*4882a593Smuzhiyun skb_set_network_header(skb, mac_len);
66*4882a593Smuzhiyun } while ((skb = skb->next));
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun out:
69*4882a593Smuzhiyun return segs;
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun static struct packet_offload mpls_mc_offload __read_mostly = {
73*4882a593Smuzhiyun .type = cpu_to_be16(ETH_P_MPLS_MC),
74*4882a593Smuzhiyun .priority = 15,
75*4882a593Smuzhiyun .callbacks = {
76*4882a593Smuzhiyun .gso_segment = mpls_gso_segment,
77*4882a593Smuzhiyun },
78*4882a593Smuzhiyun };
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun static struct packet_offload mpls_uc_offload __read_mostly = {
81*4882a593Smuzhiyun .type = cpu_to_be16(ETH_P_MPLS_UC),
82*4882a593Smuzhiyun .priority = 15,
83*4882a593Smuzhiyun .callbacks = {
84*4882a593Smuzhiyun .gso_segment = mpls_gso_segment,
85*4882a593Smuzhiyun },
86*4882a593Smuzhiyun };
87*4882a593Smuzhiyun
mpls_gso_init(void)88*4882a593Smuzhiyun static int __init mpls_gso_init(void)
89*4882a593Smuzhiyun {
90*4882a593Smuzhiyun pr_info("MPLS GSO support\n");
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun dev_add_offload(&mpls_uc_offload);
93*4882a593Smuzhiyun dev_add_offload(&mpls_mc_offload);
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun return 0;
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun
mpls_gso_exit(void)98*4882a593Smuzhiyun static void __exit mpls_gso_exit(void)
99*4882a593Smuzhiyun {
100*4882a593Smuzhiyun dev_remove_offload(&mpls_uc_offload);
101*4882a593Smuzhiyun dev_remove_offload(&mpls_mc_offload);
102*4882a593Smuzhiyun }
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun module_init(mpls_gso_init);
105*4882a593Smuzhiyun module_exit(mpls_gso_exit);
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun MODULE_DESCRIPTION("MPLS GSO support");
108*4882a593Smuzhiyun MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
109*4882a593Smuzhiyun MODULE_LICENSE("GPL");
110