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
mpls_gso_segment(struct sk_buff * skb,netdev_features_t features)19 static 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
68 out:
69 return segs;
70 }
71
72 static 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
80 static 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
mpls_gso_init(void)88 static 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
mpls_gso_exit(void)98 static void __exit mpls_gso_exit(void)
99 {
100 dev_remove_offload(&mpls_uc_offload);
101 dev_remove_offload(&mpls_mc_offload);
102 }
103
104 module_init(mpls_gso_init);
105 module_exit(mpls_gso_exit);
106
107 MODULE_DESCRIPTION("MPLS GSO support");
108 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
109 MODULE_LICENSE("GPL");
110