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
mpls_gso_segment(struct sk_buff * skb,netdev_features_t features)20 static 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
69 out:
70 return segs;
71 }
72
73 static 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
81 static 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
mpls_gso_init(void)89 static 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
mpls_gso_exit(void)99 static void __exit mpls_gso_exit(void)
100 {
101 dev_remove_offload(&mpls_uc_offload);
102 dev_remove_offload(&mpls_mc_offload);
103 }
104
105 module_init(mpls_gso_init);
106 module_exit(mpls_gso_exit);
107
108 MODULE_DESCRIPTION("MPLS GSO support");
109 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
110 MODULE_LICENSE("GPL");
111