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
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 if (!skb_inner_network_header_was_set(skb))
31 goto out;
32
33 skb_reset_network_header(skb);
34 mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
35 if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
36 goto out;
37 if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
38 goto out;
39
40 /* Setup inner SKB. */
41 mpls_protocol = skb->protocol;
42 skb->protocol = skb->inner_protocol;
43
44 __skb_pull(skb, mpls_hlen);
45
46 skb->mac_len = 0;
47 skb_reset_mac_header(skb);
48
49 /* Segment inner packet. */
50 mpls_features = skb->dev->mpls_features & features;
51 segs = skb_mac_gso_segment(skb, mpls_features);
52 if (IS_ERR_OR_NULL(segs)) {
53 skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
54 mac_len);
55 goto out;
56 }
57 skb = segs;
58
59 mpls_hlen += mac_len;
60 do {
61 skb->mac_len = mac_len;
62 skb->protocol = mpls_protocol;
63
64 skb_reset_inner_network_header(skb);
65
66 __skb_push(skb, mpls_hlen);
67
68 skb_reset_mac_header(skb);
69 skb_set_network_header(skb, mac_len);
70 } while ((skb = skb->next));
71
72 out:
73 return segs;
74 }
75
76 static struct packet_offload mpls_mc_offload __read_mostly = {
77 .type = cpu_to_be16(ETH_P_MPLS_MC),
78 .priority = 15,
79 .callbacks = {
80 .gso_segment = mpls_gso_segment,
81 },
82 };
83
84 static struct packet_offload mpls_uc_offload __read_mostly = {
85 .type = cpu_to_be16(ETH_P_MPLS_UC),
86 .priority = 15,
87 .callbacks = {
88 .gso_segment = mpls_gso_segment,
89 },
90 };
91
92 static int __init mpls_gso_init(void)
93 {
94 pr_info("MPLS GSO support\n");
95
96 dev_add_offload(&mpls_uc_offload);
97 dev_add_offload(&mpls_mc_offload);
98
99 return 0;
100 }
101
102 static void __exit mpls_gso_exit(void)
103 {
104 dev_remove_offload(&mpls_uc_offload);
105 dev_remove_offload(&mpls_mc_offload);
106 }
107
108 module_init(mpls_gso_init);
109 module_exit(mpls_gso_exit);
110
111 MODULE_DESCRIPTION("MPLS GSO support");
112 MODULE_AUTHOR("Simon Horman <horms@verge.net.au>");
113 MODULE_LICENSE("GPL");
114
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