xref: /openbmc/linux/net/mpls/mpls_gso.c (revision b456cb98)
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 	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 
mpls_gso_init(void)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 
mpls_gso_exit(void)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