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(error: -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, len: 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, features: mpls_features); |
49 | if (IS_ERR_OR_NULL(ptr: segs)) { |
50 | skb_gso_error_unwind(skb, protocol: mpls_protocol, pulled_hlen: 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, len: mpls_hlen); |
64 | |
65 | skb_reset_mac_header(skb); |
66 | skb_set_network_header(skb, offset: 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 | |
89 | static int __init mpls_gso_init(void) |
90 | { |
91 | pr_info("MPLS GSO support\n" ); |
92 | |
93 | dev_add_offload(po: &mpls_uc_offload); |
94 | dev_add_offload(po: &mpls_mc_offload); |
95 | |
96 | return 0; |
97 | } |
98 | |
99 | static void __exit mpls_gso_exit(void) |
100 | { |
101 | dev_remove_offload(po: &mpls_uc_offload); |
102 | dev_remove_offload(po: &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 | |