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 | 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, len: 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, features: mpls_features); |
52 | if (IS_ERR_OR_NULL(ptr: segs)) { |
53 | skb_gso_error_unwind(skb, protocol: mpls_protocol, pulled_hlen: 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, len: mpls_hlen); |
67 | |
68 | skb_reset_mac_header(skb); |
69 | skb_set_network_header(skb, offset: 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(po: &mpls_uc_offload); |
97 | dev_add_offload(po: &mpls_mc_offload); |
98 | |
99 | return 0; |
100 | } |
101 | |
102 | static void __exit mpls_gso_exit(void) |
103 | { |
104 | dev_remove_offload(po: &mpls_uc_offload); |
105 | dev_remove_offload(po: &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 | |