1 /*
2 * Network Service Header
3 *
4 * Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/module.h>
12 #include <linux/netdevice.h>
13 #include <linux/skbuff.h>
14 #include <net/nsh.h>
15 #include <net/tun_proto.h>
16
nsh_gso_segment(struct sk_buff * skb,netdev_features_t features)17 static struct sk_buff *nsh_gso_segment(struct sk_buff *skb,
18 netdev_features_t features)
19 {
20 struct sk_buff *segs = ERR_PTR(-EINVAL);
21 unsigned int nsh_len, mac_len;
22 __be16 proto;
23 int nhoff;
24
25 skb_reset_network_header(skb);
26
27 nhoff = skb->network_header - skb->mac_header;
28 mac_len = skb->mac_len;
29
30 if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN)))
31 goto out;
32 nsh_len = nsh_hdr_len(nsh_hdr(skb));
33 if (nsh_len < NSH_BASE_HDR_LEN)
34 goto out;
35 if (unlikely(!pskb_may_pull(skb, nsh_len)))
36 goto out;
37
38 proto = tun_p_to_eth_p(nsh_hdr(skb)->np);
39 if (!proto)
40 goto out;
41
42 __skb_pull(skb, nsh_len);
43
44 skb_reset_mac_header(skb);
45 skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0;
46 skb->protocol = proto;
47
48 features &= NETIF_F_SG;
49 segs = skb_mac_gso_segment(skb, features);
50 if (IS_ERR_OR_NULL(segs)) {
51 skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len,
52 skb->network_header - nhoff,
53 mac_len);
54 goto out;
55 }
56
57 for (skb = segs; skb; skb = skb->next) {
58 skb->protocol = htons(ETH_P_NSH);
59 __skb_push(skb, nsh_len);
60 skb_set_mac_header(skb, -nhoff);
61 skb->network_header = skb->mac_header + mac_len;
62 skb->mac_len = mac_len;
63 }
64
65 out:
66 return segs;
67 }
68
69 static struct packet_offload nsh_packet_offload __read_mostly = {
70 .type = htons(ETH_P_NSH),
71 .priority = 15,
72 .callbacks = {
73 .gso_segment = nsh_gso_segment,
74 },
75 };
76
nsh_init_module(void)77 static int __init nsh_init_module(void)
78 {
79 dev_add_offload(&nsh_packet_offload);
80 return 0;
81 }
82
nsh_cleanup_module(void)83 static void __exit nsh_cleanup_module(void)
84 {
85 dev_remove_offload(&nsh_packet_offload);
86 }
87
88 module_init(nsh_init_module);
89 module_exit(nsh_cleanup_module);
90
91 MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>");
92 MODULE_DESCRIPTION("NSH protocol");
93 MODULE_LICENSE("GPL v2");
94