1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Network Service Header
4 *
5 * Copyright (c) 2017 Red Hat, Inc. -- Jiri Benc <jbenc@redhat.com>
6 */
7
8 #include <linux/module.h>
9 #include <linux/netdevice.h>
10 #include <linux/skbuff.h>
11 #include <net/nsh.h>
12 #include <net/tun_proto.h>
13
nsh_push(struct sk_buff * skb,const struct nshhdr * pushed_nh)14 int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh)
15 {
16 struct nshhdr *nh;
17 size_t length = nsh_hdr_len(pushed_nh);
18 u8 next_proto;
19
20 if (skb->mac_len) {
21 next_proto = TUN_P_ETHERNET;
22 } else {
23 next_proto = tun_p_from_eth_p(skb->protocol);
24 if (!next_proto)
25 return -EAFNOSUPPORT;
26 }
27
28 /* Add the NSH header */
29 if (skb_cow_head(skb, length) < 0)
30 return -ENOMEM;
31
32 skb_push(skb, length);
33 nh = (struct nshhdr *)(skb->data);
34 memcpy(nh, pushed_nh, length);
35 nh->np = next_proto;
36 skb_postpush_rcsum(skb, nh, length);
37
38 skb->protocol = htons(ETH_P_NSH);
39 skb_reset_mac_header(skb);
40 skb_reset_network_header(skb);
41 skb_reset_mac_len(skb);
42
43 return 0;
44 }
45 EXPORT_SYMBOL_GPL(nsh_push);
46
nsh_pop(struct sk_buff * skb)47 int nsh_pop(struct sk_buff *skb)
48 {
49 struct nshhdr *nh;
50 size_t length;
51 __be16 inner_proto;
52
53 if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
54 return -ENOMEM;
55 nh = (struct nshhdr *)(skb->data);
56 length = nsh_hdr_len(nh);
57 if (length < NSH_BASE_HDR_LEN)
58 return -EINVAL;
59 inner_proto = tun_p_to_eth_p(nh->np);
60 if (!pskb_may_pull(skb, length))
61 return -ENOMEM;
62
63 if (!inner_proto)
64 return -EAFNOSUPPORT;
65
66 skb_pull_rcsum(skb, length);
67 skb_reset_mac_header(skb);
68 skb_reset_network_header(skb);
69 skb_reset_mac_len(skb);
70 skb->protocol = inner_proto;
71
72 return 0;
73 }
74 EXPORT_SYMBOL_GPL(nsh_pop);
75
nsh_gso_segment(struct sk_buff * skb,netdev_features_t features)76 static struct sk_buff *nsh_gso_segment(struct sk_buff *skb,
77 netdev_features_t features)
78 {
79 struct sk_buff *segs = ERR_PTR(-EINVAL);
80 u16 mac_offset = skb->mac_header;
81 unsigned int nsh_len, mac_len;
82 __be16 proto;
83
84 skb_reset_network_header(skb);
85
86 mac_len = skb->mac_len;
87
88 if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN)))
89 goto out;
90 nsh_len = nsh_hdr_len(nsh_hdr(skb));
91 if (nsh_len < NSH_BASE_HDR_LEN)
92 goto out;
93 if (unlikely(!pskb_may_pull(skb, nsh_len)))
94 goto out;
95
96 proto = tun_p_to_eth_p(nsh_hdr(skb)->np);
97 if (!proto)
98 goto out;
99
100 __skb_pull(skb, nsh_len);
101
102 skb_reset_mac_header(skb);
103 skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0;
104 skb->protocol = proto;
105
106 features &= NETIF_F_SG;
107 segs = skb_mac_gso_segment(skb, features);
108 if (IS_ERR_OR_NULL(segs)) {
109 skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len,
110 mac_offset, mac_len);
111 goto out;
112 }
113
114 for (skb = segs; skb; skb = skb->next) {
115 skb->protocol = htons(ETH_P_NSH);
116 __skb_push(skb, nsh_len);
117 skb->mac_header = mac_offset;
118 skb->network_header = skb->mac_header + mac_len;
119 skb->mac_len = mac_len;
120 }
121
122 out:
123 return segs;
124 }
125
126 static struct packet_offload nsh_packet_offload __read_mostly = {
127 .type = htons(ETH_P_NSH),
128 .priority = 15,
129 .callbacks = {
130 .gso_segment = nsh_gso_segment,
131 },
132 };
133
nsh_init_module(void)134 static int __init nsh_init_module(void)
135 {
136 dev_add_offload(&nsh_packet_offload);
137 return 0;
138 }
139
nsh_cleanup_module(void)140 static void __exit nsh_cleanup_module(void)
141 {
142 dev_remove_offload(&nsh_packet_offload);
143 }
144
145 module_init(nsh_init_module);
146 module_exit(nsh_cleanup_module);
147
148 MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>");
149 MODULE_DESCRIPTION("NSH protocol");
150 MODULE_LICENSE("GPL v2");
151