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/gso.h>
12 #include <net/nsh.h>
13 #include <net/tun_proto.h>
14
nsh_push(struct sk_buff * skb,const struct nshhdr * pushed_nh)15 int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh)
16 {
17 struct nshhdr *nh;
18 size_t length = nsh_hdr_len(pushed_nh);
19 u8 next_proto;
20
21 if (skb->mac_len) {
22 next_proto = TUN_P_ETHERNET;
23 } else {
24 next_proto = tun_p_from_eth_p(skb->protocol);
25 if (!next_proto)
26 return -EAFNOSUPPORT;
27 }
28
29 /* Add the NSH header */
30 if (skb_cow_head(skb, length) < 0)
31 return -ENOMEM;
32
33 skb_push(skb, length);
34 nh = (struct nshhdr *)(skb->data);
35 memcpy(nh, pushed_nh, length);
36 nh->np = next_proto;
37 skb_postpush_rcsum(skb, nh, length);
38
39 skb->protocol = htons(ETH_P_NSH);
40 skb_reset_mac_header(skb);
41 skb_reset_network_header(skb);
42 skb_reset_mac_len(skb);
43
44 return 0;
45 }
46 EXPORT_SYMBOL_GPL(nsh_push);
47
nsh_pop(struct sk_buff * skb)48 int nsh_pop(struct sk_buff *skb)
49 {
50 struct nshhdr *nh;
51 size_t length;
52 __be16 inner_proto;
53
54 if (!pskb_may_pull(skb, NSH_BASE_HDR_LEN))
55 return -ENOMEM;
56 nh = (struct nshhdr *)(skb->data);
57 length = nsh_hdr_len(nh);
58 if (length < NSH_BASE_HDR_LEN)
59 return -EINVAL;
60 inner_proto = tun_p_to_eth_p(nh->np);
61 if (!pskb_may_pull(skb, length))
62 return -ENOMEM;
63
64 if (!inner_proto)
65 return -EAFNOSUPPORT;
66
67 skb_pull_rcsum(skb, length);
68 skb_reset_mac_header(skb);
69 skb_reset_network_header(skb);
70 skb_reset_mac_len(skb);
71 skb->protocol = inner_proto;
72
73 return 0;
74 }
75 EXPORT_SYMBOL_GPL(nsh_pop);
76
nsh_gso_segment(struct sk_buff * skb,netdev_features_t features)77 static struct sk_buff *nsh_gso_segment(struct sk_buff *skb,
78 netdev_features_t features)
79 {
80 struct sk_buff *segs = ERR_PTR(-EINVAL);
81 u16 mac_offset = skb->mac_header;
82 unsigned int nsh_len, mac_len;
83 __be16 proto;
84
85 skb_reset_network_header(skb);
86
87 mac_len = skb->mac_len;
88
89 if (unlikely(!pskb_may_pull(skb, NSH_BASE_HDR_LEN)))
90 goto out;
91 nsh_len = nsh_hdr_len(nsh_hdr(skb));
92 if (nsh_len < NSH_BASE_HDR_LEN)
93 goto out;
94 if (unlikely(!pskb_may_pull(skb, nsh_len)))
95 goto out;
96
97 proto = tun_p_to_eth_p(nsh_hdr(skb)->np);
98 if (!proto)
99 goto out;
100
101 __skb_pull(skb, nsh_len);
102
103 skb_reset_mac_header(skb);
104 skb->mac_len = proto == htons(ETH_P_TEB) ? ETH_HLEN : 0;
105 skb->protocol = proto;
106
107 features &= NETIF_F_SG;
108 segs = skb_mac_gso_segment(skb, features);
109 if (IS_ERR_OR_NULL(segs)) {
110 skb_gso_error_unwind(skb, htons(ETH_P_NSH), nsh_len,
111 mac_offset, mac_len);
112 goto out;
113 }
114
115 for (skb = segs; skb; skb = skb->next) {
116 skb->protocol = htons(ETH_P_NSH);
117 __skb_push(skb, nsh_len);
118 skb->mac_header = mac_offset;
119 skb->network_header = skb->mac_header + mac_len;
120 skb->mac_len = mac_len;
121 }
122
123 out:
124 return segs;
125 }
126
127 static struct packet_offload nsh_packet_offload __read_mostly = {
128 .type = htons(ETH_P_NSH),
129 .priority = 15,
130 .callbacks = {
131 .gso_segment = nsh_gso_segment,
132 },
133 };
134
nsh_init_module(void)135 static int __init nsh_init_module(void)
136 {
137 dev_add_offload(&nsh_packet_offload);
138 return 0;
139 }
140
nsh_cleanup_module(void)141 static void __exit nsh_cleanup_module(void)
142 {
143 dev_remove_offload(&nsh_packet_offload);
144 }
145
146 module_init(nsh_init_module);
147 module_exit(nsh_cleanup_module);
148
149 MODULE_AUTHOR("Jiri Benc <jbenc@redhat.com>");
150 MODULE_DESCRIPTION("NSH protocol");
151 MODULE_LICENSE("GPL v2");
152
