1/* SPDX-License-Identifier: GPL-2.0-or-later */
2#ifndef TUN_VNET_H
3#define TUN_VNET_H
4
5/* High bits in flags field are unused. */
6#define TUN_VNET_LE 0x80000000
7#define TUN_VNET_BE 0x40000000
8
9#define TUN_VNET_TNL_SIZE sizeof(struct virtio_net_hdr_v1_hash_tunnel)
10
11static inline bool tun_vnet_legacy_is_little_endian(unsigned int flags)
12{
13 bool be = IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
14 (flags & TUN_VNET_BE);
15
16 return !be && virtio_legacy_is_little_endian();
17}
18
19static inline long tun_get_vnet_be(unsigned int flags, int __user *argp)
20{
21 int be = !!(flags & TUN_VNET_BE);
22
23 if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
24 return -EINVAL;
25
26 if (put_user(be, argp))
27 return -EFAULT;
28
29 return 0;
30}
31
32static inline long tun_set_vnet_be(unsigned int *flags, int __user *argp)
33{
34 int be;
35
36 if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
37 return -EINVAL;
38
39 if (get_user(be, argp))
40 return -EFAULT;
41
42 if (be)
43 *flags |= TUN_VNET_BE;
44 else
45 *flags &= ~TUN_VNET_BE;
46
47 return 0;
48}
49
50static inline bool tun_vnet_is_little_endian(unsigned int flags)
51{
52 return flags & TUN_VNET_LE || tun_vnet_legacy_is_little_endian(flags);
53}
54
55static inline u16 tun_vnet16_to_cpu(unsigned int flags, __virtio16 val)
56{
57 return __virtio16_to_cpu(little_endian: tun_vnet_is_little_endian(flags), val);
58}
59
60static inline __virtio16 cpu_to_tun_vnet16(unsigned int flags, u16 val)
61{
62 return __cpu_to_virtio16(little_endian: tun_vnet_is_little_endian(flags), val);
63}
64
65static inline long tun_vnet_ioctl(int *vnet_hdr_sz, unsigned int *flags,
66 unsigned int cmd, int __user *sp)
67{
68 int s;
69
70 switch (cmd) {
71 case TUNGETVNETHDRSZ:
72 s = *vnet_hdr_sz;
73 if (put_user(s, sp))
74 return -EFAULT;
75 return 0;
76
77 case TUNSETVNETHDRSZ:
78 if (get_user(s, sp))
79 return -EFAULT;
80 if (s < (int)sizeof(struct virtio_net_hdr))
81 return -EINVAL;
82
83 *vnet_hdr_sz = s;
84 return 0;
85
86 case TUNGETVNETLE:
87 s = !!(*flags & TUN_VNET_LE);
88 if (put_user(s, sp))
89 return -EFAULT;
90 return 0;
91
92 case TUNSETVNETLE:
93 if (get_user(s, sp))
94 return -EFAULT;
95 if (s)
96 *flags |= TUN_VNET_LE;
97 else
98 *flags &= ~TUN_VNET_LE;
99 return 0;
100
101 case TUNGETVNETBE:
102 return tun_get_vnet_be(flags: *flags, argp: sp);
103
104 case TUNSETVNETBE:
105 return tun_set_vnet_be(flags, argp: sp);
106
107 default:
108 return -EINVAL;
109 }
110}
111
112static inline unsigned int tun_vnet_parse_size(netdev_features_t features)
113{
114 if (!(features & NETIF_F_GSO_UDP_TUNNEL))
115 return sizeof(struct virtio_net_hdr);
116
117 return TUN_VNET_TNL_SIZE;
118}
119
120static inline int __tun_vnet_hdr_get(int sz, unsigned int flags,
121 netdev_features_t features,
122 struct iov_iter *from,
123 struct virtio_net_hdr *hdr)
124{
125 unsigned int parsed_size = tun_vnet_parse_size(features);
126 u16 hdr_len;
127
128 if (iov_iter_count(i: from) < sz)
129 return -EINVAL;
130
131 if (!copy_from_iter_full(addr: hdr, bytes: parsed_size, i: from))
132 return -EFAULT;
133
134 hdr_len = tun_vnet16_to_cpu(flags, val: hdr->hdr_len);
135
136 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
137 hdr_len = max(tun_vnet16_to_cpu(flags, hdr->csum_start) + tun_vnet16_to_cpu(flags, hdr->csum_offset) + 2, hdr_len);
138 hdr->hdr_len = cpu_to_tun_vnet16(flags, val: hdr_len);
139 }
140
141 if (hdr_len > iov_iter_count(i: from))
142 return -EINVAL;
143
144 iov_iter_advance(i: from, bytes: sz - parsed_size);
145
146 return hdr_len;
147}
148
149static inline int tun_vnet_hdr_get(int sz, unsigned int flags,
150 struct iov_iter *from,
151 struct virtio_net_hdr *hdr)
152{
153 return __tun_vnet_hdr_get(sz, flags, features: 0, from, hdr);
154}
155
156static inline int __tun_vnet_hdr_put(int sz, netdev_features_t features,
157 struct iov_iter *iter,
158 const struct virtio_net_hdr *hdr)
159{
160 unsigned int parsed_size = tun_vnet_parse_size(features);
161
162 if (unlikely(iov_iter_count(iter) < sz))
163 return -EINVAL;
164
165 if (unlikely(copy_to_iter(hdr, parsed_size, iter) != parsed_size))
166 return -EFAULT;
167
168 if (iov_iter_zero(bytes: sz - parsed_size, iter) != sz - parsed_size)
169 return -EFAULT;
170
171 return 0;
172}
173
174static inline int tun_vnet_hdr_put(int sz, struct iov_iter *iter,
175 const struct virtio_net_hdr *hdr)
176{
177 return __tun_vnet_hdr_put(sz, features: 0, iter, hdr);
178}
179
180static inline int tun_vnet_hdr_to_skb(unsigned int flags, struct sk_buff *skb,
181 const struct virtio_net_hdr *hdr)
182{
183 return virtio_net_hdr_to_skb(skb, hdr, little_endian: tun_vnet_is_little_endian(flags));
184}
185
186/*
187 * Tun is not aware of the negotiated guest features, guess them from the
188 * virtio net hdr size
189 */
190static inline netdev_features_t tun_vnet_hdr_guest_features(int vnet_hdr_sz)
191{
192 if (vnet_hdr_sz >= TUN_VNET_TNL_SIZE)
193 return NETIF_F_GSO_UDP_TUNNEL | NETIF_F_GSO_UDP_TUNNEL_CSUM;
194 return 0;
195}
196
197static inline int
198tun_vnet_hdr_tnl_to_skb(unsigned int flags, netdev_features_t features,
199 struct sk_buff *skb,
200 const struct virtio_net_hdr_v1_hash_tunnel *hdr)
201{
202 return virtio_net_hdr_tnl_to_skb(skb, vhdr: hdr,
203 tnl_hdr_negotiated: features & NETIF_F_GSO_UDP_TUNNEL,
204 tnl_csum_negotiated: features & NETIF_F_GSO_UDP_TUNNEL_CSUM,
205 little_endian: tun_vnet_is_little_endian(flags));
206}
207
208static inline int tun_vnet_hdr_from_skb(unsigned int flags,
209 const struct net_device *dev,
210 const struct sk_buff *skb,
211 struct virtio_net_hdr *hdr)
212{
213 int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
214
215 if (virtio_net_hdr_from_skb(skb, hdr,
216 little_endian: tun_vnet_is_little_endian(flags), has_data_valid: true,
217 vlan_hlen)) {
218 struct skb_shared_info *sinfo = skb_shinfo(skb);
219
220 if (net_ratelimit()) {
221 netdev_err(dev, format: "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
222 sinfo->gso_type, tun_vnet16_to_cpu(flags, val: hdr->gso_size),
223 tun_vnet16_to_cpu(flags, val: hdr->hdr_len));
224 print_hex_dump(KERN_ERR, prefix_str: "tun: ",
225 prefix_type: DUMP_PREFIX_NONE,
226 rowsize: 16, groupsize: 1, buf: skb->head,
227 min(tun_vnet16_to_cpu(flags, hdr->hdr_len), 64), ascii: true);
228 }
229 WARN_ON_ONCE(1);
230 return -EINVAL;
231 }
232
233 return 0;
234}
235
236static inline int
237tun_vnet_hdr_tnl_from_skb(unsigned int flags,
238 const struct net_device *dev,
239 const struct sk_buff *skb,
240 struct virtio_net_hdr_v1_hash_tunnel *tnl_hdr)
241{
242 bool has_tnl_offload = !!(dev->features & NETIF_F_GSO_UDP_TUNNEL);
243 int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0;
244
245 if (virtio_net_hdr_tnl_from_skb(skb, vhdr: tnl_hdr, tnl_hdr_negotiated: has_tnl_offload,
246 little_endian: tun_vnet_is_little_endian(flags),
247 vlan_hlen, has_data_valid: true)) {
248 struct virtio_net_hdr_v1 *hdr = &tnl_hdr->hash_hdr.hdr;
249 struct skb_shared_info *sinfo = skb_shinfo(skb);
250
251 if (net_ratelimit()) {
252 int hdr_len = tun_vnet16_to_cpu(flags, val: hdr->hdr_len);
253
254 netdev_err(dev, format: "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
255 sinfo->gso_type,
256 tun_vnet16_to_cpu(flags, val: hdr->gso_size),
257 tun_vnet16_to_cpu(flags, val: hdr->hdr_len));
258 print_hex_dump(KERN_ERR, prefix_str: "tun: ", prefix_type: DUMP_PREFIX_NONE,
259 rowsize: 16, groupsize: 1, buf: skb->head, min(hdr_len, 64),
260 ascii: true);
261 }
262 WARN_ON_ONCE(1);
263 return -EINVAL;
264 }
265
266 return 0;
267}
268
269#endif /* TUN_VNET_H */
270

source code of linux/drivers/net/tun_vnet.h