1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_NET_H
3 #define _LINUX_VIRTIO_NET_H
4
5 #include <linux/if_vlan.h>
6 #include <linux/ip.h>
7 #include <linux/ipv6.h>
8 #include <linux/udp.h>
9 #include <uapi/linux/tcp.h>
10 #include <uapi/linux/virtio_net.h>
11
12 static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type)
13 {
14 switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
15 case VIRTIO_NET_HDR_GSO_TCPV4:
16 return protocol == cpu_to_be16(ETH_P_IP);
17 case VIRTIO_NET_HDR_GSO_TCPV6:
18 return protocol == cpu_to_be16(ETH_P_IPV6);
19 case VIRTIO_NET_HDR_GSO_UDP:
20 case VIRTIO_NET_HDR_GSO_UDP_L4:
21 return protocol == cpu_to_be16(ETH_P_IP) ||
22 protocol == cpu_to_be16(ETH_P_IPV6);
23 default:
24 return false;
25 }
26 }
27
28 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
29 const struct virtio_net_hdr *hdr)
30 {
31 if (skb->protocol)
32 return 0;
33
34 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
35 case VIRTIO_NET_HDR_GSO_TCPV4:
36 case VIRTIO_NET_HDR_GSO_UDP:
37 case VIRTIO_NET_HDR_GSO_UDP_L4:
38 skb->protocol = cpu_to_be16(ETH_P_IP);
39 break;
40 case VIRTIO_NET_HDR_GSO_TCPV6:
41 skb->protocol = cpu_to_be16(ETH_P_IPV6);
42 break;
43 default:
44 return -EINVAL;
45 }
46
47 return 0;
48 }
49
50 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
51 const struct virtio_net_hdr *hdr,
52 bool little_endian)
53 {
54 unsigned int nh_min_len = sizeof(struct iphdr);
55 unsigned int gso_type = 0;
56 unsigned int thlen = 0;
57 unsigned int p_off = 0;
58 unsigned int ip_proto;
59
60 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
61 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
62 case VIRTIO_NET_HDR_GSO_TCPV4:
63 gso_type = SKB_GSO_TCPV4;
64 ip_proto = IPPROTO_TCP;
65 thlen = sizeof(struct tcphdr);
66 break;
67 case VIRTIO_NET_HDR_GSO_TCPV6:
68 gso_type = SKB_GSO_TCPV6;
69 ip_proto = IPPROTO_TCP;
70 thlen = sizeof(struct tcphdr);
71 nh_min_len = sizeof(struct ipv6hdr);
72 break;
73 case VIRTIO_NET_HDR_GSO_UDP:
74 gso_type = SKB_GSO_UDP;
75 ip_proto = IPPROTO_UDP;
76 thlen = sizeof(struct udphdr);
77 break;
78 case VIRTIO_NET_HDR_GSO_UDP_L4:
79 gso_type = SKB_GSO_UDP_L4;
80 ip_proto = IPPROTO_UDP;
81 thlen = sizeof(struct udphdr);
82 break;
83 default:
84 return -EINVAL;
85 }
86
87 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
88 gso_type |= SKB_GSO_TCP_ECN;
89
90 if (hdr->gso_size == 0)
91 return -EINVAL;
92 }
93
94 skb_reset_mac_header(skb);
95
96 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
97 u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
98 u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
99 u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16));
100
101 if (!pskb_may_pull(skb, needed))
102 return -EINVAL;
103
104 if (!skb_partial_csum_set(skb, start, off))
105 return -EINVAL;
106 if (skb_transport_offset(skb) < nh_min_len)
107 return -EINVAL;
108
109 nh_min_len = skb_transport_offset(skb);
110 p_off = nh_min_len + thlen;
111 if (!pskb_may_pull(skb, p_off))
112 return -EINVAL;
113 } else {
114 /* gso packets without NEEDS_CSUM do not set transport_offset.
115 * probe and drop if does not match one of the above types.
116 */
117 if (gso_type && skb->network_header) {
118 struct flow_keys_basic keys;
119
120 if (!skb->protocol) {
121 __be16 protocol = dev_parse_header_protocol(skb);
122
123 if (!protocol)
124 virtio_net_hdr_set_proto(skb, hdr);
125 else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))
126 return -EINVAL;
127 else
128 skb->protocol = protocol;
129 }
130 retry:
131 if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
132 NULL, 0, 0, 0,
133 0)) {
134 /* UFO does not specify ipv4 or 6: try both */
135 if (gso_type & SKB_GSO_UDP &&
136 skb->protocol == htons(ETH_P_IP)) {
137 skb->protocol = htons(ETH_P_IPV6);
138 goto retry;
139 }
140 return -EINVAL;
141 }
142
143 p_off = keys.control.thoff + thlen;
144 if (!pskb_may_pull(skb, p_off) ||
145 keys.basic.ip_proto != ip_proto)
146 return -EINVAL;
147
148 skb_set_transport_header(skb, keys.control.thoff);
149 } else if (gso_type) {
150 p_off = nh_min_len + thlen;
151 if (!pskb_may_pull(skb, p_off))
152 return -EINVAL;
153 }
154 }
155
156 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
157 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
158 unsigned int nh_off = p_off;
159 struct skb_shared_info *shinfo = skb_shinfo(skb);
160
161 switch (gso_type & ~SKB_GSO_TCP_ECN) {
162 case SKB_GSO_UDP:
163 /* UFO may not include transport header in gso_size. */
164 nh_off -= thlen;
165 break;
166 case SKB_GSO_UDP_L4:
167 if (!(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
168 return -EINVAL;
169 if (skb->csum_offset != offsetof(struct udphdr, check))
170 return -EINVAL;
171 if (skb->len - p_off > gso_size * UDP_MAX_SEGMENTS)
172 return -EINVAL;
173 if (gso_type != SKB_GSO_UDP_L4)
174 return -EINVAL;
175 break;
176 case SKB_GSO_TCPV4:
177 case SKB_GSO_TCPV6:
178 if (skb->ip_summed == CHECKSUM_PARTIAL &&
179 skb->csum_offset != offsetof(struct tcphdr, check))
180 return -EINVAL;
181 break;
182 }
183
184 /* Kernel has a special handling for GSO_BY_FRAGS. */
185 if (gso_size == GSO_BY_FRAGS)
186 return -EINVAL;
187
188 /* Too small packets are not really GSO ones. */
189 if (skb->len - nh_off > gso_size) {
190 shinfo->gso_size = gso_size;
191 shinfo->gso_type = gso_type;
192
193 /* Header must be checked, and gso_segs computed. */
194 shinfo->gso_type |= SKB_GSO_DODGY;
195 shinfo->gso_segs = 0;
196 }
197 }
198
199 return 0;
200 }
201
202 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
203 struct virtio_net_hdr *hdr,
204 bool little_endian,
205 bool has_data_valid,
206 int vlan_hlen)
207 {
208 memset(hdr, 0, sizeof(*hdr)); /* no info leak */
209
210 if (skb_is_gso(skb)) {
211 struct skb_shared_info *sinfo = skb_shinfo(skb);
212
213 /* This is a hint as to how much should be linear. */
214 hdr->hdr_len = __cpu_to_virtio16(little_endian,
215 skb_headlen(skb));
216 hdr->gso_size = __cpu_to_virtio16(little_endian,
217 sinfo->gso_size);
218 if (sinfo->gso_type & SKB_GSO_TCPV4)
219 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
220 else if (sinfo->gso_type & SKB_GSO_TCPV6)
221 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
222 else if (sinfo->gso_type & SKB_GSO_UDP_L4)
223 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4;
224 else
225 return -EINVAL;
226 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
227 hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
228 } else
229 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
230
231 if (skb->ip_summed == CHECKSUM_PARTIAL) {
232 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
233 hdr->csum_start = __cpu_to_virtio16(little_endian,
234 skb_checksum_start_offset(skb) + vlan_hlen);
235 hdr->csum_offset = __cpu_to_virtio16(little_endian,
236 skb->csum_offset);
237 } else if (has_data_valid &&
238 skb->ip_summed == CHECKSUM_UNNECESSARY) {
239 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
240 } /* else everything is zero */
241
242 return 0;
243 }
244
245 #endif /* _LINUX_VIRTIO_NET_H */
246
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