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 <uapi/linux/tcp.h>
7 #include <uapi/linux/udp.h>
8 #include <uapi/linux/virtio_net.h>
9
virtio_net_hdr_set_proto(struct sk_buff * skb,const struct virtio_net_hdr * hdr)10 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
11 const struct virtio_net_hdr *hdr)
12 {
13 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
14 case VIRTIO_NET_HDR_GSO_TCPV4:
15 case VIRTIO_NET_HDR_GSO_UDP:
16 skb->protocol = cpu_to_be16(ETH_P_IP);
17 break;
18 case VIRTIO_NET_HDR_GSO_TCPV6:
19 skb->protocol = cpu_to_be16(ETH_P_IPV6);
20 break;
21 default:
22 return -EINVAL;
23 }
24
25 return 0;
26 }
27
virtio_net_hdr_to_skb(struct sk_buff * skb,const struct virtio_net_hdr * hdr,bool little_endian)28 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
29 const struct virtio_net_hdr *hdr,
30 bool little_endian)
31 {
32 unsigned int gso_type = 0;
33 unsigned int thlen = 0;
34 unsigned int p_off = 0;
35 unsigned int ip_proto;
36
37 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
38 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
39 case VIRTIO_NET_HDR_GSO_TCPV4:
40 gso_type = SKB_GSO_TCPV4;
41 ip_proto = IPPROTO_TCP;
42 thlen = sizeof(struct tcphdr);
43 break;
44 case VIRTIO_NET_HDR_GSO_TCPV6:
45 gso_type = SKB_GSO_TCPV6;
46 ip_proto = IPPROTO_TCP;
47 thlen = sizeof(struct tcphdr);
48 break;
49 case VIRTIO_NET_HDR_GSO_UDP:
50 gso_type = SKB_GSO_UDP;
51 ip_proto = IPPROTO_UDP;
52 thlen = sizeof(struct udphdr);
53 break;
54 default:
55 return -EINVAL;
56 }
57
58 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
59 gso_type |= SKB_GSO_TCP_ECN;
60
61 if (hdr->gso_size == 0)
62 return -EINVAL;
63 }
64
65 skb_reset_mac_header(skb);
66
67 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
68 u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
69 u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
70 u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16));
71
72 if (!pskb_may_pull(skb, needed))
73 return -EINVAL;
74
75 if (!skb_partial_csum_set(skb, start, off))
76 return -EINVAL;
77
78 p_off = skb_transport_offset(skb) + thlen;
79 if (!pskb_may_pull(skb, p_off))
80 return -EINVAL;
81 } else {
82 /* gso packets without NEEDS_CSUM do not set transport_offset.
83 * probe and drop if does not match one of the above types.
84 */
85 if (gso_type && skb->network_header) {
86 struct flow_keys_basic keys;
87
88 if (!skb->protocol) {
89 __be16 protocol = dev_parse_header_protocol(skb);
90
91 virtio_net_hdr_set_proto(skb, hdr);
92 if (protocol && protocol != skb->protocol)
93 return -EINVAL;
94 }
95 retry:
96 if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
97 NULL, 0, 0, 0,
98 0)) {
99 /* UFO does not specify ipv4 or 6: try both */
100 if (gso_type & SKB_GSO_UDP &&
101 skb->protocol == htons(ETH_P_IP)) {
102 skb->protocol = htons(ETH_P_IPV6);
103 goto retry;
104 }
105 return -EINVAL;
106 }
107
108 p_off = keys.control.thoff + thlen;
109 if (!pskb_may_pull(skb, p_off) ||
110 keys.basic.ip_proto != ip_proto)
111 return -EINVAL;
112
113 skb_set_transport_header(skb, keys.control.thoff);
114 } else if (gso_type) {
115 p_off = thlen;
116 if (!pskb_may_pull(skb, p_off))
117 return -EINVAL;
118 }
119 }
120
121 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
122 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
123 struct skb_shared_info *shinfo = skb_shinfo(skb);
124
125 /* Too small packets are not really GSO ones. */
126 if (skb->len - p_off > gso_size) {
127 shinfo->gso_size = gso_size;
128 shinfo->gso_type = gso_type;
129
130 /* Header must be checked, and gso_segs computed. */
131 shinfo->gso_type |= SKB_GSO_DODGY;
132 shinfo->gso_segs = 0;
133 }
134 }
135
136 return 0;
137 }
138
virtio_net_hdr_from_skb(const struct sk_buff * skb,struct virtio_net_hdr * hdr,bool little_endian,bool has_data_valid,int vlan_hlen)139 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
140 struct virtio_net_hdr *hdr,
141 bool little_endian,
142 bool has_data_valid,
143 int vlan_hlen)
144 {
145 memset(hdr, 0, sizeof(*hdr)); /* no info leak */
146
147 if (skb_is_gso(skb)) {
148 struct skb_shared_info *sinfo = skb_shinfo(skb);
149
150 /* This is a hint as to how much should be linear. */
151 hdr->hdr_len = __cpu_to_virtio16(little_endian,
152 skb_headlen(skb));
153 hdr->gso_size = __cpu_to_virtio16(little_endian,
154 sinfo->gso_size);
155 if (sinfo->gso_type & SKB_GSO_TCPV4)
156 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
157 else if (sinfo->gso_type & SKB_GSO_TCPV6)
158 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
159 else
160 return -EINVAL;
161 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
162 hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
163 } else
164 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
165
166 if (skb->ip_summed == CHECKSUM_PARTIAL) {
167 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
168 hdr->csum_start = __cpu_to_virtio16(little_endian,
169 skb_checksum_start_offset(skb) + vlan_hlen);
170 hdr->csum_offset = __cpu_to_virtio16(little_endian,
171 skb->csum_offset);
172 } else if (has_data_valid &&
173 skb->ip_summed == CHECKSUM_UNNECESSARY) {
174 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
175 } /* else everything is zero */
176
177 return 0;
178 }
179
180 #endif /* _LINUX_VIRTIO_NET_H */
181