1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_NET_H
3 #define _LINUX_VIRTIO_NET_H
5 #include <linux/if_vlan.h>
7 #include <linux/ipv6.h>
9 #include <uapi/linux/tcp.h>
10 #include <uapi/linux/virtio_net.h>
12 static inline bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type)
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);
28 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
29 const struct virtio_net_hdr *hdr)
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);
40 case VIRTIO_NET_HDR_GSO_TCPV6:
41 skb->protocol = cpu_to_be16(ETH_P_IPV6);
50 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
51 const struct virtio_net_hdr *hdr,
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;
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);
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);
73 case VIRTIO_NET_HDR_GSO_UDP:
74 gso_type = SKB_GSO_UDP;
75 ip_proto = IPPROTO_UDP;
76 thlen = sizeof(struct udphdr);
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);
87 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
88 gso_type |= SKB_GSO_TCP_ECN;
90 if (hdr->gso_size == 0)
94 skb_reset_mac_header(skb);
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));
101 if (!pskb_may_pull(skb, needed))
104 if (!skb_partial_csum_set(skb, start, off))
107 nh_min_len = max_t(u32, nh_min_len, skb_transport_offset(skb));
108 p_off = nh_min_len + thlen;
109 if (!pskb_may_pull(skb, p_off))
112 /* gso packets without NEEDS_CSUM do not set transport_offset.
113 * probe and drop if does not match one of the above types.
115 if (gso_type && skb->network_header) {
116 struct flow_keys_basic keys;
118 if (!skb->protocol) {
119 __be16 protocol = dev_parse_header_protocol(skb);
122 virtio_net_hdr_set_proto(skb, hdr);
123 else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))
126 skb->protocol = protocol;
129 if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
132 /* UFO does not specify ipv4 or 6: try both */
133 if (gso_type & SKB_GSO_UDP &&
134 skb->protocol == htons(ETH_P_IP)) {
135 skb->protocol = htons(ETH_P_IPV6);
141 p_off = keys.control.thoff + thlen;
142 if (!pskb_may_pull(skb, p_off) ||
143 keys.basic.ip_proto != ip_proto)
146 skb_set_transport_header(skb, keys.control.thoff);
147 } else if (gso_type) {
148 p_off = nh_min_len + thlen;
149 if (!pskb_may_pull(skb, p_off))
154 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
155 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
156 unsigned int nh_off = p_off;
157 struct skb_shared_info *shinfo = skb_shinfo(skb);
159 switch (gso_type & ~SKB_GSO_TCP_ECN) {
161 /* UFO may not include transport header in gso_size. */
165 if (!(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
167 if (skb->csum_offset != offsetof(struct udphdr, check))
169 if (skb->len - p_off > gso_size * UDP_MAX_SEGMENTS)
171 if (gso_type != SKB_GSO_UDP_L4)
176 if (skb->ip_summed == CHECKSUM_PARTIAL &&
177 skb->csum_offset != offsetof(struct tcphdr, check))
182 /* Kernel has a special handling for GSO_BY_FRAGS. */
183 if (gso_size == GSO_BY_FRAGS)
186 /* Too small packets are not really GSO ones. */
187 if (skb->len - nh_off > gso_size) {
188 shinfo->gso_size = gso_size;
189 shinfo->gso_type = gso_type;
191 /* Header must be checked, and gso_segs computed. */
192 shinfo->gso_type |= SKB_GSO_DODGY;
193 shinfo->gso_segs = 0;
200 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
201 struct virtio_net_hdr *hdr,
206 memset(hdr, 0, sizeof(*hdr)); /* no info leak */
208 if (skb_is_gso(skb)) {
209 struct skb_shared_info *sinfo = skb_shinfo(skb);
211 /* This is a hint as to how much should be linear. */
212 hdr->hdr_len = __cpu_to_virtio16(little_endian,
214 hdr->gso_size = __cpu_to_virtio16(little_endian,
216 if (sinfo->gso_type & SKB_GSO_TCPV4)
217 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
218 else if (sinfo->gso_type & SKB_GSO_TCPV6)
219 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
220 else if (sinfo->gso_type & SKB_GSO_UDP_L4)
221 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4;
224 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
225 hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
227 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
229 if (skb->ip_summed == CHECKSUM_PARTIAL) {
230 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
231 hdr->csum_start = __cpu_to_virtio16(little_endian,
232 skb_checksum_start_offset(skb) + vlan_hlen);
233 hdr->csum_offset = __cpu_to_virtio16(little_endian,
235 } else if (has_data_valid &&
236 skb->ip_summed == CHECKSUM_UNNECESSARY) {
237 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
238 } /* else everything is zero */
243 #endif /* _LINUX_VIRTIO_NET_H */