include/linux/virtio_net.h

   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/virtio_net.h>
   7
   8 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
   9                                         const struct virtio_net_hdr *hdr,
  10                                         bool little_endian)
  11 {
  12         unsigned int gso_type = 0;
  13
  14         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  15                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  16                 case VIRTIO_NET_HDR_GSO_TCPV4:
  17                         gso_type = SKB_GSO_TCPV4;
  18                         break;
  19                 case VIRTIO_NET_HDR_GSO_TCPV6:
  20                         gso_type = SKB_GSO_TCPV6;
  21                         break;
  22                 case VIRTIO_NET_HDR_GSO_UDP:
  23                         gso_type = SKB_GSO_UDP;
  24                         break;
  25                 default:
  26                         return -EINVAL;
  27                 }
  28
  29                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  30                         gso_type |= SKB_GSO_TCP_ECN;
  31
  32                 if (hdr->gso_size == 0)
  33                         return -EINVAL;
  34         }
  35
  36         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  37                 u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  38                 u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  39
  40                 if (!skb_partial_csum_set(skb, start, off))
  41                         return -EINVAL;
  42         }
  43
  44         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  45                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
  46
  47                 skb_shinfo(skb)->gso_size = gso_size;
  48                 skb_shinfo(skb)->gso_type = gso_type;
  49
  50                 /* Header must be checked, and gso_segs computed. */
  51                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
  52                 skb_shinfo(skb)->gso_segs = 0;
  53         }
  54
  55         return 0;
  56 }
  57
  58 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
  59                                           struct virtio_net_hdr *hdr,
  60                                           bool little_endian,
  61                                           bool has_data_valid)
  62 {
  63         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
  64
  65         if (skb_is_gso(skb)) {
  66                 struct skb_shared_info *sinfo = skb_shinfo(skb);
  67
  68                 /* This is a hint as to how much should be linear. */
  69                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
  70                                                  skb_headlen(skb));
  71                 hdr->gso_size = __cpu_to_virtio16(little_endian,
  72                                                   sinfo->gso_size);
  73                 if (sinfo->gso_type & SKB_GSO_TCPV4)
  74                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
  75                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
  76                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
  77                 else
  78                         return -EINVAL;
  79                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
  80                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
  81         } else
  82                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
  83
  84         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  85                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
  86                 if (skb_vlan_tag_present(skb))
  87                         hdr->csum_start = __cpu_to_virtio16(little_endian,
  88                                 skb_checksum_start_offset(skb) + VLAN_HLEN);
  89                 else
  90                         hdr->csum_start = __cpu_to_virtio16(little_endian,
  91                                 skb_checksum_start_offset(skb));
  92                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
  93                                 skb->csum_offset);
  94         } else if (has_data_valid &&
  95                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
  96                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
  97         } /* else everything is zero */
  98
  99         return 0;
 100 }
 101
 102 #endif /* _LINUX_VIRTIO_NET_H */