include/linux/virtio_net.h

   1 #ifndef _LINUX_VIRTIO_NET_H
   2 #define _LINUX_VIRTIO_NET_H
   3
   4 #include <linux/if_vlan.h>
   5 #include <uapi/linux/virtio_net.h>
   6
   7 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
   8                                         const struct virtio_net_hdr *hdr,
   9                                         bool little_endian)
  10 {
  11         unsigned short gso_type = 0;
  12
  13         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  14                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  15                 case VIRTIO_NET_HDR_GSO_TCPV4:
  16                         gso_type = SKB_GSO_TCPV4;
  17                         break;
  18                 case VIRTIO_NET_HDR_GSO_TCPV6:
  19                         gso_type = SKB_GSO_TCPV6;
  20                         break;
  21                 case VIRTIO_NET_HDR_GSO_UDP:
  22                         gso_type = SKB_GSO_UDP;
  23                         break;
  24                 default:
  25                         return -EINVAL;
  26                 }
  27
  28                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  29                         gso_type |= SKB_GSO_TCP_ECN;
  30
  31                 if (hdr->gso_size == 0)
  32                         return -EINVAL;
  33         }
  34
  35         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  36                 u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  37                 u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  38
  39                 if (!skb_partial_csum_set(skb, start, off))
  40                         return -EINVAL;
  41         }
  42
  43         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  44                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
  45
  46                 skb_shinfo(skb)->gso_size = gso_size;
  47                 skb_shinfo(skb)->gso_type = gso_type;
  48
  49                 /* Header must be checked, and gso_segs computed. */
  50                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
  51                 skb_shinfo(skb)->gso_segs = 0;
  52         }
  53
  54         return 0;
  55 }
  56
  57 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
  58                                           struct virtio_net_hdr *hdr,
  59                                           bool little_endian)
  60 {
  61         memset(hdr, 0, sizeof(*hdr));
  62
  63         if (skb_is_gso(skb)) {
  64                 struct skb_shared_info *sinfo = skb_shinfo(skb);
  65
  66                 /* This is a hint as to how much should be linear. */
  67                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
  68                                                  skb_headlen(skb));
  69                 hdr->gso_size = __cpu_to_virtio16(little_endian,
  70                                                   sinfo->gso_size);
  71                 if (sinfo->gso_type & SKB_GSO_TCPV4)
  72                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
  73                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
  74                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
  75                 else if (sinfo->gso_type & SKB_GSO_UDP)
  76                         hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
  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 (skb->ip_summed == CHECKSUM_UNNECESSARY) {
  95                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
  96         } /* else everything is zero */
  97
  98         return 0;
  99 }
 100
 101 #endif /* _LINUX_VIRTIO_BYTEORDER */