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