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                                           int vlan_hlen)
  63 {
  64         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
  65
  66         if (skb_is_gso(skb)) {
  67                 struct skb_shared_info *sinfo = skb_shinfo(skb);
  68
  69                 /* This is a hint as to how much should be linear. */
  70                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
  71                                                  skb_headlen(skb));
  72                 hdr->gso_size = __cpu_to_virtio16(little_endian,
  73                                                   sinfo->gso_size);
  74                 if (sinfo->gso_type & SKB_GSO_TCPV4)
  75                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
  76                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
  77                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
  78                 else
  79                         return -EINVAL;
  80                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
  81                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
  82         } else
  83                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
  84
  85         if (skb->ip_summed == CHECKSUM_PARTIAL) {
  86                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
  87                 hdr->csum_start = __cpu_to_virtio16(little_endian,
  88                         skb_checksum_start_offset(skb) + vlan_hlen);
  89                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
  90                                 skb->csum_offset);
  91         } else if (has_data_valid &&
  92                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
  93                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
  94         } /* else everything is zero */
  95
  96         return 0;
  97 }
  98
  99 #endif /* _LINUX_VIRTIO_NET_H */