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_set_proto(struct sk_buff *skb,
   9                                            const struct virtio_net_hdr *hdr)
  10 {
  11         switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  12         case VIRTIO_NET_HDR_GSO_TCPV4:
  13         case VIRTIO_NET_HDR_GSO_UDP:
  14                 skb->protocol = cpu_to_be16(ETH_P_IP);
  15                 break;
  16         case VIRTIO_NET_HDR_GSO_TCPV6:
  17                 skb->protocol = cpu_to_be16(ETH_P_IPV6);
  18                 break;
  19         default:
  20                 return -EINVAL;
  21         }
  22
  23         return 0;
  24 }
  25
  26 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
  27                                         const struct virtio_net_hdr *hdr,
  28                                         bool little_endian)
  29 {
  30         unsigned int gso_type = 0;
  31
  32         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  33                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  34                 case VIRTIO_NET_HDR_GSO_TCPV4:
  35                         gso_type = SKB_GSO_TCPV4;
  36                         break;
  37                 case VIRTIO_NET_HDR_GSO_TCPV6:
  38                         gso_type = SKB_GSO_TCPV6;
  39                         break;
  40                 case VIRTIO_NET_HDR_GSO_UDP:
  41                         gso_type = SKB_GSO_UDP;
  42                         break;
  43                 default:
  44                         return -EINVAL;
  45                 }
  46
  47                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  48                         gso_type |= SKB_GSO_TCP_ECN;
  49
  50                 if (hdr->gso_size == 0)
  51                         return -EINVAL;
  52         }
  53
  54         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  55                 u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  56                 u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  57
  58                 if (!skb_partial_csum_set(skb, start, off))
  59                         return -EINVAL;
  60         } else {
  61                 /* gso packets without NEEDS_CSUM do not set transport_offset.
  62                  * probe and drop if does not match one of the above types.
  63                  */
  64                 if (gso_type && skb->network_header) {
  65                         if (!skb->protocol)
  66                                 virtio_net_hdr_set_proto(skb, hdr);
  67 retry:
  68                         skb_probe_transport_header(skb);
  69                         if (!skb_transport_header_was_set(skb)) {
  70                                 /* UFO does not specify ipv4 or 6: try both */
  71                                 if (gso_type & SKB_GSO_UDP &&
  72                                     skb->protocol == htons(ETH_P_IP)) {
  73                                         skb->protocol = htons(ETH_P_IPV6);
  74                                         goto retry;
  75                                 }
  76                                 return -EINVAL;
  77                         }
  78                 }
  79         }
  80
  81         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  82                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
  83
  84                 skb_shinfo(skb)->gso_size = gso_size;
  85                 skb_shinfo(skb)->gso_type = gso_type;
  86
  87                 /* Header must be checked, and gso_segs computed. */
  88                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
  89                 skb_shinfo(skb)->gso_segs = 0;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
  96                                           struct virtio_net_hdr *hdr,
  97                                           bool little_endian,
  98                                           bool has_data_valid,
  99                                           int vlan_hlen)
 100 {
 101         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
 102
 103         if (skb_is_gso(skb)) {
 104                 struct skb_shared_info *sinfo = skb_shinfo(skb);
 105
 106                 /* This is a hint as to how much should be linear. */
 107                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
 108                                                  skb_headlen(skb));
 109                 hdr->gso_size = __cpu_to_virtio16(little_endian,
 110                                                   sinfo->gso_size);
 111                 if (sinfo->gso_type & SKB_GSO_TCPV4)
 112                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 113                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
 114                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 115                 else
 116                         return -EINVAL;
 117                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 118                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 119         } else
 120                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 121
 122         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 123                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 124                 hdr->csum_start = __cpu_to_virtio16(little_endian,
 125                         skb_checksum_start_offset(skb) + vlan_hlen);
 126                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
 127                                 skb->csum_offset);
 128         } else if (has_data_valid &&
 129                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
 130                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
 131         } /* else everything is zero */
 132
 133         return 0;
 134 }
 135
 136 #endif /* _LINUX_VIRTIO_NET_H */