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/tcp.h>
   7 #include <uapi/linux/udp.h>
   8 #include <uapi/linux/virtio_net.h>
   9
  10 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
  11                                            const struct virtio_net_hdr *hdr)
  12 {
  13         switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  14         case VIRTIO_NET_HDR_GSO_TCPV4:
  15         case VIRTIO_NET_HDR_GSO_UDP:
  16                 skb->protocol = cpu_to_be16(ETH_P_IP);
  17                 break;
  18         case VIRTIO_NET_HDR_GSO_TCPV6:
  19                 skb->protocol = cpu_to_be16(ETH_P_IPV6);
  20                 break;
  21         default:
  22                 return -EINVAL;
  23         }
  24
  25         return 0;
  26 }
  27
  28 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
  29                                         const struct virtio_net_hdr *hdr,
  30                                         bool little_endian)
  31 {
  32         unsigned int gso_type = 0;
  33         unsigned int thlen = 0;
  34         unsigned int ip_proto;
  35
  36         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  37                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  38                 case VIRTIO_NET_HDR_GSO_TCPV4:
  39                         gso_type = SKB_GSO_TCPV4;
  40                         ip_proto = IPPROTO_TCP;
  41                         thlen = sizeof(struct tcphdr);
  42                         break;
  43                 case VIRTIO_NET_HDR_GSO_TCPV6:
  44                         gso_type = SKB_GSO_TCPV6;
  45                         ip_proto = IPPROTO_TCP;
  46                         thlen = sizeof(struct tcphdr);
  47                         break;
  48                 case VIRTIO_NET_HDR_GSO_UDP:
  49                         gso_type = SKB_GSO_UDP;
  50                         ip_proto = IPPROTO_UDP;
  51                         thlen = sizeof(struct udphdr);
  52                         break;
  53                 default:
  54                         return -EINVAL;
  55                 }
  56
  57                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  58                         gso_type |= SKB_GSO_TCP_ECN;
  59
  60                 if (hdr->gso_size == 0)
  61                         return -EINVAL;
  62         }
  63
  64         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  65                 u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  66                 u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  67
  68                 if (!skb_partial_csum_set(skb, start, off))
  69                         return -EINVAL;
  70
  71                 if (skb_transport_offset(skb) + thlen > skb_headlen(skb))
  72                         return -EINVAL;
  73         } else {
  74                 /* gso packets without NEEDS_CSUM do not set transport_offset.
  75                  * probe and drop if does not match one of the above types.
  76                  */
  77                 if (gso_type && skb->network_header) {
  78                         struct flow_keys_basic keys;
  79
  80                         if (!skb->protocol)
  81                                 virtio_net_hdr_set_proto(skb, hdr);
  82 retry:
  83                         if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
  84                                                               NULL, 0, 0, 0,
  85                                                               0)) {
  86                                 /* UFO does not specify ipv4 or 6: try both */
  87                                 if (gso_type & SKB_GSO_UDP &&
  88                                     skb->protocol == htons(ETH_P_IP)) {
  89                                         skb->protocol = htons(ETH_P_IPV6);
  90                                         goto retry;
  91                                 }
  92                                 return -EINVAL;
  93                         }
  94
  95                         if (keys.control.thoff + thlen > skb_headlen(skb) ||
  96                             keys.basic.ip_proto != ip_proto)
  97                                 return -EINVAL;
  98
  99                         skb_set_transport_header(skb, keys.control.thoff);
 100                 }
 101         }
 102
 103         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 104                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
 105
 106                 skb_shinfo(skb)->gso_size = gso_size;
 107                 skb_shinfo(skb)->gso_type = gso_type;
 108
 109                 /* Header must be checked, and gso_segs computed. */
 110                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 111                 skb_shinfo(skb)->gso_segs = 0;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
 118                                           struct virtio_net_hdr *hdr,
 119                                           bool little_endian,
 120                                           bool has_data_valid,
 121                                           int vlan_hlen)
 122 {
 123         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
 124
 125         if (skb_is_gso(skb)) {
 126                 struct skb_shared_info *sinfo = skb_shinfo(skb);
 127
 128                 /* This is a hint as to how much should be linear. */
 129                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
 130                                                  skb_headlen(skb));
 131                 hdr->gso_size = __cpu_to_virtio16(little_endian,
 132                                                   sinfo->gso_size);
 133                 if (sinfo->gso_type & SKB_GSO_TCPV4)
 134                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 135                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
 136                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 137                 else
 138                         return -EINVAL;
 139                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 140                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 141         } else
 142                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 143
 144         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 145                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 146                 hdr->csum_start = __cpu_to_virtio16(little_endian,
 147                         skb_checksum_start_offset(skb) + vlan_hlen);
 148                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
 149                                 skb->csum_offset);
 150         } else if (has_data_valid &&
 151                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
 152                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
 153         } /* else everything is zero */
 154
 155         return 0;
 156 }
 157
 158 #endif /* _LINUX_VIRTIO_NET_H */