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 p_off = 0;
  35         unsigned int ip_proto;
  36
  37         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  38                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  39                 case VIRTIO_NET_HDR_GSO_TCPV4:
  40                         gso_type = SKB_GSO_TCPV4;
  41                         ip_proto = IPPROTO_TCP;
  42                         thlen = sizeof(struct tcphdr);
  43                         break;
  44                 case VIRTIO_NET_HDR_GSO_TCPV6:
  45                         gso_type = SKB_GSO_TCPV6;
  46                         ip_proto = IPPROTO_TCP;
  47                         thlen = sizeof(struct tcphdr);
  48                         break;
  49                 case VIRTIO_NET_HDR_GSO_UDP:
  50                         gso_type = SKB_GSO_UDP;
  51                         ip_proto = IPPROTO_UDP;
  52                         thlen = sizeof(struct udphdr);
  53                         break;
  54                 default:
  55                         return -EINVAL;
  56                 }
  57
  58                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  59                         gso_type |= SKB_GSO_TCP_ECN;
  60
  61                 if (hdr->gso_size == 0)
  62                         return -EINVAL;
  63         }
  64
  65         skb_reset_mac_header(skb);
  66
  67         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  68                 u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  69                 u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  70                 u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16));
  71
  72                 if (!pskb_may_pull(skb, needed))
  73                         return -EINVAL;
  74
  75                 if (!skb_partial_csum_set(skb, start, off))
  76                         return -EINVAL;
  77
  78                 p_off = skb_transport_offset(skb) + thlen;
  79                 if (!pskb_may_pull(skb, p_off))
  80                         return -EINVAL;
  81         } else {
  82                 /* gso packets without NEEDS_CSUM do not set transport_offset.
  83                  * probe and drop if does not match one of the above types.
  84                  */
  85                 if (gso_type && skb->network_header) {
  86                         struct flow_keys_basic keys;
  87
  88                         if (!skb->protocol) {
  89                                 __be16 protocol = dev_parse_header_protocol(skb);
  90
  91                                 virtio_net_hdr_set_proto(skb, hdr);
  92                                 if (protocol && protocol != skb->protocol)
  93                                         return -EINVAL;
  94                         }
  95 retry:
  96                         if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
  97                                                               NULL, 0, 0, 0,
  98                                                               0)) {
  99                                 /* UFO does not specify ipv4 or 6: try both */
 100                                 if (gso_type & SKB_GSO_UDP &&
 101                                     skb->protocol == htons(ETH_P_IP)) {
 102                                         skb->protocol = htons(ETH_P_IPV6);
 103                                         goto retry;
 104                                 }
 105                                 return -EINVAL;
 106                         }
 107
 108                         p_off = keys.control.thoff + thlen;
 109                         if (!pskb_may_pull(skb, p_off) ||
 110                             keys.basic.ip_proto != ip_proto)
 111                                 return -EINVAL;
 112
 113                         skb_set_transport_header(skb, keys.control.thoff);
 114                 } else if (gso_type) {
 115                         p_off = thlen;
 116                         if (!pskb_may_pull(skb, p_off))
 117                                 return -EINVAL;
 118                 }
 119         }
 120
 121         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 122                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
 123                 unsigned int nh_off = p_off;
 124                 struct skb_shared_info *shinfo = skb_shinfo(skb);
 125
 126                 /* UFO may not include transport header in gso_size. */
 127                 if (gso_type & SKB_GSO_UDP)
 128                         nh_off -= thlen;
 129
 130                 /* Too small packets are not really GSO ones. */
 131                 if (skb->len - nh_off > gso_size) {
 132                         shinfo->gso_size = gso_size;
 133                         shinfo->gso_type = gso_type;
 134
 135                         /* Header must be checked, and gso_segs computed. */
 136                         shinfo->gso_type |= SKB_GSO_DODGY;
 137                         shinfo->gso_segs = 0;
 138                 }
 139         }
 140
 141         return 0;
 142 }
 143
 144 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
 145                                           struct virtio_net_hdr *hdr,
 146                                           bool little_endian,
 147                                           bool has_data_valid,
 148                                           int vlan_hlen)
 149 {
 150         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
 151
 152         if (skb_is_gso(skb)) {
 153                 struct skb_shared_info *sinfo = skb_shinfo(skb);
 154
 155                 /* This is a hint as to how much should be linear. */
 156                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
 157                                                  skb_headlen(skb));
 158                 hdr->gso_size = __cpu_to_virtio16(little_endian,
 159                                                   sinfo->gso_size);
 160                 if (sinfo->gso_type & SKB_GSO_TCPV4)
 161                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 162                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
 163                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 164                 else
 165                         return -EINVAL;
 166                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 167                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 168         } else
 169                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 170
 171         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 172                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 173                 hdr->csum_start = __cpu_to_virtio16(little_endian,
 174                         skb_checksum_start_offset(skb) + vlan_hlen);
 175                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
 176                                 skb->csum_offset);
 177         } else if (has_data_valid &&
 178                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
 179                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
 180         } /* else everything is zero */
 181
 182         return 0;
 183 }
 184
 185 #endif /* _LINUX_VIRTIO_NET_H */