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 bool virtio_net_hdr_match_proto(__be16 protocol, __u8 gso_type)
  11 {
  12         switch (gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  13         case VIRTIO_NET_HDR_GSO_TCPV4:
  14                 return protocol == cpu_to_be16(ETH_P_IP);
  15         case VIRTIO_NET_HDR_GSO_TCPV6:
  16                 return protocol == cpu_to_be16(ETH_P_IPV6);
  17         case VIRTIO_NET_HDR_GSO_UDP:
  18                 return protocol == cpu_to_be16(ETH_P_IP) ||
  19                        protocol == cpu_to_be16(ETH_P_IPV6);
  20         default:
  21                 return false;
  22         }
  23 }
  24
  25 static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
  26                                            const struct virtio_net_hdr *hdr)
  27 {
  28         if (skb->protocol)
  29                 return 0;
  30
  31         switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  32         case VIRTIO_NET_HDR_GSO_TCPV4:
  33         case VIRTIO_NET_HDR_GSO_UDP:
  34                 skb->protocol = cpu_to_be16(ETH_P_IP);
  35                 break;
  36         case VIRTIO_NET_HDR_GSO_TCPV6:
  37                 skb->protocol = cpu_to_be16(ETH_P_IPV6);
  38                 break;
  39         default:
  40                 return -EINVAL;
  41         }
  42
  43         return 0;
  44 }
  45
  46 static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
  47                                         const struct virtio_net_hdr *hdr,
  48                                         bool little_endian)
  49 {
  50         unsigned int gso_type = 0;
  51         unsigned int thlen = 0;
  52         unsigned int p_off = 0;
  53         unsigned int ip_proto;
  54
  55         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
  56                 switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
  57                 case VIRTIO_NET_HDR_GSO_TCPV4:
  58                         gso_type = SKB_GSO_TCPV4;
  59                         ip_proto = IPPROTO_TCP;
  60                         thlen = sizeof(struct tcphdr);
  61                         break;
  62                 case VIRTIO_NET_HDR_GSO_TCPV6:
  63                         gso_type = SKB_GSO_TCPV6;
  64                         ip_proto = IPPROTO_TCP;
  65                         thlen = sizeof(struct tcphdr);
  66                         break;
  67                 case VIRTIO_NET_HDR_GSO_UDP:
  68                         gso_type = SKB_GSO_UDP;
  69                         ip_proto = IPPROTO_UDP;
  70                         thlen = sizeof(struct udphdr);
  71                         break;
  72                 default:
  73                         return -EINVAL;
  74                 }
  75
  76                 if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
  77                         gso_type |= SKB_GSO_TCP_ECN;
  78
  79                 if (hdr->gso_size == 0)
  80                         return -EINVAL;
  81         }
  82
  83         skb_reset_mac_header(skb);
  84
  85         if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
  86                 u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start);
  87                 u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset);
  88                 u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16));
  89
  90                 if (!pskb_may_pull(skb, needed))
  91                         return -EINVAL;
  92
  93                 if (!skb_partial_csum_set(skb, start, off))
  94                         return -EINVAL;
  95
  96                 p_off = skb_transport_offset(skb) + thlen;
  97                 if (!pskb_may_pull(skb, p_off))
  98                         return -EINVAL;
  99         } else {
 100                 /* gso packets without NEEDS_CSUM do not set transport_offset.
 101                  * probe and drop if does not match one of the above types.
 102                  */
 103                 if (gso_type && skb->network_header) {
 104                         struct flow_keys_basic keys;
 105
 106                         if (!skb->protocol) {
 107                                 __be16 protocol = dev_parse_header_protocol(skb);
 108
 109                                 if (!protocol)
 110                                         virtio_net_hdr_set_proto(skb, hdr);
 111                                 else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))
 112                                         return -EINVAL;
 113                                 else
 114                                         skb->protocol = protocol;
 115                         }
 116 retry:
 117                         if (!skb_flow_dissect_flow_keys_basic(NULL, skb, &keys,
 118                                                               NULL, 0, 0, 0,
 119                                                               0)) {
 120                                 /* UFO does not specify ipv4 or 6: try both */
 121                                 if (gso_type & SKB_GSO_UDP &&
 122                                     skb->protocol == htons(ETH_P_IP)) {
 123                                         skb->protocol = htons(ETH_P_IPV6);
 124                                         goto retry;
 125                                 }
 126                                 return -EINVAL;
 127                         }
 128
 129                         p_off = keys.control.thoff + thlen;
 130                         if (!pskb_may_pull(skb, p_off) ||
 131                             keys.basic.ip_proto != ip_proto)
 132                                 return -EINVAL;
 133
 134                         skb_set_transport_header(skb, keys.control.thoff);
 135                 } else if (gso_type) {
 136                         p_off = thlen;
 137                         if (!pskb_may_pull(skb, p_off))
 138                                 return -EINVAL;
 139                 }
 140         }
 141
 142         if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 143                 u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
 144                 unsigned int nh_off = p_off;
 145                 struct skb_shared_info *shinfo = skb_shinfo(skb);
 146
 147                 /* UFO may not include transport header in gso_size. */
 148                 if (gso_type & SKB_GSO_UDP)
 149                         nh_off -= thlen;
 150
 151                 /* Too small packets are not really GSO ones. */
 152                 if (skb->len - nh_off > gso_size) {
 153                         shinfo->gso_size = gso_size;
 154                         shinfo->gso_type = gso_type;
 155
 156                         /* Header must be checked, and gso_segs computed. */
 157                         shinfo->gso_type |= SKB_GSO_DODGY;
 158                         shinfo->gso_segs = 0;
 159                 }
 160         }
 161
 162         return 0;
 163 }
 164
 165 static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
 166                                           struct virtio_net_hdr *hdr,
 167                                           bool little_endian,
 168                                           bool has_data_valid,
 169                                           int vlan_hlen)
 170 {
 171         memset(hdr, 0, sizeof(*hdr));   /* no info leak */
 172
 173         if (skb_is_gso(skb)) {
 174                 struct skb_shared_info *sinfo = skb_shinfo(skb);
 175
 176                 /* This is a hint as to how much should be linear. */
 177                 hdr->hdr_len = __cpu_to_virtio16(little_endian,
 178                                                  skb_headlen(skb));
 179                 hdr->gso_size = __cpu_to_virtio16(little_endian,
 180                                                   sinfo->gso_size);
 181                 if (sinfo->gso_type & SKB_GSO_TCPV4)
 182                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 183                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
 184                         hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 185                 else
 186                         return -EINVAL;
 187                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 188                         hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 189         } else
 190                 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 191
 192         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 193                 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 194                 hdr->csum_start = __cpu_to_virtio16(little_endian,
 195                         skb_checksum_start_offset(skb) + vlan_hlen);
 196                 hdr->csum_offset = __cpu_to_virtio16(little_endian,
 197                                 skb->csum_offset);
 198         } else if (has_data_valid &&
 199                    skb->ip_summed == CHECKSUM_UNNECESSARY) {
 200                 hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
 201         } /* else everything is zero */
 202
 203         return 0;
 204 }
 205
 206 #endif /* _LINUX_VIRTIO_NET_H */