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