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 */ 207