1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * This header is BSD licensed so anyone can use the definitions to implement 5 * compatible drivers/servers. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of IBM nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #ifndef _VIRTIO_NET_H 32 #define _VIRTIO_NET_H 33 34 /* The feature bitmap for virtio net */ 35 #define VIRTIO_NET_F_CSUM 0x000001 /* Host handles pkts w/ partial csum */ 36 #define VIRTIO_NET_F_GUEST_CSUM 0x000002 /* Guest handles pkts w/ partial csum*/ 37 #define VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 0x000004 /* Dynamic offload configuration. */ 38 #define VIRTIO_NET_F_MTU 0x000008 /* Initial MTU advice */ 39 #define VIRTIO_NET_F_MAC 0x000020 /* Host has given MAC address. */ 40 #define VIRTIO_NET_F_GSO 0x000040 /* Host handles pkts w/ any GSO type */ 41 #define VIRTIO_NET_F_GUEST_TSO4 0x000080 /* Guest can handle TSOv4 in. */ 42 #define VIRTIO_NET_F_GUEST_TSO6 0x000100 /* Guest can handle TSOv6 in. */ 43 #define VIRTIO_NET_F_GUEST_ECN 0x000200 /* Guest can handle TSO[6] w/ ECN in. */ 44 #define VIRTIO_NET_F_GUEST_UFO 0x000400 /* Guest can handle UFO in. */ 45 #define VIRTIO_NET_F_HOST_TSO4 0x000800 /* Host can handle TSOv4 in. */ 46 #define VIRTIO_NET_F_HOST_TSO6 0x001000 /* Host can handle TSOv6 in. */ 47 #define VIRTIO_NET_F_HOST_ECN 0x002000 /* Host can handle TSO[6] w/ ECN in. */ 48 #define VIRTIO_NET_F_HOST_UFO 0x004000 /* Host can handle UFO in. */ 49 #define VIRTIO_NET_F_MRG_RXBUF 0x008000 /* Host can merge receive buffers. */ 50 #define VIRTIO_NET_F_STATUS 0x010000 /* virtio_net_config.status available*/ 51 #define VIRTIO_NET_F_CTRL_VQ 0x020000 /* Control channel available */ 52 #define VIRTIO_NET_F_CTRL_RX 0x040000 /* Control channel RX mode support */ 53 #define VIRTIO_NET_F_CTRL_VLAN 0x080000 /* Control channel VLAN filtering */ 54 #define VIRTIO_NET_F_CTRL_RX_EXTRA 0x100000 /* Extra RX mode control support */ 55 #define VIRTIO_NET_F_GUEST_ANNOUNCE 0x200000 /* Announce device on network */ 56 #define VIRTIO_NET_F_MQ 0x400000 /* Device supports Receive Flow Steering */ 57 #define VIRTIO_NET_F_CTRL_MAC_ADDR 0x800000 /* Set MAC address */ 58 #define VIRTIO_NET_F_SPEED_DUPLEX (1ULL << 63) /* Device set linkspeed and duplex */ 59 60 #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */ 61 #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */ 62 63 struct virtio_net_config { 64 /* The config defining mac address (if VIRTIO_NET_F_MAC) */ 65 uint8_t mac[ETHER_ADDR_LEN]; 66 /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */ 67 uint16_t status; 68 /* Maximum number of each of transmit and receive queues; 69 * see VIRTIO_NET_F_MQ and VIRTIO_NET_CTRL_MQ. 70 * Legal values are between 1 and 0x8000. 71 */ 72 uint16_t max_virtqueue_pairs; 73 /* Default maximum transmit unit advice */ 74 uint16_t mtu; 75 /* 76 * speed, in units of 1Mb. All values 0 to INT_MAX are legal. 77 * Any other value stands for unknown. 78 */ 79 uint32_t speed; 80 /* 81 * 0x00 - half duplex 82 * 0x01 - full duplex 83 * Any other value stands for unknown. 84 */ 85 uint8_t duplex; 86 } __packed; 87 88 /* 89 * This header comes first in the scatter-gather list. If you don't 90 * specify GSO or CSUM features, you can simply ignore the header. 91 * 92 * This is bitwise-equivalent to the legacy struct virtio_net_hdr_mrg_rxbuf, 93 * only flattened. 94 */ 95 struct virtio_net_hdr_v1 { 96 #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */ 97 #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */ 98 uint8_t flags; 99 #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */ 100 #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */ 101 #define VIRTIO_NET_HDR_GSO_UDP 3 /* GSO frame, IPv4 UDP (UFO) */ 102 #define VIRTIO_NET_HDR_GSO_TCPV6 4 /* GSO frame, IPv6 TCP */ 103 #define VIRTIO_NET_HDR_GSO_ECN 0x80 /* TCP has ECN set */ 104 uint8_t gso_type; 105 uint16_t hdr_len; /* Ethernet + IP + tcp/udp hdrs */ 106 uint16_t gso_size; /* Bytes to append to hdr_len per frame */ 107 uint16_t csum_start; /* Position to start checksumming from */ 108 uint16_t csum_offset; /* Offset after that to place checksum */ 109 uint16_t num_buffers; /* Number of merged rx buffers */ 110 }; 111 112 /* 113 * This header comes first in the scatter-gather list. 114 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must 115 * be the first element of the scatter-gather list. If you don't 116 * specify GSO or CSUM features, you can simply ignore the header. 117 */ 118 struct virtio_net_hdr { 119 /* See VIRTIO_NET_HDR_F_* */ 120 uint8_t flags; 121 /* See VIRTIO_NET_HDR_GSO_* */ 122 uint8_t gso_type; 123 uint16_t hdr_len; /* Ethernet + IP + tcp/udp hdrs */ 124 uint16_t gso_size; /* Bytes to append to hdr_len per frame */ 125 uint16_t csum_start; /* Position to start checksumming from */ 126 uint16_t csum_offset; /* Offset after that to place checksum */ 127 }; 128 129 /* 130 * This is the version of the header to use when the MRG_RXBUF 131 * feature has been negotiated. 132 */ 133 struct virtio_net_hdr_mrg_rxbuf { 134 struct virtio_net_hdr hdr; 135 uint16_t num_buffers; /* Number of merged rx buffers */ 136 }; 137 138 /* 139 * Control virtqueue data structures 140 * 141 * The control virtqueue expects a header in the first sg entry 142 * and an ack/status response in the last entry. Data for the 143 * command goes in between. 144 */ 145 struct virtio_net_ctrl_hdr { 146 uint8_t class; 147 uint8_t cmd; 148 } __packed; 149 150 #define VIRTIO_NET_OK 0 151 #define VIRTIO_NET_ERR 1 152 153 /* 154 * Control the RX mode, ie. promiscuous, allmulti, etc... 155 * All commands require an "out" sg entry containing a 1 byte 156 * state value, zero = disable, non-zero = enable. Commands 157 * 0 and 1 are supported with the VIRTIO_NET_F_CTRL_RX feature. 158 * Commands 2-5 are added with VIRTIO_NET_F_CTRL_RX_EXTRA. 159 */ 160 #define VIRTIO_NET_CTRL_RX 0 161 #define VIRTIO_NET_CTRL_RX_PROMISC 0 162 #define VIRTIO_NET_CTRL_RX_ALLMULTI 1 163 #define VIRTIO_NET_CTRL_RX_ALLUNI 2 164 #define VIRTIO_NET_CTRL_RX_NOMULTI 3 165 #define VIRTIO_NET_CTRL_RX_NOUNI 4 166 #define VIRTIO_NET_CTRL_RX_NOBCAST 5 167 168 /* 169 * Control the MAC filter table. 170 * 171 * The MAC filter table is managed by the hypervisor, the guest should 172 * assume the size is infinite. Filtering should be considered 173 * non-perfect, ie. based on hypervisor resources, the guest may 174 * received packets from sources not specified in the filter list. 175 * 176 * In addition to the class/cmd header, the TABLE_SET command requires 177 * two out scatterlists. Each contains a 4 byte count of entries followed 178 * by a concatenated byte stream of the ETH_ALEN MAC addresses. The 179 * first sg list contains unicast addresses, the second is for multicast. 180 * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature 181 * is available. 182 * 183 * The ADDR_SET command requests one out scatterlist, it contains a 184 * 6 bytes MAC address. This functionality is present if the 185 * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available. 186 */ 187 struct virtio_net_ctrl_mac { 188 uint32_t entries; 189 uint8_t macs[][ETHER_ADDR_LEN]; 190 } __packed; 191 192 #define VIRTIO_NET_CTRL_MAC 1 193 #define VIRTIO_NET_CTRL_MAC_TABLE_SET 0 194 #define VIRTIO_NET_CTRL_MAC_ADDR_SET 1 195 196 /* 197 * Control VLAN filtering 198 * 199 * The VLAN filter table is controlled via a simple ADD/DEL interface. 200 * VLAN IDs not added may be filtered by the hypervisor. Del is the 201 * opposite of add. Both commands expect an out entry containing a 2 202 * byte VLAN ID. VLAN filtering is available with the 203 * VIRTIO_NET_F_CTRL_VLAN feature bit. 204 */ 205 #define VIRTIO_NET_CTRL_VLAN 2 206 #define VIRTIO_NET_CTRL_VLAN_ADD 0 207 #define VIRTIO_NET_CTRL_VLAN_DEL 1 208 209 /* 210 * Control link announce acknowledgement 211 * 212 * The command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that 213 * driver has recevied the notification; device would clear the 214 * VIRTIO_NET_S_ANNOUNCE bit in the status field after it receives 215 * this command. 216 */ 217 #define VIRTIO_NET_CTRL_ANNOUNCE 3 218 #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0 219 220 /* 221 * Control Receive Flow Steering 222 * 223 * The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET enables Receive Flow 224 * Steering, specifying the number of the transmit and receive queues 225 * that will be used. After the command is consumed and acked by the 226 * device, the device will not steer new packets on receive virtqueues 227 * other than specified nor read from transmit virtqueues other than 228 * specified. Accordingly, driver should not transmit new packets on 229 * virtqueues other than specified. 230 */ 231 struct virtio_net_ctrl_mq { 232 uint16_t virtqueue_pairs; 233 } __packed; 234 235 #define VIRTIO_NET_CTRL_MQ 4 236 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET 0 237 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 238 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 239 240 /* 241 * Control network offloads 242 * 243 * Reconfigures the network offloads that Guest can handle. 244 * 245 * Available with the VIRTIO_NET_F_CTRL_GUEST_OFFLOADS feature bit. 246 * 247 * Command data format matches the feature bit mask exactly. 248 * 249 * See VIRTIO_NET_F_GUEST_* for the list of offloads 250 * that can be enabled/disabled. 251 */ 252 #define VIRTIO_NET_CTRL_GUEST_OFFLOADS 5 253 #define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET 0 254 255 /* 256 * Use the checksum offset in the VirtIO header to set the 257 * correct CSUM_* flags. 258 */ 259 static inline int 260 virtio_net_rx_csum_by_offset(struct mbuf *m, uint16_t eth_type, int ip_start, 261 struct virtio_net_hdr *hdr) 262 { 263 #if defined(INET) || defined(INET6) 264 int offset = hdr->csum_start + hdr->csum_offset; 265 #endif 266 267 /* Only do a basic sanity check on the offset. */ 268 switch (eth_type) { 269 #if defined(INET) 270 case ETHERTYPE_IP: 271 if (__predict_false(offset < ip_start + sizeof(struct ip))) 272 return (1); 273 break; 274 #endif 275 #if defined(INET6) 276 case ETHERTYPE_IPV6: 277 if (__predict_false(offset < ip_start + sizeof(struct ip6_hdr))) 278 return (1); 279 break; 280 #endif 281 default: 282 /* Here we should increment the rx_csum_bad_ethtype counter. */ 283 return (1); 284 } 285 286 /* 287 * Use the offset to determine the appropriate CSUM_* flags. This is 288 * a bit dirty, but we can get by with it since the checksum offsets 289 * happen to be different. We assume the host host does not do IPv4 290 * header checksum offloading. 291 */ 292 switch (hdr->csum_offset) { 293 case offsetof(struct udphdr, uh_sum): 294 case offsetof(struct tcphdr, th_sum): 295 m->m_pkthdr.csum_flags |= CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 296 m->m_pkthdr.csum_data = 0xFFFF; 297 break; 298 default: 299 /* Here we should increment the rx_csum_bad_offset counter. */ 300 return (1); 301 } 302 303 return (0); 304 } 305 306 static inline int 307 virtio_net_rx_csum_by_parse(struct mbuf *m, uint16_t eth_type, int ip_start, 308 struct virtio_net_hdr *hdr) 309 { 310 int offset, proto; 311 312 switch (eth_type) { 313 #if defined(INET) 314 case ETHERTYPE_IP: { 315 struct ip *ip; 316 if (__predict_false(m->m_len < ip_start + sizeof(struct ip))) 317 return (1); 318 ip = (struct ip *)(m->m_data + ip_start); 319 proto = ip->ip_p; 320 offset = ip_start + (ip->ip_hl << 2); 321 break; 322 } 323 #endif 324 #if defined(INET6) 325 case ETHERTYPE_IPV6: 326 if (__predict_false(m->m_len < ip_start + 327 sizeof(struct ip6_hdr))) 328 return (1); 329 offset = ip6_lasthdr(m, ip_start, IPPROTO_IPV6, &proto); 330 if (__predict_false(offset < 0)) 331 return (1); 332 break; 333 #endif 334 default: 335 /* Here we should increment the rx_csum_bad_ethtype counter. */ 336 return (1); 337 } 338 339 switch (proto) { 340 case IPPROTO_TCP: 341 if (__predict_false(m->m_len < offset + sizeof(struct tcphdr))) 342 return (1); 343 m->m_pkthdr.csum_flags |= CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 344 m->m_pkthdr.csum_data = 0xFFFF; 345 break; 346 case IPPROTO_UDP: 347 if (__predict_false(m->m_len < offset + sizeof(struct udphdr))) 348 return (1); 349 m->m_pkthdr.csum_flags |= CSUM_DATA_VALID | CSUM_PSEUDO_HDR; 350 m->m_pkthdr.csum_data = 0xFFFF; 351 break; 352 default: 353 /* 354 * For the remaining protocols, FreeBSD does not support 355 * checksum offloading, so the checksum will be recomputed. 356 */ 357 #if 0 358 if_printf(ifp, "cksum offload of unsupported " 359 "protocol eth_type=%#x proto=%d csum_start=%d " 360 "csum_offset=%d\n", __func__, eth_type, proto, 361 hdr->csum_start, hdr->csum_offset); 362 #endif 363 break; 364 } 365 366 return (0); 367 } 368 369 /* 370 * Set the appropriate CSUM_* flags. Unfortunately, the information 371 * provided is not directly useful to us. The VirtIO header gives the 372 * offset of the checksum, which is all Linux needs, but this is not 373 * how FreeBSD does things. We are forced to peek inside the packet 374 * a bit. 375 * 376 * It would be nice if VirtIO gave us the L4 protocol or if FreeBSD 377 * could accept the offsets and let the stack figure it out. 378 */ 379 static inline int 380 virtio_net_rx_csum(struct mbuf *m, struct virtio_net_hdr *hdr) 381 { 382 struct ether_header *eh; 383 struct ether_vlan_header *evh; 384 uint16_t eth_type; 385 int offset, error; 386 387 if ((hdr->flags & (VIRTIO_NET_HDR_F_NEEDS_CSUM | 388 VIRTIO_NET_HDR_F_DATA_VALID)) == 0) { 389 return (0); 390 } 391 392 eh = mtod(m, struct ether_header *); 393 eth_type = ntohs(eh->ether_type); 394 if (eth_type == ETHERTYPE_VLAN) { 395 /* BMV: We should handle nested VLAN tags too. */ 396 evh = mtod(m, struct ether_vlan_header *); 397 eth_type = ntohs(evh->evl_proto); 398 offset = sizeof(struct ether_vlan_header); 399 } else 400 offset = sizeof(struct ether_header); 401 402 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) 403 error = virtio_net_rx_csum_by_offset(m, eth_type, offset, hdr); 404 else 405 error = virtio_net_rx_csum_by_parse(m, eth_type, offset, hdr); 406 407 return (error); 408 } 409 410 static inline int 411 virtio_net_tx_offload_ctx(struct mbuf *m, int *etype, int *proto, int *start) 412 { 413 struct ether_vlan_header *evh; 414 #if defined(INET) || defined(INET6) 415 int offset; 416 #endif 417 418 evh = mtod(m, struct ether_vlan_header *); 419 if (evh->evl_encap_proto == htons(ETHERTYPE_VLAN)) { 420 /* BMV: We should handle nested VLAN tags too. */ 421 *etype = ntohs(evh->evl_proto); 422 #if defined(INET) || defined(INET6) 423 offset = sizeof(struct ether_vlan_header); 424 #endif 425 } else { 426 *etype = ntohs(evh->evl_encap_proto); 427 #if defined(INET) || defined(INET6) 428 offset = sizeof(struct ether_header); 429 #endif 430 } 431 432 switch (*etype) { 433 #if defined(INET) 434 case ETHERTYPE_IP: { 435 struct ip *ip, iphdr; 436 if (__predict_false(m->m_len < offset + sizeof(struct ip))) { 437 m_copydata(m, offset, sizeof(struct ip), 438 (caddr_t) &iphdr); 439 ip = &iphdr; 440 } else 441 ip = (struct ip *)(m->m_data + offset); 442 *proto = ip->ip_p; 443 *start = offset + (ip->ip_hl << 2); 444 break; 445 } 446 #endif 447 #if defined(INET6) 448 case ETHERTYPE_IPV6: 449 *proto = -1; 450 *start = ip6_lasthdr(m, offset, IPPROTO_IPV6, proto); 451 /* Assert the network stack sent us a valid packet. */ 452 KASSERT(*start > offset, 453 ("%s: mbuf %p start %d offset %d proto %d", __func__, m, 454 *start, offset, *proto)); 455 break; 456 #endif 457 default: 458 /* Here we should increment the tx_csum_bad_ethtype counter. */ 459 return (EINVAL); 460 } 461 462 return (0); 463 } 464 465 static inline int 466 virtio_net_tx_offload_tso(if_t ifp, struct mbuf *m, int eth_type, 467 int offset, bool allow_ecn, struct virtio_net_hdr *hdr) 468 { 469 static struct timeval lastecn; 470 static int curecn; 471 struct tcphdr *tcp, tcphdr; 472 473 if (__predict_false(m->m_len < offset + sizeof(struct tcphdr))) { 474 m_copydata(m, offset, sizeof(struct tcphdr), (caddr_t) &tcphdr); 475 tcp = &tcphdr; 476 } else 477 tcp = (struct tcphdr *)(m->m_data + offset); 478 479 hdr->hdr_len = offset + (tcp->th_off << 2); 480 hdr->gso_size = m->m_pkthdr.tso_segsz; 481 hdr->gso_type = eth_type == ETHERTYPE_IP ? VIRTIO_NET_HDR_GSO_TCPV4 : 482 VIRTIO_NET_HDR_GSO_TCPV6; 483 484 if (tcp->th_flags & TH_CWR) { 485 /* 486 * Drop if VIRTIO_NET_F_HOST_ECN was not negotiated. In FreeBSD, 487 * ECN support is not on a per-interface basis, but globally via 488 * the net.inet.tcp.ecn.enable sysctl knob. The default is off. 489 */ 490 if (!allow_ecn) { 491 if (ppsratecheck(&lastecn, &curecn, 1)) 492 if_printf(ifp, 493 "TSO with ECN not negotiated with host\n"); 494 return (ENOTSUP); 495 } 496 hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 497 } 498 499 /* Here we should increment tx_tso counter. */ 500 501 return (0); 502 } 503 504 static inline struct mbuf * 505 virtio_net_tx_offload(if_t ifp, struct mbuf *m, bool allow_ecn, 506 struct virtio_net_hdr *hdr) 507 { 508 int flags, etype, csum_start, proto, error; 509 510 flags = m->m_pkthdr.csum_flags; 511 512 error = virtio_net_tx_offload_ctx(m, &etype, &proto, &csum_start); 513 if (error) 514 goto drop; 515 516 if ((etype == ETHERTYPE_IP && (flags & (CSUM_TCP | CSUM_UDP))) || 517 (etype == ETHERTYPE_IPV6 && 518 (flags & (CSUM_TCP_IPV6 | CSUM_UDP_IPV6)))) { 519 /* 520 * We could compare the IP protocol vs the CSUM_ flag too, 521 * but that really should not be necessary. 522 */ 523 hdr->flags |= VIRTIO_NET_HDR_F_NEEDS_CSUM; 524 hdr->csum_start = csum_start; 525 hdr->csum_offset = m->m_pkthdr.csum_data; 526 /* Here we should increment the tx_csum counter. */ 527 } 528 529 if (flags & CSUM_TSO) { 530 if (__predict_false(proto != IPPROTO_TCP)) { 531 /* Likely failed to correctly parse the mbuf. 532 * Here we should increment the tx_tso_not_tcp 533 * counter. */ 534 goto drop; 535 } 536 537 KASSERT(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM, 538 ("%s: mbuf %p TSO without checksum offload %#x", 539 __func__, m, flags)); 540 541 error = virtio_net_tx_offload_tso(ifp, m, etype, csum_start, 542 allow_ecn, hdr); 543 if (error) 544 goto drop; 545 } 546 547 return (m); 548 549 drop: 550 m_freem(m); 551 return (NULL); 552 } 553 554 #endif /* _VIRTIO_NET_H */ 555