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 received 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
virtio_net_rx_csum_by_offset(struct mbuf * m,uint16_t eth_type,int ip_start,struct virtio_net_hdr * hdr)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
virtio_net_rx_csum_by_parse(struct mbuf * m,uint16_t eth_type,int ip_start,struct virtio_net_hdr * hdr)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
virtio_net_rx_csum(struct mbuf * m,struct virtio_net_hdr * hdr)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
virtio_net_tx_offload_ctx(struct mbuf * m,int * etype,int * proto,int * start)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
virtio_net_tx_offload_tso(if_t ifp,struct mbuf * m,int eth_type,int offset,bool allow_ecn,struct virtio_net_hdr * hdr)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 *
virtio_net_tx_offload(if_t ifp,struct mbuf * m,bool allow_ecn,struct virtio_net_hdr * hdr)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