summaryrefslogtreecommitdiff
path: root/hw/net/net_rx_pkt.c
blob: 1e1c504e425f34ce755f9eedeb0f760210f9bbc7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
/*
 * QEMU RX packets abstractions
 *
 * Copyright (c) 2012 Ravello Systems LTD (http://ravellosystems.com)
 *
 * Developed by Daynix Computing LTD (http://www.daynix.com)
 *
 * Authors:
 * Dmitry Fleytman <dmitry@daynix.com>
 * Tamir Shomer <tamirs@daynix.com>
 * Yan Vugenfirer <yan@daynix.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "qemu/osdep.h"
#include "trace.h"
#include "net_rx_pkt.h"
#include "net/checksum.h"
#include "net/tap.h"

struct NetRxPkt {
    struct virtio_net_hdr virt_hdr;
    uint8_t ehdr_buf[sizeof(struct eth_header) + sizeof(struct vlan_header)];
    struct iovec *vec;
    uint16_t vec_len_total;
    uint16_t vec_len;
    uint32_t tot_len;
    uint16_t tci;
    size_t ehdr_buf_len;
    bool has_virt_hdr;
    eth_pkt_types_e packet_type;

    /* Analysis results */
    bool isip4;
    bool isip6;
    bool isudp;
    bool istcp;

    size_t l3hdr_off;
    size_t l4hdr_off;
    size_t l5hdr_off;

    eth_ip6_hdr_info ip6hdr_info;
    eth_ip4_hdr_info ip4hdr_info;
    eth_l4_hdr_info  l4hdr_info;
};

void net_rx_pkt_init(struct NetRxPkt **pkt, bool has_virt_hdr)
{
    struct NetRxPkt *p = g_malloc0(sizeof *p);
    p->has_virt_hdr = has_virt_hdr;
    p->vec = NULL;
    p->vec_len_total = 0;
    *pkt = p;
}

void net_rx_pkt_uninit(struct NetRxPkt *pkt)
{
    if (pkt->vec_len_total != 0) {
        g_free(pkt->vec);
    }

    g_free(pkt);
}

struct virtio_net_hdr *net_rx_pkt_get_vhdr(struct NetRxPkt *pkt)
{
    assert(pkt);
    return &pkt->virt_hdr;
}

static inline void
net_rx_pkt_iovec_realloc(struct NetRxPkt *pkt,
                            int new_iov_len)
{
    if (pkt->vec_len_total < new_iov_len) {
        g_free(pkt->vec);
        pkt->vec = g_malloc(sizeof(*pkt->vec) * new_iov_len);
        pkt->vec_len_total = new_iov_len;
    }
}

static void
net_rx_pkt_pull_data(struct NetRxPkt *pkt,
                        const struct iovec *iov, int iovcnt,
                        size_t ploff)
{
    uint32_t pllen = iov_size(iov, iovcnt) - ploff;

    if (pkt->ehdr_buf_len) {
        net_rx_pkt_iovec_realloc(pkt, iovcnt + 1);

        pkt->vec[0].iov_base = pkt->ehdr_buf;
        pkt->vec[0].iov_len = pkt->ehdr_buf_len;

        pkt->tot_len = pllen + pkt->ehdr_buf_len;
        pkt->vec_len = iov_copy(pkt->vec + 1, pkt->vec_len_total - 1,
                                iov, iovcnt, ploff, pllen) + 1;
    } else {
        net_rx_pkt_iovec_realloc(pkt, iovcnt);

        pkt->tot_len = pllen;
        pkt->vec_len = iov_copy(pkt->vec, pkt->vec_len_total,
                                iov, iovcnt, ploff, pkt->tot_len);
    }

    eth_get_protocols(pkt->vec, pkt->vec_len, &pkt->isip4, &pkt->isip6,
                      &pkt->isudp, &pkt->istcp,
                      &pkt->l3hdr_off, &pkt->l4hdr_off, &pkt->l5hdr_off,
                      &pkt->ip6hdr_info, &pkt->ip4hdr_info, &pkt->l4hdr_info);

    trace_net_rx_pkt_parsed(pkt->isip4, pkt->isip6, pkt->isudp, pkt->istcp,
                            pkt->l3hdr_off, pkt->l4hdr_off, pkt->l5hdr_off);
}

void net_rx_pkt_attach_iovec(struct NetRxPkt *pkt,
                                const struct iovec *iov, int iovcnt,
                                size_t iovoff, bool strip_vlan)
{
    uint16_t tci = 0;
    uint16_t ploff = iovoff;
    assert(pkt);

    if (strip_vlan) {
        pkt->ehdr_buf_len = eth_strip_vlan(iov, iovcnt, iovoff, pkt->ehdr_buf,
                                           &ploff, &tci);
    } else {
        pkt->ehdr_buf_len = 0;
    }

    pkt->tci = tci;

    net_rx_pkt_pull_data(pkt, iov, iovcnt, ploff);
}

void net_rx_pkt_attach_iovec_ex(struct NetRxPkt *pkt,
                                const struct iovec *iov, int iovcnt,
                                size_t iovoff, bool strip_vlan,
                                uint16_t vet)
{
    uint16_t tci = 0;
    uint16_t ploff = iovoff;
    assert(pkt);

    if (strip_vlan) {
        pkt->ehdr_buf_len = eth_strip_vlan_ex(iov, iovcnt, iovoff, vet,
                                              pkt->ehdr_buf,
                                              &ploff, &tci);
    } else {
        pkt->ehdr_buf_len = 0;
    }

    pkt->tci = tci;

    net_rx_pkt_pull_data(pkt, iov, iovcnt, ploff);
}

void net_rx_pkt_dump(struct NetRxPkt *pkt)
{
#ifdef NET_RX_PKT_DEBUG
    assert(pkt);

    printf("RX PKT: tot_len: %d, ehdr_buf_len: %lu, vlan_tag: %d\n",
              pkt->tot_len, pkt->ehdr_buf_len, pkt->tci);
#endif
}

void net_rx_pkt_set_packet_type(struct NetRxPkt *pkt,
    eth_pkt_types_e packet_type)
{
    assert(pkt);

    pkt->packet_type = packet_type;

}

eth_pkt_types_e net_rx_pkt_get_packet_type(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->packet_type;
}

size_t net_rx_pkt_get_total_len(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->tot_len;
}

void net_rx_pkt_set_protocols(struct NetRxPkt *pkt, const void *data,
                              size_t len)
{
    const struct iovec iov = {
        .iov_base = (void *)data,
        .iov_len = len
    };

    assert(pkt);

    eth_get_protocols(&iov, 1, &pkt->isip4, &pkt->isip6,
                      &pkt->isudp, &pkt->istcp,
                      &pkt->l3hdr_off, &pkt->l4hdr_off, &pkt->l5hdr_off,
                      &pkt->ip6hdr_info, &pkt->ip4hdr_info, &pkt->l4hdr_info);
}

void net_rx_pkt_get_protocols(struct NetRxPkt *pkt,
                              bool *isip4, bool *isip6,
                              bool *isudp, bool *istcp)
{
    assert(pkt);

    *isip4 = pkt->isip4;
    *isip6 = pkt->isip6;
    *isudp = pkt->isudp;
    *istcp = pkt->istcp;
}

size_t net_rx_pkt_get_l3_hdr_offset(struct NetRxPkt *pkt)
{
    assert(pkt);
    return pkt->l3hdr_off;
}

size_t net_rx_pkt_get_l4_hdr_offset(struct NetRxPkt *pkt)
{
    assert(pkt);
    return pkt->l4hdr_off;
}

size_t net_rx_pkt_get_l5_hdr_offset(struct NetRxPkt *pkt)
{
    assert(pkt);
    return pkt->l5hdr_off;
}

eth_ip6_hdr_info *net_rx_pkt_get_ip6_info(struct NetRxPkt *pkt)
{
    return &pkt->ip6hdr_info;
}

eth_ip4_hdr_info *net_rx_pkt_get_ip4_info(struct NetRxPkt *pkt)
{
    return &pkt->ip4hdr_info;
}

eth_l4_hdr_info *net_rx_pkt_get_l4_info(struct NetRxPkt *pkt)
{
    return &pkt->l4hdr_info;
}

static inline void
_net_rx_rss_add_chunk(uint8_t *rss_input, size_t *bytes_written,
                      void *ptr, size_t size)
{
    memcpy(&rss_input[*bytes_written], ptr, size);
    trace_net_rx_pkt_rss_add_chunk(ptr, size, *bytes_written);
    *bytes_written += size;
}

static inline void
_net_rx_rss_prepare_ip4(uint8_t *rss_input,
                        struct NetRxPkt *pkt,
                        size_t *bytes_written)
{
    struct ip_header *ip4_hdr = &pkt->ip4hdr_info.ip4_hdr;

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &ip4_hdr->ip_src, sizeof(uint32_t));

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &ip4_hdr->ip_dst, sizeof(uint32_t));
}

static inline void
_net_rx_rss_prepare_ip6(uint8_t *rss_input,
                        struct NetRxPkt *pkt,
                        bool ipv6ex, size_t *bytes_written)
{
    eth_ip6_hdr_info *ip6info = &pkt->ip6hdr_info;

    _net_rx_rss_add_chunk(rss_input, bytes_written,
           (ipv6ex && ip6info->rss_ex_src_valid) ? &ip6info->rss_ex_src
                                                 : &ip6info->ip6_hdr.ip6_src,
           sizeof(struct in6_address));

    _net_rx_rss_add_chunk(rss_input, bytes_written,
           (ipv6ex && ip6info->rss_ex_dst_valid) ? &ip6info->rss_ex_dst
                                                 : &ip6info->ip6_hdr.ip6_dst,
           sizeof(struct in6_address));
}

static inline void
_net_rx_rss_prepare_tcp(uint8_t *rss_input,
                        struct NetRxPkt *pkt,
                        size_t *bytes_written)
{
    struct tcp_header *tcphdr = &pkt->l4hdr_info.hdr.tcp;

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &tcphdr->th_sport, sizeof(uint16_t));

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &tcphdr->th_dport, sizeof(uint16_t));
}

static inline void
_net_rx_rss_prepare_udp(uint8_t *rss_input,
                        struct NetRxPkt *pkt,
                        size_t *bytes_written)
{
    struct udp_header *udphdr = &pkt->l4hdr_info.hdr.udp;

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &udphdr->uh_sport, sizeof(uint16_t));

    _net_rx_rss_add_chunk(rss_input, bytes_written,
                          &udphdr->uh_dport, sizeof(uint16_t));
}

uint32_t
net_rx_pkt_calc_rss_hash(struct NetRxPkt *pkt,
                         NetRxPktRssType type,
                         uint8_t *key)
{
    uint8_t rss_input[36];
    size_t rss_length = 0;
    uint32_t rss_hash = 0;
    net_toeplitz_key key_data;

    switch (type) {
    case NetPktRssIpV4:
        assert(pkt->isip4);
        trace_net_rx_pkt_rss_ip4();
        _net_rx_rss_prepare_ip4(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV4Tcp:
        assert(pkt->isip4);
        assert(pkt->istcp);
        trace_net_rx_pkt_rss_ip4_tcp();
        _net_rx_rss_prepare_ip4(&rss_input[0], pkt, &rss_length);
        _net_rx_rss_prepare_tcp(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV6Tcp:
        assert(pkt->isip6);
        assert(pkt->istcp);
        trace_net_rx_pkt_rss_ip6_tcp();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, false, &rss_length);
        _net_rx_rss_prepare_tcp(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV6:
        assert(pkt->isip6);
        trace_net_rx_pkt_rss_ip6();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, false, &rss_length);
        break;
    case NetPktRssIpV6Ex:
        assert(pkt->isip6);
        trace_net_rx_pkt_rss_ip6_ex();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, true, &rss_length);
        break;
    case NetPktRssIpV6TcpEx:
        assert(pkt->isip6);
        assert(pkt->istcp);
        trace_net_rx_pkt_rss_ip6_ex_tcp();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, true, &rss_length);
        _net_rx_rss_prepare_tcp(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV4Udp:
        assert(pkt->isip4);
        assert(pkt->isudp);
        trace_net_rx_pkt_rss_ip4_udp();
        _net_rx_rss_prepare_ip4(&rss_input[0], pkt, &rss_length);
        _net_rx_rss_prepare_udp(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV6Udp:
        assert(pkt->isip6);
        assert(pkt->isudp);
        trace_net_rx_pkt_rss_ip6_udp();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, false, &rss_length);
        _net_rx_rss_prepare_udp(&rss_input[0], pkt, &rss_length);
        break;
    case NetPktRssIpV6UdpEx:
        assert(pkt->isip6);
        assert(pkt->isudp);
        trace_net_rx_pkt_rss_ip6_ex_udp();
        _net_rx_rss_prepare_ip6(&rss_input[0], pkt, true, &rss_length);
        _net_rx_rss_prepare_udp(&rss_input[0], pkt, &rss_length);
        break;
    default:
        assert(false);
        break;
    }

    net_toeplitz_key_init(&key_data, key);
    net_toeplitz_add(&rss_hash, rss_input, rss_length, &key_data);

    trace_net_rx_pkt_rss_hash(rss_length, rss_hash);

    return rss_hash;
}

uint16_t net_rx_pkt_get_ip_id(struct NetRxPkt *pkt)
{
    assert(pkt);

    if (pkt->isip4) {
        return be16_to_cpu(pkt->ip4hdr_info.ip4_hdr.ip_id);
    }

    return 0;
}

bool net_rx_pkt_is_tcp_ack(struct NetRxPkt *pkt)
{
    assert(pkt);

    if (pkt->istcp) {
        return TCP_HEADER_FLAGS(&pkt->l4hdr_info.hdr.tcp) & TCP_FLAG_ACK;
    }

    return false;
}

bool net_rx_pkt_has_tcp_data(struct NetRxPkt *pkt)
{
    assert(pkt);

    if (pkt->istcp) {
        return pkt->l4hdr_info.has_tcp_data;
    }

    return false;
}

struct iovec *net_rx_pkt_get_iovec(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->vec;
}

uint16_t net_rx_pkt_get_iovec_len(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->vec_len;
}

void net_rx_pkt_set_vhdr(struct NetRxPkt *pkt,
                            struct virtio_net_hdr *vhdr)
{
    assert(pkt);

    memcpy(&pkt->virt_hdr, vhdr, sizeof pkt->virt_hdr);
}

void net_rx_pkt_set_vhdr_iovec(struct NetRxPkt *pkt,
    const struct iovec *iov, int iovcnt)
{
    assert(pkt);

    iov_to_buf(iov, iovcnt, 0, &pkt->virt_hdr, sizeof pkt->virt_hdr);
}

bool net_rx_pkt_is_vlan_stripped(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->ehdr_buf_len ? true : false;
}

bool net_rx_pkt_has_virt_hdr(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->has_virt_hdr;
}

uint16_t net_rx_pkt_get_vlan_tag(struct NetRxPkt *pkt)
{
    assert(pkt);

    return pkt->tci;
}

bool net_rx_pkt_validate_l3_csum(struct NetRxPkt *pkt, bool *csum_valid)
{
    uint32_t cntr;
    uint16_t csum;
    uint32_t csl;

    trace_net_rx_pkt_l3_csum_validate_entry();

    if (!pkt->isip4) {
        trace_net_rx_pkt_l3_csum_validate_not_ip4();
        return false;
    }

    csl = pkt->l4hdr_off - pkt->l3hdr_off;

    cntr = net_checksum_add_iov(pkt->vec, pkt->vec_len,
                                pkt->l3hdr_off,
                                csl, 0);

    csum = net_checksum_finish(cntr);

    *csum_valid = (csum == 0);

    trace_net_rx_pkt_l3_csum_validate_csum(pkt->l3hdr_off, csl,
                                           cntr, csum, *csum_valid);

    return true;
}

static uint16_t
_net_rx_pkt_calc_l4_csum(struct NetRxPkt *pkt)
{
    uint32_t cntr;
    uint16_t csum;
    uint16_t csl;
    uint32_t cso;

    trace_net_rx_pkt_l4_csum_calc_entry();

    if (pkt->isip4) {
        if (pkt->isudp) {
            csl = be16_to_cpu(pkt->l4hdr_info.hdr.udp.uh_ulen);
            trace_net_rx_pkt_l4_csum_calc_ip4_udp();
        } else {
            csl = be16_to_cpu(pkt->ip4hdr_info.ip4_hdr.ip_len) -
                  IP_HDR_GET_LEN(&pkt->ip4hdr_info.ip4_hdr);
            trace_net_rx_pkt_l4_csum_calc_ip4_tcp();
        }

        cntr = eth_calc_ip4_pseudo_hdr_csum(&pkt->ip4hdr_info.ip4_hdr,
                                            csl, &cso);
        trace_net_rx_pkt_l4_csum_calc_ph_csum(cntr, csl);
    } else {
        if (pkt->isudp) {
            csl = be16_to_cpu(pkt->l4hdr_info.hdr.udp.uh_ulen);
            trace_net_rx_pkt_l4_csum_calc_ip6_udp();
        } else {
            struct ip6_header *ip6hdr = &pkt->ip6hdr_info.ip6_hdr;
            size_t full_ip6hdr_len = pkt->l4hdr_off - pkt->l3hdr_off;
            size_t ip6opts_len = full_ip6hdr_len - sizeof(struct ip6_header);

            csl = be16_to_cpu(ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_plen) -
                  ip6opts_len;
            trace_net_rx_pkt_l4_csum_calc_ip6_tcp();
        }

        cntr = eth_calc_ip6_pseudo_hdr_csum(&pkt->ip6hdr_info.ip6_hdr, csl,
                                            pkt->ip6hdr_info.l4proto, &cso);
        trace_net_rx_pkt_l4_csum_calc_ph_csum(cntr, csl);
    }

    cntr += net_checksum_add_iov(pkt->vec, pkt->vec_len,
                                 pkt->l4hdr_off, csl, cso);

    csum = net_checksum_finish_nozero(cntr);

    trace_net_rx_pkt_l4_csum_calc_csum(pkt->l4hdr_off, csl, cntr, csum);

    return csum;
}

bool net_rx_pkt_validate_l4_csum(struct NetRxPkt *pkt, bool *csum_valid)
{
    uint16_t csum;

    trace_net_rx_pkt_l4_csum_validate_entry();

    if (!pkt->istcp && !pkt->isudp) {
        trace_net_rx_pkt_l4_csum_validate_not_xxp();
        return false;
    }

    if (pkt->isudp && (pkt->l4hdr_info.hdr.udp.uh_sum == 0)) {
        trace_net_rx_pkt_l4_csum_validate_udp_with_no_checksum();
        return false;
    }

    if (pkt->isip4 && pkt->ip4hdr_info.fragment) {
        trace_net_rx_pkt_l4_csum_validate_ip4_fragment();
        return false;
    }

    csum = _net_rx_pkt_calc_l4_csum(pkt);

    *csum_valid = ((csum == 0) || (csum == 0xFFFF));

    trace_net_rx_pkt_l4_csum_validate_csum(*csum_valid);

    return true;
}

bool net_rx_pkt_fix_l4_csum(struct NetRxPkt *pkt)
{
    uint16_t csum = 0;
    uint32_t l4_cso;

    trace_net_rx_pkt_l4_csum_fix_entry();

    if (pkt->istcp) {
        l4_cso = offsetof(struct tcp_header, th_sum);
        trace_net_rx_pkt_l4_csum_fix_tcp(l4_cso);
    } else if (pkt->isudp) {
        if (pkt->l4hdr_info.hdr.udp.uh_sum == 0) {
            trace_net_rx_pkt_l4_csum_fix_udp_with_no_checksum();
            return false;
        }
        l4_cso = offsetof(struct udp_header, uh_sum);
        trace_net_rx_pkt_l4_csum_fix_udp(l4_cso);
    } else {
        trace_net_rx_pkt_l4_csum_fix_not_xxp();
        return false;
    }

    if (pkt->isip4 && pkt->ip4hdr_info.fragment) {
            trace_net_rx_pkt_l4_csum_fix_ip4_fragment();
            return false;
    }

    /* Set zero to checksum word */
    iov_from_buf(pkt->vec, pkt->vec_len,
                 pkt->l4hdr_off + l4_cso,
                 &csum, sizeof(csum));

    /* Calculate L4 checksum */
    csum = cpu_to_be16(_net_rx_pkt_calc_l4_csum(pkt));

    /* Set calculated checksum to checksum word */
    iov_from_buf(pkt->vec, pkt->vec_len,
                 pkt->l4hdr_off + l4_cso,
                 &csum, sizeof(csum));

    trace_net_rx_pkt_l4_csum_fix_csum(pkt->l4hdr_off + l4_cso, csum);

    return true;
}