qemu/hw/net/net_tx_pkt.c
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   1/*
   2 * QEMU TX packets abstractions
   3 *
   4 * Copyright (c) 2012 Ravello Systems LTD (http://ravellosystems.com)
   5 *
   6 * Developed by Daynix Computing LTD (http://www.daynix.com)
   7 *
   8 * Authors:
   9 * Dmitry Fleytman <dmitry@daynix.com>
  10 * Tamir Shomer <tamirs@daynix.com>
  11 * Yan Vugenfirer <yan@daynix.com>
  12 *
  13 * This work is licensed under the terms of the GNU GPL, version 2 or later.
  14 * See the COPYING file in the top-level directory.
  15 *
  16 */
  17
  18#include "qemu/osdep.h"
  19#include "net_tx_pkt.h"
  20#include "net/eth.h"
  21#include "net/checksum.h"
  22#include "net/tap.h"
  23#include "net/net.h"
  24#include "hw/pci/pci.h"
  25
  26enum {
  27    NET_TX_PKT_VHDR_FRAG = 0,
  28    NET_TX_PKT_L2HDR_FRAG,
  29    NET_TX_PKT_L3HDR_FRAG,
  30    NET_TX_PKT_PL_START_FRAG
  31};
  32
  33/* TX packet private context */
  34struct NetTxPkt {
  35    PCIDevice *pci_dev;
  36
  37    struct virtio_net_hdr virt_hdr;
  38    bool has_virt_hdr;
  39
  40    struct iovec *raw;
  41    uint32_t raw_frags;
  42    uint32_t max_raw_frags;
  43
  44    struct iovec *vec;
  45
  46    uint8_t l2_hdr[ETH_MAX_L2_HDR_LEN];
  47    uint8_t l3_hdr[ETH_MAX_IP_DGRAM_LEN];
  48
  49    uint32_t payload_len;
  50
  51    uint32_t payload_frags;
  52    uint32_t max_payload_frags;
  53
  54    uint16_t hdr_len;
  55    eth_pkt_types_e packet_type;
  56    uint8_t l4proto;
  57
  58    bool is_loopback;
  59};
  60
  61void net_tx_pkt_init(struct NetTxPkt **pkt, PCIDevice *pci_dev,
  62    uint32_t max_frags, bool has_virt_hdr)
  63{
  64    struct NetTxPkt *p = g_malloc0(sizeof *p);
  65
  66    p->pci_dev = pci_dev;
  67
  68    p->vec = g_new(struct iovec, max_frags + NET_TX_PKT_PL_START_FRAG);
  69
  70    p->raw = g_new(struct iovec, max_frags);
  71
  72    p->max_payload_frags = max_frags;
  73    p->max_raw_frags = max_frags;
  74    p->has_virt_hdr = has_virt_hdr;
  75    p->vec[NET_TX_PKT_VHDR_FRAG].iov_base = &p->virt_hdr;
  76    p->vec[NET_TX_PKT_VHDR_FRAG].iov_len =
  77        p->has_virt_hdr ? sizeof p->virt_hdr : 0;
  78    p->vec[NET_TX_PKT_L2HDR_FRAG].iov_base = &p->l2_hdr;
  79    p->vec[NET_TX_PKT_L3HDR_FRAG].iov_base = &p->l3_hdr;
  80
  81    *pkt = p;
  82}
  83
  84void net_tx_pkt_uninit(struct NetTxPkt *pkt)
  85{
  86    if (pkt) {
  87        g_free(pkt->vec);
  88        g_free(pkt->raw);
  89        g_free(pkt);
  90    }
  91}
  92
  93void net_tx_pkt_update_ip_hdr_checksum(struct NetTxPkt *pkt)
  94{
  95    uint16_t csum;
  96    assert(pkt);
  97    struct ip_header *ip_hdr;
  98    ip_hdr = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
  99
 100    ip_hdr->ip_len = cpu_to_be16(pkt->payload_len +
 101        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len);
 102
 103    ip_hdr->ip_sum = 0;
 104    csum = net_raw_checksum((uint8_t *)ip_hdr,
 105        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len);
 106    ip_hdr->ip_sum = cpu_to_be16(csum);
 107}
 108
 109void net_tx_pkt_update_ip_checksums(struct NetTxPkt *pkt)
 110{
 111    uint16_t csum;
 112    uint32_t cntr, cso;
 113    assert(pkt);
 114    uint8_t gso_type = pkt->virt_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN;
 115    void *ip_hdr = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
 116
 117    if (pkt->payload_len + pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len >
 118        ETH_MAX_IP_DGRAM_LEN) {
 119        return;
 120    }
 121
 122    if (gso_type == VIRTIO_NET_HDR_GSO_TCPV4 ||
 123        gso_type == VIRTIO_NET_HDR_GSO_UDP) {
 124        /* Calculate IP header checksum */
 125        net_tx_pkt_update_ip_hdr_checksum(pkt);
 126
 127        /* Calculate IP pseudo header checksum */
 128        cntr = eth_calc_ip4_pseudo_hdr_csum(ip_hdr, pkt->payload_len, &cso);
 129        csum = cpu_to_be16(~net_checksum_finish(cntr));
 130    } else if (gso_type == VIRTIO_NET_HDR_GSO_TCPV6) {
 131        /* Calculate IP pseudo header checksum */
 132        cntr = eth_calc_ip6_pseudo_hdr_csum(ip_hdr, pkt->payload_len,
 133                                            IP_PROTO_TCP, &cso);
 134        csum = cpu_to_be16(~net_checksum_finish(cntr));
 135    } else {
 136        return;
 137    }
 138
 139    iov_from_buf(&pkt->vec[NET_TX_PKT_PL_START_FRAG], pkt->payload_frags,
 140                 pkt->virt_hdr.csum_offset, &csum, sizeof(csum));
 141}
 142
 143static void net_tx_pkt_calculate_hdr_len(struct NetTxPkt *pkt)
 144{
 145    pkt->hdr_len = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len +
 146        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len;
 147}
 148
 149static bool net_tx_pkt_parse_headers(struct NetTxPkt *pkt)
 150{
 151    struct iovec *l2_hdr, *l3_hdr;
 152    size_t bytes_read;
 153    size_t full_ip6hdr_len;
 154    uint16_t l3_proto;
 155
 156    assert(pkt);
 157
 158    l2_hdr = &pkt->vec[NET_TX_PKT_L2HDR_FRAG];
 159    l3_hdr = &pkt->vec[NET_TX_PKT_L3HDR_FRAG];
 160
 161    bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, 0, l2_hdr->iov_base,
 162                            ETH_MAX_L2_HDR_LEN);
 163    if (bytes_read < sizeof(struct eth_header)) {
 164        l2_hdr->iov_len = 0;
 165        return false;
 166    }
 167
 168    l2_hdr->iov_len = sizeof(struct eth_header);
 169    switch (be16_to_cpu(PKT_GET_ETH_HDR(l2_hdr->iov_base)->h_proto)) {
 170    case ETH_P_VLAN:
 171        l2_hdr->iov_len += sizeof(struct vlan_header);
 172        break;
 173    case ETH_P_DVLAN:
 174        l2_hdr->iov_len += 2 * sizeof(struct vlan_header);
 175        break;
 176    }
 177
 178    if (bytes_read < l2_hdr->iov_len) {
 179        l2_hdr->iov_len = 0;
 180        l3_hdr->iov_len = 0;
 181        pkt->packet_type = ETH_PKT_UCAST;
 182        return false;
 183    } else {
 184        l2_hdr->iov_len = ETH_MAX_L2_HDR_LEN;
 185        l2_hdr->iov_len = eth_get_l2_hdr_length(l2_hdr->iov_base);
 186        pkt->packet_type = get_eth_packet_type(l2_hdr->iov_base);
 187    }
 188
 189    l3_proto = eth_get_l3_proto(l2_hdr, 1, l2_hdr->iov_len);
 190
 191    switch (l3_proto) {
 192    case ETH_P_IP:
 193        bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,
 194                                l3_hdr->iov_base, sizeof(struct ip_header));
 195
 196        if (bytes_read < sizeof(struct ip_header)) {
 197            l3_hdr->iov_len = 0;
 198            return false;
 199        }
 200
 201        l3_hdr->iov_len = IP_HDR_GET_LEN(l3_hdr->iov_base);
 202
 203        if (l3_hdr->iov_len < sizeof(struct ip_header)) {
 204            l3_hdr->iov_len = 0;
 205            return false;
 206        }
 207
 208        pkt->l4proto = ((struct ip_header *) l3_hdr->iov_base)->ip_p;
 209
 210        if (IP_HDR_GET_LEN(l3_hdr->iov_base) != sizeof(struct ip_header)) {
 211            /* copy optional IPv4 header data if any*/
 212            bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags,
 213                                    l2_hdr->iov_len + sizeof(struct ip_header),
 214                                    l3_hdr->iov_base + sizeof(struct ip_header),
 215                                    l3_hdr->iov_len - sizeof(struct ip_header));
 216            if (bytes_read < l3_hdr->iov_len - sizeof(struct ip_header)) {
 217                l3_hdr->iov_len = 0;
 218                return false;
 219            }
 220        }
 221
 222        break;
 223
 224    case ETH_P_IPV6:
 225    {
 226        eth_ip6_hdr_info hdrinfo;
 227
 228        if (!eth_parse_ipv6_hdr(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,
 229                                &hdrinfo)) {
 230            l3_hdr->iov_len = 0;
 231            return false;
 232        }
 233
 234        pkt->l4proto = hdrinfo.l4proto;
 235        full_ip6hdr_len = hdrinfo.full_hdr_len;
 236
 237        if (full_ip6hdr_len > ETH_MAX_IP_DGRAM_LEN) {
 238            l3_hdr->iov_len = 0;
 239            return false;
 240        }
 241
 242        bytes_read = iov_to_buf(pkt->raw, pkt->raw_frags, l2_hdr->iov_len,
 243                                l3_hdr->iov_base, full_ip6hdr_len);
 244
 245        if (bytes_read < full_ip6hdr_len) {
 246            l3_hdr->iov_len = 0;
 247            return false;
 248        } else {
 249            l3_hdr->iov_len = full_ip6hdr_len;
 250        }
 251        break;
 252    }
 253    default:
 254        l3_hdr->iov_len = 0;
 255        break;
 256    }
 257
 258    net_tx_pkt_calculate_hdr_len(pkt);
 259    return true;
 260}
 261
 262static void net_tx_pkt_rebuild_payload(struct NetTxPkt *pkt)
 263{
 264    pkt->payload_len = iov_size(pkt->raw, pkt->raw_frags) - pkt->hdr_len;
 265    pkt->payload_frags = iov_copy(&pkt->vec[NET_TX_PKT_PL_START_FRAG],
 266                                pkt->max_payload_frags,
 267                                pkt->raw, pkt->raw_frags,
 268                                pkt->hdr_len, pkt->payload_len);
 269}
 270
 271bool net_tx_pkt_parse(struct NetTxPkt *pkt)
 272{
 273    if (net_tx_pkt_parse_headers(pkt)) {
 274        net_tx_pkt_rebuild_payload(pkt);
 275        return true;
 276    } else {
 277        return false;
 278    }
 279}
 280
 281struct virtio_net_hdr *net_tx_pkt_get_vhdr(struct NetTxPkt *pkt)
 282{
 283    assert(pkt);
 284    return &pkt->virt_hdr;
 285}
 286
 287static uint8_t net_tx_pkt_get_gso_type(struct NetTxPkt *pkt,
 288                                          bool tso_enable)
 289{
 290    uint8_t rc = VIRTIO_NET_HDR_GSO_NONE;
 291    uint16_t l3_proto;
 292
 293    l3_proto = eth_get_l3_proto(&pkt->vec[NET_TX_PKT_L2HDR_FRAG], 1,
 294        pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len);
 295
 296    if (!tso_enable) {
 297        goto func_exit;
 298    }
 299
 300    rc = eth_get_gso_type(l3_proto, pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base,
 301                          pkt->l4proto);
 302
 303func_exit:
 304    return rc;
 305}
 306
 307void net_tx_pkt_build_vheader(struct NetTxPkt *pkt, bool tso_enable,
 308    bool csum_enable, uint32_t gso_size)
 309{
 310    struct tcp_hdr l4hdr;
 311    assert(pkt);
 312
 313    /* csum has to be enabled if tso is. */
 314    assert(csum_enable || !tso_enable);
 315
 316    pkt->virt_hdr.gso_type = net_tx_pkt_get_gso_type(pkt, tso_enable);
 317
 318    switch (pkt->virt_hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 319    case VIRTIO_NET_HDR_GSO_NONE:
 320        pkt->virt_hdr.hdr_len = 0;
 321        pkt->virt_hdr.gso_size = 0;
 322        break;
 323
 324    case VIRTIO_NET_HDR_GSO_UDP:
 325        pkt->virt_hdr.gso_size = gso_size;
 326        pkt->virt_hdr.hdr_len = pkt->hdr_len + sizeof(struct udp_header);
 327        break;
 328
 329    case VIRTIO_NET_HDR_GSO_TCPV4:
 330    case VIRTIO_NET_HDR_GSO_TCPV6:
 331        iov_to_buf(&pkt->vec[NET_TX_PKT_PL_START_FRAG], pkt->payload_frags,
 332                   0, &l4hdr, sizeof(l4hdr));
 333        pkt->virt_hdr.hdr_len = pkt->hdr_len + l4hdr.th_off * sizeof(uint32_t);
 334        pkt->virt_hdr.gso_size = gso_size;
 335        break;
 336
 337    default:
 338        g_assert_not_reached();
 339    }
 340
 341    if (csum_enable) {
 342        switch (pkt->l4proto) {
 343        case IP_PROTO_TCP:
 344            pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 345            pkt->virt_hdr.csum_start = pkt->hdr_len;
 346            pkt->virt_hdr.csum_offset = offsetof(struct tcp_hdr, th_sum);
 347            break;
 348        case IP_PROTO_UDP:
 349            pkt->virt_hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 350            pkt->virt_hdr.csum_start = pkt->hdr_len;
 351            pkt->virt_hdr.csum_offset = offsetof(struct udp_hdr, uh_sum);
 352            break;
 353        default:
 354            break;
 355        }
 356    }
 357}
 358
 359void net_tx_pkt_setup_vlan_header_ex(struct NetTxPkt *pkt,
 360    uint16_t vlan, uint16_t vlan_ethtype)
 361{
 362    bool is_new;
 363    assert(pkt);
 364
 365    eth_setup_vlan_headers_ex(pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_base,
 366        vlan, vlan_ethtype, &is_new);
 367
 368    /* update l2hdrlen */
 369    if (is_new) {
 370        pkt->hdr_len += sizeof(struct vlan_header);
 371        pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len +=
 372            sizeof(struct vlan_header);
 373    }
 374}
 375
 376bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, hwaddr pa,
 377    size_t len)
 378{
 379    hwaddr mapped_len = 0;
 380    struct iovec *ventry;
 381    assert(pkt);
 382    assert(pkt->max_raw_frags > pkt->raw_frags);
 383
 384    if (!len) {
 385        return true;
 386     }
 387
 388    ventry = &pkt->raw[pkt->raw_frags];
 389    mapped_len = len;
 390
 391    ventry->iov_base = pci_dma_map(pkt->pci_dev, pa,
 392                                   &mapped_len, DMA_DIRECTION_TO_DEVICE);
 393
 394    if ((ventry->iov_base != NULL) && (len == mapped_len)) {
 395        ventry->iov_len = mapped_len;
 396        pkt->raw_frags++;
 397        return true;
 398    } else {
 399        return false;
 400    }
 401}
 402
 403bool net_tx_pkt_has_fragments(struct NetTxPkt *pkt)
 404{
 405    return pkt->raw_frags > 0;
 406}
 407
 408eth_pkt_types_e net_tx_pkt_get_packet_type(struct NetTxPkt *pkt)
 409{
 410    assert(pkt);
 411
 412    return pkt->packet_type;
 413}
 414
 415size_t net_tx_pkt_get_total_len(struct NetTxPkt *pkt)
 416{
 417    assert(pkt);
 418
 419    return pkt->hdr_len + pkt->payload_len;
 420}
 421
 422void net_tx_pkt_dump(struct NetTxPkt *pkt)
 423{
 424#ifdef NET_TX_PKT_DEBUG
 425    assert(pkt);
 426
 427    printf("TX PKT: hdr_len: %d, pkt_type: 0x%X, l2hdr_len: %lu, "
 428        "l3hdr_len: %lu, payload_len: %u\n", pkt->hdr_len, pkt->packet_type,
 429        pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len,
 430        pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len, pkt->payload_len);
 431#endif
 432}
 433
 434void net_tx_pkt_reset(struct NetTxPkt *pkt)
 435{
 436    int i;
 437
 438    /* no assert, as reset can be called before tx_pkt_init */
 439    if (!pkt) {
 440        return;
 441    }
 442
 443    memset(&pkt->virt_hdr, 0, sizeof(pkt->virt_hdr));
 444
 445    assert(pkt->vec);
 446
 447    pkt->payload_len = 0;
 448    pkt->payload_frags = 0;
 449
 450    assert(pkt->raw);
 451    for (i = 0; i < pkt->raw_frags; i++) {
 452        assert(pkt->raw[i].iov_base);
 453        pci_dma_unmap(pkt->pci_dev, pkt->raw[i].iov_base, pkt->raw[i].iov_len,
 454                      DMA_DIRECTION_TO_DEVICE, 0);
 455    }
 456    pkt->raw_frags = 0;
 457
 458    pkt->hdr_len = 0;
 459    pkt->l4proto = 0;
 460}
 461
 462static void net_tx_pkt_do_sw_csum(struct NetTxPkt *pkt)
 463{
 464    struct iovec *iov = &pkt->vec[NET_TX_PKT_L2HDR_FRAG];
 465    uint32_t csum_cntr;
 466    uint16_t csum = 0;
 467    uint32_t cso;
 468    /* num of iovec without vhdr */
 469    uint32_t iov_len = pkt->payload_frags + NET_TX_PKT_PL_START_FRAG - 1;
 470    uint16_t csl;
 471    struct ip_header *iphdr;
 472    size_t csum_offset = pkt->virt_hdr.csum_start + pkt->virt_hdr.csum_offset;
 473
 474    /* Put zero to checksum field */
 475    iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum);
 476
 477    /* Calculate L4 TCP/UDP checksum */
 478    csl = pkt->payload_len;
 479
 480    /* add pseudo header to csum */
 481    iphdr = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
 482    csum_cntr = eth_calc_ip4_pseudo_hdr_csum(iphdr, csl, &cso);
 483
 484    /* data checksum */
 485    csum_cntr +=
 486        net_checksum_add_iov(iov, iov_len, pkt->virt_hdr.csum_start, csl, cso);
 487
 488    /* Put the checksum obtained into the packet */
 489    csum = cpu_to_be16(net_checksum_finish_nozero(csum_cntr));
 490    iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum);
 491}
 492
 493enum {
 494    NET_TX_PKT_FRAGMENT_L2_HDR_POS = 0,
 495    NET_TX_PKT_FRAGMENT_L3_HDR_POS,
 496    NET_TX_PKT_FRAGMENT_HEADER_NUM
 497};
 498
 499#define NET_MAX_FRAG_SG_LIST (64)
 500
 501static size_t net_tx_pkt_fetch_fragment(struct NetTxPkt *pkt,
 502    int *src_idx, size_t *src_offset, struct iovec *dst, int *dst_idx)
 503{
 504    size_t fetched = 0;
 505    struct iovec *src = pkt->vec;
 506
 507    *dst_idx = NET_TX_PKT_FRAGMENT_HEADER_NUM;
 508
 509    while (fetched < IP_FRAG_ALIGN_SIZE(pkt->virt_hdr.gso_size)) {
 510
 511        /* no more place in fragment iov */
 512        if (*dst_idx == NET_MAX_FRAG_SG_LIST) {
 513            break;
 514        }
 515
 516        /* no more data in iovec */
 517        if (*src_idx == (pkt->payload_frags + NET_TX_PKT_PL_START_FRAG)) {
 518            break;
 519        }
 520
 521
 522        dst[*dst_idx].iov_base = src[*src_idx].iov_base + *src_offset;
 523        dst[*dst_idx].iov_len = MIN(src[*src_idx].iov_len - *src_offset,
 524            IP_FRAG_ALIGN_SIZE(pkt->virt_hdr.gso_size) - fetched);
 525
 526        *src_offset += dst[*dst_idx].iov_len;
 527        fetched += dst[*dst_idx].iov_len;
 528
 529        if (*src_offset == src[*src_idx].iov_len) {
 530            *src_offset = 0;
 531            (*src_idx)++;
 532        }
 533
 534        (*dst_idx)++;
 535    }
 536
 537    return fetched;
 538}
 539
 540static inline void net_tx_pkt_sendv(struct NetTxPkt *pkt,
 541    NetClientState *nc, const struct iovec *iov, int iov_cnt)
 542{
 543    if (pkt->is_loopback) {
 544        nc->info->receive_iov(nc, iov, iov_cnt);
 545    } else {
 546        qemu_sendv_packet(nc, iov, iov_cnt);
 547    }
 548}
 549
 550static bool net_tx_pkt_do_sw_fragmentation(struct NetTxPkt *pkt,
 551    NetClientState *nc)
 552{
 553    struct iovec fragment[NET_MAX_FRAG_SG_LIST];
 554    size_t fragment_len = 0;
 555    bool more_frags = false;
 556
 557    /* some pointers for shorter code */
 558    void *l2_iov_base, *l3_iov_base;
 559    size_t l2_iov_len, l3_iov_len;
 560    int src_idx =  NET_TX_PKT_PL_START_FRAG, dst_idx;
 561    size_t src_offset = 0;
 562    size_t fragment_offset = 0;
 563
 564    l2_iov_base = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_base;
 565    l2_iov_len = pkt->vec[NET_TX_PKT_L2HDR_FRAG].iov_len;
 566    l3_iov_base = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
 567    l3_iov_len = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len;
 568
 569    /* Copy headers */
 570    fragment[NET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_base = l2_iov_base;
 571    fragment[NET_TX_PKT_FRAGMENT_L2_HDR_POS].iov_len = l2_iov_len;
 572    fragment[NET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_base = l3_iov_base;
 573    fragment[NET_TX_PKT_FRAGMENT_L3_HDR_POS].iov_len = l3_iov_len;
 574
 575
 576    /* Put as much data as possible and send */
 577    do {
 578        fragment_len = net_tx_pkt_fetch_fragment(pkt, &src_idx, &src_offset,
 579            fragment, &dst_idx);
 580
 581        more_frags = (fragment_offset + fragment_len < pkt->payload_len);
 582
 583        eth_setup_ip4_fragmentation(l2_iov_base, l2_iov_len, l3_iov_base,
 584            l3_iov_len, fragment_len, fragment_offset, more_frags);
 585
 586        eth_fix_ip4_checksum(l3_iov_base, l3_iov_len);
 587
 588        net_tx_pkt_sendv(pkt, nc, fragment, dst_idx);
 589
 590        fragment_offset += fragment_len;
 591
 592    } while (fragment_len && more_frags);
 593
 594    return true;
 595}
 596
 597bool net_tx_pkt_send(struct NetTxPkt *pkt, NetClientState *nc)
 598{
 599    assert(pkt);
 600
 601    if (!pkt->has_virt_hdr &&
 602        pkt->virt_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 603        net_tx_pkt_do_sw_csum(pkt);
 604    }
 605
 606    /*
 607     * Since underlying infrastructure does not support IP datagrams longer
 608     * than 64K we should drop such packets and don't even try to send
 609     */
 610    if (VIRTIO_NET_HDR_GSO_NONE != pkt->virt_hdr.gso_type) {
 611        if (pkt->payload_len >
 612            ETH_MAX_IP_DGRAM_LEN -
 613            pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len) {
 614            return false;
 615        }
 616    }
 617
 618    if (pkt->has_virt_hdr ||
 619        pkt->virt_hdr.gso_type == VIRTIO_NET_HDR_GSO_NONE) {
 620        net_tx_pkt_sendv(pkt, nc, pkt->vec,
 621            pkt->payload_frags + NET_TX_PKT_PL_START_FRAG);
 622        return true;
 623    }
 624
 625    return net_tx_pkt_do_sw_fragmentation(pkt, nc);
 626}
 627
 628bool net_tx_pkt_send_loopback(struct NetTxPkt *pkt, NetClientState *nc)
 629{
 630    bool res;
 631
 632    pkt->is_loopback = true;
 633    res = net_tx_pkt_send(pkt, nc);
 634    pkt->is_loopback = false;
 635
 636    return res;
 637}
 638