hw/net/net_tx_pkt.c

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