net/eth.c

   1 /*
   2  * QEMU network structures definitions and helper functions
   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 <[email protected]>
  10  * Tamir Shomer <[email protected]>
  11  * Yan Vugenfirer <[email protected]>
  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/eth.h"
  20 #include "net/checksum.h"
  21 #include "qemu-common.h"
  22 #include "net/tap.h"
  23
  24 void eth_setup_vlan_headers_ex(struct eth_header *ehdr, uint16_t vlan_tag,
  25     uint16_t vlan_ethtype, bool *is_new)
  26 {
  27     struct vlan_header *vhdr = PKT_GET_VLAN_HDR(ehdr);
  28
  29     switch (be16_to_cpu(ehdr->h_proto)) {
  30     case ETH_P_VLAN:
  31     case ETH_P_DVLAN:
  32         /* vlan hdr exists */
  33         *is_new = false;
  34         break;
  35
  36     default:
  37         /* No VLAN header, put a new one */
  38         vhdr->h_proto = ehdr->h_proto;
  39         ehdr->h_proto = cpu_to_be16(vlan_ethtype);
  40         *is_new = true;
  41         break;
  42     }
  43     vhdr->h_tci = cpu_to_be16(vlan_tag);
  44 }
  45
  46 uint8_t
  47 eth_get_gso_type(uint16_t l3_proto, uint8_t *l3_hdr, uint8_t l4proto)
  48 {
  49     uint8_t ecn_state = 0;
  50
  51     if (l3_proto == ETH_P_IP) {
  52         struct ip_header *iphdr = (struct ip_header *) l3_hdr;
  53
  54         if (IP_HEADER_VERSION(iphdr) == IP_HEADER_VERSION_4) {
  55             if (IPTOS_ECN(iphdr->ip_tos) == IPTOS_ECN_CE) {
  56                 ecn_state = VIRTIO_NET_HDR_GSO_ECN;
  57             }
  58             if (l4proto == IP_PROTO_TCP) {
  59                 return VIRTIO_NET_HDR_GSO_TCPV4 | ecn_state;
  60             } else if (l4proto == IP_PROTO_UDP) {
  61                 return VIRTIO_NET_HDR_GSO_UDP | ecn_state;
  62             }
  63         }
  64     } else if (l3_proto == ETH_P_IPV6) {
  65         struct ip6_header *ip6hdr = (struct ip6_header *) l3_hdr;
  66
  67         if (IP6_ECN(ip6hdr->ip6_ecn_acc) == IP6_ECN_CE) {
  68             ecn_state = VIRTIO_NET_HDR_GSO_ECN;
  69         }
  70
  71         if (l4proto == IP_PROTO_TCP) {
  72             return VIRTIO_NET_HDR_GSO_TCPV6 | ecn_state;
  73         }
  74     }
  75
  76     /* Unsupported offload */
  77     g_assert_not_reached();
  78
  79     return VIRTIO_NET_HDR_GSO_NONE | ecn_state;
  80 }
  81
  82 uint16_t
  83 eth_get_l3_proto(const struct iovec *l2hdr_iov, int iovcnt, size_t l2hdr_len)
  84 {
  85     uint16_t proto;
  86     size_t copied;
  87     size_t size = iov_size(l2hdr_iov, iovcnt);
  88     size_t proto_offset = l2hdr_len - sizeof(proto);
  89
  90     if (size < proto_offset) {
  91         return ETH_P_UNKNOWN;
  92     }
  93
  94     copied = iov_to_buf(l2hdr_iov, iovcnt, proto_offset,
  95                         &proto, sizeof(proto));
  96
  97     return (copied == sizeof(proto)) ? be16_to_cpu(proto) : ETH_P_UNKNOWN;
  98 }
  99
 100 static bool
 101 _eth_copy_chunk(size_t input_size,
 102                 const struct iovec *iov, int iovcnt,
 103                 size_t offset, size_t length,
 104                 void *buffer)
 105 {
 106     size_t copied;
 107
 108     if (input_size < offset) {
 109         return false;
 110     }
 111
 112     copied = iov_to_buf(iov, iovcnt, offset, buffer, length);
 113
 114     if (copied < length) {
 115         return false;
 116     }
 117
 118     return true;
 119 }
 120
 121 static bool
 122 _eth_tcp_has_data(bool is_ip4,
 123                   const struct ip_header  *ip4_hdr,
 124                   const struct ip6_header *ip6_hdr,
 125                   size_t full_ip6hdr_len,
 126                   const struct tcp_header *tcp)
 127 {
 128     uint32_t l4len;
 129
 130     if (is_ip4) {
 131         l4len = be16_to_cpu(ip4_hdr->ip_len) - IP_HDR_GET_LEN(ip4_hdr);
 132     } else {
 133         size_t opts_len = full_ip6hdr_len - sizeof(struct ip6_header);
 134         l4len = be16_to_cpu(ip6_hdr->ip6_ctlun.ip6_un1.ip6_un1_plen) - opts_len;
 135     }
 136
 137     return l4len > TCP_HEADER_DATA_OFFSET(tcp);
 138 }
 139
 140 void eth_get_protocols(const struct iovec *iov, int iovcnt,
 141                        bool *isip4, bool *isip6,
 142                        bool *isudp, bool *istcp,
 143                        size_t *l3hdr_off,
 144                        size_t *l4hdr_off,
 145                        size_t *l5hdr_off,
 146                        eth_ip6_hdr_info *ip6hdr_info,
 147                        eth_ip4_hdr_info *ip4hdr_info,
 148                        eth_l4_hdr_info  *l4hdr_info)
 149 {
 150     int proto;
 151     bool fragment = false;
 152     size_t l2hdr_len = eth_get_l2_hdr_length_iov(iov, iovcnt);
 153     size_t input_size = iov_size(iov, iovcnt);
 154     size_t copied;
 155
 156     *isip4 = *isip6 = *isudp = *istcp = false;
 157
 158     proto = eth_get_l3_proto(iov, iovcnt, l2hdr_len);
 159
 160     *l3hdr_off = l2hdr_len;
 161
 162     if (proto == ETH_P_IP) {
 163         struct ip_header *iphdr = &ip4hdr_info->ip4_hdr;
 164
 165         if (input_size < l2hdr_len) {
 166             return;
 167         }
 168
 169         copied = iov_to_buf(iov, iovcnt, l2hdr_len, iphdr, sizeof(*iphdr));
 170
 171         *isip4 = true;
 172
 173         if (copied < sizeof(*iphdr)) {
 174             return;
 175         }
 176
 177         if (IP_HEADER_VERSION(iphdr) == IP_HEADER_VERSION_4) {
 178             if (iphdr->ip_p == IP_PROTO_TCP) {
 179                 *istcp = true;
 180             } else if (iphdr->ip_p == IP_PROTO_UDP) {
 181                 *isudp = true;
 182             }
 183         }
 184
 185         ip4hdr_info->fragment = IP4_IS_FRAGMENT(iphdr);
 186         *l4hdr_off = l2hdr_len + IP_HDR_GET_LEN(iphdr);
 187
 188         fragment = ip4hdr_info->fragment;
 189     } else if (proto == ETH_P_IPV6) {
 190
 191         *isip6 = true;
 192         if (eth_parse_ipv6_hdr(iov, iovcnt, l2hdr_len,
 193                                ip6hdr_info)) {
 194             if (ip6hdr_info->l4proto == IP_PROTO_TCP) {
 195                 *istcp = true;
 196             } else if (ip6hdr_info->l4proto == IP_PROTO_UDP) {
 197                 *isudp = true;
 198             }
 199         } else {
 200             return;
 201         }
 202
 203         *l4hdr_off = l2hdr_len + ip6hdr_info->full_hdr_len;
 204         fragment = ip6hdr_info->fragment;
 205     }
 206
 207     if (!fragment) {
 208         if (*istcp) {
 209             *istcp = _eth_copy_chunk(input_size,
 210                                      iov, iovcnt,
 211                                      *l4hdr_off, sizeof(l4hdr_info->hdr.tcp),
 212                                      &l4hdr_info->hdr.tcp);
 213
 214             if (*istcp) {
 215                 *l5hdr_off = *l4hdr_off +
 216                     TCP_HEADER_DATA_OFFSET(&l4hdr_info->hdr.tcp);
 217
 218                 l4hdr_info->has_tcp_data =
 219                     _eth_tcp_has_data(proto == ETH_P_IP,
 220                                       &ip4hdr_info->ip4_hdr,
 221                                       &ip6hdr_info->ip6_hdr,
 222                                       *l4hdr_off - *l3hdr_off,
 223                                       &l4hdr_info->hdr.tcp);
 224             }
 225         } else if (*isudp) {
 226             *isudp = _eth_copy_chunk(input_size,
 227                                      iov, iovcnt,
 228                                      *l4hdr_off, sizeof(l4hdr_info->hdr.udp),
 229                                      &l4hdr_info->hdr.udp);
 230             *l5hdr_off = *l4hdr_off + sizeof(l4hdr_info->hdr.udp);
 231         }
 232     }
 233 }
 234
 235 size_t
 236 eth_strip_vlan(const struct iovec *iov, int iovcnt, size_t iovoff,
 237                uint8_t *new_ehdr_buf,
 238                uint16_t *payload_offset, uint16_t *tci)
 239 {
 240     struct vlan_header vlan_hdr;
 241     struct eth_header *new_ehdr = (struct eth_header *) new_ehdr_buf;
 242
 243     size_t copied = iov_to_buf(iov, iovcnt, iovoff,
 244                                new_ehdr, sizeof(*new_ehdr));
 245
 246     if (copied < sizeof(*new_ehdr)) {
 247         return 0;
 248     }
 249
 250     switch (be16_to_cpu(new_ehdr->h_proto)) {
 251     case ETH_P_VLAN:
 252     case ETH_P_DVLAN:
 253         copied = iov_to_buf(iov, iovcnt, iovoff + sizeof(*new_ehdr),
 254                             &vlan_hdr, sizeof(vlan_hdr));
 255
 256         if (copied < sizeof(vlan_hdr)) {
 257             return 0;
 258         }
 259
 260         new_ehdr->h_proto = vlan_hdr.h_proto;
 261
 262         *tci = be16_to_cpu(vlan_hdr.h_tci);
 263         *payload_offset = iovoff + sizeof(*new_ehdr) + sizeof(vlan_hdr);
 264
 265         if (be16_to_cpu(new_ehdr->h_proto) == ETH_P_VLAN) {
 266
 267             copied = iov_to_buf(iov, iovcnt, *payload_offset,
 268                                 PKT_GET_VLAN_HDR(new_ehdr), sizeof(vlan_hdr));
 269
 270             if (copied < sizeof(vlan_hdr)) {
 271                 return 0;
 272             }
 273
 274             *payload_offset += sizeof(vlan_hdr);
 275
 276             return sizeof(struct eth_header) + sizeof(struct vlan_header);
 277         } else {
 278             return sizeof(struct eth_header);
 279         }
 280     default:
 281         return 0;
 282     }
 283 }
 284
 285 size_t
 286 eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff,
 287                   uint16_t vet, uint8_t *new_ehdr_buf,
 288                   uint16_t *payload_offset, uint16_t *tci)
 289 {
 290     struct vlan_header vlan_hdr;
 291     struct eth_header *new_ehdr = (struct eth_header *) new_ehdr_buf;
 292
 293     size_t copied = iov_to_buf(iov, iovcnt, iovoff,
 294                                new_ehdr, sizeof(*new_ehdr));
 295
 296     if (copied < sizeof(*new_ehdr)) {
 297         return 0;
 298     }
 299
 300     if (be16_to_cpu(new_ehdr->h_proto) == vet) {
 301         copied = iov_to_buf(iov, iovcnt, iovoff + sizeof(*new_ehdr),
 302                             &vlan_hdr, sizeof(vlan_hdr));
 303
 304         if (copied < sizeof(vlan_hdr)) {
 305             return 0;
 306         }
 307
 308         new_ehdr->h_proto = vlan_hdr.h_proto;
 309
 310         *tci = be16_to_cpu(vlan_hdr.h_tci);
 311         *payload_offset = iovoff + sizeof(*new_ehdr) + sizeof(vlan_hdr);
 312         return sizeof(struct eth_header);
 313     }
 314
 315     return 0;
 316 }
 317
 318 void
 319 eth_setup_ip4_fragmentation(const void *l2hdr, size_t l2hdr_len,
 320                             void *l3hdr, size_t l3hdr_len,
 321                             size_t l3payload_len,
 322                             size_t frag_offset, bool more_frags)
 323 {
 324     const struct iovec l2vec = {
 325         .iov_base = (void *) l2hdr,
 326         .iov_len = l2hdr_len
 327     };
 328
 329     if (eth_get_l3_proto(&l2vec, 1, l2hdr_len) == ETH_P_IP) {
 330         uint16_t orig_flags;
 331         struct ip_header *iphdr = (struct ip_header *) l3hdr;
 332         uint16_t frag_off_units = frag_offset / IP_FRAG_UNIT_SIZE;
 333         uint16_t new_ip_off;
 334
 335         assert(frag_offset % IP_FRAG_UNIT_SIZE == 0);
 336         assert((frag_off_units & ~IP_OFFMASK) == 0);
 337
 338         orig_flags = be16_to_cpu(iphdr->ip_off) & ~(IP_OFFMASK|IP_MF);
 339         new_ip_off = frag_off_units | orig_flags  | (more_frags ? IP_MF : 0);
 340         iphdr->ip_off = cpu_to_be16(new_ip_off);
 341         iphdr->ip_len = cpu_to_be16(l3payload_len + l3hdr_len);
 342     }
 343 }
 344
 345 void
 346 eth_fix_ip4_checksum(void *l3hdr, size_t l3hdr_len)
 347 {
 348     struct ip_header *iphdr = (struct ip_header *) l3hdr;
 349     iphdr->ip_sum = 0;
 350     iphdr->ip_sum = cpu_to_be16(net_raw_checksum(l3hdr, l3hdr_len));
 351 }
 352
 353 uint32_t
 354 eth_calc_ip4_pseudo_hdr_csum(struct ip_header *iphdr,
 355                              uint16_t csl,
 356                              uint32_t *cso)
 357 {
 358     struct ip_pseudo_header ipph;
 359     ipph.ip_src = iphdr->ip_src;
 360     ipph.ip_dst = iphdr->ip_dst;
 361     ipph.ip_payload = cpu_to_be16(csl);
 362     ipph.ip_proto = iphdr->ip_p;
 363     ipph.zeros = 0;
 364     *cso = sizeof(ipph);
 365     return net_checksum_add(*cso, (uint8_t *) &ipph);
 366 }
 367
 368 uint32_t
 369 eth_calc_ip6_pseudo_hdr_csum(struct ip6_header *iphdr,
 370                              uint16_t csl,
 371                              uint8_t l4_proto,
 372                              uint32_t *cso)
 373 {
 374     struct ip6_pseudo_header ipph;
 375     ipph.ip6_src = iphdr->ip6_src;
 376     ipph.ip6_dst = iphdr->ip6_dst;
 377     ipph.len = cpu_to_be16(csl);
 378     ipph.zero[0] = 0;
 379     ipph.zero[1] = 0;
 380     ipph.zero[2] = 0;
 381     ipph.next_hdr = l4_proto;
 382     *cso = sizeof(ipph);
 383     return net_checksum_add(*cso, (uint8_t *)&ipph);
 384 }
 385
 386 static bool
 387 eth_is_ip6_extension_header_type(uint8_t hdr_type)
 388 {
 389     switch (hdr_type) {
 390     case IP6_HOP_BY_HOP:
 391     case IP6_ROUTING:
 392     case IP6_FRAGMENT:
 393     case IP6_ESP:
 394     case IP6_AUTHENTICATION:
 395     case IP6_DESTINATON:
 396     case IP6_MOBILITY:
 397         return true;
 398     default:
 399         return false;
 400     }
 401 }
 402
 403 static bool
 404 _eth_get_rss_ex_dst_addr(const struct iovec *pkt, int pkt_frags,
 405                         size_t rthdr_offset,
 406                         struct ip6_ext_hdr *ext_hdr,
 407                         struct in6_address *dst_addr)
 408 {
 409     struct ip6_ext_hdr_routing *rthdr = (struct ip6_ext_hdr_routing *) ext_hdr;
 410
 411     if ((rthdr->rtype == 2) &&
 412         (rthdr->len == sizeof(struct in6_address) / 8) &&
 413         (rthdr->segleft == 1)) {
 414
 415         size_t input_size = iov_size(pkt, pkt_frags);
 416         size_t bytes_read;
 417
 418         if (input_size < rthdr_offset + sizeof(*ext_hdr)) {
 419             return false;
 420         }
 421
 422         bytes_read = iov_to_buf(pkt, pkt_frags,
 423                                 rthdr_offset + sizeof(*ext_hdr),
 424                                 dst_addr, sizeof(*dst_addr));
 425
 426         return bytes_read == sizeof(dst_addr);
 427     }
 428
 429     return false;
 430 }
 431
 432 static bool
 433 _eth_get_rss_ex_src_addr(const struct iovec *pkt, int pkt_frags,
 434                         size_t dsthdr_offset,
 435                         struct ip6_ext_hdr *ext_hdr,
 436                         struct in6_address *src_addr)
 437 {
 438     size_t bytes_left = (ext_hdr->ip6r_len + 1) * 8 - sizeof(*ext_hdr);
 439     struct ip6_option_hdr opthdr;
 440     size_t opt_offset = dsthdr_offset + sizeof(*ext_hdr);
 441
 442     while (bytes_left > sizeof(opthdr)) {
 443         size_t input_size = iov_size(pkt, pkt_frags);
 444         size_t bytes_read, optlen;
 445
 446         if (input_size < opt_offset) {
 447             return false;
 448         }
 449
 450         bytes_read = iov_to_buf(pkt, pkt_frags, opt_offset,
 451                                 &opthdr, sizeof(opthdr));
 452
 453         if (bytes_read != sizeof(opthdr)) {
 454             return false;
 455         }
 456
 457         optlen = (opthdr.type == IP6_OPT_PAD1) ? 1
 458                                                : (opthdr.len + sizeof(opthdr));
 459
 460         if (optlen > bytes_left) {
 461             return false;
 462         }
 463
 464         if (opthdr.type == IP6_OPT_HOME) {
 465             size_t input_size = iov_size(pkt, pkt_frags);
 466
 467             if (input_size < opt_offset + sizeof(opthdr)) {
 468                 return false;
 469             }
 470
 471             bytes_read = iov_to_buf(pkt, pkt_frags,
 472                                     opt_offset + sizeof(opthdr),
 473                                     src_addr, sizeof(*src_addr));
 474
 475             return bytes_read == sizeof(src_addr);
 476         }
 477
 478         opt_offset += optlen;
 479         bytes_left -= optlen;
 480     }
 481
 482     return false;
 483 }
 484
 485 bool eth_parse_ipv6_hdr(const struct iovec *pkt, int pkt_frags,
 486                         size_t ip6hdr_off, eth_ip6_hdr_info *info)
 487 {
 488     struct ip6_ext_hdr ext_hdr;
 489     size_t bytes_read;
 490     uint8_t curr_ext_hdr_type;
 491     size_t input_size = iov_size(pkt, pkt_frags);
 492
 493     info->rss_ex_dst_valid = false;
 494     info->rss_ex_src_valid = false;
 495     info->fragment = false;
 496
 497     if (input_size < ip6hdr_off) {
 498         return false;
 499     }
 500
 501     bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off,
 502                             &info->ip6_hdr, sizeof(info->ip6_hdr));
 503     if (bytes_read < sizeof(info->ip6_hdr)) {
 504         return false;
 505     }
 506
 507     info->full_hdr_len = sizeof(struct ip6_header);
 508
 509     curr_ext_hdr_type = info->ip6_hdr.ip6_nxt;
 510
 511     if (!eth_is_ip6_extension_header_type(curr_ext_hdr_type)) {
 512         info->l4proto = info->ip6_hdr.ip6_nxt;
 513         info->has_ext_hdrs = false;
 514         return true;
 515     }
 516
 517     info->has_ext_hdrs = true;
 518
 519     do {
 520         if (input_size < ip6hdr_off + info->full_hdr_len) {
 521             return false;
 522         }
 523
 524         bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off + info->full_hdr_len,
 525                                 &ext_hdr, sizeof(ext_hdr));
 526
 527         if (bytes_read < sizeof(ext_hdr)) {
 528             return false;
 529         }
 530
 531         if (curr_ext_hdr_type == IP6_ROUTING) {
 532             info->rss_ex_dst_valid =
 533                 _eth_get_rss_ex_dst_addr(pkt, pkt_frags,
 534                                          ip6hdr_off + info->full_hdr_len,
 535                                          &ext_hdr, &info->rss_ex_dst);
 536         } else if (curr_ext_hdr_type == IP6_DESTINATON) {
 537             info->rss_ex_src_valid =
 538                 _eth_get_rss_ex_src_addr(pkt, pkt_frags,
 539                                          ip6hdr_off + info->full_hdr_len,
 540                                          &ext_hdr, &info->rss_ex_src);
 541         } else if (curr_ext_hdr_type == IP6_FRAGMENT) {
 542             info->fragment = true;
 543         }
 544
 545         info->full_hdr_len += (ext_hdr.ip6r_len + 1) * IP6_EXT_GRANULARITY;
 546         curr_ext_hdr_type = ext_hdr.ip6r_nxt;
 547     } while (eth_is_ip6_extension_header_type(curr_ext_hdr_type));
 548
 549     info->l4proto = ext_hdr.ip6r_nxt;
 550     return true;
 551 }