pcap_io.h

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * Copyright 2009 - 2013 Daniel Borkmann.
   4  * Copyright 2010 Emmanuel Roullit.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #ifndef PCAP_IO_H
   9 #define PCAP_IO_H
  10
  11 #include <unistd.h>
  12 #include <stdint.h>
  13 #include <stdbool.h>
  14 #include <errno.h>
  15 #include <sys/time.h>
  16 #include <linux/if_packet.h>
  17
  18 #include "built_in.h"
  19 #include "die.h"
  20 #include "xio.h"
  21
  22 #define TCPDUMP_MAGIC                           0xa1b2c3d4
  23 #define ORIGINAL_TCPDUMP_MAGIC                  TCPDUMP_MAGIC
  24 #define NSEC_TCPDUMP_MAGIC                      0xa1b23c4d
  25 #define KUZNETZOV_TCPDUMP_MAGIC                 0xa1b2cd34
  26 #define BORKMANN_TCPDUMP_MAGIC                  0xa1e2cb12
  27
  28 #define PCAP_VERSION_MAJOR                      2
  29 #define PCAP_VERSION_MINOR                      4
  30 #define PCAP_DEFAULT_SNAPSHOT_LEN               65535
  31
  32 #define PCAP_TSOURCE_SOFTWARE                   1
  33 #define PCAP_TSOURCE_SYS_HARDWARE               2
  34 #define PCAP_TSOURCE_RAW_HARDWARE               3
  35
  36 #define LINKTYPE_EN10MB                         1   /* Ethernet (10Mb) */
  37 #define LINKTYPE_IEEE802_11                     105 /* IEEE 802.11 wireless */
  38
  39 struct pcap_filehdr {
  40         uint32_t magic;
  41         uint16_t version_major;
  42         uint16_t version_minor;
  43         int32_t  thiszone;
  44         uint32_t sigfigs;
  45         uint32_t snaplen;
  46         uint32_t linktype;
  47 };
  48
  49 struct pcap_timeval {
  50         int32_t tv_sec;
  51         int32_t tv_usec;
  52 };
  53
  54 struct pcap_timeval_ns {
  55         int32_t tv_sec;
  56         int32_t tv_nsec;
  57 };
  58
  59 struct pcap_pkthdr {
  60         struct pcap_timeval ts;
  61         uint32_t caplen;
  62         uint32_t len;
  63 };
  64
  65 struct pcap_pkthdr_ns {
  66         struct pcap_timeval_ns ts;
  67         uint32_t caplen;
  68         uint32_t len;
  69 };
  70
  71 struct pcap_pkthdr_kuz {
  72         struct pcap_timeval ts;
  73         uint32_t caplen;
  74         uint32_t len;
  75         uint32_t ifindex;
  76         uint16_t protocol;
  77         uint8_t pkttype;
  78 };
  79
  80 struct pcap_pkthdr_bkm {
  81         struct pcap_timeval_ns ts;
  82         uint32_t caplen;
  83         uint32_t len;
  84         uint16_t tsource;
  85         uint16_t ifindex;
  86         uint16_t protocol;
  87         uint8_t hatype;
  88         uint8_t pkttype;
  89 };
  90
  91 typedef union {
  92         struct pcap_pkthdr      ppo;
  93         struct pcap_pkthdr_ns   ppn;
  94         struct pcap_pkthdr_kuz  ppk;
  95         struct pcap_pkthdr_bkm  ppb;
  96         uint8_t                 raw;
  97 } pcap_pkthdr_t;
  98
  99 enum pcap_type {
 100         DEFAULT           =     ORIGINAL_TCPDUMP_MAGIC,
 101         NSEC              =     NSEC_TCPDUMP_MAGIC,
 102         KUZNETZOV         =     KUZNETZOV_TCPDUMP_MAGIC,
 103         BORKMANN          =     BORKMANN_TCPDUMP_MAGIC,
 104
 105         DEFAULT_SWAPPED   =     ___constant_swab32(ORIGINAL_TCPDUMP_MAGIC),
 106         NSEC_SWAPPED      =     ___constant_swab32(NSEC_TCPDUMP_MAGIC),
 107         KUZNETZOV_SWAPPED =     ___constant_swab32(KUZNETZOV_TCPDUMP_MAGIC),
 108         BORKMANN_SWAPPED  =     ___constant_swab32(BORKMANN_TCPDUMP_MAGIC),
 109 };
 110
 111 enum pcap_ops_groups {
 112         PCAP_OPS_RW = 0,
 113         PCAP_OPS_SG,
 114         PCAP_OPS_MM,
 115 };
 116
 117 enum pcap_mode {
 118         PCAP_MODE_RD = 0,
 119         PCAP_MODE_WR,
 120 };
 121
 122 struct pcap_file_ops {
 123         void (*init_once_pcap)(void);
 124         int (*pull_fhdr_pcap)(int fd, uint32_t *magic, uint32_t *linktype);
 125         int (*push_fhdr_pcap)(int fd, uint32_t magic, uint32_t linktype);
 126         int (*prepare_access_pcap)(int fd, enum pcap_mode mode, bool jumbo);
 127         ssize_t (*write_pcap)(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
 128                               const uint8_t *packet, size_t len);
 129         ssize_t (*read_pcap)(int fd, pcap_pkthdr_t *phdr, enum pcap_type type,
 130                              uint8_t *packet, size_t len);
 131         void (*prepare_close_pcap)(int fd, enum pcap_mode mode);
 132         void (*fsync_pcap)(int fd);
 133 };
 134
 135 extern const struct pcap_file_ops pcap_rw_ops;
 136 extern const struct pcap_file_ops pcap_sg_ops;
 137 extern const struct pcap_file_ops pcap_mm_ops;
 138
 139 static inline uint16_t tp_to_pcap_tsource(uint32_t status)
 140 {
 141         if (status & TP_STATUS_TS_RAW_HARDWARE)
 142                 return PCAP_TSOURCE_RAW_HARDWARE;
 143         else if (status & TP_STATUS_TS_SYS_HARDWARE)
 144                 return PCAP_TSOURCE_SYS_HARDWARE;
 145         else if (status & TP_STATUS_TS_SOFTWARE)
 146                 return PCAP_TSOURCE_SOFTWARE;
 147         else
 148                 return 0;
 149 }
 150
 151 static inline void pcap_check_magic(uint32_t magic)
 152 {
 153         switch (magic) {
 154
 155         case ORIGINAL_TCPDUMP_MAGIC:
 156         case NSEC_TCPDUMP_MAGIC:
 157         case KUZNETZOV_TCPDUMP_MAGIC:
 158         case BORKMANN_TCPDUMP_MAGIC:
 159
 160         case ___constant_swab32(ORIGINAL_TCPDUMP_MAGIC):
 161         case ___constant_swab32(NSEC_TCPDUMP_MAGIC):
 162         case ___constant_swab32(KUZNETZOV_TCPDUMP_MAGIC):
 163         case ___constant_swab32(BORKMANN_TCPDUMP_MAGIC):
 164                 break;
 165
 166         default:
 167                 panic("This file has not a valid pcap header\n");
 168         }
 169 }
 170
 171 static inline bool pcap_magic_is_swapped(uint32_t magic)
 172 {
 173         bool swapped = false;
 174
 175         switch (magic) {
 176         case ___constant_swab32(ORIGINAL_TCPDUMP_MAGIC):
 177         case ___constant_swab32(NSEC_TCPDUMP_MAGIC):
 178         case ___constant_swab32(KUZNETZOV_TCPDUMP_MAGIC):
 179         case ___constant_swab32(BORKMANN_TCPDUMP_MAGIC):
 180                 swapped = true;
 181         }
 182
 183         return swapped;
 184 }
 185
 186 static inline u32 pcap_get_length(pcap_pkthdr_t *phdr, enum pcap_type type)
 187 {
 188         switch (type) {
 189 #define CASE_RET_CAPLEN(what, member, swap) \
 190         case (what): \
 191                 return (swap ? ___constant_swab32(phdr->member.caplen) : \
 192                         phdr->member.caplen)
 193
 194         CASE_RET_CAPLEN(DEFAULT, ppo, 0);
 195         CASE_RET_CAPLEN(NSEC, ppn, 0);
 196         CASE_RET_CAPLEN(KUZNETZOV, ppk, 0);
 197         CASE_RET_CAPLEN(BORKMANN, ppb, 0);
 198
 199         CASE_RET_CAPLEN(DEFAULT_SWAPPED, ppo, 1);
 200         CASE_RET_CAPLEN(NSEC_SWAPPED, ppn, 1);
 201         CASE_RET_CAPLEN(KUZNETZOV_SWAPPED, ppk, 1);
 202         CASE_RET_CAPLEN(BORKMANN_SWAPPED, ppb, 1);
 203
 204         default:
 205                 bug();
 206         }
 207 }
 208
 209 static inline void pcap_set_length(pcap_pkthdr_t *phdr, enum pcap_type type, u32 len)
 210 {
 211         switch (type) {
 212 #define CASE_SET_CAPLEN(what, member, swap) \
 213         case (what): \
 214                 phdr->member.caplen = (swap ? ___constant_swab32(len) : len); \
 215                 break
 216
 217         CASE_SET_CAPLEN(DEFAULT, ppo, 0);
 218         CASE_SET_CAPLEN(NSEC, ppn, 0);
 219         CASE_SET_CAPLEN(KUZNETZOV, ppk, 0);
 220         CASE_SET_CAPLEN(BORKMANN, ppb, 0);
 221
 222         CASE_SET_CAPLEN(DEFAULT_SWAPPED, ppo, 1);
 223         CASE_SET_CAPLEN(NSEC_SWAPPED, ppn, 1);
 224         CASE_SET_CAPLEN(KUZNETZOV_SWAPPED, ppk, 1);
 225         CASE_SET_CAPLEN(BORKMANN_SWAPPED, ppb, 1);
 226
 227         default:
 228                 bug();
 229         }
 230 }
 231
 232 static inline u32 pcap_get_hdr_length(pcap_pkthdr_t *phdr, enum pcap_type type)
 233 {
 234         switch (type) {
 235 #define CASE_RET_HDRLEN(what, member) \
 236         case (what): \
 237                 return sizeof(phdr->member)
 238
 239         CASE_RET_HDRLEN(DEFAULT, ppo);
 240         CASE_RET_HDRLEN(NSEC, ppn);
 241         CASE_RET_HDRLEN(KUZNETZOV, ppk);
 242         CASE_RET_HDRLEN(BORKMANN, ppb);
 243
 244         CASE_RET_HDRLEN(DEFAULT_SWAPPED, ppo);
 245         CASE_RET_HDRLEN(NSEC_SWAPPED, ppn);
 246         CASE_RET_HDRLEN(KUZNETZOV_SWAPPED, ppk);
 247         CASE_RET_HDRLEN(BORKMANN_SWAPPED, ppb);
 248
 249         default:
 250                 bug();
 251         }
 252 }
 253
 254 static inline u32 pcap_get_total_length(pcap_pkthdr_t *phdr, enum pcap_type type)
 255 {
 256         switch (type) {
 257 #define CASE_RET_TOTLEN(what, member, swap) \
 258         case (what): \
 259                 return ((swap ? ___constant_swab32(phdr->member.caplen) : \
 260                          phdr->member.caplen) + sizeof(phdr->member))
 261
 262         CASE_RET_TOTLEN(DEFAULT, ppo, 0);
 263         CASE_RET_TOTLEN(NSEC, ppn, 0);
 264         CASE_RET_TOTLEN(KUZNETZOV, ppk, 0);
 265         CASE_RET_TOTLEN(BORKMANN, ppb, 0);
 266
 267         CASE_RET_TOTLEN(DEFAULT_SWAPPED, ppo, 1);
 268         CASE_RET_TOTLEN(NSEC_SWAPPED, ppn, 1);
 269         CASE_RET_TOTLEN(KUZNETZOV_SWAPPED, ppk, 1);
 270         CASE_RET_TOTLEN(BORKMANN_SWAPPED, ppb, 1);
 271
 272         default:
 273                 bug();
 274         }
 275 }
 276
 277 static inline void tpacket_hdr_to_pcap_pkthdr(struct tpacket2_hdr *thdr,
 278                                               struct sockaddr_ll *sll,
 279                                               pcap_pkthdr_t *phdr,
 280                                               enum pcap_type type)
 281 {
 282         switch (type) {
 283         case DEFAULT:
 284                 phdr->ppo.ts.tv_sec = thdr->tp_sec;
 285                 phdr->ppo.ts.tv_usec = thdr->tp_nsec / 1000;
 286                 phdr->ppo.caplen = thdr->tp_snaplen;
 287                 phdr->ppo.len = thdr->tp_len;
 288                 break;
 289
 290         case DEFAULT_SWAPPED:
 291                 phdr->ppo.ts.tv_sec = ___constant_swab32(thdr->tp_sec);
 292                 phdr->ppo.ts.tv_usec = ___constant_swab32(thdr->tp_nsec / 1000);
 293                 phdr->ppo.caplen = ___constant_swab32(thdr->tp_snaplen);
 294                 phdr->ppo.len = ___constant_swab32(thdr->tp_len);
 295                 break;
 296
 297         case NSEC:
 298                 phdr->ppn.ts.tv_sec = thdr->tp_sec;
 299                 phdr->ppn.ts.tv_nsec = thdr->tp_nsec;
 300                 phdr->ppn.caplen = thdr->tp_snaplen;
 301                 phdr->ppn.len = thdr->tp_len;
 302                 break;
 303
 304         case NSEC_SWAPPED:
 305                 phdr->ppn.ts.tv_sec = ___constant_swab32(thdr->tp_sec);
 306                 phdr->ppn.ts.tv_nsec = ___constant_swab32(thdr->tp_nsec);
 307                 phdr->ppn.caplen = ___constant_swab32(thdr->tp_snaplen);
 308                 phdr->ppn.len = ___constant_swab32(thdr->tp_len);
 309                 break;
 310
 311         case KUZNETZOV:
 312                 phdr->ppk.ts.tv_sec = thdr->tp_sec;
 313                 phdr->ppk.ts.tv_usec = thdr->tp_nsec / 1000;
 314                 phdr->ppk.caplen = thdr->tp_snaplen;
 315                 phdr->ppk.len = thdr->tp_len;
 316                 phdr->ppk.ifindex = sll->sll_ifindex;
 317                 phdr->ppk.protocol = sll->sll_protocol;
 318                 phdr->ppk.pkttype = sll->sll_pkttype;
 319                 break;
 320
 321         case KUZNETZOV_SWAPPED:
 322                 phdr->ppk.ts.tv_sec = ___constant_swab32(thdr->tp_sec);
 323                 phdr->ppk.ts.tv_usec = ___constant_swab32(thdr->tp_nsec / 1000);
 324                 phdr->ppk.caplen = ___constant_swab32(thdr->tp_snaplen);
 325                 phdr->ppk.len = ___constant_swab32(thdr->tp_len);
 326                 phdr->ppk.ifindex = ___constant_swab32(sll->sll_ifindex);
 327                 phdr->ppk.protocol = ___constant_swab16(sll->sll_protocol);
 328                 phdr->ppk.pkttype = sll->sll_pkttype;
 329                 break;
 330
 331         case BORKMANN:
 332                 phdr->ppb.ts.tv_sec = thdr->tp_sec;
 333                 phdr->ppb.ts.tv_nsec = thdr->tp_nsec;
 334                 phdr->ppb.caplen = thdr->tp_snaplen;
 335                 phdr->ppb.len = thdr->tp_len;
 336                 phdr->ppb.tsource = tp_to_pcap_tsource(thdr->tp_status);
 337                 phdr->ppb.ifindex = (u16) sll->sll_ifindex;
 338                 phdr->ppb.protocol = sll->sll_protocol;
 339                 phdr->ppb.hatype = sll->sll_hatype;
 340                 phdr->ppb.pkttype = sll->sll_pkttype;
 341                 break;
 342
 343         case BORKMANN_SWAPPED:
 344                 phdr->ppb.ts.tv_sec = ___constant_swab32(thdr->tp_sec);
 345                 phdr->ppb.ts.tv_nsec = ___constant_swab32(thdr->tp_nsec);
 346                 phdr->ppb.caplen = ___constant_swab32(thdr->tp_snaplen);
 347                 phdr->ppb.len = ___constant_swab32(thdr->tp_len);
 348                 phdr->ppb.tsource = ___constant_swab16(tp_to_pcap_tsource(thdr->tp_status));
 349                 phdr->ppb.ifindex = ___constant_swab16((u16) sll->sll_ifindex);
 350                 phdr->ppb.protocol = ___constant_swab16(sll->sll_protocol);
 351                 phdr->ppb.hatype = sll->sll_hatype;
 352                 phdr->ppb.pkttype = sll->sll_pkttype;
 353                 break;
 354
 355         default:
 356                 bug();
 357         }
 358 }
 359
 360 static inline void pcap_pkthdr_to_tpacket_hdr(pcap_pkthdr_t *phdr,
 361                                               enum pcap_type type,
 362                                               struct tpacket2_hdr *thdr,
 363                                               struct sockaddr_ll *sll)
 364 {
 365         switch (type) {
 366         case DEFAULT:
 367                 thdr->tp_sec = phdr->ppo.ts.tv_sec;
 368                 thdr->tp_nsec = phdr->ppo.ts.tv_usec * 1000;
 369                 thdr->tp_snaplen = phdr->ppo.caplen;
 370                 thdr->tp_len = phdr->ppo.len;
 371                 break;
 372
 373         case DEFAULT_SWAPPED:
 374                 thdr->tp_sec = ___constant_swab32(phdr->ppo.ts.tv_sec);
 375                 thdr->tp_nsec = ___constant_swab32(phdr->ppo.ts.tv_usec) * 1000;
 376                 thdr->tp_snaplen = ___constant_swab32(phdr->ppo.caplen);
 377                 thdr->tp_len = ___constant_swab32(phdr->ppo.len);
 378                 break;
 379
 380         case NSEC:
 381                 thdr->tp_sec = phdr->ppn.ts.tv_sec;
 382                 thdr->tp_nsec = phdr->ppn.ts.tv_nsec;
 383                 thdr->tp_snaplen = phdr->ppn.caplen;
 384                 thdr->tp_len = phdr->ppn.len;
 385                 break;
 386
 387         case NSEC_SWAPPED:
 388                 thdr->tp_sec = ___constant_swab32(phdr->ppn.ts.tv_sec);
 389                 thdr->tp_nsec = ___constant_swab32(phdr->ppn.ts.tv_nsec);
 390                 thdr->tp_snaplen = ___constant_swab32(phdr->ppn.caplen);
 391                 thdr->tp_len = ___constant_swab32(phdr->ppn.len);
 392                 break;
 393
 394         case KUZNETZOV:
 395                 thdr->tp_sec = phdr->ppk.ts.tv_sec;
 396                 thdr->tp_nsec = phdr->ppk.ts.tv_usec * 1000;
 397                 thdr->tp_snaplen = phdr->ppk.caplen;
 398                 thdr->tp_len = phdr->ppk.len;
 399                 break;
 400
 401         case KUZNETZOV_SWAPPED:
 402                 thdr->tp_sec = ___constant_swab32(phdr->ppk.ts.tv_sec);
 403                 thdr->tp_nsec = ___constant_swab32(phdr->ppk.ts.tv_usec) * 1000;
 404                 thdr->tp_snaplen = ___constant_swab32(phdr->ppk.caplen);
 405                 thdr->tp_len = ___constant_swab32(phdr->ppk.len);
 406                 break;
 407
 408         case BORKMANN:
 409                 thdr->tp_sec = phdr->ppb.ts.tv_sec;
 410                 thdr->tp_nsec = phdr->ppb.ts.tv_nsec;
 411                 thdr->tp_snaplen = phdr->ppb.caplen;
 412                 thdr->tp_len = phdr->ppb.len;
 413                 break;
 414
 415         case BORKMANN_SWAPPED:
 416                 thdr->tp_sec = ___constant_swab32(phdr->ppb.ts.tv_sec);
 417                 thdr->tp_nsec = ___constant_swab32(phdr->ppb.ts.tv_nsec);
 418                 thdr->tp_snaplen = ___constant_swab32(phdr->ppb.caplen);
 419                 thdr->tp_len = ___constant_swab32(phdr->ppb.len);
 420                 break;
 421
 422         default:
 423                 bug();
 424         }
 425 }
 426
 427 #define FEATURE_UNKNOWN         (0 << 0)
 428 #define FEATURE_TIMEVAL_MS      (1 << 0)
 429 #define FEATURE_TIMEVAL_NS      (1 << 1)
 430 #define FEATURE_LEN             (1 << 2)
 431 #define FEATURE_CAPLEN          (1 << 3)
 432 #define FEATURE_IFINDEX         (1 << 4)
 433 #define FEATURE_PROTO           (1 << 5)
 434 #define FEATURE_HATYPE          (1 << 6)
 435 #define FEATURE_PKTTYPE         (1 << 7)
 436 #define FEATURE_TSOURCE         (1 << 8)
 437
 438 struct pcap_magic_type {
 439         const uint32_t magic;
 440         const char *desc;
 441         const uint16_t features;
 442 };
 443
 444 static const struct pcap_magic_type pcap_magic_types[] __maybe_unused = {
 445         {
 446                 .magic = ORIGINAL_TCPDUMP_MAGIC,
 447                 .desc = "tcpdump-capable pcap",
 448                 .features = FEATURE_TIMEVAL_MS |
 449                             FEATURE_LEN |
 450                             FEATURE_CAPLEN,
 451         }, {
 452                 .magic = NSEC_TCPDUMP_MAGIC,
 453                 .desc = "tcpdump-capable pcap with ns resolution",
 454                 .features = FEATURE_TIMEVAL_NS |
 455                             FEATURE_LEN |
 456                             FEATURE_CAPLEN,
 457         }, {
 458                 .magic = KUZNETZOV_TCPDUMP_MAGIC,
 459                 .desc = "Alexey Kuznetzov's pcap",
 460                 .features = FEATURE_TIMEVAL_MS |
 461                             FEATURE_LEN |
 462                             FEATURE_CAPLEN |
 463                             FEATURE_IFINDEX |
 464                             FEATURE_PROTO |
 465                             FEATURE_PKTTYPE,
 466         }, {
 467                 .magic = BORKMANN_TCPDUMP_MAGIC,
 468                 .desc = "netsniff-ng pcap",
 469                 .features = FEATURE_TIMEVAL_NS |
 470                             FEATURE_LEN |
 471                             FEATURE_CAPLEN |
 472                             FEATURE_TSOURCE |
 473                             FEATURE_IFINDEX |
 474                             FEATURE_PROTO |
 475                             FEATURE_HATYPE |
 476                             FEATURE_PKTTYPE,
 477         },
 478 };
 479
 480 static inline void pcap_dump_type_features(void)
 481 {
 482         int i;
 483
 484         for (i = 0; i < array_size(pcap_magic_types); ++i) {
 485                 printf("%s:\n", pcap_magic_types[i].desc);
 486                 printf("  magic: 0x%x (swapped: 0x%x)\n",
 487                        pcap_magic_types[i].magic,
 488                        ___constant_swab32(pcap_magic_types[i].magic));
 489                 printf("  features:\n");
 490
 491                 if (pcap_magic_types[i].features == FEATURE_UNKNOWN) {
 492                         printf("    unknown\n");
 493                         continue;
 494                 }
 495
 496                 if (pcap_magic_types[i].features & FEATURE_TIMEVAL_MS)
 497                         printf("    timeval in us\n");
 498                 if (pcap_magic_types[i].features & FEATURE_TIMEVAL_NS)
 499                         printf("    timeval in ns\n");
 500                 if (pcap_magic_types[i].features & FEATURE_TSOURCE)
 501                         printf("    timestamp source\n");
 502                 if (pcap_magic_types[i].features & FEATURE_LEN)
 503                         printf("    packet length\n");
 504                 if (pcap_magic_types[i].features & FEATURE_CAPLEN)
 505                         printf("    packet cap-length\n");
 506                 if (pcap_magic_types[i].features & FEATURE_IFINDEX)
 507                         printf("    packet ifindex\n");
 508                 if (pcap_magic_types[i].features & FEATURE_PROTO)
 509                         printf("    packet protocol\n");
 510                 if (pcap_magic_types[i].features & FEATURE_HATYPE)
 511                         printf("    hardware type\n");
 512                 if (pcap_magic_types[i].features & FEATURE_PKTTYPE)
 513                         printf("    packet type\n");
 514         }
 515 }
 516
 517 static const char *pcap_ops_group_to_str[] __maybe_unused = {
 518         [PCAP_OPS_RW] = "rw",
 519         [PCAP_OPS_SG] = "sg",
 520         [PCAP_OPS_MM] = "mm",
 521 };
 522
 523 static const struct pcap_file_ops *pcap_ops[] __maybe_unused = {
 524         [PCAP_OPS_RW]           =       &pcap_rw_ops,
 525         [PCAP_OPS_SG]           =       &pcap_sg_ops,
 526         [PCAP_OPS_MM]           =       &pcap_mm_ops,
 527 };
 528
 529 static inline void pcap_prepare_header(struct pcap_filehdr *hdr, uint32_t magic,
 530                                        uint32_t linktype, int32_t thiszone,
 531                                        uint32_t snaplen)
 532 {
 533         bool swapped = pcap_magic_is_swapped(magic);
 534
 535         hdr->magic = magic;
 536         hdr->version_major = swapped ? ___constant_swab16(PCAP_VERSION_MAJOR) : PCAP_VERSION_MAJOR;
 537         hdr->version_minor = swapped ? ___constant_swab16(PCAP_VERSION_MINOR) : PCAP_VERSION_MINOR;
 538         hdr->thiszone = swapped ? ___constant_swab32(thiszone)  : thiszone;
 539         hdr->sigfigs = 0;
 540         hdr->snaplen = swapped ? ___constant_swab32(snaplen) : snaplen;
 541         hdr->linktype = swapped ? ___constant_swab32(linktype) : linktype;
 542 }
 543
 544 static inline void pcap_validate_header(const struct pcap_filehdr *hdr)
 545 {
 546         pcap_check_magic(hdr->magic);
 547
 548         switch (hdr->linktype) {
 549         case LINKTYPE_EN10MB:
 550         case LINKTYPE_IEEE802_11:
 551         case ___constant_swab32(LINKTYPE_EN10MB):
 552         case ___constant_swab32(LINKTYPE_IEEE802_11):
 553                 break;
 554         default:
 555                 panic("This file has not a valid pcap header\n");
 556         }
 557
 558         if (unlikely(hdr->version_major != PCAP_VERSION_MAJOR) &&
 559                      ___constant_swab16(hdr->version_major) != PCAP_VERSION_MAJOR)
 560                 panic("This file has not a valid pcap header\n");
 561         if (unlikely(hdr->version_minor != PCAP_VERSION_MINOR) &&
 562                      ___constant_swab16(hdr->version_minor) != PCAP_VERSION_MINOR)
 563                 panic("This file has not a valid pcap header\n");
 564 }
 565
 566 static int pcap_generic_pull_fhdr(int fd, uint32_t *magic,
 567                                   uint32_t *linktype) __maybe_unused;
 568
 569 static int pcap_generic_pull_fhdr(int fd, uint32_t *magic, uint32_t *linktype)
 570 {
 571         ssize_t ret;
 572         struct pcap_filehdr hdr;
 573
 574         ret = read(fd, &hdr, sizeof(hdr));
 575         if (unlikely(ret != sizeof(hdr)))
 576                 return -EIO;
 577
 578         pcap_validate_header(&hdr);
 579
 580         *magic = hdr.magic;
 581         *linktype = hdr.linktype;
 582
 583         return 0;
 584 }
 585
 586 static int pcap_generic_push_fhdr(int fd, uint32_t magic,
 587                                   uint32_t linktype) __maybe_unused;
 588
 589 static int pcap_generic_push_fhdr(int fd, uint32_t magic, uint32_t linktype)
 590 {
 591         ssize_t ret;
 592         struct pcap_filehdr hdr;
 593
 594         memset(&hdr, 0, sizeof(hdr));
 595
 596         pcap_prepare_header(&hdr, magic, linktype, 0, PCAP_DEFAULT_SNAPSHOT_LEN);
 597
 598         ret = write_or_die(fd, &hdr, sizeof(hdr));
 599         if (unlikely(ret != sizeof(hdr)))
 600                 panic("Failed to write pkt file header!\n");
 601
 602         return 0;
 603 }
 604
 605 #endif /* PCAP_IO_H */