The Tcpdump Group git mirrors - libpcap/blob - pcap-dag.c

   1 /*
   2  * pcap-dag.c: Packet capture interface for Endace DAG card.
   3  *
   4  * The functionality of this code attempts to mimic that of pcap-linux as much
   5  * as possible.  This code is compiled in several different ways depending on
   6  * whether DAG_ONLY and HAVE_DAG_API are defined.  If HAVE_DAG_API is not
   7  * defined it should not get compiled in, otherwise if DAG_ONLY is defined then
   8  * the 'dag_' function calls are renamed to 'pcap_' equivalents.  If DAG_ONLY
   9  * is not defined then nothing is altered - the dag_ functions will be
  10  * called as required from their pcap-linux/bpf equivalents.
  11  *
  12  * Author: Richard Littin, Sean Irvine ({richard,sean}@reeltwo.com)
  13  *
  14  * Modifications:
  15  *   2003 May - Jesper Peterson <support@endace.com>
  16  *              Code shuffled around to suit fad-xxx.c structure
  17  *              Added atexit() handler to stop DAG if application is too lazy
  18  */
  19
  20 #ifndef lint
  21 static const char rcsid[] =
  22     "@(#) $Header: /tcpdump/master/libpcap/pcap-dag.c,v 1.1 2003-07-23 05:29:21 guy Exp $ (LBL)";
  23 #endif
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <sys/param.h>                  /* optionally get BSD define */
  30
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <errno.h>
  34
  35 #include "pcap-int.h"
  36
  37 #include <sys/mman.h>
  38 #include <sys/socket.h>
  39
  40 struct mbuf;            /* Squelch compiler warnings on some platforms for */
  41 struct rtentry;         /* declarations in <net/if.h> */
  42 #include <net/if.h>
  43
  44 #include <dagnew.h>
  45 #include <dagapi.h>
  46
  47 #define MAX_DAG_SNAPLEN 2040
  48
  49 typedef struct pcap_dag_node {
  50   struct pcap_dag_node *next;
  51   pcap_t *p;
  52 } pcap_dag_node_t;
  53
  54 static pcap_dag_node_t *pcap_dags = NULL;
  55 static int atexit_handler_installed = 0;
  56
  57 #ifdef DAG_ONLY
  58 /* This code is reguired when compiling for a DAG device only. */
  59 #include "pcap-dag.h"
  60
  61 /* Replace dag function names with pcap equivalent. */
  62 #define dag_stats pcap_stats
  63 #define dag_read pcap_read
  64 #define dag_open_live pcap_open_live
  65 #define dag_platform_finddevs pcap_platform_finddevs
  66 #define dag_setfilter pcap_setfilter
  67 #define dag_set_datalink_platform pcap_set_datalink_platform
  68 #define dag_platform_close pcap_platform_close
  69 #endif /* DAG_ONLY */
  70
  71 static void delete_pcap_dag(pcap_t *p) {
  72   pcap_dag_node_t *curr = NULL, *prev = NULL;
  73
  74   for (prev = NULL, curr = pcap_dags;
  75       curr != NULL && curr->p != p;
  76       prev = curr, curr = curr->next) {
  77     /* empty */
  78   }
  79
  80   if (curr != NULL && curr->p == p) {
  81     if (prev != NULL) {
  82       prev->next = curr->next;
  83     } else {
  84       pcap_dags = curr->next;
  85     }
  86   }
  87 }
  88
  89 /*
  90  * Performs a graceful shutdown of the DAG card and frees dynamic memory held
  91  * in the pcap_t structure.
  92  */
  93
  94 void dag_platform_close(pcap_t *p) {
  95
  96 #ifdef linux
  97   if (p != NULL && p->md.is_dag && p->md.device != NULL) {
  98     if(dag_stop(p->fd) < 0)
  99       fprintf(stderr,"dag_stop %s: %s\n", p->md.device, strerror(errno));
 100     if(dag_close(p->fd) < 0)
 101       fprintf(stderr,"dag_close %s: %s\n", p->md.device, strerror(errno));
 102
 103     free(p->md.device);
 104   }
 105 #else
 106   if (p != NULL && p->md.is_dag) {
 107     if(dag_stop(p->fd) < 0)
 108       fprintf(stderr,"dag_stop: %s\n", strerror(errno));
 109     if(dag_close(p->fd) < 0)
 110       fprintf(stderr,"dag_close: %s\n", strerror(errno));
 111   }
 112 #endif
 113   delete_pcap_dag(p);
 114 }
 115
 116 static void atexit_handler(void) {
 117   while (pcap_dags != NULL) {
 118     dag_platform_close(pcap_dags->p);
 119   }
 120 }
 121
 122 static int new_pcap_dag(pcap_t *p) {
 123   pcap_dag_node_t *node = NULL;
 124
 125   if ((node = malloc(sizeof(pcap_dag_node_t))) == NULL) {
 126     return -1;
 127   }
 128
 129   if (!atexit_handler_installed) {
 130     atexit(atexit_handler);
 131     atexit_handler_installed = 1;
 132   }
 133
 134   node->next = pcap_dags;
 135   node->p = p;
 136
 137   return 0;
 138 }
 139
 140 /*
 141  * Get pointer to the ERF header for the next packet in the input
 142  * stream. This function blocks until a packet becomes available.
 143  */
 144 static dag_record_t *get_next_dag_header(pcap_t *p) {
 145   register dag_record_t *record;
 146   int rlen;
 147
 148   if (p->md.dag_mem_top - p->md.dag_mem_bottom < dag_record_size) {
 149     p->md.dag_mem_top = dag_offset(p->fd, &(p->md.dag_mem_bottom), 0);
 150   }
 151
 152   record = (dag_record_t *)(p->md.dag_mem_base + p->md.dag_mem_bottom);
 153   rlen = ntohs(record->rlen);
 154   while (p->md.dag_mem_top - p->md.dag_mem_bottom < rlen) {
 155     p->md.dag_mem_top = dag_offset(p->fd, &(p->md.dag_mem_bottom), 0);
 156     record = (dag_record_t *)(p->md.dag_mem_base + p->md.dag_mem_bottom);
 157     rlen = ntohs(record->rlen);
 158   }
 159
 160   p->md.dag_mem_bottom += rlen;
 161
 162   return record;
 163 }
 164
 165 /* Size of payload in ATM packets */
 166 #define ATM_CAPTURE_SIZE 48
 167
 168 /* Size of payload of Ethernet packet */
 169 #define ETHERNET_LENGTH(h) min(ntohs((h)->wlen) - 4, ntohs((h)->rlen) - dag_record_size - 2 - (ntohs((h)->wlen) & 0x3))
 170
 171 /* Size of HDLC packet */
 172 #define HDLC_LENGTH(h) min(ntohs((h)->wlen) - 4, ntohs((h)->rlen) - dag_record_size)
 173
 174 #ifndef min
 175 #define min(a, b) ((a) > (b) ? (b) : (a))
 176 #endif
 177
 178 /*
 179  * Swap byte ordering of unsigned long long on a big endian
 180  * machine.
 181  */
 182 static unsigned long long swapll(unsigned long long ull) {
 183 #if (BYTE_ORDER == BIG_ENDIAN)
 184   return ((ull & 0xff00000000000000LL) >> 56) |
 185     ((ull & 0x00ff000000000000LL) >> 40) |
 186     ((ull & 0x0000ff0000000000LL) >> 24) |
 187     ((ull & 0x000000ff00000000LL) >>  8) |
 188     ((ull & 0x00000000ff000000LL) <<  8) |
 189     ((ull & 0x0000000000ff0000LL) << 24) |
 190     ((ull & 0x000000000000ff00LL) << 40) |
 191     ((ull & 0x00000000000000ffLL) << 56) ;
 192 #else
 193   return ull;
 194 #endif
 195 }
 196
 197 /*
 198  *  Read at most max_packets from the capture stream and call the callback
 199  *  for each of them. Returns the number of packets handled or -1 if an
 200  *  error occured.  A blocking
 201  */
 202 int dag_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) {
 203   u_char                *dp = NULL;
 204   int                   packet_len = 0, caplen = 0;
 205   struct pcap_pkthdr    pcap_header;
 206
 207   dag_record_t *header;
 208   register unsigned long long ts;
 209
 210   /* Receive a single packet from the kernel */
 211   header = get_next_dag_header(p);
 212   dp = ((u_char *)header) + dag_record_size;
 213
 214   switch(header->type) {
 215   case TYPE_ATM:
 216     packet_len = ATM_CAPTURE_SIZE;
 217     caplen = ATM_CAPTURE_SIZE;
 218     break;
 219   case TYPE_ETH:
 220     packet_len = ntohs(header->wlen);
 221     caplen = ETHERNET_LENGTH(header);
 222     dp += 2;
 223     break;
 224   case TYPE_HDLC_POS:
 225     packet_len = ntohs(header->wlen);
 226     caplen = HDLC_LENGTH(header);
 227     break;
 228   }
 229
 230   if (caplen > p->snapshot)
 231     caplen = p->snapshot;
 232
 233   /* Run the packet filter if not using kernel filter */
 234   if (p->fcode.bf_insns) {
 235     if (bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen) == 0) {
 236       /* rejected by filter */
 237       return 0;
 238     }
 239   }
 240
 241   /* convert between timestamp formats */
 242   ts = swapll(header->ts);
 243   pcap_header.ts.tv_sec  = ts >> 32;
 244   ts = ((ts &  0xffffffffULL) * 1000 * 1000);
 245   ts += (ts & 0x80000000ULL) << 1; /* rounding */
 246   pcap_header.ts.tv_usec = ts >> 32;
 247   if (pcap_header.ts.tv_usec >= 1000000) {
 248     pcap_header.ts.tv_usec -= 1000000;
 249     pcap_header.ts.tv_sec += 1;
 250   }
 251
 252   /* Fill in our own header data */
 253   pcap_header.caplen = caplen;
 254   pcap_header.len = packet_len;
 255
 256   /*
 257    * Count the packet.
 258    */
 259   p->md.stat.ps_recv++;
 260
 261   /* Call the user supplied callback function */
 262   callback(user, &pcap_header, dp);
 263
 264   return 1;
 265 }
 266
 267 /*
 268  *  Get a handle for a live capture from the given DAG device.  Passing a NULL
 269  *  device will result in a failure.  The promisc flag is ignored because DAG
 270  *  cards are always promiscuous.  The to_ms parameter is also ignored as it is
 271  *  not supported in hardware.
 272  *
 273  *  See also pcap(3).
 274  */
 275 pcap_t *dag_open_live(const char *device, int snaplen, int promisc, int to_ms, char *ebuf) {
 276   char conf[30]; /* dag configure string */
 277   pcap_t *handle;
 278
 279   if (device == NULL) {
 280     snprintf(ebuf, PCAP_ERRBUF_SIZE, "device is NULL: %s", pcap_strerror(errno));
 281     return NULL;
 282   }
 283   /* Allocate a handle for this session. */
 284
 285   handle = malloc(sizeof(*handle));
 286   if (handle == NULL) {
 287     snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc %s: %s", device, pcap_strerror(errno));
 288     return NULL;
 289   }
 290
 291   /* Initialize some components of the pcap structure. */
 292
 293   memset(handle, 0, sizeof(*handle));
 294
 295   if (strstr(device, "/dev") == NULL) {
 296     char * newDev = (char *)malloc(strlen(device) + 6);
 297     newDev[0] = '\0';
 298     strcat(newDev, "/dev/");
 299     strcat(newDev,device);
 300     device = newDev;
 301   }
 302
 303   /* setup device parameters */
 304   if((handle->fd = dag_open((char *)device)) < 0) {
 305     snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_open %s: %s", device, pcap_strerror(errno));
 306     return NULL;
 307   }
 308
 309   /* set the card snap length as specified by the specified snaplen parameter */
 310   if (snaplen > MAX_DAG_SNAPLEN) {
 311     snaplen = MAX_DAG_SNAPLEN;
 312   }
 313   snprintf(conf, 30, "varlen slen=%d", (snaplen % 4) ? (snaplen + 3) & ~3 : snaplen); /* snap len has to be a multiple of 4 */
 314   fprintf(stderr, "Configuring DAG with '%s'.\n", conf);
 315   if(dag_configure(handle->fd, conf) < 0) {
 316     snprintf(ebuf, PCAP_ERRBUF_SIZE,"dag_configure %s: %s\n", device, pcap_strerror(errno));
 317     return NULL;
 318   }
 319
 320   if((handle->md.dag_mem_base = dag_mmap(handle->fd)) == MAP_FAILED) {
 321     snprintf(ebuf, PCAP_ERRBUF_SIZE,"dag_mmap %s: %s\n", device, pcap_strerror(errno));
 322     return NULL;
 323   }
 324
 325   if(dag_start(handle->fd) < 0) {
 326     snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_start %s: %s\n", device, pcap_strerror(errno));
 327     return NULL;
 328   }
 329
 330   /*
 331    * Important! You have to ensure bottom is properly
 332    * initialized to zero on startup, it won't give you
 333    * a compiler warning if you make this mistake!
 334    */
 335   handle->md.dag_mem_bottom = 0;
 336   handle->md.dag_mem_top = 0;
 337   handle->md.is_dag = 1;
 338
 339   handle->snapshot      = snaplen;
 340   /*handle->md.timeout  = to_ms; */
 341
 342 #ifdef linux
 343   if (device) {
 344     handle->md.device = strdup(device);
 345   }
 346
 347   if (handle->md.device == NULL) {
 348     snprintf(ebuf, PCAP_ERRBUF_SIZE, "str_dup %s: %s\n", device, pcap_strerror(errno));
 349     free(handle);
 350     return NULL;
 351   }
 352 #endif
 353
 354   /* set link type */
 355
 356   /* Check the type through a dagapi call.
 357   */
 358   switch(dag_linktype(handle->fd)) {
 359   case TYPE_HDLC_POS:
 360     handle->linktype = DLT_CHDLC;
 361     fprintf(stderr, "Set DAG linktype to %d (DLT_CHDLC)\n", handle->linktype);
 362     break;
 363   case TYPE_ETH:
 364     handle->linktype = DLT_EN10MB;
 365     fprintf(stderr, "Set DAG linktype to %d (DLT_EN10MB)\n", handle->linktype);
 366     break;
 367   case TYPE_ATM:
 368     handle->linktype = DLT_ATM_RFC1483;
 369     fprintf(stderr, "Set DAG linktype to %d (DLT_ATM_RFC1483)\n", handle->linktype);
 370     break;
 371   case TYPE_LEGACY:
 372     handle->linktype = DLT_NULL;
 373     fprintf(stderr, "Set DAG linktype to %d (DLT_NULL)\n", handle->linktype);
 374     break;
 375   default:
 376     snprintf(ebuf, PCAP_ERRBUF_SIZE, "dag_open_live %s: unknown linktype %d\n", device, dag_linktype(handle->fd));
 377     return NULL;
 378   }
 379
 380   handle->bufsize = 0;/*handle->snapshot;*/
 381
 382   if (new_pcap_dag(handle) < 0) {
 383     snprintf(ebuf, PCAP_ERRBUF_SIZE, "new_pcap_dag %s: %s\n", device, pcap_strerror(errno));
 384     return NULL;
 385   }
 386
 387   return handle;
 388 }
 389
 390 int dag_stats(pcap_t *p, struct pcap_stat *ps) {
 391   /* This needs to be filled out correctly.  Hopefully a dagapi call will
 392      provide all necessary information.
 393   */
 394   /*p->md.stat.ps_recv = 0;*/
 395   /*p->md.stat.ps_drop = 0;*/
 396
 397   *ps = p->md.stat;
 398
 399   return 0;
 400 }
 401
 402 /*
 403  * Get from "/proc/dag" all interfaces listed there; if they're
 404  * already in the list of interfaces we have, that won't add another
 405  * instance, but if they're not, that'll add them.
 406  *
 407  * We don't bother getting any addresses for them.
 408  *
 409  * We also don't fail if we couldn't open "/proc/dag"; we just leave
 410  * the list of interfaces as is.
 411  */
 412 int
 413 dag_platform_finddevs(pcap_if_t **devlistp, char *errbuf)
 414 {
 415   FILE *proc_dag_f;
 416   char linebuf[512];
 417   int linenum;
 418   unsigned char *p;
 419   char name[512];       /* XXX - pick a size */
 420   char *q, *saveq;
 421   struct ifreq ifrflags;
 422   int ret = 0;
 423
 424   /* Quick exit if /proc/dag not readable */
 425   proc_dag_f = fopen("/proc/dag", "r");
 426   if (proc_dag_f == NULL)
 427   {
 428     int i, fd;
 429     char dev[16] = "dagx";
 430
 431     for (i = '0'; ret == 0 && i <= '9'; i++) {
 432       dev[3] = i;
 433       if (pcap_add_if(devlistp, dev, 0, NULL, errbuf) == -1) {
 434         /*
 435          * Failure.
 436          */
 437         ret = -1;
 438       }
 439     }
 440
 441     return (ret);
 442   }
 443
 444   for (linenum = 1;
 445         fgets(linebuf, sizeof linebuf, proc_dag_f) != NULL; linenum++) {
 446
 447     /*
 448      * Skip the first two lines - they're headers.
 449      */
 450     if (linenum <= 2)
 451       continue;
 452
 453     p = &linebuf[0];
 454
 455     if (*p == '\0' || *p == '\n' || *p != 'D')
 456       continue;  /* not a Dag line */
 457
 458     /*
 459      * Get the interface name.
 460      */
 461     q = &name[0];
 462     while (*p != '\0' && *p != ':') {
 463       if (*p != ' ')
 464         *q++ = tolower(*p++);
 465       else
 466         p++;
 467     }
 468     *q = '\0';
 469
 470     /*
 471      * Add an entry for this interface, with no addresses.
 472      */
 473     p[strlen(p) - 1] = '\0'; /* get rid of \n */
 474     if (pcap_add_if(devlistp, name, 0, strdup(p + 2), errbuf) == -1) {
 475       /*
 476        * Failure.
 477        */
 478       ret = -1;
 479       break;
 480     }
 481   }
 482   if (ret != -1) {
 483     /*
 484      * Well, we didn't fail for any other reason; did we
 485      * fail due to an error reading the file?
 486      */
 487     if (ferror(proc_dag_f)) {
 488       (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 489           "Error reading /proc/dag: %s",
 490           pcap_strerror(errno));
 491       ret = -1;
 492     }
 493   }
 494
 495   (void)fclose(proc_dag_f);
 496   return (ret);
 497 }
 498
 499 /*
 500  * Installs the gven bpf filter program in the given pcap structure.  There is
 501  * no attempt to store the filter in kernel memory as that is not supported
 502  * with DAG cards.
 503  */
 504 int dag_setfilter(pcap_t *p, struct bpf_program *fp) {
 505   if (!p)
 506     return -1;
 507   if (!fp) {
 508     strncpy(p->errbuf, "setfilter: No filter specified",
 509             sizeof(p->errbuf));
 510     return -1;
 511   }
 512
 513   /* Make our private copy of the filter */
 514
 515   if (install_bpf_program(p, fp) < 0) {
 516     snprintf(p->errbuf, sizeof(p->errbuf),
 517              "malloc: %s", pcap_strerror(errno));
 518     return -1;
 519   }
 520
 521   p->md.use_bpf = 0;
 522
 523   return (0);
 524 }
 525
 526 int
 527 dag_set_datalink_platform(pcap_t *p, int dlt)
 528 {
 529         return (0);
 530 }