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

   1 /*
   2  * Copyright (c) 2002 - 2005 NetGroup, Politecnico di Torino (Italy)
   3  * Copyright (c) 2005 - 2008 CACE Technologies, Davis (California)
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  * notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  * notice, this list of conditions and the following disclaimer in the
  14  * documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the Politecnico di Torino, CACE Technologies
  16  * nor the names of its contributors may be used to endorse or promote
  17  * products derived from this software without specific prior written
  18  * permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 #include "ftmacros.h"
  39
  40 /*
  41  * sockutils.h may include <crtdbg.h> on Windows, and pcap-int.h will
  42  * include portability.h, and portability.h, on Windows, expects that
  43  * <crtdbg.h> has already been included, so include sockutils.h first.
  44  */
  45 #include "sockutils.h"
  46 #include "pcap-int.h"   // for the details of the pcap_t structure
  47 #include "pcap-rpcap.h"
  48 #include "rpcap-protocol.h"
  49 #include <errno.h>              // for the errno variable
  50 #include <stdlib.h>             // for malloc(), free(), ...
  51 #include <string.h>             // for strstr, etc
  52
  53 #ifndef _WIN32
  54 #include <dirent.h>             // for readdir
  55 #endif
  56
  57 /* String identifier to be used in the pcap_findalldevs_ex() */
  58 #define PCAP_TEXT_SOURCE_FILE "File"
  59 #define PCAP_TEXT_SOURCE_FILE_LEN (sizeof PCAP_TEXT_SOURCE_FILE - 1)
  60 /* String identifier to be used in the pcap_findalldevs_ex() */
  61 #define PCAP_TEXT_SOURCE_ADAPTER "Network adapter"
  62 #define PCAP_TEXT_SOURCE_ADAPTER_LEN (sizeof "Network adapter" - 1)
  63
  64 /* String identifier to be used in the pcap_findalldevs_ex() */
  65 #define PCAP_TEXT_SOURCE_ON_LOCAL_HOST "on local host"
  66 #define PCAP_TEXT_SOURCE_ON_LOCAL_HOST_LEN (sizeof PCAP_TEXT_SOURCE_ON_LOCAL_HOST + 1)
  67
  68 /****************************************************
  69  *                                                  *
  70  * Function bodies                                  *
  71  *                                                  *
  72  ****************************************************/
  73
  74 int pcap_findalldevs_ex(const char *source, struct pcap_rmtauth *auth, pcap_if_t **alldevs, char *errbuf)
  75 {
  76         int type;
  77         char name[PCAP_BUF_SIZE], path[PCAP_BUF_SIZE], filename[PCAP_BUF_SIZE];
  78         size_t pathlen;
  79         size_t stringlen;
  80         pcap_t *fp;
  81         char tmpstring[PCAP_BUF_SIZE + 1];              /* Needed to convert names and descriptions from 'old' syntax to the 'new' one */
  82         pcap_if_t *lastdev;     /* Last device in the pcap_if_t list */
  83         pcap_if_t *dev;         /* Device we're adding to the pcap_if_t list */
  84
  85         /* List starts out empty. */
  86         (*alldevs) = NULL;
  87         lastdev = NULL;
  88
  89         if (strlen(source) > PCAP_BUF_SIZE)
  90         {
  91                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The source string is too long. Cannot handle it correctly.");
  92                 return -1;
  93         }
  94
  95         /*
  96          * Determine the type of the source (file, local, remote)
  97          * There are some differences if pcap_findalldevs_ex() is called to list files and remote adapters.
  98          * In the first case, the name of the directory we have to look into must be present (therefore
  99          * the 'name' parameter of the pcap_parsesrcstr() is present).
 100          * In the second case, the name of the adapter is not required (we need just the host). So, we have
 101          * to use a first time this function to get the source type, and a second time to get the appropriate
 102          * info, which depends on the source type.
 103          */
 104         if (pcap_parsesrcstr(source, &type, NULL, NULL, NULL, errbuf) == -1)
 105                 return -1;
 106
 107         switch (type)
 108         {
 109         case PCAP_SRC_IFLOCAL:
 110                 if (pcap_parsesrcstr(source, &type, NULL, NULL, NULL, errbuf) == -1)
 111                         return -1;
 112
 113                 /* Initialize temporary string */
 114                 tmpstring[PCAP_BUF_SIZE] = 0;
 115
 116                 /* The user wants to retrieve adapters from a local host */
 117                 if (pcap_findalldevs(alldevs, errbuf) == -1)
 118                         return -1;
 119
 120                 if (*alldevs == NULL)
 121                 {
 122                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 123                                 "No interfaces found! Make sure libpcap/WinPcap is properly installed"
 124                                 " on the local machine.");
 125                         return -1;
 126                 }
 127
 128                 /* Scan all the interfaces and modify name and description */
 129                 /* This is a trick in order to avoid the re-implementation of the pcap_findalldevs here */
 130                 dev = *alldevs;
 131                 while (dev)
 132                 {
 133                         char *localdesc, *desc;
 134
 135                         /* Create the new device identifier */
 136                         if (pcap_createsrcstr(tmpstring, PCAP_SRC_IFLOCAL, NULL, NULL, dev->name, errbuf) == -1)
 137                                 return -1;
 138
 139                         /* Delete the old pointer */
 140                         free(dev->name);
 141
 142                         /* Make a copy of the new device identifier */
 143                         dev->name = strdup(tmpstring);
 144                         if (dev->name == NULL)
 145                         {
 146                                 pcap_fmt_errmsg_for_errno(errbuf,
 147                                     PCAP_ERRBUF_SIZE, errno,
 148                                     "malloc() failed");
 149                                 pcap_freealldevs(*alldevs);
 150                                 return -1;
 151                         }
 152
 153                         /*
 154                          * Create the description.
 155                          */
 156                         if ((dev->description == NULL) || (dev->description[0] == 0))
 157                                 localdesc = dev->name;
 158                         else
 159                                 localdesc = dev->description;
 160                         if (pcap_asprintf(&desc, "%s '%s' %s",
 161                             PCAP_TEXT_SOURCE_ADAPTER, localdesc,
 162                             PCAP_TEXT_SOURCE_ON_LOCAL_HOST) == -1)
 163                         {
 164                                 pcap_fmt_errmsg_for_errno(errbuf,
 165                                     PCAP_ERRBUF_SIZE, errno,
 166                                     "malloc() failed");
 167                                 pcap_freealldevs(*alldevs);
 168                                 return -1;
 169                         }
 170
 171                         /* Now overwrite the description */
 172                         free(dev->description);
 173                         dev->description = desc;
 174
 175                         dev = dev->next;
 176                 }
 177
 178                 return 0;
 179
 180         case PCAP_SRC_FILE:
 181         {
 182 #ifdef _WIN32
 183                 WIN32_FIND_DATA filedata;
 184                 HANDLE filehandle;
 185 #else
 186                 struct dirent *filedata;
 187                 DIR *unixdir;
 188 #endif
 189
 190                 if (pcap_parsesrcstr(source, &type, NULL, NULL, name, errbuf) == -1)
 191                         return -1;
 192
 193                 /* Check that the filename is correct */
 194                 stringlen = strlen(name);
 195
 196                 /* The directory must end with '\' in Win32 and '/' in UNIX */
 197 #ifdef _WIN32
 198 #define ENDING_CHAR '\\'
 199 #else
 200 #define ENDING_CHAR '/'
 201 #endif
 202
 203                 if (name[stringlen - 1] != ENDING_CHAR)
 204                 {
 205                         name[stringlen] = ENDING_CHAR;
 206                         name[stringlen + 1] = 0;
 207
 208                         stringlen++;
 209                 }
 210
 211                 /* Save the path for future reference */
 212                 pcap_snprintf(path, sizeof(path), "%s", name);
 213                 pathlen = strlen(path);
 214
 215 #ifdef _WIN32
 216                 /* To perform directory listing, Win32 must have an 'asterisk' as ending char */
 217                 if (name[stringlen - 1] != '*')
 218                 {
 219                         name[stringlen] = '*';
 220                         name[stringlen + 1] = 0;
 221                 }
 222
 223                 filehandle = FindFirstFile(name, &filedata);
 224
 225                 if (filehandle == INVALID_HANDLE_VALUE)
 226                 {
 227                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Error when listing files: does folder '%s' exist?", path);
 228                         return -1;
 229                 }
 230
 231 #else
 232                 /* opening the folder */
 233                 unixdir= opendir(path);
 234
 235                 /* get the first file into it */
 236                 filedata= readdir(unixdir);
 237
 238                 if (filedata == NULL)
 239                 {
 240                         pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Error when listing files: does folder '%s' exist?", path);
 241                         return -1;
 242                 }
 243 #endif
 244
 245                 /* Add all files we find to the list. */
 246                 do
 247                 {
 248 #ifdef _WIN32
 249                         /* Skip the file if the pathname won't fit in the buffer */
 250                         if (pathlen + strlen(filedata.cFileName) >= sizeof(filename))
 251                                 continue;
 252                         pcap_snprintf(filename, sizeof(filename), "%s%s", path, filedata.cFileName);
 253 #else
 254                         if (pathlen + strlen(filedata->d_name) >= sizeof(filename))
 255                                 continue;
 256                         pcap_snprintf(filename, sizeof(filename), "%s%s", path, filedata->d_name);
 257 #endif
 258
 259                         fp = pcap_open_offline(filename, errbuf);
 260
 261                         if (fp)
 262                         {
 263                                 /* allocate the main structure */
 264                                 dev = (pcap_if_t *)malloc(sizeof(pcap_if_t));
 265                                 if (dev == NULL)
 266                                 {
 267                                         pcap_fmt_errmsg_for_errno(errbuf,
 268                                             PCAP_ERRBUF_SIZE, errno,
 269                                             "malloc() failed");
 270                                         pcap_freealldevs(*alldevs);
 271                                         return -1;
 272                                 }
 273
 274                                 /* Initialize the structure to 'zero' */
 275                                 memset(dev, 0, sizeof(pcap_if_t));
 276
 277                                 /* Append it to the list. */
 278                                 if (lastdev == NULL)
 279                                 {
 280                                         /*
 281                                          * List is empty, so it's also
 282                                          * the first device.
 283                                          */
 284                                         *alldevs = dev;
 285                                 }
 286                                 else
 287                                 {
 288                                         /*
 289                                          * Append after the last device.
 290                                          */
 291                                         lastdev->next = dev;
 292                                 }
 293                                 /* It's now the last device. */
 294                                 lastdev = dev;
 295
 296                                 /* Create the new source identifier */
 297                                 if (pcap_createsrcstr(tmpstring, PCAP_SRC_FILE, NULL, NULL, filename, errbuf) == -1)
 298                                 {
 299                                         pcap_freealldevs(*alldevs);
 300                                         return -1;
 301                                 }
 302
 303                                 dev->name = strdup(tmpstring);
 304                                 if (dev->name == NULL)
 305                                 {
 306                                         pcap_fmt_errmsg_for_errno(errbuf,
 307                                             PCAP_ERRBUF_SIZE, errno,
 308                                             "malloc() failed");
 309                                         pcap_freealldevs(*alldevs);
 310                                         return -1;
 311                                 }
 312
 313                                 /*
 314                                  * Create the description.
 315                                  */
 316                                 if (pcap_asprintf(&dev->description,
 317                                     "%s '%s' %s", PCAP_TEXT_SOURCE_FILE,
 318                                     filename, PCAP_TEXT_SOURCE_ON_LOCAL_HOST) == -1)
 319                                 {
 320                                         pcap_fmt_errmsg_for_errno(errbuf,
 321                                             PCAP_ERRBUF_SIZE, errno,
 322                                             "malloc() failed");
 323                                         pcap_freealldevs(*alldevs);
 324                                         return -1;
 325                                 }
 326
 327                                 pcap_close(fp);
 328                         }
 329                 }
 330 #ifdef _WIN32
 331                 while (FindNextFile(filehandle, &filedata) != 0);
 332 #else
 333                 while ( (filedata= readdir(unixdir)) != NULL);
 334 #endif
 335
 336
 337 #ifdef _WIN32
 338                 /* Close the search handle. */
 339                 FindClose(filehandle);
 340 #endif
 341
 342                 return 0;
 343         }
 344
 345         case PCAP_SRC_IFREMOTE:
 346                 return pcap_findalldevs_ex_remote(source, auth, alldevs, errbuf);
 347
 348         default:
 349                 pcap_strlcpy(errbuf, "Source type not supported", PCAP_ERRBUF_SIZE);
 350                 return -1;
 351         }
 352 }
 353
 354 pcap_t *pcap_open(const char *source, int snaplen, int flags, int read_timeout, struct pcap_rmtauth *auth, char *errbuf)
 355 {
 356         char name[PCAP_BUF_SIZE];
 357         int type;
 358         pcap_t *fp;
 359         int status;
 360
 361         if (strlen(source) > PCAP_BUF_SIZE)
 362         {
 363                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The source string is too long. Cannot handle it correctly.");
 364                 return NULL;
 365         }
 366
 367         /*
 368          * Determine the type of the source (file, local, remote) and,
 369          * if it's file or local, the name of the file or capture device.
 370          */
 371         if (pcap_parsesrcstr(source, &type, NULL, NULL, name, errbuf) == -1)
 372                 return NULL;
 373
 374         switch (type)
 375         {
 376         case PCAP_SRC_FILE:
 377                 return pcap_open_offline(name, errbuf);
 378
 379         case PCAP_SRC_IFLOCAL:
 380                 fp = pcap_create(name, errbuf);
 381                 break;
 382
 383         case PCAP_SRC_IFREMOTE:
 384                 /*
 385                  * Although we already have host, port and iface, we prefer
 386                  * to pass only 'source' to pcap_open_rpcap(), so that it
 387                  * has to call pcap_parsesrcstr() again.
 388                  * This is less optimized, but much clearer.
 389                  */
 390                 return pcap_open_rpcap(source, snaplen, flags, read_timeout, auth, errbuf);
 391
 392         default:
 393                 pcap_strlcpy(errbuf, "Source type not supported", PCAP_ERRBUF_SIZE);
 394                 return NULL;
 395         }
 396
 397         if (fp == NULL)
 398                 return (NULL);
 399         status = pcap_set_snaplen(fp, snaplen);
 400         if (status < 0)
 401                 goto fail;
 402         if (flags & PCAP_OPENFLAG_PROMISCUOUS)
 403         {
 404                 status = pcap_set_promisc(fp, 1);
 405                 if (status < 0)
 406                         goto fail;
 407         }
 408         if (flags & PCAP_OPENFLAG_MAX_RESPONSIVENESS)
 409         {
 410                 status = pcap_set_immediate_mode(fp, 1);
 411                 if (status < 0)
 412                         goto fail;
 413         }
 414 #ifdef _WIN32
 415         /*
 416          * This flag is supported on Windows only.
 417          * XXX - is there a way to support it with
 418          * the capture mechanisms on UN*X?  It's not
 419          * exactly a "set direction" operation; I
 420          * think it means "do not capture packets
 421          * injected with pcap_sendpacket() or
 422          * pcap_inject()".
 423          */
 424         /* disable loopback capture if requested */
 425         if (flags & PCAP_OPENFLAG_NOCAPTURE_LOCAL)
 426                 fp->opt.nocapture_local = 1;
 427 #endif /* _WIN32 */
 428         status = pcap_set_timeout(fp, read_timeout);
 429         if (status < 0)
 430                 goto fail;
 431         status = pcap_activate(fp);
 432         if (status < 0)
 433                 goto fail;
 434         return fp;
 435
 436 fail:
 437         if (status == PCAP_ERROR)
 438                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
 439                     name, fp->errbuf);
 440         else if (status == PCAP_ERROR_NO_SUCH_DEVICE ||
 441             status == PCAP_ERROR_PERM_DENIED ||
 442             status == PCAP_ERROR_PROMISC_PERM_DENIED)
 443                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s (%s)",
 444                     name, pcap_statustostr(status), fp->errbuf);
 445         else
 446                 pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
 447                     name, pcap_statustostr(status));
 448         pcap_close(fp);
 449         return NULL;
 450 }
 451
 452 struct pcap_samp *pcap_setsampling(pcap_t *p)
 453 {
 454         return &p->rmt_samp;
 455 }