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

   1 /*
   2  * pcap-septel.c: Packet capture interface for Intel/Septel 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 SEPTEL_ONLY and HAVE_SEPTEL_API are defined.  If HAVE_SEPTEL_API is
   7  * not defined it should not get compiled in, otherwise if SEPTEL_ONLY is
   8  * defined then the 'septel_' function calls are renamed to 'pcap_'
   9  * equivalents.  If SEPTEL_ONLY is not defined then nothing is altered - the
  10  * septel_ functions will be called as required from their
  11  * pcap-linux/equivalents.
  12  *
  13  * Authors: Gilbert HOYEK (gil_hoyek@hotmail.com), Elias M. KHOURY
  14  * (+961 3 485243)
  15  */
  16
  17 #ifdef HAVE_CONFIG_H
  18 #include "config.h"
  19 #endif
  20
  21 #include <sys/param.h>
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26
  27 #include "pcap-int.h"
  28
  29 #include <ctype.h>
  30 #include <netinet/in.h>
  31 #include <sys/mman.h>
  32 #include <sys/socket.h>
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35
  36 #include <msg.h>
  37 #include <ss7_inc.h>
  38 #include <sysgct.h>
  39 #include <pack.h>
  40 #include <system.h>
  41
  42 #include "pcap-septel.h"
  43
  44 static int septel_setfilter(pcap_t *p, struct bpf_program *fp);
  45 static int septel_stats(pcap_t *p, struct pcap_stat *ps);
  46 static int septel_setnonblock(pcap_t *p, int nonblock);
  47
  48 /*
  49  * Private data for capturing on Septel devices.
  50  */
  51 struct pcap_septel {
  52         struct pcap_stat stat;
  53 }
  54
  55 /*
  56  *  Read at most max_packets from the capture queue and call the callback
  57  *  for each of them. Returns the number of packets handled, -1 if an
  58  *  error occured, or -2 if we were told to break out of the loop.
  59  */
  60 static int septel_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) {
  61
  62   struct pcap_septel *ps = p->priv;
  63   HDR *h;
  64   MSG *m;
  65   int processed = 0 ;
  66   int t = 0 ;
  67
  68   /* identifier for the message queue of the module(upe) from which we are capturing
  69    * packets.These IDs are defined in system.txt . By default it is set to 0x2d
  70    * so change it to 0xdd for technical reason and therefore the module id for upe becomes:
  71    * LOCAL        0xdd           * upe - Example user part task */
  72   unsigned int id = 0xdd;
  73
  74   /* process the packets */
  75   do  {
  76
  77     unsigned short packet_len = 0;
  78     int caplen = 0;
  79     int counter = 0;
  80     struct pcap_pkthdr   pcap_header;
  81     u_char *dp ;
  82
  83     /*
  84      * Has "pcap_breakloop()" been called?
  85      */
  86 loop:
  87     if (p->break_loop) {
  88       /*
  89        * Yes - clear the flag that indicates that
  90        * it has, and return -2 to indicate that
  91        * we were told to break out of the loop.
  92        */
  93       p->break_loop = 0;
  94       return -2;
  95     }
  96
  97     /*repeat until a packet is read
  98      *a NULL message means :
  99      * when no packet is in queue or all packets in queue already read */
 100     do  {
 101       /* receive packet in non-blocking mode
 102        * GCT_grab is defined in the septel library software */
 103       h = GCT_grab(id);
 104
 105       m = (MSG*)h;
 106       /* a couter is added here to avoid an infinite loop
 107        * that will cause our capture program GUI to freeze while waiting
 108        * for a packet*/
 109       counter++ ;
 110
 111     }
 112     while  ((m == NULL)&& (counter< 100)) ;
 113
 114     if (m != NULL) {
 115
 116       t = h->type ;
 117
 118       /* catch only messages with type = 0xcf00 or 0x8f01 corrsponding to ss7 messages*/
 119       /* XXX = why not use API_MSG_TX_REQ for 0xcf00 and API_MSG_RX_IND
 120        * for 0x8f01? */
 121       if ((t != 0xcf00) && (t != 0x8f01)) {
 122         relm(h);
 123         goto loop ;
 124       }
 125
 126       /* XXX - is API_MSG_RX_IND for an MTP2 or MTP3 message? */
 127       dp = get_param(m);/* get pointer to MSG parameter area (m->param) */
 128       packet_len = m->len;
 129       caplen =  p->snapshot ;
 130
 131
 132       if (caplen > packet_len) {
 133
 134         caplen = packet_len;
 135       }
 136       /* Run the packet filter if there is one. */
 137       if ((p->fcode.bf_insns == NULL) || bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen)) {
 138
 139
 140         /*  get a time stamp , consisting of :
 141          *
 142          *  pcap_header.ts.tv_sec:
 143          *  ----------------------
 144          *   a UNIX format time-in-seconds when he packet was captured,
 145          *   i.e. the number of seconds since Epoch time (January 1,1970, 00:00:00 GMT)
 146          *
 147          *  pcap_header.ts.tv_usec :
 148          *  ------------------------
 149          *   the number of microseconds since that second
 150          *   when the packet was captured
 151          */
 152
 153         (void)gettimeofday(&pcap_header.ts, NULL);
 154
 155         /* Fill in our own header data */
 156         pcap_header.caplen = caplen;
 157         pcap_header.len = packet_len;
 158
 159         /* Count the packet. */
 160         ps->stat.ps_recv++;
 161
 162         /* Call the user supplied callback function */
 163         callback(user, &pcap_header, dp);
 164
 165         processed++ ;
 166
 167       }
 168       /* after being processed the packet must be
 169        *released in order to receive another one */
 170       relm(h);
 171     }else
 172       processed++;
 173
 174   }
 175   while (processed < cnt) ;
 176
 177   return processed ;
 178 }
 179
 180
 181 static int
 182 septel_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
 183 {
 184   strlcpy(handle->errbuf, "Sending packets isn't supported on Septel cards",
 185           PCAP_ERRBUF_SIZE);
 186   return (-1);
 187 }
 188
 189 /*
 190  *  Activate a handle for a live capture from the given Septel device.  Always pass a NULL device
 191  *  The promisc flag is ignored because Septel cards have built-in tracing.
 192  *  The timeout is also ignored as it is not supported in hardware.
 193  *
 194  *  See also pcap(3).
 195  */
 196 static pcap_t *septel_activate(pcap_t* handle) {
 197   /* Initialize some components of the pcap structure. */
 198   handle->linktype = DLT_MTP2;
 199
 200   /*
 201    * Turn a negative snapshot value (invalid), a snapshot value of
 202    * 0 (unspecified), or a value bigger than the normal maximum
 203    * value, into the maximum allowed value.
 204    *
 205    * If some application really *needs* a bigger snapshot
 206    * length, we should just increase MAXIMUM_SNAPLEN.
 207    */
 208   if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
 209     handle->snapshot = MAXIMUM_SNAPLEN;
 210
 211   handle->bufsize = 0;
 212
 213   /*
 214    * "select()" and "poll()" don't work on Septel queues
 215    */
 216   handle->selectable_fd = -1;
 217
 218   handle->read_op = septel_read;
 219   handle->inject_op = septel_inject;
 220   handle->setfilter_op = septel_setfilter;
 221   handle->set_datalink_op = NULL; /* can't change data link type */
 222   handle->getnonblock_op = pcap_getnonblock_fd;
 223   handle->setnonblock_op = septel_setnonblock;
 224   handle->stats_op = septel_stats;
 225
 226   return 0;
 227 }
 228
 229 pcap_t *septel_create(const char *device, char *ebuf, int *is_ours) {
 230         const char *cp;
 231         pcap_t *p;
 232
 233         /* Does this look like the Septel device? */
 234         cp = strrchr(device, '/');
 235         if (cp == NULL)
 236                 cp = device;
 237         if (strcmp(cp, "septel") != 0) {
 238                 /* Nope, it's not "septel" */
 239                 *is_ours = 0;
 240                 return NULL;
 241         }
 242
 243         /* OK, it's probably ours. */
 244         *is_ours = 1;
 245
 246         p = pcap_create_common(ebuf, sizeof (struct pcap_septel));
 247         if (p == NULL)
 248                 return NULL;
 249
 250         p->activate_op = septel_activate;
 251         p->setnonblock_op = septel_setnonblock; /* not supported */
 252         return p;
 253 }
 254
 255 static int septel_stats(pcap_t *p, struct pcap_stat *ps) {
 256   struct pcap_septel *handlep = p->priv;
 257   /*handlep->stat.ps_recv = 0;*/
 258   /*handlep->stat.ps_drop = 0;*/
 259
 260   *ps = handlep->stat;
 261
 262   return 0;
 263 }
 264
 265
 266 int
 267 septel_findalldevs(pcap_if_list_t *devlistp, char *errbuf)
 268 {
 269   if (add_dev(devlistp,"septel",0,"Intel/Septel device",errbuf) == NULL)
 270     return -1;
 271   return 0;
 272 }
 273
 274
 275 /*
 276  * Installs the given bpf filter program in the given pcap structure.  There is
 277  * no attempt to store the filter in kernel memory as that is not supported
 278  * with Septel cards.
 279  */
 280 static int septel_setfilter(pcap_t *p, struct bpf_program *fp) {
 281   if (!p)
 282     return -1;
 283   if (!fp) {
 284     strncpy(p->errbuf, "setfilter: No filter specified",
 285             sizeof(p->errbuf));
 286     return -1;
 287   }
 288
 289   /* Make our private copy of the filter */
 290
 291   if (install_bpf_program(p, fp) < 0) {
 292     pcap_snprintf(p->errbuf, sizeof(p->errbuf),
 293              "malloc: %s", pcap_strerror(errno));
 294     return -1;
 295   }
 296
 297   return (0);
 298 }
 299
 300
 301 static int
 302 septel_setnonblock(pcap_t *p, int nonblock)
 303 {
 304   fprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Non-blocking mode not supported on Septel devices");
 305   return (-1);
 306 }
 307
 308 #ifdef SEPTEL_ONLY
 309 /*
 310  * This libpcap build supports only Septel cards, not regular network
 311  * interfaces.
 312  */
 313
 314 /*
 315  * There are no regular interfaces, just Septel interfaces.
 316  */
 317 int
 318 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 319 {
 320   return (0);
 321 }
 322
 323 /*
 324  * Attempts to open a regular interface fail.
 325  */
 326 pcap_t *
 327 pcap_create_interface(const char *device, char *errbuf)
 328 {
 329   pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
 330                 "This version of libpcap only supports Septel cards");
 331   return (NULL);
 332 }
 333
 334 /*
 335  * Platform-specific information.
 336  */
 337 const char *
 338 pcap_platform_lib_version(void)
 339 {
 340         return ("Septel-only");
 341 }
 342 #endif