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      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 (at) 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, char *errbuf);
     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   handle->bufsize = 0;
    201 
    202   /*
    203    * "select()" and "poll()" don't work on Septel queues
    204    */
    205   handle->selectable_fd = -1;
    206 
    207   handle->read_op = septel_read;
    208   handle->inject_op = septel_inject;
    209   handle->setfilter_op = septel_setfilter;
    210   handle->set_datalink_op = NULL; /* can't change data link type */
    211   handle->getnonblock_op = pcap_getnonblock_fd;
    212   handle->setnonblock_op = septel_setnonblock;
    213   handle->stats_op = septel_stats;
    214 
    215   return 0;
    216 }
    217 
    218 pcap_t *septel_create(const char *device, char *ebuf, int *is_ours) {
    219 	const char *cp;
    220 	pcap_t *p;
    221 
    222 	/* Does this look like the Septel device? */
    223 	cp = strrchr(device, '/');
    224 	if (cp == NULL)
    225 		cp = device;
    226 	if (strcmp(cp, "septel") != 0) {
    227 		/* Nope, it's not "septel" */
    228 		*is_ours = 0;
    229 		return NULL;
    230 	}
    231 
    232 	/* OK, it's probably ours. */
    233 	*is_ours = 1;
    234 
    235 	p = pcap_create_common(device, ebuf, sizeof (struct pcap_septel));
    236 	if (p == NULL)
    237 		return NULL;
    238 
    239 	p->activate_op = septel_activate;
    240 	return p;
    241 }
    242 
    243 static int septel_stats(pcap_t *p, struct pcap_stat *ps) {
    244   struct pcap_septel *handlep = p->priv;
    245   /*handlep->stat.ps_recv = 0;*/
    246   /*handlep->stat.ps_drop = 0;*/
    247 
    248   *ps = handlep->stat;
    249 
    250   return 0;
    251 }
    252 
    253 
    254 int
    255 septel_findalldevs(pcap_if_t **devlistp, char *errbuf)
    256 {
    257   return (pcap_add_if(devlistp,"septel",0,
    258                       "Intel/Septel device",errbuf));
    259 }
    260 
    261 
    262 /*
    263  * Installs the given bpf filter program in the given pcap structure.  There is
    264  * no attempt to store the filter in kernel memory as that is not supported
    265  * with Septel cards.
    266  */
    267 static int septel_setfilter(pcap_t *p, struct bpf_program *fp) {
    268   if (!p)
    269     return -1;
    270   if (!fp) {
    271     strncpy(p->errbuf, "setfilter: No filter specified",
    272 	    sizeof(p->errbuf));
    273     return -1;
    274   }
    275 
    276   /* Make our private copy of the filter */
    277 
    278   if (install_bpf_program(p, fp) < 0) {
    279     snprintf(p->errbuf, sizeof(p->errbuf),
    280 	     "malloc: %s", pcap_strerror(errno));
    281     return -1;
    282   }
    283 
    284   return (0);
    285 }
    286 
    287 
    288 static int
    289 septel_setnonblock(pcap_t *p, int nonblock, char *errbuf)
    290 {
    291   fprintf(errbuf, PCAP_ERRBUF_SIZE, "Non-blocking mode not supported on Septel devices");
    292   return (-1);
    293 }
    294