/*
   * pcap-septel.c: Packet capture interface for Intel/Septel card.
   *
   * The functionality of this code attempts to mimic that of pcap-linux as much
   * as possible.  This code is compiled in several different ways depending on
   * whether SEPTEL_ONLY and HAVE_SEPTEL_API are defined.  If HAVE_SEPTEL_API is
   * not defined it should not get compiled in, otherwise if SEPTEL_ONLY is
   * defined then the 'septel_' function calls are renamed to 'pcap_'
   * equivalents.  If SEPTEL_ONLY is not defined then nothing is altered - the
   * septel_ functions will be called as required from their
   * pcap-linux/equivalents.
   *
   * Authors: Gilbert HOYEK (gil_hoyek@hotmail.com), Elias M. KHOURY
   * (+961 3 485243)
   */
  
  #ifdef HAVE_CONFIG_H
  #include <config.h>
  #endif
  
  #include <sys/param.h>
  
  #include <stdlib.h>
  #include <string.h>
  #include <errno.h>
  
  #include "pcap-int.h"
  
  #include <ctype.h>
  #include <netinet/in.h>
  #include <sys/mman.h>
  #include <sys/socket.h>
  #include <sys/types.h>
  #include <unistd.h>
  
  #include <msg.h>
  #include <ss7_inc.h>
  #include <sysgct.h>
  #include <pack.h>
  #include <system.h>
  
  #include "pcap-septel.h"
  
  static int septel_setfilter(pcap_t *p, struct bpf_program *fp);
  static int septel_stats(pcap_t *p, struct pcap_stat *ps);
  static int septel_getnonblock(pcap_t *p);
  static int septel_setnonblock(pcap_t *p, int nonblock);
  
  /*
   * Private data for capturing on Septel devices.
   */
  struct pcap_septel {
  	struct pcap_stat stat;
  }
  
  /*
   *  Read at most max_packets from the capture queue and call the callback
   *  for each of them. Returns the number of packets handled, -1 if an
   *  error occured, or -2 if we were told to break out of the loop.
   */
  static int septel_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) {
  
    struct pcap_septel *ps = p->priv;
    HDR *h;
    MSG *m;
    int processed = 0 ;
    int t = 0 ;
  
    /* identifier for the message queue of the module(upe) from which we are capturing
     * packets.These IDs are defined in system.txt . By default it is set to 0x2d
     * so change it to 0xdd for technical reason and therefore the module id for upe becomes:
     * LOCAL        0xdd           * upe - Example user part task */
    unsigned int id = 0xdd;
  
    /* process the packets */
    do  {
  
      unsigned short packet_len = 0;
      int caplen = 0;
      int counter = 0;
      struct pcap_pkthdr   pcap_header;
      u_char *dp ;
  
      /*
       * Has "pcap_breakloop()" been called?
       */
  loop:
      if (p->break_loop) {
        /*
         * Yes - clear the flag that indicates that
         * it has, and return -2 to indicate that
         * we were told to break out of the loop.
         */
        p->break_loop = 0;
        return -2;
      }
  
      /*repeat until a packet is read
       *a NULL message means :
       * when no packet is in queue or all packets in queue already read */
      do  {
        /* receive packet in non-blocking mode
         * GCT_grab is defined in the septel library software */
        h = GCT_grab(id);
  
        m = (MSG*)h;
        /* a couter is added here to avoid an infinite loop
         * that will cause our capture program GUI to freeze while waiting
         * for a packet*/
        counter++ ;
  
      }
      while  ((m == NULL)&& (counter< 100)) ;
  
      if (m != NULL) {
  
        t = h->type ;
  
        /* catch only messages with type = 0xcf00 or 0x8f01 corrsponding to ss7 messages*/
        /* XXX = why not use API_MSG_TX_REQ for 0xcf00 and API_MSG_RX_IND
         * for 0x8f01? */
        if ((t != 0xcf00) && (t != 0x8f01)) {
          relm(h);
          goto loop ;
        }
  
        /* XXX - is API_MSG_RX_IND for an MTP2 or MTP3 message? */
        dp = get_param(m);/* get pointer to MSG parameter area (m->param) */
        packet_len = m->len;
        caplen =  p->snapshot ;
  
  
        if (caplen > packet_len) {
  
          caplen = packet_len;
        }
        /* Run the packet filter if there is one. */
        if ((p->fcode.bf_insns == NULL) || bpf_filter(p->fcode.bf_insns, dp, packet_len, caplen)) {
  
  
          /*  get a time stamp , consisting of :
           *
           *  pcap_header.ts.tv_sec:
           *  ----------------------
           *   a UNIX format time-in-seconds when he packet was captured,
           *   i.e. the number of seconds since Epoch time (January 1,1970, 00:00:00 GMT)
           *
           *  pcap_header.ts.tv_usec :
           *  ------------------------
           *   the number of microseconds since that second
           *   when the packet was captured
           */
  
          (void)gettimeofday(&pcap_header.ts, NULL);
  
          /* Fill in our own header data */
          pcap_header.caplen = caplen;
          pcap_header.len = packet_len;
  
          /* Count the packet. */
          ps->stat.ps_recv++;
  
          /* Call the user supplied callback function */
          callback(user, &pcap_header, dp);
  
          processed++ ;
  
        }
        /* after being processed the packet must be
         *released in order to receive another one */
        relm(h);
      }else
        processed++;
  
    }
    while (processed < cnt) ;
  
    return processed ;
  }
  
  
  static int
  septel_inject(pcap_t *handle, const void *buf _U_, size_t size _U_)
  {
    strlcpy(handle->errbuf, "Sending packets isn't supported on Septel cards",
            PCAP_ERRBUF_SIZE);
    return (-1);
  }
  
  /*
   *  Activate a handle for a live capture from the given Septel device.  Always pass a NULL device
   *  The promisc flag is ignored because Septel cards have built-in tracing.
   *  The timeout is also ignored as it is not supported in hardware.
   *
   *  See also pcap(3).
   */
  static pcap_t *septel_activate(pcap_t* handle) {
    /* Initialize some components of the pcap structure. */
    handle->linktype = DLT_MTP2;
  
    /*
     * Turn a negative snapshot value (invalid), a snapshot value of
     * 0 (unspecified), or a value bigger than the normal maximum
     * value, into the maximum allowed value.
     *
     * If some application really *needs* a bigger snapshot
     * length, we should just increase MAXIMUM_SNAPLEN.
     */
    if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
      handle->snapshot = MAXIMUM_SNAPLEN;
  
    handle->bufsize = 0;
  
    /*
     * "select()" and "poll()" don't work on Septel queues
     */
    handle->selectable_fd = -1;
  
    handle->read_op = septel_read;
    handle->inject_op = septel_inject;
    handle->setfilter_op = septel_setfilter;
    handle->set_datalink_op = NULL; /* can't change data link type */
    handle->getnonblock_op = septel_getnonblock;
    handle->setnonblock_op = septel_setnonblock;
    handle->stats_op = septel_stats;
  
    return 0;
  }
  
  pcap_t *septel_create(const char *device, char *ebuf, int *is_ours) {
  	const char *cp;
  	pcap_t *p;
  
  	/* Does this look like the Septel device? */
  	cp = strrchr(device, '/');
  	if (cp == NULL)
  		cp = device;
  	if (strcmp(cp, "septel") != 0) {
  		/* Nope, it's not "septel" */
  		*is_ours = 0;
  		return NULL;
  	}
  
  	/* OK, it's probably ours. */
  	*is_ours = 1;
  
  	p = pcap_create_common(ebuf, sizeof (struct pcap_septel));
  	if (p == NULL)
  		return NULL;
  
  	p->activate_op = septel_activate;
  	/*
  	 * Set these up front, so that, even if our client tries
  	 * to set non-blocking mode before we're activated, or
  	 * query the state of non-blocking mode, they get an error,
  	 * rather than having the non-blocking mode option set
  	 * for use later.
  	 */
  	p->getnonblock_op = septel_getnonblock;
  	p->setnonblock_op = septel_setnonblock;
  	return p;
  }
  
  static int septel_stats(pcap_t *p, struct pcap_stat *ps) {
    struct pcap_septel *handlep = p->priv;
    /*handlep->stat.ps_recv = 0;*/
    /*handlep->stat.ps_drop = 0;*/
  
    *ps = handlep->stat;
  
    return 0;
  }
  
  
  int
  septel_findalldevs(pcap_if_list_t *devlistp, char *errbuf)
  {
    /*
     * XXX - do the notions of "up", "running", or "connected" apply here?
     */
    if (add_dev(devlistp,"septel",0,"Intel/Septel device",errbuf) == NULL)
      return -1;
    return 0;
  }
  
  
  /*
   * Installs the given bpf filter program in the given pcap structure.  There is
   * no attempt to store the filter in kernel memory as that is not supported
   * with Septel cards.
   */
  static int septel_setfilter(pcap_t *p, struct bpf_program *fp) {
    if (!p)
      return -1;
    if (!fp) {
      strncpy(p->errbuf, "setfilter: No filter specified",
  	    sizeof(p->errbuf));
      return -1;
    }
  
    /* Make our private copy of the filter */
  
    if (install_bpf_program(p, fp) < 0)
      return -1;
  
    return (0);
  }
  
  /*
   * We don't support non-blocking mode.  I'm not sure what we'd
   * do to support it and, given that we don't support select()/
   * poll()/epoll_wait()/kevent() etc., it probably doesn't
   * matter.
   */
  static int
  septel_getnonblock(pcap_t *p)
  {
    fprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Non-blocking mode not supported on Septel devices");
    return (-1);
  }
  
  static int
  septel_setnonblock(pcap_t *p, int nonblock _U_)
  {
    fprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Non-blocking mode not supported on Septel devices");
    return (-1);
  }
  
  #ifdef SEPTEL_ONLY
  /*
   * This libpcap build supports only Septel cards, not regular network
   * interfaces.
   */
  
  /*
   * There are no regular interfaces, just Septel interfaces.
   */
  int
  pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
  {
    return (0);
  }
  
  /*
   * Attempts to open a regular interface fail.
   */
  pcap_t *
  pcap_create_interface(const char *device, char *errbuf)
  {
    pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
                  "This version of libpcap only supports Septel cards");
    return (NULL);
  }
  
  /*
   * Libpcap version string.
   */
  const char *
  pcap_lib_version(void)
  {
    return (PCAP_VERSION_STRING " (Septel-only)");
  }
  #endif