/*
 *  packet-prism.c
 *	Decode packets with a Prism header
 *
 * Prism II-based wlan devices have a monitoring mode that sticks
 * a proprietary header on each packet with lots of good
 * information.  This file is responsible for decoding that
 * data.
 *
 * By Tim Newsham
 *
 * $Id: packet-prism.c,v 1.6 2002/01/21 07:36:38 guy Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@ethereal.com>
 * Copyright 1998 Gerald Combs
 *
 * Copied from README.developer
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#include <glib.h>

#include <epan/packet.h>
#include "packet-ieee80211.h"
#include "packet-prism.h"

/* protocol */
static int proto_prism = -1;

/* header fields */
static int hf_prism_msgcode = -1;
static int hf_prism_msglen = -1;

/* a 802.11 value */
struct val_80211 {
    unsigned int did;
    unsigned short status, len;
    unsigned int data;
};

/* header attached during prism monitor mode */
struct prism_hdr {
    unsigned int msgcode, msglen;
    char devname[16];
    struct val_80211 hosttime, mactime, channel, rssi, sq, signal, 
        noise, rate, istx, frmlen;
};

#define VALFIELDS(name) \
    static int hf_prism_ ## name ## _data = -1
VALFIELDS(hosttime);
VALFIELDS(mactime);
VALFIELDS(channel);
VALFIELDS(rssi);
VALFIELDS(sq);
VALFIELDS(signal);
VALFIELDS(noise);
VALFIELDS(rate);
VALFIELDS(istx);
VALFIELDS(frmlen);

static gint ett_prism = -1;

static dissector_handle_t ieee80211_handle;

void
capture_prism(const u_char *pd, int offset, int len, packet_counts *ld)
{
    if(!BYTES_ARE_IN_FRAME(offset, len, (int)sizeof(struct prism_hdr))) {
        ld->other ++;
        return;
    }
    offset += sizeof(struct prism_hdr);

    /* 802.11 header follows */
    capture_ieee80211(pd, offset, len, ld);
}

/*
 * yah, I know, macros, ugh, but it makes the code
 * below more readable
 */
#define IFHELP(size, name, var, str) \
        proto_tree_add_uint_format(prism_tree, hf_prism_ ## name, \
            tvb, offset, size, hdr. ## var, str, hdr. ## var);	  \
        offset += (size)
#define INTFIELD(size, name, str)	IFHELP(size, name, name, str)
#define VALFIELD(name, str) \
        proto_tree_add_uint_format(prism_tree, hf_prism_ ## name ## _data, \
            tvb, offset, 12, hdr. ## name ## .data,			   \
            str ": 0x%x (DID 0x%x, Status 0x%x, Length 0x%x)",		   \
            hdr. ## name ## .data, hdr. ## name ## .did,		   \
            hdr. ## name ## .status, hdr. ## name ## .len);		   \
        offset += 12

static void
dissect_prism(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
    struct prism_hdr hdr;
    proto_tree *prism_tree;
    proto_item *ti;
    tvbuff_t *next_tvb;
    int offset;

    if(check_col(pinfo->cinfo, COL_PROTOCOL))
        col_set_str(pinfo->cinfo, COL_PROTOCOL, "Prism");
    if(check_col(pinfo->cinfo, COL_INFO))
        col_clear(pinfo->cinfo, COL_INFO);

    offset = 0;
    tvb_memcpy(tvb, (guint8 *)&hdr, offset, sizeof hdr);

    if(check_col(pinfo->cinfo, COL_INFO))
        col_add_fstr(pinfo->cinfo, COL_INFO, "Device: %.16s  "
                     "Message 0x%x, Length %d", hdr.devname,
                     hdr.msgcode, hdr.msglen);

    if(tree) {
        ti = proto_tree_add_protocol_format(tree, proto_prism, 
            tvb, 0, sizeof hdr, "Prism Monitoring Header");
        prism_tree = proto_item_add_subtree(ti, ett_prism);

        INTFIELD(4, msgcode, "Message Code: %d");
        INTFIELD(4, msglen, "Message Length: %d");
        proto_tree_add_text(prism_tree, tvb, offset, sizeof hdr.devname,
            "Device: %s", hdr.devname);
        offset += sizeof hdr.devname;

        VALFIELD(hosttime, "Host Time");
        VALFIELD(mactime, "MAC Time");
        VALFIELD(channel, "Channel Time");
        VALFIELD(rssi, "RSSI");
        VALFIELD(sq, "SQ");
        VALFIELD(signal, "Signal");
        VALFIELD(noise, "Noise");
        VALFIELD(rate, "Rate");
        VALFIELD(istx, "IsTX");
        VALFIELD(frmlen, "Frame Length");
    }

    /* dissect the 802.11 header next */
    next_tvb = tvb_new_subset(tvb, sizeof hdr, -1, -1);
    call_dissector(ieee80211_handle, next_tvb, pinfo, tree);
}

#define IFHELP2(size, name, var, str) \
        { &hf_prism_ ## name, {					   \
            str, "prism." #var, size, BASE_HEX, NULL, 0x0, "", HFILL } },
#define INTFIELD2(size, name, str)	IFHELP2(size, name, name, str)
#define VALFIELD2(name, str) \
   IFHELP2(FT_UINT32, name ## _data, name ## .data, str ## " Field")

void
proto_register_prism(void)
{
    static hf_register_info hf[] = {
        INTFIELD2(FT_UINT32, msgcode, "Message Code")
        INTFIELD2(FT_UINT32, msglen, "Message Length")
        VALFIELD2(hosttime, "Host Time")
        VALFIELD2(mactime, "MAC Time")
        VALFIELD2(channel, "Channel Time")
        VALFIELD2(rssi, "RSSI")
        VALFIELD2(sq, "SQ")
        VALFIELD2(signal, "Signal")
        VALFIELD2(noise, "Noise")
        VALFIELD2(rate, "Rate")
        VALFIELD2(istx, "IsTX")
        VALFIELD2(frmlen, "Frame Length")
        
    }; 
    static gint *ett[] = {
        &ett_prism
    };

    proto_prism = proto_register_protocol("Prism", "Prism", "prism");
    proto_register_field_array(proto_prism, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
}

void
proto_reg_handoff_prism(void)
{
    dissector_handle_t prism_handle;

    /* handle for 802.11 dissector */
    ieee80211_handle = find_dissector("wlan");

    prism_handle = create_dissector_handle(dissect_prism, proto_prism);
    dissector_add("wtap_encap", WTAP_ENCAP_PRISM_HEADER, prism_handle);
}