/* packet-ipsec.c
 * Routines for IPsec packet disassembly 
 *
 * $Id: packet-ipsec.c,v 1.1 1999/03/29 02:21:34 gram Exp $
 *
 * Ethereal - Network traffic analyzer
 * By Gerald Combs <gerald@zing.org>
 * Copyright 1998 Gerald Combs
 *
 * 
 * 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

#include <stdio.h>

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

#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif

#include <glib.h>
#include "packet.h"
#include "resolv.h"

struct newah {
	guint8	ah_nxt;		/* Next Header */
	guint8	ah_len;		/* Length of data + 1, in 32bit */
	guint16	ah_reserve;	/* Reserved for future use */
	guint32	ah_spi;		/* Security parameter index */
	guint32	ah_seq;		/* Sequence number field */
	/* variable size, 32bit bound*/	/* Authentication data */
};

struct newesp {
	guint32	esp_spi;	/* ESP */
	guint32	esp_seq;	/* Sequence number */
	/*variable size*/		/* (IV and) Payload data */
	/*variable size*/		/* padding */
	/*8bit*/			/* pad size */
	/*8bit*/			/* next header */
	/*8bit*/			/* next header */
	/*variable size, 32bit bound*/	/* Authentication data */
};

#ifndef offsetof
#define	offsetof(type, member)	((size_t)(&((type *)0)->member))
#endif

int
dissect_ah(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
{
    proto_tree *ah_tree;
	proto_item *ti;
    struct newah ah;
    int advance;

    memcpy(&ah, (void *) &pd[offset], sizeof(ah)); 
    advance = sizeof(ah) + ((ah.ah_len - 1) << 2);

    if (check_col(fd, COL_PROTOCOL))
	col_add_str(fd, COL_PROTOCOL, "AH");
    if (check_col(fd, COL_INFO)) {
	col_add_fstr(fd, COL_INFO, "AH (SPI=%08x)",
	    (guint32)ntohl(ah.ah_spi));
    }

    if (tree) {
	/* !!! specify length */
	ti = proto_tree_add_item(tree, offset, advance, "Authentication Header");
	ah_tree = proto_tree_new();
	proto_item_add_subtree(ti, ah_tree, ETT_AH);

	proto_tree_add_item(ah_tree, offset + offsetof(struct newah, ah_nxt), 1,
	    "Next Header: %d", ah.ah_nxt);
	proto_tree_add_item(ah_tree, offset + offsetof(struct newah, ah_len), 1,
	    "Length: %d", ah.ah_len << 2);
	proto_tree_add_item(ah_tree, offset + offsetof(struct newah, ah_spi), 4,
	    "SPI: %08x", (guint32)ntohl(ah.ah_spi));
	proto_tree_add_item(ah_tree, offset + offsetof(struct newah, ah_seq), 4,
	    "Sequence?: %08x", (guint32)ntohl(ah.ah_seq));
	proto_tree_add_item(ah_tree, offset + sizeof(ah), (ah.ah_len - 1) << 2,
	    "ICV");
    }

    /* start of the new header (could be a extension header) */
    return advance;
}

void
dissect_esp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
{
	proto_tree *esp_tree;
    proto_item *ti;
    struct newesp esp;

    memcpy(&esp, (void *) &pd[offset], sizeof(esp)); 

    /*
     * load the top pane info. This should be overwritten by
     * the next protocol in the stack
     */
    if (check_col(fd, COL_PROTOCOL))
	col_add_str(fd, COL_PROTOCOL, "ESP");
    if (check_col(fd, COL_INFO)) {
	col_add_fstr(fd, COL_INFO, "ESP (SPI=%08x)",
	    (guint32)ntohl(esp.esp_spi));
    }

    /*
     * populate a tree in the second pane with the status of the link layer
     * (ie none)
     */
    if(tree) {
	ti = proto_tree_add_item(tree, 0, 0, "Encapsulated Security Payload");
	esp_tree = proto_tree_new();
	proto_item_add_subtree(ti, esp_tree, ETT_ESP);
	proto_tree_add_item(esp_tree, offset + offsetof(struct newesp, esp_spi), 4,
	    "SPI: %08x", (guint32)ntohl(esp.esp_spi));
	proto_tree_add_item(esp_tree, offset + offsetof(struct newesp, esp_seq), 4,
	    "Sequence?: %08x", (guint32)ntohl(esp.esp_seq));
    }
}