/* $Id: snoop.c 767 2004-10-06 12:48:49Z aturner $ */

/*
 * Copyright (c) 2001-2004 Aaron Turner, Matt Bing.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright owners nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <sys/types.h>

#include "capinfo.h"
#include "snoop.h"
#include "err.h"

char *snoop_links[] = {
    "ethernet",
    "unknown",
    "token ring",
    "unknown",
    "ethernet",
    "HDLC",
    "character synchronous",
    "IBM channel to channel",
    "FDDI bitswapped",
    "unknown",
    "frame relay LAPD",
    "frame relay",
    "character asynchronous (PPP/SLIP)",
    "X.25",
    "loopback",
    "unknown",
    "fibre channel",
    "ATM",
    "ATM",
    "X.25 LAPB",
    "ISDN",
    "HIPPI",
    "100VG-AnyLAN ethernet",
    "100VG-AnyLAN token ring",
    "ethernet",
    "100Base-T ethernet",
    NULL
};

#define LINKSIZE (sizeof(snoop_links) / sizeof(snoop_links[0]) - 1)

struct snoop_hdr shdr;

int
is_snoop(int fd)
{
    char *snoop_magic = SNOOP_MAGIC;

    if (lseek(fd, SEEK_SET, 0) != 0) {
        err(1, "Unable to seek to start of file");
    }

    if (read(fd, &shdr, sizeof(shdr)) != sizeof(shdr))
        return 0;

    if (memcmp(&shdr.magic, snoop_magic, sizeof(shdr.magic)) == 0) {
        shdr.version = ntohl(shdr.version);
        shdr.network = ntohl(shdr.network);

        /* Dunno about snoop format history, but 2 definately works */
        if (shdr.version != 2)
            return 0;

        return 1;
    }

    return 0;
}

int
get_next_snoop(int fd, struct packet *pkt)
{
    struct snoop_rec rec;
    int pad;

    if (read(fd, &rec, sizeof(rec)) != sizeof(rec))
        return 0;

    pkt->len = ntohl(rec.incl_len);
    pkt->actual_len = ntohl(rec.orig_len);
    pkt->ts.tv_sec = ntohl(rec.ts_sec);
    pkt->ts.tv_usec = ntohl(rec.ts_usec);

    if (read(fd, &pkt->data, pkt->len) != pkt->len)
        return 0;

    /* Skip padding */
    pad = ntohl(rec.rec_len) - (sizeof(rec) + pkt->len);
    if (lseek(fd, pad, SEEK_CUR) == -1)
        return 0;

    return pkt->len;
}

void
stat_snoop(int fd, struct snoop_info *p)
{
    struct packet pkt;

    p->version = shdr.version;

    if (shdr.network > LINKSIZE)
        p->linktype = "unknown linktype";
    else
        p->linktype = snoop_links[shdr.network];

    p->bytes = p->trunc = 0;
    for (p->cnt = 0; get_next_snoop(fd, &pkt); p->cnt++) {
        /* grab time of the first packet */
        if (p->cnt == 0)
            TIMEVAL_TO_TIMESPEC(&pkt.ts, &p->start_tm);

        /* count truncated packets */
        p->bytes += pkt.len;
        if (pkt.actual_len > pkt.len)
            p->trunc++;
    }

    /* grab time of the last packet */
    TIMEVAL_TO_TIMESPEC(&pkt.ts, &p->finish_tm);
}