source: lib/format_pcapfile.c @ 114b8d6

/*
 * This file is part of libtrace
 *
 * Copyright (c) 2004 The University of Waikato, Hamilton, New Zealand.
 * Authors: Daniel Lawson 
 *          Perry Lorier 
 *          
 * All rights reserved.
 *
 * This code has been developed by the University of Waikato WAND 
 * research group. For further information please see http://www.wand.net.nz/
 *
 * libtrace 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.
 *
 * libtrace 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 libtrace; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id$
 *
 */

#include "common.h"
#include "config.h"
#include "libtrace.h"
#include "libtrace_int.h"
#include "format_helper.h"

#include <sys/stat.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#define DATA(x) ((struct pcapfile_format_data_t*)((x)->format_data))

struct pcapfile_format_data_t {
        libtrace_io_t *file;
        struct pcapfile_header_t {
                uint32_t magic_number;   /* magic number */
                uint16_t version_major;  /* major version number */
                uint16_t version_minor;  /* minor version number */
                int32_t  thiszone;       /* GMT to local correction */
                uint32_t sigfigs;        /* timestamp accuracy */
                uint32_t snaplen;        /* aka "wirelen" */
                uint32_t network;        /* data link type */
        } header;
};

static int pcapfile_init_input(struct libtrace_t *libtrace) {
        libtrace->format_data = malloc(sizeof(struct pcapfile_format_data_t));

        DATA(libtrace)->file=NULL;

        return 0;
}

static uint16_t swaps(libtrace_t *libtrace, uint16_t num)
{
        if (DATA(libtrace)->header.magic_number == 0xd4c3b2a1)
                return ((num<<8)&0xFF00)|((num>>8)&0x00FF);
        return num;
}

static uint32_t swapl(libtrace_t *libtrace, uint32_t num)
{
        if (DATA(libtrace)->header.magic_number == 0xd4c3b2a1)
                return 
                           ((num&0x000000FF)<<24)
                        || ((num&0x0000FF00)<<8)
                        || ((num&0x00FF0000)>>8)
                        || ((num&0xFF000000)>>24);
        return num;
}


static int pcapfile_start_input(libtrace_t *libtrace) 
{
        int err;

        if (!DATA(libtrace)->file) {
                DATA(libtrace)->file=trace_open_file(libtrace);

                if (!DATA(libtrace)->file)
                        return -1;

                err=libtrace_io_read(DATA(libtrace)->file,
                                &DATA(libtrace)->header,
                                sizeof(DATA(libtrace)->header));

                if (err<1)
                        return -1;
                
                if (swapl(libtrace,DATA(libtrace)->header.magic_number) != 0xa1b2c3d4) {
                        trace_set_err(libtrace,TRACE_ERR_BAD_PACKET,"Not a pcap tracefile\n");
                        return -1; /* Not a pcap file */
                }

                if (swaps(libtrace,DATA(libtrace)->header.version_major)!=2
                        && swaps(libtrace,DATA(libtrace)->header.version_minor)!=4) {
                        trace_set_err(libtrace,TRACE_ERR_BAD_PACKET,"Unknown pcap tracefile version %d.%d\n",
                                        swaps(libtrace,
                                                DATA(libtrace)->header.version_major),
                                        swaps(libtrace,
                                                DATA(libtrace)->header.version_minor));
                        return -1;
                }

        }

        return 0;
}

static int pcapfile_config_input(libtrace_t *libtrace,
                trace_option_t option,
                void *data)
{
        trace_set_err(libtrace,TRACE_ERR_UNKNOWN_OPTION,
                        "Unknown option %i", option);
        return -1;
}

static int pcapfile_fin_input(libtrace_t *libtrace) 
{
        libtrace_io_close(DATA(libtrace)->file);
        free(libtrace->format_data);
        return 0; /* success */
}

struct pcapfile_pkt_hdr_t {
        uint32_t ts_sec;
        uint32_t ts_usec;
        uint32_t caplen;
        uint32_t wirelen;
};

static int pcapfile_read_packet(struct libtrace_t *libtrace, struct libtrace_packet_t *packet) {
        int err;

        assert(libtrace->format_data);

        packet->type = pcap_dlt_to_rt(swapl(libtrace,
                                DATA(libtrace)->header.network));

        if (!packet->buffer || packet->buf_control == TRACE_CTRL_EXTERNAL) {
                packet->buffer = malloc(LIBTRACE_PACKET_BUFSIZE);
                packet->buf_control = TRACE_CTRL_PACKET;
        }

        err=libtrace_io_read(DATA(libtrace)->file,
                        packet->buffer,
                        sizeof(struct pcapfile_pkt_hdr_t));

        if (err<0) {
                trace_set_err(libtrace,errno,"reading packet");
                return -1;
        }
        if (err==0) {
                /* EOF */
                return 0;
        }

        packet->header = packet->buffer;


        err=libtrace_io_read(DATA(libtrace)->file,
                        (char*)packet->buffer+sizeof(struct pcapfile_pkt_hdr_t),
                        swapl(libtrace,((struct pcapfile_pkt_hdr_t*)packet->buffer)->caplen)
                        );

        
        if (err<0) {
                trace_set_err(libtrace,errno,"reading packet");
                return -1;
        }
        if (err==0) {
                return 0;
        }

        packet->payload = (char*)packet->buffer 
                + sizeof(struct pcapfile_pkt_hdr_t);
        
        return sizeof(struct pcapfile_pkt_hdr_t)
                +swapl(libtrace,((struct pcapfile_pkt_hdr_t*)packet->buffer)->caplen);
}


static libtrace_linktype_t pcapfile_get_link_type(
                const libtrace_packet_t *packet) 
{

        return pcap_dlt_to_libtrace(
                        swapl(packet->trace,
                                DATA(packet->trace)->header.network
                             )
                        );
}

static int8_t pcapfile_get_direction(const libtrace_packet_t *packet) 
{
        int8_t direction  = -1;
        switch(pcapfile_get_link_type(packet)) {
                case TRACE_TYPE_LINUX_SLL:
                {
                        libtrace_sll_header_t *sll;
                        sll = trace_get_link(packet);
                        if (!sll) {
                                trace_set_err(packet->trace,
                                        TRACE_ERR_BAD_PACKET,
                                                "Bad or missing packet");
                                return -1;
                        }
                        /* 0 == LINUX_SLL_HOST */
                        /* the Waikato Capture point defines "packets
                         * originating locally" (ie, outbound), with a
                         * direction of 0, and "packets destined locally"
                         * (ie, inbound), with a direction of 1.
                         * This is kind-of-opposite to LINUX_SLL.
                         * We return consistent values here, however
                         *
                         * Note that in recent versions of pcap, you can
                         * use "inbound" and "outbound" on ppp in linux
                         */
                        if (ntohs(sll->pkttype == 0)) {
                                direction = 1;
                        } else {
                                direction = 0;
                        }
                        break;

                }
                case TRACE_TYPE_PFLOG:
                {
                        libtrace_pflog_header_t *pflog;
                        pflog = trace_get_link(packet);
                        if (!pflog) {
                                trace_set_err(packet->trace,
                                                TRACE_ERR_BAD_PACKET,
                                                "Bad or missing packet");
                                return -1;
                        }
                        /* enum    { PF_IN=0, PF_OUT=1 }; */
                        if (ntohs(pflog->dir==0)) {

                                direction = 1;
                        }
                        else {
                                direction = 0;
                        }
                        break;
                }
                default:
                        break;
        }       
        return direction;
}


static struct timeval pcapfile_get_timeval(
                const struct libtrace_packet_t *packet) 
{
        struct pcapfile_pkt_hdr_t *hdr =
                (struct pcapfile_pkt_hdr_t*)packet->header;
        struct timeval ts;
        ts.tv_sec = swapl(packet->trace,hdr->ts_sec);
        ts.tv_usec = swapl(packet->trace,hdr->ts_usec);
        return ts;
}


static int pcapfile_get_capture_length(const libtrace_packet_t *packet) {
        struct pcapfile_pkt_hdr_t *pcapptr 
                = (struct pcapfile_pkt_hdr_t *)packet->header;

        return swapl(packet->trace,pcapptr->caplen);
}

static int pcapfile_get_wire_length(const libtrace_packet_t *packet) {
        struct pcapfile_pkt_hdr_t *pcapptr 
                = (struct pcapfile_pkt_hdr_t *)packet->header;
        if (packet->type==pcap_dlt_to_rt(TRACE_DLT_EN10MB))
                /* Include the missing FCS */
                return swapl(packet->trace,pcapptr->wirelen)+4; 
        else
                return swapl(packet->trace,pcapptr->wirelen);
}

static int pcapfile_get_framing_length(const libtrace_packet_t *packet UNUSED) {
        return sizeof(struct pcapfile_pkt_hdr_t);
}

static size_t pcapfile_set_capture_length(libtrace_packet_t *packet,size_t size) {
        struct pcapfile_pkt_hdr_t *pcapptr = 0;
        assert(packet);
        if (size > trace_get_capture_length(packet)) {
                /* can't make a packet larger */
                return trace_get_capture_length(packet);
        }
        pcapptr = (struct pcapfile_pkt_hdr_t *)packet->header;
        pcapptr->caplen = swapl(packet->trace,size);
        return trace_get_capture_length(packet);
}

static void pcapfile_help() {
        printf("pcapfile format module: $Revision$\n");
        printf("Supported input URIs:\n");
        printf("\tpcapfile:/path/to/file\n");
        printf("\tpcapfile:/path/to/file.gz\n");
        printf("\n");
        printf("\te.g.: pcapfile:/tmp/trace.pcap\n");
        printf("\n");
}

static struct libtrace_format_t pcapfile = {
        "pcapfile",
        "$Id$",
        TRACE_FORMAT_PCAPFILE,
        pcapfile_init_input,            /* init_input */
        pcapfile_config_input,          /* config_input */
        pcapfile_start_input,           /* start_input */
        NULL,                           /* pause_input */
        NULL,                   /* init_output */
        NULL,                           /* config_output */
        NULL,                           /* start_output */
        pcapfile_fin_input,             /* fin_input */
        NULL,                           /* fin_output */
        pcapfile_read_packet,           /* read_packet */
        NULL,                           /* fin_packet */
        NULL,                           /* write_packet */
        pcapfile_get_link_type,         /* get_link_type */
        pcapfile_get_direction,         /* get_direction */
        NULL,                           /* set_direction */
        NULL,                           /* get_erf_timestamp */
        pcapfile_get_timeval,           /* get_timeval */
        NULL,                           /* get_seconds */
        NULL,                           /* seek_erf */
        NULL,                           /* seek_timeval */
        NULL,                           /* seek_seconds */
        pcapfile_get_capture_length,    /* get_capture_length */
        pcapfile_get_wire_length,       /* get_wire_length */
        pcapfile_get_framing_length,    /* get_framing_length */
        pcapfile_set_capture_length,    /* set_capture_length */
        NULL,                           /* get_fd */
        trace_event_trace,              /* trace_event */
        pcapfile_help,                  /* help */
        NULL                            /* next pointer */
};


void CONSTRUCTOR pcapfile_constructor() {
        register_format(&pcapfile);
}