source: lib/libtrace_int.h @ 823d8e1

/*
 *
 * Copyright (c) 2007-2016 The University of Waikato, Hamilton, New Zealand.
 * All rights reserved.
 *
 * This file is part of libtrace.
 *
 * 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 Lesser General Public License as published by
 * the Free Software Foundation; either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 */
/** @file
 *
 * @brief Header file containing definitions for structures and functions that
 * are internal
 *
 * @author Daniel Lawson
 * @author Perry Lorier
 * @author Shane Alcock
 *
 * @version $Id$
 *
 * All of the structures and functions defined in this header file are intended
 * for internal use within Libtrace only. They should not be exported as part
 * of the library API as we don't want users accessing things like the
 * contents of the libtrace packet structure directly!
 */
#ifndef LIBTRACE_INT_H
#define LIBTRACE_INT_H

#ifdef __cplusplus
extern "C" {
#endif

#include "config.h"
#include "common.h"
#include "libtrace_parallel.h"
#include "wandio.h"
#include "lt_bswap.h"

#ifdef _MSC_VER
// warning: deprecated function
#pragma warning(disable:4996)
// warning: benign redefinitions of types
#pragma warning(disable:4142)
#endif

#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#else
# include "lt_inttypes.h"
#endif

#ifdef HAVE_STDDEF_H
# include <stddef.h>
#else
#ifndef WIN32
# error "Can't find stddev.h -- do you define ptrdiff_t elsewhere?"
#endif
#endif


#include "rt_protocol.h"
        
/* Prefer net/bpf.h over pcap-bpf.h for format_bpf.c on MacOS */
#ifdef HAVE_NET_BPF_H
#    include <net/bpf.h>
#    define HAVE_BPF 1
#else
#ifdef HAVE_PCAP_BPF_H
#  include <pcap-bpf.h>
#  define HAVE_BPF 1
#endif
#endif

#ifdef HAVE_PCAP_H
#  include <pcap.h>
#  ifdef HAVE_PCAP_INT_H
#    include <pcap-int.h>
#  endif
#endif 

#ifdef HAVE_ZLIB_H
#  include <zlib.h>
#endif

#if !HAVE_DECL_STRNDUP
char *strndup(const char *s, size_t size);
#endif

#if !HAVE_DECL_STRNCASECMP
# ifndef HAVE__STRNICMP
/** A local implementation of strncasecmp (as some systems do not have it) */
int strncasecmp(const char *str1, const char *str2, size_t n);
# else
# define strncasecmp _strnicmp
# endif
#endif

#if !HAVE_DECL_SNPRINTF
# ifndef HAVE_SPRINTF_S
/** A local implementation of snprintf (as some systems do not have it) */
int snprintf(char *str, size_t size, const char *format, ...);
# else
# define snprintf sprintf_s
# endif 
#endif

#include "daglegacy.h"
        
#ifdef HAVE_DAG_API
#  include "dagnew.h"
#  include "dagapi.h"
#       if DAG_VERSION == 24
#               include <erftypes.h>
#       else
#               include <daginf.h>
#       endif
#  include "erftypes.h"
#else
#  include "dagformat.h"
#endif

#ifdef HAVE_LLVM
#include "bpf-jit/bpf-jit.h"
#endif

#include "data-struct/ring_buffer.h"
#include "data-struct/object_cache.h"
#include "data-struct/vector.h"
#include "data-struct/message_queue.h"
#include "data-struct/deque.h"
#include "data-struct/linked_list.h"
#include "data-struct/sliding_window.h"
#include "data-struct/buckets.h"
#include "pthread_spinlock.h"

//#define RP_BUFSIZE 65536U

#define LIBTRACE_MAX_REPLAY_SPEEDUP 1000

/** Data about the most recent event from a trace file */
struct libtrace_event_status_t {
        /** A libtrace packet to store the packet when a PACKET event occurs */
        libtrace_packet_t *packet;

        /* The walltime when we processed the first packet from the trace */
        double first_now;

        /* The tracetime of the first packet in the trace */
        double first_ts;

        /** The size of the current PACKET event */
        int psize;
        /** Whether there is a packet stored in *packet above waiting for an
         * event to occur */
        bool waiting;
};

enum thread_types {
        THREAD_EMPTY,
        THREAD_HASHER,
        THREAD_PERPKT,
        THREAD_REPORTER,
        THREAD_KEEPALIVE
};

enum thread_states {
        THREAD_RUNNING,
        THREAD_FINISHING,
        THREAD_FINISHED,
        THREAD_PAUSED,
        THREAD_STATE_MAX
};

enum hash_owner {
        HASH_OWNED_LIBTRACE,
        HASH_OWNED_EXTERNAL,
};

/**
 * Information of this thread
 */
struct libtrace_thread_t {
        uint64_t accepted_packets; // The number of packets accepted only used if pread
        uint64_t filtered_packets;
        // is retreving packets
        // Set to true once the first packet has been stored
        bool recorded_first;
        // For thread safety reason we actually must store this here
        int64_t tracetime_offset_usec;
        void* user_data; // TLS for the user to use
        void* format_data; // TLS for the format to use
        libtrace_message_queue_t messages; // Message handling
        libtrace_ringbuffer_t rbuffer; // Input
        libtrace_t * trace;
        void* ret;
        enum thread_types type;
        enum thread_states state;
        pthread_t tid;
        int perpkt_num; // A number from 0-X that represents this perpkt threads number
                                // in the table, intended to quickly identify this thread
                                // -1 represents NA (such as the case this is not a perpkt thread)
} ALIGN_STRUCT(CACHE_LINE_SIZE);

/**
 * Storage to note time value against each.
 * Used both internally to do trace time playback
 * and can be used externally to assist applications which need
 * a trace starting time such as tracertstats.
 */
struct first_packets {
        pthread_spinlock_t lock;
        size_t count; // If == perpkt_thread_count threads we have all
        size_t first; // Valid if count != 0
        struct {
                libtrace_packet_t * packet;
                struct timeval tv;
        } * packets;
};

#define TRACE_STATES \
        X(STATE_NEW) \
        X(STATE_RUNNING) \
        X(STATE_PAUSING) \
        X(STATE_PAUSED) \
        X(STATE_FINISHED) \
        X(STATE_FINISHING) \
        X(STATE_DESTROYED) \
        X(STATE_JOINED) \
        X(STATE_ERROR)

#define X(a) a,
enum trace_state {
        TRACE_STATES
};
#undef X

#define X(a) case a: return #a;
static inline char *get_trace_state_name(enum trace_state ts){
        switch(ts) {
                TRACE_STATES
                default:
                        return "UNKNOWN";
        }
}
#undef X

#define READ_EOF 0
#define READ_ERROR -1
#define READ_MESSAGE -2
// Used for inband tick message
#define READ_TICK -3

/**
 * Tuning the parallel sizes
 * See the user documentation trace_set_x
 */
struct user_configuration {
        size_t cache_size;
        size_t thread_cache_size;
        bool fixed_count;
        size_t burst_size;
        size_t tick_interval;
        size_t tick_count;
        size_t perpkt_threads;
        size_t hasher_queue_size;
        bool hasher_polling;
        bool reporter_polling;
        size_t reporter_thold;
        bool debug_state;
};
#define ZERO_USER_CONFIG(config) memset(&config, 0, sizeof(struct user_configuration));

struct callback_set {

        fn_cb_starting message_starting;
        fn_cb_dataless message_stopping;
        fn_cb_dataless message_resuming;
        fn_cb_dataless message_pausing;
        fn_cb_packet message_packet;
        fn_cb_result message_result;
        fn_cb_first_packet message_first_packet;
        fn_cb_tick message_tick_count;
        fn_cb_tick message_tick_interval;
        fn_cb_usermessage message_user;
};

/** A libtrace input trace 
 * @internal
 */
struct libtrace_t {
        /** The capture format for the input trace */
        struct libtrace_format_t *format; 
        /** Details of the most recent PACKET event reported by the trace */
        struct libtrace_event_status_t event;
        /** Pointer to the "global" data for the capture format module */       
        void *format_data;              
        /** A BPF filter to be applied to all packets read by the trace - 
         * used only if the capture format does not support filters natively */
        struct libtrace_filter_t *filter; 
        /** The snap length to be applied to all packets read by the trace - 
         * used only if the capture format does not support snapping natively */
        size_t snaplen;                 
        /** Speed up the packet rate when using trace_event() to process trace
         * files by this factor. */
        int replayspeedup;
        /** Count of the number of packets returned to the libtrace user */
        uint64_t accepted_packets;
        /** Count of the number of packets filtered by libtrace */
        uint64_t filtered_packets;
        /** The sequence is like accepted_packets but we don't reset this after a pause. */
        uint64_t sequence_number;
        /** The packet read out by the trace, backwards compatibility to allow us to finalise
         * a packet when the trace is destroyed */
        libtrace_packet_t *last_packet;
        /** The filename from the uri for the trace */
        char *uridata;
        /** The libtrace IO reader for this trace (if applicable) */
        io_t *io;
        /** Error information for the trace */
        libtrace_err_t err;
        /** Boolean flag indicating whether the trace has been started */
        bool started;
        /** Synchronise writes/reads across this format object and attached threads etc */
        pthread_mutex_t libtrace_lock;
        /** Packet read lock, seperate from libtrace_lock as to not block while reading a burst */
        pthread_mutex_t read_packet_lock;
        /** State */
        enum trace_state state;
        /** Use to control pausing threads and finishing threads etc always used with libtrace_lock */
        pthread_cond_t perpkt_cond;
        /** Keeps track of counts of threads in any given state */
        int perpkt_thread_states[THREAD_STATE_MAX]; 

        /** Set to indicate a perpkt's queue is full as such the writing perpkt cannot proceed */
        bool perpkt_queue_full;
        /** Global storage for this trace, shared among all the threads  */
        void* global_blob;
        /** The actual freelist */
        libtrace_ocache_t packet_freelist;
        /** The hasher function */
        enum hasher_types hasher_type;
        /** The hasher function - NULL implies they don't care or balance */
        fn_hasher hasher;
        void *hasher_data;
        enum hash_owner hasher_owner;
        /** The pread_packet choosen path for the configuration */
        int (*pread)(libtrace_t *, libtrace_thread_t *, libtrace_packet_t **, size_t);

        libtrace_thread_t hasher_thread;
        libtrace_thread_t reporter_thread;
        libtrace_thread_t keepalive_thread;
        int perpkt_thread_count;
        libtrace_thread_t * perpkt_threads; // All our perpkt threads
        // Used to keep track of the first packet seen on each thread
        struct first_packets first_packets;
        int tracetime;

        /*
         * Caches statistic counters in the case that our trace is
         * paused or stopped before this counter is taken
         */
        libtrace_stat_t *stats;
        struct user_configuration config;
        libtrace_combine_t combiner;
        
        /* Set of callbacks to be executed by per packet threads in response
         * to various messages. */
        struct callback_set *perpkt_cbs;
        /* Set of callbacks to be executed by the reporter thread in response
         * to various messages. */
        struct callback_set *reporter_cbs;
};

#define LIBTRACE_STAT_MAGIC 0x41

void trace_fin_packet(libtrace_packet_t *packet);
void libtrace_zero_thread(libtrace_thread_t * t);
void store_first_packet(libtrace_t *libtrace, libtrace_packet_t *packet, libtrace_thread_t *t);
libtrace_thread_t * get_thread_table(libtrace_t *libtrace);


void send_message(libtrace_t *trace, libtrace_thread_t *target,
                const enum libtrace_messages type,
                libtrace_generic_t data, libtrace_thread_t *sender);

/** A libtrace output trace
 * @internal
 */
struct libtrace_out_t {
        /** The capture format for the output trace */
        struct libtrace_format_t *format;
        /** Pointer to the "global" data for the capture format module */
        void *format_data;              
        /** The filename for the uri for the output trace */
        char *uridata;                  
        /** Error information for the output trace */
        libtrace_err_t err;
        /** Boolean flag indicating whether the trace has been started */
        bool started;
};

/** Sets the error status on an input trace
 *
 * @param trace         The input trace to set the error status for
 * @param errcode       The code for the error - can be a libtrace error code or a regular errno value
 * @param msg           A message to print when reporting the error
 */
void trace_set_err(libtrace_t *trace, int errcode,const char *msg,...) 

                                                                PRINTF(3,4);
/** Sets the error status on an output trace
 *
 * @param trace         The output trace to set the error status for
 * @param errcode       The code for the error - can be a libtrace error code or a regular errno value
 * @param msg           A message to print when reporting the error
 */
void trace_set_err_out(libtrace_out_t *trace, int errcode, const char *msg,...)
                                                                PRINTF(3,4);

/** Clears the cached values for a libtrace packet
 *
 * @param packet        The libtrace packet that requires a cache reset
 */
void trace_clear_cache(libtrace_packet_t *packet);


#ifndef PF_RULESET_NAME_SIZE
#define PF_RULESET_NAME_SIZE 16
#endif

#ifndef IFNAMSIZ
#define IFNAMSIZ 16
#endif


/** A local definition of a PFLOG header */
typedef struct libtrace_pflog_header_t {
        uint8_t    length;      
        sa_family_t   af;
        uint8_t    action;
        uint8_t    reason;
        char       ifname[IFNAMSIZ];
        char       ruleset[PF_RULESET_NAME_SIZE];
        uint32_t   rulenr;
        uint32_t   subrulenr;
        uint8_t    dir;
        uint8_t    pad[3];
} PACKED libtrace_pflog_header_t;

/** A libtrace capture format module */
/* All functions should return -1, or NULL on failure */
struct libtrace_format_t {
        /** The name of this module, used in the libtrace URI to identify the
         * capture format */
        const char *name;
        /** The version of this module */
        const char *version;
        /** The RT protocol type of this module */
        enum base_format_t type;


        /** Given a filename, return if this is the most likely capture format
         * (used for devices). Used to "guess" the capture format when the
         * URI is not fully specified.
         *
         * @param fname         The name of the device or file to examine
         * @return 1 if the name matches the capture format, 0 otherwise
         */
        int (*probe_filename)(const char *fname);
        
        /** Given a file, looks at the start of the file to determine if this
         * is the capture format. Used to "guess" the capture format when the
         * URI is not fully specified.
         *
         * @param io            An open libtrace IO reader for the file to check
         * @return 1 if the file matches the capture format, 0 otherwise
         */
        int (*probe_magic)(io_t *io);

        /** Initialises an input trace using the capture format.
         *
         * @param libtrace      The input trace to be initialised
         * @return 0 if successful, -1 in the event of error 
         */
        int (*init_input)(libtrace_t *libtrace);
        
        /** Applies a configuration option to an input trace.
         *
         * @param libtrace      The input trace to apply the option to
         * @param option        The option that is being configured
         * @param value         A pointer to the value that the option is to be
         *                      set to
         * @return 0 if successful, -1 if the option is unsupported or an error
         * occurs
         */
        int (*config_input)(libtrace_t *libtrace,trace_option_t option,void *value);
        /** Starts or unpauses an input trace - note that this function is
         * often the one that opens the file or device for reading.
         *
         * @param libtrace      The input trace to be started or unpaused
         * @return 0 if successful, -1 in the event of error */
        int (*start_input)(libtrace_t *libtrace);

        /** Pauses an input trace - this function should close or detach the
         * file or device that is being read from. 
         *
         * @param libtrace      The input trace to be paused
         * @return 0 if successful, -1 in the event of error
         */
        int (*pause_input)(libtrace_t *libtrace);

        /** Initialises an output trace using the capture format.
         *
         * @param libtrace      The output trace to be initialised
         * @return 0 if successful, -1 in the event of error
         */
        int (*init_output)(libtrace_out_t *libtrace);
        
        /** Applies a configuration option to an output trace.
         *
         * @param libtrace      The output trace to apply the option to 
         * @param option        The option that is being configured
         * @param value         A pointer to the value that the option is to be
         *                      set to
         * @return 0 if successful, -1 if the option is unsupported or an error
         * occurs
         * */
        int (*config_output)(libtrace_out_t *libtrace, trace_option_output_t option, void *value);

        /** Starts an output trace - note that this function is often the one
         * that opens the file or device for writing.
         *
         * @param libtrace      The output trace to be started
         * @return 0 if successful, -1 if an error occurs
         *
         * There is no pause for output traces, as writing is not performed
         * asynchronously.
         */
        int (*start_output)(libtrace_out_t *libtrace);

        /** Concludes an input trace and cleans up the capture format data.
         *
         * @param libtrace      The input trace to be concluded
         * @return 0 if successful, -1 if an error occurs
         *
         * Libtrace will call the pause_input function if the input trace is
         * currently active prior to calling this function.
         */
        int (*fin_input)(libtrace_t *libtrace);

        /** Concludes an output trace and cleans up the capture format data.
         *
         * @param libtrace      The output trace to be concluded
         * @return 0 if successful, -1 if an error occurs
         */
        int (*fin_output)(libtrace_out_t *libtrace);

        /** Reads the next packet from an input trace into the provided packet 
         * structure.
         *
         * @param libtrace      The input trace to read from
         * @param packet        The libtrace packet to read into
         * @return The size of the packet read (in bytes) including the capture
         * framing header, or -1 if an error occurs. 0 is returned in the
         * event of an EOF or -2 in the case of interrupting the parallel API.
         *
         * If no packets are available for reading, this function should block
         * until one appears or return 0 if the end of a trace file has been
         * reached.
         */
        int (*read_packet)(libtrace_t *libtrace, libtrace_packet_t *packet);
        
        /** Converts a buffer containing a packet record into a libtrace packet
         * 
         * @param libtrace      An input trace in the capture format for the 
         *                      packet
         * @param packet        A libtrace packet to put the prepared packet
         *                      into
         * @param buffer        The buffer containing the packet record 
         *                      (including the capture format header)
         * @param rt_type       The RT type for the packet
         * @param flags         Flags describing properties that should be
         *                      applied to the new packet
         * @return 0 if successful, -1 if an error occurs.
         *
         * Updates internal trace and packet details, such as payload pointers,
         * loss counters and packet types to match the packet record provided
         * in the buffer. This is a zero-copy function.
         *
         * Intended (at this stage) only for internal use, particularly by
         * RT which needs to decapsulate RT packets */
        int (*prepare_packet)(libtrace_t *libtrace, libtrace_packet_t *packet,
                        void *buffer, libtrace_rt_types_t rt_type, 
                        uint32_t flags);
        
        /** Frees any resources allocated by the capture format module for a
         * libtrace packet.
         *
         * @param The packet to be finalised
         *       */
        void (*fin_packet)(libtrace_packet_t *packet);

        /** Write a libtrace packet to an output trace.
         *
         * @param libtrace      The output trace to write the packet to
         * @param packet        The packet to be written out
         * @return The number of bytes written, or -1 if an error occurs
         */
        int (*write_packet)(libtrace_out_t *libtrace, libtrace_packet_t *packet);

        /** Flush any buffered output for an output trace.
         *
         * @param libtrace      The output trace to be flushed
         */
        int (*flush_output)(libtrace_out_t *libtrace);

        /** Returns the libtrace link type for a packet.
         *
         * @param packet        The packet to get the link type for
         * @return The libtrace link type, or -1 if this link type is unknown
         */ 
        libtrace_linktype_t (*get_link_type)(const libtrace_packet_t *packet);

        /** Returns the direction of a packet.
         *
         * @param packet        The packet to get the direction for
         * @return The direction of the packet, or -1 if no direction tag is
         * present or an error occurs
         */ 
        libtrace_direction_t (*get_direction)(const libtrace_packet_t *packet);
        
        /** Sets the direction of a packet.
         *
         * @param packet        The packet to set the direction for
         * @param direction     The direction to assign to the packet
         * @return The updated direction for the packet, or -1 if an error
         * occurs
         *
         * @note Some capture formats do not feature direction tagging, so it
         * will not make sense to implement a set_direction function for them.
         */ 
        libtrace_direction_t (*set_direction)(libtrace_packet_t *packet, libtrace_direction_t direction);
        
        /** Returns the timestamp for a packet in the ERF timestamp format.
         *
         * @param packet        The packet to get the timestamp from
         * @return The 64-bit ERF timestamp
         *
         * @note Each format must implement at least one of the four "get 
         * timestamp" functions. 
         *
         * If not implemented, libtrace will convert the result of one of the
         * other timestamp functions into the appropriate format instead. 
         * This means each capture format only needs to implement the most
         * sensible of the four and let libtrace handle any conversions.
         *
         */
        uint64_t (*get_erf_timestamp)(const libtrace_packet_t *packet);

        /** Returns the timestamp for a packet in the timeval format
         *
         * @param packet        The packet to get the timestamp from
         * @return The timestamp from the packet as a timeval
         *
         * @note Each format must implement at least one of the four "get 
         * timestamp" functions. 
         *
         * If not implemented, libtrace will convert the result of one of the
         * other timestamp functions into the appropriate format instead. 
         * This means each capture format only needs to implement the most
         * sensible of the four and let libtrace handle any conversions.
         */
        struct timeval (*get_timeval)(const libtrace_packet_t *packet);
        
        /** Returns the timestamp for a packet in the timespec format.
         *
         * @param packet        The packet to get the timestamp from
         * @return The timestamp from the packet as a timespec
         *
         * @note Each format must implement at least one of the four "get 
         * timestamp" functions. 
         *
         * If not implemented, libtrace will convert the result of one of the
         * other timestamp functions into the appropriate format instead. 
         * This means each capture format only needs to implement the most
         * sensible of the four and let libtrace handle any conversions.
         */
        struct timespec (*get_timespec)(const libtrace_packet_t *packet);
        
        /** Returns the timestamp for a packet in floating point seconds.
         *
         * @param packet        The packet to get the timestamp from
         * @return The timestamp from the packet as a floating point number of
         * seconds since 1970-01-01 00:00:00 UTC
         *
         * @note Each format must implement at least one of the four "get 
         * timestamp" functions. 
         *
         * If not implemented, libtrace will convert the result of one of the
         * other timestamp functions into the appropriate format instead. 
         * This means each capture format only needs to implement the most
         * sensible of the four and let libtrace handle any conversions.
         */
        double (*get_seconds)(const libtrace_packet_t *packet);
        
        /** Moves the read pointer to a certain ERF timestamp within an input 
         * trace file.
         *
         * @param trace         The input trace to seek within
         * @param timestamp     The timestamp to seek to, as an ERF timestamp
         *
         * @return 0 on success, -1 on failure.
         *
         * The next packet read from this trace will now be the first packet
         * to have a timestamp equal to or greater than the provided timestamp.
         *
         * @note Each format that supports seeking must implement at least one
         * of the seek functions.
         *
         * If not implemented, libtrace will convert the timestamp into the
         * appropriate format to use a seek function that has been implemented.
         * This means each capture format only needs to implement the seek
         * function that matches the native timestamp format for that capture.
         *
         */
        int (*seek_erf)(libtrace_t *trace, uint64_t timestamp);
        /** Moves the read pointer to a certain timestamp represented using a
         * timeval within an input trace file.
         *
         * @param trace         The input trace to seek within
         * @param timestamp     The timestamp to seek to, as a timeval
         *
         * @return 0 on success, -1 on failure.
         *
         * The next packet read from this trace will now be the first packet
         * to have a timestamp equal to or greater than the provided timestamp.
         *
         * @note Each format that supports seeking must implement at least one
         * of the seek functions.
         *
         * If not implemented, libtrace will convert the timestamp into the
         * appropriate format to use a seek function that has been implemented.
         * This means each capture format only needs to implement the seek
         * function that matches the native timestamp format for that capture.
         *
         */
        int (*seek_timeval)(libtrace_t *trace, struct timeval tv);
        
        /** Moves the read pointer to a certain timestamp represented using 
         * floating point seconds within an input trace file.
         *
         * @param trace         The input trace to seek within
         * @param timestamp     The timestamp to seek to, as floating point
         *                      seconds since 1970-01-01 00:00:00 UTC
         *
         * @return 0 on success, -1 on failure.
         *
         * The next packet read from this trace will now be the first packet
         * to have a timestamp equal to or greater than the provided timestamp.
         *
         * @note Each format that supports seeking must implement at least one
         * of the seek functions.
         *
         * If not implemented, libtrace will convert the timestamp into the
         * appropriate format to use a seek function that has been implemented.
         * This means each capture format only needs to implement the seek
         * function that matches the native timestamp format for that capture.
         *
         */
        int (*seek_seconds)(libtrace_t *trace, double seconds);
        
        /** Returns the payload length of the captured packet record.
         *
         * @param packet        The packet to get the capture length from
         * @return The capture length for the packet, or -1 if an error occurs
         *
         * Capture length is the current size of the packet record itself,
         * following any truncation that may have occurred during the capture
         * process. This length does not include the capture format framing
         * header.
         */
        int (*get_capture_length)(const libtrace_packet_t *packet);

        /** Returns the original length of the packet as it was on the wire.
         *
         * @param packet        The packet to get the wire length from
         * @return The length of the packet on the wire at the time of capture,
         * or -1 if an error occurs
         *
         * Wire length is the original size of the packet prior to any
         * truncation that may have occurred as part of the capture process.
         * This length does not include the capture format framing header.
         */
        int (*get_wire_length)(const libtrace_packet_t *packet);
        
        /** Returns the length of the capture format framing header
         *
         * @param packet        The packet to get the framing length from
         * @return The length of the framing header, or -1 if an error occurs
         *
         * The framing header is the extra metadata that the capture process
         * records about a packet.  The framing length does not include any
         * of the packet payload itself. The total size of the packet record
         * can be calculated be adding this value with the capture length.
         */
        int (*get_framing_length)(const libtrace_packet_t *packet);

        /** Sets the capture length for a packet.
         *
         * @param packet        The packet to adjust the capture length for.
         * @param size          The new capture length
         * @return The new capture length of the packet, or -1 if an error
         * occurs
         *
         * @note This function should only reduce the capture length. If the
         * provided length is larger than the current capture length, -1 should
         * be returned.
         */
        size_t (*set_capture_length)(struct libtrace_packet_t *packet,size_t size);
        /** Returns the number of packets observed by an input trace.
         *
         * @param trace         The input trace to get the packet count for
         * @return The number of packets observed by an input trace, or
         * UINT64_MAX if the number is unknown
         *
         * This count includes packets that have been filtered and dropped.
         */
        uint64_t (*get_received_packets)(libtrace_t *trace);

        /** Returns the number of packets filtered by an input trace.
         *
         * @param trace         The input trace to get the filtered count for
         * @return The number of packets filtered by the input trace, or
         * UINT64_MAX if the number is unknown
         *
         */
        uint64_t (*get_filtered_packets)(libtrace_t *trace);
        
        /** Returns the number of packets dropped by an input trace.
         *
         * @param trace         The input trace to get the dropped count for
         * @return The number of packets dropped by the input trace, or
         * UINT64_MAX if the number is unknown
         *
         */
        uint64_t (*get_dropped_packets)(libtrace_t *trace);

        /** Returns statistics about a trace.
         *
         * @param trace The libtrace object
         * @param stat [in,out] A statistics structure ready to be filled
         *
         * The filtered and accepted statistics will be set to the values
         * stored in the library. All other statistics are not set.
         *
         * @note If filtering of packets is performed by a trace and the number
         * of filtered packets is unknown this should be marked as invalid by
         * the format.
         */
        void (*get_statistics)(libtrace_t *trace, libtrace_stat_t *stat);
        
        /** Returns the file descriptor used by the input trace.
         *
         * @param trace         The input trace to get the file descriptor for
         * @return The file descriptor used by the input trace to read packets 
         *
         */
        int (*get_fd)(const libtrace_t *trace);
        
        /** Returns the next libtrace event for the input trace.
         *
         * @param trace         The input trace to get the next event from
         * @param packet        A libtrace packet to read a packet into
         * @return A libtrace event describing the event that occured
         *
         * The event API allows for non-blocking reading of packets from an
         * input trace. If a packet is available and ready to be read, a packet
         * event should be returned. Otherwise a sleep or fd event should be
         * returned to indicate that the caller needs to wait. If the input
         * trace has an error or reaches EOF, a terminate event should be
         * returned.
         */
        struct libtrace_eventobj_t (*trace_event)(libtrace_t *trace, libtrace_packet_t *packet);        

        /** Prints some useful help information to standard output. */
        void (*help)(void);
        
        /** Next pointer, should always be NULL - used by the format module
         * manager. */
        struct libtrace_format_t *next;

        /** Holds information about the trace format */
        struct libtrace_info_t info;

        /**
         * Starts or unpauses an input trace in parallel mode - note that
         * this function is often the one that opens the file or device for
         * reading.
         *
         * @param libtrace      The input trace to be started or unpaused
         * @return 0 upon success.
         *         Otherwise in event of an error -1 is returned.
         * 
         */
        int (*pstart_input)(libtrace_t *trace);
        
        /**
         * Read a batch of packets from the input stream related to thread.
         * At most read nb_packets, however should return with less if packets
         * are not waiting. However still must return at least 1, 0 still indicates
         * EOF.
         *
         * @param libtrace      The input trace
         * @param t     The thread
         * @param packets       An array of packets
         * @param nb_packets    The number of packets in the array (the maximum to read)
         * @return The number of packets read, or 0 in the case of EOF or -1 in error or -2 to represent
         * interrupted due to message waiting before packets had been read.
         */
        int (*pread_packets)(libtrace_t *trace, libtrace_thread_t *t, libtrace_packet_t **packets, size_t nb_packets);
        
        /** Pause a parallel trace
         *
         * @param libtrace      The input trace to be paused
         */
        int (*ppause_input)(libtrace_t *trace);
        
        /** Called after all threads have been paused, Finish (close) a parallel trace
         *
         * @param libtrace      The input trace to be stopped
         */
        int (*pfin_input)(libtrace_t *trace);

        /**
         * Register a thread for use with the format or using the packets produced
         * by it. This is NOT only used for threads reading packets in fact all
         * threads use this.
         *
         * The libtrace lock is not held by this format but can be aquired
         * by the format.
         *
         * Some use cases include setting up any thread local storage required for
         * to read packets and free packets. For DPDK we require any thread that
         * may release or read a packet to have have an internal number associated
         * with it.
         * 
         * The thread type can be used to see if this thread is going to be used
         * to read packets or otherwise.
         *
         * @return 0 if successful, -1 if the option is unsupported or an error
         * occurs (such as a maximum of threads being reached)
         */
        int (*pregister_thread)(libtrace_t *libtrace, libtrace_thread_t *t, bool reader);

        /**
         * If needed any memory allocated with pregister_thread can be released
         * in this function. The thread will be destroyed directly after this
         * function is called.
         */
        void (*punregister_thread)(libtrace_t *libtrace, libtrace_thread_t *t);

        /** Returns statistics for a single thread.
         *
         * @param trace The libtrace object
         * @param t The thread to return statistics for
         * @param stat [in,out] A statistics structure ready to be filled
         *
         * The filtered and accepted statistics will be set to the values
         * stored in the library. All other statistics are not set.
         *
         * @note If filtering of packets is performed by a trace and the number
         * of filtered packets is unknown this should be marked as invalid by
         * the format.
         */
        void (*get_thread_statistics)(libtrace_t *libtrace,
                                      libtrace_thread_t *t,
                                      libtrace_stat_t *stat);
};

/** Macro to zero out a single thread format */
#define NON_PARALLEL(live) \
        {live, 1},              /* trace info */ \
        NULL,                   /* pstart_input */ \
        NULL,                   /* pread_packet */ \
        NULL,                   /* ppause_input */ \
        NULL,                   /* pfin_input */ \
        NULL,                   /* pregister_thread */ \
        NULL,                   /* punregister_thread */ \
        NULL,                   /* get_thread_statistics */

/** The list of registered capture formats */
//extern struct libtrace_format_t *form;

/** Specifies whether any blocking packet readers should cease reading 
 * immediately
 */
extern volatile int libtrace_halt;

/**
 * Used by a format to check if trace_interrupt or if a trace_pause/stop has
 * been called. Provides backwards compatibility with traditional read
 * functions when trace_read_packet() is used by the parallel API.
 *
 * Returns -1 if not halting otherwise returns the code that the read
 * operation should pass on.
 */
static inline int is_halted(libtrace_t *trace) {
        if (!(libtrace_halt || trace->state == STATE_PAUSING)) {
                return -1;
        } else if (libtrace_halt) {
                return READ_EOF;
        } else {
                return READ_MESSAGE;
        }
}

/** Registers a new capture format module.
 *
 * @param format        The format module to be registered
 */
void register_format(struct libtrace_format_t *format);

/** Converts a timeval into a timestamp in microseconds since the epoch.
 *
 * @param tv    The timeval to be converted.
 * @return A 64 bit timestamp in microseconds since the epoch.
 */
uint64_t tv_to_usec(const struct timeval *tv);

/** Converts a PCAP DLT into a libtrace link type.
 *
 * @param linktype      The PCAP DLT to be converted
 * @return The libtrace link type that is equivalent to the provided DLT, or 
 * -1 if the DLT is unknown
 */
libtrace_linktype_t pcap_linktype_to_libtrace(libtrace_dlt_t linktype);

/** Converts a PCAP DLT into an RT protocol type.
 *
 * @param linktype      The PCAP DLT to be converted
 * @return The RT type that is equivalent to the provided DLT
 */
libtrace_rt_types_t pcap_linktype_to_rt(libtrace_dlt_t linktype);

/** Converts a PCAP-NG DLT into an RT protocol type.
 *
 * @param linktype      The PCAP DLT to be converted
 * @return The RT type that is equivalent to the provided DLT
 */
libtrace_rt_types_t pcapng_linktype_to_rt(libtrace_dlt_t linktype);

/** Converts a libtrace link type into a PCAP linktype.
 *
 * @param type          The libtrace link type to be converted
 * @return The PCAP linktype that is equivalent to the provided libtrace link 
 * type, or -1 if the link type is unknown
 */
libtrace_dlt_t libtrace_to_pcap_linktype(libtrace_linktype_t type);

/** Converts a libtrace link type into a PCAP DLT.
 *
 * @param type          The libtrace link type to be converted
 * @return The PCAP DLT that is equivalent to the provided libtrace link
 * type, or -1 if the link type is unknown
 */
libtrace_dlt_t libtrace_to_pcap_dlt(libtrace_linktype_t type);

/** Converts an RT protocol type into a PCAP DLT.
 *
 * @param rt_type       The RT type to be converted
 * @return The PCAP DLT that is equivalent to the provided RT protocol
 */
libtrace_dlt_t rt_to_pcap_linktype(libtrace_rt_types_t rt_type);

/** Converts a PCAP DLT into an RT protocol type for the BPF format.
 *
 * @param linktype      The PCAP DLT to be converted
 * @return The RT type that is equivalent to the provided DLT for BPF
 */
libtrace_rt_types_t bpf_linktype_to_rt(libtrace_dlt_t linktype);

/** Converts an ERF type into a libtrace link type.
 *
 * @param erf           The ERF type to be converted
 * @return The libtrace link type that is equivalent to the provided ERF type,
 * or -1 if the ERF type is unknown
 */
libtrace_linktype_t erf_type_to_libtrace(uint8_t erf);

/** Converts a libtrace link type into an ERF type.
 *
 * @param linktype      The libtrace link type to be converted
 * @return The ERF type that is equivalent to the provided libtrace link type,
 * or -1 if the link type cannot be matched to an ERF type.
 */
uint8_t libtrace_to_erf_type(libtrace_linktype_t linktype);

/** Converts an ARPHRD type into a libtrace link type.
 *
 * @param arphrd        The ARPHRD type to be converted
 * @return The libtrace link type that is equivalent to the provided ARPHRD
 * type, or -1 if the ARPHRD type is unknown
 */
libtrace_linktype_t arphrd_type_to_libtrace(unsigned int arphrd);

/** Converts a libtrace link type into an ARPHRD type.
 *
 * @param type          The libtrace link type to be converted
 * @return The ARPHRD type that is equivalent to the provided libtrace link
 * type, or -1 if the link type cannot be matched to an ARPHRD type
 */
unsigned int libtrace_to_arphrd_type(libtrace_linktype_t type);

/** Converts a libtrace packet to the Linux SLL type.
 *
 * @param packet        The packet to be promoted
 *
 * @note This will involve memcpy() so use sparingly.
 *
 * This function prepends a Linux SLL header to a packet so that we can store
 * direction tagging information.
 */
void promote_packet(libtrace_packet_t *packet);

/** Attempts to demote a packet by removing the first header.
 *
 * @param packet        The packet to be demoted
 * @return True if the packet was demoted, false otherwise.
 *
 * Essentially the opposite of promote_packet, except that it will also remove
 * an ATM header as well as Linux SLL.
 *
 */
bool demote_packet(libtrace_packet_t *packet);

/** Returns a pointer to the header following a Linux SLL header.
 *
 * @param link          A pointer to the Linux SLL header to be skipped
 * @param[out] arphrd_type      The arp hardware type of the packet
 * @param[out] next_header      The ethertype of the next header
 * @param[in,out] remaining     Updated with the number of captured bytes
 *                              remaining
 * @return A pointer to the header following the Linux SLL header, or NULL if
 * no subsequent header is present.
 *
 * Remaining must point to the number of bytes captured from the Linux SLL 
 * header and beyond.  It will be decremented by the number of bytes skipped
 * to find the payload.
 *
 * If the Linux SLL header is complete but there are zero bytes of payload 
 * after the end of the header, a pointer to where the payload would be is
 * returned and remaining will be set to zero. If the Linux SLL header is
 * incomplete (truncated), then NULL is returned and remaining will be set to
 * 0. Therefore, it is very important to check the value of remaining after
 * calling this function.
 */     
void *trace_get_payload_from_linux_sll(const void *link,
                uint16_t *arphrd_type, 
                uint16_t *next_header, 
                uint32_t *remaining);

/** Returns a pointer to the header following an ATM header.
 *
 * @param link          A pointer to the ATM header to be skipped
 * @param[out] type     The ethertype of the next header
 * @param[in,out] remaining     Updated with the number of captured bytes
 *                              remaining
 * @return A pointer to the header following the ATM header, or NULL if
 * no subsequent header is present.
 *
 * Remaining must point to the number of bytes captured from the ATM header
 * and beyond.  It will be decremented by the number of bytes skipped to find
 * the payload.
 *
 * If the ATM header is complete but there are zero bytes of payload 
 * after the end of the header, a pointer to where the payload would be is
 * returned and remaining will be set to zero. If the ATM header is
 * incomplete (truncated), then NULL is returned and remaining will be set to
 * 0. Therefore, it is very important to check the value of remaining after
 * calling this function.
 */     
DLLEXPORT void *trace_get_payload_from_atm(void *link, uint8_t *type, 
                uint32_t *remaining);


#ifdef HAVE_BPF
/* A type encapsulating a bpf filter
 * This type covers the compiled bpf filter, as well as the original filter
 * string
 *
 */

/** Internal representation of a BPF filter */
struct libtrace_filter_t {
        struct bpf_program filter;      /**< The BPF program itself */
        char * filterstring;            /**< The filter string */
        int flag;                       /**< Indicates if the filter is valid */
        struct bpf_jit_t *jitfilter;
};
#else
/** BPF not supported by this system, but we still need to define a structure
 * for the filter */
struct libtrace_filter_t {};
#endif

/** Local definition of a PCAP header */
typedef struct libtrace_pcapfile_pkt_hdr_t {
        uint32_t ts_sec;        /* Seconds portion of the timestamp */
        uint32_t ts_usec;       /* Microseconds portion of the timestamp */
        uint32_t caplen;        /* Capture length of the packet */
        uint32_t wirelen;       /* The wire length of the packet */
} libtrace_pcapfile_pkt_hdr_t;

#ifdef HAVE_DAG
/** Constructor for the DAG format module */
void dag_constructor(void);
#endif
/** Constructor for the ERF format module */
void erf_constructor(void);
/** Constructor for the TSH format module */
void tsh_constructor(void);
/** Constructor for the Legacy DAG format module */
void legacy_constructor(void);
/** Constructor for the Linux Native format module */
void linuxnative_constructor(void);
/** Constructor for the Linux Ring format module */
void linuxring_constructor(void);
/** Constructor for the PCAP format module */
void pcap_constructor(void);
/** Constructor for the PCAP File format module */
void pcapfile_constructor(void);
/** Constructor for the PCAP-NG File format module */
void pcapng_constructor(void);
/** Constructor for the RT format module */
void rt_constructor(void);
/** Constructor for the DUCK format module */
void duck_constructor(void);
/** Constructor for the ATM Header format module */
void atmhdr_constructor(void);
/** Constructor for the network DAG format module */
void ndag_constructor(void);
/** Constructor for the live ETSI over TCP format module */
void etsilive_constructor(void);
#ifdef HAVE_BPF
/** Constructor for the BPF format module */
void bpf_constructor(void);
#endif
#if HAVE_DPDK
/** Constructor for Intels DPDK format module */
void dpdk_constructor(void);

/** Constructor for receiving network DAG via Intels DPDK format module */
void dpdkndag_constructor(void);

#endif

/** Extracts the RadioTap flags from a wireless link header
 *
 * @param link          A pointer to the wireless link header
 * @param linktype      The link type of the wireless header
 * @param[out] flags    Space to store the extracted flags
 * @return True if libtrace was able to extract flags from the link header,
 * false otherwise.
 *
 * This function has been left internal because it is not portable across
 * drivers.
 */
bool trace_get_wireless_flags(void *link, libtrace_linktype_t linktype, uint8_t *flags);
#define TRACE_RADIOTAP_F_FCS 0x10
        
#ifdef __cplusplus
}
#endif

#endif /* LIBTRACE_INT_H */