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nsock_internal.h

/***************************************************************************
 * nsock_internal.h -- PRIVATE interface definitions for the guts of the   *
 * nsock paralle socket event library.  Applications calling this library  *
 * should NOT include this. even LOOK at these :).                         *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
 *                                                                         *
 * The nsock parallel socket event library is (C) 1999-2004 Insecure.Com   *
 * LLC This library is free software; you may redistribute and/or          *
 * modify it under the terms of the GNU General Public License as          *
 * published by the Free Software Foundation; Version 2.  This guarantees  *
 * your right to use, modify, and redistribute this software under certain *
 * conditions.  If this license is unacceptable to you, Insecure.Com LLC   *
 * may be willing to sell alternative licenses (contact                    *
 * sales@insecure.com ).                                                   *
 *                                                                         *
 * As a special exception to the GPL terms, Insecure.Com LLC grants        *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included Copying.OpenSSL file, and distribute linked      *
 * combinations including the two. You must obey the GNU GPL in all        *
 * respects for all of the code used other than OpenSSL.  If you modify    *
 * this file, you may extend this exception to your version of the file,   *
 * but you are not obligated to do so.                                     *
 *                                                                         * 
 * If you received these files with a written license agreement stating    *
 * terms other than the (GPL) terms above, then that alternative license   *
 * agreement takes precedence over this comment.                          *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes (none     *
 * have been found so far).                                                *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to fyodor@insecure.org for possible incorporation into the main         *
 * distribution.  By sending these changes to Fyodor or one the            *
 * insecure.org development mailing lists, it is assumed that you are      *
 * offering Fyodor and Insecure.Com LLC the unlimited, non-exclusive right *
 * to reuse, modify, and relicense the code.  Nmap will always be          *
 * available Open Source, but this is important because the inability to   *
 * relicense code has caused devastating problems for other Free Software  *
 * projects (such as KDE and NASM).  We also occasionally relicense the    *
 * code to third parties as discussed above.  If you wish to specify       *
 * special license conditions of your contributions, just say so when you  *
 * send them.                                                              *
 *                                                                         *
 * 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 (                               *
 * http://www.gnu.org/copyleft/gpl.html ).                                 *
 *                                                                         *
 ***************************************************************************/

/* $Id: nsock_internal.h,v 1.19 2004/10/12 09:34:12 fyodor Exp $ */

#ifndef NSOCK_INTERNAL_H
#define NSOCK_INTERNAL_H

#include <nbase.h>

#ifdef HAVE_CONFIG_H
#include "nsock_config.h"
#include "nbase_config.h"
#endif

#ifdef WIN32
#include "nbase_winconfig.h"
#include <Winsock2.h>
#endif

#include "gh_list.h"
#include "filespace.h"
#include "nsock.h" /* The public interface -- I need it for some enum defs */
#include "nsock_ssl.h"

#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_STRINGS_H
#include <strings.h>
#endif

#include "nsock_utils.h"

/*********      STRUCTURES   **************/

/* This is geared to handling state for select calls, perhaps at 
   some point I'll add a USE_POLL_NOT_SELECT define which causes it to
   do poll()s instead. */
struct nsock_io_info {
  fd_set fds_master_r; /* Descriptors from which have pending READ events */
  fd_set fds_master_w; /* Descriptors which we are tryint to WRITE to */
  fd_set fds_master_x; /* looking for exceptional events -- used with connect */

  /* For keeping track of the select results */
  fd_set fds_results_r, fds_results_w, fds_results_x;

/* The highest sd we have set in any of our fd_set's (max_sd + 1 is
   used in select() calls).  Note that it can be -1, when there are no
   valid sockets */
  int max_sd; 
  int results_left; /* The number of descriptors contained in the sets that
                   we have not yet dealt with. */
};

struct event_lists {
  /* We keep the events seperate because we want to handle them in the 
     order: connect => read => write => timer for several reasons:
     1) Makes sure we have gone through all the net i/o events before 
        a timer expires (would be a shame to timeout after the data was 
        available but before we delivered the events
     2) The connect() results often lead to a read or write that can be 
        processed in the same cycle.  In the same way, read() often 
      leads to write().
  */
  gh_list connect_events;
  gh_list read_events;
  gh_list write_events;
  gh_list timer_events;
  gh_list free_events; /* When an event is deleted, we stick it here for
                    later reuse */
  struct timeval next_ev; /* The soonest time that either a timer event goes
                       off or a read/write/connect expires.  It is 
                       updated each main loop round as we go through 
                       the events.  It is an absolute time.  If there
                       are no events, tv_sec is 0 */
  int events_pending; /* Number of events pending (total) on all lists */

};

enum nsock_read_types { NSOCK_READLINES, NSOCK_READBYTES, NSOCK_READ };

struct readinfo {
  enum nsock_read_types read_type;
  int num; /* num lines; num bytes; whatever (depends on read_type) */
};

struct writeinfo {
  int written_so_far; /* Number of bytes successfully written */
};

/* struct sslinfo defined in nsock_ssl.h */

/* remember that callers of this library should NOT be accessing these 
   fields directly */
typedef struct  {
  unsigned long id; /* Every mst has a unique (accross the 
                   program execution) id */

  struct nsock_io_info mioi;  /* info for keeping track of select() I/O */
  struct event_lists evl; /* Lists of pending events we are waiting on */
  
  void *userdata; /* User Data, if it has been set.  Otherwise NULL */
  gh_list free_iods; /* msiod structures that have been freed for reuse */
  gh_list active_iods; /* msiod structures that have been allocated */
  unsigned long next_event_serial; /* serial # of next event (used to create
                              next nsock_event_id */
  unsigned long next_iod_serial; /* Serial # of next iod to be created */
  int errnum; /* If nsock_loop() returns NSOCK_LOOP_ERROR, this is where we
            describe the error (errnum fashion) */
  int tracelevel; /* Trace/debug level - set by nsp_settrace.  If positive, trace logs are printted to
                 stdout */
  /* This time is subtracted from the current time for trace reports */
  struct timeval tracebasetime; 
} mspool;


typedef struct msevent msevent;

typedef struct msiod msiod;

enum msiod_state { NSIOD_STATE_DELETED, NSIOD_STATE_INITIAL, 
               NSIOD_STATE_UNKNOWN /* sd was provided to us in nsi_new2 */,
               NSIOD_STATE_CONNECTED_TCP, NSIOD_STATE_CONNECTED_UDP };

/* typedef struct msiod msiod; */

/* nsock_iod is like a "file descriptor" for the nsock library.  You
   use it to request events. */
struct msiod {
  int sd; /* The socket descriptor related to the event */
  int events_pending; /* Number of pending events on this iod */
  mspool *nsp; /* The mspool used to create the iod (used for deletion) */
  enum msiod_state state;
  struct sockaddr_storage peer; /* The host and port we are connected to
                           using sd (saves a call to getpeername) */

/* The length of peer actualy used (sizeof(sockadd_in) or
   sizeof(sockaddr_in6), or 0 if peer has not been filled in */
  size_t peerlen; 
  int lastproto; /* -1 if none yet, otherwise IPPROTO_TCP, etc. */
  gh_list_elem *entry_in_nsp_active_iods; /* The mspool keeps track of
                                   msiods that have been
                                   allocated so that it can
                                   destroy them if the msp
                                   is deleted.  This pointer
                                   makes it easy to remove
                                   this msiod from the
                                   allocated list when
                                   neccessary */
#if HAVE_OPENSSL
  SSL *ssl; /* An SSL connection (or NULL if none) */
  SSL_SESSION *ssl_session; /* SSL SESSION ID (or NULL if none) */
#else
  char *ssl; /* Because there are many if (nsi->ssl) cases in the code */
#endif
  unsigned long id; /* Every iod has an id which is always unique for the
                   same nspool (unless you create billions of them) */
  void *userdata;
};



/* nsock_event_t handles a single event.  Its ID is generally returned when
   the event is created, and the event is included in callbacks */
struct msevent {
  nsock_event_id id; /* Every event has an ID which is unique for a given nsock
              unless you blow through more than 500,000,000 events */
  enum nse_type type;
  enum nse_status status;

  struct filespace iobuf; /* for write events, this is the data to be written,
                       for read events, this is what we will read into */

  struct timeval timeout; /* The timeout of the event -- absolute time
                       except that tv_sec == 0 means no timeout */
  struct readinfo readinfo; /* Info pertaining to READ requests */
  struct writeinfo writeinfo; /* Info pertaining to WRITE requests */
#if HAVE_OPENSSL
  struct sslinfo sslinfo;
#endif
  int errnum; /* If we return a status of NSE_STATUS_ERROR, this must be set */
  int eof;
  msiod *iod; /* The nsock I/O descriptor related to event (if applicable) */
  nsock_ev_handler handler; /* The handler to call when event is complete */
  void *userdata;
  int event_done; /* If this event is all filled out and ready for
                 immediate delivery, event_done is nonzero.  Used
                 when event is finished at unexpected time and we
                 want to dispatch it later to avoid duplicating
                 stat update code and all that other crap */
  struct timeval time_created;
};



/*********  PROTOTYPES   **************/

/* Get a new nsock_event_id, given a type */
nsock_event_id get_new_event_id(mspool *nsp, enum nse_type type);
/* Take an event ID and return the type (NSE_TYPE_CONNECT, etc */
enum nse_type get_event_id_type(nsock_event_id event_id);

/* Create a new event structure -- must be deleted later with msevent_delete,
 unless it returns NULL (failure).  NULL can be passed in for the
 msiod and the userdata if not available. */
msevent *msevent_new(mspool *nsp, enum nse_type type, msiod *msiod, 
                 int timeout_msecs, nsock_ev_handler handler,
                 void *userdata);

/* An inernal function for cancelling an event when you already have a
   pointer to the msevent (use nsock_event_cancel if you just have an
   ID).  The event_list passed in should correspond to the type of the
   event.  For example, with NSE_TYPE_READ, you would pass in
   &nsp->evl.read_events;.  elem is the list element in event_list
   which holds the event.  Pass a nonzero for notify if you want the
   program owning the event to be notified that it has been cancelled */
int msevent_cancel(mspool *nsp, msevent *nse, gh_list *event_list, 
               gh_list_elem *elem, int notify);

/* Adjust various statistics, dispatches the event handler (if notify is
   nonzero) and then deletes the event.  This function does NOT delete
   the event from any lists it might be on (eg nsp->evl.read_list etc.) 
   nse->event_done MUST be true when you call this */
void msevent_dispatch_and_delete(mspool *nsp, msevent *nse, int notify);

/* Free an msevent which was allocated with msevent_new, including all
   internal resources.  Note -- we assume that
   nse->iod->events_pending (if it exists) has ALREADY been
   decremented (done during msevent_dispatch_and_delete) -- so
   remember to do this if you call msevent_delete() directly */
void msevent_delete(mspool *nsp, msevent *nse);

/* Adds an event to the appropriate nsp event list, handles housekeeping
   such as adjusting the descriptor select/poll lists, registering the
   timeout value, etc. */
void nsp_add_event(mspool *nsp, msevent *nse);

/* Comments on using the following handle_*_result functions are available
   in nsock_core.c */
/* handle_connect_results assumes that select or poll have already
   shown the descriptor to be active */
void handle_connect_result(mspool *ms, msevent *nse, 
                     enum nse_status status);

void handle_read_result(mspool *ms, msevent *nse, 
                  enum nse_status status);

void handle_write_result(mspool *ms, msevent *nse, 
                    enum nse_status status);

void handle_timer_result(mspool *ms, msevent *nse, 
                   enum nse_status status);

void nsock_trace(mspool *ms, char *fmt, ...)
     __attribute__ ((format (printf, 2, 3)));

/* An event has been completed and the handler is about to be called.  This function
   writes out tracing data about the event if neccessary */
void nsock_trace_handler_callback(mspool *ms, msevent *nse);

/* Returns the remote peer port (or -1 if unavailable).  Note the
   return value is a whole int so that -1 can be distinguished from
   65535.  Port is returned in host byte order. */
int nsi_peerport(msiod *nsi);

#if HAVE_OPENSSL
/* sets the ssl session of an nsock_iod, increments usage count.  The
 session should not have been set yet (as no freeing is done) */
void nsi_set_ssl_session(msiod *iod, SSL_SESSION *sessid);
#endif

#endif /* NSOCK_INTERNAL_H */










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