michael@0: /*
michael@0:  * rdbx.h
michael@0:  *
michael@0:  * replay database with extended packet indices, using a rollover counter
michael@0:  *
michael@0:  * David A. McGrew
michael@0:  * Cisco Systems, Inc.
michael@0:  *
michael@0:  */
michael@0: /*
michael@0:  *	
michael@0:  * Copyright (c) 2001-2006, Cisco Systems, Inc.
michael@0:  * All rights reserved.
michael@0:  * 
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 
michael@0:  *   Redistributions of source code must retain the above copyright
michael@0:  *   notice, this list of conditions and the following disclaimer.
michael@0:  * 
michael@0:  *   Redistributions in binary form must reproduce the above
michael@0:  *   copyright notice, this list of conditions and the following
michael@0:  *   disclaimer in the documentation and/or other materials provided
michael@0:  *   with the distribution.
michael@0:  * 
michael@0:  *   Neither the name of the Cisco Systems, Inc. nor the names of its
michael@0:  *   contributors may be used to endorse or promote products derived
michael@0:  *   from this software without specific prior written permission.
michael@0:  * 
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0:  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0:  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
michael@0:  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
michael@0:  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
michael@0:  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
michael@0:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
michael@0:  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
michael@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
michael@0:  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
michael@0:  * OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: #ifndef RDBX_H
michael@0: #define RDBX_H
michael@0: 
michael@0: #include "datatypes.h"
michael@0: #include "err.h"
michael@0: 
michael@0: /* #define ROC_TEST */  
michael@0: 
michael@0: #ifndef ROC_TEST
michael@0: 
michael@0: typedef uint16_t sequence_number_t;   /* 16 bit sequence number  */
michael@0: typedef uint32_t rollover_counter_t;   /* 32 bit rollover counter */
michael@0: 
michael@0: #else  /* use small seq_num and roc datatypes for testing purposes */
michael@0: 
michael@0: typedef unsigned char sequence_number_t;         /* 8 bit sequence number   */
michael@0: typedef uint16_t rollover_counter_t;   /* 16 bit rollover counter */
michael@0: 
michael@0: #endif
michael@0: 
michael@0: #define seq_num_median (1 << (8*sizeof(sequence_number_t) - 1))
michael@0: #define seq_num_max    (1 << (8*sizeof(sequence_number_t)))
michael@0: 
michael@0: /*
michael@0:  * An xtd_seq_num_t is a 64-bit unsigned integer used as an 'extended'
michael@0:  * sequence number.  
michael@0:  */
michael@0: 
michael@0: typedef uint64_t xtd_seq_num_t;
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * An rdbx_t is a replay database with extended range; it uses an
michael@0:  * xtd_seq_num_t and a bitmask of recently received indices.
michael@0:  */
michael@0: 
michael@0: typedef struct {
michael@0:   xtd_seq_num_t index;
michael@0:   bitvector_t bitmask;
michael@0: } rdbx_t;
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * rdbx_init(rdbx_ptr, ws)
michael@0:  *
michael@0:  * initializes the rdbx pointed to by its argument with the window size ws,
michael@0:  * setting the rollover counter and sequence number to zero
michael@0:  */
michael@0: 
michael@0: err_status_t
michael@0: rdbx_init(rdbx_t *rdbx, unsigned long ws);
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * rdbx_dealloc(rdbx_ptr)
michael@0:  *
michael@0:  * frees memory associated with the rdbx
michael@0:  */
michael@0: 
michael@0: err_status_t
michael@0: rdbx_dealloc(rdbx_t *rdbx);
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * rdbx_estimate_index(rdbx, guess, s)
michael@0:  * 
michael@0:  * given an rdbx and a sequence number s (from a newly arrived packet),
michael@0:  * sets the contents of *guess to contain the best guess of the packet
michael@0:  * index to which s corresponds, and returns the difference between
michael@0:  * *guess and the locally stored synch info
michael@0:  */
michael@0: 
michael@0: int
michael@0: rdbx_estimate_index(const rdbx_t *rdbx,
michael@0: 		    xtd_seq_num_t *guess,
michael@0: 		    sequence_number_t s);
michael@0: 
michael@0: /*
michael@0:  * rdbx_check(rdbx, delta);
michael@0:  *
michael@0:  * rdbx_check(&r, delta) checks to see if the xtd_seq_num_t
michael@0:  * which is at rdbx->window_start + delta is in the rdb
michael@0:  *
michael@0:  */
michael@0: 
michael@0: err_status_t
michael@0: rdbx_check(const rdbx_t *rdbx, int difference);
michael@0: 
michael@0: /*
michael@0:  * replay_add_index(rdbx, delta)
michael@0:  * 
michael@0:  * adds the xtd_seq_num_t at rdbx->window_start + delta to replay_db
michael@0:  * (and does *not* check if that xtd_seq_num_t appears in db)
michael@0:  *
michael@0:  * this function should be called *only* after replay_check has
michael@0:  * indicated that the index does not appear in the rdbx, and a mutex
michael@0:  * should protect the rdbx between these calls if necessary.
michael@0:  */
michael@0: 
michael@0: err_status_t
michael@0: rdbx_add_index(rdbx_t *rdbx, int delta);
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * rdbx_set_roc(rdbx, roc) initalizes the rdbx_t at the location rdbx
michael@0:  * to have the rollover counter value roc.  If that value is less than
michael@0:  * the current rollover counter value, then the function returns
michael@0:  * err_status_replay_old; otherwise, err_status_ok is returned.
michael@0:  * 
michael@0:  */
michael@0: 
michael@0: err_status_t
michael@0: rdbx_set_roc(rdbx_t *rdbx, uint32_t roc);
michael@0: 
michael@0: /*
michael@0:  * rdbx_get_roc(rdbx) returns the value of the rollover counter for
michael@0:  * the rdbx_t pointed to by rdbx
michael@0:  * 
michael@0:  */
michael@0: 
michael@0: xtd_seq_num_t
michael@0: rdbx_get_packet_index(const rdbx_t *rdbx);
michael@0: 
michael@0: /*
michael@0:  * xtd_seq_num_t functions - these are *internal* functions of rdbx, and
michael@0:  * shouldn't be used to manipulate rdbx internal values.  use the rdbx
michael@0:  * api instead!
michael@0:  */
michael@0: 
michael@0: /*
michael@0:  * rdbx_get_ws(rdbx_ptr)
michael@0:  *
michael@0:  * gets the window size which was used to initialize the rdbx
michael@0:  */
michael@0: 
michael@0: unsigned long
michael@0: rdbx_get_window_size(const rdbx_t *rdbx);
michael@0: 
michael@0: 
michael@0: /* index_init(&pi) initializes a packet index pi (sets it to zero) */
michael@0: 
michael@0: void
michael@0: index_init(xtd_seq_num_t *pi);
michael@0: 
michael@0: /* index_advance(&pi, s) advances a xtd_seq_num_t forward by s */
michael@0: 
michael@0: void
michael@0: index_advance(xtd_seq_num_t *pi, sequence_number_t s);
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * index_guess(local, guess, s)
michael@0:  * 
michael@0:  * given a xtd_seq_num_t local (which represents the highest
michael@0:  * known-to-be-good index) and a sequence number s (from a newly
michael@0:  * arrived packet), sets the contents of *guess to contain the best
michael@0:  * guess of the packet index to which s corresponds, and returns the
michael@0:  * difference between *guess and *local
michael@0:  */
michael@0: 
michael@0: int
michael@0: index_guess(const xtd_seq_num_t *local,
michael@0: 		   xtd_seq_num_t *guess,
michael@0: 		   sequence_number_t s);
michael@0: 
michael@0: 
michael@0: #endif /* RDBX_H */
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0: 
michael@0: