/* SCTP kernel implementation
   * Copyright (c) 2003 International Business Machines, Corp.
   *
   * This file is part of the SCTP kernel implementation
   *
   * These functions manipulate sctp SSN tracker.
   *
   * This SCTP implementation 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, or (at your option)
   * any later version.
   *
   * This SCTP implementation 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 GNU CC; see the file COPYING.  If not, see
   * <http://www.gnu.org/licenses/>.
   *
   * Please send any bug reports or fixes you make to the
   * email address(es):
   *    lksctp developers <linux-sctp@vger.kernel.org>
   *
   * Written or modified by:
   *    Jon Grimm             <jgrimm@us.ibm.com>
   */
  
  #include <linux/types.h>
  #include <linux/slab.h>
  #include <net/sctp/sctp.h>
  #include <net/sctp/sm.h>
  
  static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  					    __u16 out);
  
  /* Storage size needed for map includes 2 headers and then the
   * specific needs of in or out streams.
   */
  static inline size_t sctp_ssnmap_size(__u16 in, __u16 out)
  {
  	return sizeof(struct sctp_ssnmap) + (in + out) * sizeof(__u16);
  }
  
  
  /* Create a new sctp_ssnmap.
   * Allocate room to store at least 'len' contiguous TSNs.
   */
  struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
  				    gfp_t gfp)
  {
  	struct sctp_ssnmap *retval;
  	int size;
  
  	size = sctp_ssnmap_size(in, out);
  	if (size <= KMALLOC_MAX_SIZE)
  		retval = kmalloc(size, gfp);
  	else
  		retval = (struct sctp_ssnmap *)
  			  __get_free_pages(gfp, get_order(size));
  	if (!retval)
  		goto fail;
  
  	if (!sctp_ssnmap_init(retval, in, out))
  		goto fail_map;
  
  	SCTP_DBG_OBJCNT_INC(ssnmap);
  
  	return retval;
  
  fail_map:
  	if (size <= KMALLOC_MAX_SIZE)
  		kfree(retval);
  	else
  		free_pages((unsigned long)retval, get_order(size));
  fail:
  	return NULL;
  }
  
  
  /* Initialize a block of memory as a ssnmap.  */
  static struct sctp_ssnmap *sctp_ssnmap_init(struct sctp_ssnmap *map, __u16 in,
  					    __u16 out)
  {
  	memset(map, 0x00, sctp_ssnmap_size(in, out));
  
  	/* Start 'in' stream just after the map header. */
  	map->in.ssn = (__u16 *)&map[1];
  	map->in.len = in;
  
  	/* Start 'out' stream just after 'in'. */
  	map->out.ssn = &map->in.ssn[in];
  	map->out.len = out;
  
  	return map;
  }
  
  /* Clear out the ssnmap streams.  */
  void sctp_ssnmap_clear(struct sctp_ssnmap *map)
  {
  	size_t size;
  
  	size = (map->in.len + map->out.len) * sizeof(__u16);
  	memset(map->in.ssn, 0x00, size);
  }
  
  /* Dispose of a ssnmap.  */
  void sctp_ssnmap_free(struct sctp_ssnmap *map)
  {
  	int size;
  
  	if (unlikely(!map))
  		return;
  
  	size = sctp_ssnmap_size(map->in.len, map->out.len);
  	if (size <= KMALLOC_MAX_SIZE)
  		kfree(map);
  	else
  		free_pages((unsigned long)map, get_order(size));
  
  	SCTP_DBG_OBJCNT_DEC(ssnmap);
  }