server: Introduce another temporary buffer for debugging output.

[tripe] / server / addrmap.c

/* -*-c-*-
 *
 * Hashtables keyed by network addresses
 *
 * (c) 2007 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Trivial IP Encryption (TrIPE).
 *
 * TrIPE 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.
 *
 * TrIPE 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 TrIPE; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include "tripe.h"

#define AM_LOAD(n) (((n) * 3)/2)

/*----- Main code ---------------------------------------------------------*/

/* --- @am_create@ --- *
 *
 * Arguments:	@addrmap *m@ = pointer to map
 *
 * Returns:	---
 *
 * Use:		Create an address map, properly set up.
 */

void am_create(addrmap *m)
{
  hash_create(&m->t, 16);
  m->load = AM_LOAD(m->t.mask + 1);
}

/* --- @am_destroy@ --- *
 *
 * Arguments:	@addrmap *m@ = pointer to map
 *
 * Returns:	---
 *
 * Use:		Destroy an address map, throwing away all the entries.
 */

void am_destroy(addrmap *m)
{
  hash_base *p;
  hash_iter i;

  for (hash_mkiter(&i, &m->t); (p = hash_next(&i)) != 0; )
    x_free(m->t.a, p);
  hash_destroy(&m->t);
}

/* --- @hash@ --- *
 *
 * Arguments:	@const addr *a@ = pointer to address
 *
 * Returns:	The hash of the address.
 */

uint32 hash(const addr *a)
{
  switch (a->sa.sa_family) {
    case AF_INET:
      return (U32((AF_INET * 0x4eaac1b7ul) +
		  (a->sin.sin_addr.s_addr * 0xa5dbc837) +
		  (a->sin.sin_port * 0x3b049e83)));
    default:
      abort();
  }
}

/* --- @addreq@ --- *
 *
 * Arguments:	@const addr *a, *b@ = pointer to addresses
 *
 * Returns:	Nonzero if the addresses are equal.
 */

int addreq(const addr *a, const addr *b)
{
  if (a->sa.sa_family != b->sa.sa_family)
    return (0);
  switch (a->sa.sa_family) {
    case AF_INET:
      return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr &&
	      a->sin.sin_port == b->sin.sin_port);
    default:
      abort();
  }
}

/* --- @am_find@ --- *
 *
 * Arguments:	@addrmap *m@ = pointer to map
 *		@const addr *a@ = address to look up
 *		@size_t sz@ = size of block to allocate
 *		@unsigned *f@ = where to store flags
 *
 * Returns:	Pointer to found item, or null.
 *
 * Use:		Finds a record with the given IP address, set @*f@ nonzero
 *		and returns it.  If @sz@ is zero, and no match was found,
 *		return null; otherwise allocate a new block of @sz@ bytes,
 *		clear @*f@ to zero and return the block pointer.
 */

void *am_find(addrmap *m, const addr *a, size_t sz, unsigned *f)
{
  uint32 h = hash(a);
  hash_base **b, **bb;
  addrmap_base *i;

  bb = HASH_BIN(&m->t, h);
  for (b = bb; *b; b = &(*b)->next) {
    i = (addrmap_base *)*b;
    if (i->b.hash == h && addreq(a, &i->a)) {
      *b = i->b.next;
      i->b.next = *bb;
      *bb = &i->b;
      if (f) *f = 1;
      return (i);
    }
  }

  if (f) *f = 0;
  if (!sz) return (0);
  i = x_alloc(m->t.a, sz);
  i->b.hash = h;
  i->b.next = *bb;
  *bb = &i->b;
  i->a = *a;

  if (m->load)
    m->load--;
  if (!m->load && hash_extend(&m->t))
    m->load = AM_LOAD(m->t.mask + 1);
  return (i);
}

/* --- @am_remove@ --- *
 *
 * Arguments:	@addrmap *m@ = pointer to map
 *		@void *i@ = pointer to the item
 *
 * Returns:	---
 *
 * Use:		Removes an item from the map.
 */

void am_remove(addrmap *m, void *i)
{
  hash_remove(&m->t, i);
  x_free(m->t.a, i);
}

/*----- That's all, folks -------------------------------------------------*/