infra: Clean up project setup

[tripe] / servutil.c

/* -*-c-*-
 *
 * $Id$
 *
 * Various handy server-only utilities
 *
 * (c) 2001 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"

/*----- Global variables --------------------------------------------------*/

octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];

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

/* --- @mpstr@ --- *
 *
 * Arguments:	@mp *m@ = a multiprecision integer
 *
 * Returns:	A pointer to the integer's textual representation.
 *
 * Use:		Converts a multiprecision integer to a string.  Corrupts
 *		@buf_t@.
 */

const char *mpstr(mp *m)
{
  if (mp_writestring(m, (char *)buf_t, sizeof(buf_t), 10))
    return ("<failed>");
  return ((const char *)buf_t);
}

/* --- @gestr@ --- *
 *
 * Arguments:	@group *g@ = a group
 *		@ge *x@ = a group element
 *
 * Returns:	A pointer to the element's textual representation.
 *
 * Use:		Converts a group element to a string.  Corrupts
 *		@buf_t@.
 */

const char *gestr(group *g, ge *x)
{
  if (group_writestring(g, x, (char *)buf_t, sizeof(buf_t)))
    return ("<failed>");
  return ((const char *)buf_t);
}

/* --- @timestr@ --- *
 *
 * Arguments:	@time_t t@ = a time to convert
 *
 * Returns:	A pointer to a textual representation of the time.
 *
 * Use:		Converts a time to a textual representation.  Corrupts
 *		@buf_t@.
 */

const char *timestr(time_t t)
{
  struct tm *tm;
  if (!t)
    return ("NEVER");
  tm = localtime(&t);
  strftime((char *)buf_t, sizeof(buf_t), "%Y-%m-%dT%H:%M:%S", tm);
  return ((const char *)buf_t);
}

/* --- @b64_encode@ --- *
 *
 * Arguments:	@const void *p@ = pointer to some gorp
 *		@size_t sz@ = size of the gorp
 *
 * Returns:	Pointer to base64-encoded version in @buf_t@.
 */

const char *b64_encode(const void *p, size_t sz)
{
  base64_ctx b64;
  dstr d = DSTR_INIT;

  base64_init(&b64);
  b64.indent = "";
  b64.maxline = 0;
  base64_encode(&b64, p, sz, &d);
  base64_encode(&b64, 0, 0, &d);
  while (d.len && d.buf[d.len - 1] == '=') d.len--;
  assert(d.len < sizeof(buf_t));
  memcpy(buf_t, d.buf, d.len);
  buf_t[d.len] = 0;
  dstr_destroy(&d);
  return ((const char *)buf_t);
}

/* --- @seq_reset@ --- *
 *
 * Arguments:	@seqwin *s@ = sequence-checking window
 *
 * Returns:	---
 *
 * Use:		Resets a sequence number window.
 */

void seq_reset(seqwin *s) { s->seq = 0; s->win = 0; }

/* --- @seq_check@ --- *
 *
 * Arguments:	@seqwin *s@ = sequence-checking window
 *		@uint32 q@ = sequence number to check
 *
 * Returns:	A @SEQ_@ code.
 *
 * Use:		Checks a sequence number against the window, updating things
 *		as necessary.
 */

int seq_check(seqwin *s, uint32 q)
{
  uint32 qbit;
  uint32 n;

  if (q < s->seq)
    return (SEQ_OLD);
  if (q >= s->seq + SEQ_WINSZ) {
    n = q - (s->seq + SEQ_WINSZ - 1);
    if (n < SEQ_WINSZ)
      s->win >>= n;
    else
      s->win = 0;
    s->seq += n;
  }
  qbit = 1 << (q - s->seq);
  if (s->win & qbit)
    return (SEQ_REPLAY);
  s->win |= qbit;
  return (0);
}

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