mdw@git.distorted.org.uk Git - tripe/blob - server/servutil.c

   1 /* -*-c-*-
   2  *
   3  * Various handy server-only utilities
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Trivial IP Encryption (TrIPE).
  11  *
  12  * TrIPE is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 /*----- Header files ------------------------------------------------------*/
  28
  29 #include "tripe.h"
  30
  31 /*----- Global variables --------------------------------------------------*/
  32
  33 octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ], buf_u[PKBUFSZ];
  34
  35 /*----- Main code ---------------------------------------------------------*/
  36
  37 /* --- @mpstr@ --- *
  38  *
  39  * Arguments:   @mp *m@ = a multiprecision integer
  40  *
  41  * Returns:     A pointer to the integer's textual representation.
  42  *
  43  * Use:         Converts a multiprecision integer to a string.  Corrupts
  44  *              @buf_u@.
  45  */
  46
  47 const char *mpstr(mp *m)
  48 {
  49   if (mp_writestring(m, (char *)buf_u, sizeof(buf_u), 10))
  50     return ("<failed>");
  51   return ((const char *)buf_u);
  52 }
  53
  54 /* --- @gestr@ --- *
  55  *
  56  * Arguments:   @group *g@ = a group
  57  *              @ge *x@ = a group element
  58  *
  59  * Returns:     A pointer to the element's textual representation.
  60  *
  61  * Use:         Converts a group element to a string.  Corrupts
  62  *              @buf_u@.
  63  */
  64
  65 const char *gestr(group *g, ge *x)
  66 {
  67   if (group_writestring(g, x, (char *)buf_u, sizeof(buf_u)))
  68     return ("<failed>");
  69   return ((const char *)buf_u);
  70 }
  71
  72 /* --- @timestr@ --- *
  73  *
  74  * Arguments:   @time_t t@ = a time to convert
  75  *
  76  * Returns:     A pointer to a textual representation of the time.
  77  *
  78  * Use:         Converts a time to a textual representation.  Corrupts
  79  *              @buf_u@.
  80  */
  81
  82 const char *timestr(time_t t)
  83 {
  84   struct tm *tm;
  85   if (!t)
  86     return ("NEVER");
  87   tm = localtime(&t);
  88   strftime((char *)buf_u, sizeof(buf_u), "%Y-%m-%dT%H:%M:%S", tm);
  89   return ((const char *)buf_u);
  90 }
  91
  92 /* --- @mystrieq@ --- *
  93  *
  94  * Arguments:   @const char *x, *y@ = two strings
  95  *
  96  * Returns:     True if @x@ and @y are equal, up to case.
  97  */
  98
  99 int mystrieq(const char *x, const char *y)
 100 {
 101   for (;;) {
 102     if (!*x && !*y) return (1);
 103     if (tolower((unsigned char)*x) != tolower((unsigned char)*y))
 104       return (0);
 105     x++; y++;
 106   }
 107 }
 108
 109 /* --- @seq_reset@ --- *
 110  *
 111  * Arguments:   @seqwin *s@ = sequence-checking window
 112  *
 113  * Returns:     ---
 114  *
 115  * Use:         Resets a sequence number window.
 116  */
 117
 118 void seq_reset(seqwin *s) { s->seq = 0; s->win = 0; }
 119
 120 /* --- @seq_check@ --- *
 121  *
 122  * Arguments:   @seqwin *s@ = sequence-checking window
 123  *              @uint32 q@ = sequence number to check
 124  *              @const char *service@ = service to report message from
 125  *
 126  * Returns:     Zero on success, nonzero if the sequence number was bad.
 127  *
 128  * Use:         Checks a sequence number against the window, updating things
 129  *              as necessary.
 130  */
 131
 132 int seq_check(seqwin *s, uint32 q, const char *service)
 133 {
 134   uint32 qbit;
 135   uint32 n;
 136
 137   if (q < s->seq) {
 138     a_warn(service, "replay", "old-sequence", A_END);
 139     return (-1);
 140   }
 141   if (q >= s->seq + SEQ_WINSZ) {
 142     n = q - (s->seq + SEQ_WINSZ - 1);
 143     if (n < SEQ_WINSZ)
 144       s->win >>= n;
 145     else
 146       s->win = 0;
 147     s->seq += n;
 148   }
 149   qbit = 1 << (q - s->seq);
 150   if (s->win & qbit) {
 151     a_warn(service, "replay", "duplicated-sequence", A_END);
 152     return (-1);
 153   }
 154   s->win |= qbit;
 155   return (0);
 156 }
 157
 158 /*----- That's all, folks -------------------------------------------------*/