X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/blobdiff_plain/a7880467f330b9824be66934fc5cb00508bf0229..042d5c20a1c42002b35aa13c7a44dfb4a94d2e65:/servutil.c

diff --git a/servutil.c b/servutil.c
index 2c5f3d83..92a5f775 100644
--- a/servutil.c
+++ b/servutil.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: servutil.c,v 1.2 2001/02/16 21:41:06 mdw Exp $
+ * $Id$
  *
  * Various handy server-only utilities
  *
@@ -26,22 +26,14 @@
  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: servutil.c,v $
- * Revision 1.2  2001/02/16 21:41:06  mdw
- * Use new spare buffer for building MP textual representations.  Add a
- * function for making human-readable time strings.
- *
- * Revision 1.1  2001/02/03 20:26:37  mdw
- * Initial checkin.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include "tripe.h"
 
+/*----- Global variables --------------------------------------------------*/
+
+octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ];
+
 /*----- Main code ---------------------------------------------------------*/
 
 /* --- @mpstr@ --- *
@@ -61,6 +53,24 @@ const char *mpstr(mp *m)
   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
@@ -81,4 +91,53 @@ const char *timestr(time_t t)
   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
+ *		@const char *service@ = service to report message from
+ *
+ * Returns:	Zero on success, nonzero if the sequence number was bad.
+ *
+ * Use:		Checks a sequence number against the window, updating things
+ *		as necessary.
+ */
+
+int seq_check(seqwin *s, uint32 q, const char *service)
+{
+  uint32 qbit;
+  uint32 n;
+
+  if (q < s->seq) {
+    a_warn(service, "replay", "old-sequence", A_END);
+    return (-1);
+  }
+  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) {
+    a_warn(service, "replay", "duplicated-sequence", A_END);
+    return (-1);
+  }
+  s->win |= qbit;
+  return (0);
+}
+
 /*----- That's all, folks -------------------------------------------------*/