From 50f76bf1834cc6a7c5c8560f63b8828d5177b7f4 Mon Sep 17 00:00:00 2001
From: angelos <angelos@openbsd.org>
Date: Sun, 27 Apr 1997 23:55:49 +0000
Subject: [PATCH] Random/unique NFS xids.

---
 sys/nfs/nfs_subs.c | 50 +++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/sys/nfs/nfs_subs.c b/sys/nfs/nfs_subs.c
index 3edd8a9d3a4..9906b699114 100644
--- a/sys/nfs/nfs_subs.c
+++ b/sys/nfs/nfs_subs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: nfs_subs.c,v 1.16 1997/04/25 09:30:14 deraadt Exp $	*/
+/*	$OpenBSD: nfs_subs.c,v 1.17 1997/04/27 23:55:49 angelos Exp $	*/
 /*	$NetBSD: nfs_subs.c,v 1.27.4.3 1996/07/08 20:34:24 jtc Exp $	*/
 
 /*
@@ -68,6 +68,7 @@
 #include <nfs/xdr_subs.h>
 #include <nfs/nfsm_subs.h>
 #include <nfs/nfsmount.h>
+#include <nfs/nfsrvcache.h>
 #include <nfs/nqnfs.h>
 #include <nfs/nfsrtt.h>
 #include <nfs/nfs_var.h>
@@ -81,12 +82,20 @@
 #include <netiso/iso.h>
 #endif
 
+#include <dev/rndvar.h>
+
 #ifdef __GNUC__
 #define INLINE __inline
 #else
 #define INLINE
 #endif
 
+#define NFSRCHASH(xid) \
+        (&nfsrvhashtbl[((xid) + ((xid) >> 24)) & nfsrvhash])
+extern LIST_HEAD(nfsrvhash, nfsrvcache) *nfsrvhashtbl;
+extern TAILQ_HEAD(nfsrvlru, nfsrvcache) nfsrvlruhead;
+extern u_long nfsrvhash;
+
 int	nfs_attrtimeo __P((struct nfsnode *np));
 
 /*
@@ -618,10 +627,9 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	register u_int32_t *tl;
 	register caddr_t bpos;
 	register int i;
+	register struct nfsrvcache *rp;
 	struct mbuf *mreq, *mb2;
 	int siz, grpsiz, authsiz;
-	struct timeval tv;
-	static u_int32_t base;
 
 	authsiz = nfsm_rndup(auth_len);
 	MGETHDR(mb, M_WAIT, MT_DATA);
@@ -641,21 +649,27 @@ nfsm_rpchead(cr, nmflag, procid, auth_type, auth_len, auth_str, verf_len,
 	 */
 	nfsm_build(tl, u_int32_t *, 8 * NFSX_UNSIGNED);
 
-	/*
-	 * derive initial xid from system time
-	 * XXX time is invalid if root not yet mounted
-	 */
-	if (!base && (rootvp)) {
-		microtime(&tv);
-		base = tv.tv_sec << 12;
-		nfs_xid = base;
-	}
-	/*
-	 * Skip zero xid if it should ever happen.
-	 */
-	if (++nfs_xid == 0)
-		nfs_xid++;
-
+	/* Get a new (non-zero) xid */
+
+	do
+	{
+	    i = 0;
+
+	    while (((*xidp = arc4random()) == nfs_xid) || (*xidp == 0))
+	      ;
+
+	    nfs_xid = *xidp;
+	    
+	    for (rp = NFSRCHASH(nfs_xid)->lh_first; rp !=0; 
+		 rp = rp->rc_hash.le_next)
+	      if ((nfs_xid == rp->rc_xid) &&
+		  (rp->rc_proc == procid))
+	      {
+		  i = 1;     /* do the loop again */
+		  break;
+	      }
+	} while (i);
+     
 	*tl++ = *xidp = txdr_unsigned(nfs_xid);
 	*tl++ = rpc_call;
 	*tl++ = rpc_vers;
-- 
2.20.1