svn commit: r361422 - head/sys/netinet/tcp_stacks

[Emmanuel Vadot]

Author: manu
Date: Sat May 23 19:52:20 2020
New Revision: 361422
URL: https://svnweb.freebsd.org/changeset/base/361422

Log:
  bbr: Use arc4random_uniform from libkern.
  
  This unbreak LINT build
  
  Reported by:	jenkins, melifaro

Modified:
  head/sys/netinet/tcp_stacks/bbr.c

Modified: head/sys/netinet/tcp_stacks/bbr.c
==============================================================================
--- head/sys/netinet/tcp_stacks/bbr.c	Sat May 23 19:06:57 2020	(r361421)
+++ head/sys/netinet/tcp_stacks/bbr.c	Sat May 23 19:52:20 2020	(r361422)
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/arb.h>
 #include <sys/module.h>
 #include <sys/kernel.h>
+#include <sys/libkern.h>
 #ifdef TCP_HHOOK
 #include <sys/hhook.h>
 #endif
@@ -3095,43 +3096,6 @@ bbr_lt_bw_samp_done(struct tcp_bbr *bbr, uint64_t bw, 
 	bbr->r_ctl.rc_lt_bw = bw;
 	bbr_reset_lt_bw_interval(bbr, cts);
 	bbr_log_type_ltbw(bbr, cts, 5, 0, (uint32_t)bw, 0, timin);
-}
-
-/*
- * RRS: Copied from user space!
- * Calculate a uniformly distributed random number less than upper_bound
- * avoiding "modulo bias".
- *
- * Uniformity is achieved by generating new random numbers until the one
- * returned is outside the range [0, 2**32 % upper_bound).  This
- * guarantees the selected random number will be inside
- * [2**32 % upper_bound, 2**32) which maps back to [0, upper_bound)
- * after reduction modulo upper_bound.
- */
-static uint32_t
-arc4random_uniform(uint32_t upper_bound)
-{
-	uint32_t r, min;
-
-	if (upper_bound < 2)
-		return 0;
-
-	/* 2**32 % x == (2**32 - x) % x */
-	min = -upper_bound % upper_bound;
-
-	/*
-	 * This could theoretically loop forever but each retry has
-	 * p > 0.5 (worst case, usually far better) of selecting a
-	 * number inside the range we need, so it should rarely need
-	 * to re-roll.
-	 */
-	for (;;) {
-		r = arc4random();
-		if (r >= min)
-			break;
-	}
-
-	return r % upper_bound;
 }
 
 static void