From 65e42f87fe945a2bf30d7e02358554dbaefa8a4c Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Fri, 24 Sep 2010 22:15:11 +1000
Subject:    - djm@cvs.openbsd.org 2010/09/22 22:58:51      [atomicio.c
 atomicio.h misc.c misc.h scp.c sftp-client.c]      [sftp-client.h sftp.1
 sftp.c]      add an option per-read/write callback to atomicio

     factor out bandwidth limiting code from scp(1) into a generic bandwidth
     limiter that can be attached using the atomicio callback mechanism

     add a bandwidth limit option to sftp(1) using the above
     "very nice" markus@
---
 misc.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 65 insertions(+), 1 deletion(-)

(limited to 'misc.c')

diff --git a/misc.c b/misc.c
index a82e7936e..41c92a82b 100644
--- a/misc.c
+++ b/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.80 2010/07/21 02:10:58 djm Exp $ */
+/* $OpenBSD: misc.c,v 1.81 2010/09/22 22:58:51 djm Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -860,6 +860,70 @@ timingsafe_bcmp(const void *b1, const void *b2, size_t n)
 		ret |= *p1++ ^ *p2++;
 	return (ret != 0);
 }
+
+void
+bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
+{
+	bw->buflen = buflen;
+	bw->rate = kbps;
+	bw->thresh = bw->rate;
+	bw->lamt = 0;
+	timerclear(&bw->bwstart);
+	timerclear(&bw->bwend);
+}	
+
+/* Callback from read/write loop to insert bandwidth-limiting delays */
+void
+bandwidth_limit(struct bwlimit *bw, size_t read_len)
+{
+	u_int64_t waitlen;
+	struct timespec ts, rm;
+
+	if (!timerisset(&bw->bwstart)) {
+		gettimeofday(&bw->bwstart, NULL);
+		return;
+	}
+
+	bw->lamt += read_len;
+	if (bw->lamt < bw->thresh)
+		return;
+
+	gettimeofday(&bw->bwend, NULL);
+	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
+	if (!timerisset(&bw->bwend))
+		return;
+
+	bw->lamt *= 8;
+	waitlen = (double)1000000L * bw->lamt / bw->rate;
+
+	bw->bwstart.tv_sec = waitlen / 1000000L;
+	bw->bwstart.tv_usec = waitlen % 1000000L;
+
+	if (timercmp(&bw->bwstart, &bw->bwend, >)) {
+		timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
+
+		/* Adjust the wait time */
+		if (bw->bwend.tv_sec) {
+			bw->thresh /= 2;
+			if (bw->thresh < bw->buflen / 4)
+				bw->thresh = bw->buflen / 4;
+		} else if (bw->bwend.tv_usec < 10000) {
+			bw->thresh *= 2;
+			if (bw->thresh > bw->buflen * 8)
+				bw->thresh = bw->buflen * 8;
+		}
+
+		TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
+		while (nanosleep(&ts, &rm) == -1) {
+			if (errno != EINTR)
+				break;
+			ts = rm;
+		}
+	}
+
+	bw->lamt = 0;
+	gettimeofday(&bw->bwstart, NULL);
+}
 void
 sock_set_v6only(int s)
 {
-- 
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