- 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@

1 files changed, 65 insertions, 1 deletions

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)
 {