From cb2f54fd3ec011600ddda023b8f2d8ec5250bb8f Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 30 Mar 2020 18:12:00 +0100
Subject: [PATCH] Use CLOCK_MONOTONIC for all our timing needs, when possible

Otherwise we can malfunction if the clock warps.

This depends on an unreleased adns feature, so the warning is
currently not actually printed.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 configure    |  4 +---
 configure.ac |  2 +-
 resolver.c   |  3 +++
 secnet.c     | 10 ++++++++++
 4 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/configure b/configure
index 7cf4421..d076bd3 100755
--- a/configure
+++ b/configure
@@ -4250,9 +4250,7 @@ $as_echo "#define USE_MONOTONIC 1" >>confdefs.h
 
 else
 
-    { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Using non-monotonic clock, due to lack of adns_if_monotonic" >&5
-$as_echo "$as_me: WARNING: Using non-monotonic clock, due to lack of adns_if_monotonic" >&2;}
-
+:
 fi
 
 
diff --git a/configure.ac b/configure.ac
index 53810e4..aceed90 100644
--- a/configure.ac
+++ b/configure.ac
@@ -140,7 +140,7 @@ fi
 AC_CHECK_DECL([adns_if_monotonic],[
     AC_DEFINE([USE_MONOTONIC],[1],[Use CLOCK_MONOTONIC and adns_if_monotonic])
 ],[
-    AC_MSG_WARN([Using non-monotonic clock, due to lack of adns_if_monotonic])
+: dnl AC_MSG_WARN([Using non-monotonic clock, due to lack of adns_if_monotonic])
 ],[AC_INCLUDES_DEFAULT
 #include <adns.h>
 ])
diff --git a/resolver.c b/resolver.c
index 45738ea..3f9a6d5 100644
--- a/resolver.c
+++ b/resolver.c
@@ -211,6 +211,9 @@ static list_t *adnsresolver_apply(closure_t *self, struct cloc loc,
     conf=dict_read_string(d,"config",False,"adns",loc);
 
     adns_initflags iflags = 0;
+#if USE_MONOTONIC
+    iflags |= adns_if_monotonic;
+#endif
 
     if (conf) {
 	if (adns_init_strcfg(&st->ast, iflags, 0, conf)) {
diff --git a/secnet.c b/secnet.c
index e15ee81..177c2ef 100644
--- a/secnet.c
+++ b/secnet.c
@@ -24,6 +24,7 @@
 #include <string.h>
 #include <getopt.h>
 #include <errno.h>
+#include <time.h>
 #include <unistd.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
@@ -356,9 +357,18 @@ static void run(void)
     int allocdfds=0, shortfall=0;
 
     do {
+#if USE_MONOTONIC
+	struct timespec ts;
+	if (clock_gettime(CLOCK_MONOTONIC, &ts)!=0) {
+	    fatal_perror("main loop: clock_gettime(CLOCK_MONOTONIC,)");
+	}
+	tv_now_global.tv_sec =  ts.tv_sec;
+	tv_now_global.tv_usec = ts.tv_nsec / 1000;
+#else /* !USE_MONOTONIC */
 	if (gettimeofday(&tv_now_global, NULL)!=0) {
 	    fatal_perror("main loop: gettimeofday");
 	}
+#endif /* !USE_MONOTONIC */
 	now_global=((uint64_t)tv_now_global.tv_sec*(uint64_t)1000)+
 	           ((uint64_t)tv_now_global.tv_usec/(uint64_t)1000);
 	idx=0;
-- 
2.30.2