From ff2e5a2ada6196ce4ed89a76b5e86f047c9a63f4 Mon Sep 17 00:00:00 2001
From: Marius Tomaschewski <mt@suse.de>
Date: Wed, 12 Jan 2011 16:41:45 +0100
Subject: [PATCH] ip route rtt metrics time unit is milliseconds

Adopted ip route rtt,rttvar,rto_min metrics time unit to milliseconds
instead of jiffies as required by recent kernels (>=2.6.27).

Added an get_rtt_metrics_units function providing the unit and the
get_time_in_units as successor of get_jiffies function, allowing to
specify the unit. The get_rtt_metrics_units can be extended to detect
and handle also older kernels.

This fixes also the inconsistent use of get_user_hz in print_route
and get_hz in get_jiffies function that return different units.
---
 include/utils.h |    1 +
 ip/iproute.c    |   38 ++++++++++++++++++++++++++------------
 lib/utils.c     |   24 +++++++++++++-----------
 3 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/include/utils.h b/include/utils.h
index 3da6998..3d98c01 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -80,6 +80,7 @@ extern int mask2bits(__u32 netmask);
 extern int get_integer(int *val, const char *arg, int base);
 extern int get_unsigned(unsigned *val, const char *arg, int base);
 extern int get_jiffies(unsigned *val, const char *arg, int base, int *raw);
+extern int get_time_in_units(unsigned *val, const char *arg, int base, int *raw, unsigned unit);
 #define get_byte get_u8
 #define get_ushort get_u16
 #define get_short get_s16
diff --git a/ip/iproute.c b/ip/iproute.c
index 0d69290..830b0a3 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -33,6 +33,21 @@
 #define RTAX_RTTVAR RTAX_HOPS
 #endif
 
+#define TIME_UNIT_MS 1000
+
+static unsigned get_rtt_metrics_units(void)
+{
+	/*
+	 * recent kernels (>=2.6.27) are using milliseconds base.
+	 * Note: To support older kernels, return the proper HZ...
+	 *
+	 * final unit for rto_min: unit
+	 *                rttvar:  unit * 4
+	 *                rtt:     unit * 8
+	 */
+	return TIME_UNIT_MS;
+}
+
 enum list_action {
 	IPROUTE_LIST,
 	IPROUTE_FLUSH,
@@ -522,12 +537,11 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 			mxlock = *(unsigned*)RTA_DATA(mxrta[RTAX_LOCK]);
 
 		for (i=2; i<= RTAX_MAX; i++) {
-			unsigned val;
+			unsigned long long val; /* val *= 1000 below */
+			unsigned unit = get_rtt_metrics_units();
 
 			if (mxrta[i] == NULL)
 				continue;
-			if (!hz)
-				hz = get_user_hz();
 
 			if (i < sizeof(mx_names)/sizeof(char*) && mx_names[i])
 				fprintf(fp, " %s", mx_names[i]);
@@ -543,24 +557,24 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 					val = 0;
 				/* fall through */
 			default:
-				fprintf(fp, " %u", val);
+				fprintf(fp, " %llu", val);
 				break;
 
 			case RTAX_RTT:
 			case RTAX_RTTVAR:
 			case RTAX_RTO_MIN:
-				val *= 1000;
+				val *= TIME_UNIT_MS;
 				if (i == RTAX_RTT)
 					val /= 8;
 				else if (i == RTAX_RTTVAR)
 					val /= 4;
 
-				if (val >= hz)
+				if (val >= unit)
 					fprintf(fp, " %llums",
-						(unsigned long long) val / hz);
+						val / unit);
 				else
-					fprintf(fp, " %.2fms", 
-						(double)val / hz);
+					fprintf(fp, " %.8fms", 
+						(double)val / unit);
 			}
 		}
 	}
@@ -840,7 +854,7 @@ int iproute_modify(int cmd, unsigned flags, int argc, char **argv)
 				mxlock |= (1<<RTAX_RTT);
 				NEXT_ARG();
 			}
-			if (get_jiffies(&rtt, *argv, 0, &raw))
+			if (get_time_in_units(&rtt, *argv, 0, &raw, get_rtt_metrics_units()))
 				invarg("\"rtt\" value is invalid\n", *argv);
 			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_RTT, 
 				(raw) ? rtt : rtt * 8);
@@ -848,7 +862,7 @@ int iproute_modify(int cmd, unsigned flags, int argc, char **argv)
 			unsigned rto_min;
 			NEXT_ARG();
 			mxlock |= (1<<RTAX_RTO_MIN);
-			if (get_jiffies(&rto_min, *argv, 0, &raw))
+			if (get_time_in_units(&rto_min, *argv, 0, &raw, get_rtt_metrics_units()))
 				invarg("\"rto_min\" value is invalid\n",
 				       *argv);
 			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_RTO_MIN,
@@ -900,7 +914,7 @@ int iproute_modify(int cmd, unsigned flags, int argc, char **argv)
 				mxlock |= (1<<RTAX_RTTVAR);
 				NEXT_ARG();
 			}
-			if (get_jiffies(&win, *argv, 0, &raw))
+			if (get_time_in_units(&win, *argv, 0, &raw, get_rtt_metrics_units()))
 				invarg("\"rttvar\" value is invalid\n", *argv);
 			rta_addattr32(mxrta, sizeof(mxbuf), RTAX_RTTVAR,
 				(raw) ? win : win * 4);
diff --git a/lib/utils.c b/lib/utils.c
index a60d884..a21a2ae 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -102,6 +102,11 @@ int get_unsigned(unsigned *val, const char *arg, int base)
 
 int get_jiffies(unsigned *jiffies, const char *arg, int base, int *raw)
 {
+	return get_time_in_units(jiffies, arg, base, raw, get_hz());
+}
+
+int get_time_in_units(unsigned *val, const char *arg, int base, int *raw, unsigned unit)
+{
 	double t;
 	unsigned long res;
 	char *p;
@@ -120,37 +125,34 @@ int get_jiffies(unsigned *jiffies, const char *arg, int base, int *raw)
 	if (p == arg)
 		return -1;
 
-	if (__iproute2_hz_internal == 0)
-                __iproute2_hz_internal = __get_hz();
-	
 	*raw = 1;
 
 	if (*p) {
 		*raw = 0;
                 if (strcasecmp(p, "s") == 0 || strcasecmp(p, "sec")==0 ||
                     strcasecmp(p, "secs")==0)
-                        t *= __iproute2_hz_internal;
+                        t *= unit;
                 else if (strcasecmp(p, "ms") == 0 || strcasecmp(p, "msec")==0 ||
                          strcasecmp(p, "msecs") == 0)
-                        t *= __iproute2_hz_internal/1000.0;
+                        t *= unit/1000.0;
                 else if (strcasecmp(p, "us") == 0 || strcasecmp(p, "usec")==0 ||
                          strcasecmp(p, "usecs") == 0)
-                        t *= __iproute2_hz_internal/1000000.0;
+                        t *= unit/1000000.0;
                 else if (strcasecmp(p, "ns") == 0 || strcasecmp(p, "nsec")==0 ||
                          strcasecmp(p, "nsecs") == 0)
-                        t *= __iproute2_hz_internal/1000000000.0;
+                        t *= unit/1000000000.0;
 		else if (strcasecmp(p, "j") == 0 || strcasecmp(p, "hz") == 0 ||
 			 strcasecmp(p,"jiffies") == 0)
-			t *= 1.0; /* allow suffix, do nothing */
+			t *= unit/(double)get_hz();
                 else
                         return -1;
         }
 
 	/* emulate ceil() without having to bring-in -lm and always be >= 1 */
 
-	*jiffies = t;
-	if (*jiffies < t)
-		*jiffies += 1;
+	*val = t;
+	if (*val < t)
+		*val += 1;
 	
         return 0;
 
-- 
1.7.1