From d6d34f3a1fc11546a88f457a42e136a22d1e37b0 Mon Sep 17 00:00:00 2001
From: Jon Siwek <jsiwek@ncsa.illinois.edu>
Date: Mon, 1 Aug 2011 16:25:27 -0500
Subject: [PATCH] Fix PktSrc::Statistics returning bogus stats.

When reading from trace files, 'dropped' and 'link' fields are now
just zeroed.

When reading from an interface, the values filled in by pcap_stats()
are now only used when that function indicates success.

Closes #500.
---
 src/PktSrc.cc                                 | 22 ++++++++++++-------
 .../Baseline/bifs.net_stats_trace/output      |  1 +
 testing/btest/bifs/net_stats_trace.test       |  8 +++++++
 3 files changed, 23 insertions(+), 8 deletions(-)
 create mode 100644 testing/btest/Baseline/bifs.net_stats_trace/output
 create mode 100644 testing/btest/bifs/net_stats_trace.test

diff --git a/src/PktSrc.cc b/src/PktSrc.cc
index b2287bf8e8..23391c1ffa 100644
--- a/src/PktSrc.cc
+++ b/src/PktSrc.cc
@@ -393,21 +393,27 @@ void PktSrc::AddSecondaryTablePrograms()
 
 void PktSrc::Statistics(Stats* s)
 	{
-	struct pcap_stat pstat;
-
 	if ( reading_traces )
 		s->received = s->dropped = s->link = 0;
 
-	else if ( pcap_stats(pd, &pstat) < 0 )
+	else
 		{
-		reporter->Error("problem getting packet filter statistics: %s",
-				ErrorMsg());
-		s->received = s->dropped = s->link = 0;
+		struct pcap_stat pstat;
+		if ( pcap_stats(pd, &pstat) < 0 )
+			{
+			reporter->Error("problem getting packet filter statistics: %s",
+					ErrorMsg());
+			s->received = s->dropped = s->link = 0;
+			}
+
+		else
+			{
+			s->dropped = pstat.ps_drop;
+			s->link = pstat.ps_recv;
+			}
 		}
 
 	s->received = stats.received;
-	s->dropped = pstat.ps_drop;
-	s->link = pstat.ps_recv;
 
 	if ( pseudo_realtime )
 		s->dropped = 0;
diff --git a/testing/btest/Baseline/bifs.net_stats_trace/output b/testing/btest/Baseline/bifs.net_stats_trace/output
new file mode 100644
index 0000000000..a2e25e03a7
--- /dev/null
+++ b/testing/btest/Baseline/bifs.net_stats_trace/output
@@ -0,0 +1 @@
+[pkts_recvd=131, pkts_dropped=0, pkts_link=0]
diff --git a/testing/btest/bifs/net_stats_trace.test b/testing/btest/bifs/net_stats_trace.test
new file mode 100644
index 0000000000..fcf3e9ba0d
--- /dev/null
+++ b/testing/btest/bifs/net_stats_trace.test
@@ -0,0 +1,8 @@
+# Checks that accurate stats are returned when reading from a trace file.
+# @TEST-EXEC: bro -r $TRACES/wikipedia.trace >output %INPUT
+# @TEST-EXEC: btest-diff output
+
+event bro_done()
+	{
+	print net_stats();
+	}