From 6cfff91d43885f60cbe30a7b237c69fcc85e31a2 Mon Sep 17 00:00:00 2001
From: Steve Reinhardt <steve.reinhardt@amd.com>
Date: Tue, 17 Feb 2009 19:24:46 -0800
Subject: [PATCH] Make etherdump timestamps zero-based. We previously used the
 actual wall time for the base timestamps, making etherdumps
 non-deterministic.  This fixes that problem and gets rid of the "malformed
 packet" at the front that we needed to provide the right base timestamp to
 wireshark/tcpdump.

---
 src/dev/etherdump.cc | 17 ++---------------
 src/dev/etherdump.hh |  2 --
 2 files changed, 2 insertions(+), 17 deletions(-)

diff --git a/src/dev/etherdump.cc b/src/dev/etherdump.cc
index 57da8a7f0..c41ce4e1f 100644
--- a/src/dev/etherdump.cc
+++ b/src/dev/etherdump.cc
@@ -75,31 +75,18 @@ struct pcap_pkthdr {
 void
 EtherDump::init()
 {
-    curtime = time(NULL);
     struct pcap_file_header hdr;
     hdr.magic = TCPDUMP_MAGIC;
     hdr.version_major = PCAP_VERSION_MAJOR;
     hdr.version_minor = PCAP_VERSION_MINOR;
 
-    hdr.thiszone = -5 * 3600;
+    hdr.thiszone = 0;
     hdr.snaplen = 1500;
     hdr.sigfigs = 0;
     hdr.linktype = DLT_EN10MB;
 
     stream->write(reinterpret_cast<char *>(&hdr), sizeof(hdr));
 
-    /*
-     * output an empty packet with the current time so that we know
-     * when the simulation began.  This allows us to correlate packets
-     * to sim_cycles.
-     */
-    pcap_pkthdr pkthdr;
-    pkthdr.seconds = curtime;
-    pkthdr.microseconds = 0;
-    pkthdr.caplen = 0;
-    pkthdr.len = 0;
-    stream->write(reinterpret_cast<char *>(&pkthdr), sizeof(pkthdr));
-
     stream->flush();
 }
 
@@ -107,7 +94,7 @@ void
 EtherDump::dumpPacket(EthPacketPtr &packet)
 {
     pcap_pkthdr pkthdr;
-    pkthdr.seconds = curtime + (curTick / Clock::Int::s);
+    pkthdr.seconds = curTick / Clock::Int::s;
     pkthdr.microseconds = (curTick / Clock::Int::us) % ULL(1000000);
     pkthdr.caplen = std::min(packet->length, maxlen);
     pkthdr.len = packet->length;
diff --git a/src/dev/etherdump.hh b/src/dev/etherdump.hh
index 733e61c97..18a5d2c44 100644
--- a/src/dev/etherdump.hh
+++ b/src/dev/etherdump.hh
@@ -51,8 +51,6 @@ class EtherDump : public SimObject
     void dumpPacket(EthPacketPtr &packet);
     void init();
 
-    Tick curtime;
-
   public:
     typedef EtherDumpParams Params;
     EtherDump(const Params *p);
-- 
2.30.2