Follows, a patch that sets the time scale for NetXray v2
files based on the byte that's currently known as <hdr>.xxz[2].
It doesn't change anything for v1 files: those still switch
scale based on their minor version.
The byte and the scale they represent are based on some
some captures I have and e-mails and/or captures from
<pjw@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> and <jhouse@xxxxxxxxx>.
I picked xxz[2] since it's the sole unknown byte that varies
in a way that matches the reported times in the captures I
examined. Mind you, this is only a sample from three sites,
each running 3 different NAI sniffers.
Chris.
BTW, I'd previously said I suspected that xxz[3] encoded the
time scale for v2 files. That was wrong: the tool I wrote to
dig around in v2 headers labelled that byte "z3" and I guess
I made the obvious blunder when I wrote xxz[3].
Index: wiretap/netxray.c
===================================================================
RCS file: /cvsroot/ethereal/wiretap/netxray.c,v
retrieving revision 1.38
diff -u -r1.38 netxray.c
--- netxray.c 2001/03/23 23:16:29 1.38
+++ netxray.c 2001/05/08 23:33:19
@@ -50,7 +50,9 @@
guint32 end_offset; /* offset after last packet in capture */
guint32 xxy[3]; /* unknown */
guint16 network; /* datalink type */
- guint8 xxz[6];
+ guint8 xxz[2];
+ guint8 timeunit; /* encodes length of a tick */
+ guint8 xxa[3];
guint32 timelo; /* lower 32 bits of time stamp of capture start */
guint32 timehi; /* upper 32 bits of time stamp of capture start */
/*
@@ -58,6 +60,12 @@
*/
};
+/*
+ * # of ticks that equal 1 second
+ */
+static double TpS[] = { 1e6, 1193000.0, 1193180.0 };
+#define NUM_NETXRAY_TIMEUNITS (sizeof TpS / sizeof TpS[0])
+
/* Version number strings. */
static const char vers_1_0[] = {
'0', '0', '1', '.', '0', '0', '0', '\0'
@@ -167,7 +175,13 @@
file_type = WTAP_FILE_NETXRAY_1_1;
} else if (memcmp(hdr.version, vers_2_001, sizeof vers_2_001) == 0
|| memcmp(hdr.version, vers_2_002, sizeof vers_2_002) == 0) {
- timeunit = 1193180.0;
+ if (hdr.timeunit > NUM_NETXRAY_TIMEUNITS) {
+ g_message("netxray: Unknown timeunit %u",
+ hdr.timeunit);
+ *err = WTAP_ERR_UNSUPPORTED;
+ return -1;
+ }
+ timeunit = TpS[hdr.timeunit];
version_major = 2;
file_type = WTAP_FILE_NETXRAY_2_00x;
} else {
