On Mon, Aug 02, 1999 at 11:26:40PM -0700, Guy Harris wrote:
> Here's a patch to the current CVS tree, which adds "xdlc.c and
> "xdlc.h" files; "xdlc.c" defines a routine "dissect_xdlc_control()" to
> dissect the control field of a frame in an SDLC-derived protocol
> (although there may be some places where the processing has to be
> protocol-dependent).
>
> I modified "packet-llc.c" and "packet-lapb.c" to use it; it creates a
> subtree for the control field, giving a bitfield decode if you open up
> the subtree. It *should* handle both basic and extended mode - its
> caller passes in an argument to specify which mode it is (although I
> guess they should pass in a pointer to that flag, and it should set
> that flag if it sees one of the Set XXX Mode Extended commands;
> there'd still be a need to set it from outside, though, as you might
> not have that command in the capture).
>
> Olivier, feel free to change it; the only frames I deal with that have
> SDLC-derived protocols in them are FDDI and 802.3 frames, and I'm not
> sure I've seen any one other than a Boring Old Unnumbered Information
> field. I'm not checking it in, so that people can review it first (so
> if you want changes, tell me what you want changed, or send in a patch
> to do the change).
Here is a small patch against your modified tree. It seems to work well
for me, but my captures only contain Receive Ready and Information
frames (I included shifting in decode_numeric_bitfield ; you may want to
remove it...).
diff -uNr ethereal.xdlc2/packet-lapb.c ethereal.xdlc/packet-lapb.c
--- ethereal.xdlc2/packet-lapb.c Tue Aug 3 11:07:15 1999
+++ ethereal.xdlc/packet-lapb.c Tue Aug 3 10:57:42 1999
@@ -82,7 +82,7 @@
else
lapb_tree = NULL;
dissect_xdlc_control(pd, 1, fd, lapb_tree, hf_lapb_control,
- is_response, FALSE);
+ FALSE, is_response);
/* not end of frame ==> X.25 */
if (fd->cap_len > 2) dissect_x25(pd, 2, fd, tree);
diff -uNr ethereal.xdlc2/packet.c ethereal.xdlc/packet.c
--- ethereal.xdlc2/packet.c Tue Aug 3 11:07:19 1999
+++ ethereal.xdlc/packet.c Tue Aug 3 09:59:27 1999
@@ -530,12 +530,9 @@
{
static char buf[1025];
char *p;
- int shift=0;
-
- while ((mask & (1<<shift)) == 0) shift++;
p = decode_bitfield_value(buf, val, mask, width);
- sprintf(p, fmt, (val & mask) >> shift);
+ sprintf(p, fmt, val & mask);
return buf;
}
diff -uNr ethereal.xdlc2/xdlc.c ethereal.xdlc/xdlc.c
--- ethereal.xdlc2/xdlc.c Tue Aug 3 11:07:28 1999
+++ ethereal.xdlc/xdlc.c Tue Aug 3 10:57:42 1999
@@ -183,15 +183,15 @@
break;
}
if (is_extended) {
- sprintf(info, "S%s, %sN(R) = %u", frame_type,
+ sprintf(info, "S%s, func = %s, N(R) = %u", frame_type,
((control & XDLC_P_F_EXT) ?
- (is_response ? "func = F, " : "func = P, ") :
+ (is_response ? " F" : " P") :
""),
(control & XDLC_N_R_EXT_MASK) >> XDLC_N_R_EXT_SHIFT);
} else {
- sprintf(info, "S%s, %sN(R) = %u", frame_type,
+ sprintf(info, "S%s, func = %s, N(R) = %u", frame_type,
((control & XDLC_P_F) ?
- (is_response ? "func = F, " : "func = P, ") :
+ (is_response ? " F" : " P") :
""),
(control & XDLC_N_R_MASK) >> XDLC_N_R_SHIFT);
}
--
The number of arguments is unimportant unless some of them are correct.
-- Ralph Hartley
