Wireshark · Ethereal-dev: [ethereal-dev] Update for packet-v120.c

[Bert Driehuis <driehuis@xxxxxxxxxxxxx>]

I never expected my first cut to hit the tree in 24 hours after posting!
You guys are *fast*!

By the way, writing the thing wasn't half as heard as I thought. A tribute
to the design principle that any decent programmer should be able to pick
it up!

The attached diff implements unpacking the H octet(s). I also took the
opportunity to fix my brain fart in the byte order of the address field;
since the bits are interpreted from right to left the bytes should follow
that order as well. The diff is relative to current CVS.

To answer some older questions, remarks and concerns:

 - 555-1212, in my recollection, is indeed the directory assistence number
that at least some carriers use in the US. In its original place of course
was the access number of my company's Portmaster 3. I rarely send packet
traces to public forums without taking access numbers (I also try to think
of passwords :-)  Incidentally, I think an ancient convenant between the
motion picture industry and the phone company (yes, that old) dictates
that all number used in motion pictures are of the form 555-xxxx.

 - My query about Q.931 actually presumed the differences I saw between
Ethereal and i4btrace stemmed from differences between implementations.
Given the history lesson Guy gave, it is quite possible that the stuff I
saw just points to unimplemented bits. When I get really bored I'll try to
implement as much as possible from EuroISDN in packet-q931.c as possible
without clashing with national ISDN. I cannot a priori preclude the
possibility that they use the same Q.931!

 - Some of my mail clients send an "Accept-Language: tr" header just
because a long time ago I got fed up with web sites second guessing my
language from my domain name, and the language setting from the browser
seems to creep into the mail client.

 - Yes, V.120 for isdn4bsd is coming along nicely now. I just had an
entire session using it, and my machine didn't crash until I tried to
reconnect without an intervening reboot! This makes my driver as good as
the Windows drivers I've seen so far.

'nuf rambling.

Cheers,

					-- Bert

Bert Driehuis, MIS -- bert_driehuis@xxxxxxxxxxxxxxxx -- +31-20-3116119
Hi! I'm a signature virus! Copy me to your .signature and help me spread!

*** packet-v120.c	Mon Dec 13 00:08:20 1999
--- /work/bertd/build/gnome/ethereal-0.7.9/packet-v120.c	Tue Dec 14 01:17:51 1999
***************
*** 3,7 ****
   * Bert Driehuis <driehuis@xxxxxxxxxxxxx>
   *
!  * $Id: packet-v120.c,v 1.2 1999/12/12 23:08:20 guy Exp $
   *
   * Ethereal - Network traffic analyzer
--- 3,7 ----
   * Bert Driehuis <driehuis@xxxxxxxxxxxxx>
   *
!  * $Id: $
   *
   * Ethereal - Network traffic analyzer
***************
*** 44,51 ****
--- 44,55 ----
  static int hf_v120_address = -1;
  static int hf_v120_control = -1;
+ static int hf_v120_header = -1;
  
  static gint ett_v120 = -1;
  static gint ett_v120_address = -1;
  static gint ett_v120_control = -1;
+ static gint ett_v120_header = -1;
+ 
+ void dissect_v120_header(const u_char *pd, int offset, frame_data *fd, proto_tree *tree);
  
  void
***************
*** 100,104 ****
  					    "V.120");
  	v120_tree = proto_item_add_subtree(ti, ett_v120);
! 	addr = pd[0] << 8 | pd[1];
  	sprintf(info, "LLI: %d C/R: %s",
  			((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1),
--- 104,108 ----
  					    "V.120");
  	v120_tree = proto_item_add_subtree(ti, ett_v120);
! 	addr = pd[1] << 8 | pd[0];
  	sprintf(info, "LLI: %d C/R: %s",
  			((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1),
***************
*** 106,135 ****
  	tc = proto_tree_add_item_format(v120_tree, ett_v120_address,
  			0, 2,
! 			"Address field: %s (0x%02X)", info, addr);
  	address_tree = proto_item_add_subtree(tc, ett_v120_address);
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x0200, 2*8,
  			"Response", "Command"), NULL);
  	sprintf(info, "LLI: %d", ((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1));
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_numeric_bitfield(addr, 0xfcfe, 2*8, info));
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x0100, 2*8,
  			"EA0 = 1 (Error)", "EA0 = 0"), NULL);
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x01, 2*8,
  			"EA1 = 1", "EA1 = 0 (Error)"), NULL);
! 	/* TODO: parse octets 4 & 5. Not that they're used in
! 	   practice, but it looks so professional. */
      }
      else
!         v120_tree = NULL;
      dissect_xdlc_control(pd, 2, fd, v120_tree, hf_v120_control,
  	    ett_v120_control, is_response, v120len == 3 ? FALSE : TRUE);
- 
-     /* not end of frame ==> X.25 */
  }
  
  void
  proto_register_v120(void)
  {
--- 110,189 ----
  	tc = proto_tree_add_item_format(v120_tree, ett_v120_address,
  			0, 2,
! 			"Address field: %s", info);
  	address_tree = proto_item_add_subtree(tc, ett_v120_address);
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x0002, 2*8,
  			"Response", "Command"), NULL);
  	sprintf(info, "LLI: %d", ((pd[0] & 0xfc) << 5) | ((pd[1] & 0xfe) >> 1));
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_numeric_bitfield(addr, 0xfefc, 2*8, info));
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x0001, 2*8,
  			"EA0 = 1 (Error)", "EA0 = 0"), NULL);
  	proto_tree_add_text(address_tree, 0, 2,
! 		    decode_boolean_bitfield(addr, 0x0100, 2*8,
  			"EA1 = 1", "EA1 = 0 (Error)"), NULL);
! 	if (v120len == 5)
! 		dissect_v120_header(pd, 4, fd, v120_tree);
      }
      else
! 	v120_tree = NULL;
      dissect_xdlc_control(pd, 2, fd, v120_tree, hf_v120_control,
  	    ett_v120_control, is_response, v120len == 3 ? FALSE : TRUE);
  }
  
  void
+ dissect_v120_header(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
+ {
+ 	char info[80];
+ 	int header_len, nbits;
+ 	int header;
+ 	proto_tree *h_tree, *tc;
+ 
+ 	if (pd[offset] & 0x80) {
+ 		header_len = 1;
+ 		header = pd[offset];
+ 	} else {
+ 		header_len = 2;
+ 		header = pd[offset] | pd[offset + 1] << 8;
+ 	}
+ 	nbits = header_len * 8;
+ 	sprintf(info, "Header: B: %d F: %d", pd[offset] & 0x02 ? 1:0,
+ 			pd[offset] & 0x01 ? 1:0);
+ 	tc = proto_tree_add_item_format(tree, ett_v120_header,
+ 			offset, header_len,
+ 			"Header octet: %s (0x%02X)", info, pd[offset]);
+ 	h_tree = proto_item_add_subtree(tc, ett_v120_header);
+ 	proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x80, nbits,
+ 			"No extension octet", "Extension octet follows"), NULL);
+ 	proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x40, nbits,
+ 			"Break condition", "No break condition"), NULL);
+ 	sprintf(info, "Error control C1/C2: %d", (header & 0x0c) >> 2);
+ 	proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_numeric_bitfield(header, 0x0c, nbits, info));
+ 	proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x02, nbits,
+ 			"Segmentation bit B", "No segmentation bit B"), NULL);
+ 	proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x01, nbits,
+ 			"Segmentation bit F", "No segmentation bit F"), NULL);
+ 	if (header_len == 2) {
+ 		proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x8000, nbits,
+ 			"E", "E bit not set (Error)"), NULL);
+ 		proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x4000, nbits,
+ 			"DR", "No DR"), NULL);
+ 		proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x2000, nbits,
+ 			"SR", "No SR"), NULL);
+ 		proto_tree_add_text(h_tree, offset, header_len,
+ 		    decode_boolean_bitfield(header, 0x1000, nbits,
+ 			"RR", "No RR"), NULL);
+ 	}
+ }
+ void
  proto_register_v120(void)
  {
***************
*** 141,144 ****
--- 195,201 ----
  	  { "Control Field", "v120.control", FT_STRING, BASE_NONE, NULL, 0x0,
  	  	"" }},
+ 	{ &hf_v120_header,
+ 	  { "Header Field", "v120.header", FT_STRING, BASE_NONE, NULL, 0x0,
+ 	  	"" }},
      };
      static gint *ett[] = {
***************
*** 146,149 ****
--- 203,207 ----
          &ett_v120_address,
          &ett_v120_control,
+         &ett_v120_header,
      };