Discard the WTAP_ENCAP_LAPD encapsulation type in favor of a

WTAP_ENCAP_ISDN encapsulation type, which includes a pseudo-header
giving the direction (user-to-network or network-to-user) and the
channel number.

Add a new circuit type, using the ISDN channel number as the circuit ID.

Add an ISDN dissector to put the direction and channel number into the
protocol tree and to call the appropriate dissector for the payload
based on the channel (LAPD for the D channel; V.120, PPP, or data for B
channels, based on some heuristics).

svn path=/trunk/; revision=6521

1 files changed, 18 insertions, 67 deletions

diff --git a/wiretap/i4btrace.c b/wiretap/i4btrace.c
index 097608d87b..4e1cb3feb5 100644
--- a/wiretap/i4btrace.c
+++ b/wiretap/i4btrace.c
@@ -1,6 +1,6 @@
 /* i4btrace.c
  *
- * $Id: i4btrace.c,v 1.22 2002/07/29 06:09:58 guy Exp $
+ * $Id: i4btrace.c,v 1.23 2002/10/31 07:12:41 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1999 by Bert Driehuis <driehuis@playbeing.org>
@@ -38,7 +38,7 @@ static gboolean i4btrace_seek_read(wtap *wth, long seek_off,
 static int i4b_read_rec_header(FILE_T fh, i4b_trace_hdr_t *hdr, int *err);
 static void i4b_byte_swap_header(wtap *wth, i4b_trace_hdr_t *hdr);
 static gboolean i4b_read_rec_data(FILE_T fh, guchar *pd, int length, int *err);
-static void i4b_set_pseudo_header(wtap *wth, i4b_trace_hdr_t *hdr,
+static void i4b_set_pseudo_header(i4b_trace_hdr_t *hdr,
     union wtap_pseudo_header *pseudo_header);
 static void i4btrace_close(wtap *wth);
 
@@ -103,11 +103,9 @@ int i4btrace_open(wtap *wth, int *err)
 	wth->subtype_close = i4btrace_close;
 	wth->snapshot_length = 0;	/* not known */
 
-	wth->capture.i4btrace->bchannel_prot[0] = -1;
-	wth->capture.i4btrace->bchannel_prot[1] = -1;
 	wth->capture.i4btrace->byte_swapped = byte_swapped;
 
-	wth->file_encap = WTAP_ENCAP_PER_PACKET;
+	wth->file_encap = WTAP_ENCAP_ISDN;
 
 	return 1;
 }
@@ -121,7 +119,6 @@ static gboolean i4btrace_read(wtap *wth, int *err, long *data_offset)
 	i4b_trace_hdr_t hdr;
 	guint16 length;
 	void *bufp;
-	int channel;
 
 	/* Read record header. */
 	*data_offset = wth->data_offset;
@@ -165,58 +162,16 @@ static gboolean i4btrace_read(wtap *wth, int *err, long *data_offset)
 		break;
 
 	case TRC_CH_D:
-		/*
-		 * D channel, so it's LAPD.
-		 */
-		wth->phdr.pkt_encap = WTAP_ENCAP_LAPD;
-		break;
-
 	case TRC_CH_B1:
 	case TRC_CH_B2:
 		/*
-		 * B channel, so it could be any of a number of things.
+		 * D or B channel.
 		 */
-		channel = hdr.type - TRC_CH_B1;
-
-		if (wth->capture.i4btrace->bchannel_prot[channel] == -1) {
-			/*
-			 * We don't know yet whether the datastream is
-			 * V.120 or not; this heuristic tries to figure
-			 * that out.
-			 *
-			 * We cannot glean this from the Q.931 SETUP message,
-			 * because no commercial V.120 implementation I've
-			 * seen actually sets the V.120 protocol discriminator
-			 * (that, or I'm misreading the spec badly).
-			 *
-			 * TODO: reset the flag to -1 (unknown) after a close
-			 * on the B channel is detected.
-			 */
-			if (memcmp(bufp, V120SABME, 3) == 0)
-			    wth->capture.i4btrace->bchannel_prot[channel] = 1;
-			else
-			    wth->capture.i4btrace->bchannel_prot[channel] = 0;
-		}
-		if (wth->capture.i4btrace->bchannel_prot[channel] == 1) {
-			/*
-			 * V.120.
-			 */
-			wth->phdr.pkt_encap = WTAP_ENCAP_V120;
-		} else {
-			/*
-			 * Not V.120.
-			 *
-			 * XXX - what is it?  It's probably not
-			 * WTAP_ENCAP_NULL, as that means it has a
-			 * 4-byte AF_ type as the encapsulation header.
-			 * If it's PPP, we should use WTAP_ENCAP_PPP here.
-			 */
-			wth->phdr.pkt_encap = WTAP_ENCAP_NULL;
-		}
+		wth->phdr.pkt_encap = WTAP_ENCAP_ISDN;
 		break;
 	}
 
-	i4b_set_pseudo_header(wth, &hdr, &wth->pseudo_header);
+	i4b_set_pseudo_header(&hdr, &wth->pseudo_header);
 
 	return TRUE;
 }
@@ -243,7 +198,7 @@ i4btrace_seek_read(wtap *wth, long seek_off,
 	}
 	i4b_byte_swap_header(wth, &hdr);
 
-	i4b_set_pseudo_header(wth, &hdr, pseudo_header);
+	i4b_set_pseudo_header(&hdr, pseudo_header);
 
 	/*
 	 * Read the packet data.
@@ -307,35 +262,31 @@ i4b_read_rec_data(FILE_T fh, guchar *pd, int length, int *err)
 }
 
 static void
-i4b_set_pseudo_header(wtap *wth, i4b_trace_hdr_t *hdr,
+i4b_set_pseudo_header(i4b_trace_hdr_t *hdr,
     union wtap_pseudo_header *pseudo_header)
 {
-	int channel;
-
+	pseudo_header->isdn.uton = (hdr->dir == FROM_TE);
 	switch (hdr->type) {
 
 	case TRC_CH_D:
 		/*
 		 * D channel, so it's LAPD; set "p2p.sent".
 		 */
-		pseudo_header->p2p.sent = (hdr->dir == FROM_TE) ? TRUE : FALSE;
+		pseudo_header->isdn.channel = 0;
 		break;
 
 	case TRC_CH_B1:
-	case TRC_CH_B2:
 		/*
-		 * B channel, so it could be any of a number of things;
-		 * if it's V.120, set "x25.flags".
+		 * B channel 1.
 		 */
-		channel = hdr->type - TRC_CH_B1;
+		pseudo_header->isdn.channel = 1;
+		break;
 
-		if (wth->capture.i4btrace->bchannel_prot[channel] == 1) {
-			/*
-			 * V.120.
-			 */
-			pseudo_header->x25.flags =
-			    (hdr->dir == FROM_TE) ? 0x00 : FROM_DCE;
-		}
+	case TRC_CH_B2:
+		/*
+		 * B channel 2.
+		 */
+		pseudo_header->isdn.channel = 2;
 		break;
 	}
 }