Have a pseudo-header for Ethernet packets, giving the size of the FCS -

0 means "there is no FCS in the packet data", 4 means "there is an FCS
in the packet data", -1 means "I don't know whether there's an FCS in
the packet data, guess based on the packet size".

Assume that Ethernet encapsulated inside other protocols has no FCS, by
having the "eth" dissector assume that (and not check for an Ethernet
pseudo-header).

Have "ethertype()" take an argument giving the FCS size; pass 0 when
appropriate.

Fix up Wiretap routines to set the pseudo-header.  This means we no
longer use the "generic" seek-and-read routine, so get rid of it.

svn path=/trunk/; revision=8574

1 files changed, 64 insertions, 55 deletions

diff --git a/wiretap/iptrace.c b/wiretap/iptrace.c
index 8f5d2a9775..ddf2f1e114 100644
--- a/wiretap/iptrace.c
+++ b/wiretap/iptrace.c
@@ -1,6 +1,6 @@
 /* iptrace.c
  *
- * $Id: iptrace.c,v 1.47 2003/01/10 04:04:41 guy Exp $
+ * $Id: iptrace.c,v 1.48 2003/10/01 07:11:47 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
@@ -46,7 +46,7 @@ static int iptrace_read_rec_header(FILE_T fh, guint8 *header, int header_len,
     int *err);
 static gboolean iptrace_read_rec_data(FILE_T fh, guint8 *data_ptr,
     int packet_size, int *err);
-static void get_atm_pseudo_header(const guint8 *pd, guint32 len,
+static void fill_in_pseudo_header(int encap, const guint8 *pd, guint32 len,
     union wtap_pseudo_header *pseudo_header, guint8 *header);
 static int wtap_encap_ift(unsigned int  ift);
 
@@ -186,10 +186,9 @@ static gboolean iptrace_read_1_0(wtap *wth, int *err, long *data_offset)
 		return FALSE;
 	}
 
-	if (wth->phdr.pkt_encap == WTAP_ENCAP_ATM_PDUS) {
-		get_atm_pseudo_header(data_ptr, wth->phdr.caplen,
-		    &wth->pseudo_header, header);
-	}
+	/* Fill in the pseudo-header. */
+	fill_in_pseudo_header(wth->phdr.pkt_encap, data_ptr, wth->phdr.caplen,
+	    &wth->pseudo_header, header);
 
 	/* If the per-file encapsulation isn't known, set it to this
 	   packet's encapsulation.
@@ -252,9 +251,9 @@ static gboolean iptrace_seek_read_1_0(wtap *wth, long seek_off,
 	if (!iptrace_read_rec_data(wth->random_fh, pd, packet_size, err))
 		return FALSE;
 
-	/* Get the ATM pseudo-header, if this is ATM traffic. */
-	if (pkt_encap == WTAP_ENCAP_ATM_PDUS)
-		get_atm_pseudo_header(pd, packet_size, pseudo_header, header);
+	/* Fill in the pseudo_header. */
+	fill_in_pseudo_header(pkt_encap, pd, packet_size, pseudo_header,
+	    header);
 
 	return TRUE;
 }
@@ -369,10 +368,9 @@ static gboolean iptrace_read_2_0(wtap *wth, int *err, long *data_offset)
 		return FALSE;
 	}
 
-	if (wth->phdr.pkt_encap == WTAP_ENCAP_ATM_PDUS) {
-		get_atm_pseudo_header(data_ptr, wth->phdr.caplen,
-		    &wth->pseudo_header, header);
-	}
+	/* Fill in the pseudo-header. */
+	fill_in_pseudo_header(wth->phdr.pkt_encap, data_ptr, wth->phdr.caplen,
+	    &wth->pseudo_header, header);
 
 	/* If the per-file encapsulation isn't known, set it to this
 	   packet's encapsulation.
@@ -435,9 +433,9 @@ static gboolean iptrace_seek_read_2_0(wtap *wth, long seek_off,
 	if (!iptrace_read_rec_data(wth->random_fh, pd, packet_size, err))
 		return FALSE;
 
-	/* Get the ATM pseudo-header, if this is ATM traffic. */
-	if (pkt_encap == WTAP_ENCAP_ATM_PDUS)
-		get_atm_pseudo_header(pd, packet_size, pseudo_header, header);
+	/* Fill in the pseudo-header. */
+	fill_in_pseudo_header(pkt_encap, pd, packet_size, pseudo_header,
+	    header);
 
 	return TRUE;
 }
@@ -480,15 +478,16 @@ iptrace_read_rec_data(FILE_T fh, guint8 *data_ptr, int packet_size, int *err)
 }
 
 /*
- * Fill in the pseudo-header information we can; alas, "iptrace" doesn't
- * tell us what type of traffic is in the packet - it was presumably
- * run on a machine that was one of the endpoints of the connection, so
- * in theory it could presumably have told us, but, for whatever reason,
- * it failed to do so - perhaps the low-level mechanism that feeds the
- * presumably-AAL5 frames to us doesn't have access to that information
- * (e.g., because it's in the ATM driver, and the ATM driver merely knows
- * that stuff on VPI/VCI X.Y should be handed up to some particular
- * client, it doesn't know what that client is).
+ * Fill in the pseudo-header information we can.
+ *
+ * For ATM traffic, "iptrace", alas, doesn't tell us what type of traffic
+ * is in the packet - it was presumably run on a machine that was one of
+ * the endpoints of the connection, so in theory it could presumably have
+ * told us, but, for whatever reason, it failed to do so - perhaps the
+ * low-level mechanism that feeds the presumably-AAL5 frames to us doesn't
+ * have access to that information (e.g., because it's in the ATM driver,
+ * and the ATM driver merely knows that stuff on VPI/VCI X.Y should be
+ * handed up to some particular client, it doesn't know what that client is).
  *
  * We let our caller try to figure out what kind of traffic it is, either
  * by guessing based on the VPI/VCI, guessing based on the header of the
@@ -496,7 +495,7 @@ iptrace_read_rec_data(FILE_T fh, guint8 *data_ptr, int packet_size, int *err)
  * in some fashion what sort of traffic it is, or being told by the user.
  */
 static void
-get_atm_pseudo_header(const guint8 *pd, guint32 len,
+fill_in_pseudo_header(int encap, const guint8 *pd, guint32 len,
     union wtap_pseudo_header *pseudo_header, guint8 *header)
 {
 	char	if_text[9];
@@ -504,38 +503,48 @@ get_atm_pseudo_header(const guint8 *pd, guint32 len,
 	int	Vpi = 0;
 	int	Vci = 0;
 
-	/* Rip apart the "x.y" text into Vpi/Vci numbers */
-	memcpy(if_text, &header[20], 8);
-	if_text[8] = '\0';
-	decimal = strchr(if_text, '.');
-	if (decimal) {
-		*decimal = '\0';
-		Vpi = strtoul(if_text, NULL, 10);
-		decimal++;
-		Vci = strtoul(decimal, NULL, 10);
-	}
+	switch (encap) {
+
+	case WTAP_ENCAP_ATM_PDUS:
+		/* Rip apart the "x.y" text into Vpi/Vci numbers */
+		memcpy(if_text, &header[20], 8);
+		if_text[8] = '\0';
+		decimal = strchr(if_text, '.');
+		if (decimal) {
+			*decimal = '\0';
+			Vpi = strtoul(if_text, NULL, 10);
+			decimal++;
+			Vci = strtoul(decimal, NULL, 10);
+		}
 
-	/*
-	 * OK, which value means "DTE->DCE" and which value means
-	 * "DCE->DTE"?
-	 */
-	pseudo_header->atm.channel = header[29];
+		/*
+		 * OK, which value means "DTE->DCE" and which value means
+		 * "DCE->DTE"?
+		 */
+		pseudo_header->atm.channel = header[29];
 
-	pseudo_header->atm.vpi = Vpi;
-	pseudo_header->atm.vci = Vci;
+		pseudo_header->atm.vpi = Vpi;
+		pseudo_header->atm.vci = Vci;
 
-	/*
-	 * Attempt to guess from the packet data, the VPI, and the VCI
-	 * information about the type of traffic.
-	 */
-	atm_guess_traffic_type(pd, len, pseudo_header);
-
-	/* We don't have this information */
-	pseudo_header->atm.flags = 0;
-	pseudo_header->atm.cells = 0;
-	pseudo_header->atm.aal5t_u2u = 0;
-	pseudo_header->atm.aal5t_len = 0;
-	pseudo_header->atm.aal5t_chksum = 0;
+		/*
+		 * Attempt to guess from the packet data, the VPI,
+		 * and the VCI information about the type of traffic.
+		 */
+		atm_guess_traffic_type(pd, len, pseudo_header);
+
+		/* We don't have this information */
+		pseudo_header->atm.flags = 0;
+		pseudo_header->atm.cells = 0;
+		pseudo_header->atm.aal5t_u2u = 0;
+		pseudo_header->atm.aal5t_len = 0;
+		pseudo_header->atm.aal5t_chksum = 0;
+		break;
+
+	case WTAP_ENCAP_ETHERNET:
+		/* We assume there's no FCS in this frame. */
+		pseudo_header->eth.fcs_len = 0;
+		break;
+	}
 }
 
 /* Given an RFC1573 (SNMP ifType) interface type,