1 files changed, 134 insertions, 0 deletions
diff --git a/wiretap/atm.c b/wiretap/atm.c
new file mode 100644
index 0000000..47b471d
--- /dev/null
+++ b/wiretap/atm.c
@@ -0,0 +1,134 @@
+/* atm.c
+ *
+ * Wiretap Library
+ * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+#include "wtap-int.h"
+#include "atm.h"
+
+/*
+ * Routines to use with ATM capture file types that don't include information
+ * about the *type* of ATM traffic (or, at least, where we haven't found
+ * that information).
+ *
+ * We assume the traffic is AAL5, unless it's VPI 0/VCI 5, in which case
+ * we assume it's the signalling AAL.
+ */
+
+void
+atm_guess_traffic_type(wtap_rec *rec, const guint8 *pd)
+{
+	/*
+	 * Start out assuming nothing other than that it's AAL5.
+	 */
+	rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_5;
+	rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_UNKNOWN;
+	rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_UNKNOWN;
+
+	if (rec->rec_header.packet_header.pseudo_header.atm.vpi == 0) {
+		/*
+		 * Traffic on some PVCs with a VPI of 0 and certain
+		 * VCIs is of particular types.
+		 */
+		switch (rec->rec_header.packet_header.pseudo_header.atm.vci) {
+
+		case 5:
+			/*
+			 * Signalling AAL.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
+			return;
+
+		case 16:
+			/*
+			 * ILMI.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_ILMI;
+			return;
+		}
+	}
+
+	/*
+	 * OK, we can't tell what it is based on the VPI/VCI; try
+	 * guessing based on the contents, if we have enough data
+	 * to guess.
+	 */
+
+	if (rec->rec_header.packet_header.caplen >= 3) {
+		if (pd[0] == 0xaa && pd[1] == 0xaa && pd[2] == 0x03) {
+			/*
+			 * Looks like a SNAP header; assume it's LLC
+			 * multiplexed RFC 1483 traffic.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_LLCMX;
+		} else if ((rec->rec_header.packet_header.pseudo_header.atm.aal5t_len && rec->rec_header.packet_header.pseudo_header.atm.aal5t_len < 16) ||
+		    rec->rec_header.packet_header.caplen < 16) {
+			/*
+			 * As this cannot be a LANE Ethernet frame (less
+			 * than 2 bytes of LANE header + 14 bytes of
+			 * Ethernet header) we can try it as a SSCOP frame.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
+		} else if (pd[0] == 0x83 || pd[0] == 0x81) {
+			/*
+			 * MTP3b headers often encapsulate
+			 * a SCCP or MTN in the 3G network.
+			 * This should cause 0x83 or 0x81
+			 * in the first byte.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
+		} else {
+			/*
+			 * Assume it's LANE.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.type = TRAF_LANE;
+			atm_guess_lane_type(rec, pd);
+		}
+	} else {
+	       /*
+		* Not only VCI 5 is used for signaling. It might be
+		* one of these VCIs.
+		*/
+	       rec->rec_header.packet_header.pseudo_header.atm.aal = AAL_SIGNALLING;
+	}
+}
+
+void
+atm_guess_lane_type(wtap_rec *rec, const guint8 *pd)
+{
+	if (rec->rec_header.packet_header.caplen >= 2) {
+		if (pd[0] == 0xff && pd[1] == 0x00) {
+			/*
+			 * Looks like LE Control traffic.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_LANE_LE_CTRL;
+		} else {
+			/*
+			 * XXX - Ethernet, or Token Ring?
+			 * Assume Ethernet for now; if we see earlier
+			 * LANE traffic, we may be able to figure out
+			 * the traffic type from that, but there may
+			 * still be situations where the user has to
+			 * tell us.
+			 */
+			rec->rec_header.packet_header.pseudo_header.atm.subtype = TRAF_ST_LANE_802_3;
+		}
+	}
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 8
+ * tab-width: 8
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vi: set shiftwidth=8 tabstop=8 noexpandtab:
+ * :indentSize=8:tabSize=8:noTabs=false:
+ */