Replace the old "erfatm" preference for the ERF dissector with an

"aal5_type" dissector, which offers only "guess the traffic type" and
"LLC multiplexed" as options, defaulting to "guess the type".

Add a separate preference to control whether to treat single ATM cells
as raw data or as the first cell of an AAL5 PDU (and dissecting them as
short AAL5 PDUs).

Don't reach inside the tvbuff to get the data and the length; use
tvb_length() and tvb_get_ptr().

Pass the data *after* the AAL5 header to the "guess the traffic type"
routine.

svn path=/trunk/; revision=25736

1 files changed, 77 insertions, 47 deletions

diff --git a/epan/dissectors/packet-erf.c b/epan/dissectors/packet-erf.c
index 9fdf79b70f..a96a4e9969 100644
--- a/epan/dissectors/packet-erf.c
+++ b/epan/dissectors/packet-erf.c
@@ -158,13 +158,14 @@ typedef enum {
 static gint erf_hdlc_default = ERF_HDLC_MAX;
 static dissector_handle_t erf_hdlc_dissector[ERF_HDLC_MAX];
 
+static gboolean erf_rawcell_first = FALSE;
+
 typedef enum {
-  ERF_ATM_ATM = 1,
-  ERF_ATM_LLC = 2,
-  ERF_ATM_MAX = 3
-} erf_atm_type;
-static gint erf_atm_default = ERF_ATM_MAX;
-static dissector_handle_t erf_atm_dissector[ERF_ATM_MAX];
+  ERF_AAL5_GUESS = 0,
+  ERF_AAL5_LLC = 1,
+} erf_aal5_type_val;
+static gint erf_aal5_type = ERF_AAL5_GUESS;
+static dissector_handle_t erf_atm_untruncated_dissector;
 
 static gboolean erf_ethfcs = TRUE;
 static dissector_handle_t erf_ethwithfcs_dissector, erf_ethwithoutfcs_dissector;
@@ -270,9 +271,10 @@ static const value_string erf_type_vals[] = {
   { ERF_TYPE_INFINIBAND, "INFINIBAND"},
   {0, NULL}
 };
+
 /* Copy of atm_guess_traffic_type from atm.c in /wiretap */
 static void
-erf_atm_guess_lane_type(const guint8 *pd, guint32 len,
+erf_atm_guess_lane_type(const guint8 *pd, guint len,
     union wtap_pseudo_header *pseudo_header)
 {
 	if (len >= 2) {
@@ -294,8 +296,9 @@ erf_atm_guess_lane_type(const guint8 *pd, guint32 len,
 		}
 	}
 }
+
 static void
-erf_atm_guess_traffic_type(const guint8 *pd, guint32 len,
+erf_atm_guess_traffic_type(const guint8 *pd, guint len,
     union wtap_pseudo_header *pseudo_header)
 {
 	/*
@@ -585,6 +588,8 @@ dissect_erf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
   guint32 atm_hdr=0;
   proto_item *erf_item = NULL;
   proto_tree *erf_tree = NULL;
+  guint atm_pdu_caplen;
+  const guint8 *atm_pdu;
   tvbuff_t *new_tvb;
 
   erf_type=pinfo->pseudo_header->erf.phdr.type;
@@ -659,19 +664,36 @@ dissect_erf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     pinfo->pseudo_header->atm.vci = ((atm_hdr & 0x000ffff0) >>  4);
     pinfo->pseudo_header->atm.channel = (flags & 0x03);
 
-    /* Work around to have decoding working */
-    pinfo->pseudo_header->atm.aal = AAL_UNKNOWN;
-    pinfo->pseudo_header->atm.type = TRAF_UNKNOWN;
-    pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
-      
     new_tvb = tvb_new_subset(tvb, ATM_HDR_LENGTH, -1, -1);
-    /* Try to guess the type according to the first bytes */
-    erf_atm_guess_traffic_type(tvb->real_data, tvb->length, pinfo->pseudo_header);
-      
-    if (erf_atm_default < ERF_ATM_MAX)
-      call_dissector(erf_atm_dissector[erf_atm_default], new_tvb, pinfo, tree);
-    else
-      proto_tree_add_text(tree, new_tvb, 0, -1, "The ERF_ATM Layer 2 preference for ERF is set to \"Raw data\"");
+    /* Work around to have decoding working */
+    if (erf_rawcell_first) {
+      /* Treat this as a (short) ATM AAL5 PDU */
+      pinfo->pseudo_header->atm.aal = AAL_5;
+      switch (erf_aal5_type) {
+
+      case ERF_AAL5_GUESS:
+        pinfo->pseudo_header->atm.type = TRAF_UNKNOWN;
+        pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
+        /* Try to guess the type according to the first bytes */
+        atm_pdu_caplen = tvb_length(new_tvb);
+        atm_pdu = tvb_get_ptr(new_tvb, 0, atm_pdu_caplen);
+        erf_atm_guess_traffic_type(atm_pdu, atm_pdu_caplen, pinfo->pseudo_header);
+        break;
+
+      case ERF_AAL5_LLC:
+        pinfo->pseudo_header->atm.type = TRAF_LLCMX;
+        pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
+        break;
+      }
+
+      call_dissector(erf_atm_untruncated_dissector, new_tvb, pinfo, tree);
+    } else {
+      /* Treat this as a raw cell */
+      pinfo->pseudo_header->atm.flags |= ATM_RAW_CELL;
+      pinfo->pseudo_header->atm.aal = AAL_UNKNOWN;
+
+      call_dissector(data_handle, new_tvb, pinfo, tree);
+    }
     break;
 
   case ERF_TYPE_MC_AAL5:
@@ -684,19 +706,28 @@ dissect_erf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     pinfo->pseudo_header->atm.vpi = ((atm_hdr & 0x0ff00000) >> 20);
     pinfo->pseudo_header->atm.vci = ((atm_hdr & 0x000ffff0) >>  4);
     pinfo->pseudo_header->atm.channel = (flags & 0x03);
+
+    new_tvb = tvb_new_subset(tvb, ATM_HDR_LENGTH, -1, -1);
     /* Work around to have decoding working */
     pinfo->pseudo_header->atm.aal = AAL_5;
-    pinfo->pseudo_header->atm.type = TRAF_UNKNOWN;
-    pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
+    switch (erf_aal5_type) {
+
+    case ERF_AAL5_GUESS:
+      pinfo->pseudo_header->atm.type = TRAF_UNKNOWN;
+      pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
+      /* Try to guess the type according to the first bytes */
+      atm_pdu_caplen = tvb_length(new_tvb);
+      atm_pdu = tvb_get_ptr(new_tvb, 0, atm_pdu_caplen);
+      erf_atm_guess_traffic_type(atm_pdu, atm_pdu_caplen, pinfo->pseudo_header);
+      break;
 
-    new_tvb = tvb_new_subset(tvb, ATM_HDR_LENGTH, -1, -1);
-    /* Try to guess the type according to the first bytes */
-    erf_atm_guess_traffic_type(tvb->real_data, tvb->length, pinfo->pseudo_header);  
+    case ERF_AAL5_LLC:
+      pinfo->pseudo_header->atm.type = TRAF_LLCMX;
+      pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
+      break;
+    }
 
-    if (erf_atm_default < ERF_ATM_MAX)
-      call_dissector(erf_atm_dissector[erf_atm_default], new_tvb, pinfo, tree);
-    else
-      proto_tree_add_text(tree, new_tvb, 0, -1, "The ERF_ATM Layer 2 preference for ERF is set to \"Raw data\"");
+    call_dissector(erf_atm_untruncated_dissector, new_tvb, pinfo, tree);
     break;
 
   case ERF_TYPE_MC_AAL2:
@@ -715,13 +746,7 @@ dissect_erf(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
     pinfo->pseudo_header->atm.subtype = TRAF_ST_UNKNOWN;
 
     new_tvb = tvb_new_subset(tvb, ATM_HDR_LENGTH, -1, -1);
-    /* Try to guess the type according to the first bytes */
-    erf_atm_guess_traffic_type(tvb->real_data, tvb->length, pinfo->pseudo_header);  
-
-    if (erf_atm_default < ERF_ATM_MAX)
-      call_dissector(erf_atm_dissector[erf_atm_default], new_tvb, pinfo, tree);
-    else
-      proto_tree_add_text(tree, new_tvb, 0, -1, "The ERF_ATM Layer 2 preference for ERF is set to \"Raw data\"");
+    call_dissector(erf_atm_untruncated_dissector, new_tvb, pinfo, tree);
     break;
 
   case ERF_TYPE_ETH:
@@ -885,10 +910,9 @@ proto_register_erf(void)
     { NULL, NULL, 0 }
   };
 
-  static enum_val_t erf_atm_options[] = { 
-    { "atm",   "ATM",      ERF_ATM_ATM },
-    { "llc",   "LLC",      ERF_ATM_LLC },
-    { "raw",   "Raw data", ERF_ATM_MAX },
+  static enum_val_t erf_aal5_options[] = { 
+    { "guess", "Attempt to guess", ERF_AAL5_GUESS },
+    { "llc",   "LLC multiplexed",  ERF_AAL5_LLC },
     { NULL, NULL, 0 }
   };
 
@@ -906,9 +930,16 @@ proto_register_erf(void)
                                  "Protocol encapsulated in HDLC records",
                                  &erf_hdlc_default, erf_hdlc_options, FALSE);
 
-  prefs_register_enum_preference(erf_module, "erfatm", "ERF_ATM Layer 2",
-                                 "Protocol encapsulated in ATM records",
-                                 &erf_atm_default, erf_atm_options, FALSE);
+  prefs_register_bool_preference(erf_module, "rawcell_first",
+                                 "Raw ATM cells are first cell of AAL5 PDU",
+                                 "Whether raw ATM cells should be treated as "
+                                 "the first cell of an AAL5 PDU",
+                                 &erf_rawcell_first);
+
+  prefs_register_enum_preference(erf_module, "aal5_type",
+                                 "ATM AAL5 packet type",
+                                 "Protocol encapsulated in ATM AAL5 packets",
+                                 &erf_aal5_type, erf_aal5_options, FALSE);
 
   prefs_register_bool_preference(erf_module, "ethfcs",
                                  "Ethernet packets have FCS",
@@ -936,11 +967,10 @@ proto_reg_handoff_erf(void)
   erf_hdlc_dissector[ERF_HDLC_FRELAY] = find_dissector("fr");
   erf_hdlc_dissector[ERF_HDLC_MTP2] = find_dissector("mtp2");
 
-  /* Create ERF_ATM dissectors table */  
-  erf_atm_dissector[ERF_ATM_ATM] = find_dissector("atm_untruncated");
-  erf_atm_dissector[ERF_ATM_LLC] = find_dissector("llc");
+  /* Get ATM dissector */
+  erf_atm_untruncated_dissector = find_dissector("atm_untruncated");
 
-  /* Create Ethernet dissectors table */
+  /* Get Ethernet dissectors */
   erf_ethwithfcs_dissector = find_dissector("eth_withfcs");  
   erf_ethwithoutfcs_dissector = find_dissector("eth_withoutfcs");
 }