UMTS FP: Track Paging Indications in PCH

The dissector now carries the 'Paging Indication Bitmap' between subsequent PCH frames.
The reason for this is any frame containing the bitmap 'wakes up' users to read the subsequence frame. This feature allows us to see which paging groups were called for each frame.
Also refactored some Paging Indication related fields in the umts convoersation object and tree items.

Change-Id: I5e55e916ec31b60bc93238b397e07a1260906736
Reviewed-on: https://code.wireshark.org/review/21686
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 91 insertions, 8 deletions

diff --git a/epan/dissectors/packet-umts_fp.c b/epan/dissectors/packet-umts_fp.c
index 168f251f96..1b17a4a19c 100644
--- a/epan/dissectors/packet-umts_fp.c
+++ b/epan/dissectors/packet-umts_fp.c
@@ -94,6 +94,7 @@ static int hf_fp_pch_tfi = -1;
 static int hf_fp_fach_tfi = -1;
 static int hf_fp_transmit_power_level = -1;
 static int hf_fp_paging_indication_bitmap = -1;
+static int hf_fp_relevant_paging_indication_bitmap = -1;
 static int hf_fp_pdsch_set_id = -1;
 static int hf_fp_rx_timing_deviation = -1;
 static int hf_fp_dch_e_rucch_flag = -1;
@@ -200,6 +201,7 @@ static int hf_fp_extended_bits = -1;
 static int hf_fp_spare_extension = -1;
 static int hf_fp_ul_setup_frame = -1;
 static int hf_fp_dl_setup_frame = -1;
+static int hf_fp_relevant_pi_frame = -1;
 
 /* Subtrees. */
 static int ett_fp = -1;
@@ -214,6 +216,7 @@ static int ett_fp_edch_macis_descriptors = -1;
 static int ett_fp_hsdsch_new_ie_flags = -1;
 static int ett_fp_rach_new_ie_flags = -1;
 static int ett_fp_hsdsch_pdu_block_header = -1;
+static int ett_fp_pch_relevant_pi = -1;
 
 static expert_field ei_fp_hsdsch_common_experimental_support = EI_INIT;
 static expert_field ei_fp_hsdsch_common_t3_not_implemented = EI_INIT;
@@ -253,6 +256,7 @@ static gboolean preferences_call_mac_dissectors = TRUE;
 static gboolean preferences_show_release_info = TRUE;
 static gboolean preferences_payload_checksum = TRUE;
 static gboolean preferences_header_checksum = TRUE;
+static gboolean preferences_track_paging_indications = TRUE;
 
 #define UMTS_FP_USE_UAT 1
 
@@ -2045,8 +2049,38 @@ dissect_pch_channel_info(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
                                      (p_fp_info->paging_indications+7) / 8,
                                      ENC_NA);
             proto_item_append_text(ti, " (%u bits)", p_fp_info->paging_indications);
+
+            if(preferences_track_paging_indications && !pinfo->fd->flags.visited){
+                paging_indications_info_t* current_pi_info;
+                current_pi_info = wmem_new0(wmem_file_scope(), paging_indications_info_t);
+                current_pi_info->frame_number = pinfo->num;
+                current_pi_info->paging_indications_bitmap = (guint8*)tvb_memdup(wmem_file_scope(), tvb, offset, (p_fp_info->paging_indications+7) / 8);
+                p_fp_info->current_paging_indications = current_pi_info;
+            }
+
             offset += ((p_fp_info->paging_indications+7) / 8);
         }
+        if(preferences_track_paging_indications && p_fp_info->relevant_paging_indications) {
+            /*If tracking PI is enabled and PI info (from the last packet) is attached, show on tree*/
+            proto_tree *relevant_pi_tree;
+            proto_item *ti;
+            tvbuff_t *pi_tvb;
+            pi_tvb = tvb_new_child_real_data(tvb,
+                                             p_fp_info->relevant_paging_indications->paging_indications_bitmap,
+                                             (p_fp_info->paging_indications+7) / 8,
+                                             (p_fp_info->paging_indications+7) / 8);
+            add_new_data_source(pinfo, pi_tvb, "Relevant Paging Indication");
+            ti = proto_tree_add_item(tree, hf_fp_relevant_paging_indication_bitmap, pi_tvb,
+                                     0,
+                                     (p_fp_info->paging_indications+7) / 8,
+                                     ENC_NA);
+            proto_item_append_text(ti, " (%u bits)", p_fp_info->paging_indications);
+            PROTO_ITEM_SET_GENERATED(ti);
+            relevant_pi_tree = proto_item_add_subtree(ti, ett_fp_pch_relevant_pi);
+            ti = proto_tree_add_uint(relevant_pi_tree, hf_fp_relevant_pi_frame,
+                                                       tvb, 0, 0, p_fp_info->relevant_paging_indications->frame_number);
+            PROTO_ITEM_SET_GENERATED(ti);
+        }
 
         /* TB data */
         offset = dissect_tb_data(tvb, pinfo, tree, offset, p_fp_info, &mac_fdd_pch_handle, data);
@@ -3942,6 +3976,7 @@ fill_pch_coversation_info_for_heur(umts_fp_conversation_info_t* umts_fp_conversa
     umts_fp_conversation_info->num_dch_in_flow = 1;
     umts_fp_conversation_info->fp_dch_channel_info[0].num_dl_chans = 1;
     umts_fp_conversation_info->fp_dch_channel_info[0].dl_chan_num_tbs[1] = 1;
+    umts_fp_conversation_info->channel_specific_info = (void*)wmem_new0(wmem_file_scope(), fp_pch_channel_info_t);
 }
 /* Attaches conversation info to both the downlink and uplink 'conversations' (streams) */
 /* (Required since only one of them is checked in every dissected FP packet) */
@@ -4325,6 +4360,7 @@ heur_dissect_fp_pch(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *d
 {
     conversation_t   *p_conv;
     umts_fp_conversation_info_t* umts_fp_conversation_info = NULL;
+    fp_pch_channel_info_t* fp_pch_channel_info = NULL;
     struct fp_info *p_fp_info;
     int length;
     guint8 frame_type;
@@ -4352,8 +4388,10 @@ heur_dissect_fp_pch(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *d
         /* Checking if the conversation was already framed */
         umts_fp_conversation_info = (umts_fp_conversation_info_t *)conversation_get_proto_data(p_conv, proto_fp);
         if (umts_fp_conversation_info) {
-            if (umts_fp_conversation_info->channel == CHANNEL_PCH) {
-                pi_length_found = umts_fp_conversation_info->paging_indications != 0;
+            fp_pch_channel_info = (fp_pch_channel_info_t*)umts_fp_conversation_info->channel_specific_info;
+            /* Making sure this conversation type is "PCH" and the PCH channel info is present */
+            if (umts_fp_conversation_info->channel == CHANNEL_PCH && fp_pch_channel_info != NULL) {
+                pi_length_found = fp_pch_channel_info->paging_indications != 0;
                 tb_size_found = umts_fp_conversation_info->fp_dch_channel_info[0].dl_chan_tf_size[1] != 0;
                 if (pi_length_found && tb_size_found) {
                     /* Stream already framed - contains both PI length and TB size */
@@ -4433,17 +4471,19 @@ heur_dissect_fp_pch(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *d
             if (!umts_fp_conversation_info) {
                 umts_fp_conversation_info = wmem_new0(wmem_file_scope(), umts_fp_conversation_info_t);
                 fill_pch_coversation_info_for_heur(umts_fp_conversation_info, pinfo);
+                fp_pch_channel_info = (fp_pch_channel_info_t*)umts_fp_conversation_info->channel_specific_info;
             }
-            umts_fp_conversation_info->paging_indications = pi_bit_length;
+            fp_pch_channel_info->paging_indications = pi_bit_length;
             set_both_sides_umts_fp_conv_data(pinfo, umts_fp_conversation_info);
             pi_length_found = TRUE;
         }
         else if (tfi == 0x01 && !tb_size_found && pi_length_found) {
             /* TB present and PI bitmap length is known. Can calculate TB length.*/
-            pi_byte_length = (umts_fp_conversation_info->paging_indications + 7) / 8;
+            pi_byte_length = (fp_pch_channel_info->paging_indications + 7) / 8;
             if (!umts_fp_conversation_info) {
                 umts_fp_conversation_info = wmem_new0(wmem_file_scope(), umts_fp_conversation_info_t);
                 fill_pch_coversation_info_for_heur(umts_fp_conversation_info, pinfo);
+                fp_pch_channel_info = (fp_pch_channel_info_t*)umts_fp_conversation_info->channel_specific_info;
             }
             tb_byte_length = (length - (pi_byte_length + 6)) * 8; /* Removing header length (4), footer length (2) and PI bitmap length*/
             /* Possible TB lengths for PCH is 10 or 30 bytes ( See 3GPP TR 25.944 / 4.1.1.2 ) */
@@ -4878,6 +4918,7 @@ fp_set_per_packet_inf_from_conv(conversation_t *p_conv,
     guint8 fake_lchid=0;
     gint *cur_val=NULL;
     guint32 user_identity;
+    fp_pch_channel_info_t *fp_pch_channel_info;
 
     fpi = wmem_new0(wmem_file_scope(), fp_info);
     p_add_proto_data(wmem_file_scope(), pinfo, proto_fp, 0, fpi);
@@ -5002,14 +5043,18 @@ fp_set_per_packet_inf_from_conv(conversation_t *p_conv,
             return fpi;
 
         case CHANNEL_PCH:
-            fpi->paging_indications = p_conv_data->paging_indications;
+            fp_pch_channel_info = (fp_pch_channel_info_t*)p_conv_data->channel_specific_info;
+            fpi->paging_indications = fp_pch_channel_info->paging_indications;
             fpi->num_chans = p_conv_data->num_dch_in_flow;
-            /* Set offset to point to first TFI
-             */
+
             if (is_control_frame) {
                 /* control frame, we're done */
                 return fpi;
             }
+            /* Inesrting Paging Indication Info extracted from the previous packet */
+            fpi->relevant_paging_indications = fp_pch_channel_info->last_paging_indication_info;
+            fp_pch_channel_info->last_paging_indication_info = NULL;
+
             /* Set offset to TFI */
             offset = 3;
             break;
@@ -5199,6 +5244,24 @@ fp_set_per_packet_inf_from_conv(conversation_t *p_conv,
     return fpi;
 }
 
+/* Updates the conversation info of a PCH stream based on information parsed in the current frame*/
+static void
+update_pch_coversation_info(umts_fp_conversation_info_t *p_conv_data, packet_info *pinfo, struct fp_info *p_fp_info)
+{
+    fp_pch_channel_info_t* fp_pch_channel_info;
+    /* The channel type MUST be set to PCH */
+    DISSECTOR_ASSERT(p_conv_data->channel == CHANNEL_PCH);
+
+    fp_pch_channel_info = (fp_pch_channel_info_t*)p_conv_data->channel_specific_info;
+    if(p_fp_info->current_paging_indications && !pinfo->fd->flags.visited)
+    {
+        /* Saving the PI info for the next packet to find */
+        fp_pch_channel_info->last_paging_indication_info = p_fp_info->current_paging_indications;
+        /* Resetting this field so we don't add it again to the conversation next time the packet is parsed */
+        p_fp_info->current_paging_indications = NULL;
+    }
+}
+
 /*****************************/
 /* Main dissection function. */
 static int
@@ -5404,6 +5467,7 @@ dissect_fp_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *dat
         case CHANNEL_PCH:
             dissect_pch_channel_info(tvb, pinfo, fp_tree, offset, p_fp_info,
                                      data);
+            update_pch_coversation_info(p_conv_data, pinfo, p_fp_info);
             break;
         case CHANNEL_CPCH:
             dissect_cpch_channel_info(tvb, pinfo, fp_tree, offset, p_fp_info);
@@ -5856,10 +5920,16 @@ void proto_register_fp(void)
             },
             { &hf_fp_paging_indication_bitmap,
               { "Paging Indications bitmap",
-                "fp.pch.pi-bitmap", FT_NONE, BASE_NONE, NULL, 0x0,
+                "fp.pch.pi-bitmap", FT_BYTES , BASE_NONE, NULL, 0x0,
                 "Paging Indication bitmap", HFILL
               }
             },
+            { &hf_fp_relevant_paging_indication_bitmap,
+              { "Relevant Paging Indications bitmap",
+                "fp.pch.relevant-pi-bitmap", FT_BYTES , BASE_NONE, NULL, 0x0,
+                "The Paging Indication bitmap used to inform users about the current frame", HFILL
+              }
+            },
             { &hf_fp_rx_timing_deviation,
               { "Rx Timing Deviation",
                 "fp.common.control.rx-timing-deviation", FT_UINT8, BASE_DEC, 0, 0x0,
@@ -6520,6 +6590,13 @@ void proto_register_fp(void)
                 NULL, HFILL
               }
             },
+            { &hf_fp_relevant_pi_frame,
+              { "Paging Indications frame number",
+                "fp.pch.relevant-pi-frame", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
+                "The frame where this Paging Indication bitmap was found",
+                HFILL
+              }
+            },
             { &hf_fp_hsdsch_physical_layer_category,
               { "HS-DSCH physical layer category",
                 "fp.hsdsch.physical_layer_category", FT_UINT8, BASE_DEC, NULL, 0x0,
@@ -6542,6 +6619,7 @@ void proto_register_fp(void)
         &ett_fp_hsdsch_new_ie_flags,
         &ett_fp_rach_new_ie_flags,
         &ett_fp_hsdsch_pdu_block_header,
+        &ett_fp_pch_relevant_pi,
         &ett_fp_release
     };
 
@@ -6645,6 +6723,11 @@ void proto_register_fp(void)
                                     "Validate FP header checksums",
                                     &preferences_header_checksum);
      /* Determines whether or not to validate FP header checksums */
+     prefs_register_bool_preference(fp_module, "track_paging_indications",
+                                    "Track Paging Indications in PCH channels",
+                                    "For each PCH data frame, Try to show the paging indications bitmap found in the previous frame",
+                                    &preferences_track_paging_indications);
+     /* Determines whether or not to validate FP header checksums */
     prefs_register_obsolete_preference(fp_module, "udp_heur");
 #ifdef UMTS_FP_USE_UAT