ieee80211: Make a few dissector tables for vendor specific functionality

This allows vendors to more easily expand functionality.

Change-Id: Iaa6a0626f3ab3c80a3ea90ca09c90284705d0221
Reviewed-on: https://code.wireshark.org/review/23066
Reviewed-by: Richard Sharpe <realrichardsharpe@gmail.com>

1 files changed, 37 insertions, 29 deletions

diff --git a/epan/dissectors/packet-wifi-p2p.c b/epan/dissectors/packet-wifi-p2p.c
index ee6cdfb0e6..0a5ab5884a 100644
--- a/epan/dissectors/packet-wifi-p2p.c
+++ b/epan/dissectors/packet-wifi-p2p.c
@@ -421,7 +421,6 @@ static int hf_p2p_anqp_query_data = -1;
 static int hf_p2p_anqp_status_code = -1;
 static int hf_p2p_anqp_response_data = -1;
 
-static int hf_p2p_wfa_subtype = -1;
 static int hf_p2p_action_subtype = -1;
 static int hf_p2p_action_dialog_token = -1;
 static int hf_p2p_public_action_subtype = -1;
@@ -432,6 +431,8 @@ static expert_field ei_wifi_p2p_attr_len = EI_INIT;
 static expert_field ei_wifi_p2p_anqp_length = EI_INIT;
 static expert_field ei_wifi_p2p_anqp_unexpected_padding = EI_INIT;
 
+dissector_handle_t wifi_display_ie_handle;
+
 static void dissect_wifi_p2p_capability(proto_item *tlv_root,
                                         proto_item *tlv_item,
                                         tvbuff_t *tvb, int offset)
@@ -1060,12 +1061,13 @@ static void dissect_persistent_group(proto_item *tlv_root,
 
 }
 
-
-void dissect_wifi_p2p_ie(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
-                         int offset, gint size)
+static int
+dissect_wifi_p2p_ie(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data _U_)
 {
   guint16 slen = 0;
   guint8 stype = 0;
+  int offset = 0;
+  int size = tvb_reported_length(tvb);
   proto_item *tlv_root, *tlv_item;
 
   while (size > 0) {
@@ -1173,11 +1175,14 @@ void dissect_wifi_p2p_ie(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
     offset += 3 + slen;
     size -= 3 + slen;
   }
+
+  return tvb_captured_length(tvb);
 }
 
-int dissect_wifi_p2p_public_action(packet_info *pinfo, proto_tree *tree,
-                                   tvbuff_t *tvb, int offset)
+static int
+dissect_wifi_p2p_public_action(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
 {
+  int offset = 0;
   guint8 subtype;
   proto_tree_add_item(tree, hf_p2p_public_action_subtype, tvb, offset, 1,
                       ENC_BIG_ENDIAN);
@@ -1197,33 +1202,31 @@ static int
 dissect_wifi_p2p_action(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data _U_)
 {
   int offset = 0;
-  guint32 subtype;
 
-  proto_tree_add_item_ret_uint(tree, hf_p2p_wfa_subtype, tvb, offset, 1, ENC_NA, &subtype);
+  proto_tree_add_item(tree, hf_p2p_action_subtype, tvb, offset, 1, ENC_BIG_ENDIAN);
+  offset++;
+  proto_tree_add_item(tree, hf_p2p_action_dialog_token, tvb, offset, 1, ENC_BIG_ENDIAN);
   offset++;
-
-  if (subtype == 9 /* WFA_SUBTYPE_P2P */ )
-  {
-    proto_tree_add_item(tree, hf_p2p_action_subtype, tvb, offset, 1, ENC_BIG_ENDIAN);
-    offset++;
-    proto_tree_add_item(tree, hf_p2p_action_dialog_token, tvb, offset, 1, ENC_BIG_ENDIAN);
-    offset++;
-  }
 
   /* Followed by variable length IEs dissected by packet-ieee80211.c */
   return offset;
 }
 
-void dissect_wifi_p2p_anqp(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
-                           int offset, gboolean request)
+static int
+dissect_wifi_p2p_anqp(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void *data)
 {
+  int offset = 0;
   proto_item *item;
+  anqp_info_dissector_data_t* anqp_data = (anqp_info_dissector_data_t*)data;
+  tvbuff_t *next_tvb;
+
+  DISSECTOR_ASSERT(anqp_data);
 
   item = proto_tree_add_item(tree, hf_p2p_anqp_service_update_indicator, tvb,
                              offset, 2, ENC_LITTLE_ENDIAN);
   offset += 2;
 
-  while (tvb_reported_length_remaining(tvb, offset) >= (request ? 4 : 5)) {
+  while (tvb_reported_length_remaining(tvb, offset) >= (anqp_data->request ? 4 : 5)) {
     guint16 len;
     proto_tree *tlv;
     guint8 type, id, sd_proto;
@@ -1231,11 +1234,11 @@ void dissect_wifi_p2p_anqp(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
     len = tvb_get_letohs(tvb, offset);
     if (len < 2) {
       expert_add_info_format(pinfo, item, &ei_wifi_p2p_anqp_length, "Too short Service TLV field");
-      return;
+      return offset;
     }
     if (len > tvb_reported_length_remaining(tvb, offset + 2)) {
       expert_add_info_format(pinfo, item, &ei_wifi_p2p_anqp_length, "Too short frame for Service TLV field");
-      return;
+      return offset;
     }
 
     type = tvb_get_guint8(tvb, offset + 2);
@@ -1252,7 +1255,7 @@ void dissect_wifi_p2p_anqp(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
                         offset, 1, ENC_BIG_ENDIAN);
     proto_tree_add_item(tlv, hf_p2p_anqp_service_transaction_id, tvb,
                         offset + 1, 1, ENC_BIG_ENDIAN);
-    if (request) {
+    if (anqp_data->request) {
       proto_tree_add_item(tlv, hf_p2p_anqp_query_data, tvb,
                           offset + 2, len - 2, ENC_NA);
     } else {
@@ -1260,8 +1263,10 @@ void dissect_wifi_p2p_anqp(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
                           offset + 2, 1, ENC_BIG_ENDIAN);
       proto_tree_add_item(tlv, hf_p2p_anqp_response_data, tvb,
                           offset + 3, len - 3, ENC_NA);
-      if (sd_proto == 4)
-        dissect_wifi_display_ie(pinfo, tlv, tvb, offset + 3, len - 3);
+      if (sd_proto == 4) {
+        next_tvb = tvb_new_subset_length(tvb, offset + 3, len - 3);
+        call_dissector(wifi_display_ie_handle, next_tvb, pinfo, tlv);
+      }
     }
     offset += len;
   }
@@ -1269,6 +1274,8 @@ void dissect_wifi_p2p_anqp(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb,
   if (tvb_reported_length_remaining(tvb, offset) > 0) {
     expert_add_info(pinfo, item, &ei_wifi_p2p_anqp_unexpected_padding);
   }
+
+  return tvb_captured_length(tvb);
 }
 
 void
@@ -1788,10 +1795,6 @@ proto_register_p2p(void)
       { "Response Data", "wifi_p2p.anqp.response_data",
         FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
 
-    {&hf_p2p_wfa_subtype,
-     {"WFA Subtype", "wifi_p2p.wfa_subtype",
-      FT_UINT8, BASE_DEC, NULL, 0,
-      NULL, HFILL }},
     { &hf_p2p_action_subtype,
       { "P2P Action Subtype", "wifi_p2p.action.subtype",
         FT_UINT8, BASE_DEC, VALS(p2p_action_subtypes), 0x0, NULL, HFILL }},
@@ -1834,7 +1837,12 @@ proto_register_p2p(void)
 void
 proto_reg_handoff_p2p(void)
 {
-  dissector_add_uint("wlan.action.vendor_specific", OUI_WFA, create_dissector_handle(dissect_wifi_p2p_action, proto_p2p));
+  dissector_add_uint("wlan.action.wifi_alliance.subtype", WFA_SUBTYPE_P2P, create_dissector_handle(dissect_wifi_p2p_action, proto_p2p));
+  dissector_add_uint("wlan.anqp.wifi_alliance.subtype", WFA_SUBTYPE_P2P, create_dissector_handle(dissect_wifi_p2p_anqp, proto_p2p));
+  dissector_add_uint("wlan.ie.wifi_alliance.subtype", WFA_SUBTYPE_P2P, create_dissector_handle(dissect_wifi_p2p_ie, proto_p2p));
+  dissector_add_uint("wlan.pa.wifi_alliance.subtype", WFA_SUBTYPE_P2P, create_dissector_handle(dissect_wifi_p2p_public_action, proto_p2p));
+
+  wifi_display_ie_handle = find_dissector_add_dependency("wifi_display_ie", proto_p2p);
 }
 
 /*