Call the "802.11 radio information" dissector for radio headers.

Have dissectors of various forms of radio information headers in the
packets fill in a struct ieee_802_11_phdr with radio information as
appropriate, and call the "802.11 radio information" dissector rather
than the raw 802.11 dissector.

This means that the radio information can be found in a
protocol-independent and encapsulation-independent form when you're
looking at the packet; that information can be presented in a form
somewhat easier to read than the raw metadata header format.

It also enables having a single "radio information" tap that allows
statistics to handle all different sorts of radio information
encapsulation.

In addition, it lets us clean up some of the arguments passed to the
common 802.11 dissector routine, by having it pull that information from
the struct ieee_802_11_phdr.

Ensure that the right structure gets passed to that routine, and that
all the appropriate parts of that structure are filled in.

Rename the 802.11 radio protocol to "wlan_radio", rather than just
"radio", as it's 802.11-specific.  Give all its fields "wlan_radio."
names rather than "wlan." names.

Change-Id: I78d79afece0ce0cf5fc17293c1e29596413b31c8
Reviewed-on: https://code.wireshark.org/review/8992
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 76 insertions, 21 deletions

diff --git a/epan/dissectors/packet-ieee80211-radiotap.c b/epan/dissectors/packet-ieee80211-radiotap.c
index be696547a2..78bb206a17 100644
--- a/epan/dissectors/packet-ieee80211-radiotap.c
+++ b/epan/dissectors/packet-ieee80211-radiotap.c
@@ -215,8 +215,7 @@ static expert_field ei_radiotap_data_past_header = EI_INIT;
 static expert_field ei_radiotap_present_reserved = EI_INIT;
 static expert_field ei_radiotap_present = EI_INIT;
 
-static dissector_handle_t ieee80211_handle;
-static dissector_handle_t ieee80211_datapad_handle;
+static dissector_handle_t ieee80211_radio_handle;
 
 static int radiotap_tap = -1;
 
@@ -608,6 +607,7 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 	/* We don't have any 802.11 metadata yet. */
 	phdr.fcs_len = -1;
 	phdr.decrypted = FALSE;
+	phdr.datapad = FALSE;
 	phdr.presence_flags = 0;
 
 	col_set_str(pinfo->cinfo, COL_PROTOCOL, "WLAN");
@@ -826,6 +826,8 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 
 		case IEEE80211_RADIOTAP_TSFT:
 			radiotap_info->tsft = tvb_get_letoh64(tvb, offset);
+			phdr.tsf_timestamp = radiotap_info->tsft;
+			phdr.presence_flags |= PHDR_802_11_HAS_TSF_TIMESTAMP;
 			if (tree) {
 				proto_tree_add_uint64(radiotap_tree,
 						      hf_radiotap_mactime, tvb,
@@ -836,10 +838,22 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 
 		case IEEE80211_RADIOTAP_FLAGS: {
 			rflags = tvb_get_guint8(tvb, offset);
+			if (rflags & IEEE80211_RADIOTAP_F_DATAPAD)
+				phdr.datapad = TRUE;
 			if (rflags & IEEE80211_RADIOTAP_F_FCS)
 				phdr.fcs_len = 4;
 			else
 				phdr.fcs_len = 0;
+			/*
+			 * This is "Currently unspecified but used",
+			 * according to the radiotap.org page for
+			 * the Flags field.
+			 */
+			phdr.presence_flags |= PHDR_802_11_HAS_SHORT_GI;
+			if (rflags & 0x80)
+				phdr.short_gi = 1;
+			else
+				phdr.short_gi = 0;
 
 			if (tree) {
 				proto_tree *flags_tree;
@@ -938,11 +952,22 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 								    (float)rate / 2);
 				}
 				radiotap_info->rate = rate;
+				phdr.presence_flags |= PHDR_802_11_HAS_DATA_RATE;
+				phdr.data_rate = rate;
 			}
 			break;
 		}
 
 		case IEEE80211_RADIOTAP_CHANNEL: {
+			freq	 = tvb_get_letohs(tvb, offset);
+			if (freq != 0) {
+				/*
+				 * XXX - some captures have 0, which is
+				 * obviously bogus.
+				 */
+				phdr.presence_flags |= PHDR_802_11_HAS_FREQUENCY;
+				phdr.frequency = freq;
+			}
 			if (tree) {
 				guint16     flags;
 				gchar	   *chan_str;
@@ -962,7 +987,6 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 					NULL
 				};
 
-				freq	 = tvb_get_letohs(tvb, offset);
 				flags	 = tvb_get_letohs(tvb, offset + 2);
 				chan_str = ieee80211_mhz_to_str(freq);
 				col_add_fstr(pinfo->cinfo,
@@ -1153,7 +1177,46 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 
 			mcs_known = tvb_get_guint8(tvb, offset);
 			mcs_flags = tvb_get_guint8(tvb, offset + 1);
-			mcs = tvb_get_guint8(tvb, offset + 2);
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_MCS) {
+				mcs = tvb_get_guint8(tvb, offset + 2);
+				phdr.presence_flags |= PHDR_802_11_HAS_MCS_INDEX;
+				phdr.mcs_index = mcs;
+			} else {
+				mcs = 0;
+				can_calculate_rate = FALSE;	/* no MCS index */
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_BW) {
+				phdr.presence_flags |= PHDR_802_11_HAS_BANDWIDTH;
+				phdr.bandwidth = (mcs_flags & IEEE80211_RADIOTAP_MCS_BW_MASK);
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_GI) {
+				gi_length = (mcs_flags & IEEE80211_RADIOTAP_MCS_SGI) ?
+				    1 : 0;
+				phdr.presence_flags |= PHDR_802_11_HAS_SHORT_GI;
+				phdr.short_gi = (gi_length == 0);
+			} else {
+				gi_length = 0;
+				can_calculate_rate = FALSE;	/* no GI width */
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_FMT) {
+				phdr.presence_flags |= PHDR_802_11_HAS_GREENFIELD;
+				phdr.greenfield = (mcs_flags & IEEE80211_RADIOTAP_MCS_FMT_GF) != 0;
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_FEC) {
+				phdr.presence_flags |= PHDR_802_11_HAS_LDPC;
+				phdr.ldpc = (mcs_flags & IEEE80211_RADIOTAP_MCS_FEC_LDPC) != 0;
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_STBC) {
+				phdr.presence_flags |= PHDR_802_11_HAS_STBC_STREAMS;
+				phdr.stbc_streams = (mcs_flags & IEEE80211_RADIOTAP_MCS_STBC_MASK) >> IEEE80211_RADIOTAP_MCS_STBC_SHIFT;
+			}
+			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_NESS) {
+				phdr.presence_flags |= PHDR_802_11_HAS_NESS;
+				/* This is stored a bit weirdly */
+				phdr.ness =
+				    ((mcs_known & IEEE80211_RADIOTAP_MCS_NESS_BIT1) >> 6) |
+				    ((mcs_flags & IEEE80211_RADIOTAP_MCS_NESS_BIT0) >> 7);
+			}
 
 			if (tree) {
 				proto_item *it;
@@ -1198,13 +1261,8 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 				can_calculate_rate = FALSE;	/* no bandwidth */
 			}
 			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_GI) {
-				gi_length = (mcs_flags & IEEE80211_RADIOTAP_MCS_SGI) ?
-				    1 : 0;
 				proto_tree_add_uint(mcs_tree, hf_radiotap_mcs_gi,
 							    tvb, offset + 1, 1, mcs_flags);
-			} else {
-				gi_length = 0;
-				can_calculate_rate = FALSE;	/* no GI width */
 			}
 			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_FMT) {
 				proto_tree_add_uint(mcs_tree, hf_radiotap_mcs_format,
@@ -1225,8 +1283,7 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 			if (mcs_known & IEEE80211_RADIOTAP_MCS_HAVE_MCS) {
 				proto_tree_add_uint(mcs_tree, hf_radiotap_mcs_index,
 							    tvb, offset + 2, 1, mcs);
-			} else
-				can_calculate_rate = FALSE;	/* no MCS index */
+			}
 
 			/*
 			 * If we have the MCS index, channel width, and
@@ -1516,8 +1573,7 @@ dissect_radiotap(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 	}
 
 	/* dissect the 802.11 packet next */
-	call_dissector_with_data((rflags & IEEE80211_RADIOTAP_F_DATAPAD) ?
-	    ieee80211_datapad_handle : ieee80211_handle, next_tvb, pinfo,
+	call_dissector_with_data(ieee80211_radio_handle, next_tvb, pinfo,
 	    tree, &phdr);
 
 	tap_queue_packet(radiotap_tap, pinfo, radiotap_info);
@@ -1991,6 +2047,11 @@ void proto_register_radiotap(void)
 		  FT_BOOLEAN, 8, TFS(&tfs_present_absent), IEEE80211_RADIOTAP_MCS_HAVE_BW,
 		  "Bandwidth information present", HFILL}},
 
+		{&hf_radiotap_mcs_have_index,
+		 {"MCS index", "radiotap.mcs.have_index",
+		  FT_BOOLEAN, 8, TFS(&tfs_present_absent), IEEE80211_RADIOTAP_MCS_HAVE_MCS,
+		  "MCS index information present", HFILL}},
+
 		{&hf_radiotap_mcs_have_gi,
 		 {"Guard interval", "radiotap.mcs.have_gi",
 		  FT_BOOLEAN, 8, TFS(&tfs_present_absent), IEEE80211_RADIOTAP_MCS_HAVE_GI,
@@ -2021,11 +2082,6 @@ void proto_register_radiotap(void)
 		  FT_BOOLEAN, 8, TFS(&tfs_1_0), IEEE80211_RADIOTAP_MCS_NESS_BIT1,
 		  "Bit 1 of number of extension spatial streams information", HFILL}},
 
-		{&hf_radiotap_mcs_have_index,
-		 {"MCS index", "radiotap.mcs.have_index",
-		  FT_BOOLEAN, 8, TFS(&tfs_present_absent), IEEE80211_RADIOTAP_MCS_HAVE_MCS,
-		  "MCS index information present", HFILL}},
-
 		{&hf_radiotap_mcs_bw,
 		 {"Bandwidth", "radiotap.mcs.bw",
 		  FT_UINT8, BASE_DEC, VALS(mcs_bandwidth),
@@ -2391,9 +2447,8 @@ void proto_reg_handoff_radiotap(void)
 {
 	dissector_handle_t radiotap_handle;
 
-	/* handle for 802.11 dissector */
-	ieee80211_handle = find_dissector("wlan");
-	ieee80211_datapad_handle = find_dissector("wlan_datapad");
+	/* handle for 802.11+radio information dissector */
+	ieee80211_radio_handle = find_dissector("wlan_radio");
 
 	radiotap_handle = find_dissector("radiotap");