Don't walk the entire protocol tree to extract the value of one field.

Instead, prime the epan_dissect_t's tree to look for rtp.ssrc, and
extract that value with proto_get_finfo_ptr_array().

Also, have the filter used to check whether the packet is a candidate
for RTP analysis to check for RTPv2 (and add a check for IPv4 or IPv6
back to the Qt version), and get rid of an unnecessary extra level of
indirection for that string.

In the Qt version, if findStreams() set the error string, don't
overwrite it with a "No streams found." indication, and fix error
handling for the "filter didn't compile" case.

Change-Id: I09d0ea37ccd4806d99e3b6394f2a8a376e974705
Reviewed-on: https://code.wireshark.org/review/13045
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 21 insertions, 81 deletions

diff --git a/ui/gtk/rtp_analysis.c b/ui/gtk/rtp_analysis.c
index 846635e206..2815e73d88 100644
--- a/ui/gtk/rtp_analysis.c
+++ b/ui/gtk/rtp_analysis.c
@@ -3719,75 +3719,6 @@ create_rtp_dialog(user_data_t* user_data)
 
 
 /****************************************************************************/
-static gboolean
-process_node(proto_node *ptree_node, header_field_info *hfinformation,
-		      const gchar* proto_field, guint32* p_result)
-{
-	field_info         *finfo;
-	proto_node         *proto_sibling_node;
-	header_field_info  *hfssrc;
-	ipv4_addr_and_mask *ipv4;
-
-	finfo = PNODE_FINFO(ptree_node);
-
-	/* Caller passed top of the protocol tree. Expected child node */
-	g_assert(finfo);
-
-	if (hfinformation == (finfo->hfinfo)) {
-		hfssrc = proto_registrar_get_byname(proto_field);
-		if (hfssrc == NULL)
-			return FALSE;
-		for (ptree_node = ptree_node->first_child;
-		     ptree_node != NULL;
-		     ptree_node = ptree_node->next) {
-			finfo = PNODE_FINFO(ptree_node);
-			if (hfssrc == finfo->hfinfo) {
-				if (hfinformation->type == FT_IPv4) {
-					ipv4 = (ipv4_addr_and_mask *)fvalue_get(&finfo->value);
-					*p_result = ipv4_get_net_order_addr(ipv4);
-				}
-				else {
-					*p_result = fvalue_get_uinteger(&finfo->value);
-				}
-				return TRUE;
-			}
-		}
-		if (!ptree_node)
-			return FALSE;
-	}
-
-	proto_sibling_node = ptree_node->next;
-
-	if (proto_sibling_node) {
-		return process_node(proto_sibling_node, hfinformation, proto_field, p_result);
-	}
-	else
-	return FALSE;
-}
-
-/****************************************************************************/
-static gboolean
-get_int_value_from_proto_tree(proto_tree  *protocol_tree,
-			      const gchar *proto_name,
-			      const gchar *proto_field,
-			      guint32     *p_result)
-{
-	proto_node	  *ptree_node;
-	header_field_info *hfinformation;
-
-	hfinformation = proto_registrar_get_byname(proto_name);
-	if (hfinformation == NULL)
-		return FALSE;
-
-	ptree_node = ((proto_node *)protocol_tree)->first_child;
-	if (!ptree_node)
-		return FALSE;
-
-	return process_node(ptree_node, hfinformation, proto_field, p_result);
-}
-
-
-/****************************************************************************/
 void
 rtp_analysis(address *src_fwd,
 	     guint32  port_src_fwd,
@@ -3921,9 +3852,9 @@ rtp_analysis_cb(GtkAction *action _U_, gpointer user_data _U_)
 	address	      dst_rev;
 	guint32	      port_dst_rev;
 	guint32	      ssrc_rev	    = 0;
-	unsigned int  version_fwd;
+	GPtrArray    *gp;
 
-	const gchar  *filter_text = "rtp && rtp.version && rtp.ssrc && (ip || ipv6)";
+	const gchar  filter_text[] = "rtp && rtp.version == 2 && rtp.ssrc && (ip || ipv6)";
 	dfilter_t    *sfcode;
 	gchar        *err_msg;
 	capture_file *cf;
@@ -3932,8 +3863,16 @@ rtp_analysis_cb(GtkAction *action _U_, gpointer user_data _U_)
 	GList	     *filtered_list = NULL;
 	guint	      nfound;
 	epan_dissect_t	   edt;
+	int	      hfid_rtp_ssrc;
 	rtp_stream_info_t *strinfo;
 
+	/* Try to get the hfid for "rtp.ssrc". */
+	hfid_rtp_ssrc = proto_registrar_get_id_byname("rtp.ssrc");
+	if (hfid_rtp_ssrc == -1) {
+		simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "There is no \"rtp.ssrc\" field in this version of Wireshark.");
+		return;
+	}
+
 	/* Try to compile the filter. */
 	if (!dfilter_compile(filter_text, &sfcode, &err_msg)) {
 		simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK, "%s", err_msg);
@@ -3953,13 +3892,17 @@ rtp_analysis_cb(GtkAction *action _U_, gpointer user_data _U_)
 		return;	/* error reading the record */
 	epan_dissect_init(&edt, cf->epan, TRUE, FALSE);
 	epan_dissect_prime_dfilter(&edt, sfcode);
+	epan_dissect_prime_hfid(&edt, hfid_rtp_ssrc);
 	epan_dissect_run(&edt, cf->cd_t, &cf->phdr, frame_tvbuff_new_buffer(fdata, &cf->buf), fdata, NULL);
 
-	/* if it is not an rtp packet, show the rtpstream dialog */
+	/*
+	 * Packet must be an RTPv2 packet with an SSRC; we use the filter to
+	 * check.
+	 */
 	if (!dfilter_apply_edt(sfcode, &edt)) {
 		epan_dissect_cleanup(&edt);
 		simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
-		    "Please select an RTP packet.");
+		    "Please select an RTPv2 packet with an SSID.");
 		return;
 	}
 
@@ -3975,19 +3918,16 @@ rtp_analysis_cb(GtkAction *action _U_, gpointer user_data _U_)
 	port_src_rev = edt.pi.destport;
 	port_dst_rev = edt.pi.srcport;
 
-	/* check if it is RTP Version 2 */
-	if (!get_int_value_from_proto_tree(edt.tree, "rtp", "rtp.version", &version_fwd) || version_fwd != 2) {
-		simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
-			      "Only RTP version 2 is supported.");
-		return;
-	}
-
 	/* now we need the SSRC value of the current frame */
-	if (!get_int_value_from_proto_tree(edt.tree, "rtp", "rtp.ssrc", &ssrc_fwd)) {
+	gp = proto_get_finfo_ptr_array(edt.tree, hfid_rtp_ssrc);
+	if (gp == NULL || gp->len == 0) {
+		/* XXX - should not happen, as the filter inculdes rtp.ssrc */
+		epan_dissect_cleanup(&edt);
 		simple_dialog(ESD_TYPE_ERROR, ESD_BTN_OK,
 		    "SSRC value not found.");
 		return;
 	}
+	ssrc_fwd = fvalue_get_uinteger(&((field_info *)gp->pdata[0])->value);
 
 	/* Scan for rtpstream */
 	rtpstream_scan(rtpstream_dlg_get_tapinfo(), &cfile, NULL);