DisplayPort AUX channel protocol dissector

Dissector for the VESA DisplayPort AUX channel protocol.

Bug: 14651
Change-Id: I5c0c7668bda969086d9d6e5069aad87e929f6340
Reviewed-on: https://code.wireshark.org/review/27311
Reviewed-by: Dario Lombardo <lomato@gmail.com>
Petri-Dish: Dario Lombardo <lomato@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 207 insertions, 0 deletions

diff --git a/epan/dissectors/packet-dpauxmon.c b/epan/dissectors/packet-dpauxmon.c
new file mode 100644
index 0000000000..13bba1daa0
--- /dev/null
+++ b/epan/dissectors/packet-dpauxmon.c
@@ -0,0 +1,207 @@
+/* packet-dpauxmon.c
+ * Routines for DisplayPort AUX-Channel monitor dissection
+ * Copyright 2018, Dirk Eibach, Guntermann & Drunck GmbH <dirk.eibach@gdsys.cc>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <config.h>
+#include <conversation.h>
+
+#include "packet-dpaux.h"
+
+#include <epan/packet.h>
+#include <epan/proto_data.h>
+
+enum {
+    DPAUXMON_DATA = 0x00,
+    DPAUXMON_DATA_END = 0x01,
+    DPAUXMON_EVENT = 0x02,
+    DPAUXMON_START = 0x03,
+    DPAUXMON_STOP = 0x04,
+    DPAUXMON_TS_OVERFLOW = 0x84,
+};
+
+void proto_reg_handoff_dpauxmon(void);
+void proto_register_dpauxmon(void);
+
+static dissector_handle_t dpaux_handle;
+
+/* Initialize the protocol and registered fields */
+static int proto_dpauxmon = -1;
+
+static int hf_packet_type = -1;
+static int hf_origin = -1;
+static int hf_inputs = -1;
+static int hf_hpd = -1;
+static int hf_in0 = -1;
+static int hf_in1 = -1;
+static int hf_in2 = -1;
+
+static const int *input_fields[] = {
+    &hf_hpd,
+    &hf_in0,
+    &hf_in1,
+    &hf_in2,
+    NULL
+};
+
+/* Initialize the subtree pointers */
+static gint ett_dpauxmon = -1;
+
+static int
+dissect_dpauxmon(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+        void *data _U_)
+{
+    proto_item *ti;
+    proto_tree *dpauxmon_tree;
+    guint8 packet_type = tvb_get_guint8(tvb, 0);
+
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "dpauxmon");
+    col_set_str(pinfo->cinfo, COL_INFO, "DisplayPort AUX channel");
+    col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A");
+    col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Internal");
+
+    /* create display subtree for the protocol */
+    ti = proto_tree_add_item(tree, proto_dpauxmon, tvb, 0, -1, ENC_NA);
+
+    dpauxmon_tree = proto_item_add_subtree(ti, ett_dpauxmon);
+
+    proto_tree_add_uint(dpauxmon_tree, hf_packet_type, tvb, 0, 1, packet_type);
+
+    switch (packet_type) {
+    case DPAUXMON_DATA: {
+        struct dpaux_info *dpaux_info = (struct dpaux_info*)
+            wmem_alloc(wmem_file_scope(), sizeof(struct dpaux_info));
+
+        dpaux_info->from_source = tvb_get_guint8(tvb, 1);
+        p_add_proto_data(wmem_file_scope(), pinfo, proto_dpaux, 0, dpaux_info);
+        proto_tree_add_uint(dpauxmon_tree, hf_origin, tvb, 1, 1,
+                            dpaux_info->from_source);
+
+        call_dissector(dpaux_handle, tvb_new_subset_remaining(tvb, 2),
+                 pinfo, dpauxmon_tree);
+        break;
+        }
+    case DPAUXMON_EVENT:
+    case DPAUXMON_START:
+        col_set_str(pinfo->cinfo, COL_INFO,
+                    (packet_type == DPAUXMON_START) ? "Start" : "Input changed");
+        proto_tree_add_bitmask(dpauxmon_tree, tvb, 1, hf_inputs, 0, input_fields,
+                               ENC_BIG_ENDIAN);
+        break;
+    case DPAUXMON_STOP:
+        col_set_str(pinfo->cinfo, COL_INFO, "Stop");
+        break;
+    case DPAUXMON_TS_OVERFLOW:
+        col_set_str(pinfo->cinfo, COL_INFO, "Timestamp overflow");
+        break;
+    };
+
+    return tvb_captured_length(tvb);
+}
+
+void
+proto_register_dpauxmon(void)
+{
+    static const value_string convert_packet_type[] = {
+        { DPAUXMON_DATA, "Data" },
+        { DPAUXMON_EVENT, "Event" },
+        { DPAUXMON_START, "Start" },
+        { DPAUXMON_STOP, "Stop" },
+        { DPAUXMON_TS_OVERFLOW, "Timestamp Overflow" },
+        { 0, NULL }
+    };
+
+    static const value_string convert_origin[] = {
+        { 0, "Sink" },
+        { 1, "Source" },
+        { 0, NULL }
+    };
+
+    /* Setup protocol subtree array */
+    static gint *ett[] = {
+        &ett_dpauxmon
+    };
+
+    /* Setup list of header fields  See Section 1.5 of README.dissector for
+     * details. */
+    static hf_register_info hf[] = {
+        { &hf_packet_type,
+          { "Packet Type", "dpauxmon.packet_type",
+            FT_UINT8, BASE_DEC, VALS(convert_packet_type), 0,
+            NULL, HFILL }
+        },
+        { &hf_origin,
+          { "Origin", "dpauxmon.origin",
+            FT_UINT8, BASE_DEC, VALS(convert_origin), 0,
+            NULL, HFILL }
+        },
+        { &hf_inputs,
+          { "Inputs", "dpauxmon.inputs",
+            FT_UINT8, BASE_HEX, NULL, 0,
+            NULL, HFILL }
+        },
+        { &hf_hpd,
+          { "Hotplug Detect", "dpauxmon.hpd",
+            FT_BOOLEAN, 4, NULL, 0x01,
+            NULL, HFILL }
+        },
+        { &hf_in0,
+          { "IN0", "dpauxmon.in0",
+            FT_BOOLEAN, 4, NULL, 0x02,
+            NULL, HFILL }
+        },
+        { &hf_in1,
+          { "IN1", "dpauxmon.in1",
+            FT_BOOLEAN, 4, NULL, 0x04,
+            NULL, HFILL }
+        },
+        { &hf_in2,
+          { "IN2", "dpauxmon.in2",
+            FT_BOOLEAN, 4, NULL, 0x08,
+            NULL, HFILL }
+        },
+    };
+
+    /* Register the protocol name and description */
+    proto_dpauxmon = proto_register_protocol("DPAUXMON DisplayPort AUX channel monitor",
+            "DPAUXMON", "dpauxmon");
+    proto_register_field_array(proto_dpauxmon, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_dpauxmon(void)
+{
+    static gboolean initialized = FALSE;
+    static dissector_handle_t dpauxmon_handle;
+
+    dpaux_handle = find_dissector_add_dependency("dpaux", proto_dpauxmon);
+
+    if (!initialized) {
+        dpauxmon_handle = create_dissector_handle(dissect_dpauxmon, proto_dpauxmon);
+        initialized = TRUE;
+    } else {
+        dissector_delete_uint("wtap_encap", WTAP_ENCAP_DPAUXMON, dpauxmon_handle);
+    }
+
+    dissector_add_uint("wtap_encap", WTAP_ENCAP_DPAUXMON, dpauxmon_handle);
+}
+
+/*
+ * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */