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diff --git a/epan/dissectors/packet-dtcp-ip.c b/epan/dissectors/packet-dtcp-ip.c
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+/* packet-dtcp-ip.c
+ * Routines for DTCP-IP dissection
+ * (Digital Transmission Content Protection over IP)
+ *
+ * Copyright 2012, Martin Kaiser <martin@kaiser.cx>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+/*
+ * quote from www.dtcp.com:
+ * "DTCP is a method of protecting audio and audiovisual entertainment
+ * content on home and personal networks over highbandwidth bidirectional
+ * digital interfaces"
+ *
+ * this dissector supports DTCP on top of TCP/IP
+ * for now, only the AKE (authentication and key exchange)
+ * messages are implemented
+ *
+ * the dissector is based on the publicly available (informative) specifications
+ * obtained from http://www.dtcp.com/specifications.aspx
+ * (complete specifications are available only to licensees)
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+
+static int proto_dtcp_ip = -1;
+
+void proto_register_dtcp_ip(void);
+void proto_reg_handoff_dtcp_ip(void);
+
+static dissector_handle_t dtcp_ip_handle;
+
+static gint ett_dtcp_ip = -1;
+static gint ett_dtcp_ip_ctrl = -1;
+static gint ett_dtcp_ip_ake_procedure = -1;
+
+static int hf_dtcp_ip_type = -1;
+static int hf_dtcp_ip_length = -1;
+static int hf_dtcp_ip_ctype = -1;
+static int hf_dtcp_ip_category = -1;
+static int hf_dtcp_ip_ake_id = -1;
+static int hf_dtcp_ip_subfct = -1;
+static int hf_dtcp_ip_ake_procedure = -1;
+static int hf_dtcp_ip_ake_proc_full = -1;
+static int hf_dtcp_ip_ake_proc_ex_full = -1;
+static int hf_dtcp_ip_ake_xchg_key = -1;
+static int hf_dtcp_ip_subfct_dep = -1;
+static int hf_dtcp_ip_ake_label = -1;
+static int hf_dtcp_ip_number = -1;
+static int hf_dtcp_ip_status = -1;
+static int hf_dtcp_ip_ake_info = -1;
+
+#define CTRL_LEN 8 /* control block is 8 bytes long */
+
+/* these definitions are taken from the public DTCP specification
+ it sounds like the private version defines more subfunctions */
+static const value_string subfct[] = {
+ { 0x01, "challenge" },
+ { 0x02, "response" },
+ { 0x03, "exchange_key" },
+ { 0, NULL }
+};
+
+static int * const ake_procedure_fields[] = { /* must be int, not gint */
+ &hf_dtcp_ip_ake_proc_full,
+ &hf_dtcp_ip_ake_proc_ex_full,
+ NULL
+};
+
+/* only one bit may be set in exchange_key, we can use a value string */
+static const value_string xchg_key[] = {
+ { 0x00, "None" },
+ { 0x08, "Exchange key (K_X) for AES-128" },
+ { 0x20, "Session Exchange key (K_S) for AES-128" },
+ { 0x40, "Remote Exchange key (K_R) for AES-128" },
+ { 0, NULL }
+};
+
+static const value_string ctrl_status[] = {
+ { 0x0, "No error" },
+ { 0x1, "Support for no more authentication procedures is currently available" },
+ { 0x7, "Any other error" },
+ { 0xF, "No information" },
+ { 0, NULL }
+};
+
+
+/* check if the packet is actually DTCP-IP */
+static gboolean
+dtcp_ip_check_packet(tvbuff_t *tvb)
+{
+ guint offset = 0;
+ guint8 type;
+ guint16 length;
+
+ /* a minimum DTCP-IP AKE packet has Type (1 byte),
+ Length (2 bytes) and Control (8 bytes) */
+ if (tvb_reported_length(tvb) < 1+2+CTRL_LEN)
+ return FALSE;
+
+ type = tvb_get_guint8(tvb, offset);
+ /* all DTCP-IP AKE packets have type 1 */
+ if (type != 1)
+ return FALSE;
+ offset++;
+
+ /* length field is length of the control block +
+ length of ake_info */
+ length = tvb_get_ntohs(tvb, offset);
+ if (length < CTRL_LEN)
+ return FALSE;
+
+ return TRUE;
+}
+
+static int
+dissect_dtcp_ip(tvbuff_t *tvb, packet_info *pinfo,
+ proto_tree *tree, void *data _U_)
+{
+ guint offset = 0;
+ guint16 length;
+ proto_item *pi;
+ proto_tree *dtcp_ip_tree, *dtcp_ip_ctrl_tree;
+ guint8 subfct_val;
+ const gchar *subfct_str;
+ gint ake_info_len;
+
+
+ if (!dtcp_ip_check_packet(tvb))
+ return 0; /* not a DTCP-IP packet */
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "DTCP-IP");
+ col_clear(pinfo->cinfo, COL_INFO);
+
+ pi = proto_tree_add_protocol_format(tree, proto_dtcp_ip,
+ tvb, 0, -1, "DTCP-IP");
+ dtcp_ip_tree = proto_item_add_subtree(pi, ett_dtcp_ip);
+
+ proto_tree_add_item(dtcp_ip_tree, hf_dtcp_ip_type,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ length = tvb_get_ntohs(tvb, 1);
+ /* overall packet length is 1 byte for tag + 2 bytes for length field +
+ the value encoded in the length field */
+ proto_item_set_len(pi, 1+2+length);
+ proto_tree_add_item(dtcp_ip_tree, hf_dtcp_ip_length,
+ tvb, offset, 2, ENC_BIG_ENDIAN);
+ offset += 2;
+
+ dtcp_ip_ctrl_tree = proto_tree_add_subtree(dtcp_ip_tree,
+ tvb, offset, CTRL_LEN, ett_dtcp_ip_ctrl, NULL, "Control");
+
+ /* for now, we don't display the 4 reserved bits */
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_ctype,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_category,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_ake_id,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ subfct_val = tvb_get_guint8(tvb, offset);
+ subfct_str = val_to_str_const(subfct_val, subfct, "unknown");
+ col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL,
+ "%s (0x%x)", subfct_str, subfct_val);
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_subfct,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_bitmask(dtcp_ip_ctrl_tree, tvb, offset,
+ hf_dtcp_ip_ake_procedure, ett_dtcp_ip_ake_procedure,
+ ake_procedure_fields, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_ake_xchg_key,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_subfct_dep,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_ake_label,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_number,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ proto_tree_add_item(dtcp_ip_ctrl_tree, hf_dtcp_ip_status,
+ tvb, offset, 1, ENC_BIG_ENDIAN);
+ offset++;
+
+ ake_info_len = length-CTRL_LEN;
+ if (ake_info_len > 0) {
+ proto_tree_add_item(dtcp_ip_tree, hf_dtcp_ip_ake_info,
+ tvb, offset, ake_info_len, ENC_NA);
+ offset += (guint)ake_info_len;
+ }
+
+ return offset;
+}
+
+
+void
+proto_register_dtcp_ip(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_dtcp_ip_type,
+ { "Type", "dtcp-ip.type", FT_UINT8, BASE_HEX,
+ NULL, 0, NULL, HFILL } },
+ { &hf_dtcp_ip_length,
+ { "Length", "dtcp-ip.length", FT_UINT16, BASE_DEC,
+ NULL, 0, NULL, HFILL } },
+ /* it seems that / is not allowed in a filter name ... */
+ { &hf_dtcp_ip_ctype,
+ { "ctype/response", "dtcp-ip.ctrl.ctype_response", FT_UINT8,
+ BASE_HEX, NULL, 0x0F, NULL, HFILL } },
+ { &hf_dtcp_ip_category,
+ { "Category", "dtcp-ip.ctrl.category", FT_UINT8, BASE_HEX,
+ NULL, 0xF0, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_id,
+ { "AKE_ID", "dtcp-ip.ctrl.ake_id", FT_UINT8, BASE_HEX,
+ NULL, 0x0F, NULL, HFILL } },
+ { &hf_dtcp_ip_subfct,
+ { "Subfunction", "dtcp-ip.ctrl.subfunction", FT_UINT8, BASE_HEX,
+ VALS(subfct), 0, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_procedure,
+ { "AKE_procedure", "dtcp-ip.ctrl.ake_procedure", FT_UINT8,
+ BASE_HEX, NULL, 0, NULL, HFILL } },
+ /* 8 is the bit witdh of the field */
+ { &hf_dtcp_ip_ake_proc_full,
+ { "Full Authentication procedure",
+ "dtcp-ip.ctrl.ake_procedure.full_auth", FT_BOOLEAN, 8,
+ NULL, 0x04, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_proc_ex_full,
+ { "Extended Full Authentication procedure",
+ "dtcp-ip.ctrl.ake_procedure.ex_full_auth", FT_BOOLEAN, 8,
+ NULL, 0x08, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_xchg_key,
+ { "exchange_key", "dtcp-ip.ctrl.exchange_key", FT_UINT8, BASE_HEX,
+ VALS(xchg_key), 0, NULL, HFILL } },
+ { &hf_dtcp_ip_subfct_dep,
+ { "subfunction_dependent", "dtcp-ip.ctrl.subfunction_dependent",
+ FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_label,
+ { "AKE_label", "dtcp-ip.ctrl.ake_label", FT_UINT8, BASE_HEX,
+ NULL, 0, NULL, HFILL } },
+ { &hf_dtcp_ip_number,
+ { "number", "dtcp-ip.ctrl.number", FT_UINT8, BASE_HEX,
+ NULL, 0xF0, NULL, HFILL } },
+ { &hf_dtcp_ip_status,
+ { "Status", "dtcp-ip.ctrl.status", FT_UINT8, BASE_HEX,
+ VALS(ctrl_status), 0x0F, NULL, HFILL } },
+ { &hf_dtcp_ip_ake_info,
+ { "AKE_Info", "dtcp-ip.ake_info", FT_BYTES, BASE_NONE,
+ NULL, 0, NULL, HFILL } }
+ };
+
+ static gint *ett[] = {
+ &ett_dtcp_ip,
+ &ett_dtcp_ip_ctrl,
+ &ett_dtcp_ip_ake_procedure
+ };
+
+ proto_dtcp_ip = proto_register_protocol("Digital Transmission Content Protection over IP", "DTCP-IP", "dtcp-ip");
+
+ proto_register_field_array(proto_dtcp_ip, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ dtcp_ip_handle = register_dissector("dtcp-ip", dissect_dtcp_ip, proto_dtcp_ip);
+}
+
+void
+proto_reg_handoff_dtcp_ip(void)
+{
+ dissector_add_for_decode_as_with_preference("tcp.port", dtcp_ip_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:
+ */
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