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/* packet-hdcp.c
* Routines for HDCP dissection
* Copyright 2011-2014, 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
*/
/*
* This dissector supports HDCP (version 1) over I2C. For now, only the
* most common protocol messages are recognized.
*
* The specification of the version 1 protocol can be found at
* http://www.digital-cp.com/files/static_page_files/5C3DC13B-9F6B-D82E-D77D8ACA08A448BF/HDCP Specification Rev1_4.pdf
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/ptvcursor.h>
void proto_register_hdcp(void);
static int proto_hdcp;
static wmem_tree_t *transactions;
static int ett_hdcp;
static int hf_hdcp_reg;
static int hf_hdcp_resp_in;
static int hf_hdcp_resp_to;
static int hf_hdcp_a_ksv;
static int hf_hdcp_b_ksv;
static int hf_hdcp_an;
static int hf_hdcp_hdmi_reserved;
static int hf_hdcp_repeater;
static int hf_hdcp_ksv_fifo;
static int hf_hdcp_fast_trans;
static int hf_hdcp_features;
static int hf_hdcp_fast_reauth;
static int hf_hdcp_hdmi_mode;
static int hf_hdcp_max_casc_exc;
static int hf_hdcp_depth;
static int hf_hdcp_max_devs_exc;
static int hf_hdcp_downstream;
static int hf_hdcp_link_vfy;
#define REG_BKSV 0x0
#define REG_AKSV 0x10
#define REG_AN 0x18
#define REG_BCAPS 0x40
#define REG_BSTATUS 0x41
typedef struct _hdcp_transaction_t {
uint32_t rqst_frame;
uint32_t resp_frame;
uint8_t rqst_type;
} hdcp_transaction_t;
static const value_string hdcp_reg[] = {
{ REG_BKSV, "B_ksv" },
{ REG_AKSV, "A_ksv" },
{ REG_AN, "An" },
{ REG_BCAPS, "B_caps"},
{ REG_BSTATUS, "B_status"},
{ 0, NULL }
};
/* the input tvb contains an HDCP message without the leading address byte
(the address byte is handled by the HDMI dissector)
the caller must set the direction in pinfo */
static int
dissect_hdcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
uint8_t reg;
proto_item *pi;
ptvcursor_t *cursor;
proto_tree *hdcp_tree;
hdcp_transaction_t *hdcp_trans;
proto_item *it;
uint64_t a_ksv, b_ksv;
/* XXX check if the packet is really HDCP? */
col_set_str(pinfo->cinfo, COL_PROTOCOL, "HDCP");
col_clear(pinfo->cinfo, COL_INFO);
pi = proto_tree_add_protocol_format(tree, proto_hdcp,
tvb, 0, tvb_reported_length(tvb), "HDCP");
hdcp_tree = proto_item_add_subtree(pi, ett_hdcp);
cursor = ptvcursor_new(pinfo->pool, hdcp_tree, tvb, 0);
if (pinfo->p2p_dir==P2P_DIR_SENT) {
/* transmitter sends data to the receiver */
reg = tvb_get_uint8(tvb, ptvcursor_current_offset(cursor));
/* all values in HDCP are little endian */
ptvcursor_add(cursor, hf_hdcp_reg, 1, ENC_LITTLE_ENDIAN);
if (tvb_reported_length_remaining(tvb,
ptvcursor_current_offset(cursor)) == 0) {
/* transmitter requests the content of a register */
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "request %s",
val_to_str(reg, hdcp_reg, "unknown (0x%x)"));
if (PINFO_FD_VISITED(pinfo)) {
/* we've already dissected the receiver's response */
hdcp_trans = (hdcp_transaction_t *)wmem_tree_lookup32(
transactions, pinfo->num);
if (hdcp_trans && hdcp_trans->rqst_frame==pinfo->num &&
hdcp_trans->resp_frame!=0) {
it = proto_tree_add_uint_format(hdcp_tree, hf_hdcp_resp_in,
NULL, 0, 0, hdcp_trans->resp_frame,
"Request to get the content of register %s, "
"response in frame %d",
val_to_str_const(hdcp_trans->rqst_type,
hdcp_reg, "unknown (0x%x)"),
hdcp_trans->resp_frame);
proto_item_set_generated(it);
}
}
else {
/* we've not yet dissected the response */
hdcp_trans = wmem_new(wmem_file_scope(), hdcp_transaction_t);
hdcp_trans->rqst_frame = pinfo->num;
hdcp_trans->resp_frame = 0;
hdcp_trans->rqst_type = reg;
wmem_tree_insert32(transactions,
hdcp_trans->rqst_frame, (void *)hdcp_trans);
}
}
else {
/* transmitter actually sends protocol data */
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "send %s",
val_to_str(reg, hdcp_reg, "unknown (0x%x)"));
switch (reg) {
case REG_AKSV:
a_ksv = tvb_get_letoh40(tvb,
ptvcursor_current_offset(cursor));
proto_tree_add_uint64_format(hdcp_tree, hf_hdcp_a_ksv,
tvb, ptvcursor_current_offset(cursor), 5,
a_ksv, "A_ksv 0x%010" PRIx64, a_ksv);
ptvcursor_advance(cursor, 5);
break;
case REG_AN:
ptvcursor_add(cursor, hf_hdcp_an, 8, ENC_LITTLE_ENDIAN);
break;
default:
break;
}
}
}
else {
/* transmitter reads from receiver */
hdcp_trans = (hdcp_transaction_t *)wmem_tree_lookup32_le(
transactions, pinfo->num);
if (hdcp_trans) {
if (hdcp_trans->resp_frame==0) {
/* there's a pending request, this packet is the response */
hdcp_trans->resp_frame = pinfo->num;
}
if (hdcp_trans->resp_frame== pinfo->num) {
/* we found the request that corresponds to our response */
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "send %s",
val_to_str_const(hdcp_trans->rqst_type,
hdcp_reg, "unknown (0x%x)"));
it = proto_tree_add_uint_format(hdcp_tree, hf_hdcp_resp_to,
NULL, 0, 0, hdcp_trans->rqst_frame,
"Response to frame %d (content of register %s)",
hdcp_trans->rqst_frame,
val_to_str_const(hdcp_trans->rqst_type,
hdcp_reg, "unknown (0x%x)"));
proto_item_set_generated(it);
switch (hdcp_trans->rqst_type) {
case REG_BKSV:
b_ksv = tvb_get_letoh40(tvb,
ptvcursor_current_offset(cursor));
proto_tree_add_uint64_format(hdcp_tree, hf_hdcp_b_ksv,
tvb, ptvcursor_current_offset(cursor), 5,
b_ksv, "B_ksv 0x%010" PRIx64,
b_ksv);
ptvcursor_advance(cursor, 5);
break;
case REG_BCAPS:
ptvcursor_add_no_advance(cursor,
hf_hdcp_hdmi_reserved, 1, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_repeater, 1, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_ksv_fifo, 1, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_fast_trans, 1, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_features, 1, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_fast_reauth, 1, ENC_LITTLE_ENDIAN);
break;
case REG_BSTATUS:
ptvcursor_add_no_advance(cursor,
hf_hdcp_hdmi_mode, 2, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_max_casc_exc, 2, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_depth, 2, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_max_devs_exc, 2, ENC_LITTLE_ENDIAN);
ptvcursor_add_no_advance(cursor,
hf_hdcp_downstream, 2, ENC_LITTLE_ENDIAN);
break;
}
}
}
if (!hdcp_trans || hdcp_trans->resp_frame!=pinfo->num) {
/* the packet isn't a response to a request from the
* transmitter; it must be a link verification */
if (tvb_reported_length_remaining(
tvb, ptvcursor_current_offset(cursor)) == 2) {
col_append_sep_str(pinfo->cinfo, COL_INFO, NULL,
"send link verification Ri'");
ptvcursor_add_no_advance(cursor,
hf_hdcp_link_vfy, 2, ENC_LITTLE_ENDIAN);
}
}
}
ptvcursor_free(cursor);
return tvb_reported_length(tvb);
}
void
proto_register_hdcp(void)
{
static hf_register_info hf[] = {
{ &hf_hdcp_reg,
{ "Register offset", "hdcp.reg", FT_UINT8, BASE_HEX,
VALS(hdcp_reg), 0, NULL, HFILL } },
{ &hf_hdcp_resp_in,
{ "Response In", "hdcp.resp_in", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
"The response to this request is in this frame", HFILL }},
{ &hf_hdcp_resp_to,
{ "Response To", "hdcp.resp_to", FT_FRAMENUM, BASE_NONE, NULL, 0x0,
"This is the response to the request in this frame", HFILL }},
{ &hf_hdcp_a_ksv,
{ "Transmitter's key selection vector", "hdcp.a_ksv", FT_UINT40,
BASE_HEX, NULL, 0, NULL, HFILL } },
{ &hf_hdcp_b_ksv,
{ "Receiver's key selection vector", "hdcp.b_ksv", FT_UINT64,
BASE_HEX, NULL, 0, NULL, HFILL } },
{ &hf_hdcp_an,
{ "Random number for the session", "hdcp.an", FT_UINT64,
BASE_HEX, NULL, 0, NULL, HFILL } },
{ &hf_hdcp_hdmi_reserved,
{ "HDMI reserved", "hdcp.hdmi_reserved", FT_UINT8, BASE_DEC,
NULL, 0x80, NULL, HFILL } },
{ &hf_hdcp_repeater,
{ "Repeater", "hdcp.repeater", FT_UINT8, BASE_DEC,
NULL, 0x40, NULL, HFILL } },
{ &hf_hdcp_ksv_fifo,
{ "KSV fifo ready", "hdcp.ksv_fifo", FT_UINT8, BASE_DEC,
NULL, 0x20, NULL, HFILL } },
{ &hf_hdcp_fast_trans,
{ "Support for 400KHz transfers", "hdcp.fast_trans",
FT_UINT8, BASE_DEC, NULL, 0x10, NULL, HFILL } },
{ &hf_hdcp_features,
{ "Support for additional features", "hdcp.features",
FT_UINT8, BASE_DEC, NULL, 0x02, NULL, HFILL } },
{ &hf_hdcp_fast_reauth,
{ "Support for fast re-authentication", "hdcp.fast_reauth",
FT_UINT8, BASE_DEC, NULL, 0x01, NULL, HFILL } },
{ &hf_hdcp_hdmi_mode,
{ "HDMI mode", "hdcp.hdmi_mode",
FT_UINT16, BASE_DEC, NULL, 0x1000, NULL, HFILL } },
{ &hf_hdcp_max_casc_exc,
{ "Maximum cascading depth exceeded", "hdcp.max_casc_exc",
FT_UINT16, BASE_DEC, NULL, 0x0800, NULL, HFILL } },
{ &hf_hdcp_depth,
{ "Repeater cascade depth", "hdcp.depth",
FT_UINT16, BASE_DEC, NULL, 0x0700, NULL, HFILL } },
{ &hf_hdcp_max_devs_exc,
{ "Maximum number of devices exceeded", "hdcp.max_devs_exc",
FT_UINT16, BASE_DEC, NULL, 0x0080, NULL, HFILL } },
{ &hf_hdcp_downstream,
{ "Number of downstream receivers", "hdcp.downstream",
FT_UINT16, BASE_DEC, NULL, 0x007F, NULL, HFILL } },
{ &hf_hdcp_link_vfy,
{ "Link verification response Ri'", "hdcp.link_vfy",
FT_UINT16, BASE_HEX, NULL, 0, NULL, HFILL } }
};
static int *ett[] = {
&ett_hdcp
};
proto_hdcp = proto_register_protocol("High bandwidth Digital Content Protection", "HDCP", "hdcp");
proto_register_field_array(proto_hdcp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector("hdcp", dissect_hdcp, proto_hdcp);
transactions = wmem_tree_new_autoreset(wmem_epan_scope(), wmem_file_scope());
}
/*
* 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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