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Bluetooth: nordic: Calculate packet time for LE Coded PHY packets 

Calculate the packet time of an LE Coded PHY using both S8 and S2 coding.
The First part of the packet is always sent in S8 coding. And the CI flag
tells which coding rate is used for FEC block 2.

Change-Id: I7f0ad74b3e30ffecade59b6d0c5965bfc634531f
Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>
Reviewed-on: https://code.wireshark.org/review/36788
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Joakim Andersson 2020-04-11 19:10:39 +02:00 committed by Anders Broman
parent 8af333af1d
commit 24d7323eaf
1 changed files with 28 additions and 3 deletions
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31
epan/dissectors/packet-nordic_ble.c
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@ -197,9 +197,17 @@
#define US_PER_BYTE_1M_PHY 8
#define US_PER_BYTE_2M_PHY 4
#define US_PER_BYTE_CODED_PHY_S8 64
#define US_PER_BYTE_CODED_PHY_S2 16
#define PREAMBLE_LEN_1M_PHY 1
#define PREAMBLE_LEN_2M_PHY 2
/* Preamble + Access Address + CI + TERM1 */
#define FEC1_BLOCK_S8_US (80 + 256 + 16 + 24)
#define TERM2_S8_US 24
#define TERM2_S2_US 6
void proto_reg_handoff_nordic_ble(void);
void proto_register_nordic_ble(void);
@ -276,6 +284,9 @@ static const value_string le_phys[] =
{ 0, NULL }
};
#define CI_S8 0
#define CI_S2 1
static const value_string le_aux_ext_adv[] = {
{ 0, "AUX_ADV_IND" },
{ 1, "AUX_CHAIN_IND" },
@ -422,7 +433,7 @@ dissect_flags(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree,
return offset;
}
static guint16 packet_time_get(nordic_ble_context_t *nordic_ble_context)
static guint16 packet_time_get(nordic_ble_context_t *nordic_ble_context, guint8 ci)
{
/* Calculate packet time according to this packets PHY */
guint16 ble_payload_length = nordic_ble_context->payload_length - nordic_ble_context->event_packet_length;
@ -432,6 +443,19 @@ static guint16 packet_time_get(nordic_ble_context_t *nordic_ble_context)
return US_PER_BYTE_1M_PHY * (PREAMBLE_LEN_1M_PHY + ble_payload_length);
case LE_2M_PHY:
return US_PER_BYTE_2M_PHY * (PREAMBLE_LEN_2M_PHY + ble_payload_length);
case LE_CODED_PHY:
{
/* Subtract Access address and CI */
guint16 fec2_block_len = ble_payload_length - 4 - 1;
switch (ci) {
case CI_S8:
return FEC1_BLOCK_S8_US + fec2_block_len * US_PER_BYTE_CODED_PHY_S8 + TERM2_S8_US;
case CI_S2:
return FEC1_BLOCK_S8_US + fec2_block_len * US_PER_BYTE_CODED_PHY_S2 + TERM2_S2_US;
}
}
/* Fallthrough */
default:
return 0; /* Unknown */
}
@ -463,7 +487,7 @@ dissect_ble_delta_time(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tre
}
offset += 4;
packet_time = packet_time_get(nordic_ble_context);
packet_time = packet_time_get(nordic_ble_context, 0 /* This version never supported Coded PHY */);
pi = proto_tree_add_uint(tree, hf_nordic_ble_packet_time, tvb, offset, 4, packet_time);
proto_item_set_generated(pi);
@ -507,7 +531,8 @@ dissect_ble_timestamp(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree
last_packet_start_time = saved_packet_times->packet_start_time;
}
packet_time = packet_time_get(nordic_ble_context);
guint8 ci = tvb_get_guint8(tvb, offset + 4 + 4);
packet_time = packet_time_get(nordic_ble_context, ci);
item = proto_tree_add_uint(tree, hf_nordic_ble_packet_time, tvb, offset, 4, packet_time);
proto_item_set_generated(item);