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Extended Network Trace

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Introduction

The extended network trace allows the user to send or truncate network trace messages that are larger than the normal maximum size of a DLT message. This interface will be enabled if following calls are supported on the target:

  • mq_open
  • mq_close
  • mq_unlink
  • mq_send
  • mq_receive

Protocol

When truncation of messages is allowed, the truncated messages will be wrapped into a special message which indicates that a network trace message was truncated and what was the original size of the message.

Segmented messages are sent in multiple packages. The package stream is prepended with a start message indicating which contains a unique handle for this stream, size of data to follow, count of segments to follow and segment size.

Each segment contains the stream handle, segment sequence number, the data and data length.

Finally after sending all the data segments, one more packet is sent to indicate the end of the stream.

Truncated package

Truncated message can be sent using the following function:

int dlt_user_trace_network_truncated(DltContext *handle, DltNetworkTraceType nw_trace_type, uint16_t header_len, void *header, uint16_t payload_len, void *payload, int allow_truncate)

This will send a packet in the following format:

Value Description Type
NWTR Package identifier STRING
header nw_trace header and it's length RAW
size Original size of the message UINT
payload The truncated nw_trace payload RAW

Segmented messages

User can send a segmented network trace message asynchronously using:

void dlt_user_trace_network_segmented(DltContext *handle, DltNetworkTraceType nw_trace_type, uint16_t header_len, void *header, uint16_t payload_len, void *payload)

This will start a background thread and return immediately.

User can also send all the required packages one by one using:

int dlt_user_trace_network_segmented_start(unsigned int *id, DltContext *handle, DltNetworkTraceType nw_trace_type, uint16_t header_len, void *header, uint16_t payload_len)

int dlt_user_trace_network_segmented_segment(int id, DltContext *handle, DltNetworkTraceType nw_trace_type, int sequence, uint16_t payload_len, void *payload)

int dlt_user_trace_network_segmented_end(int id, DltContext *handle, DltNetworkTraceType nw_trace_type)

NOTE: It is not recommended to use these functions unless you really have to.

Segmented start packet

The first packet in the stream is the header:

Value Description Type
NWST Package identifier STRING
streamhandle Unique identifier for all packages in the stream UINT
header nw_trace header and it's length RAW
payloadsize Size of the complete payload in this stream UINT
segmentcount Number of segments to follow UINT
segmentlen Size of one segment UINT

Data segment

After the header, follows a stream of data segments.

Value Description Type
NWCH Package identifier STRING
streamhandle Unique identifier for all packages in the stream UINT
sequence Sequence number of this segment UINT
data One segment of the original nw_trace RAW

End packet

After all the segments have been sent, an End identifier is sent.

Value Description Type
NWEN Package identifier STRING
streamhandle Unique identifier for all packages in the stream UINT

Author

Lassi Marttala <Lassi.LM.Marttala (at) partner (dot) bmw (dot) de>

COPYRIGHT

Copyright (C) 2011 - 2015 BMW AG. License MPL-2.0: Mozilla Public License version 2.0 http://mozilla.org/MPL/2.0/.