TCPLOG (JANUS DEFINE parameter)
TCPLOG filename — Log TCP activity to flatfile
TCPLOG is a parameter on JANUS DEFINE, which defines and sets characteristics of a Janus port.
A Janus Web Server port definition parameter, TCPLOG tells Janus Web Server to log in a sequential dataset all inbound and outbound TCP data transmitted for this port. The dataset name is specified as the value that follows the TCPLOG keyword.
The log file is opened and cleared when the associated Janus port is started, and it is closed when the port is stopped or if an error occurs writing data to the dataset.
The log data is written in variable length blocks. The first four bytes of a block contain the length of the block. Each block contains at least one record. No character translation or formatting is done for the actual TCP data. Since the blocks are standard variable length blocks, they all start with a Block Descriptor Word (BDW) which consists of a halfword block length followed by two bytes of zero.
The layout of the records in each block is described in detail below:
| Offset | Length | Type | Description |
|---|---|---|---|
| 0 | 2 | Unsigned binary | RDW (Record descriptor word): the length of the current record |
| 2 | 2 | Unused | Unused |
| 4 | 8 | Unsigned binary | Unique TCP connection number |
| 12 | 4 | Unsigned binary | Record number |
| 16 | 8 | Unsigned binary | Time of day in clock units |
| 24 | 4 | Unsigned binary | Remote IP address |
| 28 | 4 | Unsigned binary | Local IP address |
| 32 | 2 | Unsigned binary | Remote port number |
| 34 | 2 | Unsigned binary | Local port number |
| 36 | 1 | EBCDIC character | Direction: S (Sent) or R (Received) |
| 37 | 1 | Unused | Unused |
| 38 | 2 | Unsigned binary | Length of TCP data |
| 40 | v | Binary | Any TCP data |
The TCPLOG dataset cannot be shared by multiple Janus ports.
The TCPLOG parameter is valid only for WEBSERV ports.