Chapter 1. Socket Simulator
SOCTEST - USER'S GUIDE

In this chapter, it describes about the function of Socket Simulator's initial view (the "Top View").

In this view, creates and deletes a socket. And, polls, lists sockets.

Creation a socket

With tapping socket, moves to the next view. You select protocol family, socket type, and protocol in the next view, then a new socket is created with calling socket(2).
The created sockets are listed in Top View.

[Note]
No upper limit on the number of sockets that can be created.

Deletion a socket

With swiping left a row, close(2) is called to close the socket, then removes from the list.

Polling for sockets

With pulling down Top View, you can poll the status for all sockets.
In this polling, it calls poll(2) with POLLIN|POLLPRI|POLLOUT as request events and 0 seconds as timeout.

Listing sockets

It describes how to confirm the information and the status of socket in the list.

Icon

It changes depending on the status of socket.

Icon		Description
Role		Server socket Socket is waiting a connection request with calling listen(2). Or, socket was created with accept(2).
Role		Client socket Other than those above.
I/O mode (*1)		Non-blocking mode The file status flag of socket was set to O_NONBLOCK with fcntl(2).
I/O mode (*1)		Blocking mode Other than those above.
Connection status (*2)		Not connected Status is Idle. Or, the socket is bound status with calling bind(2).
		Listening Waiting for connection request with calling listen(2).
		Connect in progress Waiting for completion of connection for the non-blocking socket.
		Connect error Error occurred in connection for the socket.
		Connected (in full duplex) Completion connect for the socket. Or, the socket was created with accept(2).
		Connected Receiver side of full duplex was shut down.
		Connected Sender side of full duplex was shut down.
		Disconnect All of full duplex were shut down.

*1 When the app setting DESCRIPTION is enabled, the icon of I/O mode is displayed.
*2 When the app setting AUTO MONITORING is enabled, the icon of connection status is displayed with SOCK_STREAM socket.

Socket address (Upper row)

If socket assigned an address, Src Address is displayed.
But, excepts a listening socket.

In Address, the pair of IP address and port (if PF_INET), or UNIX domain path (if PF_UNIX) is displayed.

Socket title

A title depending on the status of socket is displayed.

Title	Status
INET domain socket	Initial state of AF_INET socket
UNIX domain socket	Initial state of AF_UNIX socket
Dst Address	Socket is connected.
Src Address	Socket is listening. Or, SOCK_DGRAM socket is assinged an address.

Socket parameters (Lower row 1)

The following informaiton is displayed.
When the app setting DESCRIPTION is enabled, this row is displayed.

File discriptor number
Protocol family
Socket type
Protocol (except specifying default 0)

Socket connection status (Lower row 2)

Connection status of the socket are displayed. This status interlocks the above icon.
When the app setting AUTO MONITORING is enabled, this row is displayed with SOCK_STREAM socket.

Connection status	Icon	Description
Idle		Initial status.
Bound		An address is bound to the socket.
Listening		Waiting for connection requests.
Connect in progress		Waiting for completion of connecting.
Connect error		Error occurred in connecting process. The following error value is displayed as an additional information. Err#<errno number> <errno name>
Connected		Socket is connected.


Disconnect		Socket is disconnected.

Connection status transition diagram is as below.

TCP state (Lower row 3)

The state of TCP connection associated with a socket is displayed.
When the app setting AUTO MONITORING is enabled, this row is displayed with TCP socket (AF_INET socket of SOCK_STREAM type).

This state is displayed based on the values of parameter tcpi_state obtained TCP_CONNECTION_INFO option.
See RFC#793 or internet public site for details.

tcpi_state	State
0	CLOSED
1	LISTEN
2	SYN_SENT
3	SYN_RECEIVED
4	ESTABLISHED
5	CLOSE_WAIT
6	FIN_WAIT_1
7	CLOSING
8	LAST_ACK
9	FIN_WAIT_2
10	TIME_WAIT

TCP traffic (Lower rows 4 - 6)

The amount of incoming data and outgoing data in packet transfer via a socket are displayed.
When the app setting AUTO MONITORING is enabled, it is displayed with TCP socket other than CLOSED, LISTEN status.

The value of the following parameters obtained TCP_CONNECTION_INFO option is displayed.

Traffic	Parameter	Description
RX	tcpi_rxbytes tcpi_rxpackets	Data size in incoming traffic (bytes / packets)
TX	tcpi_txbytes tcpi_txpackets	Data size in outgoing traffic (bytes / packets)
Retransmit	tcpi_txretransmitbytes tcpi_txretransmitpackets	Retransmitted data size in outging traffic (bytes / packets)

TCP RTT (Lower row 7)

The RTT (milisecond accuracy) in TCP communication are displayed.
When the app setting AUTO MONITORING is enabled, it is displayed with TCP socket other than CLOSED, LISTEN status.

The value of the following parameters obtained TCP_CONNECTION_INFO option is displayed.

Round Trip	Parameter	Description
Average RTT	tcpi_srtt	Average time of RTT (seconds)
Recent RTT	tcpi_rttcur	Most recent time of RTT (seconds)

Events bitmask (Lower row 8)

The bit mask of response events by polling are displayed.
If there are some events, the corresponding event bit is highlighted.
This information is utilized due to confirm the presence of incoming data, error, etc.

[Note]
Three types of polling are available in this app.

polling for all sockets (See above)
polling with specifying request events and timeout value (See Chapter 2. Socket Simulator - Functions)
polling executed automatically when the app setting AUTO MONITORING is enabled (See Chapter 8. Menu)