Chapter 4. Socket Simulator - I/O
SOCTEST - USER'S GUIDE
In this chapter, it describes about the I/O function via socket.

To send or receive data, sets the following information to the parameters of system call.
With executing after selecting predetermined parameter, system call is called.

When succeeded (returned 0 or upper)

Received data could be saved. You can refer the data in Data Manager later. See Chapter 7. Data Manager for details.

When error occurred (returned -1)

Address

When using sendto(2) or sendmsg(2), specifies the destination address.
Regists the address in Address Manager beforehand. See Chapter 6. Address Manager for details.

When using recvfrom(2) or recvmsg(2), specifies whether gets remote address.

Message buffer

Specifies data content and data size if sending data, buffer size if receiving data.
The maximum size is limited to 64 KB in order to prevent an increase in packet charges due to erroneous operation.

Selects data content from the followings. When using a customized data, regists in Data Manager beforehand. See Chapter 7. Data Manager for details.

Data content	Details
Customized data	User can customize freely.
All "0" ascii string	00000000...
Continuous numeric ascii string	01234567890123456789...
Random numeric ascii string	Random of 0-9
Random alphabet & numeric ascii string	Random of 0-9a-zA-Z
Random printable ascii string	Random of 0-9a-zA-Z !"#$%&'()*+,-./:;<=>?@[\]^_`{\|}~
All 0 binary code	0x00 0x00 0x00 0x00 ...
All 1 binary code	0xff 0xff 0xff 0xff ...
Random binary code	Random of 0x00-0xff

Originally, if using sendmsg (2) and recvmsg (2) can be specified multiple data or buffer. [Note]
Originally, sendmsg(2) or recvmsg(2) can be specified multiple data / buffers.
However, in the current version, you can only specify a single data and buffer in this app.

Control messages

When using sendmsg(2), sends control messages as an ancillary data.
When using recvmsg(2), specifies the buffer size for an ancillary data.

Level Type	Description	Send	Recv
SOL_SOCKET SCM_RIGHTS	Sends / receives the list of file descriptors (32 bit integer) via UNIX domain socket.
SOL_SOCKET SCM_TIMESTAMP	Receives timestamp (timeval structure).
SOL_SOCKET SCM_CREDS	Sends / receives process credential information (cmsgcred structure data) via UNIX domain socket.
SOL_SOCKET SCM_TIMESTAMP_MONOTONIC	Receives monotonically increasing timestamp.
IPPROTO_IP IP_RECVOPTS	Receives all IP options.
IPPROTO_IP IP_RECVRETOPTS	Receives IP options for response.
IPPROTO_IP IP_RECVDSTADDR	Receives destination IP address.
IPPROTO_IP IP_RETOPTS	Gets / sets IP options (ip_opts structure data).
IPPROTO_IP IP_RECVIF	Receives interface information (sockaddr_dl structure data) which datagram is receibed.
IPPROTO_IP IP_RECVTTL	Receives TTL (8 bit integer).
IPPROTO_IP IP_PKTINFO	Gets pktinfo (ip_pktinfo structure data) on recv socket / Sets source on sent datagram.
IPPROTO_IP IP_RECVTOS	Receives TOS (8 bit integer).

Message flags

Specifies the I/O behavior with flags.
Specifies with the logical sum of 0 or more flags.
Please refer the man page or internet public site for the detail of each flags.

Flag	Description	Send	Recv	Msg
MSG_OOB	Sends OOB (out-of-band) data. / Requests receipt of OOB data. / Indicates receipt of OOB data.
MSG_DONTROUTE	Sends to hosts only on directly connected networks.
MSG_PEEK	Requests to return data without removing data from receive queue.
MSG_WAITALL	Requests that operation block until receiving full data.
MSG_TRUNC	Indicates that the trailing part of data was discarded because data was larger than buffer.
MSG_CTRUNC	Indicates that some control data were discarded because ancillary data buffer was lack.

Send: specifies flag with sendXXX(2)
Recv: specifies flag with recvXXX(2)
Msg: flag returned with recvmsg(2)