amos-pro-bsdsocket-extension/API.md

8.2 KiB

BSD Socket Extension API

Most functions will return -2 if the bsdsocket.library is not open.


Setup

ADDR=Socket Library Open

Try to open bsdsocket.library version 4.

Returns
  • 0 if opening failed
  • Memory address of library on success
    • If needed, you'll be able to directly access library functions using this address.

Socket Library Close

Close bsdsocket.library. This is safe to call if the library is not open


RESULT=Socket Set Nonblocking(Socket, IsNonblocking BOOL)

Make a socket blocking (False, default), or nonblocking (True).

Returns
  • Result of IoctlSocket call.

RESULT=Socket Reuse Addr(Socket)

Make a listening socket reuse the address it's trying to bind to. You probably want to call this right before Socket Listen.

Returns
  • Result of setsockopt call.

Connections

SOCKET=Socket Create Inet Socket

Create a new Internet socket for reading or writing.

Returns
  • Socket number on success
  • -1 on failure

RESULT=Socket Connect(Socket to IPAddress$, Port)

Attempt to connect to a remote IP address.

Emulation vs. Physical/FPGA Amiga note

On emulated Amigas (FS-UAE) with emulated bsdsocket.library, a failure in Socket Connect due to giving the function a bad IP address allows you to reuse the socket. On real or FPGA-based Amiga running real TCP/IP stacks (MiamiDX, Roadshow), the socket will be made unusable and you'll need to Socket Close Socket and reopen the socket with whatever parameters necessary. Closing and opening bsdsocket.library has the same effect.

Always close and re-open a socket if you have any Socket Connect failure and any non-blocking polling loops time out!

Returns
  • 0 on connected
  • -1 on error
    • If your socket is non-blocking, you have to check the socket with Socket Select and Socket Getsockopt Int to see if the connection succeeded
  • -11 port out of range
  • -13 IP address has zero length

RESULT=Socket Reuse Addr(Socket)

Set a server socket to reuse an interface and port that had been used recently. You likely want this if you're building something that listens on a port for connections. This calls setsockopt() for you.

Returns

The result of calling setsockopt() while setting your socket to reuse addresses.


RESULT=Socket Bind(Socket to IPAddress, Port)

Attempt to bind a socket to a network interface. Use the string "IPADDR_ANY" for IPAddress to bind to all interfaces.

Returns
  • 0 on success
  • -1 on other error
  • -11 port out of range

RESULT=Socket Listen(Socket)

Start listening for connections.

Returns
  • 0 on success
  • -1 on failure

NEW_SOCKET=Socket Accept(Socket)

Get the socket that connected to this one. Wait for a connect if this socket is blocking.

Warning

If this socket is blocking (the default), you will likely get AMOS stuck in a state you can't recover from, due to how AMOS takes over system signals! Be sure to make your socket non-blocking and use Fdsets and Select!

Returns
  • The remote socket number on success
  • -1 on failure

RESULT=Socket Wait Async Reading(Socket, Wait_ms)

Wait the given number of milliseconds for the nonblocking socket to be ready for reading. Use on a listen socket to await new connections, or on a connected socket to await incoming data packets.

Returns
  • 0 on timeout.
  • -1 on error. Use Socket Errno for more detail.
  • 1 on success.

RESULT=Socket Wait Async Writing(Socket, Wait_ms)

Wait the given number of milliseconds for the nonblocking socket to be ready for writing. Use this when you're connecting to a remote server and want to know if the connection has been completed.

Returns
  • 0 on timeout.
  • -1 on error. Use Socket Errno for more detail.
  • -3 on the socket having an error.
    • If you're using this function to test for a successful connection and receive a -3, close and reopen the socket, otherwise subsequent checks will return 1.
  • 1 on success.

RESULT=Socket Set Timeout(Socket, Wait_ms)

Set a socket to timeout after Wait_ms milliseconds if reading or writing doesn't complete.

Returns
  • 0 on success
  • -1 on error

RESULT=Socket Close Socket(Socket)

Close a socket.

Returns
  • 0 on success
  • -1 on error

Data Transfers

SENT=Socket Send$(Socket, String$)

Send a string to a connected socket.

Bugs

For some reason, this command performs incorrectly when used in a Procedure to send a passed-in variable, and Varptr() is not called on the string variable to be sent beforehand within the procedure itself. I believe this is a bug in AMOS itself. You'll know you're having this issue if the byte count returned is abnormally high.

If you're using this in a Procedure, call Varptr() first:

Procedure SEND_STRING[SOCKET, S$]
  ' _shrug_
  _=Varptr(S$)

  BYTES=Socket Send$(SOCKET,S$)
End Proc
Returns
  • Number of characters sent
  • -1 on other error

SENT=Socket Send(Socket, Data Pointer, Length)

Send a block of data to a connected socket.

Returns
  • Number of characters sent
  • -1 on other error

DATA$=Socket Recv$(Socket, MaxLength)

Retrieve at most MaxLength bytes from Socket, and put them into a string. If Len(DATA$) < MaxLength, you've read the last bit of data from the socket.

Returns
  • String of data, which is blank if there is no more data.

LENGTH=Socket Recv(Socket to Dataptr, MaxLength)

Retrieve at most MaxLength bytes from Socket, and put them into the memory address at Dataptr.

Returns

  • Count of bytes read
  • -1 on error

Informational

HOST=Socket Get Host(Socket)

Get the IPv4 (Long) host value the given socket is using.

Returns
  • Host as a long value

PORT=Socket Get Port(Socket)

Get the 16-bit port (Word) value the given socket is using.

Returns
  • Port as a word value

RESULT$=Socket Inet Ntoa$(Host)

Turn a long Host address into a string.

Returns
  • IP address as string

RESULT=Socket Errno

Get the error from the last command. Note that this is not cleared on a successful command!

Returns

Error number from last call. Look in <sys/error.h> for more details.


RESULT=Socket Herrno

Get the error from the last DNS resolver command.

Returns

Resolver error number (h_errno) from last call.


RESULT$=Dns Get Address By Name$(Domain Name$)

Look up the first IP address associated with this hostname.

Warning

This is dependent on your stack's name resolution. If DNS lookups aren't working correctly, you may have to wait for the lookup to time out. There's no way to set this timeout, or cancel or override it via AMOS.

Returns

String with IP address, or blank string on error.


Low Level

RESULT=Socket Setsockopt Int(Socket, Option, Value)

Set a socket option. You probably want SO_REUSEADDR, which is Option=$4, and you want Value=True. Or, use Socket Reuse Addr().

Returns
  • Result of setsockopt call

RESULT=Socket Getsockopt Int(Socket, Option)

Get a socket option. You probably want SO_ERROR, which is Option=$1007, and it's what you check when you attempt a connection with a non-blocking socket.

Returns
  • Result of getsockopt call

ADDR=Socket Fdset Zero(fd_set)

Clear out the specified fd_set.

Returns
  • Address to that particular fd_set
  • -1 if fd_set out of range. You get 16 of them.

ADDR=Socket Fdset Set(fd_set, Socket to Value BOOL)

Set or clear a socket bit in an fd_set.

Returns
  • Address to that particular fd_set
  • -1 if fd_set is out of range or socket is out of range.

RESULT=Socket Fdset Is Set(fd_set, Socket)

See if the particular socket remained after a Socket Select call.

Returns
  • True or False if the socket is set or not

RESULT=Socket Select(Max Socket, Read fd_set, Write fd_set, Error fd_set, TimeoutMS)

Wait for the specified number of milliseconds. If any of the sockets in any of the fd_sets become interesting during that time, stop waiting, clear out the uninteresting sockets in the fd_sets, and return how many sockets were left.

Returns
  • 0 on timeout
  • -1 on error
  • Count of interesting sockets on success