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267 | --
-- Author: Brent Seidel
-- Date: 31-Jul-2024
--
-- This file is part of SimCPU.
-- SimCPU is free software: you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation, either version 3 of the License, or (at your
-- option) any later version.
--
-- SimCPU is distributed in the hope that it will be useful, but
-- WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
-- Public License for more details.
--
-- You should have received a copy of the GNU General Public License along
-- with SimCPU. If not, see <https://www.gnu.org/licenses/>.--
--
with Ada.Streams;
use type Ada.Streams.Stream_Element_Offset;
use type Ada.Streams.Stream_Element;
with Ada.Text_IO;
with Ada.Exceptions;
package body BBS.Sim_CPU.serial.telnet is
-- ----------------------------------------------------------------------
-- Telnet device actions
--
-- Set device port and do the network initialiation. This must be
-- done only once before using the device.
--
procedure init(self : in out tel_tty; ptr : telnet_access; port : GNAT.Sockets.Port_Type) is
begin
self.T.start(ptr, port, self.host);
end;
--
-- Set which exception to use
--
procedure setException(self : in out tel_tty; except : long) is
begin
self.int_code := except;
end;
--
-- Write to a port address.
-- If nothing is connected, the characters are just dropped.
--
overriding
procedure write(self : in out tel_tty; addr : addr_bus; data : data_bus) is
begin
if (addr = (self.base + 1)) and self.connected then
self.T.write(Character'Val(Integer(data and 16#FF#)));
elsif addr = self.base then
self.int_e := (data and 4) /= 0;
if (data and 8) /= 0 then -- Reset command.
self.ready := False;
self.char := Character'Val(0);
end if;
end if;
exception
when e : others =>
Ada.Text_IO.Put_Line("Exception occured while trying to write to console.");
Ada.Text_IO.Put_Line(" Name: " & Ada.Exceptions.Exception_Name(e));
Ada.Text_IO.Put_Line(" Msg: " & Ada.Exceptions.Exception_Message(e));
end;
--
-- Read from a port address
--
overriding
function read(self : in out tel_tty; addr : addr_bus) return data_bus is
begin
if addr = (self.base + 1) then
self.ready := False;
-- Ada.Text_IO.Put_Line("TTY: Returning character code " & toHex(byte(data_bus(Character'Pos(self.char)) and 16#FF#)));
return data_bus(Character'Pos(self.char));
elsif addr = self.base then
return 0 +
(if self.ready then 1 else 0) +
(if self.connected then 2 else 0) +
(if self.int_e then 4 else 0);
end if;
return 0;
end;
--
-- Get the base address
--
overriding
function getBase(self : in out tel_tty) return addr_bus is
begin
return self.base;
end;
--
-- Set the base address
--
overriding
procedure setBase(self : in out tel_tty; base : addr_bus) is
begin
self.base := base;
end;
--
-- Set the owner (used mainly for DMA and interrupts)
--
overriding
procedure setOwner(self : in out tel_tty; owner : sim_access) is
begin
self.host := owner;
end;
--
-- Close the network connection and halt the tasks.
--
procedure shutdown(self : in out tel_tty) is
begin
--
-- Abort is used here as this is only called when the program is
-- terminating and if no telnet connection has been made, the
-- task will be blocked waiting for a connection.
--
abort self.T;
-- self.T.end_task;
end;
--
-- Task type for telnet type server
--
task body telnet_server is
data : telnet_access;
host : BBS.Sim_CPU.sim_access;
exit_flag : Boolean := False;
sock_ser : GNAT.Sockets.Socket_Type; -- Server Socket
sock_com : GNAT.Sockets.Socket_Type; -- Communication Socket
rx_task : telnet_rx;
local : GNAT.Sockets.Sock_Addr_Type;
s : GNAT.Sockets.Stream_Access;
begin
accept start(self : telnet_access; port : GNAT.Sockets.Port_Type; owner : BBS.Sim_CPU.sim_access) do
data := self;
local.Addr := GNAT.Sockets.Any_Inet_Addr;
local.Port := port;
host := owner;
GNAT.Sockets.Create_Socket(sock_ser, GNAT.Sockets.Family_Inet,
GNAT.Sockets.Socket_Stream);
GNAT.Sockets.Set_Socket_Option(sock_ser, GNAT.Sockets.Socket_Level,
(GNAT.Sockets.Reuse_Address, True));
GNAT.Sockets.Bind_Socket(sock_ser, local);
GNAT.Sockets.Listen_Socket(sock_ser);
end start;
loop
select
accept write(char : Character) do
String'write(s, "" & char);
end write;
or
accept end_task do
exit_flag := True;
end end_task;
or
delay 0.0;
end select;
exit when exit_flag;
if data.all.disconnecting then
--
-- This produces a warning that sock_com may be used before
-- it's set. This should not be a problem in normal operation
-- since connected has to be set True before disconnecting
-- can be set false.
--
pragma Warnings (Off, "Connections happens before disconnecting");
GNAT.Sockets.Close_Socket(sock_com);
pragma Warnings (On, "Connections happens before disconnecting");
data.all.disconnecting := False;
end if;
if not data.all.connected then
--
-- This call blocks until a connection request comes in.
--
GNAT.Sockets.Accept_Socket(sock_ser, sock_com, local);
s := GNAT.Sockets.Stream(sock_com);
data.all.connected := True;
String'write(s, "Connected to simulated CPU " & host.name & CRLF);
rx_task.start(data, sock_com, host);
end if;
end loop;
rx_task.end_task;
GNAT.Sockets.Close_Socket(sock_ser);
GNAT.Sockets.Close_Socket(sock_com);
end telnet_server;
--
-- Task body for telnet receiver task. This is intended to only be
-- used by the main telnet task for reciving characters from the
-- network connection.
--
task body telnet_rx is
exit_flag : Boolean := False;
data : telnet_access;
host : BBS.Sim_CPU.sim_access;
sock_com : GNAT.Sockets.Socket_Type;
last : Ada.Streams.Stream_Element_Offset;
elem : Ada.Streams.Stream_Element_Array(1 .. 1);
cmd_state : byte := 0;
begin
accept start(self : telnet_access; sock : GNAT.Sockets.Socket_Type; owner : BBS.Sim_CPU.sim_access) do
data := self;
sock_com := sock;
host := owner;
end start;
loop
select
accept end_task do
exit_flag := True;
end end_task;
or
accept start(self : telnet_access; sock : GNAT.Sockets.Socket_Type; owner : BBS.Sim_CPU.sim_access) do
data := self;
sock_com := sock;
host := owner;
end start;
or
delay 0.0;
end select;
exit when exit_flag;
if data.all.connected then
GNAT.Sockets.Receive_Socket(sock_com, elem, last);
-- Ada.Text_IO.Put_Line("TTY: Character received: " & toHex(byte(elem(1))));
if last = 0 then
data.all.connected := False;
data.all.disconnecting := True;
-- Ada.Text_IO.Put_Line("TTY: Receiver disconnecting");
--
-- If the client has not read the last character, drop the current
-- current one. Buffering could be added at some point, but this
-- seems to be consistent with the way that CP/M works.
--
else
--
-- The telnet protocol uses in-band signalling with FF
-- indicating the start of option signalling. The sequences
-- I've seen are:
-- FF FD 01 (IAC DO echo?)
-- FF FD 03 (IAC DO supress go ahead?)
-- There are more defined somewhere. We just want to ignore
-- them for now. If a character FF needs to be sent, it is
-- sent as FF FF. It may be that at some point, software
-- running on the simulator may wish to see these. At that
-- point, it could be made into an option.
--
if (elem(1) = 16#FF#) and ((cmd_state = 0) or (cmd_state = 3)) then -- Start of CMD
cmd_state := 1;
elsif (elem(1) = 16#FF#) and (cmd_state = 1) then -- Escaped FF
cmd_state := 0;
elsif cmd_state = 1 then -- Ignore next character
cmd_state := 2;
elsif cmd_state = 2 then -- Ignore next character
cmd_state := 3;
elsif cmd_state = 3 then -- Reset
cmd_state := 0;
end if;
if (not data.all.ready) and (cmd_state = 0) then
-- Ada.Text_IO.Put_Line("TTY: Character stored: " & toHex(byte(elem(1))));
data.all.char := Character'Val(elem(1));
data.all.ready := True;
end if;
end if;
if data.all.int_e and data.all.ready then
-- Ada.Text_IO.Put_Line("TTY: Sending interrupt " & toHex(data.all.int_code));
host.interrupt(data.all.int_code);
end if;
end if;
end loop;
end telnet_rx;
end;
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