slipd bugs

[fachat]

• slipd libip routines seem to be buggy still - very weird effects!
  I have no idea where they come from. When I start hunting one, it
  disappears and another pops up. Amongs them were:

  • closing telnet seems to set nthreads in kernel tables to $ff!!!!
  • also opening a telnet connection prints some weird characters on the
    wrong screen (stream gets "$ff $ff $c6 $07 $07 $07..." bytes sent,
    I have no idea where from...)
  • telnet works on telnet port somehow - bug hangs if streams are closed...
    should comply to rfc1143
  • httpd doesn't work although using almost all the same routines as
    rsh which work
  • SC_ESTAT does not seem to recognize E_EOF the same way as SC_STAT?
    (slipd, in rsh.a65, label newpkt)
    I have found and fixed a bug in the lib6502 fread/fwrite that could
    probably have caused this bug, but have not (yet) checked this.

• using inet apps without registering an inet task blocks those programs
  (kernel problem as not-registered task is not recognized)

• listen does not check if port already in use
  also there is no way to free listenports in use by crashed/killed
  programs - probably when reuse, overwrite old listenport such
  that table does not fill up?

• telnet doesn't really implement local echo mode.

• slipd uses accesses to $dc** (C64 CIA timers) to generate initial
  pseudo-random sequence numbers.

• when getting tcp signal, set error flag in associated streams

• SLIPD: wwwroot path given to chdir, but not used when opening a file;
  only the first letter is used as drive.

[fachat]

When running slipd with

ontty a:video2 slipd a:ser1

on the c64, sometimes it hangs in an infinite loop like this:

(C:$9fa1) n
.C:9fa3  24 0E       BIT $0E        - A:18 X:9F Y:03 SP:f6 .V-B.I.C  585709490
(C:$9fa3) 
.C:9fa5  10 FA       BPL $9FA1      - A:18 X:9F Y:03 SP:f6 .V-B.I.C  585709493
(C:$9fa5) 
.C:9fa1  A9 18       LDA #$18       - A:18 X:9F Y:03 SP:f6 .V-B.I.C  585709496
(C:$9fa1) 
.C:9fa3  24 0E       BIT $0E        - A:18 X:9F Y:03 SP:f6 .V-B.I.C  585709498

Where $9fa1 is "nmi_off" (in block 51).