[syslinux] nilo -> tftp-hpa interaction

[Josef Siemes]

Hi,

Giulio Orsero <giulioo at pobox.com> schrieb am 04.02.02:
> On Mon, 4 Feb 2002 17:21:48 +0100, Josef Siemes <jsiemes at web.de> wrote:
> 
> >Giulio Orsero <giulioo at pobox.com> schrieb am 04.02.02:
> >> Floppy starts, detects nic, receives ip from dhcp server, requests boot
> >> image to tftpd-hpa, then crashes when talking to tftp. Is  "Unknown TFTP
> >> packet type 0x53ff" a kind of packet I can block using tftp-hpa -r option,
> >> or it it nilo that is broken and there's nothing to do?
> >
> >hmm, could you try to make some tcpdump of this? Maybe this sheds
> >some light on it.
> 18:02:06.370927 192.168.1.115.2001 > 192.168.1.7.69: 20 RRQ "niloboot"
>                          4500 0030 0000 0000 3c11 faf2 c0a8 0173
>                          c0a8 0107 07d1 0045 001c 0000 0001 6e69
>                          6c6f 626f 6f74 006e 6574 6173 6369 6900

This reads 'RRQ niloboot netascii'. netascii? Why would anyone
want to download binaries as netascii? This should have been 
'... octet'!

> 18:02:06.374918 192.168.1.7.3012 > 192.168.1.115.2001: udp 516
>                          4500 0220 0fb8 0000 4011 e54a c0a8 0107
>                          c0a8 0173 0bc4 07d1 020c f5af 0003 0001
>                          3613 031b 5400 0000 0000 2092 0000 8092
>                          6d6b 6e62 692d

'Data 0001 <data>'. 

So there's no option acknowledgement, since no option was requested.
Since the 'netascii' packets tend to be bigger than the 'octet'
packets I think this stumbles over some packet != 512 Bytes data, and
it seems to be the first one ...

Try to patch formats[] in tftpd.c, so that the last entry in each
element is '0'. This should give:

:} formats[] = {
:  {"netascii", [...] ,tftp_recvfile, 0 },
:  {"octet" , [...], 0},

This disables CR/LF conversion even if 'netascii' is requested.
Maybe this brings you some step further, but since this client 
is definitely broken there may be more trouble elsewhere.

Regards,

Josef
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