Re: inetutils-1.3.2 tftp file limit 16MB

[Alain Magloire]

> 
> GNU tftp and/or tftpd has a 16 Mega Byte limit on file transfers, as 
> demonstrated by a transfer with the following options
> 
> > tftp HOSTNAME
> > bin
> > verbose
> > trace
> > get BIGFILE
> [...]
> received DATA <block=32767, 512 bytes>
> sent ACK <block=32767>
> received DATA <block=-32768, 512 bytes>
> sent ACK <block=32767>
> received DATA <block=-32768, 512 bytes>
> received DATA <block=-32768, 512 bytes>
> sent ACK <block=32767>
> sent ACK <block=32767>
> sent ACK <block=32767>
> Transfer timed out.
> 
> tftp> 
> 
> I believe that changing the data type for tu_block to unsigned short would 
> raise the limit to 32M
> 
> [inetutils-1.3.2/include/arpa/tftp.h]
> struct        tftphdr {
>       short   th_opcode;              /* packet type */
>       union {
>               short   tu_block;       /* block # */
>               short   tu_code;        /* error code */
>               char    tu_stuff[1];    /* request packet stuff */
>       } th_u;
>       char    th_data[1];             /* data or error string */
> };
> 
> #define       th_block        th_u.tu_block
> #define       th_code         th_u.tu_code
> #define       th_stuff        th_u.tu_stuff
> #define       th_msg          th_data
> 
> , and changing variable 'block' in tftpd.c/tftp.c functions sendfile/recvfile 
> to unsigned short would result in unlimited file size, because both sides of 
> comparison would overflow into -32768 at the same time.


Unless I missed the obvious, changing this will make it impossible to work with 
other
since you are changing the struct size, tftp.h is an expose file and provided 
for
convenience if the platform does not have it in /usr/include/arpa/tftp.h