Re: [dpdk-dev] [PATCH v5 1/4] examples/multi_process/client_server_mp: check port validity

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 6 Aug 2019 08:19:01 +0000
Matan Azrad <matan@mellanox.com> wrote:

> From: Stephen Hemminger
> > On Sun, 4 Aug 2019 08:31:54 +0000
> > Matan Azrad <matan@mellanox.com> wrote:
> >   
> > > > > >  	/* convert parameter to a number and verify */
> > > > > >  	pm = strtoul(portmask, &end, 16);
> > > > > > -	if (end == NULL || *end != '\0' || pm == 0)
> > > > > > +	if (end == NULL || *end != '\0' || pm > UINT16_MAX || pm  
> > == 0)  
> > > > >
> > > > > Why pm > UINT16_MAX ? should be something like > (1 <<  
> > > > RTE_MAX_ETHPORTS) - 1.  
> > > > > And need to be sure pm type can hold RTE_MAX_ETHPORTS bits,  
> > > > otherwise port 0 may unlikely be all the time visible in the loop below.  
> > > > >  
> > > >
> > > > The DPDK assumes a lot of places that unsigned long will hold a port  
> > mask.  
> > >
> > > So, all are bugs, no?  
> > 
> > I don't think 32 bit build is that well tested. But yes a mask needs to hold 64
> > ports.  
> 
> What if someone changes RTE_MAX_ETHPORTS to be bigger than 64 in config file?
> 
> Assume the user changes RTE_MAX_ETHPORTS to 128, and there is a valid port in range [64, 127].
> Then,  assume the failsafe sub device owns port ID 0.
> 
> Because the mask bits are not enough to handle the above range, you will get port 0 as valid port - bug.
> 
> I think you need one more check to the RTE_MAX_ETHPORTS > 64 case. 

Not really needed.

The DPDK has lots of hard coded assumptions of all ports fitting in 64 bits.
Examples include testpmd/parameters.c etc.

The original concept of a small set of assigned values for portid is not going
to scale. It really should have been more like ifindex; something that is not
used by common API's much larger range; and assigned purely sequentially.

The API's should all be using names, but the DPDK port naming is also a mess...