Re: [net-next PATCH v5 0/3] net: reserve ports for applications using fixed port numbers

[Bill Fink <billfink@mindspring.com>]

On Sat, 20 Feb 2010, Octavian Purdila wrote:

> On Saturday 20 February 2010 10:11:40 you wrote:
> > Octavian Purdila wrote:
> > > This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports which
> > > allows users to reserve ports for third-party applications.
> > >
> > > The reserved ports will not be used by automatic port assignments
> > > (e.g. when calling connect() or bind() with port number 0). Explicit
> > > port allocation behavior is unchanged.
> > >
> > > Changes from the previous version:
> > > - switch the /proc entry format to coma separated list of range ports
> > > - treat -EFAULT just like any other error and acknowledge written values
> > > - use isdigit() in proc_get_ulong
> > >
> > > Octavian Purdila (3):
> > >   sysctl: refactor integer handling proc code
> > >   sysctl: add proc_do_large_bitmap
> > >   net: reserve ports for applications using fixed port numbers
> > 
> > Hi,
> > 
> > This version looks fine for me, but I need to give them a test, and
> > I will put feedbacks asap. Thanks for your work!
> > 
> > Still two things:
> > 
> > 1) bitops are always atomic on every arch, right? If yes, then ok.
> 
> AFAIK, yes.
> 
> > 2) I hope you could add some documentation to show the relations
> >     between ip_local_port_range and ip_local_reserved_ports.
> > 
> 
> How does this sound:
> 
> ip_local_reserved_ports - list of comma separated ranges
>         Specify the ports which are reserved for known third-party
>         applications. These ports will not be used by automatic port
>         assignments (e.g. when calling connect() or bind() with port
>         number 0). Explicit port allocation behavior is unchanged.
> 
>         The format used for both input and output is a comma separated
>         list of ranges (e.g. "1,2-4,10-10" for ports 1, 2, 3, 4 and
>         10). Writing to the file will clear all previously reserved
>         ports and update the current list with the one given in the
>         input.
> 
>         Note that ip_local_port_range and ip_local_port_range settings

Change second ip_local_port_range to ip_local_reserved_ports.

						-Bill



>         are independent and both are considered by the kernel when
>         determining which ports are available for automatic port
>         assignments.
> 
>         You can reserve ports which are not in the current
>         ip_local_port_range, e.g.:
> 
>         $ cat /proc/sys/net/ipv4/ip_local_port_range
>         32000   61000
>         $ cat /proc/sys/net/ipv4/ip_local_reserved_ports
>         8080,9148
> 
>         although this is redundant. However such a setting is useful
>         if later the port range is changed to a value that will
>         include the reserved ports.