zlib in PPP code

[Neustradamus]

There is zlib in /common:

• https://github.com/ppp-project/ppp/tree/master/common

There is zlib in /pppdump:

• https://github.com/ppp-project/ppp/tree/master/pppdump

It is needed to update or to delete from the code?

[paulusmack]

I added some functions to zlib in order to be able to support "deflate" packet compression more efficiently. If you try to use a standard zlib it won't work properly. If it was possible to use the standard zlib I would have done that from the beginning.

[Neustradamus]

@paulusmack: It has not been integrated since this very old version?

If not, maybe good to add a PR here:

• https://github.com/madler/zlib

[paulusmack]

The zlib in common is only used for the Solaris kernel modules. I'll ask @carlsonj if it is still needed.

There is also a zlib in the pppdump directory which is even older.

I don't want getting stuff merged into upstream zlib to be on the critical path for getting a release out.

[carlsonj]

On 10/27/22 01:42, Paul Mackerras wrote:

The zlib in common is only used for the Solaris kernel modules. I'll ask @carlsonj https://github.com/carlsonj if it is still needed.

There is also a zlib in the pppdump directory which is even older.

I don't want getting stuff merged into upstream zlib to be on the critical path for getting a release out.

It's needed if the BSD compress algorithm is used on a custom-compiled version of PPP on Solaris. I don't know of any other source for that in the Solaris kernel, so removing it would likely disable that feature. But, on the other hand, I don't know of any serious use of that data compression feature, so probably not a particularly high priority. Not really wedded to it.

-- James Carlson 42.703N 71.076W FN42lq08 @.***>

[paulusmack]

I don't mind leaving common/zlib.c there if there is a chance it is still useful to somebody. However, unless someone finds a vulnerability in it, I don't feel like putting in effort to update it either.

@Neustradamus note that this code is required in source form here since it is needed for compiling a kernel module. We can't use a system library for this.