Re: [PATCH net-next 0/2] net: core: Two Helper function about socket information

On Fri, Feb 3, 2017 at 9:13 AM, Alexei Starovoitov
[off-list ref] wrote:

I think sk_uid is self explanatory, but cookie is less so.
Please explain how you plan to use it.

The cookie is the only way to uniquely identify a given socket on the
system (the 5-tuple is not sufficient in the presence of SO_REUSEPORT,
for example). One goal for this infrastructure is to perform
per-socket accounting (ultimately replace the out-of-tree xt_qtaguid
code that is used for per-UID, per-socket-tag accounting on Android).
The socket cookie would be a natural key to use in a BPF map where the
values are socket accounting information.