Re: [PATCH gwproxy v8 2/2] gwproxy: refactor code base to add experimental raw DNS backend

[Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>]

On Sat, Sep 6, 2025 at 8:30 PM Alviro Iskandar Setiawan wrote:
>         But note that, since the lifetime of the "struct
> gwp_conn_pair" is now tied to both:
>         1) The SOCKS5 session, and
>         2) The DNS resolution query.
> You will need to make "struct gwp_conn_pair" refcounted to avoid
> use-after-free in case the DNS resolution query completes after the
> SOCKS5 session has been killed.

Thinking about this more, I found that the "struct gwp_conn_pair" does
not need to be refcounted. So, we have:
        struct gwp_conn_pair *sess_map[65536];

Initially, set:
        sess_map[0..65535] = NULL;
then, when a SOCKS5 needs a DNS query, generate a txid, then set:
        sess_map[txid] = socks5 session;
if the socks5 session dies first before the DNS query completes, set:
        sess_map[txid] = NULL;
then, when the DNS query completes and it sees sess_map[txid] == NULL,
just drop the response, do nothing. No refcount needed.