From: Laurent Cimon <laurent@nilio.ca>
Subject: Re: relayd patch: allow http relays to have fallback tables
To: tech@openbsd.org
Date: Tue, 21 Jan 2025 10:09:12 -0500

HAS THIS EVER HAPPENED TO YOU?

"I think I'll add a fallback table for when the host is down"
table <site> { 127.0.0.1 }
table <fallback> { 127.0.0.1 }

log state changes
log connection

http protocol "proto" {
         match header log "Host"
         match url log

         pass request header "Host" value "localhost" forward to <site>
         pass request header "Host" value "localhost" forward to <fallback>
}

relay "proxy" {
         listen on lo port 80
         protocol "proto"
         forward to <fallback> port 8086
         forward to <site> port 4243 check tcp
}

  _____________________________
< WHY DOESN'T THIS FALLBACK?? >
  -----------------------------
    \         ,        ,
     \       /(        )`
      \      \ \___   / |
             /- _  `-/  '
            (/\/ \ \   /\
            / /   | `    \
            O O   ) /    |
            `-^--'`<     '
           (_.)  _  )   /
            `.___/`    /
              `-----' /
<----.     __ / __   \
<----|====O)))==) \) /====
<----'    `--' `.__,' \
              |        |
               \       /
         ______( (_  / \______
       ,'  ,-----'   |        \
       `--{__________)        \/

We can help! With this FREE patch, you can easily use fallback tables
with filtered HTTP relays and they will work just like with other relays
and redirects! Just as the manpage specifies!

Don't let manpage incoherence get to you!

Call 1-800-PATCHME that is 1-800-PATCHME

Call NOW! (don't call this number)

On 1/1/25 21:19, Laurent Cimon wrote:
> Hi,
>
> Currently, relayd does not use fallback tables in an http relay
> when there are matching filter rules. This is because it sets the
> table before relay_from_table is called.
>
> This small patch skips the goto when the table is down, allowing it
> to search through the table list.
>
> Wishing you all a good year,
> Laurent
>
> diff --git usr.sbin/relayd/relay.c usr.sbin/relayd/relay.c
> index 6d0970802c5..c7837acd4e0 100644
> --- usr.sbin/relayd/relay.c
> +++ usr.sbin/relayd/relay.c
> @@ -1289,9 +1289,12 @@ relay_from_table(struct rsession *con)
>          if (con->se_table != NULL) {
>                  rlt = con->se_table;
>                  table = rlt->rlt_table;
> +
> +               /* if the table is not up, continue searching */
>                  if (table->conf.check && !table->up)
>                          table = NULL;
> -               goto gottable;
> +               else
> +                       goto gottable;
>          }
>
>          /* otherwise grep the first active table */
>