Re: [PATCH 02/18] conf: Simplify handling of default forwarding mode

On Tue, 7 Apr 2026 13:16:14 +1000 David Gibson wrote:

For passt, the default forwarding mode is "none", which falls out naturally from the other handling: if we don't get any options, we get empty forwarding tables, which corresponds to "none" behaviour. However, for pasta the default is "auto". This is handled a bit oddly: in conf_ports() we set the mode variable, but don't set up the rules we need for "auto" mode. Instead we want until nearly the end of conf() and if the mode is FWD_MODE_AUTO or unset, we make conf_ports_range_except() calls to set up the "auto" rules.

Simplify this a bit, by creating the rules within conf_ports() itself when we parse -[tuTU] auto. For the case of no forwarding options we call into conf_ports() itself with synthetic arguments. As well as making the code a little shorter, this makes it more obvious that giving no arguments really is equivalent to -[tuTU] auto.

Signed-off-by: David Gibson --- conf.c | 54 ++++++++++++++++++++++-------------------------------- 1 file changed, 22 insertions(+), 32 deletions(-)

diff --git a/conf.c b/conf.c index c515480b..7d718f91 100644 --- a/conf.c +++ b/conf.c @@ -345,6 +345,10 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg, die("'auto' port forwarding is only allowed for pasta");

*mode = FWD_MODE_AUTO; + + conf_ports_range_except(c, optname, optarg, fwd, NULL, NULL, + 1, NUM_PORTS - 1, NULL, 1, FWD_SCAN); + return; }

Pre-existing, it goes away in 12/18 of the current series, and it's harmless unless somebody should ever touch 'enum fwd_mode' in a rather unlikely way: the code here checks: if (*mode) ... relying on the fact that FWD_MODE_UNSPEC is 0 (and we also have a _NONE value, which makes it somewhat risky) instead of directly checking if (*mode == FWD_MODE_UNSPEC). I thought I would note it here in the unlikely case we'd need to back to mode constants for whatever reason. -- Stefano