Re: [PATCH v2 16/23] conf: Move "all" handling to port specifier

[Stefano Brivio <sbrivio@redhat.com>]

On Fri, 10 Apr 2026 11:03:02 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> Currently -[tTuU] all is handled separately in conf_ports() before calling
> conf_ports_spec().  Earlier changes mean we can now move this handling to
> conf_ports_spec().  This makes the code slightly simpler, but more
> importantly it allows some useful combinations we couldn't previously do,
> such as
> 	-t 127.0.0.1/all
> or
> 	-u %eth2/all
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  conf.c  | 25 ++++++++++---------------
>  passt.1 | 28 ++++++++++++++++++++--------
>  2 files changed, 30 insertions(+), 23 deletions(-)
> 
> diff --git a/conf.c b/conf.c
> index 5d6517c3..f62109b5 100644
> --- a/conf.c
> +++ b/conf.c
> @@ -251,6 +251,11 @@ static void conf_ports_spec(const struct ctx *c,
>  	const char *p, *ep;
>  	unsigned i;
>  
> +	if (!strcmp(spec, "all")) {
> +		/* Treat "all" as equivalent to "": all non-ephemeral ports */
> +		spec = "";
> +	}
> +
>  	/* Mark all exclusions first, they might be given after base ranges */
>  	for_each_chunk(p, ep, spec, ",") {
>  		struct port_range xrange;
> @@ -372,19 +377,6 @@ static void conf_ports(const struct ctx *c, char optname, const char *optarg,
>  		return;
>  	}
>  
> -	if (!strcmp(optarg, "all")) {
> -		uint8_t exclude[PORT_BITMAP_SIZE] = { 0 };
> -
> -		/* Exclude ephemeral ports */
> -		fwd_port_map_ephemeral(exclude);
> -
> -		conf_ports_range_except(c, optname, optarg, fwd,
> -					proto, NULL, NULL,
> -					1, NUM_PORTS - 1, exclude,
> -					1, FWD_WEAK);
> -		return;
> -	}
> -
>  	strncpy(buf, optarg, sizeof(buf) - 1);
>  
>  	if ((spec = strchr(buf, '/'))) {
> @@ -1039,14 +1031,17 @@ static void usage(const char *name, FILE *f, int status)
>  		"    can be specified multiple times\n"
>  		"    SPEC can be:\n"
>  		"      'none': don't forward any ports\n"
> -		"      'all': forward all unbound, non-ephemeral ports\n"
>  		"%s"
>  		"      [ADDR[%%IFACE]/]PORTS: forward specific ports\n"
> -		"        PORTS is a comma-separated list of ports, optionally\n"
> +		"        PORTS is either 'all' (forward all unbound, non-ephemeral\n"
> +		"        ports), or a comma-separated list of ports, optionally\n"
>  		"        ranged with '-' and optional target ports after ':'.\n"
>  		"        Ranges can be reduced by excluding ports or ranges\n"
>  		"        prefixed by '~'\n"
>  		"        Examples:\n"
> +		"        -t all         Forward all ports\n"

Nit: the examples below have a tab as a separator, which makes it
slightly easier to ensure we indent them properly.

> +		"        -t 127.0.0.1/all Forward all ports from local address\n"
> +		"                         127.0.0.1\n"

This makes things pretty hard on eyes as it's not consistent with the
rest of the "table". Could we perhaps do:

		"        -t ::1/all	Forward all ports from ::1\n"

?

>  		"        -t 22		Forward local port 22 to 22 on %s\n"
>  		"        -t 22:23	Forward local port 22 to 23 on %s\n"
>  		"        -t 22,25	Forward ports 22, 25 to ports 22, 25\n"
> diff --git a/passt.1 b/passt.1
> index d329f8f0..3ba447d5 100644
> --- a/passt.1
> +++ b/passt.1
> @@ -434,12 +434,6 @@ Configure TCP port forwarding to guest or namespace. \fIspec\fR can be one of:
>  .BR none
>  Don't forward any ports
>  
> -.TP
> -.BR all
> -Forward all unbound, non-ephemeral ports, as permitted by current capabilities.
> -For low (< 1024) ports, see \fBNOTES\fR. No failures are reported for
> -unavailable ports, unless no ports could be forwarded at all.
> -
>  .TP
>  .BR auto " " (\fBpasta\fR " " only)
>  Dynamically forward ports bound in the namespace. The list of ports is
> @@ -449,10 +443,20 @@ periodically derived (every second) from listening sockets reported by
>  .TP
>  [\fIaddress\fR[\fB%\fR\fIinterface\fR]\fB/\fR]\fIports\fR ...
>  Specific ports to forward.  Optionally, a specific listening address
> -and interface name (since Linux 5.7) can be specified.  \fIports\fR is
> -a comma-separated list of entries which may be any of:
> +and interface name (since Linux 5.7) can be specified.  \fIports\fR
> +may be either:
>  .RS
>  .TP
> +\fBall\fR
> +Forward all unbound, non-ephemeral ports, as permitted by current
> +capabilities.  For low (< 1024) ports, see \fBNOTES\fR. No failures
> +are reported for unavailable ports, unless no ports could be forwarded
> +at all.
> +.RE
> +
> +.RS
> +or a comma-separated list of entries which may be any of:
> +.TP
>  \fIfirst\fR[\fB-\fR\fIlast\fR][\fB:\fR\fItofirst\fR[\fB-\fR\fItolast\fR]]
>  Include range. Forward port numbers between \fIfirst\fR and \fIlast\fR
>  (inclusive) to ports between \fItofirst\fR and \fItolast\fR.  If
> @@ -473,6 +477,14 @@ unavailable ports, unless no ports could be forwarded at all.
>  Examples:
>  .RS
>  .TP
> +-t all
> +Forward all unbound, non-ephemeral ports as permitted by current
> +capabilities to the corresponding port on the guest or namespace
> +.TP
> +-t 127.0.0.1/all
> +For the local address 127.0.0.1, forward all unbound, non-ephemeral
> +ports as permitted by current capabilities.

Nit: all the other examples have no dot at the end (I tend to think
it fits better this type of list, but all I care about is that it's
consistent).

> +.TP
>  -t 22
>  Forward local port 22 to port 22 on the guest or namespace
>  .TP

-- 
Stefano