passt/pesto.c, branch 2026_05_07.1afd4ed

pesto, conf, fwd_rule: Add options and modes to add, delete, clear rules

2026-05-07T06:06:30+00:00

Instead of just being able to add to the existing tables, implement
an explicit --clear option to replace them, which now becomes the
default behaviour, and implement explicit --add and --delete options
to maintain the table and add or delete specific ports.

The option --clear PIF forces the clearing of a table, instead.

These options can be combined arbitrarily and are handled as
sequential commands, as now described in pesto(1).

If no option is given before forwarding specifiers for a matching
table, the command line is interpreted as a replacement of the
existing rules.

To this end:

- there's no protocol change, as pesto is anyway sending updated
  copies of the table

- the forwarding table functions now include a new fwd_rule_del(),
  which deletes existing rule only if a matching one is found

- a trivial fwd_rule_clear() is factored out from the existing
  conf_handler() implementation, so that it can be directly used
  in pesto

The entry points for parsing of port specifiers now take an additional
'del' parameter which is passed down all the way before reaching the
fwd_rule_add() implementation. If a rule should be deleted, at that
point, fwd_rule_del() is called instead.

Signed-off-by: Stefano Brivio 
Reviewed-by: Laurent Vivier 
Reviewed-by: David Gibson

pesto, conf: Send updated rules from pesto back to passt/pasta

2026-05-07T06:06:30+00:00

Extend pesto to send the updated rule configuration back to passt/pasta.
Extend passt/pasta to read the new configuration and store the new rules in
a "pending" table.   We don't yet attempt to activate them.

Signed-off-by: Stefano Brivio 
[dwg: Based on an early draft from Stefano]
[sbrivio: Add redundant check on interface names being terminated in
 conf_recv_rules(), to make static checkers happy]
[sbrivio: Make conf_recv_rules() return -1 if fwd_rule_read() fails,
 as suggested by Jon Maloy]
[sbrivio: Fix conflicts in Makefile]
Signed-off-by: David Gibson 
Reviewed-by: Laurent Vivier

pesto: Parse and add new rules from command line

2026-05-07T06:06:30+00:00

This adds parsing of options using fwd_rule_parse(), validates them and
adds them to the existing rules. It doesn't yet send those rules back to
passt or pasta.

Message-ID: <20260322141843.4095972-3-sbrivio@redhat.com>
[dwg: Based on an early draft by Stefano]
Signed-off-by: David Gibson 
[sbrivio: Recycled usage messages for -T and -U from conf.c as
 suggested by Laurent, dropped unrelated whitespace change]
[sbrivio: Add description of -t, -u, -T, -U to pesto.1]
[sbrivio: Fix conflicts in Makefile]
[sbrivio: Add description of -s to pesto.1 as well]
Signed-off-by: Stefano Brivio 
Reviewed-by: Laurent Vivier

pesto: Read current ruleset from passt/pasta and optionally display it

2026-05-07T06:06:30+00:00

Implement serialisation of our current forwarding rules in conf.c,
deserialising it to display in the pesto client.  Doing this requires
adding ip.c, inany.c, bitmap.c, lineread.c and fwd_rule.c to the pesto
build.  With previous preparations that now requires only a trivial change
to lineread.c.

Signed-off-by: David Gibson 
Reviewed-by: Laurent Vivier 
[sbrivio: Use ntohs() for rule->to instead of htons() in
 fwd_rule_read(), reported by Jon Maloy]
[sbrivio: Add upper bound check on pc->fwd.count for count of rules
 received by pesto, reported missing by Laurent, plus nits also
 reported by Laurent]
[sbrivio: Fix conflicts in Makefile]
Signed-off-by: Stefano Brivio

pesto: Expose list of pifs to pesto and display them

2026-05-07T06:06:30+00:00

Extend the dynamic update protocol to expose the pif indices and names
from a running passt/pasta to the pesto tool.  pesto records that data
and prints it out.

Signed-off-by: David Gibson 
Reviewed-by: Laurent Vivier 
[sbrivio: In read_pif_conf(), force a redundant termination of the
 interface name, the existing check isn't obvious enough for static
 checkers]
[sbrivio: Drop @resv_ left-over in description of struct
 pesto_pif_info, reported by Jon Maloy]
[sbrivio: Fix minor nits reported by Laurent]
[sbrivio: Initialise struct pesto_pif_info in conf_send_rules() with
 zeroes, otherwise the pif name might be seen as not terminated, and
 we'll expose memory from the back-end]
[sbrivio: Fix conflicts in Makefile]
Signed-off-by: Stefano Brivio

pesto, conf: Have pesto connect to passt and check versions

2026-05-07T06:06:30+00:00

Start implementing pesto in earnest.  Create a control/configuration
socket in passt.  Have pesto connect to it and retrieve a server greeting
Perform some basic version checking.

Signed-off-by: David Gibson 
[sbrivio: Avoid potential recursive calling between conf_accept() and
 conf_close(), reported by clang-tidy]
[sbrivio: In conf(), check we're not exceeding sizeof(c->control_path)
 instead of sizeof(c->socket_path), and, in pesto's main(), print
 argv[optind] instead of argv[1] to indicate an invalid socket path,
 both reported by Jon Maloy]
[sbrivio: In pesto's main(), drop unnecessary newline from error
 message, reported by Laurent]
[sbrivio: Don't use SOCK_NONBLOCK on accept4(), as that only applies
 to the *new* file descriptor, which we don't want -- set O_NONBLOCK
 on the listening file descriptor using fcntl()]
[sbrivio: Switch to protocol version 1, and reflect the true magic
 behind pesto, i.e. basil, into the magic string]
[sbrivio: Fix conflicts in the Makefile caused by the fact that I'm
 not merging a previous series reworking it]
Signed-off-by: Stefano Brivio 
Reviewed-by: Laurent Vivier

pesto, log: Share log.h (but not log.c) with pesto tool

2026-05-07T06:06:30+00:00

In pesto we're going to want several levels of error/warning messages, much
like passt itself.  Particularly as we start to share mode code between
passt and pesto, we want to use a similar interface to emit those.  However
we don't want to use the same implementation - logging to a file or syslog
doesn't make sense for the command line tool.

To accomplish this loosely share log.h, but not log.c between pesto and
passt.  In fact, an #ifdef means even most of log.h isn't actually shared,
but we do provide similar warn(), die() etc. macros.

This includes the *_perror() variants, which need strerror().  However,
we want to avoid allocations for pesto as we do for passt, and strerror()
allocates in some libc versions.  Therefore, also move our workaround for
this to be shared with pesto.

Reviewed-by: Laurent Vivier 
[dwg: Based on changes part of a larger patch by Stefano]
Signed-off-by: David Gibson 
[sbrivio: Dropped debug_perror_() as it's not used anyway, Laurent was
 asking about its name]
[sbrivio: Fix conflicts in the Makefile caused by the fact that I'm
 not merging a previous series reworking it]
[sbrivio: For some reason, this triggers some unrelated, but valid,
 cppcheck warnings in tap.c and conf.c: fix / suppress them]
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

pesto: Introduce stub configuration tool

2026-05-07T06:06:30+00:00

Build a new "pesto" binary, which will become the tool to update a running
passt/pasta's configuration.  For now, we just build a stub binary which
sets up a basic environment, parses trivial command line options but does
nothing else.

Signed-off-by: David Gibson 
[sbrivio: Dropped leading _ from comment to include guard endif,
 reported by Laurent]
[sbrivio: Formatting changes in pesto.1: use 80 columns instead of
 wrapping at about 75. Add description for -d, -h, --version.]
[sbrivio: Drop note from man page about pesto being experimental,
 we're shipping it so that people can actually use it]
[sbrivio: Fix conflicts in the Makefile as I'm not applying the
 previous series reworking it]
Signed-off-by: Stefano Brivio 
Reviewed-by: Laurent Vivier