From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202512 header.b=YJfpQHCr; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 35FF25A0623 for ; Thu, 15 Jan 2026 09:50:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202512; t=1768467049; bh=BTJ5r/r1lA8uBgQdjMxtiAr6Uzu62ksQAZ+p2jMD8os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YJfpQHCr2qmfh6qR5s/saqW23Ets3urec8eH5r0ibq73cvK9GeKKp0OzG4NoH0Ga3 M8XDuYj9cCCrxJXwtss8W5luUP9bPU5E+BjD7tpX1WyHNmmDaERMOALR1CA2x41ZYb eVs5ZeiNbzkA9BzMFPm+Pz9HYda//a/AOazZAC7tOcnYbakYD6dv9S4KAyWOqcr65B EVZ4AvWLHLGUdZRTZtZsentFgkQ+VWGFnGOMmRd6BdVp5IlIA+H4/MPRR/b9Y5TXML 1ZqIIz3l6JCOSC/D84t225dmGmxxzfuT/GNcBxX6VKVo3J45qquIJEySR2SR7i0VHn MvVuJu4ZZ/IgA== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dsGsj3GdDz4wMG; Thu, 15 Jan 2026 19:50:49 +1100 (AEDT) From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH v4 04/14] conf, fwd: Record "auto" port forwards in forwarding table Date: Thu, 15 Jan 2026 19:50:35 +1100 Message-ID: <20260115085045.3309818-5-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260115085045.3309818-1-david@gibson.dropbear.id.au> References: <20260115085045.3309818-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: A77ZKEUOMU34ADJV46PBBMCRORY5W2RN X-Message-ID-Hash: A77ZKEUOMU34ADJV46PBBMCRORY5W2RN X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Currently the forwarding table records details of explicit port forwards, but nothing for -[tTuU] auto. That looks a little odd on the debug output, and will be a problem for future changes. Extend the forward table to have rules for auto-scanned forwards, using a new FWD_SCAN flag. For now the mechanism of auto port forwarding isn't updated, and we will only create a single FWD_SCAN rule per protocol and direction. We'll better integrate auto scanning with other forward table mechanics in future. Signed-off-by: David Gibson --- conf.c | 31 ++++++++++++++++++++++++++----- fwd.c | 21 +++++++++++++-------- fwd.h | 2 ++ 3 files changed, 41 insertions(+), 13 deletions(-) diff --git a/conf.c b/conf.c index 475dbe04..fb6a8118 100644 --- a/conf.c +++ b/conf.c @@ -135,7 +135,7 @@ static int parse_port_range(const char *s, char **endptr, * @ifname: Listening interface * @first: First port to forward * @last: Last port to forward - * @exclude: Bitmap of ports to exclude + * @exclude: Bitmap of ports to exclude (may be NULL) * @to: Port to translate @first to when forwarding * @flags: Flags for forwarding entries */ @@ -168,11 +168,11 @@ static void conf_ports_range_except(const struct ctx *c, char optname, } for (base = first; base <= last; base++) { - if (bitmap_isset(exclude, base)) + if (exclude && bitmap_isset(exclude, base)) continue; for (i = base; i <= last; i++) { - if (bitmap_isset(exclude, i)) + if (exclude && bitmap_isset(exclude, i)) break; if (bitmap_isset(fwd->map, i)) { @@ -180,9 +180,9 @@ static void conf_ports_range_except(const struct ctx *c, char optname, "Altering mapping of already mapped port number: %s", optarg); } - if (optname == 't') + if (!(flags & FWD_SCAN) && optname == 't') fd = tcp_listen(c, PIF_HOST, addr, ifname, i); - else if (optname == 'u') + else if (!(flags & FWD_SCAN) && optname == 'u') fd = udp_listen(c, PIF_HOST, addr, ifname, i); else /* No way to check in advance for -T and -U */ @@ -2200,6 +2200,27 @@ void conf(struct ctx *c, int argc, char **argv) if (!c->udp.fwd_out.mode) c->udp.fwd_out.mode = fwd_default; + if (c->tcp.fwd_in.mode == FWD_AUTO) { + conf_ports_range_except(c, 't', "auto", &c->tcp.fwd_in, + NULL, NULL, 1, NUM_PORTS - 1, + NULL, 1, FWD_SCAN); + } + if (c->tcp.fwd_out.mode == FWD_AUTO) { + conf_ports_range_except(c, 'T', "auto", &c->tcp.fwd_out, + NULL, "lo", 1, NUM_PORTS - 1, + NULL, 1, FWD_SCAN); + } + if (c->udp.fwd_in.mode == FWD_AUTO) { + conf_ports_range_except(c, 'u', "auto", &c->udp.fwd_in, + NULL, NULL, 1, NUM_PORTS - 1, + NULL, 1, FWD_SCAN); + } + if (c->udp.fwd_out.mode == FWD_AUTO) { + conf_ports_range_except(c, 'U', "auto", &c->udp.fwd_out, + NULL, "lo", 1, NUM_PORTS - 1, + NULL, 1, FWD_SCAN); + } + if (!c->quiet) conf_print(c); } diff --git a/fwd.c b/fwd.c index e80312fb..588bf24a 100644 --- a/fwd.c +++ b/fwd.c @@ -345,7 +345,7 @@ void fwd_rule_add(struct fwd_ports *fwd, uint8_t flags, in_port_t first, in_port_t last, in_port_t to) { /* Flags which can be set from the caller */ - const uint8_t allowed_flags = FWD_WEAK; + const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN; struct fwd_rule *new; unsigned port; @@ -379,7 +379,8 @@ void fwd_rule_add(struct fwd_ports *fwd, uint8_t flags, for (port = new->first; port <= new->last; port++) { /* Fill in the legacy data structures to match the table */ - bitmap_set(fwd->map, port); + if (!(new->flags & FWD_SCAN)) + bitmap_set(fwd->map, port); fwd->delta[port] = new->to - new->first; } } @@ -395,21 +396,25 @@ void fwd_rules_print(const struct fwd_ports *fwd) for (i = 0; i < fwd->count; i++) { const struct fwd_rule *rule = &fwd->rules[i]; const char *percent = *rule->ifname ? "%" : ""; + const char *weak = "", *scan = ""; char addr[INANY_ADDRSTRLEN]; - const char *weak = ""; inany_ntop(fwd_rule_addr(rule), addr, sizeof(addr)); if (rule->flags & FWD_WEAK) weak = " (best effort)"; + if (rule->flags & FWD_SCAN) + scan = " (auto-scan)"; if (rule->first == rule->last) { - info(" [%s]%s%s:%hu => %hu %s", + info(" [%s]%s%s:%hu => %hu %s%s", addr, percent, rule->ifname, - rule->first, rule->to, weak); + rule->first, rule->to, weak, scan); } else { - info(" [%s]%s%s:%hu-%hu => %hu-%hu %s", - addr, percent, rule->ifname, rule->first, rule->last, - rule->to, rule->last - rule->first + rule->to, weak); + info(" [%s]%s%s:%hu-%hu => %hu-%hu %s%s", + addr, percent, rule->ifname, + rule->first, rule->last, + rule->to, rule->last - rule->first + rule->to, + weak, scan); } } } diff --git a/fwd.h b/fwd.h index d2a59c15..cc7e0aca 100644 --- a/fwd.h +++ b/fwd.h @@ -26,6 +26,7 @@ bool fwd_port_is_ephemeral(in_port_t port); * @flags: Flag mask * FWD_DUAL_STACK_ANY - match any IPv4 or IPv6 address (@addr should be ::) * FWD_WEAK - Don't give an error if binds fail for some forwards + * FWD_SCAN - Only forward if the matching port in the target is listening * * FIXME: @addr and @ifname currently ignored for outbound tables */ @@ -37,6 +38,7 @@ struct fwd_rule { in_port_t to; #define FWD_DUAL_STACK_ANY BIT(0) #define FWD_WEAK BIT(1) +#define FWD_SCAN BIT(2) uint8_t flags; }; -- 2.52.0