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=cjk5M+tn; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id B30395A0626 for ; Thu, 08 Jan 2026 03:29:52 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202512; t=1767839390; bh=1UuID5i4lxKoF8rVTtTqLhcB62+ODTpaaQyC5FAguDs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cjk5M+tnvm1OZNFmYQN2/H8piAqP/f7PcFUinMpLwWauLiiBHs0XKXcA2eaxQh9dD 70LSslO29c2ukYgapCC5xt5fFCNURjZQ0EnfFQdsPiHnvpWotwrXD6Ll6pSe76vORY 6iAFA8cp9jPU4eTR7Hhslhp1q7EkMItxAV1sxV2dsyCKaB+p08JP/vGm6dI+SurJLF JtuhRlQY0E3JLs7/giEAEcBw0F03vwKxPw1+ZpOzqxLy2cY3SVLiPMFR8qEvrcwReP ncEtOOzEWxk44fK5dq63q1MtLeY6lFsuKRfBawgw/PFEQ6dx9NgUao/352Py6wrS+m iLdF60ORmMdXw== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dmplL3Xtrz4wRD; Thu, 08 Jan 2026 13:29:50 +1100 (AEDT) From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH v3 04/14] conf, fwd: Record "auto" port forwards in forwarding table Date: Thu, 8 Jan 2026 13:29:38 +1100 Message-ID: <20260108022948.2657573-5-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260108022948.2657573-1-david@gibson.dropbear.id.au> References: <20260108022948.2657573-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: P7I6O2YFCPB7P4LUVCLORK5D2UY5N4TR X-Message-ID-Hash: P7I6O2YFCPB7P4LUVCLORK5D2UY5N4TR 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 | 18 +++++++++++------- fwd.h | 2 ++ 3 files changed, 39 insertions(+), 12 deletions(-) diff --git a/conf.c b/conf.c index b486fefe..0bcf80d7 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 */ @@ -2202,6 +2202,27 @@ 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 ad398e54..69aca441 100644 --- a/fwd.c +++ b/fwd.c @@ -344,7 +344,7 @@ 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; @@ -375,7 +375,8 @@ 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; } } @@ -391,19 +392,22 @@ 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 *weak = rule->flags & FWD_WEAK ? " WEAK" : ""; + const char *scan = rule->flags & FWD_SCAN ? " AUTO" : ""; const char *percent = *rule->ifname ? "%" : ""; char addr[INANY_ADDRSTRLEN]; inany_ntop(fwd_rule_addr(rule), addr, sizeof(addr)); 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 3dfc7959..94869c2a 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 we scan a listener on the target * * FIXME: @addr and @ifname currently ignored for outbound tables */ @@ -35,6 +36,7 @@ struct fwd_rule { in_port_t first, last, to; #define FWD_DUAL_STACK_ANY BIT(0) #define FWD_WEAK BIT(1) +#define FWD_SCAN BIT(2) uint8_t flags; }; -- 2.52.0