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=mSJXUUYV; dkim-atps=neutral Received: from mail.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) by passt.top (Postfix) with ESMTPS id BE5D75A0776 for ; Fri, 19 Dec 2025 15:19:16 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202512; t=1766153948; bh=0H7CACgyE35B2ytGiiRaO6mo3Q4ALHzRtooIQIZQB+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mSJXUUYVY2+kdhZXfPl3B0TKQr6MWjYvCHngFaFwkb+fXNNMeOywV3BuE60DS4GZ1 IMwumgYN1Y/6TAQL3Z41GNjLYxq8rxpUn7+wWjpgeOK65UpOYGdet8jNBeRz6w/6PA 1OWPze4xVjFe9OHyTdwLuxREzXjUd30yqmUP4QVwM2I4ZDRU6ejNiPsmHRYoqmmpD7 p6SuqUbEPpf/pvZ3eJFmfy160KzJ9wTpbntnA65UiyPz/MU1p8hNo8jD5pO5ARy6lJ rh6FbKv3WRAWXVHJ9vpCAJWK7P8x5PpuCBS1iT1FBoSQFutHiEBv34h2AKkUYLKPvr AMG1cEv/ZwMEQ== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dXqR031FTz4wMS; Sat, 20 Dec 2025 01:19:08 +1100 (AEDT) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH v2 07/12] fwd: Make space to store listening sockets in forward table Date: Sat, 20 Dec 2025 01:18:59 +1100 Message-ID: <20251219141904.1758072-8-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251219141904.1758072-1-david@gibson.dropbear.id.au> References: <20251219141904.1758072-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: URMPLDS75KZGJXL32QOWZ4HDEQ64WBMM X-Message-ID-Hash: URMPLDS75KZGJXL32QOWZ4HDEQ64WBMM 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: At present, we don't keep track of the fds for listening sockets (except for "auto" ones). Since the fd is stored in the epoll reference, we didn't need an alternative source of it for the various handlers. However, we're intending to allow dynamic changes to forwarding configuration in future. That means we need a way to enumerate sockets so we can close them on removal of a forward. Extend our forwarding table data structure to make space for all the listening sockets. To avoid allocation, this imposes another limit: we could run out of space for socket fds before we run out of forwarding entries. We don't actually do anything with the allocate space yet. Plus, for "auto" forwards the new space is redundant with existing arrays. We'll fix both of those in later patches. Signed-off-by: David Gibson --- fwd.c | 8 ++++++++ fwd.h | 11 +++++++++++ 2 files changed, 19 insertions(+) diff --git a/fwd.c b/fwd.c index 5e5dc58c..5215cee9 100644 --- a/fwd.c +++ b/fwd.c @@ -332,12 +332,15 @@ void fwd_table_add(struct fwd_ports *fwd, uint8_t flags, { /* Flags which can be set from the caller */ const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN; + unsigned num = (unsigned)last - first + 1, i; struct fwd_entry *new; ASSERT(!(flags & ~allowed_flags)); if (fwd->count >= ARRAY_SIZE(fwd->tab)) die("Too many port forwarding ranges"); + if ((fwd->listen_sock_count + num) > ARRAY_SIZE(fwd->listen_socks)) + die("Too many listening sockets"); new = &fwd->tab[fwd->count++]; new->flags = flags; @@ -358,6 +361,11 @@ void fwd_table_add(struct fwd_ports *fwd, uint8_t flags, new->last = last; new->to = to; + + new->socks = &fwd->listen_socks[fwd->listen_sock_count]; + fwd->listen_sock_count += num; + for (i = 0; i < num; i++) + new->socks[i] = -1; } /** diff --git a/fwd.h b/fwd.h index eef507c6..84c463e2 100644 --- a/fwd.h +++ b/fwd.h @@ -23,6 +23,7 @@ bool fwd_port_is_ephemeral(in_port_t port); * @first: First port number to forward * @last: Last port number to forward * @to: Port number to forward port @first to. + * @socks: Array of listening sockets for this entry * @flags: Flag mask * FWD_DUAL_STACK - forward both IPv4 and IPv6 (requires @addr be ::) * FWD_WEAK - Don't give an error if binds fail for some forwards @@ -34,6 +35,7 @@ struct fwd_entry { union inany_addr addr; char ifname[IFNAMSIZ]; in_port_t first, last, to; + int *socks; #define FWD_DUAL_STACK BIT(0) #define FWD_WEAK BIT(1) #define FWD_SCAN BIT(2) @@ -52,6 +54,13 @@ enum fwd_ports_mode { #define PORT_BITMAP_SIZE DIV_ROUND_UP(NUM_PORTS, 8) +/* Maximum number of listening sockets (per pif & protocol) + * + * Rationale: This lets us listen on every port for two addresses (which we need + * for -T auto without SO_BINDTODEVICE), plus a comfortable number of extras. + */ +#define MAX_LISTEN_SOCKS (NUM_PORTS * 3) + /** * fwd_ports() - Describes port forwarding for one protocol and direction * @mode: Overall forwarding mode (all, none, auto, specific ports) @@ -68,6 +77,8 @@ struct fwd_ports { struct fwd_entry tab[MAX_FWDS]; uint8_t map[PORT_BITMAP_SIZE]; in_port_t delta[NUM_PORTS]; + unsigned listen_sock_count; + int listen_socks[MAX_LISTEN_SOCKS]; }; #define FWD_PORT_SCAN_INTERVAL 1000 /* ms */ -- 2.52.0