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=202408 header.b=nyonevtv; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 1F7D85A004F for ; Tue, 27 Aug 2024 08:04:52 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202408; t=1724738688; bh=rUwDEuceom5y1kWh6V3jTSeu0n369PQ607BEvJKCfeo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nyonevtvrWJdt0G5wzXbtXTcwKMRwxhJ+NA1mt1zUwD96ssxZiSuBDSM6gSSzwbKH y8gYFr2aDMVvvU5DzQlkejXHnI7TX9HJKFGwKNQpIym3eUeRFCVru8V1E3tkwDfP+h kCuvUBo5yLEjWThTC9gJPvm+akH5fq4mr6uPbk5y1vDehe1GYuSbN/ZvD9Rn+3w1jI CtW805oLDhJSOL70E2HIa/YlBa7hWZxRntX0YJrQ/pYWD5bKZ3HGgLf4XiRDLYHcZG 1TMKcYCB3xuQFWfTU3/d+OdqQw2RIm+KBZSFlPeKhPT+MSzCr0LVmSNB/nR6ip/STg 9m5SNTCss0xXA== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4WtH7h0ysHz4x8X; Tue, 27 Aug 2024 16:04:48 +1000 (AEST) From: David Gibson To: passt-dev@passt.top, Stefano Brivio Subject: [PATCH v2 3/3] udp: Use dual stack sockets for port forwarding when possible Date: Tue, 27 Aug 2024 16:04:46 +1000 Message-ID: <20240827060446.2601102-4-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240827060446.2601102-1-david@gibson.dropbear.id.au> References: <20240827060446.2601102-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: NLNBKK22PEN6BQO6GMFQZVBM4ZCINUVO X-Message-ID-Hash: NLNBKK22PEN6BQO6GMFQZVBM4ZCINUVO 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: Platforms like Linux allow IPv6 sockets to listen for IPv4 connections as well as native IPv6 connections. By doing this we halve the number of listening sockets we need (assuming passt/pasta is listening on the same ports for IPv4 and IPv6). When forwarding many ports (e.g. -u all) this can significantly reduce the amount of kernel memory that passt consumes. We've used such dual stack sockets for TCP since 8e914238b "tcp: Use dual stack sockets for port forwarding when possible". Add similar support for UDP "listening" sockets. Since UDP sockets don't use as much kernel memory as TCP sockets this isn't as big a saving, but it's still significant. When forwarding all TCP and UDP ports for both IPv4 & IPv6 (-t all -u all), this reduces kernel memory usage from ~522 MiB to ~380MiB (kernel version 6.10.6 on Fedora 40, x86_64). Signed-off-by: David Gibson --- udp.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/udp.c b/udp.c index 41a62475..bd9051e1 100644 --- a/udp.c +++ b/udp.c @@ -723,6 +723,25 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af, else uref.pif = PIF_HOST; + if (af == AF_UNSPEC && c->ifi4 && c->ifi6) { + int s; + + /* Attempt to get a dual stack socket */ + if (!ns) { + s = sock_l4(c, AF_UNSPEC, EPOLL_TYPE_UDP_LISTEN, + addr, ifname, port, uref.u32); + udp_splice_init[V4][port] = s < 0 ? -1 : s; + udp_splice_init[V6][port] = s < 0 ? -1 : s; + } else { + s = sock_l4(c, AF_UNSPEC, EPOLL_TYPE_UDP_LISTEN, + &in4addr_loopback, ifname, port, uref.u32); + udp_splice_ns[V4][port] = s < 0 ? -1 : s; + udp_splice_ns[V6][port] = s < 0 ? -1 : s; + } + if (IN_INTERVAL(0, FD_REF_MAX, s)) + return 0; + } + if ((af == AF_INET || af == AF_UNSPEC) && c->ifi4) { if (!ns) { r4 = sock_l4(c, AF_INET, EPOLL_TYPE_UDP_LISTEN, -- 2.46.0