From patchwork Wed Jan 31 12:05:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislaw Gruszka X-Patchwork-Id: 13539435 X-Patchwork-Delegate: kuba@kernel.org Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AF7F7BB06; Wed, 31 Jan 2024 13:09:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.8 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706706592; cv=none; b=koAXf8qaci4j1qnOZTpo9kw6r5W3Kdqo32D670zMYO9iBSo7CYRx5OsOxMCKqbBSNc96SUG0Fs/U+ixVZTnlceGRkN6zSJffEk810woObph1EDa1cGHFISwoBXBkWQLi5OmRWDZbztZV9wmkAQTpU+B1zClXq+wZzYmdEP71HI8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706706592; c=relaxed/simple; bh=JX0N/7ypdkFlnA58ZmbSsHLuhJ9NA5OC0DOrMAeMuvk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Y+GwX8IzCPgy2yMm4PQsN/ZA273kE0Q+ym8+Qdu2B6iE2s+/jkUKaNLaARxMaz9CuIVZw0DFcZxyvDgM0qg+950U7ZFyo2bszwq/W4xwJWHZpv1TAC9AnK03D61VGg7w7LsmZs1EC+rNDLobfMbanaJlPXUYWNswhZqj7bjA/xI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=iCGrseRB; arc=none smtp.client-ip=192.198.163.8 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="iCGrseRB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1706706590; x=1738242590; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=JX0N/7ypdkFlnA58ZmbSsHLuhJ9NA5OC0DOrMAeMuvk=; b=iCGrseRBmbWSt/CD92xmR8reF2SlgdwmoqQrqa/KP9eUvxpBIwQinpR9 nVvQPem3LD2b6GwjPKpAiEqCqw2CVWZfK6shHEdVv0sbmsiyPmIToHx2X Xkwjv8lW0eqm6mNASIfi3S4zWMA2mBo7jtb3KlwBuofsnPlFJnKh08BeT BYzvJMh28rAeFxma2LSSni3iuWgJX2wMuFi4NJ+xOuSX/KrAcjQCXJivT V3S+WxXFiemZuM0539IoQRcBhK2nPdWPJI1Ws4SxwI1frCFtAVd42uswb f6u9nwtjczIHb4SSyUb3aG/b1zXXVZGtDqjqgDtCWJHdRn+dftwhk+/8i g==; X-IronPort-AV: E=McAfee;i="6600,9927,10969"; a="17126949" X-IronPort-AV: E=Sophos;i="6.05,231,1701158400"; d="scan'208";a="17126949" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jan 2024 05:09:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10969"; a="858816182" X-IronPort-AV: E=Sophos;i="6.05,231,1701158400"; d="scan'208";a="858816182" Received: from sgruszka-mobl.ger.corp.intel.com (HELO localhost) ([10.252.43.19]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jan 2024 05:09:41 -0800 From: Stanislaw Gruszka To: linux-pm@vger.kernel.org Cc: "Rafael J. Wysocki" , Srinivas Pandruvada , Ricardo Neri , Daniel Lezcano , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org Subject: [PATCH 1/3] netlink: Add notifier when changing netlink socket membership Date: Wed, 31 Jan 2024 13:05:33 +0100 Message-Id: <20240131120535.933424-2-stanislaw.gruszka@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240131120535.933424-1-stanislaw.gruszka@linux.intel.com> References: <20240131120535.933424-1-stanislaw.gruszka@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Add notification when adding/removing multicast group to/from client socket via setsockopt() syscall. It can be used with conjunction with netlink_has_listeners() to check if consumers of netlink multicast messages emerge or disappear. A client can call netlink_register_notifier() to register a callback. In the callback check for state NETLINK_CHANGE and NETLINK_URELEASE to get notification for change in the netlink socket membership. Thus, a client can now send events only when there are active consumers, preventing unnecessary work when none exist. Signed-off-by: Stanislaw Gruszka --- include/linux/notifier.h | 1 + net/netlink/af_netlink.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/include/linux/notifier.h b/include/linux/notifier.h index 45702bdcbceb..8f5a5eed1e0e 100644 --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -227,6 +227,7 @@ static inline int notifier_to_errno(int ret) /* Virtual Terminal events are defined in include/linux/vt.h. */ #define NETLINK_URELEASE 0x0001 /* Unicast netlink socket released */ +#define NETLINK_CHANGE 0x0002 /* Changed membership of netlink socket */ /* Console keyboard events. * Note: KBD_KEYCODE is always sent before KBD_UNBOUND_KEYCODE, KBD_UNICODE and diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index eb086b06d60d..674af2cb0f12 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1680,6 +1680,11 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, case NETLINK_ADD_MEMBERSHIP: case NETLINK_DROP_MEMBERSHIP: { int err; + struct netlink_notify n = { + .net = sock_net(sk), + .protocol = sk->sk_protocol, + .portid = nlk->portid, + }; if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV)) return -EPERM; @@ -1700,6 +1705,7 @@ static int netlink_setsockopt(struct socket *sock, int level, int optname, if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind) nlk->netlink_unbind(sock_net(sk), val); + blocking_notifier_call_chain(&netlink_chain, NETLINK_CHANGE, &n); break; } case NETLINK_BROADCAST_ERROR: