From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 436562941B for ; Thu, 11 Apr 2024 15:52:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712850728; cv=none; b=XHViBWlyuRGS2vTqxij1LjVjnHlrwmzg9eOCeFH3IMFlsYEeZrEHT7feEdIb/CmyreTVOnF9eZVk+GPMy1xPqxCqIxfIw5dsPzxrzlY0EmfPU2OOgl1lddkCGRnCmT7tORqzq2ieYaaCo8m/5skdkIQ7Oiz2uNjMwbk4gHObLs0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712850728; c=relaxed/simple; bh=WXVEMBGsq4Evp3kJVq7V3SFlz2NoKb+9imPHtxiMwIY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=IYtqd7QbpR87nfKX++MyPXORKiiXl7g8lOMSp3YGwZiM7b/X+CCymWfA65v97YK0zETrYgX4wF7uAqmuXox1m11koww9Lirei60xCIAJrjqyFmslr5A735bWhTxl0wPauTzb8p5jqobAWRWe4V7lywRdKmapN9Qp59PtsjdiUU8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XJ62lVBy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XJ62lVBy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D4B4C072AA; Thu, 11 Apr 2024 15:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712850727; bh=WXVEMBGsq4Evp3kJVq7V3SFlz2NoKb+9imPHtxiMwIY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XJ62lVByk1wBUz/tl+vEb2YTIy55nBFv5UP+DeyqB5vr5j1M1E9krC0mWjpWnwYSa PiExqjEW4kxdOLgGkiuVXCIbOZIXoF0OQlZQT7iOv8cmE+Bgo/A4hR0lGeXVUSakey KU6mfoCK/bDnh9NlabDJz0IjAt1eytgAkSwjt6HR7W95CuZN0l6/T/++f1oUqEbh4x i8KR3/2G9mddMyj/217XAXZaiqAeWB/ZeNSHLnom1KVgxNkXyL1ALaGfmSHuorS5yf r57ZMWYYbg/+PoMC+WZlBsFFL3WH9ErNnkGM5wZWDbA5uolj9sRfqqK9g6pDVjwOyU gwoN/ulWGJ7JQ== Date: Thu, 11 Apr 2024 08:52:06 -0700 From: Jakub Kicinski To: Ilya Maximets Cc: Eric Dumazet , Stefano Brivio , davem@davemloft.net, netdev@vger.kernel.org, pabeni@redhat.com, jiri@resnulli.us, idosch@idosch.org, johannes@sipsolutions.net, fw@strlen.de, pablo@netfilter.org, Martin Pitt , Paul Holzinger , David Gibson Subject: Re: [PATCH net-next v2 3/3] genetlink: fit NLMSG_DONE into same read() as families Message-ID: <20240411085206.1d127414@kernel.org> In-Reply-To: References: <20240303052408.310064-1-kuba@kernel.org> <20240303052408.310064-4-kuba@kernel.org> <20240315124808.033ff58d@elisabeth> <20240319085545.76445a1e@kernel.org> <20240319104046.203df045@kernel.org> <02b50aae-f0e9-47a4-8365-a977a85975d3@ovn.org> <20240411081610.71818cfc@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 11 Apr 2024 17:39:20 +0200 Ilya Maximets wrote: > nlmsg_type=0x1a /* NLMSG_??? */ --> RTM_GETROUTE > nlmsg_flags=NLM_F_REQUEST|0x300 --> NLM_F_REQUEST|NLM_F_DUMP Thanks! Also: "\x02\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x01\x00\x0a\x01\x01\x02" ^^^^ So it's dumping AF_INET. I'm guessing its also going to dump v6, separately? To fix v4 I think something like this would do (untested): diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 48741352a88a..749baa74eee7 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -1050,6 +1050,11 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb) e++; } } + + /* Don't let NLM_DONE coalesce into a message, even if it could. + * Some user space expects NLM_DONE in a separate recv(). + */ + err = skb->len; out: cb->args[1] = e;