From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 118973A6B8A for ; Mon, 17 Aug 2026 23:29:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787009385; cv=none; b=Hr2YMaUZsmgkkDJThe5SxALescz90v79xX5uy0KlyvOefze8gvQ67EcexkLUMPnkBipLOznW6A2wHOmddh8gAs9VHR3VFZZJq5udpfQXSxrAa4CC9gQRnnax15LUh7aUUrHdNVHWrLOZcRRVXG3FxnV7zJR0pv9YUwcTDnQtJ+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787009385; c=relaxed/simple; bh=GWTIo9Avn+5Pi+6svs+/ekLOPV2RUTWVi+lvPzHXerg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=YL4RzxJ9NBQH/0/7cDFwz1Z3IXJS9zkDTsEl5kJZhatfeUUrjJckSGdG9Wz0YiAu6U4u6Y9cgH0x6MI+OgH0zybc/FiC7fLWfYQYStRoCI9NWAJlmfV3Z3466xJ05DlRbD1bbP0jzPRK3HA8uvvj7+w1fUWl6nTWj28smatUJsw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XJamuGhj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XJamuGhj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6307E1F000E9; Mon, 17 Aug 2026 23:29:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787009383; bh=oubCngcQy4g59IruCiIeITyEiuscAJmzXuNj9LCTxSo=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=XJamuGhj5cXklcaYEhyg1jpjwDCh2iO73Db6A5MTn2/77IWV/tdfgg8Zwqpy0AnxV Sl7DOVCoDi7QMJUc7ySoBCoua+KtBoEvQheckuKDGK5+uBb8JnuwoN5D6og5RM6kjy bupBzS65sRGNz5oSHnyEz8v9UPejTjV48TMuo482877mHyZDD1Vlriq8Q3tSQog4RZ 4nA4Z/Pa9nKQGDWQMKgdzi7sq5ToKsmGatdFgSlHoabX8gECbdO6MSAQES1Kh06oik tAbrpWHEf+pk5u92hx2MnVfFNtZioonMJ1sK3x9dX4K7lOguAcCcy5ajpUpkA8SFbP A+50+eVr35tsA== Date: Mon, 17 Aug 2026 16:29:42 -0700 From: Jakub Kicinski To: Mariano Baragiola Cc: netdev@vger.kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, willemb@google.com, kuniyu@google.com, littlesmilingcloud@gmail.com Subject: Re: [PATCH] udp: resubmit encapsulation packets on all multicast listeners Message-ID: <20260817162942.4d08f616@kernel.org> In-Reply-To: <20260815141128.1564949-1-mbaragiola@linux.com> References: <20260815141128.1564949-1-mbaragiola@linux.com> 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 Sat, 15 Aug 2026 11:11:28 -0300 Mariano Baragiola wrote: > UDP encapsulation handlers (FOU/GUE and similar) return a positive > protocol number from udp_queue_rcv_skb()/udpv6_queue_rcv_skb() when the > UDP header has been consumed and the packet must be resubmitted to the > IP protocol handler. Unicast paths already propagate that return value. > > Multicast delivery called consume_skb() on every positive return, so the > inner packet was dropped instead of being reinjected. > > Commit 3cb8d4b9bfeb ("udp: fix encapsulation packet resubmit in multicast > deliver") fixed only the primary ("first") socket path on net-next and is > not yet in net. Secondary listeners still clone the skb and drop it on a > positive return, and net itself still drops the primary socket path too. Wait a week, rebase and repost against net. > Resubmit secondary clones inline via ip_protocol_deliver_rcu() / > ip6_protocol_deliver_rcu() (matching the GSO segment path in > udp_queue_rcv_skb()/udpv6_queue_rcv_skb()), and propagate the primary > socket return value with the same IPv4/IPv6 sign convention as the > unicast helpers. Please include in the commit description how the issue was found.