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 9028E4963B2 for ; Wed, 30 Sep 2026 12:29:03 +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=1790771345; cv=none; b=jpawA240J6fdszkmccjnJsrNmuHcIH+5lpuc2rnUQ/I8HmOWntxRN0Zxp+VGA1VkHc3gYngWDSpstz10oEXKQ8BxjXM5mpxn3g5JeWvwj7bk3RfZabdqQv8BEgzWHKES31Zgs+4tPUiaEsrPQrtxA3C1ND23FumgHbPYRMv07og= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790771345; c=relaxed/simple; bh=wG2mMLIJhp0/44FsuwS/QTfDrgmWvzBVXbJyNWr/eTg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SfXHLZSOvpXx7XEQnXQ2l9LL4x5aYy631ycZA8iFySzrY9TSbbpkiLd8etHyqNcYK/hoslOaiy+rCz7TBTD84LBRIVIFZGKbRNo8LQJBpHOjgQEq0glgwgNKBrHP/dwiI6tDBn6jjvLUQZGumQt0Azk4sY+qgkEl9LQZx6xruHI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n9ZilC2D; 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="n9ZilC2D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 531411F000FF; Wed, 30 Sep 2026 12:29:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790771340; bh=FDHBij0drzDs1JEAV7Z7bG01VjSdaIwWnBWeHN1aKOg=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=n9ZilC2DIFyW6x18TWYVVKN47ZVyv5zD45OZ1gtU9m3qA+kEZcBAsloqKpa3s6UrJ g510qirFbKwEVJgUNjj39CDTcafbhaywpI1DO/uJ2n8C7MQjBNVo8fYZVhATkOF+7b /vyU86BlKO6HELhdeFTjBC/OBogiwYX5wZwnpcr/sGcOnmcnqKSQobo/zJ9CFHkcUO K0bttsCCaTMAOb/hVLaRfNUyoT0ecnn53hnODSNTLnryYPepqKWZOflGae9oRC3Wlv uBcBXMhHNnhdPcszGw3+LtPZB+9Nldix8uhnY2KCsCc21+vFIUnAVifJf7uhYrRCbK DKierjnuuUfkg== Message-ID: Date: Wed, 30 Sep 2026 06:28:59 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net 2/2] ipv4: reserve one IP ID per segment for UDP GSO packets Content-Language: en-US To: Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Willem de Bruijn , Ido Schimmel , netdev@vger.kernel.org, edumazet@google.com References: <20260929131247.401104-1-edumazet@kernel.org> <20260929131247.401104-3-edumazet@kernel.org> From: David Ahern In-Reply-To: <20260929131247.401104-3-edumazet@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/29/26 8:12 AM, Eric Dumazet wrote: > @@ -1464,7 +1465,19 @@ struct sk_buff *__ip_make_skb(struct sock *sk, > iph->ttl = ttl; > iph->protocol = sk->sk_protocol; > ip_copy_addrs(iph, fl4); > - ip_select_ident(net, skb, sk); > + > + /* UDP GSO packets are segmented later (see udp_send_skb()): > + * reserve one IP ID per segment. > + */ > + segs = 1; > + if (cork->gso_size) { > + int datalen = skb->len - skb_transport_offset(skb) - > + sizeof(struct udphdr); hard coding a specific transport header in L3 code is crossing layers. > + > + if (datalen > cork->gso_size) > + segs = DIV_ROUND_UP(datalen, cork->gso_size); > + } > + ip_select_ident_segs(net, skb, sk, segs); > > if (opt) { > iph->ihl += opt->optlen >> 2;