Return-Path: X-Original-To: quic-issues@ietfa.amsl.com Delivered-To: quic-issues@ietfa.amsl.com Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C93F5120104 for ; Tue, 17 Sep 2019 01:45:38 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -7.899 X-Spam-Level: X-Spam-Status: No, score=-7.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id d6k7ndiyaRoZ for ; Tue, 17 Sep 2019 01:45:36 -0700 (PDT) Received: from out-19.smtp.github.com (out-19.smtp.github.com [192.30.252.202]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id A49591200FF for ; Tue, 17 Sep 2019 01:45:36 -0700 (PDT) Received: from github-lowworker-56fcc46.va3-iad.github.net (github-lowworker-56fcc46.va3-iad.github.net [10.48.102.32]) by smtp.github.com (Postfix) with ESMTP id BC886520038 for ; Tue, 17 Sep 2019 01:45:35 -0700 (PDT) Date: Tue, 17 Sep 2019 01:45:35 -0700 From: Marten Seemann Reply-To: quicwg/base-drafts To: quicwg/base-drafts Cc: Subscribed Message-ID: In-Reply-To: References: Subject: Re: [quicwg/base-drafts] Allow ClientHello to span multiple QUIC packets (#3045) Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="--==_mimepart_5d809d2fae666_58473fe89aacd95c3137d1"; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: list X-GitHub-Sender: marten-seemann X-GitHub-Recipient: quic-issues X-GitHub-Reason: subscribed X-Auto-Response-Suppress: All X-GitHub-Recipient-Address: quic-issues@ietf.org Archived-At: X-BeenThere: quic-issues@ietf.org X-Mailman-Version: 2.1.29 List-Id: Notification list for GitHub issues related to the QUIC WG List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Sep 2019 08:45:39 -0000 ----==_mimepart_5d809d2fae666_58473fe89aacd95c3137d1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit marten-seemann commented on this pull request. > @@ -565,11 +565,19 @@ older than 1.3 is negotiated. ## ClientHello Size {#clienthello-size} -QUIC requires that the first Initial packet from a client contain an entire -cryptographic handshake message, which for TLS is the ClientHello. Though a -packet larger than 1200 bytes might be supported by the path, a client improves -the likelihood that a packet is accepted if it ensures that the first -ClientHello message is small enough to stay within this limit. +The first Initial packet from a client starts with its first cryptographic +handshake message, which for TLS is the ClientHello. Servers might need to +parse the entire ClientHello (e.g., to access extensions such as Server Name +Identification (SNI) or Application Layer Protocol Negotiation (ALPN)) in order +to decide whether to accept the new incoming QUIC connection. If the +ClientHello spans multiple Initial packets, such servers would need to buffer +the first received fragments, which could consume excessive resources if the +client's address has not yet been validated. To avoid this, servers MAY use The resources are consumed either way, but if the client's address has not yet been validated, a server might not be willing to commit those resources. > -cryptographic handshake message, which for TLS is the ClientHello. Though a -packet larger than 1200 bytes might be supported by the path, a client improves -the likelihood that a packet is accepted if it ensures that the first -ClientHello message is small enough to stay within this limit. +The first Initial packet from a client starts with its first cryptographic +handshake message, which for TLS is the ClientHello. Servers might need to +parse the entire ClientHello (e.g., to access extensions such as Server Name +Identification (SNI) or Application Layer Protocol Negotiation (ALPN)) in order +to decide whether to accept the new incoming QUIC connection. If the +ClientHello spans multiple Initial packets, such servers would need to buffer +the first received fragments, which could consume excessive resources if the +client's address has not yet been validated. To avoid this, servers MAY use +the Retry feature (see Section 8.1 of {{QUIC-TRANSPORT}}) to only buffer +partial ClientHellos from clients with a validated address. Though a packet +larger than 1200 bytes might be supported by the path, a client improves the +likelihood that a packet is accepted if it ensures that the first ClientHello s/is accepted/isn't dropped while in transit/ -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/quicwg/base-drafts/pull/3045#pullrequestreview-289105392 ----==_mimepart_5d809d2fae666_58473fe89aacd95c3137d1 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit

@marten-seemann commented on this pull request.

In draft-ietf-quic-tls.md:

> @@ -565,11 +565,19 @@ older than 1.3 is negotiated.
 
 ## ClientHello Size {#clienthello-size}
 
-QUIC requires that the first Initial packet from a client contain an entire
-cryptographic handshake message, which for TLS is the ClientHello.  Though a
-packet larger than 1200 bytes might be supported by the path, a client improves
-the likelihood that a packet is accepted if it ensures that the first
-ClientHello message is small enough to stay within this limit.
+The first Initial packet from a client starts with its first cryptographic
+handshake message, which for TLS is the ClientHello.  Servers might need to
+parse the entire ClientHello (e.g., to access extensions such as Server Name
+Identification (SNI) or Application Layer Protocol Negotiation (ALPN)) in order
+to decide whether to accept the new incoming QUIC connection.  If the
+ClientHello spans multiple Initial packets, such servers would need to buffer
+the first received fragments, which could consume excessive resources if the
+client's address has not yet been validated.  To avoid this, servers MAY use

The resources are consumed either way, but if the client's address has not yet been validated, a server might not be willing to commit those resources.

In draft-ietf-quic-tls.md:

> -cryptographic handshake message, which for TLS is the ClientHello.  Though a
-packet larger than 1200 bytes might be supported by the path, a client improves
-the likelihood that a packet is accepted if it ensures that the first
-ClientHello message is small enough to stay within this limit.
+The first Initial packet from a client starts with its first cryptographic
+handshake message, which for TLS is the ClientHello.  Servers might need to
+parse the entire ClientHello (e.g., to access extensions such as Server Name
+Identification (SNI) or Application Layer Protocol Negotiation (ALPN)) in order
+to decide whether to accept the new incoming QUIC connection.  If the
+ClientHello spans multiple Initial packets, such servers would need to buffer
+the first received fragments, which could consume excessive resources if the
+client's address has not yet been validated.  To avoid this, servers MAY use
+the Retry feature (see Section 8.1 of {{QUIC-TRANSPORT}}) to only buffer
+partial ClientHellos from clients with a validated address.  Though a packet
+larger than 1200 bytes might be supported by the path, a client improves the
+likelihood that a packet is accepted if it ensures that the first ClientHello

s/is accepted/isn't dropped while in transit/

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub, or mute the thread.

----==_mimepart_5d809d2fae666_58473fe89aacd95c3137d1--