Re: [quicwg/base-drafts] Allow ClientHello to span multiple QUIC packets (#3045)
Marten Seemann <notifications@github.com> Tue, 17 September 2019 08:45 UTC
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Subject: Re: [quicwg/base-drafts] Allow ClientHello to span multiple QUIC packets (#3045)
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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
- [quicwg/base-drafts] Allow ClientHello to span mu… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Marten Seemann
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Nick Banks
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Dmitri Tikhonov
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Kazuho Oku
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Nick Banks
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Kazuho Oku
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Nick Banks
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Kazuho Oku
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Martin Thomson
- Re: [quicwg/base-drafts] Allow ClientHello to spa… MikkelFJ
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Christopher Wood
- Re: [quicwg/base-drafts] Allow ClientHello to spa… MikkelFJ
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… MikkelFJ
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Martin Thomson
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… ianswett
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… David Schinazi
- Re: [quicwg/base-drafts] Allow ClientHello to spa… ianswett
- Re: [quicwg/base-drafts] Allow ClientHello to spa… ekr
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Mike Bishop
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Martin Thomson
- Re: [quicwg/base-drafts] Allow ClientHello to spa… Martin Thomson