receivers cannot enforce datagram padding (though they may drop) #4254
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…oes not meet the padding requirements
draft-ietf-quic-transport.md
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| @@ -4085,6 +4085,13 @@ UDP datagrams MUST NOT be fragmented at the IP layer. In IPv4 | |||
| ({{!IPv4=RFC0791}}), the DF bit MUST be set if possible, to prevent | |||
| fragmentation on the path. | |||
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| Even though datagrams with certain properties are required to be padded, the | |||
| size of the datagram is not authenticated, and endpoints might send coalesced | |||
| packets after the handshake is confirmed (see {{packet-coalesce}}). Therefore, | |||
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Once the handshake is confirmed, Handshake keys are dropped. From that point on, it's not possible to send coalesced packets any more.
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Once the handshake is confirmed, Handshake keys are dropped. From that point on, it's not possible to send coalesced packets any more.
That's not true. Use of handshake packets is explicitly allowed post-handshake; see
https://quicwg.org/base-drafts/draft-ietf-quic-transport.html#name-pmtu-probes-containing-sour.
The reason the reference currently points to packet-coalesce is because it's more generic (and also contains reference to post-handshake PMTUD), but the reference can be specific if that's others' preference.
Co-authored-by: Martin Thomson <mt@lowentropy.net>
Co-authored-by: Martin Thomson <mt@lowentropy.net>
Co-authored-by: Martin Thomson <mt@lowentropy.net>
Co-authored-by: ianswett <ianswett@users.noreply.github.com>
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@larseggert @LPardue: Merging this, since the plan is to do consensus as part of LC. |
Closes #4253, by adding generic "MUST NOT close, MAY discard packets" rule.