add if-range logic

[gquintard]

No description provided.

[Dridi]

If anything, the comments referencing the RFC should use the same format as h2 comments so that we can have coverage here: https://varnish-cache.org/rfc/

[nigoroll]

@gquintard I think @Dridi wants you to put the rfc comment in the format used here:

varnish-cache/bin/varnishd/http2/cache_http2_proto.c

Line 275 in bea1da6

if (h2->rxf_len != 8) // rfc7540,l,2364,2366

[nigoroll]

because the OA_LASTMODIFIED question is independent of the rest of this PR and because Dridi will insist on the RFC ref comments, there is nothing which should hold back my OK

[gquintard]

@Dridi, RFC coverage added, let me know if you want more
@nigoroll, I'll want for you for #3118

Note that adding RFC coverage made me realize the code was wrong:

Note that this comparison by exact match,
including when the validator is an HTTP-date, differs from the
"earlier than or equal to" comparison used when evaluating an
If-Unmodified-Since conditional.

So I amended the code accordingly

[nigoroll]

@nigoroll, I'll want for you for #3118

I do not understand want. Do you mean wait?

[gquintard]

@nigoroll, I'll want for you for #3118

I do not understand want. Do you mean wait?

That's what I meant, keyboards are hard...

[nigoroll]

thx!