further simplify ALPN selection

This commit is contained in:
Maximilian Hils 2021-06-10 00:18:37 +02:00
parent d47eb7556a
commit 83a46b13b9
2 changed files with 11 additions and 10 deletions

View File

@ -169,18 +169,19 @@ class TlsConfig:
if not server.alpn_offers:
if client.alpn_offers:
if ctx.options.http2:
# We would perfectly support HTTP/1 -> HTTP/2, but we want to keep things on the same protocol
# version. There are some edge cases where we want to mirror the regular server's behavior
# accurately, for example header capitalization.
server.alpn_offers = tuple(client.alpn_offers)
else:
server.alpn_offers = tuple(x for x in client.alpn_offers if x != b"h2")
elif client.tls:
# We would perfectly support HTTP/1 -> HTTP/2, but we want to keep things on the same protocol version.
# There are some edge cases where we want to mirror the regular server's behavior accurately,
# for example header capitalization.
server.alpn_offers = []
elif ctx.options.http2:
server.alpn_offers = tls.HTTP_ALPNS
else:
server.alpn_offers = tls.HTTP1_ALPNS
# We either have no client TLS or a client without ALPN.
# - If the client does use TLS but did not send an ALPN extension, we want to mirror that upstream.
# - If the client does not use TLS, there's no clear-cut answer. As a pragmatic approach, we also do
# not send any ALPN extension in this case, which defaults to whatever protocol we are speaking
# or falls back to HTTP.
server.alpn_offers = []
if not server.cipher_list and ctx.options.ciphers_server:
server.cipher_list = ctx.options.ciphers_server.split(":")

View File

@ -190,8 +190,8 @@ class TestTlsConfig:
assert_alpn(True, tls.HTTP_ALPNS + (b"foo",), tls.HTTP_ALPNS + (b"foo",))
assert_alpn(False, tls.HTTP_ALPNS + (b"foo",), tls.HTTP1_ALPNS + (b"foo",))
assert_alpn(True, [], tls.HTTP_ALPNS)
assert_alpn(False, [], tls.HTTP1_ALPNS)
assert_alpn(True, [], [])
assert_alpn(False, [], [])
ctx.client.timestamp_tls_setup = time.time()
# make sure that we don't upgrade h1 to h2,
# see comment in tlsconfig.py