QUIC: ignore duplicate PATH_CHALLENGE frames. According to RFC 9000, an endpoint SHOULD NOT send multiple PATH_CHALLENGE frames in a single packet. The change adds a check to enforce this claim to optimize server behavior. Previously each PATH_CHALLENGE always resulted in a single response datagram being sent to client. The effect of this was however limited by QUIC flood protection. Also, PATH_CHALLENGE is explicitly disabled in Initial and Handshake levels, see RFC 9000, Table 3. However, technically it may be sent by client in 0-RTT over a new path without actual migration, even though the migration itself is prohibited during handshake. This allows client to coalesce multiple 0-RTT packets each carrying a PATH_CHALLENGE and end up with multiple PATH_CHALLENGEs per datagram. This again leads to suboptimal behavior, see above. Since the purpose of sending PATH_CHALLENGE frames in 0-RTT is unclear, these frames are now only allowed in 1-RTT. For 0-RTT they are silently ignored.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


all:
	cd $(OPENSSL)

	perl Configure BC-32 no-shared --prefix=openssl $(OPENSSL_OPT)

	ms\do_nasm

	$(MAKE) -f ms\bcb.mak
	$(MAKE) -f ms\bcb.mak install

	# Borland's make does not expand "[ch]" in
	#    copy "inc32\openssl\*.[ch]" "openssl\include\openssl"
	copy inc32\openssl\*.h openssl\include\openssl