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| -rw-r--r-- | doc/misc/tcp-fast-open | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/doc/misc/tcp-fast-open b/doc/misc/tcp-fast-open new file mode 100644 index 0000000..020ec05 --- /dev/null +++ b/doc/misc/tcp-fast-open @@ -0,0 +1,32 @@ +Copyright (C) Internet Systems Consortium, Inc. ("ISC") + +See COPYRIGHT in the source root or http://isc.org/copyright.html for terms. + +Some systems (Linux, FreeBSD, OS X/macOS and Windows 10) support +the TCP Fast Open (RFC 7413) mechanism in their recent versions. + +BIND 9 supports this on the server side. + +When the TCP_FASTOPEN socket option is defined after the listen() +system call the socket code in the libisc set the option with +the half of the listen backlog (so the fast open maximum queue length +is the half of the pending connection queue length). +Any failure is logged and ignored. + +System specific notes: + - FreeBSD doesn't interpret the argument as a queue length but + only as an on/off switch. + + - Using TCP Fast Open on FreeBSD, as of versions 10.3 and 11.0, requires + compiling a custom kernel and setting the "net.inet.tcp.fastopen.enabled" + sysctl to 1. + + - Apple OS X/macOS allows only 0 or 1 so the code puts 1 for this system. + + - Windows 10 uses a 0/1 char flag? Note that TCP_FASTOPEN is defined + only in SDK 10.0.14393.0 or higher (Visual Studio 2015 requires + extra setting of the "Target Platform Version" in all project + properties). + + - the only other system known to support this is Linux. + |