f6fee16dbb
Linux currently disable ECN for incoming connections when the SYN requests ECN and the IP header has ECT(0)/ECT(1) set, as some networks were reportedly mangling the ToS byte, hence could later trigger false congestion notifications. RFC8311 §4.3 relaxes RFC3168's requirements such that ECT can be set one TCP control packets (including SYNs). The main benefit of this is the decreased probability of losing a SYN in a congested ECN-capable network (i.e., it avoids the initial 1s timeout). Additionally, this allows the development of newer TCP extensions, such as AccECN. This patch relaxes the previous check, by enabling ECN on incoming connections using SYN+ECT if at least one bit of the reserved flags of the TCP header is set. Such bit would indicate that the sender of the SYN is using a newer TCP feature than what the host implements, such as AccECN, and is thus implementing RFC8311. This enables end-hosts not supporting such extensions to still negociate ECN, and to have some of the benefits of using ECN on control packets. Signed-off-by: Olivier Tilmans <olivier.tilmans@nokia-bell-labs.com> Suggested-by: Bob Briscoe <research@bobbriscoe.net> Cc: Koen De Schepper <koen.de_schepper@nokia-bell-labs.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.