From: Wesley Atwell <atwellwea@gmail.com>
This series keeps sender-visible TCP receive-window accounting tied to the
scaling basis that was in force when the window was advertised, even if
later receive-side truesize inflation lowers scaling_ratio or the live
receive window retracts below the largest right edge already exposed to the
sender.
After the receive-window retraction changes, the receive path needs to keep
track of two related pieces of sender-visible state:
1. the live advertised receive window
2. the maximum advertised right edge and the basis it was exposed with
This repost snapshots both, uses them to repair receive-buffer backing when
ratio drift would otherwise strand sender-visible space, extends
TCP_REPAIR_WINDOW so repair/restore can round-trip the new state, and adds
truesize-drift coverage through TUN packetdrill tests and netdevsim-based
selftests.
v2:
- repost to net-next and use the [PATCH net-next v2] prefix
- rebase the receive-window accounting changes on top of the retraction
model
- split the series more finely
- snapshot both the live rwnd basis and the max advertised-window basis
- extend TCP_REPAIR_WINDOW to preserve legacy, v1, and current layouts
- add TUN RX truesize injection and packetdrill coverage for ratio drift
- split the generic netdevsim PSP extension cleanup into its own final
patch after the peer RX truesize support
- add the requested ABI/runtime comments at the non-obvious review points
Testing:
- full runtime selftest coverage for netdevsim, tcp_ao, mptcp, and
packetdrill; all runtime suites completed successfully
- tcp_ao completed 24/24 top-level tests, covering 803 passing checks,
6 expected failures, 36 skips, and 0 unexpected failures
- mptcp completed 588 passing checks in aggregate, with 28 skips and
0 unexpected failures
- packetdrill completed 219/219 runtime cases with 0 failures,
including the new tests
- netdevsim completed 18/18 top-level runtime tests with 0 failures,
including the peer RX truesize and related netdevsim coverage used by
this series
Wesley Atwell (14):
tcp: factor receive-memory accounting helpers
tcp: snapshot advertise-time scaling for rcv_wnd
tcp: refresh rcv_wnd snapshots at TCP write sites
tcp: snapshot the maximum advertised receive window
tcp: grow rcvbuf to back scaled-window quantization slack
tcp: regrow rcvbuf when scaling_ratio drops after advertisement
tcp: honor the maximum advertised window after live retraction
tcp: extend TCP_REPAIR_WINDOW for live and max-window snapshots
mptcp: refresh TCP receive-window snapshots on subflows
tcp: expose rmem and backlog in tcp and mptcp rcvbuf_grow tracepoints
selftests: tcp_ao: cover legacy, v1, and retracted repair windows
tun/selftests: add RX truesize injection for TCP window tests
netdevsim: add peer RX truesize support for selftests
netdevsim: release pinned PSP ext on drop paths
.../networking/net_cachelines/tcp_sock.rst | 2 +
drivers/net/netdevsim/netdev.c | 156 ++++++-
drivers/net/netdevsim/netdevsim.h | 4 +
drivers/net/tun.c | 65 +++
include/linux/tcp.h | 2 +
include/net/tcp.h | 118 ++++-
include/trace/events/mptcp.h | 11 +-
include/trace/events/tcp.h | 12 +-
include/uapi/linux/if_tun.h | 4 +
include/uapi/linux/tcp.h | 8 +
net/ipv4/tcp.c | 75 ++-
net/ipv4/tcp_fastopen.c | 2 +-
net/ipv4/tcp_input.c | 160 ++++++-
net/ipv4/tcp_minisocks.c | 4 +-
net/ipv4/tcp_output.c | 25 +-
net/mptcp/options.c | 14 +-
net/mptcp/protocol.h | 14 +-
.../selftests/drivers/net/netdevsim/Makefile | 1 +
.../drivers/net/netdevsim/peer-rx-truesize.sh | 426 ++++++++++++++++++
.../tcp_rcv_neg_window_truesize.pkt | 143 ++++++
.../net/packetdrill/tcp_rcv_toobig.pkt | 35 ++
.../packetdrill/tcp_rcv_toobig_default.pkt | 97 ++++
.../tcp_rcv_toobig_default_truesize.pkt | 118 +++++
.../tcp_rcv_wnd_shrink_allowed_truesize.pkt | 49 ++
.../testing/selftests/net/tcp_ao/lib/aolib.h | 83 +++-
.../testing/selftests/net/tcp_ao/lib/repair.c | 18 +-
.../selftests/net/tcp_ao/self-connect.c | 201 ++++++++-
tools/testing/selftests/net/tun.c | 140 +++++-
28 files changed, 1911 insertions(+), 76 deletions(-)
create mode 100755 tools/testing/selftests/drivers/net/netdevsim/peer-rx-truesize.sh
create mode 100644 tools/testing/selftests/net/packetdrill/tcp_rcv_neg_window_truesize.pkt
create mode 100644 tools/testing/selftests/net/packetdrill/tcp_rcv_toobig.pkt
create mode 100644 tools/testing/selftests/net/packetdrill/tcp_rcv_toobig_default.pkt
create mode 100644 tools/testing/selftests/net/packetdrill/tcp_rcv_toobig_default_truesize.pkt
create mode 100644 tools/testing/selftests/net/packetdrill/tcp_rcv_wnd_shrink_allowed_truesize.pkt
base-commit: f807b5b9b89eb9220d034115c272c312251cbcac
--
2.43.0