From: Wesley Atwell <[email protected]> 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
