hds.py

#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0

import errno
import os
import random
from typing import Union
from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_raises, KsftSkipEx
from lib.py import CmdExitFailure, EthtoolFamily, NlError
from lib.py import NetDrvEnv
from lib.py import defer, ethtool, ip


def _get_hds_mode(cfg, netnl) -> str:
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'tcp-data-split' not in rings:
        raise KsftSkipEx('tcp-data-split not supported by device')
    return rings['tcp-data-split']


def _xdp_onoff(cfg):
    prog = cfg.net_lib_dir / "xdp_dummy.bpf.o"
    ip("link set dev %s xdp obj %s sec xdp" %
       (cfg.ifname, prog))
    ip("link set dev %s xdp off" % cfg.ifname)


def _ioctl_ringparam_modify(cfg, netnl) -> None:
    """
    Helper for performing a hopefully unimportant IOCTL SET.
    IOCTL does not support HDS, so it should not affect the HDS config.
    """
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')

    if 'tx' not in rings:
        raise KsftSkipEx('setting Tx ring size not supported')

    try:
        ethtool(f"--disable-netlink -G {cfg.ifname} tx {rings['tx'] // 2}")
    except CmdExitFailure as e:
        ethtool(f"--disable-netlink -G {cfg.ifname} tx {rings['tx'] * 2}")
    defer(ethtool, f"-G {cfg.ifname} tx {rings['tx']}")


def get_hds(cfg, netnl) -> None:
    _get_hds_mode(cfg, netnl)


def get_hds_thresh(cfg, netnl) -> None:
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'hds-thresh' not in rings:
        raise KsftSkipEx('hds-thresh not supported by device')


def _hds_reset(cfg, netnl, rings) -> None:
    cur = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})

    arg = {'header': {'dev-index': cfg.ifindex}}
    if cur.get('tcp-data-split') != rings.get('tcp-data-split'):
        # Try to reset to "unknown" first, we don't know if the setting
        # was the default or user chose it. Default seems more likely.
        arg['tcp-data-split'] = "unknown"
        netnl.rings_set(arg)
        cur = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
        if cur['tcp-data-split'] == rings['tcp-data-split']:
            del arg['tcp-data-split']
        else:
            # Try the explicit setting
            arg['tcp-data-split'] = rings['tcp-data-split']
    if cur.get('hds-thresh') != rings.get('hds-thresh'):
        arg['hds-thresh'] = rings['hds-thresh']
    if len(arg) > 1:
        netnl.rings_set(arg)


def _defer_reset_hds(cfg, netnl) -> Union[dict, None]:
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
        if 'hds-thresh' in rings or 'tcp-data-split' in rings:
            defer(_hds_reset, cfg, netnl, rings)
    except NlError as e:
        pass


def set_hds_enable(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'enabled'})
    except NlError as e:
        if e.error == errno.EINVAL:
            raise KsftSkipEx("disabling of HDS not supported by the device")
        elif e.error == errno.EOPNOTSUPP:
            raise KsftSkipEx("ring-set not supported by the device")
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'tcp-data-split' not in rings:
        raise KsftSkipEx('tcp-data-split not supported by device')

    ksft_eq('enabled', rings['tcp-data-split'])

def set_hds_disable(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'tcp-data-split': 'disabled'})
    except NlError as e:
        if e.error == errno.EINVAL:
            raise KsftSkipEx("disabling of HDS not supported by the device")
        elif e.error == errno.EOPNOTSUPP:
            raise KsftSkipEx("ring-set not supported by the device")
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'tcp-data-split' not in rings:
        raise KsftSkipEx('tcp-data-split not supported by device')

    ksft_eq('disabled', rings['tcp-data-split'])

def set_hds_thresh_zero(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': 0})
    except NlError as e:
        if e.error == errno.EINVAL:
            raise KsftSkipEx("hds-thresh-set not supported by the device")
        elif e.error == errno.EOPNOTSUPP:
            raise KsftSkipEx("ring-set not supported by the device")
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'hds-thresh' not in rings:
        raise KsftSkipEx('hds-thresh not supported by device')

    ksft_eq(0, rings['hds-thresh'])

def set_hds_thresh_random(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'hds-thresh' not in rings:
        raise KsftSkipEx('hds-thresh not supported by device')
    if 'hds-thresh-max' not in rings:
        raise KsftSkipEx('hds-thresh-max not defined by device')

    if rings['hds-thresh-max'] < 2:
        raise KsftSkipEx('hds-thresh-max is too small')
    elif rings['hds-thresh-max'] == 2:
        hds_thresh = 1
    else:
        while True:
            hds_thresh = random.randint(1, rings['hds-thresh-max'] - 1)
            if hds_thresh != rings['hds-thresh']:
                break

    try:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': hds_thresh})
    except NlError as e:
        if e.error == errno.EINVAL:
            raise KsftSkipEx("hds-thresh-set not supported by the device")
        elif e.error == errno.EOPNOTSUPP:
            raise KsftSkipEx("ring-set not supported by the device")
    rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    ksft_eq(hds_thresh, rings['hds-thresh'])

def set_hds_thresh_max(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'hds-thresh' not in rings:
        raise KsftSkipEx('hds-thresh not supported by device')
    try:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': rings['hds-thresh-max']})
    except NlError as e:
        if e.error == errno.EINVAL:
            raise KsftSkipEx("hds-thresh-set not supported by the device")
        elif e.error == errno.EOPNOTSUPP:
            raise KsftSkipEx("ring-set not supported by the device")
    rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    ksft_eq(rings['hds-thresh'], rings['hds-thresh-max'])

def set_hds_thresh_gt(cfg, netnl) -> None:
    _defer_reset_hds(cfg, netnl)
    try:
        rings = netnl.rings_get({'header': {'dev-index': cfg.ifindex}})
    except NlError as e:
        raise KsftSkipEx('ring-get not supported by device')
    if 'hds-thresh' not in rings:
        raise KsftSkipEx('hds-thresh not supported by device')
    if 'hds-thresh-max' not in rings:
        raise KsftSkipEx('hds-thresh-max not defined by device')
    hds_gt = rings['hds-thresh-max'] + 1
    with ksft_raises(NlError) as e:
        netnl.rings_set({'header': {'dev-index': cfg.ifindex}, 'hds-thresh': hds_gt})
    ksft_eq(e.exception.nl_msg.error, -errno.EINVAL)


def set_xdp(cfg, netnl) -> None:
    """
    Enable single-buffer XDP on the device.
    When HDS is in "auto" / UNKNOWN mode, XDP installation should work.
    """
    mode = _get_hds_mode(cfg, netnl)
    if mode == 'enabled':
        _defer_reset_hds(cfg, netnl)
        netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                         'tcp-data-split': 'unknown'})

    _xdp_onoff(cfg)


def enabled_set_xdp(cfg, netnl) -> None:
    """
    Enable single-buffer XDP on the device.
    When HDS is in "enabled" mode, XDP installation should not work.
    """
    _get_hds_mode(cfg, netnl)
    netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                     'tcp-data-split': 'enabled'})

    defer(netnl.rings_set, {'header': {'dev-index': cfg.ifindex},
                            'tcp-data-split': 'unknown'})

    with ksft_raises(CmdExitFailure) as e:
        _xdp_onoff(cfg)


def set_xdp(cfg, netnl) -> None:
    """
    Enable single-buffer XDP on the device.
    When HDS is in "auto" / UNKNOWN mode, XDP installation should work.
    """
    mode = _get_hds_mode(cfg, netnl)
    if mode == 'enabled':
        netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                         'tcp-data-split': 'unknown'})

    _xdp_onoff(cfg)


def enabled_set_xdp(cfg, netnl) -> None:
    """
    Enable single-buffer XDP on the device.
    When HDS is in "enabled" mode, XDP installation should not work.
    """
    _get_hds_mode(cfg, netnl)  # Trigger skip if not supported

    netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                     'tcp-data-split': 'enabled'})
    defer(netnl.rings_set, {'header': {'dev-index': cfg.ifindex},
                            'tcp-data-split': 'unknown'})

    with ksft_raises(CmdExitFailure) as e:
        _xdp_onoff(cfg)


def ioctl(cfg, netnl) -> None:
    mode1 = _get_hds_mode(cfg, netnl)
    _ioctl_ringparam_modify(cfg, netnl)
    mode2 = _get_hds_mode(cfg, netnl)

    ksft_eq(mode1, mode2)


def ioctl_set_xdp(cfg, netnl) -> None:
    """
    Like set_xdp(), but we perturb the settings via the legacy ioctl.
    """
    mode = _get_hds_mode(cfg, netnl)
    if mode == 'enabled':
        netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                         'tcp-data-split': 'unknown'})

    _ioctl_ringparam_modify(cfg, netnl)

    _xdp_onoff(cfg)


def ioctl_enabled_set_xdp(cfg, netnl) -> None:
    """
    Enable single-buffer XDP on the device.
    When HDS is in "enabled" mode, XDP installation should not work.
    """
    _get_hds_mode(cfg, netnl)  # Trigger skip if not supported

    netnl.rings_set({'header': {'dev-index': cfg.ifindex},
                     'tcp-data-split': 'enabled'})
    defer(netnl.rings_set, {'header': {'dev-index': cfg.ifindex},
                            'tcp-data-split': 'unknown'})

    with ksft_raises(CmdExitFailure) as e:
        _xdp_onoff(cfg)


def main() -> None:
    with NetDrvEnv(__file__, queue_count=3) as cfg:
        ksft_run([get_hds,
                  get_hds_thresh,
                  set_hds_disable,
                  set_hds_enable,
                  set_hds_thresh_random,
                  set_hds_thresh_zero,
                  set_hds_thresh_max,
                  set_hds_thresh_gt,
                  set_xdp,
                  enabled_set_xdp,
                  ioctl,
                  ioctl_set_xdp,
                  ioctl_enabled_set_xdp],
                 args=(cfg, EthtoolFamily()))
    ksft_exit()

if __name__ == "__main__":
    main()