From: Vincent Mailhol Use NL_SET_ERR_MSG() and NL_SET_ERR_MSG_FMT() to return meaningful error messages to the userland whenever a -EOPNOTSUPP error is returned due to a failed validation of the CAN netlink arguments. Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20250923-canxl-netlink-prep-v4-20-e720d28f66fe@kernel.org Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/netlink.c | 82 ++++++++++++++++++++++++++--------- 1 file changed, 62 insertions(+), 20 deletions(-) diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c index 92d8df13e886..0591406b6f32 100644 --- a/drivers/net/can/dev/netlink.c +++ b/drivers/net/can/dev/netlink.c @@ -64,15 +64,23 @@ static int can_validate_tdc(struct nlattr *data_tdc, bool tdc_auto = tdc_flags & CAN_CTRLMODE_TDC_AUTO_MASK; int err; - /* CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive */ - if (tdc_auto && tdc_manual) + if (tdc_auto && tdc_manual) { + NL_SET_ERR_MSG(extack, + "TDC manual and auto modes are mutually exclusive"); return -EOPNOTSUPP; + } /* If one of the CAN_CTRLMODE_TDC_* flag is set then TDC * must be set and vice-versa */ - if ((tdc_auto || tdc_manual) != !!data_tdc) + if ((tdc_auto || tdc_manual) && !data_tdc) { + NL_SET_ERR_MSG(extack, "TDC parameters are missing"); return -EOPNOTSUPP; + } + if (!(tdc_auto || tdc_manual) && data_tdc) { + NL_SET_ERR_MSG(extack, "TDC mode (auto or manual) is missing"); + return -EOPNOTSUPP; + } /* If providing TDC parameters, at least TDCO is needed. TDCV * is needed if and only if CAN_CTRLMODE_TDC_MANUAL is set @@ -86,15 +94,23 @@ static int can_validate_tdc(struct nlattr *data_tdc, return err; if (tb_tdc[IFLA_CAN_TDC_TDCV]) { - if (tdc_auto) + if (tdc_auto) { + NL_SET_ERR_MSG(extack, + "TDCV is incompatible with TDC auto mode"); return -EOPNOTSUPP; + } } else { - if (tdc_manual) + if (tdc_manual) { + NL_SET_ERR_MSG(extack, + "TDC manual mode requires TDCV"); return -EOPNOTSUPP; + } } - if (!tb_tdc[IFLA_CAN_TDC_TDCO]) + if (!tb_tdc[IFLA_CAN_TDC_TDCO]) { + NL_SET_ERR_MSG(extack, "TDCO is missing"); return -EOPNOTSUPP; + } } return 0; @@ -105,6 +121,7 @@ static int can_validate_databittiming(struct nlattr *data[], int ifla_can_data_bittiming, u32 flags) { struct nlattr *data_tdc; + const char *type; u32 tdc_flags; bool is_on; int err; @@ -120,18 +137,31 @@ static int can_validate_databittiming(struct nlattr *data[], data_tdc = data[IFLA_CAN_TDC]; tdc_flags = flags & CAN_CTRLMODE_FD_TDC_MASK; is_on = flags & CAN_CTRLMODE_FD; + type = "FD"; } else { return -EOPNOTSUPP; /* Place holder for CAN XL */ } if (is_on) { - if (!data[IFLA_CAN_BITTIMING] || !data[ifla_can_data_bittiming]) + if (!data[IFLA_CAN_BITTIMING] || !data[ifla_can_data_bittiming]) { + NL_SET_ERR_MSG_FMT(extack, + "Provide both nominal and %s data bittiming", + type); return -EOPNOTSUPP; - } - - if (data[ifla_can_data_bittiming] || data_tdc) { - if (!is_on) + } + } else { + if (data[ifla_can_data_bittiming]) { + NL_SET_ERR_MSG_FMT(extack, + "%s data bittiming requires CAN %s", + type, type); return -EOPNOTSUPP; + } + if (data_tdc) { + NL_SET_ERR_MSG_FMT(extack, + "%s TDC requires CAN %s", + type, type); + return -EOPNOTSUPP; + } } err = can_validate_bittiming(data, extack, ifla_can_data_bittiming); @@ -178,8 +208,7 @@ static int can_ctrlmode_changelink(struct net_device *dev, { struct can_priv *priv = netdev_priv(dev); struct can_ctrlmode *cm; - u32 maskedflags; - u32 ctrlstatic; + u32 ctrlstatic, maskedflags, notsupp, ctrlstatic_missing; if (!data[IFLA_CAN_CTRLMODE]) return 0; @@ -189,20 +218,28 @@ static int can_ctrlmode_changelink(struct net_device *dev, return -EBUSY; cm = nla_data(data[IFLA_CAN_CTRLMODE]); - maskedflags = cm->flags & cm->mask; ctrlstatic = can_get_static_ctrlmode(priv); + maskedflags = cm->flags & cm->mask; + notsupp = maskedflags & ~(priv->ctrlmode_supported | ctrlstatic); + ctrlstatic_missing = (maskedflags & ctrlstatic) ^ ctrlstatic; - /* check whether provided bits are allowed to be passed */ - if (maskedflags & ~(priv->ctrlmode_supported | ctrlstatic)) + if (notsupp) { + NL_SET_ERR_MSG_FMT(extack, + "requested control mode %s not supported", + can_get_ctrlmode_str(notsupp)); return -EOPNOTSUPP; + } /* do not check for static fd-non-iso if 'fd' is disabled */ if (!(maskedflags & CAN_CTRLMODE_FD)) ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO; - /* make sure static options are provided by configuration */ - if ((maskedflags & ctrlstatic) != ctrlstatic) + if (ctrlstatic_missing) { + NL_SET_ERR_MSG_FMT(extack, + "missing required %s static control mode", + can_get_ctrlmode_str(ctrlstatic_missing)); return -EOPNOTSUPP; + } /* If a top dependency flag is provided, reset all its dependencies */ if (cm->mask & CAN_CTRLMODE_FD) @@ -234,8 +271,10 @@ static int can_tdc_changelink(struct data_bittiming_params *dbt_params, const struct can_tdc_const *tdc_const = dbt_params->tdc_const; int err; - if (!tdc_const) + if (!tdc_const) { + NL_SET_ERR_MSG(extack, "The device does not support TDC"); return -EOPNOTSUPP; + } err = nla_parse_nested(tb_tdc, IFLA_CAN_TDC_MAX, nla, can_tdc_policy, extack); @@ -450,8 +489,11 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[], const unsigned int num_term = priv->termination_const_cnt; unsigned int i; - if (!priv->do_set_termination) + if (!priv->do_set_termination) { + NL_SET_ERR_MSG(extack, + "Termination is not configurable on this device"); return -EOPNOTSUPP; + } /* check whether given value is supported by the interface */ for (i = 0; i < num_term; i++) { -- 2.51.0