Merge branch 'net-ethtool-support-including-flow-label-in-the-flow-hash-for-rss'

Jakub Kicinski says:

====================
net: ethtool: support including Flow Label in the flow hash for RSS

Add support for using IPv6 Flow Label in Rx hash computation
and therefore RSS queue selection.

v3: https://lore.kernel.org/20250724015101.186608-1-kuba@kernel.org
v2:  https://lore.kernel.org/20250722014915.3365370-1-kuba@kernel.org
RFC: https://lore.kernel.org/20250609173442.1745856-1-kuba@kernel.org
====================

Link: https://patch.msgid.link/20250811234212.580748-1-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

11 files changed, 233 insertions, 18 deletions

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 1bc1bd7d33c2..7a7594713f1f 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -205,6 +205,9 @@ definitions:
       -
         name: gtp-teid
       -
+        name: ip6-fl
+        doc: IPv6 Flow Label
+      -
         name: discard
         value: 31
 
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 5578ddcb465d..ab74c71c4557 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -6957,6 +6957,8 @@ static int bnxt_hwrm_vnic_qcaps(struct bnxt *bp)
 			bp->rss_cap |= BNXT_RSS_CAP_ESP_V4_RSS_CAP;
 		if (flags & VNIC_QCAPS_RESP_FLAGS_RSS_IPSEC_ESP_SPI_IPV6_CAP)
 			bp->rss_cap |= BNXT_RSS_CAP_ESP_V6_RSS_CAP;
+		if (flags & VNIC_QCAPS_RESP_FLAGS_RSS_IPV6_FLOW_LABEL_CAP)
+			bp->rss_cap |= BNXT_RSS_CAP_IPV6_FLOW_LABEL_RSS_CAP;
 		if (flags & VNIC_QCAPS_RESP_FLAGS_RE_FLUSH_CAP)
 			bp->fw_cap |= BNXT_FW_CAP_VNIC_RE_FLUSH;
 	}
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index fda0d3cc6227..40ae34923511 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -2407,6 +2407,7 @@ struct bnxt {
 #define BNXT_RSS_CAP_ESP_V4_RSS_CAP		BIT(6)
 #define BNXT_RSS_CAP_ESP_V6_RSS_CAP		BIT(7)
 #define BNXT_RSS_CAP_MULTI_RSS_CTX		BIT(8)
+#define BNXT_RSS_CAP_IPV6_FLOW_LABEL_RSS_CAP	BIT(9)
 
 	u8			rss_hash_key[HW_HASH_KEY_SIZE];
 	u8			rss_hash_key_valid:1;
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index 1b37612b1c01..68a4ee9f69b1 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -1584,6 +1584,8 @@ static u64 get_ethtool_ipv6_rss(struct bnxt *bp)
 {
 	if (bp->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6)
 		return RXH_IP_SRC | RXH_IP_DST;
+	if (bp->rss_hash_cfg & VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6_FLOW_LABEL)
+		return RXH_IP_SRC | RXH_IP_DST | RXH_IP6_FL;
 	return 0;
 }
 
@@ -1662,13 +1664,18 @@ static int bnxt_set_rxfh_fields(struct net_device *dev,
 
 	if (cmd->data == RXH_4TUPLE)
 		tuple = 4;
-	else if (cmd->data == RXH_2TUPLE)
+	else if (cmd->data == RXH_2TUPLE ||
+		 cmd->data == (RXH_2TUPLE | RXH_IP6_FL))
 		tuple = 2;
 	else if (!cmd->data)
 		tuple = 0;
 	else
 		return -EINVAL;
 
+	if (cmd->data & RXH_IP6_FL &&
+	    !(bp->rss_cap & BNXT_RSS_CAP_IPV6_FLOW_LABEL_RSS_CAP))
+		return -EINVAL;
+
 	if (cmd->flow_type == TCP_V4_FLOW) {
 		rss_hash_cfg &= ~VNIC_RSS_CFG_REQ_HASH_TYPE_TCP_IPV4;
 		if (tuple == 4)
@@ -1732,10 +1739,15 @@ static int bnxt_set_rxfh_fields(struct net_device *dev,
 	case AH_V6_FLOW:
 	case ESP_V6_FLOW:
 	case IPV6_FLOW:
-		if (tuple == 2)
+		rss_hash_cfg &= ~(VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6 |
+				  VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6_FLOW_LABEL);
+		if (!tuple)
+			break;
+		if (cmd->data & RXH_IP6_FL)
+			rss_hash_cfg |=
+				VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6_FLOW_LABEL;
+		else if (tuple == 2)
 			rss_hash_cfg |= VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6;
-		else if (!tuple)
-			rss_hash_cfg &= ~VNIC_RSS_CFG_REQ_HASH_TYPE_IPV6;
 		break;
 	}
 
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
index dc7ba8d5fc43..461c8661eb93 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
@@ -1310,7 +1310,7 @@ fbnic_get_rss_hash_opts(struct net_device *netdev,
 #define FBNIC_L2_HASH_OPTIONS \
 	(RXH_L2DA | RXH_DISCARD)
 #define FBNIC_L3_HASH_OPTIONS \
-	(FBNIC_L2_HASH_OPTIONS | RXH_IP_SRC | RXH_IP_DST)
+	(FBNIC_L2_HASH_OPTIONS | RXH_IP_SRC | RXH_IP_DST | RXH_IP6_FL)
 #define FBNIC_L4_HASH_OPTIONS \
 	(FBNIC_L3_HASH_OPTIONS | RXH_L4_B_0_1 | RXH_L4_B_2_3)
 
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
index 8ff07b5562e3..a4dc1024c0c2 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_rpc.c
@@ -71,6 +71,8 @@ u16 fbnic_flow_hash_2_rss_en_mask(struct fbnic_net *fbn, int flow_type)
 	rss_en_mask |= FBNIC_FH_2_RSSEM_BIT(IP_DST, IP_DST, flow_hash);
 	rss_en_mask |= FBNIC_FH_2_RSSEM_BIT(L4_B_0_1, L4_SRC, flow_hash);
 	rss_en_mask |= FBNIC_FH_2_RSSEM_BIT(L4_B_2_3, L4_DST, flow_hash);
+	rss_en_mask |= FBNIC_FH_2_RSSEM_BIT(IP6_FL, OV6_FL_LBL, flow_hash);
+	rss_en_mask |= FBNIC_FH_2_RSSEM_BIT(IP6_FL, IV6_FL_LBL, flow_hash);
 
 	return rss_en_mask;
 }
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 9e9afdd1238a..8bd5ea5469d9 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -2380,6 +2380,7 @@ enum {
 #define	RXH_L4_B_0_1	(1 << 6) /* src port in case of TCP/UDP/SCTP */
 #define	RXH_L4_B_2_3	(1 << 7) /* dst port in case of TCP/UDP/SCTP */
 #define	RXH_GTP_TEID	(1 << 8) /* teid in case of GTP */
+#define	RXH_IP6_FL	(1 << 9) /* IPv6 flow label */
 #define	RXH_DISCARD	(1 << 31)
 
 #define	RX_CLS_FLOW_DISC	0xffffffffffffffffULL
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 43a7854e784e..0b2a4d0573b3 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1014,6 +1014,28 @@ static bool flow_type_hashable(u32 flow_type)
 	return false;
 }
 
+static bool flow_type_v6(u32 flow_type)
+{
+	switch (flow_type) {
+	case TCP_V6_FLOW:
+	case UDP_V6_FLOW:
+	case SCTP_V6_FLOW:
+	case AH_ESP_V6_FLOW:
+	case AH_V6_FLOW:
+	case ESP_V6_FLOW:
+	case IPV6_FLOW:
+	case GTPU_V6_FLOW:
+	case GTPC_V6_FLOW:
+	case GTPC_TEID_V6_FLOW:
+	case GTPU_EH_V6_FLOW:
+	case GTPU_UL_V6_FLOW:
+	case GTPU_DL_V6_FLOW:
+		return true;
+	}
+
+	return false;
+}
+
 /* When adding a new type, update the assert and, if it's hashable, add it to
  * the flow_type_hashable switch case.
  */
@@ -1077,6 +1099,9 @@ ethtool_set_rxfh_fields(struct net_device *dev, u32 cmd, void __user *useraddr)
 	if (rc)
 		return rc;
 
+	if (info.data & RXH_IP6_FL && !flow_type_v6(info.flow_type))
+		return -EINVAL;
+
 	if (info.flow_type & FLOW_RSS && info.rss_context &&
 	    !ops->rxfh_per_ctx_fields)
 		return -EINVAL;
diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c
index 992e98abe9dd..202d95e8bf3e 100644
--- a/net/ethtool/rss.c
+++ b/net/ethtool/rss.c
@@ -536,35 +536,36 @@ void ethtool_rss_notify(struct net_device *dev, u32 type, u32 rss_context)
 #define RFH_MASK (RXH_L2DA | RXH_VLAN | RXH_IP_SRC | RXH_IP_DST | \
 		  RXH_L3_PROTO | RXH_L4_B_0_1 | RXH_L4_B_2_3 |	  \
 		  RXH_GTP_TEID | RXH_DISCARD)
+#define RFH_MASKv6 (RFH_MASK | RXH_IP6_FL)
 
 static const struct nla_policy ethnl_rss_flows_policy[] = {
 	[ETHTOOL_A_FLOW_ETHER]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
 	[ETHTOOL_A_FLOW_IP4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_IP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_IP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_TCP4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
 	[ETHTOOL_A_FLOW_UDP4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
 	[ETHTOOL_A_FLOW_SCTP4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
 	[ETHTOOL_A_FLOW_AH_ESP4]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_TCP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_UDP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_SCTP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_AH_ESP6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_TCP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
+	[ETHTOOL_A_FLOW_UDP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
+	[ETHTOOL_A_FLOW_SCTP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
+	[ETHTOOL_A_FLOW_AH_ESP6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_AH4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
 	[ETHTOOL_A_FLOW_ESP4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_AH6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_ESP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_AH6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
+	[ETHTOOL_A_FLOW_ESP6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPU4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPU6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPU6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPC4]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPC6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPC6]		= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPC_TEID4]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPC_TEID6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPC_TEID6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPU_EH4]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPU_EH6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPU_EH6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPU_UL4]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPU_UL6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPU_UL6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 	[ETHTOOL_A_FLOW_GTPU_DL4]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
-	[ETHTOOL_A_FLOW_GTPU_DL6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASK),
+	[ETHTOOL_A_FLOW_GTPU_DL6]	= NLA_POLICY_MASK(NLA_UINT, RFH_MASKv6),
 };
 
 const struct nla_policy ethnl_rss_set_policy[ETHTOOL_A_RSS_FLOW_HASH + 1] = {
diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
index fdc97355588c..5159fd34cb33 100644
--- a/tools/testing/selftests/drivers/net/hw/Makefile
+++ b/tools/testing/selftests/drivers/net/hw/Makefile
@@ -18,6 +18,7 @@ TEST_PROGS = \
 	pp_alloc_fail.py \
 	rss_api.py \
 	rss_ctx.py \
+	rss_flow_label.py \
 	rss_input_xfrm.py \
 	tso.py \
 	xsk_reconfig.py \
diff --git a/tools/testing/selftests/drivers/net/hw/rss_flow_label.py b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py
new file mode 100755
index 000000000000..6fa95fe27c47
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/hw/rss_flow_label.py
@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+"""
+Tests for RSS hashing on IPv6 Flow Label.
+"""
+
+import glob
+import os
+import socket
+from lib.py import CmdExitFailure
+from lib.py import ksft_run, ksft_exit, ksft_eq, ksft_ge, ksft_in, \
+    ksft_not_in, ksft_raises, KsftSkipEx
+from lib.py import bkg, cmd, defer, fd_read_timeout, rand_port
+from lib.py import NetDrvEpEnv
+
+
+def _check_system(cfg):
+    if not hasattr(socket, "SO_INCOMING_CPU"):
+        raise KsftSkipEx("socket.SO_INCOMING_CPU was added in Python 3.11")
+
+    qcnt = len(glob.glob(f"/sys/class/net/{cfg.ifname}/queues/rx-*"))
+    if qcnt < 2:
+        raise KsftSkipEx(f"Local has only {qcnt} queues")
+
+    for f in [f"/sys/class/net/{cfg.ifname}/queues/rx-0/rps_flow_cnt",
+              f"/sys/class/net/{cfg.ifname}/queues/rx-0/rps_cpus"]:
+        try:
+            with open(f, 'r') as fp:
+                setting = fp.read().strip()
+                # CPU mask will be zeros and commas
+                if setting.replace("0", "").replace(",", ""):
+                    raise KsftSkipEx(f"RPS/RFS is configured: {f}: {setting}")
+        except FileNotFoundError:
+            pass
+
+    # 1 is the default, if someone changed it we probably shouldn"t mess with it
+    af = cmd("cat /proc/sys/net/ipv6/auto_flowlabels", host=cfg.remote).stdout
+    if af.strip() != "1":
+        raise KsftSkipEx("Remote does not have auto_flowlabels enabled")
+
+
+def _ethtool_get_cfg(cfg, fl_type):
+    descr = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout
+
+    converter = {
+        "IP SA": "s",
+        "IP DA": "d",
+        "L3 proto": "t",
+        "L4 bytes 0 & 1 [TCP/UDP src port]": "f",
+        "L4 bytes 2 & 3 [TCP/UDP dst port]": "n",
+        "IPv6 Flow Label": "l",
+    }
+
+    ret = ""
+    for line in descr.split("\n")[1:-2]:
+        # if this raises we probably need to add more keys to converter above
+        ret += converter[line]
+    return ret
+
+
+def _traffic(cfg, one_sock, one_cpu):
+    local_port  = rand_port(socket.SOCK_DGRAM)
+    remote_port = rand_port(socket.SOCK_DGRAM)
+
+    sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
+    sock.bind(("", local_port))
+    sock.connect((cfg.remote_addr_v["6"], 0))
+    if one_sock:
+        send = f"exec 5<>/dev/udp/{cfg.addr_v['6']}/{local_port}; " \
+                "for i in `seq 20`; do echo a >&5; sleep 0.02; done; exec 5>&-"
+    else:
+        send = "for i in `seq 20`; do echo a | socat -t0.02 - UDP6:" \
+              f"[{cfg.addr_v['6']}]:{local_port},sourceport={remote_port}; done"
+
+    cpus = set()
+    with bkg(send, shell=True, host=cfg.remote, exit_wait=True):
+        for _ in range(20):
+            fd_read_timeout(sock.fileno(), 1)
+            cpu = sock.getsockopt(socket.SOL_SOCKET, socket.SO_INCOMING_CPU)
+            cpus.add(cpu)
+
+    if one_cpu:
+        ksft_eq(len(cpus), 1,
+                f"{one_sock=} - expected one CPU, got traffic on: {cpus=}")
+    else:
+        ksft_ge(len(cpus), 2,
+                f"{one_sock=} - expected many CPUs, got traffic on: {cpus=}")
+
+
+def test_rss_flow_label(cfg):
+    """
+    Test hashing on IPv6 flow label. Send traffic over a single socket
+    and over multiple sockets. Depend on the remote having auto-label
+    enabled so that it randomizes the label per socket.
+    """
+
+    cfg.require_ipver("6")
+    cfg.require_cmd("socat", remote=True)
+    _check_system(cfg)
+
+    # Enable flow label hashing for UDP6
+    initial = _ethtool_get_cfg(cfg, "udp6")
+    no_lbl = initial.replace("l", "")
+    if "l" not in initial:
+        try:
+            cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 l{no_lbl}")
+        except CmdExitFailure as exc:
+            raise KsftSkipEx("Device doesn't support Flow Label for UDP6") from exc
+
+        defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}")
+
+    _traffic(cfg, one_sock=True, one_cpu=True)
+    _traffic(cfg, one_sock=False, one_cpu=False)
+
+    # Disable it, we should see no hashing (reset was already defer()ed)
+    cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {no_lbl}")
+
+    _traffic(cfg, one_sock=False, one_cpu=True)
+
+
+def _check_v4_flow_types(cfg):
+    for fl_type in ["tcp4", "udp4", "ah4", "esp4", "sctp4"]:
+        try:
+            cur = cmd(f"ethtool -n {cfg.ifname} rx-flow-hash {fl_type}").stdout
+            ksft_not_in("Flow Label", cur,
+                        comment=f"{fl_type=} has Flow Label:" + cur)
+        except CmdExitFailure:
+            # Probably does not support this flow type
+            pass
+
+
+def test_rss_flow_label_6only(cfg):
+    """
+    Test interactions with IPv4 flow types. It should not be possible to set
+    IPv6 Flow Label hashing for an IPv4 flow type. The Flow Label should also
+    not appear in the IPv4 "current config".
+    """
+
+    with ksft_raises(CmdExitFailure) as cm:
+        cmd(f"ethtool -N {cfg.ifname} rx-flow-hash tcp4 sdfnl")
+    ksft_in("Invalid argument", cm.exception.cmd.stderr)
+
+    _check_v4_flow_types(cfg)
+
+    # Try to enable Flow Labels and check again, in case it leaks thru
+    initial = _ethtool_get_cfg(cfg, "udp6")
+    changed = initial.replace("l", "") if "l" in initial else initial + "l"
+
+    cmd(f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {changed}")
+    restore = defer(cmd, f"ethtool -N {cfg.ifname} rx-flow-hash udp6 {initial}")
+
+    _check_v4_flow_types(cfg)
+    restore.exec()
+    _check_v4_flow_types(cfg)
+
+
+def main() -> None:
+    with NetDrvEpEnv(__file__, nsim_test=False) as cfg:
+        ksft_run([test_rss_flow_label,
+                  test_rss_flow_label_6only],
+                 args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()