Subject: [PATCH net-next v19 10/12] virtio_net: Add support for IPv6 ethtool steering

From: Daniel Jurgens <[email-masked]>
Date: Wed, 4 Feb 2026 16:39:38 -0600

Implement support for IPV6_USER_FLOW type rules.

Example:
$ ethtool -U ens9 flow-type ip6 src-ip fe80::2 dst-ip fe80::4 action 3
Added rule with ID 0

The example rule will forward packets with the specified source and
destination IP addresses to RX ring 3.

Signed-off-by: Daniel Jurgens <[email-masked]>
Reviewed-by: Parav Pandit <[email-masked]>
Reviewed-by: Shahar Shitrit <[email-masked]>
Reviewed-by: Xuan Zhuo <[email-masked]>
---
v4: commit message typo

v12:
  - refactor calculate_flow_sizes. MST
  - Move parse_ip6 l3_mask check to TCP/UDP patch. MST
  - Set eth proto to ipv6 as needed. MST
  - Also check l4_4_bytes mask is 0 in setup_ip_key_mask. MST
  - Remove tclass check in setup_ip_key_mask. If it's not suppored it
    will be caught in validate_classifier_selectors.  MST
  - Changed error return in setup_ip_key_mask to -EINVAL

v13:
  - Verify nexthdr unset for ip6. MST
  - Return -EINVAL if tclass is set. It's available in the struct.

v17:
  - Fixed portability bugs for unaligned reads and writes. MST

---
---
 drivers/net/virtio_net.c | 105 +++++++++++++++++++++++++++++++++++----
 1 file changed, 94 insertions(+), 11 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 92e34f51737c..a4e46b767553 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -5852,6 +5852,40 @@ static bool validate_ip4_mask(const struct virtnet_ff *ff,
 	return true;
 }
 
+static bool validate_ip6_mask(const struct virtnet_ff *ff,
+			      const struct virtio_net_ff_selector *sel,
+			      const struct virtio_net_ff_selector *sel_cap)
+{
+	bool partial_mask = !!(sel_cap->flags & VIRTIO_NET_FF_MASK_F_PARTIAL_MASK);
+	struct in6_addr tmp;
+	struct ipv6hdr *cap, *mask;
+
+	cap = (struct ipv6hdr *)&sel_cap->mask;
+	mask = (struct ipv6hdr *)&sel->mask;
+
+	/* mask->saddr/daddr may be unaligned; copy to aligned tmp for
+	 * ipv6_addr_any().
+	 */
+	memcpy(&tmp, &mask->saddr, sizeof(tmp));
+	if (!ipv6_addr_any(&tmp) &&
+	    !check_mask_vs_cap(&mask->saddr, &cap->saddr,
+			       sizeof(cap->saddr), partial_mask))
+		return false;
+
+	memcpy(&tmp, &mask->daddr, sizeof(tmp));
+	if (!ipv6_addr_any(&tmp) &&
+	    !check_mask_vs_cap(&mask->daddr, &cap->daddr,
+			       sizeof(cap->daddr), partial_mask))
+		return false;
+
+	if (mask->nexthdr &&
+	    !check_mask_vs_cap(&mask->nexthdr, &cap->nexthdr,
+			       sizeof(cap->nexthdr), partial_mask))
+		return false;
+
+	return true;
+}
+
 static bool validate_mask(const struct virtnet_ff *ff,
 			  const struct virtio_net_ff_selector *sel)
 {
@@ -5866,6 +5900,9 @@ static bool validate_mask(const struct virtnet_ff *ff,
 
 	case VIRTIO_NET_FF_MASK_TYPE_IPV4:
 		return validate_ip4_mask(ff, sel, sel_cap);
+
+	case VIRTIO_NET_FF_MASK_TYPE_IPV6:
+		return validate_ip6_mask(ff, sel, sel_cap);
 	}
 
 	return false;
@@ -5893,11 +5930,33 @@ static void parse_ip4(struct iphdr *mask, struct iphdr *key,
 	}
 }
 
+static void parse_ip6(struct ipv6hdr *mask, struct ipv6hdr *key,
+		      const struct ethtool_rx_flow_spec *fs)
+{
+	const struct ethtool_usrip6_spec *l3_mask = &fs->m_u.usr_ip6_spec;
+	const struct ethtool_usrip6_spec *l3_val  = &fs->h_u.usr_ip6_spec;
+
+	if (!ipv6_addr_any((struct in6_addr *)l3_mask->ip6src)) {
+		memcpy(&mask->saddr, l3_mask->ip6src, sizeof(mask->saddr));
+		memcpy(&key->saddr, l3_val->ip6src, sizeof(key->saddr));
+	}
+
+	if (!ipv6_addr_any((struct in6_addr *)l3_mask->ip6dst)) {
+		memcpy(&mask->daddr, l3_mask->ip6dst, sizeof(mask->daddr));
+		memcpy(&key->daddr, l3_val->ip6dst, sizeof(key->daddr));
+	}
+}
+
 static bool has_ipv4(u32 flow_type)
 {
 	return flow_type == IP_USER_FLOW;
 }
 
+static bool has_ipv6(u32 flow_type)
+{
+	return flow_type == IPV6_USER_FLOW;
+}
+
 static int setup_classifier(struct virtnet_ff *ff,
 			    struct virtnet_classifier **c)
 {
@@ -6034,6 +6093,7 @@ static bool supported_flow_type(const struct ethtool_rx_flow_spec *fs)
 	switch (fs->flow_type) {
 	case ETHER_FLOW:
 	case IP_USER_FLOW:
+	case IPV6_USER_FLOW:
 		return true;
 	}
 
@@ -6073,6 +6133,8 @@ static void calculate_flow_sizes(struct ethtool_rx_flow_spec *fs,
 		++(*num_hdrs);
 		if (has_ipv4(fs->flow_type))
 			size += sizeof(struct iphdr);
+		else if (has_ipv6(fs->flow_type))
+			size += sizeof(struct ipv6hdr);
 	}
 
 	BUG_ON(size > 0xff);
@@ -6100,7 +6162,10 @@ static void setup_eth_hdr_key_mask(struct virtio_net_ff_selector *selector,
 
 	if (num_hdrs > 1) {
 		eth_m->h_proto = cpu_to_be16(0xffff);
-		eth_k->h_proto = cpu_to_be16(ETH_P_IP);
+		if (has_ipv4(fs->flow_type))
+			eth_k->h_proto = cpu_to_be16(ETH_P_IP);
+		else
+			eth_k->h_proto = cpu_to_be16(ETH_P_IPV6);
 	} else {
 		memcpy(eth_m, &fs->m_u.ether_spec, sizeof(*eth_m));
 		memcpy(eth_k, &fs->h_u.ether_spec, sizeof(*eth_k));
@@ -6111,20 +6176,38 @@ static int setup_ip_key_mask(struct virtio_net_ff_selector *selector,
 			     u8 *key,
 			     const struct ethtool_rx_flow_spec *fs)
 {
+	struct ipv6hdr *v6_m = (struct ipv6hdr *)&selector->mask;
 	struct iphdr *v4_m = (struct iphdr *)&selector->mask;
+	struct ipv6hdr *v6_k = (struct ipv6hdr *)key;
 	struct iphdr *v4_k = (struct iphdr *)key;
 
-	selector->type = VIRTIO_NET_FF_MASK_TYPE_IPV4;
-	selector->length = sizeof(struct iphdr);
+	if (has_ipv6(fs->flow_type)) {
+		selector->type = VIRTIO_NET_FF_MASK_TYPE_IPV6;
+		selector->length = sizeof(struct ipv6hdr);
+
+		/* exclude tclass, it's not exposed properly struct ip6hdr */
+		if (fs->h_u.usr_ip6_spec.l4_4_bytes ||
+		    fs->m_u.usr_ip6_spec.l4_4_bytes ||
+		    fs->h_u.usr_ip6_spec.tclass ||
+		    fs->m_u.usr_ip6_spec.tclass ||
+		    fs->h_u.usr_ip6_spec.l4_proto ||
+		    fs->m_u.usr_ip6_spec.l4_proto)
+			return -EINVAL;
 
-	if (fs->h_u.usr_ip4_spec.l4_4_bytes ||
-	    fs->h_u.usr_ip4_spec.ip_ver != ETH_RX_NFC_IP4 ||
-	    fs->m_u.usr_ip4_spec.l4_4_bytes ||
-	    fs->m_u.usr_ip4_spec.ip_ver ||
-	    fs->m_u.usr_ip4_spec.proto)
-		return -EINVAL;
+		parse_ip6(v6_m, v6_k, fs);
+	} else {
+		selector->type = VIRTIO_NET_FF_MASK_TYPE_IPV4;
+		selector->length = sizeof(struct iphdr);
+
+		if (fs->h_u.usr_ip4_spec.l4_4_bytes ||
+		    fs->h_u.usr_ip4_spec.ip_ver != ETH_RX_NFC_IP4 ||
+		    fs->m_u.usr_ip4_spec.l4_4_bytes ||
+		    fs->m_u.usr_ip4_spec.ip_ver ||
+		    fs->m_u.usr_ip4_spec.proto)
+			return -EINVAL;
 
-	parse_ip4(v4_m, v4_k, fs);
+		parse_ip4(v4_m, v4_k, fs);
+	}
 
 	return 0;
 }
@@ -6194,7 +6277,7 @@ static int build_and_insert(struct virtnet_ff *ff,
 
 	setup_eth_hdr_key_mask(selector, key, fs, num_hdrs);
 
-	if (has_ipv4(fs->flow_type)) {
+	if (has_ipv4(fs->flow_type) || has_ipv6(fs->flow_type)) {
 		selector = next_selector(selector);
 
 		err = setup_ip_key_mask(selector, key + sizeof(struct ethhdr), fs);
-- 
2.50.1