Subject: [PATCH net-next v5 10/12] virtio_net: Add support for IPv6 ethtool steering

From: Daniel Jurgens <[email-masked]>
Date: Thu, 16 Oct 2025 00:00:53 -0500

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]>
---
v4: commit message typo
---
 drivers/net/virtio_net.c | 89 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 81 insertions(+), 8 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a67060405421..f13141e9f2de 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -6912,6 +6912,34 @@ 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 ipv6hdr *cap, *mask;
+
+	cap = (struct ipv6hdr *)&sel_cap->mask;
+	mask = (struct ipv6hdr *)&sel->mask;
+
+	if (!ipv6_addr_any(&mask->saddr) &&
+	    !check_mask_vs_cap(&mask->saddr, &cap->saddr,
+			       sizeof(cap->saddr), partial_mask))
+		return false;
+
+	if (!ipv6_addr_any(&mask->daddr) &&
+	    !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)
 {
@@ -6926,6 +6954,9 @@ 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;
@@ -6948,11 +6979,38 @@ 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));
+	}
+
+	if (l3_mask->l4_proto) {
+		mask->nexthdr = l3_mask->l4_proto;
+		key->nexthdr = l3_val->l4_proto;
+	}
+}
+
 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)
 {
@@ -7088,6 +7146,7 @@ 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;
 	}
 
@@ -7130,7 +7189,8 @@ 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);
 done:
 	*key_size = size;
 	/*
@@ -7167,18 +7227,31 @@ 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);
 
-	if (fs->h_u.usr_ip4_spec.l4_4_bytes ||
-	    fs->h_u.usr_ip4_spec.tos ||
-	    fs->h_u.usr_ip4_spec.ip_ver != ETH_RX_NFC_IP4)
-		return -EOPNOTSUPP;
+		if (fs->h_u.usr_ip6_spec.l4_4_bytes ||
+		    fs->h_u.usr_ip6_spec.tclass)
+			return -EOPNOTSUPP;
 
-	parse_ip4(v4_m, v4_k, fs);
+		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.tos ||
+		    fs->h_u.usr_ip4_spec.ip_ver != ETH_RX_NFC_IP4)
+			return -EOPNOTSUPP;
+
+		parse_ip4(v4_m, v4_k, fs);
+	}
 
 	return 0;
 }
-- 
2.50.1