[PATCH net-next v2 5/6] eth: mpnic: IPv4 and IPv6 in IPv6 tunnel segmentation
From: Daniel Zahka
Date: Tue Nov 10 2026 - 17:08:38 EST
The device can fully segment 4-in-6 and 6-in-6 packet types. Add
mpnic_features_check_encap_gso() to check the skb for some additional
constraints, such as ip6 non-atomic frag ext header.
Signed-off-by: Daniel Zahka <daniel.zahka@xxxxxxxxx>
---
v2:
- derive inner L3 header length from csum_start rather than
inner_transport_header, which can be stale for DODGY skbs
- check the outer header is IPv6 in mpnic_ipxip6_gso_ok(), since
SKB_GSO_IPXIP6 can be set by a nested tunnel under an IPv4 outer
- move hw_enc_features setup to the Tx checksum offload patch
---
drivers/net/ethernet/meta/mpnic/mpnic_csr.h | 3 ++
drivers/net/ethernet/meta/mpnic/mpnic_netdev.c | 1 +
drivers/net/ethernet/meta/mpnic/mpnic_txrx.c | 53 ++++++++++++++++++++++++--
3 files changed, 53 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_csr.h b/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
index 2cd627d62bf5..63282916eb13 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_csr.h
@@ -14,6 +14,7 @@
/* Transmit Work Descriptor Format */
#define MPNIC_TWD_L2_HLEN DESC_GENMASK(5, 0)
+#define MPNIC_TWD_L3_OHLEN DESC_GENMASK(15, 8)
#define MPNIC_TWD_L3_IHLEN DESC_GENMASK(23, 16)
#define MPNIC_TWD_CSUM_OFFSET DESC_GENMASK(27, 24)
#define MPNIC_TWD_L4_HLEN DESC_GENMASK(31, 28)
@@ -30,6 +31,8 @@ enum {
enum {
MPNIC_TWD_L3_TYPE_IPV4 = 1,
MPNIC_TWD_L3_TYPE_IPV6 = 2,
+ MPNIC_TWD_L3_TYPE_V6V6 = 3,
+ MPNIC_TWD_L3_TYPE_V6V4 = 4,
};
#define MPNIC_TWD_FLAG_DEST_MAC DESC_BIT(43)
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c b/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
index bf3b459ba5be..032a5ee92a08 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_netdev.c
@@ -323,6 +323,7 @@ struct net_device *mpnic_netdev_alloc(struct mpnic_dev *mpd)
mpn->num_napi = queues;
netdev->features |=
+ NETIF_F_GSO_IPXIP6 |
NETIF_F_SG |
NETIF_F_HW_CSUM |
NETIF_F_RXCSUM |
diff --git a/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c b/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
index 2a0560b7dd19..839feb4716b6 100644
--- a/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
+++ b/drivers/net/ethernet/meta/mpnic/mpnic_txrx.c
@@ -22,6 +22,7 @@ struct mpnic_xmit_cb {
struct mpnic_tx_hdrs {
unsigned int i3len;
+ unsigned int o3len;
unsigned int l3_type;
unsigned int l4_type;
};
@@ -218,6 +219,9 @@ mpnic_tx_map(struct mpnic_ring *ring, struct sk_buff *skb, __le64 *meta)
static void mpnic_tx_fill_hdrs(struct sk_buff *skb, struct mpnic_tx_hdrs *hdrs)
{
+ unsigned int net_off = skb_network_offset(skb);
+ unsigned int inner_off;
+
if (!skb_is_gso(skb)) {
hdrs->i3len = skb_checksum_start(skb) - skb_network_header(skb);
return;
@@ -228,9 +232,17 @@ static void mpnic_tx_fill_hdrs(struct sk_buff *skb, struct mpnic_tx_hdrs *hdrs)
else
hdrs->l4_type = MPNIC_TWD_L4_TYPE_UDP;
- hdrs->i3len = skb_transport_offset(skb) - skb_network_offset(skb);
- hdrs->l3_type = ip_hdr(skb)->version == 4 ?
- MPNIC_TWD_L3_TYPE_IPV4 : MPNIC_TWD_L3_TYPE_IPV6;
+ if (!skb->encapsulation) {
+ hdrs->i3len = skb_transport_offset(skb) - net_off;
+ hdrs->l3_type = ip_hdr(skb)->version == 4 ?
+ MPNIC_TWD_L3_TYPE_IPV4 : MPNIC_TWD_L3_TYPE_IPV6;
+ } else {
+ inner_off = skb_inner_network_offset(skb);
+ hdrs->o3len = inner_off - net_off;
+ hdrs->i3len = skb_checksum_start_offset(skb) - inner_off;
+ hdrs->l3_type = inner_ip_hdr(skb)->version == 4 ?
+ MPNIC_TWD_L3_TYPE_V6V4 : MPNIC_TWD_L3_TYPE_V6V6;
+ }
}
static bool
@@ -304,6 +316,7 @@ mpnic_tx_offloads(struct mpnic_ring *ring, struct sk_buff *skb, __le64 *meta)
*meta |= cpu_to_le64(FIELD_PREP(MPNIC_TWD_L2_HLEN,
skb_mac_header_len(skb) / 2) |
FIELD_PREP(MPNIC_TWD_L3_IHLEN, hdrs.i3len / 2) |
+ FIELD_PREP(MPNIC_TWD_L3_OHLEN, hdrs.o3len / 2) |
FIELD_PREP(MPNIC_TWD_L3_TYPE, hdrs.l3_type) |
FIELD_PREP(MPNIC_TWD_L4_TYPE, hdrs.l4_type));
@@ -362,6 +375,35 @@ netdev_tx_t mpnic_xmit_frame(struct sk_buff *skb, struct net_device *dev)
return mpnic_xmit_frame_ring(skb, mpn->tx[skb_get_queue_mapping(skb)]);
}
+static bool mpnic_ipxip6_gso_ok(struct sk_buff *skb)
+{
+ struct ipv6hdr *ip6h;
+ __be16 frag_off;
+ u8 nexthdr;
+ int start;
+
+ ip6h = ipv6_hdr(skb);
+ if (ip6h->version != 6)
+ return false;
+
+ nexthdr = ip6h->nexthdr;
+ start = skb_network_offset(skb) + sizeof(*ip6h);
+ start = ipv6_skip_exthdr(skb, start, &nexthdr, &frag_off);
+
+ return !frag_off && start == skb_inner_network_offset(skb) &&
+ (nexthdr == IPPROTO_IPV6 || nexthdr == IPPROTO_IPIP);
+}
+
+static netdev_features_t
+mpnic_features_check_encap_gso(struct sk_buff *skb, netdev_features_t features)
+{
+ if (skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP6 &&
+ mpnic_ipxip6_gso_ok(skb))
+ return features;
+
+ return features & ~NETIF_F_GSO_IPXIP6;
+}
+
netdev_features_t mpnic_features_check(struct sk_buff *skb,
struct net_device *dev,
netdev_features_t features)
@@ -388,7 +430,10 @@ netdev_features_t mpnic_features_check(struct sk_buff *skb,
!FIELD_FIT(MPNIC_TWD_MSS, skb_shinfo(skb)->gso_size)))
return features & ~NETIF_F_GSO_MASK;
- return features;
+ if (!skb->encapsulation || !skb_is_gso(skb))
+ return features;
+
+ return mpnic_features_check_encap_gso(skb, features);
}
static void mpnic_clean_twq0(struct mpnic_napi_vector *nv, int napi_budget,
--
2.52.0