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Message-ID: <6e001d160707e1cf87870acee5adc302f8cb39b6.1747822866.git.pabeni@redhat.com>
Date: Wed, 21 May 2025 12:32:39 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: netdev@...r.kernel.org
Cc: Willem de Bruijn <willemdebruijn.kernel@...il.com>,
Jason Wang <jasowang@...hat.com>,
Andrew Lunn <andrew+netdev@...n.ch>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Eugenio Pérez <eperezma@...hat.com>
Subject: [PATCH net-next 5/8] net: implement virtio helpers to handle UDP GSO tunneling.
The virtio specification are introducing support for GSO over
UDP tunnel.
This patch brings in the needed defines and the additional
virtio hdr parsing/building helpers.
The UDP tunnel support uses additional fields in the virtio hdr,
and such fields location can change depending on other negotiated
features - specifically VIRTIO_NET_F_HASH_REPORT.
Try to be as conservative as possible with the new field validation.
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
include/linux/virtio_net.h | 177 ++++++++++++++++++++++++++++++--
include/uapi/linux/virtio_net.h | 33 ++++++
2 files changed, 202 insertions(+), 8 deletions(-)
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 02a9f4dc594d0..cf9c712a67cd4 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -47,9 +47,9 @@ static inline int virtio_net_hdr_set_proto(struct sk_buff *skb,
return 0;
}
-static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
- const struct virtio_net_hdr *hdr,
- bool little_endian)
+static inline int __virtio_net_hdr_to_skb(struct sk_buff *skb,
+ const struct virtio_net_hdr *hdr,
+ bool little_endian, u8 hdr_gso_type)
{
unsigned int nh_min_len = sizeof(struct iphdr);
unsigned int gso_type = 0;
@@ -57,8 +57,8 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
unsigned int p_off = 0;
unsigned int ip_proto;
- if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
- switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+ if (hdr_gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ switch (hdr_gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
case VIRTIO_NET_HDR_GSO_TCPV4:
gso_type = SKB_GSO_TCPV4;
ip_proto = IPPROTO_TCP;
@@ -84,7 +84,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
return -EINVAL;
}
- if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
+ if (hdr_gso_type & VIRTIO_NET_HDR_GSO_ECN)
gso_type |= SKB_GSO_TCP_ECN;
if (hdr->gso_size == 0)
@@ -122,7 +122,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
if (!protocol)
virtio_net_hdr_set_proto(skb, hdr);
- else if (!virtio_net_hdr_match_proto(protocol, hdr->gso_type))
+ else if (!virtio_net_hdr_match_proto(protocol, hdr_gso_type))
return -EINVAL;
else
skb->protocol = protocol;
@@ -153,7 +153,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
}
}
- if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+ if (hdr_gso_type != VIRTIO_NET_HDR_GSO_NONE) {
u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size);
unsigned int nh_off = p_off;
struct skb_shared_info *shinfo = skb_shinfo(skb);
@@ -199,6 +199,13 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
return 0;
}
+static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
+ const struct virtio_net_hdr *hdr,
+ bool little_endian)
+{
+ return __virtio_net_hdr_to_skb(skb, hdr, little_endian, hdr->gso_type);
+}
+
static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
struct virtio_net_hdr *hdr,
bool little_endian,
@@ -242,4 +249,158 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
return 0;
}
+static inline unsigned int virtio_l3min(bool is_ipv6)
+{
+ return is_ipv6 ? sizeof(struct ipv6hdr) : sizeof(struct iphdr);
+}
+
+static inline int virtio_net_hdr_tnl_to_skb(struct sk_buff *skb,
+ const struct virtio_net_hdr *hdr,
+ unsigned int tnl_hdr_offset,
+ bool tnl_csum_negotiated,
+ bool little_endian)
+{
+ u8 gso_tunnel_type = hdr->gso_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL;
+ unsigned int inner_nh, outer_th, inner_th;
+ unsigned int inner_l3min, outer_l3min;
+ struct virtio_net_hdr_tunnel *tnl;
+ u8 gso_inner_type;
+ bool outer_isv6;
+ int ret;
+
+ if (!gso_tunnel_type)
+ return virtio_net_hdr_to_skb(skb, hdr, little_endian);
+
+ /* Tunnel not supported/negotiated, but the hdr asks for it. */
+ if (!tnl_hdr_offset)
+ return -EINVAL;
+
+ /* Either ipv4 or ipv6. */
+ if (gso_tunnel_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4 &&
+ gso_tunnel_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6)
+ return -EINVAL;
+
+ /* No UDP fragments over UDP tunnel. */
+ gso_inner_type = hdr->gso_type & ~(VIRTIO_NET_HDR_GSO_ECN |
+ gso_tunnel_type);
+ if (!gso_inner_type || gso_inner_type == VIRTIO_NET_HDR_GSO_UDP)
+ return -EINVAL;
+
+ /* Relay on csum being present. */
+ if (!(hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM))
+ return -EINVAL;
+
+ /* Validate offsets. */
+ outer_isv6 = gso_tunnel_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6;
+ inner_l3min = virtio_l3min(gso_inner_type == VIRTIO_NET_HDR_GSO_TCPV6);
+ outer_l3min = ETH_HLEN + virtio_l3min(outer_isv6);
+
+ tnl = ((void *)hdr) + tnl_hdr_offset;
+ inner_th = __virtio16_to_cpu(little_endian, hdr->csum_start);
+ inner_nh = __virtio16_to_cpu(little_endian, tnl->inner_nh_offset);
+ outer_th = __virtio16_to_cpu(little_endian, tnl->outer_th_offset);
+ if (outer_th < outer_l3min ||
+ inner_nh < outer_th + sizeof(struct udphdr) ||
+ inner_th < inner_nh + inner_l3min)
+ return -EINVAL;
+
+ /* Let the basic parsing deal with plain GSO features. */
+ ret = __virtio_net_hdr_to_skb(skb, hdr, little_endian,
+ hdr->gso_type & ~gso_tunnel_type);
+ if (ret)
+ return ret;
+
+ skb_set_inner_protocol(skb, outer_isv6 ? htons(ETH_P_IPV6) :
+ htons(ETH_P_IP));
+ if (hdr->flags & VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM) {
+ if (!tnl_csum_negotiated)
+ return -EINVAL;
+
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ } else {
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
+ }
+
+ skb->inner_transport_header = inner_th + skb_headroom(skb);
+ skb->inner_network_header = inner_nh + skb_headroom(skb);
+ skb->inner_mac_header = inner_nh + skb_headroom(skb);
+ skb->transport_header = outer_th + skb_headroom(skb);
+ skb->encapsulation = 1;
+ return 0;
+}
+
+static inline int virtio_net_chk_data_valid(struct sk_buff *skb,
+ struct virtio_net_hdr *hdr,
+ bool tun_csum_negotiated)
+{
+ if (!(hdr->gso_type & VIRTIO_NET_HDR_GSO_UDP_TUNNEL)) {
+ if (!(hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID))
+ return 0;
+
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ if (!(hdr->flags & VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM))
+ return 0;
+
+ /* tunnel csum packets are invalid when the related
+ * feature has not been negotiated
+ */
+ if (!tun_csum_negotiated)
+ return -EINVAL;
+ skb->csum_level = 1;
+ return 0;
+ }
+
+ /* DATA_VALID is mutually exclusive with NEEDS_CSUM, and GSO
+ * over UDP tunnel requires the latter
+ */
+ if (hdr->flags & VIRTIO_NET_HDR_F_DATA_VALID)
+ return -EINVAL;
+ return 0;
+}
+
+static inline int virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb,
+ struct virtio_net_hdr *hdr,
+ unsigned int tnl_offset,
+ bool little_endian,
+ int vlan_hlen)
+{
+ struct virtio_net_hdr_tunnel *tnl;
+ unsigned int inner_nh, outer_th;
+ int tnl_gso_type;
+ int ret;
+
+ tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL |
+ SKB_GSO_UDP_TUNNEL_CSUM);
+ if (!tnl_gso_type)
+ return virtio_net_hdr_from_skb(skb, hdr, little_endian, false,
+ vlan_hlen);
+
+ /* Tunnel support not negotiated but skb ask for it. */
+ if (!tnl_offset)
+ return -EINVAL;
+
+ /* Let the basic parsing deal with plain GSO features. */
+ skb_shinfo(skb)->gso_type &= ~tnl_gso_type;
+ ret = virtio_net_hdr_from_skb(skb, hdr, little_endian, false,
+ vlan_hlen);
+ skb_shinfo(skb)->gso_type |= tnl_gso_type;
+ if (ret)
+ return ret;
+
+ if (skb->protocol == htons(ETH_P_IPV6))
+ hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6;
+ else
+ hdr->gso_type |= VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4;
+
+ if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM)
+ hdr->flags |= VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM;
+
+ tnl = ((void *)hdr) + tnl_offset;
+ inner_nh = skb->inner_network_header - skb_headroom(skb);
+ outer_th = skb->transport_header - skb_headroom(skb);
+ tnl->inner_nh_offset = __cpu_to_virtio16(little_endian, inner_nh);
+ tnl->outer_th_offset = __cpu_to_virtio16(little_endian, outer_th);
+ return 0;
+}
+
#endif /* _LINUX_VIRTIO_NET_H */
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 963540deae66a..1f1ff88a5749f 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -70,6 +70,28 @@
* with the same MAC.
*/
#define VIRTIO_NET_F_SPEED_DUPLEX 63 /* Device set linkspeed and duplex */
+#define VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO 65 /* Driver can receive
+ * GSO-over-UDP-tunnel packets
+ */
+#define VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM 66 /* Driver handles
+ * GSO-over-UDP-tunnel
+ * packets with partial csum
+ * for the outer header
+ */
+#define VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO 67 /* Device can receive
+ * GSO-over-UDP-tunnel packets
+ */
+#define VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO_CSUM 68 /* Device handles
+ * GSO-over-UDP-tunnel
+ * packets with partial csum
+ * for the outer header
+ */
+
+/* Offloads bits corresponding to VIRTIO_NET_F_HOST_UDP_TUNNEL_GSO{,_CSUM}
+ * features
+ */
+#define VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_MAPPED 46
+#define VIRTIO_NET_F_GUEST_UDP_TUNNEL_GSO_CSUM_MAPPED 47
#ifndef VIRTIO_NET_NO_LEGACY
#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
@@ -131,12 +153,17 @@ struct virtio_net_hdr_v1 {
#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */
#define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */
#define VIRTIO_NET_HDR_F_RSC_INFO 4 /* rsc info in csum_ fields */
+#define VIRTIO_NET_HDR_F_UDP_TUNNEL_CSUM 8 /* UDP tunnel requires csum offload */
__u8 flags;
#define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */
#define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */
#define VIRTIO_NET_HDR_GSO_UDP 3 /* GSO frame, IPv4 UDP (UFO) */
#define VIRTIO_NET_HDR_GSO_TCPV6 4 /* GSO frame, IPv6 TCP */
#define VIRTIO_NET_HDR_GSO_UDP_L4 5 /* GSO frame, IPv4& IPv6 UDP (USO) */
+#define VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4 0x20 /* UDP over IPv4 tunnel present */
+#define VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6 0x40 /* UDP over IPv6 tunnel present */
+#define VIRTIO_NET_HDR_GSO_UDP_TUNNEL (VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4 | \
+ VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6)
#define VIRTIO_NET_HDR_GSO_ECN 0x80 /* TCP has ECN set */
__u8 gso_type;
__virtio16 hdr_len; /* Ethernet + IP + tcp/udp hdrs */
@@ -181,6 +208,12 @@ struct virtio_net_hdr_v1_hash {
__le16 padding;
};
+/* This header after hashing information */
+struct virtio_net_hdr_tunnel {
+ __virtio16 outer_th_offset;
+ __virtio16 inner_nh_offset;
+};
+
#ifndef VIRTIO_NET_NO_LEGACY
/* This header comes first in the scatter-gather list.
* For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must
--
2.49.0
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