When probing a virtnet device, attempt to read the flow filter
capabilities. In order to use the feature the caps must also
be set. For now setting what was read is sufficient.

Signed-off-by: Daniel Jurgens <redacted>
Reviewed-by: Parav Pandit <redacted>
Reviewed-by: Shahar Shitrit <redacted>
---
v4:
    - Validate the length in the selector caps
    - Removed __free usage.
    - Removed for(int.
v5:
    - Remove unneed () after MAX_SEL_LEN macro (test bot)
v6:
    - Fix sparse warning "array of flexible structures" Jakub K/Simon H
    - Use new variable and validate ff_mask_size before set_cap. MST
---
 drivers/net/virtio_net.c           | 171 +++++++++++++++++++++++++++++
 include/linux/virtio_admin.h       |   1 +
 include/uapi/linux/virtio_net_ff.h |  91 +++++++++++++++
 3 files changed, 263 insertions(+)
 create mode 100644 include/uapi/linux/virtio_net_ff.h

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a757cbcab87f..a9fde879fdbf 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -26,6 +26,9 @@
 #include <net/netdev_rx_queue.h>
 #include <net/netdev_queues.h>
 #include <net/xdp_sock_drv.h>
+#include <linux/virtio_admin.h>
+#include <net/ipv6.h>
+#include <net/ip.h>
 
 static int napi_weight = NAPI_POLL_WEIGHT;
 module_param(napi_weight, int, 0444);

@@ -281,6 +284,14 @@ static const struct virtnet_stat_desc virtnet_stats_tx_speed_desc_qstat[] = {
 	VIRTNET_STATS_DESC_TX_QSTAT(speed, ratelimit_packets, hw_drop_ratelimits),
 };
 
+struct virtnet_ff {
+	struct virtio_device *vdev;
+	bool ff_supported;
+	struct virtio_net_ff_cap_data *ff_caps;
+	struct virtio_net_ff_cap_mask_data *ff_mask;
+	struct virtio_net_ff_actions *ff_actions;
+};
+
 #define VIRTNET_Q_TYPE_RX 0
 #define VIRTNET_Q_TYPE_TX 1
 #define VIRTNET_Q_TYPE_CQ 2

@@ -493,6 +504,8 @@ struct virtnet_info {
 	struct failover *failover;
 
 	u64 device_stats_cap;
+
+	struct virtnet_ff ff;
 };
 
 struct padded_vnet_hdr {

@@ -6753,6 +6766,160 @@ static const struct xdp_metadata_ops virtnet_xdp_metadata_ops = {
 	.xmo_rx_hash			= virtnet_xdp_rx_hash,
 };
 
+static size_t get_mask_size(u16 type)
+{
+	switch (type) {
+	case VIRTIO_NET_FF_MASK_TYPE_ETH:
+		return sizeof(struct ethhdr);
+	case VIRTIO_NET_FF_MASK_TYPE_IPV4:
+		return sizeof(struct iphdr);
+	case VIRTIO_NET_FF_MASK_TYPE_IPV6:
+		return sizeof(struct ipv6hdr);
+	case VIRTIO_NET_FF_MASK_TYPE_TCP:
+		return sizeof(struct tcphdr);
+	case VIRTIO_NET_FF_MASK_TYPE_UDP:
+		return sizeof(struct udphdr);
+	}
+
+	return 0;
+}
+
+#define MAX_SEL_LEN (sizeof(struct ipv6hdr))
+
+static void virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev)
+{
+	size_t ff_mask_size = sizeof(struct virtio_net_ff_cap_mask_data) +
+			      sizeof(struct virtio_net_ff_selector) *
+			      VIRTIO_NET_FF_MASK_TYPE_MAX;
+	struct virtio_admin_cmd_query_cap_id_result *cap_id_list;
+	struct virtio_net_ff_selector *sel;
+	size_t real_ff_mask_size;
+	int err;
+	int i;
+
+	cap_id_list = kzalloc(sizeof(*cap_id_list), GFP_KERNEL);
+	if (!cap_id_list)
+		return;
+
+	err = virtio_admin_cap_id_list_query(vdev, cap_id_list);
+	if (err)
+		goto err_cap_list;
+
+	if (!(VIRTIO_CAP_IN_LIST(cap_id_list,
+				 VIRTIO_NET_FF_RESOURCE_CAP) &&
+	      VIRTIO_CAP_IN_LIST(cap_id_list,
+				 VIRTIO_NET_FF_SELECTOR_CAP) &&
+	      VIRTIO_CAP_IN_LIST(cap_id_list,
+				 VIRTIO_NET_FF_ACTION_CAP)))
+		goto err_cap_list;
+
+	ff->ff_caps = kzalloc(sizeof(*ff->ff_caps), GFP_KERNEL);
+	if (!ff->ff_caps)
+		goto err_cap_list;
+
+	err = virtio_admin_cap_get(vdev,
+				   VIRTIO_NET_FF_RESOURCE_CAP,
+				   ff->ff_caps,
+				   sizeof(*ff->ff_caps));
+
+	if (err)
+		goto err_ff;
+
+	/* VIRTIO_NET_FF_MASK_TYPE start at 1 */
+	for (i = 1; i <= VIRTIO_NET_FF_MASK_TYPE_MAX; i++)
+		ff_mask_size += get_mask_size(i);
+
+	ff->ff_mask = kzalloc(ff_mask_size, GFP_KERNEL);
+	if (!ff->ff_mask)
+		goto err_ff;
+
+	err = virtio_admin_cap_get(vdev,
+				   VIRTIO_NET_FF_SELECTOR_CAP,
+				   ff->ff_mask,
+				   ff_mask_size);
+
+	if (err)
+		goto err_ff_mask;
+
+	ff->ff_actions = kzalloc(sizeof(*ff->ff_actions) +
+					VIRTIO_NET_FF_ACTION_MAX,
+					GFP_KERNEL);
+	if (!ff->ff_actions)
+		goto err_ff_mask;
+
+	err = virtio_admin_cap_get(vdev,
+				   VIRTIO_NET_FF_ACTION_CAP,
+				   ff->ff_actions,
+				   sizeof(*ff->ff_actions) + VIRTIO_NET_FF_ACTION_MAX);
+
+	if (err)
+		goto err_ff_action;
+
+	err = virtio_admin_cap_set(vdev,
+				   VIRTIO_NET_FF_RESOURCE_CAP,
+				   ff->ff_caps,
+				   sizeof(*ff->ff_caps));
+	if (err)
+		goto err_ff_action;
+
+	real_ff_mask_size = sizeof(struct virtio_net_ff_cap_mask_data);
+	sel = (void *)&ff->ff_mask->selectors[0];
+
+	for (i = 0; i < ff->ff_mask->count; i++) {
+		if (sel->length > MAX_SEL_LEN) {
+			err = -EINVAL;
+			goto err_ff_action;
+		}
+		real_ff_mask_size += sizeof(struct virtio_net_ff_selector) + sel->length;
+		sel = (void *)sel + sizeof(*sel) + sel->length;
+	}
+
+	if (real_ff_mask_size > ff_mask_size) {
+		err = -EINVAL;
+		goto err_ff_action;
+	}
+
+	err = virtio_admin_cap_set(vdev,
+				   VIRTIO_NET_FF_SELECTOR_CAP,
+				   ff->ff_mask,
+				   ff_mask_size);
+	if (err)
+		goto err_ff_action;
+
+	err = virtio_admin_cap_set(vdev,
+				   VIRTIO_NET_FF_ACTION_CAP,
+				   ff->ff_actions,
+				   sizeof(*ff->ff_actions) + VIRTIO_NET_FF_ACTION_MAX);
+	if (err)
+		goto err_ff_action;
+
+	ff->vdev = vdev;
+	ff->ff_supported = true;
+
+	kfree(cap_id_list);
+
+	return;
+
+err_ff_action:
+	kfree(ff->ff_actions);
+err_ff_mask:
+	kfree(ff->ff_mask);
+err_ff:
+	kfree(ff->ff_caps);
+err_cap_list:
+	kfree(cap_id_list);