path: root/drivers/net/netkit.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2023 Isovalent */

#include <linux/netdevice.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/filter.h>
#include <linux/netfilter_netdev.h>
#include <linux/bpf_mprog.h>
#include <linux/indirect_call_wrapper.h>

#include <net/netdev_lock.h>
#include <net/netdev_queues.h>
#include <net/netdev_rx_queue.h>
#include <net/xdp_sock_drv.h>
#include <net/netkit.h>
#include <net/dst.h>
#include <net/tcx.h>

#define NETKIT_DRV_NAME	"netkit"

#define NETKIT_NUM_RX_QUEUES_MAX  1024
#define NETKIT_NUM_TX_QUEUES_MAX  1

#define NETKIT_NUM_RX_QUEUES_REAL 1
#define NETKIT_NUM_TX_QUEUES_REAL 1

struct netkit {
	__cacheline_group_begin(netkit_fastpath);
	struct net_device __rcu *peer;
	struct bpf_mprog_entry __rcu *active;
	enum netkit_action policy;
	enum netkit_scrub scrub;
	struct bpf_mprog_bundle	bundle;
	__cacheline_group_end(netkit_fastpath);

	__cacheline_group_begin(netkit_slowpath);
	enum netkit_mode mode;
	enum netkit_pairing pair;
	bool primary;
	u32 headroom;
	__cacheline_group_end(netkit_slowpath);
};

struct netkit_link {
	struct bpf_link link;
	struct net_device *dev;
};

static struct rtnl_link_ops netkit_link_ops;

static __always_inline int
netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb,
	   enum netkit_action ret)
{
	const struct bpf_mprog_fp *fp;
	const struct bpf_prog *prog;

	bpf_mprog_foreach_prog(entry, fp, prog) {
		bpf_compute_data_pointers(skb);
		ret = bpf_prog_run(prog, skb);
		if (ret != NETKIT_NEXT)
			break;
	}
	return ret;
}

static void netkit_xnet(struct sk_buff *skb)
{
	skb->priority = 0;
	skb->mark = 0;
}

static void netkit_prep_forward(struct sk_buff *skb,
				bool xnet, bool xnet_scrub)
{
	skb_scrub_packet(skb, false);
	nf_skip_egress(skb, true);
	skb_reset_mac_header(skb);
	if (!xnet)
		return;
	skb_clear_tstamp(skb);
	if (xnet_scrub)
		netkit_xnet(skb);
}

static struct netkit *netkit_priv(const