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Commit a29ae44c authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tun-allow-to-attach-eBPF-filter' 



Jason Wang says:

====================
tun: allow to attach eBPF filter

This series tries to implement eBPF socket filter for tun. This could
be used for implementing efficient virtio-net receive filter for
vhost-net.

Changes from V2:
- fix typo
- remove unnecessary double check
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents ca46abd6 aff3d70a

drivers/net/tun.c

+50 −20
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ struct tun_flow_entry { 


#define TUN_NUM_FLOW_ENTRIES 1024



struct tun_steering_prog {

struct tun_prog {

	struct rcu_head rcu;

	struct bpf_prog *prog;

};
@@ -238,7 +238,13 @@ struct tun_struct { 
	u32 rx_batched;

	struct tun_pcpu_stats __percpu *pcpu_stats;

	struct bpf_prog __rcu *xdp_prog;

	struct tun_steering_prog __rcu *steering_prog;

	struct tun_prog __rcu *steering_prog;

	struct tun_prog __rcu *filter_prog;

};



struct veth {

	__be16 h_vlan_proto;

	__be16 h_vlan_TCI;

};



bool tun_is_xdp_buff(void *ptr)
@@ -590,7 +596,7 @@ static u16 tun_automq_select_queue(struct tun_struct *tun, struct sk_buff *skb) 


static u16 tun_ebpf_select_queue(struct tun_struct *tun, struct sk_buff *skb)

{

	struct tun_steering_prog *prog;

	struct tun_prog *prog;

	u16 ret = 0;



	prog = rcu_dereference(tun->steering_prog);
@@ -1036,12 +1042,25 @@ static void tun_automq_xmit(struct tun_struct *tun, struct sk_buff *skb) 
#endif

}



static unsigned int run_ebpf_filter(struct tun_struct *tun,

				    struct sk_buff *skb,

				    int len)

{

	struct tun_prog *prog = rcu_dereference(tun->filter_prog);



	if (prog)

		len = bpf_prog_run_clear_cb(prog->prog, skb);



	return len;

}



/* Net device start xmit */

static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)

{

	struct tun_struct *tun = netdev_priv(dev);

	int txq = skb->queue_mapping;

	struct tun_file *tfile;

	int len = skb->len;



	rcu_read_lock();

	tfile = rcu_dereference(tun->tfiles[txq]);
@@ -1067,6 +1086,15 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev) 
	    sk_filter(tfile->socket.sk, skb))

		goto drop;



	len = run_ebpf_filter(tun, skb, len);



	/* Trim extra bytes since we may insert vlan proto & TCI

	 * in tun_put_user().

	 */

	len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0;

	if (len <= 0 || pskb_trim(skb, len))

		goto drop;



	if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC)))

		goto drop;
@@ -2054,10 +2082,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, 


	if (vlan_hlen) {

		int ret;

		struct {

			__be16 h_vlan_proto;

			__be16 h_vlan_TCI;

		} veth;

		struct veth veth;



		veth.h_vlan_proto = skb->vlan_proto;

		veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
@@ -2184,19 +2209,18 @@ static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 
	return ret;

}



static void tun_steering_prog_free(struct rcu_head *rcu)

static void tun_prog_free(struct rcu_head *rcu)

{

	struct tun_steering_prog *prog = container_of(rcu,

					 struct tun_steering_prog, rcu);

	struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);



	bpf_prog_destroy(prog->prog);

	kfree(prog);

}



static int __tun_set_steering_ebpf(struct tun_struct *tun,

static int __tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,

			  struct bpf_prog *prog)

{

	struct tun_steering_prog *old, *new = NULL;

	struct tun_prog *old, *new = NULL;



	if (prog) {

		new = kmalloc(sizeof(*new), GFP_KERNEL);
@@ -2206,13 +2230,13 @@ static int __tun_set_steering_ebpf(struct tun_struct *tun, 
	}



	spin_lock_bh(&tun->lock);

	old = rcu_dereference_protected(tun->steering_prog,

	old = rcu_dereference_protected(*prog_p,

					lockdep_is_held(&tun->lock));

	rcu_assign_pointer(tun->steering_prog, new);

	rcu_assign_pointer(*prog_p, new);

	spin_unlock_bh(&tun->lock);



	if (old)

		call_rcu(&old->rcu, tun_steering_prog_free);

		call_rcu(&old->rcu, tun_prog_free);



	return 0;

}
@@ -2225,7 +2249,8 @@ static void tun_free_netdev(struct net_device *dev) 
	free_percpu(tun->pcpu_stats);

	tun_flow_uninit(tun);

	security_tun_dev_free_security(tun->security);

	__tun_set_steering_ebpf(tun, NULL);

	__tun_set_ebpf(tun, &tun->steering_prog, NULL);

	__tun_set_ebpf(tun, &tun->filter_prog, NULL);

}



static void tun_setup(struct net_device *dev)
@@ -2720,7 +2745,8 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) 
	return ret;

}



static int tun_set_steering_ebpf(struct tun_struct *tun, void __user *data)

static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,

			void __user *data)

{

	struct bpf_prog *prog;

	int fd;
@@ -2736,7 +2762,7 @@ static int tun_set_steering_ebpf(struct tun_struct *tun, void __user *data) 
			return PTR_ERR(prog);

	}



	return __tun_set_steering_ebpf(tun, prog);

	return __tun_set_ebpf(tun, prog_p, prog);

}



static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
@@ -3016,7 +3042,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd, 
		break;



	case TUNSETSTEERINGEBPF:

		ret = tun_set_steering_ebpf(tun, argp);

		ret = tun_set_ebpf(tun, &tun->steering_prog, argp);

		break;



	case TUNSETFILTEREBPF:

		ret = tun_set_ebpf(tun, &tun->filter_prog, argp);

		break;



	default:

include/uapi/linux/if_tun.h

+1 −0
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#define TUNSETVNETBE _IOW('T', 222, int)

#define TUNGETVNETBE _IOR('T', 223, int)

#define TUNSETSTEERINGEBPF _IOR('T', 224, int)

#define TUNSETFILTEREBPF _IOR('T', 225, int)



/* TUNSETIFF ifr flags */

#define IFF_TUN		0x0001