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Commit 8ae1aff0 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

tuntap: split out XDP logic 



This patch split out XDP logic into a single function. This make it to
be reused by XDP batching path in the following patch.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ac1f1f6c

drivers/net/tun.c

+51 −37
Original line number Diff line number Diff line
@@ -1636,14 +1636,14 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, 
}



static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf,

				       int buflen, int len, int pad, int delta)

				       int buflen, int len, int pad)

{

	struct sk_buff *skb = build_skb(buf, buflen);



	if (!skb)

		return ERR_PTR(-ENOMEM);



	skb_reserve(skb, pad - delta);

	skb_reserve(skb, pad);

	skb_put(skb, len);



	get_page(alloc_frag->page);
@@ -1652,6 +1652,39 @@ static struct sk_buff *__tun_build_skb(struct page_frag *alloc_frag, char *buf, 
	return skb;

}



static int tun_xdp_act(struct tun_struct *tun, struct bpf_prog *xdp_prog,

		       struct xdp_buff *xdp, u32 act)

{

	int err;



	switch (act) {

	case XDP_REDIRECT:

		err = xdp_do_redirect(tun->dev, xdp, xdp_prog);

		xdp_do_flush_map();

		if (err)

			return err;

		break;

	case XDP_TX:

		err = tun_xdp_tx(tun->dev, xdp);

		if (err < 0)

			return err;

		break;

	case XDP_PASS:

		break;

	default:

		bpf_warn_invalid_xdp_action(act);

		/* fall through */

	case XDP_ABORTED:

		trace_xdp_exception(tun->dev, xdp_prog, act);

		/* fall through */

	case XDP_DROP:

		this_cpu_inc(tun->pcpu_stats->rx_dropped);

		break;

	}



	return act;

}



static struct sk_buff *tun_build_skb(struct tun_struct *tun,

				     struct tun_file *tfile,

				     struct iov_iter *from,
@@ -1661,10 +1694,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, 
	struct page_frag *alloc_frag = &current->task_frag;

	struct bpf_prog *xdp_prog;

	int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

	unsigned int delta = 0;

	char *buf;

	size_t copied;

	int err, pad = TUN_RX_PAD;

	int pad = TUN_RX_PAD;

	int err = 0;



	rcu_read_lock();

	xdp_prog = rcu_dereference(tun->xdp_prog);
@@ -1690,7 +1723,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, 
	 */

	if (hdr->gso_type || !xdp_prog) {

		*skb_xdp = 1;

		return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);

		return __tun_build_skb(alloc_frag, buf, buflen, len, pad);

	}



	*skb_xdp = 0;
@@ -1698,9 +1731,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, 
	local_bh_disable();

	rcu_read_lock();

	xdp_prog = rcu_dereference(tun->xdp_prog);

	if (xdp_prog && !*skb_xdp) {

	if (xdp_prog) {

		struct xdp_buff xdp;

		void *orig_data;

		u32 act;



		xdp.data_hard_start = buf;
@@ -1708,49 +1740,31 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, 
		xdp_set_data_meta_invalid(&xdp);

		xdp.data_end = xdp.data + len;

		xdp.rxq = &tfile->xdp_rxq;

		orig_data = xdp.data;

		act = bpf_prog_run_xdp(xdp_prog, &xdp);



		switch (act) {

		case XDP_REDIRECT:

			get_page(alloc_frag->page);

			alloc_frag->offset += buflen;

			err = xdp_do_redirect(tun->dev, &xdp, xdp_prog);

			xdp_do_flush_map();

			if (err)

				goto err_redirect;

			goto out;

		case XDP_TX:

		act = bpf_prog_run_xdp(xdp_prog, &xdp);

		if (act == XDP_REDIRECT || act == XDP_TX) {

			get_page(alloc_frag->page);

			alloc_frag->offset += buflen;

			if (tun_xdp_tx(tun->dev, &xdp) < 0)

				goto err_redirect;

		}

		err = tun_xdp_act(tun, xdp_prog, &xdp, act);

		if (err < 0)

			goto err_xdp;

		if (err != XDP_PASS)

			goto out;

		case XDP_PASS:

			delta = orig_data - xdp.data;



		pad = xdp.data - xdp.data_hard_start;

		len = xdp.data_end - xdp.data;

			break;

		default:

			bpf_warn_invalid_xdp_action(act);

			/* fall through */

		case XDP_ABORTED:

			trace_xdp_exception(tun->dev, xdp_prog, act);

			/* fall through */

		case XDP_DROP:

			goto out;

		}

	}

	rcu_read_unlock();

	local_bh_enable();



	return __tun_build_skb(alloc_frag, buf, buflen, len, pad, delta);

	return __tun_build_skb(alloc_frag, buf, buflen, len, pad);



err_redirect:

err_xdp:

	put_page(alloc_frag->page);

out:

	rcu_read_unlock();

	local_bh_enable();

	this_cpu_inc(tun->pcpu_stats->rx_dropped);

	return NULL;

}