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Commit 6103aa96 authored by John Fastabend's avatar John Fastabend Committed by David S. Miller
Browse files

net: implement XDP_REDIRECT for xdp generic 



Add support for redirect to xdp generic creating a fall back for
devices that do not yet have support and allowing test infrastructure
using veth pairs to be built.

Signed-off-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Tested-by: default avatarAndy Gospodarek <andy@greyhouse.net>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 832622e6

include/linux/filter.h

+1 −0
Original line number Diff line number Diff line
@@ -712,6 +712,7 @@ bool bpf_helper_changes_pkt_data(void *func); 
struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,

				       const struct bpf_insn *patch, u32 len);



int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb);

int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp);



void bpf_warn_invalid_xdp_action(u32 act);

net/core/dev.c

+20 −2
Original line number Diff line number Diff line
@@ -3902,6 +3902,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, 
		__skb_push(skb, -off);



	switch (act) {

	case XDP_REDIRECT:

	case XDP_TX:

		__skb_push(skb, mac_len);

		/* fall through */
@@ -3956,14 +3957,27 @@ static int do_xdp_generic(struct sk_buff *skb) 


	if (xdp_prog) {

		u32 act = netif_receive_generic_xdp(skb, xdp_prog);

		int err;



		if (act != XDP_PASS) {

			if (act == XDP_TX)

			switch (act) {

			case XDP_REDIRECT:

				err = xdp_do_generic_redirect(skb->dev, skb);

				if (err)

					goto out_redir;

			/* fallthru to submit skb */

			case XDP_TX:

				generic_xdp_tx(skb, xdp_prog);

				break;

			}

			return XDP_DROP;

		}

	}

	return XDP_PASS;

out_redir:

	trace_xdp_exception(skb->dev, xdp_prog, XDP_REDIRECT);

	kfree_skb(skb);

	return XDP_DROP;

}



static int netif_rx_internal(struct sk_buff *skb)
@@ -3977,8 +3991,12 @@ static int netif_rx_internal(struct sk_buff *skb) 
	if (static_key_false(&generic_xdp_needed)) {

		int ret = do_xdp_generic(skb);



		/* Consider XDP consuming the packet a success from

		 * the netdev point of view we do not want to count

		 * this as an error.

		 */

		if (ret != XDP_PASS)

			return NET_RX_DROP;

			return NET_RX_SUCCESS;

	}



#ifdef CONFIG_RPS

net/core/filter.c

+26 −0
Original line number Diff line number Diff line
@@ -2437,6 +2437,32 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp) 
}

EXPORT_SYMBOL_GPL(xdp_do_redirect);



int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb)

{

	struct redirect_info *ri = this_cpu_ptr(&redirect_info);

	unsigned int len;



	dev = dev_get_by_index_rcu(dev_net(dev), ri->ifindex);

	ri->ifindex = 0;

	if (unlikely(!dev)) {

		bpf_warn_invalid_xdp_redirect(ri->ifindex);

		goto err;

	}



	if (unlikely(!(dev->flags & IFF_UP)))

		goto err;



	len = dev->mtu + dev->hard_header_len + VLAN_HLEN;

	if (skb->len > len)

		goto err;



	skb->dev = dev;

	return 0;

err:

	return -EINVAL;

}

EXPORT_SYMBOL_GPL(xdp_do_generic_redirect);



BPF_CALL_2(bpf_xdp_redirect, u32, ifindex, u64, flags)

{

	struct redirect_info *ri = this_cpu_ptr(&redirect_info);