[bpf-next,V1,4/6] bpf: make it possible to identify BPF redirected SKBs

Commit Message

Jesper Dangaard Brouer Oct. 6, 2020, 4:03 p.m. UTC

This change makes it possible to identify SKBs that have been redirected
by TC-BPF (cls_act). This is needed for a number of cases.

(1) For collaborating with driver ifb net_devices.
(2) For avoiding starting generic-XDP prog on TC ingress redirect.
(3) Next MTU check patches need ability to identify redirected SKBs.

Signed-off-by: Jesper Dangaard Brouer <[e-mail]>
---
 net/core/dev.c    |    2 ++
 net/sched/Kconfig |    1 +
 2 files changed, 3 insertions(+)

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 9d55bf5d1a65..b433098896b2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3885,6 +3885,7 @@  sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
 		return NULL;
 	case TC_ACT_REDIRECT:
 		/* No need to push/pop skb's mac_header here on egress! */
+		skb_set_redirected(skb, false);
 		skb_do_redirect(skb);
 		*ret = NET_XMIT_SUCCESS;
 		return NULL;
@@ -4974,6 +4975,7 @@  sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret,
 		 * redirecting to another netdev
 		 */
 		__skb_push(skb, skb->mac_len);
+		skb_set_redirected(skb, true);
 		skb_do_redirect(skb);
 		return NULL;
 	case TC_ACT_CONSUMED:
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index a3b37d88800e..a1bbaa8fd054 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -384,6 +384,7 @@  config NET_SCH_INGRESS
 	depends on NET_CLS_ACT
 	select NET_INGRESS
 	select NET_EGRESS
+	select NET_REDIRECT
 	help
 	  Say Y here if you want to use classifiers for incoming and/or outgoing
 	  packets. This qdisc doesn't do anything else besides running classifiers,