[PATCH] net: core: set skb useful vars in __bpf_tx_skb
STALE1792d
From: <hidden>
Date: 2021-10-29 01:54:40
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Tonghao Zhang <redacted>
We may use bpf_redirect to redirect the packets to other
netdevice (e.g. ifb) in ingress and egress path.
The target netdevice may check the *skb_iif, *redirected
and *from_ingress, for example, if skb_iif or redirected
is 0, ifb will drop the packets.
Fixes: a70b506efe89 ("bpf: enforce recursion limit on redirects")
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Tonghao Zhang <redacted>
---
net/core/filter.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 4bace37a6a44..2dbff0944768 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -2107,9 +2107,19 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb) return -ENETDOWN; } - skb->dev = dev; + /* The target netdevice (e.g. ifb) may use the: + * - skb_iif + * - redirected + * - from_ingress + */ + skb->skb_iif = skb->dev->ifindex; +#ifdef CONFIG_NET_CLS_ACT + skb_set_redirected(skb, skb->tc_at_ingress); +#else skb->tstamp = 0; +#endif + skb->dev = dev; dev_xmit_recursion_inc(); ret = dev_queue_xmit(skb); dev_xmit_recursion_dec();
--
2.27.0