From f839a6c92504cff92a10f522cf686b51ff18dd35 Mon Sep 17 00:00:00 2001
From: Ido Schimmel <idosch@mellanox.com>
Date: Tue, 4 Dec 2018 08:15:11 +0000
Subject: [PATCH] net: Do not route unicast IP packets twice
Packets marked with 'offload_l3_fwd_mark' were already forwarded by a
capable device and should not be forwarded again by the kernel.
Therefore, have the kernel consume them.
The check is performed in ip{,6}_forward_finish() in order to allow the
kernel to process such packets in ip{,6}_forward() and generate required
exceptions. For example, ICMP redirects.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/ip_forward.c | 7 +++++++
net/ipv6/ip6_output.c | 7 +++++++
2 files changed, 14 insertions(+)
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c
index 32662e9e5d218..06ee4696703c0 100644
--- a/net/ipv4/ip_forward.c
+++ b/net/ipv4/ip_forward.c
@@ -69,6 +69,13 @@ static int ip_forward_finish(struct net *net, struct sock *sk, struct sk_buff *s
__IP_INC_STATS(net, IPSTATS_MIB_OUTFORWDATAGRAMS);
__IP_ADD_STATS(net, IPSTATS_MIB_OUTOCTETS, skb->len);
+#ifdef CONFIG_NET_SWITCHDEV
+ if (skb->offload_l3_fwd_mark) {
+ consume_skb(skb);
+ return 0;
+ }
+#endif
+
if (unlikely(opt->optlen))
ip_forward_options(skb);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index ec8c235ea891a..6592a39e5ec10 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -378,6 +378,13 @@ static inline int ip6_forward_finish(struct net *net, struct sock *sk,
__IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
__IP6_ADD_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTOCTETS, skb->len);
+#ifdef CONFIG_NET_SWITCHDEV
+ if (skb->offload_l3_fwd_mark) {
+ consume_skb(skb);
+ return 0;
+ }
+#endif
+
return dst_output(net, sk, skb);
}
--
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