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authorJoe Stringer <joe@wand.net.nz>2020-03-29 15:53:38 -0700
committerAlexei Starovoitov <ast@kernel.org>2020-03-30 13:45:04 -0700
commitcf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 (patch)
tree57b9db0835dacc52bcd96bea8b072af239e13ae2 /net/ipv6
parentb49e42a2dffd8d0202ddba98aa5ec23849cf5c3d (diff)
bpf: Add socket assign support
Add support for TPROXY via a new bpf helper, bpf_sk_assign(). This helper requires the BPF program to discover the socket via a call to bpf_sk*_lookup_*(), then pass this socket to the new helper. The helper takes its own reference to the socket in addition to any existing reference that may or may not currently be obtained for the duration of BPF processing. For the destination socket to receive the traffic, the traffic must be routed towards that socket via local route. The simplest example route is below, but in practice you may want to route traffic more narrowly (eg by CIDR): $ ip route add local default dev lo This patch avoids trying to introduce an extra bit into the skb->sk, as that would require more invasive changes to all code interacting with the socket to ensure that the bit is handled correctly, such as all error-handling cases along the path from the helper in BPF through to the orphan path in the input. Instead, we opt to use the destructor variable to switch on the prefetch of the socket. Signed-off-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200329225342.16317-2-joe@wand.net.nz
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_input.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 7b089d0ac8cd..e96304d8a4a7 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -285,7 +285,8 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
rcu_read_unlock();
/* Must drop socket now because of tproxy. */
- skb_orphan(skb);
+ if (!skb_sk_is_prefetched(skb))
+ skb_orphan(skb);
return skb;
err: