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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/sched
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/sched')
-rw-r--r--net/sched/act_bpf.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 46f47e58b3be..54d5652cfe6c 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -12,6 +12,7 @@
#include <linux/bpf.h>
#include <net/netlink.h>
+#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
@@ -53,6 +54,8 @@ static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act,
bpf_compute_data_pointers(skb);
filter_res = BPF_PROG_RUN(filter, skb);
}
+ if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK)
+ skb_orphan(skb);
rcu_read_unlock();
/* A BPF program may overwrite the default action opcode.