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[bpf-next,4/8] bpf: skb_verdict, support SK_PASS on RX BPF path

Message ID 1545334536-766-5-git-send-email-john.fastabend@gmail.com
State Accepted, archived
Delegated to: BPF Maintainers
Headers show
Series sockmap fixes/improvments for bpf-next | expand

Commit Message

John Fastabend Dec. 20, 2018, 7:35 p.m. UTC 
Add SK_PASS verdict support to SK_SKB_VERDICT programs. Now that
support for redirects exists we can implement SK_PASS as a redirect
to the same socket. This simplifies the BPF programs and avoids an
extra map lookup on RX path for simple visibility cases.

Further, reduces user (BPF programmer in this context) confusion
when their program drops skb due to lack of support.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 net/core/skmsg.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 56a99d0..8a91a46 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -669,6 +669,22 @@  static void sk_psock_verdict_apply(struct sk_psock *psock,
 	bool ingress;
 
 	switch (verdict) {
+	case __SK_PASS:
+		sk_other = psock->sk;
+		if (sock_flag(sk_other, SOCK_DEAD) ||
+		    !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
+			goto out_free;
+		}
+		if (atomic_read(&sk_other->sk_rmem_alloc) <=
+		    sk_other->sk_rcvbuf) {
+			struct tcp_skb_cb *tcp = TCP_SKB_CB(skb);
+
+			tcp->bpf.flags |= BPF_F_INGRESS;
+			skb_queue_tail(&psock->ingress_skb, skb);
+			schedule_work(&psock->work);
+			break;
+		}
+		goto out_free;
 	case __SK_REDIRECT:
 		sk_other = tcp_skb_bpf_redirect_fetch(skb);
 		if (unlikely(!sk_other))