bpf: sockmap redirect ingress support
Add support for the BPF_F_INGRESS flag in sk_msg redirect helper.
To do this add a scatterlist ring for receiving socks to check
before calling into regular recvmsg call path. Additionally, because
the poll wakeup logic only checked the skb recv queue we need to
add a hook in TCP stack (similar to write side) so that we have
a way to wake up polling socks when a scatterlist is redirected
to that sock.
After this all that is needed is for the redirect helper to
push the scatterlist into the psock receive queue.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 0c31be3..bccc4c2 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -485,6 +485,14 @@ static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
}
}
+static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
+ int target, struct sock *sk)
+{
+ return (tp->rcv_nxt - tp->copied_seq >= target) ||
+ (sk->sk_prot->stream_memory_read ?
+ sk->sk_prot->stream_memory_read(sk) : false);
+}
+
/*
* Wait for a TCP event.
*
@@ -554,7 +562,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
tp->urg_data)
target++;
- if (tp->rcv_nxt - tp->copied_seq >= target)
+ if (tcp_stream_is_readable(tp, target, sk))
mask |= EPOLLIN | EPOLLRDNORM;
if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {