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>
This commit is contained in:
John Fastabend
2018-03-28 12:49:15 -07:00
committed by Daniel Borkmann
parent 22527437e0
commit 8934ce2fd0
5 changed files with 207 additions and 5 deletions

View File

@@ -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)) {