RE: [PATCH RESEND bpf 2/4] bpf, sockmap: Fix missing BPF_F_INGRESS flag when using apply_bytes

John Fastabend
2022-11-23T03:03:37Z

Pengcheng Yang wrote:
> When redirecting, we use sk_msg_to_ingress() to get the BPF_F_INGRESS
> flag from the msg->flags. If apply_bytes is used and it is larger than
> the current data being processed, sk_psock_msg_verdict() will not be
> called when sendmsg() is called again. At this time, the msg->flags is 0,
> and we lost the BPF_F_INGRESS flag.
>
> So we need to save the BPF_F_INGRESS flag in sk_psock and assign it to
> msg->flags before redirection.
>
> Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support")
> Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
> ---
> include/linux/skmsg.h | 1 +
> net/core/skmsg.c | 1 +
> net/ipv4/tcp_bpf.c | 1 +
> net/tls/tls_sw.c | 1 +
> 4 files changed, 4 insertions(+)
>
> diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
> index 48f4b64..e1d463f 100644
> --- a/include/linux/skmsg.h
> +++ b/include/linux/skmsg.h
> @@ -82,6 +82,7 @@ struct sk_psock {
> u32 apply_bytes;
> u32 cork_bytes;
> u32 eval;
> + u32 flags;
> struct sk_msg *cork;
> struct sk_psock_progs progs;
> #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
> index 188f855..ab2f8f3 100644
> --- a/net/core/skmsg.c
> +++ b/net/core/skmsg.c
> @@ -888,6 +888,7 @@ int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
> if (psock->sk_redir)
> sock_put(psock->sk_redir);
> psock->sk_redir = msg->sk_redir;
> + psock->flags = msg->flags;
> if (!psock->sk_redir) {
> ret = __SK_DROP;
> goto out;
> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
> index ef5de4f..1390d72 100644
> --- a/net/ipv4/tcp_bpf.c
> +++ b/net/ipv4/tcp_bpf.c
> @@ -323,6 +323,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
> break;
> case __SK_REDIRECT:
> sk_redir = psock->sk_redir;
> + msg->flags = psock->flags;
> sk_msg_apply_bytes(psock, tosend);
> if (!psock->apply_bytes) {
> /* Clean up before releasing the sock lock. */
^^^^^^^^^^^^^^^
In this block reposted here with the rest of the block

if (!psock->apply_bytes) {
/* Clean up before releasing the sock lock. */
eval = psock->eval;
psock->eval = __SK_NONE;
psock->sk_redir = NULL;
}

Now that we have a psock->flags we should clera that as
well right?