On Thu, Jan 16, 2025 at 10:05 PM +08, Jiayuan Chen wrote:
> Currently, only TCP supports strparser, but sockmap doesn't intercept
> non-TCP to attach strparser. For example, with UDP, although the
> read/write handlers are replaced, strparser is not executed due to the
> lack of read_sock operation.
>
> Furthermore, in udp_bpf_recvmsg(), it checks whether psock has data, and
> if not, it falls back to the native UDP read interface, making
> UDP + strparser appear to read correctly. According to it's commit
> history, the behavior is unexpected.
>
> Moreover, since UDP lacks the concept of streams, we intercept it
> directly. Later, we will try to support Unix streams and add more
> check.
>
> Signed-off-by: Jiayuan Chen <mrpre@xxxxxxx>
> ---
Needs a Fixes: tag.
> net/core/sock_map.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> index f1b9b3958792..c6ee2d1d9cf2 100644
> --- a/net/core/sock_map.c
> +++ b/net/core/sock_map.c
> @@ -214,6 +214,14 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
> return psock;
> }
>
> +static bool sock_map_sk_strp_allowed(const struct sock *sk)
> +{
> + /* todo: support unix stream socket */
> + if (sk_is_tcp(sk))
> + return true;
> + return false;
> +}
> +
We don't need this yet, so please don't add it. Especially since this is
fix. It should be kept down to a minimum. Do the sk_is_tcp() check
directly from sock_map_link().
> static int sock_map_link(struct bpf_map *map, struct sock *sk)
> {
> struct sk_psock_progs *progs = sock_map_progs(map);
> @@ -303,7 +311,10 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
>
> write_lock_bh(&sk->sk_callback_lock);
> if (stream_parser && stream_verdict && !psock->saved_data_ready) {
> - ret = sk_psock_init_strp(sk, psock);
> + if (sock_map_sk_strp_allowed(sk))
> + ret = sk_psock_init_strp(sk, psock);
> + else
> + ret = -EOPNOTSUPP;
> if (ret) {
> write_unlock_bh(&sk->sk_callback_lock);
> sk_psock_put(sk, psock);
