On Tue, Mar 2, 2021 at 10:37 PM Yonghong Song <yhs@xxxxxx> wrote:
>
>
>
> On 3/1/21 6:37 PM, Cong Wang wrote:
> > From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
> >
> > Now UDP supports sockmap and redirection, we can safely update
> > the sock type checks for it accordingly.
> >
> > Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> > Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
> > Cc: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> > Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
> > ---
> > net/core/sock_map.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> > index 13d2af5bb81c..f7eee4b7b994 100644
> > --- a/net/core/sock_map.c
> > +++ b/net/core/sock_map.c
> > @@ -549,7 +549,10 @@ static bool sk_is_udp(const struct sock *sk)
> >
> > static bool sock_map_redirect_allowed(const struct sock *sk)
> > {
> > - return sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN;
> > + if (sk_is_tcp(sk))
> > + return sk->sk_state != TCP_LISTEN;
> > + else
> > + return sk->sk_state == TCP_ESTABLISHED;
>
> Not a networking expert, a dump question. Here we tested
> whether sk_is_tcp(sk) or not, if not we compare
> sk->sk_state == TCP_ESTABLISHED, could this be
> always false? Mostly I missed something, some comments
> here will be good.
No, dgram sockets also use TCP_ESTABLISHED as a valid
state. I know its name looks confusing, but it is already widely
used in networking:
net/appletalk/ddp.c: sk->sk_state = TCP_ESTABLISHED;
net/appletalk/ddp.c: if (sk->sk_state != TCP_ESTABLISHED)
net/appletalk/ddp.c: if (sk->sk_state != TCP_ESTABLISHED)
net/ax25/af_ax25.c: sk->sk_state = TCP_ESTABLISHED;
net/ax25/af_ax25.c: case TCP_ESTABLISHED: /* connection
established */
net/ax25/af_ax25.c: if (sk->sk_state == TCP_ESTABLISHED &&
sk->sk_type == SOCK_SEQPACKET) {
net/ax25/af_ax25.c: sk->sk_state = TCP_ESTABLISHED;
net/ax25/af_ax25.c: if (sk->sk_state != TCP_ESTABLISHED && (flags
& O_NONBLOCK)) {
net/ax25/af_ax25.c: if (sk->sk_state != TCP_ESTABLISHED) {
net/ax25/af_ax25.c: if (sk->sk_state != TCP_ESTABLISHED) {
net/ax25/af_ax25.c: if (sk->sk_state != TCP_ESTABLISHED) {
net/ax25/af_ax25.c: if (sk->sk_state != TCP_ESTABLISHED) {
net/ax25/af_ax25.c: if (sk->sk_type == SOCK_SEQPACKET &&
sk->sk_state != TCP_ESTABLISHED) {
net/ax25/ax25_ds_in.c: ax25->sk->sk_state = TCP_ESTABLISHED;
net/ax25/ax25_in.c: make->sk_state = TCP_ESTABLISHED;
net/ax25/ax25_std_in.c: ax25->sk->sk_state =
TCP_ESTABLISHED;
net/caif/caif_socket.c: CAIF_CONNECTED = TCP_ESTABLISHED,
net/ceph/messenger.c: case TCP_ESTABLISHED:
net/ceph/messenger.c: dout("%s TCP_ESTABLISHED\n", __func__);
net/core/datagram.c: !(sk->sk_state == TCP_ESTABLISHED ||
sk->sk_state == TCP_LISTEN))
...
Hence, I believe it is okay to use it as it is, otherwise we would need
to comment on every use of it. ;)
Thanks.
