On 17/10/17 - 10:26:58, Yuchung Cheng wrote:
> On Mon, Oct 16, 2017 at 11:37 PM, Christoph Paasch <cpaa...@apple.com> wrote:
> > We already allow to enable TFO without a cookie by using the
> > fastopen-sysctl and setting it to TFO_SERVER_COOKIE_NOT_REQD (0x200).
> > This is safe to do in certain environments where we know that there
> > isn't a malicous host (aka., data-centers).
> >
> > A server however might be talking to both sides (public Internet and
> > data-center). So, this server would want to enable cookie-less TFO for
> > the connections that go to the data-center while enforcing cookies for
> > the traffic from the Internet.
> >
> > This patch exposes a socket-option to enable this (protected by
> > CAP_NET_ADMIN).
> >
> > Signed-off-by: Christoph Paasch <cpaa...@apple.com>
> > ---
> > include/linux/tcp.h | 1 +
> > include/uapi/linux/tcp.h | 1 +
> > net/ipv4/tcp.c | 14 ++++++++++++++
> > net/ipv4/tcp_fastopen.c | 6 ++++--
> > 4 files changed, 20 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/tcp.h b/include/linux/tcp.h
> > index 1d2c44e09e31..cda5d4dc8d70 100644
> > --- a/include/linux/tcp.h
> > +++ b/include/linux/tcp.h
> > @@ -228,6 +228,7 @@ struct tcp_sock {
> > syn_fastopen_ch:1, /* Active TFO re-enabling probe */
> > syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
> > save_syn:1, /* Save headers of SYN packet */
> > + no_tfo_cookie:1, /* Allow send/recv SYN+data without a
> > cookie */
> can we rename to fastopen_no_cookie and move one line above so TFO
> stuff is together with similar naming.
Sure, will rename & move.
>
> > is_cwnd_limited:1;/* forward progress limited by snd_cwnd?
> > */
> > u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */
> >
> > diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
> > index 15c25eccab2b..d44f4bef056c 100644
> > --- a/include/uapi/linux/tcp.h
> > +++ b/include/uapi/linux/tcp.h
> > @@ -119,6 +119,7 @@ enum {
> > #define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */
> > #define TCP_ULP 31 /* Attach a ULP to a TCP
> > connection */
> > #define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with
> > extensions */
> > +#define TCP_NO_TFO_COOKIE 33 /* Enable TFO without a TFO cookie
> > */
> >
> > struct tcp_repair_opt {
> > __u32 opt_code;
> > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> > index 3b34850d361f..88c90be12d9f 100644
> > --- a/net/ipv4/tcp.c
> > +++ b/net/ipv4/tcp.c
> > @@ -2821,6 +2821,16 @@ static int do_tcp_setsockopt(struct sock *sk, int
> > level,
> > err = -EOPNOTSUPP;
> > }
> > break;
> > + case TCP_NO_TFO_COOKIE:
> rename to TCP_FASTOPEN_NO_COOKIE for better consistency on TFO
> options?
Yes, I will rename.
> I am also cooking a TCP_FASTOPEN_KEY option patch to allow
> listener to update the key.
I see - nice!
Thanks,
Christoph
>
> > + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
> > + err = -EPERM;
> > + else if (val > 1 || val < 0)
> > + err = -EINVAL;
> > + else if (!((1 << sk->sk_state) & (TCPF_CLOSE |
> > TCPF_LISTEN)))
> > + err = -EINVAL;
> > + else
> > + tp->no_tfo_cookie = 1;
> > + break;
> > case TCP_TIMESTAMP:
> > if (!tp->repair)
> > err = -EPERM;
> > @@ -3219,6 +3229,10 @@ static int do_tcp_getsockopt(struct sock *sk, int
> > level,
> > val = tp->fastopen_connect;
> > break;
> >
> > + case TCP_NO_TFO_COOKIE:
> > + val = tp->no_tfo_cookie;
> > + break;
> > +
> > case TCP_TIMESTAMP:
> > val = tcp_time_stamp_raw() + tp->tsoffset;
> > break;
> > diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
> > index 7ee4aadcdd71..c1b00b666b43 100644
> > --- a/net/ipv4/tcp_fastopen.c
> > +++ b/net/ipv4/tcp_fastopen.c
> > @@ -309,7 +309,8 @@ struct sock *tcp_try_fastopen(struct sock *sk, struct
> > sk_buff *skb,
> > return NULL;
> > }
> >
> > - if (syn_data && (tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD))
> > + if (syn_data && ((tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD) ||
> > + tcp_sk(sk)->no_tfo_cookie))
> > goto fastopen;
> >
> > if (foc->len >= 0 && /* Client presents or requests a cookie */
> > @@ -363,7 +364,8 @@ bool tcp_fastopen_cookie_check(struct sock *sk, u16
> > *mss,
> > return false;
> > }
> >
> > - if (sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_NO_COOKIE) {
> > + if ((sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_NO_COOKIE)
> > ||
> > + tcp_sk(sk)->no_tfo_cookie) {
> > cookie->len = -1;
> > return true;
> > }
> > --
> > 2.14.1
> >
