[RFC PATCH mptcp-next v6 0/9] mptcp: Fast Open Mechanism

[RFC PATCH mptcp-next v6 0/9] mptcp: Fast Open Mechanism

[Dmytro Shytyi]

[PATCH v6] includes "client-server" partial support for:
1. MPTCP cookie request from client (seems OK).
2. MPTCP cookie offering from server (seems OK).
3. MPTCP SYN+DATA+COOKIE from client (seems OK).
4. subsequent write + read on the opened socket (seems OK).

===Changes between v4 and v6
- All data sent by the initiator received by listener in userspace.
- No more infinite re-transmissions of the same packet in the
end of the second connection.
- ”WARNING in sk stream kill queues”, when skb is added to
msk queue - is fixed.
- Fix the second (discarded) packet that is re-transmitted in the
end of 2nd session.
- We have (in the v4 it is not present) the FIN in the end of the
2nd (TFO data+cookie+syn) session.
- All comments from the mailing list are implemented.
- Properly remove the TS from TCP options.

===Pros/Cons of v6:
- NO modifications of existing TCP code in linux kernel.
- Increased size of the patch.
===Future work:
-Adress the appearance of "MPTCP FIN" as duplicated acks.

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>

Dmytro Shytyi (9):
  Add separate fastopen.c file.
  Initiator: MSG_FASTOPEN sendto(). request cookie
  rfree(), rmem_uncharge() prototypes to protocol.h
  Initiator: add locks() to mptcp_sendmsg_fastopen.
  Fix unxpctd val of subflow->map_seq(dscrd packet)
  mptfo variables for msk, options. Fix loop retrans
  Listener: Add received skb to msk
  mptcp_fastopen_add_skb() helpers (skb to msk)
  selftests: mptfo initiator/listener

 net/mptcp/Makefile                            |   2 +-
 net/mptcp/fastopen.c                          | 553 ++++++++++++++++++
 net/mptcp/options.c                           |   3 +
 net/mptcp/protocol.c                          |  12 +-
 net/mptcp/protocol.h                          |  63 +-
 net/mptcp/sockopt.c                           |   3 +
 net/mptcp/subflow.c                           |   8 +-
 tools/testing/selftests/net/mptcp/mptfo.sh    |  13 +
 .../selftests/net/mptcp/mptfo_initiator.c     |  41 ++
 .../selftests/net/mptcp/mptfo_listener.c      |  98 ++++
 10 files changed, 785 insertions(+), 11 deletions(-)
 create mode 100644 net/mptcp/fastopen.c
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo.sh
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo_initiator.c
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo_listener.c

-- 
2.25.1

[RFC PATCH mptcp-next v6 1/9] Add separate fastopen.c file.

[Dmytro Shytyi]

Add separate *.c file. Function prototypes are coming to protocol.h
(Suggestion of @palbeni (JUN 17))

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/Makefile   | 2 +-
 net/mptcp/fastopen.c | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 net/mptcp/fastopen.c

diff --git a/net/mptcp/Makefile b/net/mptcp/Makefile
index 8a7f68efa35f..c42ad8609876 100644
--- a/net/mptcp/Makefile
+++ b/net/mptcp/Makefile
@@ -2,7 +2,7 @@
 obj-$(CONFIG_MPTCP) += mptcp.o
 
 mptcp-y := protocol.o subflow.o options.o token.o crypto.o ctrl.o pm.o diag.o \
-	   mib.o pm_netlink.o sockopt.o pm_userspace.o sched.o
+	   mib.o pm_netlink.o sockopt.o pm_userspace.o sched.o fastopen.o
 
 obj-$(CONFIG_SYN_COOKIES) += syncookies.o
 obj-$(CONFIG_INET_MPTCP_DIAG) += mptcp_diag.o
diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
new file mode 100644
index 000000000000..0c9ef6f5d528
--- /dev/null
+++ b/net/mptcp/fastopen.c
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0
+ * MPTCP Fast Open Mechanism. Copyright (c) 2021-2022, Dmytro SHYTYI
+ */
+
+#include "protocol.h"
-- 
2.25.1

[RFC PATCH mptcp-next v6 2/9] Initiator: MSG_FASTOPEN sendto(). request cookie

[Dmytro Shytyi]

Initiator: MSG_FASTOPEN in sendto triggers the mptcp_sendsmg_fastopen.
It requests a MPTFO cookie. 
Suggestion @palbeni(JAN 17): 'split the patch in several small one'.

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/fastopen.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.c |  4 ++--
 net/mptcp/protocol.h |  6 ++++++
 3 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 0c9ef6f5d528..9974508e0f4c 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -3,3 +3,53 @@
  */
 
 #include "protocol.h"
+
+int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
+			   size_t len, struct mptcp_sock *msk,
+			   size_t *copied)
+{
+	const struct iphdr *iph;
+	struct ubuf_info *uarg;
+	struct sockaddr *uaddr;
+	struct sk_buff *skb;
+	struct tcp_sock *tp;
+	struct socket *ssk;
+	int ret;
+
+	ssk = __mptcp_nmpc_socket(msk);
+	if (unlikely(!ssk))
+		goto out_EFAULT;
+	skb = tcp_stream_alloc_skb(ssk->sk, 0, ssk->sk->sk_allocation, true);
+	if (unlikely(!skb))
+		goto out_EFAULT;
+	iph = ip_hdr(skb);
+	if (unlikely(!iph))
+		goto out_EFAULT;
+	uarg = msg_zerocopy_realloc(sk, len, skb_zcopy(skb));
+	if (unlikely(!uarg))
+		goto out_EFAULT;
+	uaddr = msg->msg_name;
+
+	tp = tcp_sk(ssk->sk);
+	if (unlikely(!tp))
+		goto out_EFAULT;
+	if (!tp->fastopen_req)
+		tp->fastopen_req = kzalloc(sizeof(*tp->fastopen_req),
+					   ssk->sk->sk_allocation);
+
+	if (unlikely(!tp->fastopen_req))
+		goto out_EFAULT;
+	tp->fastopen_req->data = msg;
+	tp->fastopen_req->size = len;
+	tp->fastopen_req->uarg = uarg;
+
+	/* requests a cookie */
+	ret = mptcp_stream_connect(sk->sk_socket, uaddr,
+				   msg->msg_namelen, msg->msg_flags);
+	if (!ret)
+		*copied = len;
+	return ret;
+out_EFAULT:
+	ret = -EFAULT;
+	return ret;
+}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 55442df8fb97..6bbf1b86465d 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1672,9 +1672,9 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int ret = 0;
 	long timeo;
 
-	/* we don't support FASTOPEN yet */
+	/* we don't fully support FASTOPEN yet */
 	if (msg->msg_flags & MSG_FASTOPEN)
-		return -EOPNOTSUPP;
+		ret = mptcp_sendmsg_fastopen(sk, msg, len, msk, &copied);
 
 	/* silently ignore everything else */
 	msg->msg_flags &= MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 1bc9f6e77ddd..ad51910f1cc9 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -836,6 +836,12 @@ void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_
 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
 
+// Fast Open Mechanism functions begin
+int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
+			   size_t len, struct mptcp_sock *msk,
+			   size_t *copied);
+// Fast Open Mechanism functions end
+
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
 {
 	return READ_ONCE(msk->pm.addr_signal) &
-- 
2.25.1

[RFC PATCH mptcp-next v6 3/9] rfree(), rmem_uncharge() prototypes to protocol.h

[Dmytro Shytyi]

These 2 functions required the mptcp_fastopen_add_skb() that is not in
protocol.c. Thus we export them to *.h and reuse in fastopen.c

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/protocol.c | 4 ++--
 net/mptcp/protocol.h | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 6bbf1b86465d..ba50aa88d5d8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -178,7 +178,7 @@ static void __mptcp_rmem_reclaim(struct sock *sk, int amount)
 	__sk_mem_reduce_allocated(sk, amount);
 }
 
-static void mptcp_rmem_uncharge(struct sock *sk, int size)
+void mptcp_rmem_uncharge(struct sock *sk, int size)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	int reclaimable;
@@ -191,7 +191,7 @@ static void mptcp_rmem_uncharge(struct sock *sk, int size)
 		__mptcp_rmem_reclaim(sk, reclaimable);
 }
 
-static void mptcp_rfree(struct sk_buff *skb)
+void mptcp_rfree(struct sk_buff *skb)
 {
 	unsigned int len = skb->truesize;
 	struct sock *sk = skb->sk;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index ad51910f1cc9..5cd14eacd1d6 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -835,6 +835,9 @@ void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
 void mptcp_event_addr_announced(const struct sock *ssk, const struct mptcp_addr_info *info);
 void mptcp_event_addr_removed(const struct mptcp_sock *msk, u8 id);
 bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
+int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags);
+void mptcp_rmem_uncharge(struct sock *sk, int size);
+void mptcp_rfree(struct sk_buff *skb);
 
 // Fast Open Mechanism functions begin
 int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
-- 
2.25.1

[RFC PATCH mptcp-next v6 4/9] Initiator: add locks() to mptcp_sendmsg_fastopen.

[Dmytro Shytyi]

Suggestion of @mmartineau : 'add locks' is implemented in this patch 

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/fastopen.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 net/mptcp/protocol.c |  4 ++--
 net/mptcp/protocol.h |  5 +++++
 net/mptcp/sockopt.c  |  3 +++
 4 files changed, 50 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 9974508e0f4c..436e773d798a 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -16,6 +16,7 @@ int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 	struct socket *ssk;
 	int ret;
 
+	lock_sock((struct sock *)msk);
 	ssk = __mptcp_nmpc_socket(msk);
 	if (unlikely(!ssk))
 		goto out_EFAULT;
@@ -30,26 +31,63 @@ int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 		goto out_EFAULT;
 	uaddr = msg->msg_name;
 
+	lock_sock(ssk->sk);
+
 	tp = tcp_sk(ssk->sk);
 	if (unlikely(!tp))
-		goto out_EFAULT;
+		goto out_lock_EFAULT;
 	if (!tp->fastopen_req)
 		tp->fastopen_req = kzalloc(sizeof(*tp->fastopen_req),
 					   ssk->sk->sk_allocation);
 
 	if (unlikely(!tp->fastopen_req))
-		goto out_EFAULT;
+		goto out_lock_EFAULT;
 	tp->fastopen_req->data = msg;
 	tp->fastopen_req->size = len;
 	tp->fastopen_req->uarg = uarg;
 
+	release_sock(ssk->sk);
+	release_sock((struct sock *)msk);
+
 	/* requests a cookie */
 	ret = mptcp_stream_connect(sk->sk_socket, uaddr,
 				   msg->msg_namelen, msg->msg_flags);
 	if (!ret)
 		*copied = len;
 	return ret;
+
+out_lock_EFAULT:
+	release_sock(ssk->sk);
 out_EFAULT:
+	release_sock((struct sock *)msk);
 	ret = -EFAULT;
 	return ret;
 }
+
+int mptcp_setsockopt_sol_tcp_fastopen(struct mptcp_sock *msk, sockptr_t optval,
+				      unsigned int optlen)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct net *net = sock_net(sk);
+	int val;
+	int ret;
+
+	ret = 0;
+
+	if (copy_from_sockptr(&val, optval, sizeof(val)))
+		return -EFAULT;
+
+	lock_sock(sk);
+
+	if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
+	    TCPF_LISTEN))) {
+		tcp_fastopen_init_key_once(net);
+		fastopen_queue_tune(sk, val);
+	} else {
+		ret = -EINVAL;
+	}
+
+	release_sock(sk);
+
+	return ret;
+}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index ba50aa88d5d8..357767a84c57 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3474,8 +3474,8 @@ static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
 	__mptcp_do_fallback(msk);
 }
 
-static int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
-				int addr_len, int flags)
+int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr,
+			 int addr_len, int flags)
 {
 	struct mptcp_sock *msk = mptcp_sk(sock->sk);
 	struct mptcp_subflow_context *subflow;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 5cd14eacd1d6..2a4b6dfb6f8f 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -838,11 +838,16 @@ bool mptcp_userspace_pm_active(const struct mptcp_sock *msk);
 int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags);
 void mptcp_rmem_uncharge(struct sock *sk, int size);
 void mptcp_rfree(struct sk_buff *skb);
+int mptcp_stream_connect(struct socket *sock, struct sockaddr *uaddr, int addr_len, int flags);
+void mptcp_rmem_uncharge(struct sock *sk, int size);
+void mptcp_rfree(struct sk_buff *skb);
 
 // Fast Open Mechanism functions begin
 int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 			   size_t len, struct mptcp_sock *msk,
 			   size_t *copied);
+int mptcp_setsockopt_sol_tcp_fastopen(struct mptcp_sock *msk, sockptr_t optval,
+				      unsigned int optlen);
 // Fast Open Mechanism functions end
 
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 423d3826ca1e..f62f0d63b8e6 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -559,6 +559,7 @@ static bool mptcp_supported_sockopt(int level, int optname)
 		case TCP_NOTSENT_LOWAT:
 		case TCP_TX_DELAY:
 		case TCP_INQ:
+		case TCP_FASTOPEN:
 			return true;
 		}
 
@@ -796,6 +797,8 @@ static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname,
 		return mptcp_setsockopt_sol_tcp_nodelay(msk, optval, optlen);
 	case TCP_DEFER_ACCEPT:
 		return mptcp_setsockopt_sol_tcp_defer(msk, optval, optlen);
+	case TCP_FASTOPEN:
+		return mptcp_setsockopt_sol_tcp_fastopen(msk, optval, optlen);
 	}
 
 	return -EOPNOTSUPP;
-- 
2.25.1

[RFC PATCH mptcp-next v6 5/9] Fix unxpctd val of subflow->map_seq(dscrd packet)

[Dmytro Shytyi]

This fixes the unexpected value of subflow->map_seq for the 
second packet that leads to packet discard and further 
retransmit.

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/subflow.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index c7d49fb6e7bd..075c61d1d37f 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1077,8 +1077,10 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 		/* will validate the next map after consuming the current one */
 		goto validate_csum;
 	}
-
-	subflow->map_seq = map_seq;
+	if (msk->is_mptfo)
+		subflow->map_seq = READ_ONCE(msk->ack_seq);
+	else
+		subflow->map_seq = map_seq;
 	subflow->map_subflow_seq = mpext->subflow_seq;
 	subflow->map_data_len = data_len;
 	subflow->map_valid = 1;
-- 
2.25.1

[RFC PATCH mptcp-next v6 6/9] mptfo variables for msk, options. Fix loop retrans

[Dmytro Shytyi]

Introduce mptfo variables for msk and options. 
Also fixe the infinite retransmissions in the end of second session. 
Suggestion @palbeni (SEP 1) during the meting to 'look at data_ack'

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/fastopen.c | 16 ++++++++++++++++
 net/mptcp/options.c  |  3 +++
 net/mptcp/protocol.h |  6 +++++-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 436e773d798a..149a4b1d3dac 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -91,3 +91,19 @@ int mptcp_setsockopt_sol_tcp_fastopen(struct mptcp_sock *msk, sockptr_t optval,
 
 	return ret;
 }
+
+void mptcp_treat_hshake_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+				 struct mptcp_options_received mp_opt)
+{
+	u64 ack_seq;
+
+	if (mp_opt.suboptions & OPTIONS_MPTCP_MPC && mp_opt.is_mptfo && msk->is_mptfo) {
+		msk->can_ack = true;
+		msk->remote_key = mp_opt.sndr_key;
+		mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
+		ack_seq++;
+		WRITE_ONCE(msk->ack_seq, ack_seq);
+		pr_debug("ack_seq=%llu sndr_key=%llu", msk->ack_seq, mp_opt.sndr_key);
+		atomic64_set(&msk->rcv_wnd_sent, ack_seq);
+	}
+}
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 30d289044e71..185b069e57f4 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -91,6 +91,7 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 			ptr += 8;
 		}
 		if (opsize >= TCPOLEN_MPTCP_MPC_ACK) {
+			mp_opt->is_mptfo = 1;
 			mp_opt->rcvr_key = get_unaligned_be64(ptr);
 			ptr += 8;
 		}
@@ -1124,6 +1125,8 @@ bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
 		return sk->sk_state != TCP_CLOSE;
 
 	if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) {
+		mptcp_treat_hshake_ack_fastopen(msk, subflow, mp_opt);
+
 		if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) &&
 		    msk->local_key == mp_opt.rcvr_key) {
 			WRITE_ONCE(msk->rcv_fastclose, true);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 2a4b6dfb6f8f..c364616c2d56 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -155,7 +155,8 @@ struct mptcp_options_received {
 		echo:1,
 		backup:1,
 		deny_join_id0:1,
-		__unused:2;
+		is_mptfo:1,
+		__unused:1;
 	u8	join_id;
 	u64	thmac;
 	u8	hmac[MPTCPOPT_HMAC_LEN];
@@ -282,6 +283,7 @@ struct mptcp_sock {
 	bool		use_64bit_ack; /* Set when we received a 64-bit DSN */
 	bool		csum_enabled;
 	bool		allow_infinite_fallback;
+	bool		is_mptfo;
 	u8		mpc_endpoint_id;
 	u8		recvmsg_inq:1,
 			cork:1,
@@ -848,6 +850,8 @@ int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 			   size_t *copied);
 int mptcp_setsockopt_sol_tcp_fastopen(struct mptcp_sock *msk, sockptr_t optval,
 				      unsigned int optlen);
+void mptcp_treat_hshake_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+				     struct mptcp_options_received mp_opt);
 // Fast Open Mechanism functions end
 
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
-- 
2.25.1

[RFC PATCH mptcp-next v6 7/9] Listener: Add received skb to msk

[Dmytro Shytyi]

Add the received skb on the listener side to msk and set flag mptfo to 1 
to treat some parts only in MPTFO case. 
This function is called from the functions presented in the one of the 
patch of this serie (mptcp_add_skb helpers).

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/fastopen.c | 65 ++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.h | 43 +++++++++++++++++++++++++++++
 net/mptcp/subflow.c  |  2 +-
 3 files changed, 109 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 149a4b1d3dac..7070d2a966c9 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -107,3 +107,68 @@ void mptcp_treat_hshake_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflo
 		atomic64_set(&msk->rcv_wnd_sent, ack_seq);
 	}
 }
+
+void mptcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb, struct request_sock *req)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	struct tcp_request_sock *tcp_r_sock = tcp_rsk(req);
+	struct sock *socket = mptcp_subflow_ctx(sk)->conn;
+	struct mptcp_sock *msk = mptcp_sk(socket);
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	if (TCP_SKB_CB(skb)->end_seq == tp->rcv_nxt)
+		return;
+
+	skb = skb_clone(skb, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	skb_dst_drop(skb);
+
+	tp->segs_in = 0;
+	tcp_segs_in(tp, skb);
+	__skb_pull(skb, tcp_hdrlen(skb));
+	sk_forced_mem_schedule(sk, skb->truesize);
+
+	TCP_SKB_CB(skb)->seq++;
+	TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN;
+
+	tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+
+	msk->is_mptfo = 1;
+
+	//Solves: WARNING: at 704 _mptcp_move_skbs_from_subflow+0x5d0/0x651
+	tp->copied_seq += tp->rcv_nxt - tcp_r_sock->rcv_isn - 1;
+
+	TCP_SKB_CB(skb)->seq += tp->rcv_nxt - tcp_r_sock->rcv_isn - 1;
+	TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq;
+
+	TCP_SKB_CB(skb)->seq += tp->rcv_nxt - tcp_r_sock->rcv_isn - 1;
+	TCP_SKB_CB(skb)->end_seq =  TCP_SKB_CB(skb)->seq;
+
+	subflow->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
+
+	//Solves: BAD mapping: ssn=0 map_seq=1 map_data_len=3
+	subflow->ssn_offset = tp->copied_seq - 1;
+
+	skb_ext_reset(skb);
+
+	//mptcp_set_owner_r begin
+	skb_orphan(skb);
+	skb->sk = socket;
+	skb->destructor = mptcp_rfree;
+	atomic_add(skb->truesize, &socket->sk_rmem_alloc);
+	msk->rmem_fwd_alloc -= skb->truesize;
+	//mptcp_set owner_r end
+
+	__skb_queue_tail(&msk->receive_queue, skb);
+
+	atomic64_set(&msk->rcv_wnd_sent, mptcp_subflow_get_mapped_dsn(subflow));
+
+	tp->syn_data_acked = 1;
+
+	tp->bytes_received = skb->len;
+
+	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
+		tcp_fin(sk);
+}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index c364616c2d56..815d1bc6c6f2 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -852,6 +852,49 @@ int mptcp_setsockopt_sol_tcp_fastopen(struct mptcp_sock *msk, sockptr_t optval,
 				      unsigned int optlen);
 void mptcp_treat_hshake_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 				     struct mptcp_options_received mp_opt);
+void mptcp_treat_3d_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+				 struct mptcp_options_received mp_opt);
+void mptcp_treat_3d_ack_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
+				 struct mptcp_options_received mp_opt);
+void mptcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb,
+			    struct request_sock *req);
+void mptcp_reqsk_record_syn(const struct sock *sk,
+			    struct request_sock *req,
+			    const struct sk_buff *skb);
+void mptcp_ecn_create_request(struct request_sock *req,
+			      const struct sk_buff *skb,
+			      const struct sock *listen_sk,
+			      const struct dst_entry *dst);
+void mptcp_openreq_init(struct request_sock *req,
+			const struct tcp_options_received *rx_opt,
+			struct sk_buff *skb, const struct sock *sk);
+struct sock *mptcp_fastopen_create_child(struct sock *sk,
+					 struct sk_buff *skb,
+					 struct request_sock *req);
+bool mptcp_fastopen_queue_check(struct sock *sk);
+bool mptcp_fastopen_cookie_gen_cipher(struct request_sock *req,
+				      struct sk_buff *syn,
+				      const siphash_key_t *key,
+				      struct tcp_fastopen_cookie *foc);
+void mptcp_fastopen_cookie_gen(struct sock *sk,
+			       struct request_sock *req,
+			       struct sk_buff *syn,
+			       struct tcp_fastopen_cookie *foc);
+int mptcp_fastopen_cookie_gen_check(struct sock *sk,
+				    struct request_sock *req,
+				    struct sk_buff *syn,
+				    struct tcp_fastopen_cookie *orig,
+				    struct tcp_fastopen_cookie *valid_foc);
+bool mptcp_fastopen_no_cookie(const struct sock *sk,
+			      const struct dst_entry *dst,
+			      int flag);
+struct sock *mptcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
+				struct request_sock *req,
+				struct tcp_fastopen_cookie *foc,
+				const struct dst_entry *dst);
+int mptcp_conn_request(struct request_sock_ops *rsk_ops,
+		       const struct tcp_request_sock_ops *af_ops,
+		       struct sock *sk, struct sk_buff *skb);
 // Fast Open Mechanism functions end
 
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 075c61d1d37f..ff5fe4ff3d21 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -542,7 +542,7 @@ static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
 		goto drop;
 
-	return tcp_conn_request(&mptcp_subflow_request_sock_ops,
+	return mptcp_conn_request(&mptcp_subflow_request_sock_ops,
 				&subflow_request_sock_ipv4_ops,
 				sk, skb);
 drop:
-- 
2.25.1

[RFC PATCH mptcp-next v6 8/9] mptcp_fastopen_add_skb() helpers (skb to msk)

[Dmytro Shytyi]

Set of helpers for mptcp_skb_add(). Some functions are inspired from tcp
fastopen.c file. This chain helps to add “skb” to “&msk->sk_receive_queue”
(“subflow_v4_conn_request”->”mptcp_conn_request”->”mptcp_try_fastopen”->
”mptcp_fastopen_create_child”->”mptcp_fastopen_add_skb”)

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 net/mptcp/fastopen.c | 379 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 379 insertions(+)

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index 7070d2a966c9..815bae37097a 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -172,3 +172,382 @@ void mptcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb, struct request
 	if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 		tcp_fin(sk);
 }
+
+struct sock *mptcp_fastopen_create_child(struct sock *sk,
+					 struct sk_buff *skb,
+					 struct request_sock *req)
+{
+	struct request_sock_queue *r_sock_queue = &inet_csk(sk)->icsk_accept_queue;
+	struct tcp_sock *tp;
+	struct sock *child_sock;
+	bool own_req;
+
+	child_sock = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL,
+							      NULL, &own_req);
+	if (!child_sock)
+		return NULL;
+
+	spin_lock(&r_sock_queue->fastopenq.lock);
+	r_sock_queue->fastopenq.qlen++;
+	spin_unlock(&r_sock_queue->fastopenq.lock);
+
+	tp = tcp_sk(child_sock);
+
+	rcu_assign_pointer(tp->fastopen_rsk, req);
+	tcp_rsk(req)->tfo_listener = true;
+
+	tp->snd_wnd = ntohs(tcp_hdr(skb)->window);
+	tp->max_window = tp->snd_wnd;
+
+	inet_csk_reset_xmit_timer(child_sock, ICSK_TIME_RETRANS,
+				  TCP_TIMEOUT_INIT, TCP_RTO_MAX);
+
+	refcount_set(&req->rsk_refcnt, 2);
+
+	tcp_init_transfer(child_sock, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, skb);
+
+	tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
+
+	mptcp_fastopen_add_skb(child_sock, skb, req);
+
+	tcp_rsk(req)->rcv_nxt = tp->rcv_nxt;
+	tp->rcv_wup = tp->rcv_nxt;
+
+	return child_sock;
+}
+
+bool mptcp_fastopen_queue_check(struct sock *sk)
+{
+	struct fastopen_queue *fo_queue;
+	struct request_sock *req_sock;
+
+	fo_queue = &inet_csk(sk)->icsk_accept_queue.fastopenq;
+	if (fo_queue->max_qlen == 0)
+		return false;
+
+	if (fo_queue->qlen >= fo_queue->max_qlen) {
+		spin_lock(&fo_queue->lock);
+		req_sock = fo_queue->rskq_rst_head;
+		if (!req_sock || time_after(req_sock->rsk_timer.expires, jiffies)) {
+			spin_unlock(&fo_queue->lock);
+			return false;
+		}
+		fo_queue->rskq_rst_head = req_sock->dl_next;
+		fo_queue->qlen--;
+		spin_unlock(&fo_queue->lock);
+		reqsk_put(req_sock);
+	}
+	return true;
+}
+
+bool mptcp_fastopen_cookie_gen_cipher(struct request_sock *req,
+				      struct sk_buff *syn,
+				      const siphash_key_t *key,
+				      struct tcp_fastopen_cookie *foc)
+{
+	if (req->rsk_ops->family == AF_INET) {
+		const struct iphdr *iph = ip_hdr(syn);
+
+		foc->val[0] = cpu_to_le64(siphash(&iph->saddr,
+					  sizeof(iph->saddr) +
+					  sizeof(iph->daddr),
+					  key));
+		foc->len = TCP_FASTOPEN_COOKIE_SIZE;
+		return true;
+	}
+
+	return false;
+}
+
+void mptcp_fastopen_cookie_gen(struct sock *sk,
+			       struct request_sock *req,
+			       struct sk_buff *syn,
+			       struct tcp_fastopen_cookie *foc)
+{
+	struct tcp_fastopen_context *ctx;
+
+	rcu_read_lock();
+	ctx = tcp_fastopen_get_ctx(sk);
+	if (ctx)
+		mptcp_fastopen_cookie_gen_cipher(req, syn, &ctx->key[0], foc);
+	rcu_read_unlock();
+}
+
+int mptcp_fastopen_cookie_gen_check(struct sock *sk,
+				    struct request_sock *req,
+				    struct sk_buff *syn,
+				    struct tcp_fastopen_cookie *orig,
+				    struct tcp_fastopen_cookie *valid_foc)
+{
+	struct tcp_fastopen_cookie mptcp_search_foc = { .len = -1 };
+	struct tcp_fastopen_cookie *mptcp_foc = valid_foc;
+	struct tcp_fastopen_context *mptcp_fo_ctx;
+	int i, ret = 0;
+
+	rcu_read_lock();
+	mptcp_fo_ctx = tcp_fastopen_get_ctx(sk);
+	if (!mptcp_fo_ctx)
+		goto out;
+	for (i = 0; i < tcp_fastopen_context_len(mptcp_fo_ctx); i++) {
+		mptcp_fastopen_cookie_gen_cipher(req, syn, &mptcp_fo_ctx->key[i], mptcp_foc);
+		if (tcp_fastopen_cookie_match(mptcp_foc, orig)) {
+			ret = i + 1;
+			goto out;
+		}
+		mptcp_foc = &mptcp_search_foc;
+	}
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+bool mptcp_fastopen_no_cookie(const struct sock *sk,
+			      const struct dst_entry *dst,
+			      int flag)
+{
+	return (sock_net(sk)->ipv4.sysctl_tcp_fastopen & flag) ||
+	       tcp_sk(sk)->fastopen_no_cookie ||
+	       (dst && dst_metric(dst, RTAX_FASTOPEN_NO_COOKIE));
+}
+
+struct sock *mptcp_try_fastopen(struct sock *sk, struct sk_buff *skb,
+				struct request_sock *req,
+				struct tcp_fastopen_cookie *foc,
+				const struct dst_entry *dst)
+{
+	bool syn_data_status = TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1;
+	struct tcp_fastopen_cookie valid_mptcp_foc = { .len = -1 };
+	struct sock *child_sock;
+	int ret = 0;
+
+	if ((syn_data_status || foc->len >= 0) &&
+	    mptcp_fastopen_queue_check(sk)) {
+		foc->len = -1;
+		return NULL;
+	}
+
+	if (mptcp_fastopen_no_cookie(sk, dst, TFO_SERVER_COOKIE_NOT_REQD))
+		goto fastopen;
+
+	if (foc->len == 0) {
+		mptcp_fastopen_cookie_gen(sk, req, skb, &valid_mptcp_foc);
+	} else if (foc->len > 0) {
+		ret = mptcp_fastopen_cookie_gen_check(sk, req, skb, foc,
+						      &valid_mptcp_foc);
+		if (ret) {
+fastopen:
+			child_sock = mptcp_fastopen_create_child(sk, skb, req);
+			if (child_sock) {
+				if (ret == 2) {
+					valid_mptcp_foc.exp = foc->exp;
+					*foc = valid_mptcp_foc;
+				} else {
+					foc->len = -1;
+				}
+				return child_sock;
+			}
+		}
+	}
+	valid_mptcp_foc.exp = foc->exp;
+	*foc = valid_mptcp_foc;
+	return NULL;
+}
+
+int mptcp_conn_request(struct request_sock_ops *rsk_ops,
+		       const struct tcp_request_sock_ops *af_ops,
+		       struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_fastopen_cookie mptcp_foc = { .len = -1 };
+	struct tcp_options_received tmp_opt_rcvd;
+	__u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
+	struct tcp_sock *tp_sock = tcp_sk(sk);
+	struct sock *mptcp_fo_sk = NULL;
+	struct net *net = sock_net(sk);
+	struct request_sock *req_sock;
+	bool want_cookie = false;
+	struct dst_entry *dst;
+	struct flowi fl;
+
+	if (sk_acceptq_is_full(sk))
+		goto drop;
+
+	req_sock = inet_reqsk_alloc(rsk_ops, sk, !want_cookie);
+	if (!req_sock)
+		goto drop;
+
+	req_sock->syncookie = want_cookie;
+	tcp_rsk(req_sock)->af_specific = af_ops;
+	tcp_rsk(req_sock)->ts_off = 1;
+	tcp_rsk(req_sock)->is_mptcp = 1;
+
+	tcp_clear_options(&tmp_opt_rcvd);
+	tmp_opt_rcvd.mss_clamp = af_ops->mss_clamp;
+	tmp_opt_rcvd.user_mss  = tp_sock->rx_opt.user_mss;
+	tcp_parse_options(sock_net(sk), skb, &tmp_opt_rcvd, 0,
+			  want_cookie ? NULL : &mptcp_foc);
+
+	if (want_cookie && !tmp_opt_rcvd.saw_tstamp)
+		tcp_clear_options(&tmp_opt_rcvd);
+
+	if (IS_ENABLED(CONFIG_SMC) && want_cookie)
+		tmp_opt_rcvd.smc_ok = 0;
+
+	tmp_opt_rcvd.tstamp_ok = 0;
+	mptcp_openreq_init(req_sock, &tmp_opt_rcvd, skb, sk);
+	inet_rsk(req_sock)->no_srccheck = inet_sk(sk)->transparent;
+
+	inet_rsk(req_sock)->ir_iif = inet_request_bound_dev_if(sk, skb);
+
+	dst = af_ops->route_req(sk, skb, &fl, req_sock);
+	if (!dst)
+		goto drop_and_free;
+
+	if (tmp_opt_rcvd.tstamp_ok)
+		tcp_rsk(req_sock)->ts_off = af_ops->init_ts_off(net, skb);
+
+	if (!want_cookie && !isn) {
+		if (!net->ipv4.sysctl_tcp_syncookies &&
+		    (net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
+		     (net->ipv4.sysctl_max_syn_backlog >> 2)) &&
+		    !tcp_peer_is_proven(req_sock, dst)) {
+			goto drop_and_release;
+		}
+
+		isn = af_ops->init_seq(skb);
+	}
+
+	mptcp_ecn_create_request(req_sock, skb, sk, dst);
+
+	if (want_cookie) {
+		isn = cookie_init_sequence(af_ops, sk, skb, &req_sock->mss);
+		if (!tmp_opt_rcvd.tstamp_ok)
+			inet_rsk(req_sock)->ecn_ok = 0;
+	}
+
+	tcp_rsk(req_sock)->snt_isn = isn;
+	tcp_rsk(req_sock)->txhash = net_tx_rndhash();
+	tcp_rsk(req_sock)->syn_tos = TCP_SKB_CB(skb)->ip_dsfield;
+
+	tcp_openreq_init_rwin(req_sock, sk, dst);
+	sk_rx_queue_set(req_to_sk(req_sock), skb);
+	if (!want_cookie) {
+		mptcp_reqsk_record_syn(sk, req_sock, skb);
+		mptcp_fo_sk = mptcp_try_fastopen(sk, skb, req_sock, &mptcp_foc, dst);
+	}
+	if (mptcp_fo_sk) {
+		af_ops->send_synack(mptcp_fo_sk, dst, &fl, req_sock,
+				    &mptcp_foc, TCP_SYNACK_FASTOPEN, skb);
+		if (!inet_csk_reqsk_queue_add(sk, req_sock, mptcp_fo_sk)) {
+			reqsk_fastopen_remove(mptcp_fo_sk, req_sock, false);
+			bh_unlock_sock(mptcp_fo_sk);
+			sock_put(mptcp_fo_sk);
+			goto drop_and_free;
+		}
+		sk->sk_data_ready(sk);
+		bh_unlock_sock(mptcp_fo_sk);
+		sock_put(mptcp_fo_sk);
+	} else {
+		tcp_rsk(req_sock)->tfo_listener = false;
+		if (!want_cookie) {
+			req_sock->timeout = tcp_timeout_init((struct sock *)req_sock);
+			inet_csk_reqsk_queue_hash_add(sk, req_sock, req_sock->timeout);
+		}
+		af_ops->send_synack(sk, dst, &fl, req_sock, &mptcp_foc,
+				    !want_cookie ? TCP_SYNACK_NORMAL :
+						   TCP_SYNACK_COOKIE,
+				    skb);
+		if (want_cookie) {
+			reqsk_free(req_sock);
+			return 0;
+		}
+	}
+	reqsk_put(req_sock);
+	return 0;
+
+drop_and_release:
+	dst_release(dst);
+drop_and_free:
+	__reqsk_free(req_sock);
+drop:
+	tcp_listendrop(sk);
+	return 0;
+}
+
+void mptcp_reqsk_record_syn(const struct sock *sk,
+			    struct request_sock *req,
+			    const struct sk_buff *skb)
+{
+	if (tcp_sk(sk)->save_syn) {
+		u32 length = skb_network_header_len(skb) + tcp_hdrlen(skb);
+		struct saved_syn *svd_syn;
+		u32 mac_headerlen;
+		void *base;
+
+		if (tcp_sk(sk)->save_syn == 2) {
+			base = skb_mac_header(skb);
+			mac_headerlen = skb_mac_header_len(skb);
+			length += mac_headerlen;
+		} else {
+			base = skb_network_header(skb);
+			mac_headerlen = 0;
+		}
+
+		svd_syn = kmalloc(struct_size(svd_syn, data, length),
+				  GFP_ATOMIC);
+		if (svd_syn) {
+			svd_syn->mac_hdrlen = mac_headerlen;
+			svd_syn->network_hdrlen = skb_network_header_len(skb);
+			svd_syn->tcp_hdrlen = tcp_hdrlen(skb);
+			memcpy(svd_syn->data, base, length);
+			req->saved_syn = svd_syn;
+		}
+	}
+}
+
+void mptcp_ecn_create_request(struct request_sock *req,
+			      const struct sk_buff *skb,
+			      const struct sock *listen_sk,
+			      const struct dst_entry *dst)
+{
+	const struct tcphdr *thdr = tcp_hdr(skb);
+	const struct net *net = sock_net(listen_sk);
+	bool thdr_ecn = thdr->ece && thdr->cwr;
+	bool ect_stat, ecn_okay;
+	u32 ecn_okay_dst;
+
+	if (!thdr_ecn)
+		return;
+
+	ect_stat = !INET_ECN_is_not_ect(TCP_SKB_CB(skb)->ip_dsfield);
+	ecn_okay_dst = dst_feature(dst, DST_FEATURE_ECN_MASK);
+	ecn_okay = net->ipv4.sysctl_tcp_ecn || ecn_okay_dst;
+
+	if (((!ect_stat || thdr->res1) && ecn_okay) || tcp_ca_needs_ecn(listen_sk) ||
+	    (ecn_okay_dst & DST_FEATURE_ECN_CA) ||
+	    tcp_bpf_ca_needs_ecn((struct sock *)req))
+		inet_rsk(req)->ecn_ok = 1;
+}
+
+void mptcp_openreq_init(struct request_sock *req,
+			const struct tcp_options_received *rx_opt,
+			struct sk_buff *skb, const struct sock *sk)
+{
+	struct inet_request_sock *ireq = inet_rsk(req);
+
+	req->rsk_rcv_wnd = 0;
+	tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq;
+	tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->seq + 1;
+	tcp_rsk(req)->snt_synack = 0;
+	tcp_rsk(req)->last_oow_ack_time = 0;
+	req->mss = rx_opt->mss_clamp;
+	req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0;
+	ireq->tstamp_ok = rx_opt->tstamp_ok;
+	ireq->sack_ok = rx_opt->sack_ok;
+	ireq->snd_wscale = rx_opt->snd_wscale;
+	ireq->wscale_ok = rx_opt->wscale_ok;
+	ireq->acked = 0;
+	ireq->ecn_ok = 0;
+	ireq->ir_rmt_port = tcp_hdr(skb)->source;
+	ireq->ir_num = ntohs(tcp_hdr(skb)->dest);
+	ireq->ir_mark = inet_request_mark(sk, skb);
+}
-- 
2.25.1

[RFC PATCH mptcp-next v6 9/9] selftests: mptfo initiator/listener

[Dmytro Shytyi]

MPTFO tests: these are examples of initiator (sendto) and listener,
probably are going to be integrated to the mptcp_connect.* selftests

Signed-off-by: Dmytro Shytyi <dmytro@shytyi.net>
---
 tools/testing/selftests/net/mptcp/mptfo.sh    | 13 +++
 .../selftests/net/mptcp/mptfo_initiator.c     | 41 ++++++++
 .../selftests/net/mptcp/mptfo_listener.c      | 98 +++++++++++++++++++
 3 files changed, 152 insertions(+)
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo.sh
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo_initiator.c
 create mode 100644 tools/testing/selftests/net/mptcp/mptfo_listener.c

diff --git a/tools/testing/selftests/net/mptcp/mptfo.sh b/tools/testing/selftests/net/mptcp/mptfo.sh
new file mode 100644
index 000000000000..9ed0cb281094
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptfo.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+#This is an example of environmen that was used to generate wireshark
+sudo ip netns add server
+sudo ip netns add client
+sudo ip link add veth0 type veth peer name veth1
+sudo ip link set veth1 netns server
+sudo ip link set veth0 netns client
+sudo ip netns exec client ip a a 10.10.0.1/24 dev veth0
+sudo ip netns exec server ip a a 10.10.0.2/24 dev veth1
+sudo ip netns exec client ip link set dev  veth0 up
+sudo ip netns exec server ip link set dev  veth1 up
+sudo ip netns exec server bash -c "echo 2 > /proc/sys/net/ipv4/tcp_fastopen"
+sudo ip netns exec client bash -c "echo 1 > /proc/sys/net/ipv4/tcp_fastopen"
diff --git a/tools/testing/selftests/net/mptcp/mptfo_initiator.c b/tools/testing/selftests/net/mptcp/mptfo_initiator.c
new file mode 100644
index 000000000000..e23b88693fb0
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptfo_initiator.c
@@ -0,0 +1,41 @@
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <netinet/tcp.h>
+#include <string.h>
+#include <signal.h>
+
+#define SERVER_PORT 7003
+
+int main(int argc, char *argv[])
+{
+	unsigned char valsyn[3] = "abc";
+	struct sockaddr_in daddr;
+	char *valend = "fff";
+	char *val1 = "zz1";
+	char *val2 = "zz2";
+	char *val3 = "zz3";
+	int sock_fd = -1;
+	int ret;
+
+	memset(&daddr, 0, sizeof(daddr));
+	inet_pton(AF_INET, "10.10.0.2", &daddr.sin_addr);
+	daddr.sin_family = AF_INET;
+	daddr.sin_port = htons(SERVER_PORT);
+
+	sock_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);
+
+	ret = sendto(sock_fd, valsyn, 3, MSG_FASTOPEN, (struct sockaddr *) &daddr, sizeof(daddr));
+	ret = write(sock_fd, val1, 3);
+	ret = write(sock_fd, val2, 3);
+	ret = write(sock_fd, val2, 3);
+	ret = write(sock_fd, val2, 3);
+	ret = write(sock_fd, val3, 3);
+	ret = write(sock_fd, valend, 3);
+
+	close(sock_fd);
+	return EXIT_SUCCESS;
+}
diff --git a/tools/testing/selftests/net/mptcp/mptfo_listener.c b/tools/testing/selftests/net/mptcp/mptfo_listener.c
new file mode 100644
index 000000000000..7e3de8d1d08c
--- /dev/null
+++ b/tools/testing/selftests/net/mptcp/mptfo_listener.c
@@ -0,0 +1,98 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <netinet/in.h>
+#include <linux/in.h>
+#include <netinet/tcp.h>
+
+#define CLIENT_QUEUE_LEN 10
+#define SERVER_PORT 7003
+
+int main(void)
+{
+	int listen_sock_fd = -1, client_sock_fd = -1;
+	char str_addr[INET6_ADDRSTRLEN];
+	struct sockaddr_in server_addr;
+	int ret, flag;
+	int qlen = 5;
+	char ch;
+
+	server_addr.sin_family = AF_INET;
+	inet_pton(AF_INET, "10.10.0.2", &server_addr.sin_addr);
+	server_addr.sin_port = htons(SERVER_PORT);
+
+	/* Create socket for listening (client requests) */
+	listen_sock_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP);
+	if (listen_sock_fd == -1) {
+		perror("socket()server");
+		return EXIT_FAILURE;
+	}
+
+	/* Set socket to reuse address */
+	flag = 1;
+	ret = setsockopt(listen_sock_fd, SOL_SOCKET, SO_REUSEADDR, &flag, sizeof(flag));
+	if (ret == -1) {
+		perror("setsockopt()");
+		return EXIT_FAILURE;
+	}
+
+	ret = setsockopt(listen_sock_fd, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen));
+	if (ret == -1) {
+		perror("setsockopt()TCP_FASTOPEN");
+		return EXIT_FAILURE;
+	}
+
+	/* Bind address and socket together */
+	ret = bind(listen_sock_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));
+	if (ret == -1) {
+		perror("bind()");
+		close(listen_sock_fd);
+		return EXIT_FAILURE;
+	}
+
+	/* Create listening queue (client requests) */
+	ret = listen(listen_sock_fd, CLIENT_QUEUE_LEN);
+	if (ret == -1) {
+		perror("listen()");
+		close(listen_sock_fd);
+		return EXIT_FAILURE;
+	}
+	perror("Server listening");
+	while (1) {
+		/* Do TCP handshake with client */
+		client_sock_fd = accept(listen_sock_fd,
+				NULL,
+				0);
+		if (client_sock_fd == -1) {
+			perror("accept()");
+			close(listen_sock_fd);
+			return EXIT_FAILURE;
+		} else {
+			perror("ACCEPT_SUCCESS");
+		}
+
+		char rb[1024];
+
+		while (1) {
+			ret = read(client_sock_fd, rb, 3);
+
+			if (ret == -1) {
+				perror("SERVVERread()");
+				close(client_sock_fd);
+				break;
+			} else {
+				fprintf(stderr, "received %c%c%c from client", rb[0], rb[1], rb[2]);
+			}
+			if (rb[0] == 'f' && rb[1] == 'f' && rb[2] == 'f') {
+				close(client_sock_fd);
+				break;
+			}
+
+		}
+	}
+
+	return EXIT_SUCCESS;
+}
-- 
2.25.1

Re: selftests: mptfo initiator/listener: Build Failure

[MPTCP CI]

Hi Dmytro,

Thank you for your modifications, that's great!

But sadly, our CI spotted some issues with it when trying to build it.

You can find more details there:

  https://patchwork.kernel.org/project/mptcp/patch/20220915235604.26018-10-dmytro@shytyi.net/
  https://github.com/multipath-tcp/mptcp_net-next/actions/runs/3064785105

Status: failure
Initiator: MPTCPimporter
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/a04a47ac6e30

Feel free to reply to this email if you cannot access logs, if you need
some support to fix the error, if this doesn't seem to be caused by your
modifications or if the error is a false positive one.

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (Tessares)