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

[Dmytro Shytyi <dmytro@shytyi.net>]

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