1// SPDX-License-Identifier: GPL-2.0
 2/* MPTCP Fast Open Mechanism
 3 *
 4 * Copyright (c) 2021-2022, Dmytro SHYTYI
 5 */
 6
 7#include "protocol.h"
 8
 9void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
10					      struct request_sock *req)
11{
12	struct sock *ssk = subflow->tcp_sock;
13	struct sock *sk = subflow->conn;
14	struct sk_buff *skb;
15	struct tcp_sock *tp;
16
17	tp = tcp_sk(ssk);
18
19	subflow->is_mptfo = 1;
20
21	skb = skb_peek(&ssk->sk_receive_queue);
22	if (WARN_ON_ONCE(!skb))
23		return;
24
25	/* dequeue the skb from sk receive queue */
26	__skb_unlink(skb, &ssk->sk_receive_queue);
27	skb_ext_reset(skb);
28	skb_orphan(skb);
29
30	/* We copy the fastopen data, but that don't belong to the mptcp sequence
31	 * space, need to offset it in the subflow sequence, see mptcp_subflow_get_map_offset()
32	 */
33	tp->copied_seq += skb->len;
34	subflow->ssn_offset += skb->len;
35
36	/* initialize a dummy sequence number, we will update it at MPC
37	 * completion, if needed
38	 */
39	MPTCP_SKB_CB(skb)->map_seq = -skb->len;
40	MPTCP_SKB_CB(skb)->end_seq = 0;
41	MPTCP_SKB_CB(skb)->offset = 0;
42	MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
43
44	mptcp_data_lock(sk);
45
46	mptcp_set_owner_r(skb, sk);
47	__skb_queue_tail(&sk->sk_receive_queue, skb);
48
49	sk->sk_data_ready(sk);
50
51	mptcp_data_unlock(sk);
52}
53
54void mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
55				   const struct mptcp_options_received *mp_opt)
56{
57	struct sock *sk = (struct sock *)msk;
58	struct sk_buff *skb;
59
60	mptcp_data_lock(sk);
61	skb = skb_peek_tail(&sk->sk_receive_queue);
62	if (skb) {
63		WARN_ON_ONCE(MPTCP_SKB_CB(skb)->end_seq);
64		pr_debug("msk %p moving seq %llx -> %llx end_seq %llx -> %llx", sk,
65			 MPTCP_SKB_CB(skb)->map_seq, MPTCP_SKB_CB(skb)->map_seq + msk->ack_seq,
66			 MPTCP_SKB_CB(skb)->end_seq, MPTCP_SKB_CB(skb)->end_seq + msk->ack_seq);
67		MPTCP_SKB_CB(skb)->map_seq += msk->ack_seq;
68		MPTCP_SKB_CB(skb)->end_seq += msk->ack_seq;
69	}
70
71	pr_debug("msk=%p ack_seq=%llx", msk, msk->ack_seq);
72	mptcp_data_unlock(sk);
73}