net/mptcp/fastopen.c

   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
   9 void mptcp_fastopen_subflow_synack_set_params(struct mptcp_subflow_context *subflow,
  10                                               struct request_sock *req)
  11 {
  12         struct sock *sk, *ssk;
  13         struct sk_buff *skb;
  14         struct tcp_sock *tp;
  15
  16         /* on early fallback the subflow context is deleted by
  17          * subflow_syn_recv_sock()
  18          */
  19         if (!subflow)
  20                 return;
  21
  22         ssk = subflow->tcp_sock;
  23         sk = subflow->conn;
  24         tp = tcp_sk(ssk);
  25
  26         subflow->is_mptfo = 1;
  27
  28         skb = skb_peek(&ssk->sk_receive_queue);
  29         if (WARN_ON_ONCE(!skb))
  30                 return;
  31
  32         /* dequeue the skb from sk receive queue */
  33         __skb_unlink(skb, &ssk->sk_receive_queue);
  34         skb_ext_reset(skb);
  35         skb_orphan(skb);
  36
  37         /* We copy the fastopen data, but that don't belong to the mptcp sequence
  38          * space, need to offset it in the subflow sequence, see mptcp_subflow_get_map_offset()
  39          */
  40         tp->copied_seq += skb->len;
  41         subflow->ssn_offset += skb->len;
  42
  43         /* initialize a dummy sequence number, we will update it at MPC
  44          * completion, if needed
  45          */
  46         MPTCP_SKB_CB(skb)->map_seq = -skb->len;
  47         MPTCP_SKB_CB(skb)->end_seq = 0;
  48         MPTCP_SKB_CB(skb)->offset = 0;
  49         MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
  50
  51         mptcp_data_lock(sk);
  52
  53         mptcp_set_owner_r(skb, sk);
  54         __skb_queue_tail(&sk->sk_receive_queue, skb);
  55         mptcp_sk(sk)->bytes_received += skb->len;
  56
  57         sk->sk_data_ready(sk);
  58
  59         mptcp_data_unlock(sk);
  60 }
  61
  62 void __mptcp_fastopen_gen_msk_ackseq(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
  63                                      const struct mptcp_options_received *mp_opt)
  64 {
  65         struct sock *sk = (struct sock *)msk;
  66         struct sk_buff *skb;
  67
  68         skb = skb_peek_tail(&sk->sk_receive_queue);
  69         if (skb) {
  70                 WARN_ON_ONCE(MPTCP_SKB_CB(skb)->end_seq);
  71                 pr_debug("msk %p moving seq %llx -> %llx end_seq %llx -> %llx\n", sk,
  72                          MPTCP_SKB_CB(skb)->map_seq, MPTCP_SKB_CB(skb)->map_seq + msk->ack_seq,
  73                          MPTCP_SKB_CB(skb)->end_seq, MPTCP_SKB_CB(skb)->end_seq + msk->ack_seq);
  74                 MPTCP_SKB_CB(skb)->map_seq += msk->ack_seq;
  75                 MPTCP_SKB_CB(skb)->end_seq += msk->ack_seq;
  76         }
  77
  78         pr_debug("msk=%p ack_seq=%llx\n", msk, msk->ack_seq);
  79 }