发送
tcp_sendmsg 将 skb 写入 meta_sk 的 sk_write_queue 然后复制一份skb，将 clone_skb 写入subsk的sk_write_queue。
相同的[seq, endseq]会同时存在meta_sk->sk_write_queue, meta_sk->reinject_queue, subsk->sk_write_queue
meta_sk->reinject_queue 跟 meta_sk->sk_write_queue 差不多，目前的pm中reinject_queue的发送优先级高于sk_write_queue。
reinject_queue 中skb的来源有：
重传时调mptcp_reinject_data将skb放到meta_sk的reinject_queue，也就是一个subsk重传skb，可以放到另一个subsk
subsk 调 tcp_write_queue_purge 时可能这些skb还是要发出去的，所以把skb放到meta_sk的reinject_queue
mptcp_sub_retransmit_timer, mptcp_del_sock, mptcp_send_reset_rem_id 等
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
| mptcp_write_wakeup
reinject = 0
mptcp_write_xmit
if (skb from reinject_queue)
reinject = 1
else
reinject = 0
mptcp_retransmit_skb
reinject = -1
-> mptcp_skb_entail(, skb, reinject)
-> mptcp_save_dss_data_seq 设置seq
-> tcp_add_write_queue_tail 或 tcp_transmit_skb
mptcp_sub_retransmit_timer
mptcp_del_sock
mptcp_send_reset_rem_id
tcp_write_queue_purge
-> mptcp_reinject_data
-> skb_queue_tail(meta_sk->reinject_queue, skb)
|
接收
1
2
3
4
5
6
7
8
9
10
11
12
13
14
| mptcp_data_ready
-> mptcp_queue_skb
-> tcp_queue_rcv(meta_sk, tmp1, 0, &fragstolen)
-> tcp_data_queue_ofo(meta_sk, tmp1);
tcp_validate_incoming
-> mptcp_handle_options
-> mptcp_process_data_ack
-> mptcp_clean_rtx_queue
-> 清理 meta_sk->sk_write_queue
-> 清理 mpcb->reinject_queue
tcp_ack
-> tcp_clean_rtx_queue
-> 清理 subsk->sk_write_queue
|
