xref: /openbmc/linux/net/dccp/ccids/ccid2.h (revision df2634f43f5106947f3735a0b61a6527a4b278cd)
1 /*
2  *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
3  *
4  *  This program is free software; you can redistribute it and/or modify
5  *  it under the terms of the GNU General Public License as published by
6  *  the Free Software Foundation; either version 2 of the License, or
7  *  (at your option) any later version.
8  *
9  *  This program is distributed in the hope that it will be useful,
10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  *  GNU General Public License for more details.
13  *
14  *  You should have received a copy of the GNU General Public License
15  *  along with this program; if not, write to the Free Software
16  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17  */
18 #ifndef _DCCP_CCID2_H_
19 #define _DCCP_CCID2_H_
20 
21 #include <linux/timer.h>
22 #include <linux/types.h>
23 #include "../ccid.h"
24 #include "../dccp.h"
25 
26 /*
27  * CCID-2 timestamping faces the same issues as TCP timestamping.
28  * Hence we reuse/share as much of the code as possible.
29  */
30 #define ccid2_time_stamp	tcp_time_stamp
31 
32 /* NUMDUPACK parameter from RFC 4341, p. 6 */
33 #define NUMDUPACK	3
34 
35 struct ccid2_seq {
36 	u64			ccid2s_seq;
37 	u32			ccid2s_sent;
38 	int			ccid2s_acked;
39 	struct ccid2_seq	*ccid2s_prev;
40 	struct ccid2_seq	*ccid2s_next;
41 };
42 
43 #define CCID2_SEQBUF_LEN 1024
44 #define CCID2_SEQBUF_MAX 128
45 
46 /**
47  * struct ccid2_hc_tx_sock - CCID2 TX half connection
48  * @tx_{cwnd,ssthresh,pipe}: as per RFC 4341, section 5
49  * @tx_packets_acked:	     Ack counter for deriving cwnd growth (RFC 3465)
50  * @tx_srtt:		     smoothed RTT estimate, scaled by 2^3
51  * @tx_mdev:		     smoothed RTT variation, scaled by 2^2
52  * @tx_mdev_max:	     maximum of @mdev during one flight
53  * @tx_rttvar:		     moving average/maximum of @mdev_max
54  * @tx_rto:		     RTO value deriving from SRTT and RTTVAR (RFC 2988)
55  * @tx_rtt_seq:		     to decay RTTVAR at most once per flight
56  * @tx_rpseq:		     last consecutive seqno
57  * @tx_rpdupack:	     dupacks since rpseq
58  * @tx_av_chunks:	     list of Ack Vectors received on current skb
59  */
60 struct ccid2_hc_tx_sock {
61 	u32			tx_cwnd;
62 	u32			tx_ssthresh;
63 	u32			tx_pipe;
64 	u32			tx_packets_acked;
65 	struct ccid2_seq	*tx_seqbuf[CCID2_SEQBUF_MAX];
66 	int			tx_seqbufc;
67 	struct ccid2_seq	*tx_seqh;
68 	struct ccid2_seq	*tx_seqt;
69 
70 	/* RTT measurement: variables/principles are the same as in TCP */
71 	u32			tx_srtt,
72 				tx_mdev,
73 				tx_mdev_max,
74 				tx_rttvar,
75 				tx_rto;
76 	u64			tx_rtt_seq:48;
77 	struct timer_list	tx_rtotimer;
78 
79 	u64			tx_rpseq;
80 	int			tx_rpdupack;
81 	u32			tx_last_cong;
82 	u64			tx_high_ack;
83 	struct list_head	tx_av_chunks;
84 };
85 
86 static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
87 {
88 	return hc->tx_pipe >= hc->tx_cwnd;
89 }
90 
91 struct ccid2_hc_rx_sock {
92 	int	rx_data;
93 };
94 
95 static inline struct ccid2_hc_tx_sock *ccid2_hc_tx_sk(const struct sock *sk)
96 {
97 	return ccid_priv(dccp_sk(sk)->dccps_hc_tx_ccid);
98 }
99 
100 static inline struct ccid2_hc_rx_sock *ccid2_hc_rx_sk(const struct sock *sk)
101 {
102 	return ccid_priv(dccp_sk(sk)->dccps_hc_rx_ccid);
103 }
104 #endif /* _DCCP_CCID2_H_ */
105