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      1 /*	$NetBSD: tcp_congctl.h,v 1.7 2013/11/12 09:02:05 kefren Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Rui Paulo.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _NETINET_TCP_CONGCTL_H
     33 #define _NETINET_TCP_CONGCTL_H
     34 
     35 #define TCPCC_MAXLEN 12
     36 
     37 struct tcp_congctlent {
     38 	TAILQ_ENTRY(tcp_congctlent) congctl_ent;
     39 	const struct tcp_congctl *congctl_ctl;
     40 	unsigned int congctl_refcnt;
     41 	char congctl_name[TCPCC_MAXLEN];
     42 };
     43 /*
     44  * Congestion control function table.
     45  */
     46 struct tcp_congctl {
     47 	/*
     48 	 * fast_retransmit: called on tcprexmtthresh'th dup ACKs.
     49 	 * this actually retransmits packets by calling tcp_output()
     50 	 * if appropriate.
     51 	 * returns 0 if entering fast recovery.  otherwise returns non-0.
     52 	 */
     53 	int  (*fast_retransmit)(struct tcpcb *, const struct tcphdr *);
     54 
     55 	/*
     56 	 * slow_retransmit: called on RTO to adjust parameters like cwnd.
     57 	 */
     58 	void (*slow_retransmit)(struct tcpcb *);
     59 
     60 	/*
     61 	 * fast_retransmit_newack: called when new data is acked.
     62 	 * ie. when advancing SND.UNA
     63 	 * not called if TCP_SACK_ENABLED.
     64 	 */
     65 	void (*fast_retransmit_newack)(struct tcpcb *, const struct tcphdr *);
     66 
     67 	/*
     68 	 * newack: called when new data is acked.  ie. when advancing SND.UNA
     69 	 * it's called before updating tp->snd_una.
     70 	 */
     71 	void (*newack)(struct tcpcb *, const struct tcphdr *);
     72 
     73 	/*
     74 	 * cong_exp: called when congestion is detected.  eg. by ECN
     75 	 */
     76 	void (*cong_exp)(struct tcpcb *);
     77 };
     78 
     79 extern const struct tcp_congctl tcp_reno_ctl;
     80 extern const struct tcp_congctl tcp_newreno_ctl;
     81 extern const struct tcp_congctl tcp_cubic_ctl;
     82 
     83 /* currently selected global congestion control */
     84 extern char tcp_congctl_global_name[TCPCC_MAXLEN];
     85 
     86 /* available global congestion control algorithms */
     87 extern char tcp_congctl_avail[10 * TCPCC_MAXLEN];
     88 
     89 void   tcp_congctl_init(void);
     90 int    tcp_congctl_register(const char *, const struct tcp_congctl *);
     91 int    tcp_congctl_unregister(const char *);
     92 int    tcp_congctl_select(struct tcpcb *, const char *);
     93 void   tcp_congctl_release(struct tcpcb *);
     94 const char *
     95        tcp_congctl_bystruct(const struct tcp_congctl *);
     96 
     97 #endif /* _NETINET_TCP_CONGCTL_H */
     98