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      1 /*	$NetBSD: ieee80211_amrr.c,v 1.3 2015/08/24 20:58:47 pooka Exp $	*/
      2 /*	$OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $	*/
      3 
      4 /*-
      5  * Copyright (c) 2006
      6  *	Damien Bergamini <damien.bergamini (at) free.fr>
      7  *
      8  * Permission to use, copy, modify, and distribute this software for any
      9  * purpose with or without fee is hereby granted, provided that the above
     10  * copyright notice and this permission notice appear in all copies.
     11  *
     12  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     13  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     14  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     15  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     16  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     17  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     18  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     19  */
     20 
     21 #include <sys/cdefs.h>
     22 __KERNEL_RCSID(0, "$NetBSD: ieee80211_amrr.c,v 1.3 2015/08/24 20:58:47 pooka Exp $");
     23 
     24 #ifdef _KERNEL_OPT
     25 #include "opt_inet.h"
     26 #endif
     27 
     28 #include <sys/param.h>
     29 #include <sys/kernel.h>
     30 #include <sys/socket.h>
     31 #include <sys/sysctl.h>
     32 
     33 #include <net/if.h>
     34 #include <net/if_ether.h>
     35 #include <net/if_media.h>
     36 
     37 #ifdef INET
     38 #include <netinet/in.h>
     39 #endif
     40 
     41 #include <net80211/ieee80211.h>
     42 #include <net80211/ieee80211_var.h>
     43 #include <net80211/ieee80211_amrr.h>
     44 
     45 #define is_success(amn)	\
     46 	((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
     47 #define is_failure(amn)	\
     48 	((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
     49 #define is_enough(amn)		\
     50 	((amn)->amn_txcnt > 10)
     51 #define is_min_rate(ni)		\
     52 	((ni)->ni_txrate == 0)
     53 #define is_max_rate(ni)		\
     54 	((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1)
     55 #define increase_rate(ni)	\
     56 	((ni)->ni_txrate++)
     57 #define decrease_rate(ni)	\
     58 	((ni)->ni_txrate--)
     59 #define reset_cnt(amn)		\
     60 	do { (amn)->amn_txcnt = (amn)->amn_retrycnt = 0; } while (0)
     61 
     62 void
     63 ieee80211_amrr_node_init(struct ieee80211_amrr *amrr,
     64     struct ieee80211_amrr_node *amn)
     65 {
     66 	amn->amn_success = 0;
     67 	amn->amn_recovery = 0;
     68 	amn->amn_txcnt = amn->amn_retrycnt = 0;
     69 	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
     70 }
     71 
     72 /*
     73  * Update ni->ni_txrate.
     74  */
     75 void
     76 ieee80211_amrr_choose(struct ieee80211_amrr *amrr, struct ieee80211_node *ni,
     77     struct ieee80211_amrr_node *amn)
     78 {
     79 	int need_change = 0;
     80 
     81 	if (is_success(amn) && is_enough(amn)) {
     82 		amn->amn_success++;
     83 		if (amn->amn_success >= amn->amn_success_threshold &&
     84 		    !is_max_rate(ni)) {
     85 			amn->amn_recovery = 1;
     86 			amn->amn_success = 0;
     87 			increase_rate(ni);
     88 			IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_DEBUG,
     89 			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)\n",
     90 			    ni->ni_rates.rs_rates[ni->ni_txrate] &
     91 				IEEE80211_RATE_VAL,
     92 			    amn->amn_txcnt, amn->amn_retrycnt);
     93 			need_change = 1;
     94 		} else {
     95 			amn->amn_recovery = 0;
     96 		}
     97 	} else if (is_failure(amn)) {
     98 		amn->amn_success = 0;
     99 		if (!is_min_rate(ni)) {
    100 			if (amn->amn_recovery) {
    101 				amn->amn_success_threshold *= 2;
    102 				if (amn->amn_success_threshold >
    103 				    amrr->amrr_max_success_threshold)
    104 					amn->amn_success_threshold =
    105 					    amrr->amrr_max_success_threshold;
    106 			} else {
    107 				amn->amn_success_threshold =
    108 				    amrr->amrr_min_success_threshold;
    109 			}
    110 			decrease_rate(ni);
    111 			IEEE80211_DPRINTF(ni->ni_ic, IEEE80211_MSG_DEBUG,
    112 			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)\n",
    113 			    ni->ni_rates.rs_rates[ni->ni_txrate] &
    114 				IEEE80211_RATE_VAL,
    115 			    amn->amn_txcnt, amn->amn_retrycnt);
    116 			need_change = 1;
    117 		}
    118 		amn->amn_recovery = 0;
    119 	}
    120 
    121 	if (is_enough(amn) || need_change)
    122 		reset_cnt(amn);
    123 }
    124