1 /* 2 * net/dccp/ccids/lib/loss_interval.c 3 * 4 * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand. 5 * Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz> 6 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 */ 13 14 #include <linux/config.h> 15 #include <linux/module.h> 16 17 #include "loss_interval.h" 18 19 struct dccp_li_hist *dccp_li_hist_new(const char *name) 20 { 21 struct dccp_li_hist *hist = kmalloc(sizeof(*hist), GFP_ATOMIC); 22 static const char dccp_li_hist_mask[] = "li_hist_%s"; 23 char *slab_name; 24 25 if (hist == NULL) 26 goto out; 27 28 slab_name = kmalloc(strlen(name) + sizeof(dccp_li_hist_mask) - 1, 29 GFP_ATOMIC); 30 if (slab_name == NULL) 31 goto out_free_hist; 32 33 sprintf(slab_name, dccp_li_hist_mask, name); 34 hist->dccplih_slab = kmem_cache_create(slab_name, 35 sizeof(struct dccp_li_hist_entry), 36 0, SLAB_HWCACHE_ALIGN, 37 NULL, NULL); 38 if (hist->dccplih_slab == NULL) 39 goto out_free_slab_name; 40 out: 41 return hist; 42 out_free_slab_name: 43 kfree(slab_name); 44 out_free_hist: 45 kfree(hist); 46 hist = NULL; 47 goto out; 48 } 49 50 EXPORT_SYMBOL_GPL(dccp_li_hist_new); 51 52 void dccp_li_hist_delete(struct dccp_li_hist *hist) 53 { 54 const char* name = kmem_cache_name(hist->dccplih_slab); 55 56 kmem_cache_destroy(hist->dccplih_slab); 57 kfree(name); 58 kfree(hist); 59 } 60 61 EXPORT_SYMBOL_GPL(dccp_li_hist_delete); 62 63 void dccp_li_hist_purge(struct dccp_li_hist *hist, struct list_head *list) 64 { 65 struct dccp_li_hist_entry *entry, *next; 66 67 list_for_each_entry_safe(entry, next, list, dccplih_node) { 68 list_del_init(&entry->dccplih_node); 69 kmem_cache_free(hist->dccplih_slab, entry); 70 } 71 } 72 73 EXPORT_SYMBOL_GPL(dccp_li_hist_purge); 74 75 /* Weights used to calculate loss event rate */ 76 /* 77 * These are integers as per section 8 of RFC3448. We can then divide by 4 * 78 * when we use it. 79 */ 80 static const int dccp_li_hist_w[DCCP_LI_HIST_IVAL_F_LENGTH] = { 81 4, 4, 4, 4, 3, 2, 1, 1, 82 }; 83 84 u32 dccp_li_hist_calc_i_mean(struct list_head *list) 85 { 86 struct dccp_li_hist_entry *li_entry, *li_next; 87 int i = 0; 88 u32 i_tot; 89 u32 i_tot0 = 0; 90 u32 i_tot1 = 0; 91 u32 w_tot = 0; 92 93 list_for_each_entry_safe(li_entry, li_next, list, dccplih_node) { 94 if (i < DCCP_LI_HIST_IVAL_F_LENGTH) { 95 i_tot0 += li_entry->dccplih_interval * dccp_li_hist_w[i]; 96 w_tot += dccp_li_hist_w[i]; 97 } 98 99 if (i != 0) 100 i_tot1 += li_entry->dccplih_interval * dccp_li_hist_w[i - 1]; 101 102 if (++i > DCCP_LI_HIST_IVAL_F_LENGTH) 103 break; 104 } 105 106 if (i != DCCP_LI_HIST_IVAL_F_LENGTH) 107 return 0; 108 109 i_tot = max(i_tot0, i_tot1); 110 111 /* FIXME: Why do we do this? -Ian McDonald */ 112 if (i_tot * 4 < w_tot) 113 i_tot = w_tot * 4; 114 115 return i_tot * 4 / w_tot; 116 } 117 118 EXPORT_SYMBOL_GPL(dccp_li_hist_calc_i_mean); 119 120 struct dccp_li_hist_entry *dccp_li_hist_interval_new(struct dccp_li_hist *hist, 121 struct list_head *list, 122 const u64 seq_loss, 123 const u8 win_loss) 124 { 125 struct dccp_li_hist_entry *tail = NULL, *entry; 126 int i; 127 128 for (i = 0; i <= DCCP_LI_HIST_IVAL_F_LENGTH; ++i) { 129 entry = dccp_li_hist_entry_new(hist, SLAB_ATOMIC); 130 if (entry == NULL) { 131 dccp_li_hist_purge(hist, list); 132 return NULL; 133 } 134 if (tail == NULL) 135 tail = entry; 136 list_add(&entry->dccplih_node, list); 137 } 138 139 entry->dccplih_seqno = seq_loss; 140 entry->dccplih_win_count = win_loss; 141 return tail; 142 } 143 144 EXPORT_SYMBOL_GPL(dccp_li_hist_interval_new); 145