1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/kernel.h> 32 #include <sys/lock.h> 33 #include <sys/mutex.h> 34 #include <sys/proc.h> 35 #include <sys/sched.h> 36 #include <sys/smp.h> 37 #include <sys/sysctl.h> 38 #include <vm/uma.h> 39 40 #define IN_SUBR_COUNTER_C 41 #include <sys/counter.h> 42 43 static MALLOC_DEFINE(M_COUNTER_RATE, "counter_rate", "counter rate allocations"); 44 45 void 46 counter_u64_zero(counter_u64_t c) 47 { 48 49 counter_u64_zero_inline(c); 50 } 51 52 uint64_t 53 counter_u64_fetch(counter_u64_t c) 54 { 55 56 return (counter_u64_fetch_inline(c)); 57 } 58 59 counter_u64_t 60 counter_u64_alloc(int flags) 61 { 62 63 return (uma_zalloc_pcpu(pcpu_zone_8, flags | M_ZERO)); 64 } 65 66 void 67 counter_u64_free(counter_u64_t c) 68 { 69 70 uma_zfree_pcpu(pcpu_zone_8, c); 71 } 72 73 int 74 sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS) 75 { 76 uint64_t out; 77 int error; 78 79 out = counter_u64_fetch(*(counter_u64_t *)arg1); 80 81 error = SYSCTL_OUT(req, &out, sizeof(uint64_t)); 82 83 if (error || !req->newptr) 84 return (error); 85 86 /* 87 * Any write attempt to a counter zeroes it. 88 */ 89 counter_u64_zero(*(counter_u64_t *)arg1); 90 91 return (0); 92 } 93 94 int 95 sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS) 96 { 97 uint64_t *out; 98 int error; 99 100 out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK); 101 for (int i = 0; i < arg2; i++) 102 out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]); 103 104 error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t)); 105 free(out, M_TEMP); 106 107 if (error || !req->newptr) 108 return (error); 109 110 /* 111 * Any write attempt to a counter zeroes it. 112 */ 113 for (int i = 0; i < arg2; i++) 114 counter_u64_zero(((counter_u64_t *)arg1)[i]); 115 116 return (0); 117 } 118 119 /* 120 * counter(9) based rate checking. 121 */ 122 struct counter_rate { 123 counter_u64_t cr_rate; /* Events since last second */ 124 volatile int cr_lock; /* Lock to clean the struct */ 125 int cr_ticks; /* Ticks on last clean */ 126 int cr_over; /* Over limit since cr_ticks? */ 127 int cr_period; /* Allow cr_rate per cr_period seconds. */ 128 }; 129 130 struct counter_rate * 131 counter_rate_alloc(int flags, int period) 132 { 133 struct counter_rate *new; 134 135 new = malloc(sizeof(struct counter_rate), M_COUNTER_RATE, 136 flags | M_ZERO); 137 if (new == NULL) 138 return (NULL); 139 140 new->cr_rate = counter_u64_alloc(flags); 141 if (new->cr_rate == NULL) { 142 free(new, M_COUNTER_RATE); 143 return (NULL); 144 } 145 new->cr_ticks = ticks; 146 new->cr_period = period; 147 148 return (new); 149 } 150 151 void 152 counter_rate_free(struct counter_rate *rate) 153 { 154 if (rate == NULL) 155 return; 156 157 counter_u64_free(rate->cr_rate); 158 free(rate, M_COUNTER_RATE); 159 } 160 161 uint64_t 162 counter_rate_get(struct counter_rate *cr) 163 { 164 if (cr->cr_ticks < (tick - (hz * cr->cr_period))) 165 return (0); 166 167 return (counter_u64_fetch(cr->cr_rate)); 168 } 169 170 /* 171 * MP-friendly version of ppsratecheck(). 172 * 173 * Returns non-negative if we are in the rate, negative otherwise. 174 * 0 - rate limit not reached. 175 * -1 - rate limit reached. 176 * >0 - rate limit was reached before, and was just reset. The return value 177 * is number of events since last reset. 178 */ 179 int64_t 180 counter_ratecheck(struct counter_rate *cr, int64_t limit) 181 { 182 int64_t val; 183 int now; 184 185 val = cr->cr_over; 186 now = ticks; 187 188 if ((u_int)(now - cr->cr_ticks) >= (hz * cr->cr_period)) { 189 /* 190 * Time to clear the structure, we are in the next second. 191 * First try unlocked read, and then proceed with atomic. 192 */ 193 if ((cr->cr_lock == 0) && 194 atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) { 195 /* 196 * Check if other thread has just went through the 197 * reset sequence before us. 198 */ 199 if ((u_int)(now - cr->cr_ticks) >= (hz * cr->cr_period)) { 200 val = counter_u64_fetch(cr->cr_rate); 201 counter_u64_zero(cr->cr_rate); 202 cr->cr_over = 0; 203 cr->cr_ticks = now; 204 if (val <= limit) 205 val = 0; 206 } 207 atomic_store_rel_int(&cr->cr_lock, 0); 208 } else 209 /* 210 * We failed to lock, in this case other thread may 211 * be running counter_u64_zero(), so it is not safe 212 * to do an update, we skip it. 213 */ 214 return (val); 215 } 216 217 counter_u64_add(cr->cr_rate, 1); 218 if (cr->cr_over != 0) 219 return (-1); 220 if (counter_u64_fetch(cr->cr_rate) > limit) 221 val = cr->cr_over = -1; 222 223 return (val); 224 } 225 226 void 227 counter_u64_sysinit(void *arg) 228 { 229 counter_u64_t *cp; 230 231 cp = arg; 232 *cp = counter_u64_alloc(M_WAITOK); 233 } 234 235 void 236 counter_u64_sysuninit(void *arg) 237 { 238 counter_u64_t *cp; 239 240 cp = arg; 241 counter_u64_free(*cp); 242 } 243