samples/bpf/hbm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2019 Facebook
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * Example program for Host Bandwidth Managment
   9  *
  10  * This program loads a cgroup skb BPF program to enforce cgroup output
  11  * (egress) or input (ingress) bandwidth limits.
  12  *
  13  * USAGE: hbm [-d] [-l] [-n <id>] [-r <rate>] [-s] [-t <secs>] [-w] [-h] [prog]
  14  *   Where:
  15  *    -d        Print BPF trace debug buffer
  16  *    -l        Also limit flows doing loopback
  17  *    -n <#>    To create cgroup \"/hbm#\" and attach prog
  18  *              Default is /hbm1
  19  *    --no_cn   Do not return cn notifications
  20  *    -r <rate> Rate limit in Mbps
  21  *    -s        Get HBM stats (marked, dropped, etc.)
  22  *    -t <time> Exit after specified seconds (default is 0)
  23  *    -w        Work conserving flag. cgroup can increase its bandwidth
  24  *              beyond the rate limit specified while there is available
  25  *              bandwidth. Current implementation assumes there is only
  26  *              NIC (eth0), but can be extended to support multiple NICs.
  27  *              Currrently only supported for egress.
  28  *    -h        Print this info
  29  *    prog      BPF program file name. Name defaults to hbm_out_kern.o
  30  */
  31
  32 #define _GNU_SOURCE
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <assert.h>
  37 #include <sys/resource.h>
  38 #include <sys/time.h>
  39 #include <unistd.h>
  40 #include <errno.h>
  41 #include <fcntl.h>
  42 #include <linux/unistd.h>
  43
  44 #include <linux/bpf.h>
  45 #include <bpf/bpf.h>
  46 #include <getopt.h>
  47
  48 #include "bpf_load.h"
  49 #include "bpf_rlimit.h"
  50 #include "cgroup_helpers.h"
  51 #include "hbm.h"
  52 #include "bpf_util.h"
  53 #include "bpf.h"
  54 #include "libbpf.h"
  55
  56 bool outFlag = true;
  57 int minRate = 1000;             /* cgroup rate limit in Mbps */
  58 int rate = 1000;                /* can grow if rate conserving is enabled */
  59 int dur = 1;
  60 bool stats_flag;
  61 bool loopback_flag;
  62 bool debugFlag;
  63 bool work_conserving_flag;
  64 bool no_cn_flag;
  65
  66 static void Usage(void);
  67 static void read_trace_pipe2(void);
  68 static void do_error(char *msg, bool errno_flag);
  69
  70 #define DEBUGFS "/sys/kernel/debug/tracing/"
  71
  72 struct bpf_object *obj;
  73 int bpfprog_fd;
  74 int cgroup_storage_fd;
  75
  76 static void read_trace_pipe2(void)
  77 {
  78         int trace_fd;
  79         FILE *outf;
  80         char *outFname = "hbm_out.log";
  81
  82         trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
  83         if (trace_fd < 0) {
  84                 printf("Error opening trace_pipe\n");
  85                 return;
  86         }
  87
  88 //      Future support of ingress
  89 //      if (!outFlag)
  90 //              outFname = "hbm_in.log";
  91         outf = fopen(outFname, "w");
  92
  93         if (outf == NULL)
  94                 printf("Error creating %s\n", outFname);
  95
  96         while (1) {
  97                 static char buf[4097];
  98                 ssize_t sz;
  99
 100                 sz = read(trace_fd, buf, sizeof(buf) - 1);
 101                 if (sz > 0) {
 102                         buf[sz] = 0;
 103                         puts(buf);
 104                         if (outf != NULL) {
 105                                 fprintf(outf, "%s\n", buf);
 106                                 fflush(outf);
 107                         }
 108                 }
 109         }
 110 }
 111
 112 static void do_error(char *msg, bool errno_flag)
 113 {
 114         if (errno_flag)
 115                 printf("ERROR: %s, errno: %d\n", msg, errno);
 116         else
 117                 printf("ERROR: %s\n", msg);
 118         exit(1);
 119 }
 120
 121 static int prog_load(char *prog)
 122 {
 123         struct bpf_prog_load_attr prog_load_attr = {
 124                 .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
 125                 .file = prog,
 126                 .expected_attach_type = BPF_CGROUP_INET_EGRESS,
 127         };
 128         int map_fd;
 129         struct bpf_map *map;
 130
 131         int ret = 0;
 132
 133         if (access(prog, O_RDONLY) < 0) {
 134                 printf("Error accessing file %s: %s\n", prog, strerror(errno));
 135                 return 1;
 136         }
 137         if (bpf_prog_load_xattr(&prog_load_attr, &obj, &bpfprog_fd))
 138                 ret = 1;
 139         if (!ret) {
 140                 map = bpf_object__find_map_by_name(obj, "queue_stats");
 141                 map_fd = bpf_map__fd(map);
 142                 if (map_fd < 0) {
 143                         printf("Map not found: %s\n", strerror(map_fd));
 144                         ret = 1;
 145                 }
 146         }
 147
 148         if (ret) {
 149                 printf("ERROR: load_bpf_file failed for: %s\n", prog);
 150                 printf("  Output from verifier:\n%s\n------\n", bpf_log_buf);
 151                 ret = -1;
 152         } else {
 153                 ret = map_fd;
 154         }
 155
 156         return ret;
 157 }
 158
 159 static int run_bpf_prog(char *prog, int cg_id)
 160 {
 161         int map_fd;
 162         int rc = 0;
 163         int key = 0;
 164         int cg1 = 0;
 165         int type = BPF_CGROUP_INET_EGRESS;
 166         char cg_dir[100];
 167         struct hbm_queue_stats qstats = {0};
 168
 169         sprintf(cg_dir, "/hbm%d", cg_id);
 170         map_fd = prog_load(prog);
 171         if (map_fd  == -1)
 172                 return 1;
 173
 174         if (setup_cgroup_environment()) {
 175                 printf("ERROR: setting cgroup environment\n");
 176                 goto err;
 177         }
 178         cg1 = create_and_get_cgroup(cg_dir);
 179         if (!cg1) {
 180                 printf("ERROR: create_and_get_cgroup\n");
 181                 goto err;
 182         }
 183         if (join_cgroup(cg_dir)) {
 184                 printf("ERROR: join_cgroup\n");
 185                 goto err;
 186         }
 187
 188         qstats.rate = rate;
 189         qstats.stats = stats_flag ? 1 : 0;
 190         qstats.loopback = loopback_flag ? 1 : 0;
 191         qstats.no_cn = no_cn_flag ? 1 : 0;
 192         if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY)) {
 193                 printf("ERROR: Could not update map element\n");
 194                 goto err;
 195         }
 196
 197         if (!outFlag)
 198                 type = BPF_CGROUP_INET_INGRESS;
 199         if (bpf_prog_attach(bpfprog_fd, cg1, type, 0)) {
 200                 printf("ERROR: bpf_prog_attach fails!\n");
 201                 log_err("Attaching prog");
 202                 goto err;
 203         }
 204
 205         if (work_conserving_flag) {
 206                 struct timeval t0, t_last, t_new;
 207                 FILE *fin;
 208                 unsigned long long last_eth_tx_bytes, new_eth_tx_bytes;
 209                 signed long long last_cg_tx_bytes, new_cg_tx_bytes;
 210                 signed long long delta_time, delta_bytes, delta_rate;
 211                 int delta_ms;
 212 #define DELTA_RATE_CHECK 10000          /* in us */
 213 #define RATE_THRESHOLD 9500000000       /* 9.5 Gbps */
 214
 215                 bpf_map_lookup_elem(map_fd, &key, &qstats);
 216                 if (gettimeofday(&t0, NULL) < 0)
 217                         do_error("gettimeofday failed", true);
 218                 t_last = t0;
 219                 fin = fopen("/sys/class/net/eth0/statistics/tx_bytes", "r");
 220                 if (fscanf(fin, "%llu", &last_eth_tx_bytes) != 1)
 221                         do_error("fscanf fails", false);
 222                 fclose(fin);
 223                 last_cg_tx_bytes = qstats.bytes_total;
 224                 while (true) {
 225                         usleep(DELTA_RATE_CHECK);
 226                         if (gettimeofday(&t_new, NULL) < 0)
 227                                 do_error("gettimeofday failed", true);
 228                         delta_ms = (t_new.tv_sec - t0.tv_sec) * 1000 +
 229                                 (t_new.tv_usec - t0.tv_usec)/1000;
 230                         if (delta_ms > dur * 1000)
 231                                 break;
 232                         delta_time = (t_new.tv_sec - t_last.tv_sec) * 1000000 +
 233                                 (t_new.tv_usec - t_last.tv_usec);
 234                         if (delta_time == 0)
 235                                 continue;
 236                         t_last = t_new;
 237                         fin = fopen("/sys/class/net/eth0/statistics/tx_bytes",
 238                                     "r");
 239                         if (fscanf(fin, "%llu", &new_eth_tx_bytes) != 1)
 240                                 do_error("fscanf fails", false);
 241                         fclose(fin);
 242                         printf("  new_eth_tx_bytes:%llu\n",
 243                                new_eth_tx_bytes);
 244                         bpf_map_lookup_elem(map_fd, &key, &qstats);
 245                         new_cg_tx_bytes = qstats.bytes_total;
 246                         delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
 247                         last_eth_tx_bytes = new_eth_tx_bytes;
 248                         delta_rate = (delta_bytes * 8000000) / delta_time;
 249                         printf("%5d - eth_rate:%.1fGbps cg_rate:%.3fGbps",
 250                                delta_ms, delta_rate/1000000000.0,
 251                                rate/1000.0);
 252                         if (delta_rate < RATE_THRESHOLD) {
 253                                 /* can increase cgroup rate limit, but first
 254                                  * check if we are using the current limit.
 255                                  * Currently increasing by 6.25%, unknown
 256                                  * if that is the optimal rate.
 257                                  */
 258                                 int rate_diff100;
 259
 260                                 delta_bytes = new_cg_tx_bytes -
 261                                         last_cg_tx_bytes;
 262                                 last_cg_tx_bytes = new_cg_tx_bytes;
 263                                 delta_rate = (delta_bytes * 8000000) /
 264                                         delta_time;
 265                                 printf(" rate:%.3fGbps",
 266                                        delta_rate/1000000000.0);
 267                                 rate_diff100 = (((long long)rate)*1000000 -
 268                                                      delta_rate) * 100 /
 269                                         (((long long) rate) * 1000000);
 270                                 printf("  rdiff:%d", rate_diff100);
 271                                 if (rate_diff100  <= 3) {
 272                                         rate += (rate >> 4);
 273                                         if (rate > RATE_THRESHOLD / 1000000)
 274                                                 rate = RATE_THRESHOLD / 1000000;
 275                                         qstats.rate = rate;
 276                                         printf(" INC\n");
 277                                 } else {
 278                                         printf("\n");
 279                                 }
 280                         } else {
 281                                 /* Need to decrease cgroup rate limit.
 282                                  * Currently decreasing by 12.5%, unknown
 283                                  * if that is optimal
 284                                  */
 285                                 printf(" DEC\n");
 286                                 rate -= (rate >> 3);
 287                                 if (rate < minRate)
 288                                         rate = minRate;
 289                                 qstats.rate = rate;
 290                         }
 291                         if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY))
 292                                 do_error("update map element fails", false);
 293                 }
 294         } else {
 295                 sleep(dur);
 296         }
 297         // Get stats!
 298         if (stats_flag && bpf_map_lookup_elem(map_fd, &key, &qstats)) {
 299                 char fname[100];
 300                 FILE *fout;
 301
 302                 if (!outFlag)
 303                         sprintf(fname, "hbm.%d.in", cg_id);
 304                 else
 305                         sprintf(fname, "hbm.%d.out", cg_id);
 306                 fout = fopen(fname, "w");
 307                 fprintf(fout, "id:%d\n", cg_id);
 308                 fprintf(fout, "ERROR: Could not lookup queue_stats\n");
 309         } else if (stats_flag && qstats.lastPacketTime >
 310                    qstats.firstPacketTime) {
 311                 long long delta_us = (qstats.lastPacketTime -
 312                                       qstats.firstPacketTime)/1000;
 313                 unsigned int rate_mbps = ((qstats.bytes_total -
 314                                            qstats.bytes_dropped) * 8 /
 315                                           delta_us);
 316                 double percent_pkts, percent_bytes;
 317                 char fname[100];
 318                 FILE *fout;
 319                 int k;
 320                 static const char *returnValNames[] = {
 321                         "DROP_PKT",
 322                         "ALLOW_PKT",
 323                         "DROP_PKT_CWR",
 324                         "ALLOW_PKT_CWR"
 325                 };
 326 #define RET_VAL_COUNT 4
 327
 328 // Future support of ingress
 329 //              if (!outFlag)
 330 //                      sprintf(fname, "hbm.%d.in", cg_id);
 331 //              else
 332                 sprintf(fname, "hbm.%d.out", cg_id);
 333                 fout = fopen(fname, "w");
 334                 fprintf(fout, "id:%d\n", cg_id);
 335                 fprintf(fout, "rate_mbps:%d\n", rate_mbps);
 336                 fprintf(fout, "duration:%.1f secs\n",
 337                         (qstats.lastPacketTime - qstats.firstPacketTime) /
 338                         1000000000.0);
 339                 fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
 340                 fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
 341                                                      1000000));
 342                 fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
 343                 fprintf(fout, "bytes_dropped_MB:%d\n",
 344                         (int)(qstats.bytes_dropped /
 345                                                        1000000));
 346                 // Marked Pkts and Bytes
 347                 percent_pkts = (qstats.pkts_marked * 100.0) /
 348                         (qstats.pkts_total + 1);
 349                 percent_bytes = (qstats.bytes_marked * 100.0) /
 350                         (qstats.bytes_total + 1);
 351                 fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
 352                 fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
 353
 354                 // Dropped Pkts and Bytes
 355                 percent_pkts = (qstats.pkts_dropped * 100.0) /
 356                         (qstats.pkts_total + 1);
 357                 percent_bytes = (qstats.bytes_dropped * 100.0) /
 358                         (qstats.bytes_total + 1);
 359                 fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
 360                 fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
 361
 362                 // ECN CE markings
 363                 percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
 364                         (qstats.pkts_total + 1);
 365                 fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
 366                         (int)qstats.pkts_ecn_ce);
 367
 368                 // Average cwnd
 369                 fprintf(fout, "avg cwnd:%d\n",
 370                         (int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
 371                 // Average rtt
 372                 fprintf(fout, "avg rtt:%d\n",
 373                         (int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
 374                 // Average credit
 375                 fprintf(fout, "avg credit:%d\n",
 376                         (int)(qstats.sum_credit /
 377                               (1500 * ((int)qstats.pkts_total) + 1)));
 378
 379                 // Return values stats
 380                 for (k = 0; k < RET_VAL_COUNT; k++) {
 381                         percent_pkts = (qstats.returnValCount[k] * 100.0) /
 382                                 (qstats.pkts_total + 1);
 383                         fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
 384                                 percent_pkts, (int)qstats.returnValCount[k]);
 385                 }
 386                 fclose(fout);
 387         }
 388
 389         if (debugFlag)
 390                 read_trace_pipe2();
 391         return rc;
 392 err:
 393         rc = 1;
 394
 395         if (cg1)
 396                 close(cg1);
 397         cleanup_cgroup_environment();
 398
 399         return rc;
 400 }
 401
 402 static void Usage(void)
 403 {
 404         printf("This program loads a cgroup skb BPF program to enforce\n"
 405                "cgroup output (egress) bandwidth limits.\n\n"
 406                "USAGE: hbm [-o] [-d]  [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
 407                "           [-s] [-t <secs>] [-w] [-h] [prog]\n"
 408                "  Where:\n"
 409                "    -o         indicates egress direction (default)\n"
 410                "    -d         print BPF trace debug buffer\n"
 411                "    -l         also limit flows using loopback\n"
 412                "    -n <#>     to create cgroup \"/hbm#\" and attach prog\n"
 413                "               Default is /hbm1\n"
 414                "    --no_cn    disable CN notifications\n"
 415                "    -r <rate>  Rate in Mbps\n"
 416                "    -s         Update HBM stats\n"
 417                "    -t <time>  Exit after specified seconds (default is 0)\n"
 418                "    -w         Work conserving flag. cgroup can increase\n"
 419                "               bandwidth beyond the rate limit specified\n"
 420                "               while there is available bandwidth. Current\n"
 421                "               implementation assumes there is only eth0\n"
 422                "               but can be extended to support multiple NICs\n"
 423                "    -h         print this info\n"
 424                "    prog       BPF program file name. Name defaults to\n"
 425                "                 hbm_out_kern.o\n");
 426 }
 427
 428 int main(int argc, char **argv)
 429 {
 430         char *prog = "hbm_out_kern.o";
 431         int  k;
 432         int cg_id = 1;
 433         char *optstring = "iodln:r:st:wh";
 434         struct option loptions[] = {
 435                 {"no_cn", 0, NULL, 1},
 436                 {NULL, 0, NULL, 0}
 437         };
 438
 439         while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
 440                 switch (k) {
 441                 case 1:
 442                         no_cn_flag = true;
 443                         break;
 444                 case'o':
 445                         break;
 446                 case 'd':
 447                         debugFlag = true;
 448                         break;
 449                 case 'l':
 450                         loopback_flag = true;
 451                         break;
 452                 case 'n':
 453                         cg_id = atoi(optarg);
 454                         break;
 455                 case 'r':
 456                         minRate = atoi(optarg) * 1.024;
 457                         rate = minRate;
 458                         break;
 459                 case 's':
 460                         stats_flag = true;
 461                         break;
 462                 case 't':
 463                         dur = atoi(optarg);
 464                         break;
 465                 case 'w':
 466                         work_conserving_flag = true;
 467                         break;
 468                 case '?':
 469                         if (optopt == 'n' || optopt == 'r' || optopt == 't')
 470                                 fprintf(stderr,
 471                                         "Option -%c requires an argument.\n\n",
 472                                         optopt);
 473                 case 'h':
 474                         // fallthrough
 475                 default:
 476                         Usage();
 477                         return 0;
 478                 }
 479         }
 480
 481         if (optind < argc)
 482                 prog = argv[optind];
 483         printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
 484
 485         return run_bpf_prog(prog, cg_id);
 486 }