linux/samples/bpf/hbm.c
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   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
  56bool outFlag = true;
  57int minRate = 1000;             /* cgroup rate limit in Mbps */
  58int rate = 1000;                /* can grow if rate conserving is enabled */
  59int dur = 1;
  60bool stats_flag;
  61bool loopback_flag;
  62bool debugFlag;
  63bool work_conserving_flag;
  64bool no_cn_flag;
  65bool edt_flag;
  66
  67static void Usage(void);
  68static void read_trace_pipe2(void);
  69static void do_error(char *msg, bool errno_flag);
  70
  71#define DEBUGFS "/sys/kernel/debug/tracing/"
  72
  73struct bpf_object *obj;
  74int bpfprog_fd;
  75int cgroup_storage_fd;
  76
  77static void read_trace_pipe2(void)
  78{
  79        int trace_fd;
  80        FILE *outf;
  81        char *outFname = "hbm_out.log";
  82
  83        trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
  84        if (trace_fd < 0) {
  85                printf("Error opening trace_pipe\n");
  86                return;
  87        }
  88
  89//      Future support of ingress
  90//      if (!outFlag)
  91//              outFname = "hbm_in.log";
  92        outf = fopen(outFname, "w");
  93
  94        if (outf == NULL)
  95                printf("Error creating %s\n", outFname);
  96
  97        while (1) {
  98                static char buf[4097];
  99                ssize_t sz;
 100
 101                sz = read(trace_fd, buf, sizeof(buf) - 1);
 102                if (sz > 0) {
 103                        buf[sz] = 0;
 104                        puts(buf);
 105                        if (outf != NULL) {
 106                                fprintf(outf, "%s\n", buf);
 107                                fflush(outf);
 108                        }
 109                }
 110        }
 111}
 112
 113static void do_error(char *msg, bool errno_flag)
 114{
 115        if (errno_flag)
 116                printf("ERROR: %s, errno: %d\n", msg, errno);
 117        else
 118                printf("ERROR: %s\n", msg);
 119        exit(1);
 120}
 121
 122static int prog_load(char *prog)
 123{
 124        struct bpf_prog_load_attr prog_load_attr = {
 125                .prog_type = BPF_PROG_TYPE_CGROUP_SKB,
 126                .file = prog,
 127                .expected_attach_type = BPF_CGROUP_INET_EGRESS,
 128        };
 129        int map_fd;
 130        struct bpf_map *map;
 131
 132        int ret = 0;
 133
 134        if (access(prog, O_RDONLY) < 0) {
 135                printf("Error accessing file %s: %s\n", prog, strerror(errno));
 136                return 1;
 137        }
 138        if (bpf_prog_load_xattr(&prog_load_attr, &obj, &bpfprog_fd))
 139                ret = 1;
 140        if (!ret) {
 141                map = bpf_object__find_map_by_name(obj, "queue_stats");
 142                map_fd = bpf_map__fd(map);
 143                if (map_fd < 0) {
 144                        printf("Map not found: %s\n", strerror(map_fd));
 145                        ret = 1;
 146                }
 147        }
 148
 149        if (ret) {
 150                printf("ERROR: load_bpf_file failed for: %s\n", prog);
 151                printf("  Output from verifier:\n%s\n------\n", bpf_log_buf);
 152                ret = -1;
 153        } else {
 154                ret = map_fd;
 155        }
 156
 157        return ret;
 158}
 159
 160static int run_bpf_prog(char *prog, int cg_id)
 161{
 162        int map_fd;
 163        int rc = 0;
 164        int key = 0;
 165        int cg1 = 0;
 166        int type = BPF_CGROUP_INET_EGRESS;
 167        char cg_dir[100];
 168        struct hbm_queue_stats qstats = {0};
 169
 170        sprintf(cg_dir, "/hbm%d", cg_id);
 171        map_fd = prog_load(prog);
 172        if (map_fd  == -1)
 173                return 1;
 174
 175        if (setup_cgroup_environment()) {
 176                printf("ERROR: setting cgroup environment\n");
 177                goto err;
 178        }
 179        cg1 = create_and_get_cgroup(cg_dir);
 180        if (!cg1) {
 181                printf("ERROR: create_and_get_cgroup\n");
 182                goto err;
 183        }
 184        if (join_cgroup(cg_dir)) {
 185                printf("ERROR: join_cgroup\n");
 186                goto err;
 187        }
 188
 189        qstats.rate = rate;
 190        qstats.stats = stats_flag ? 1 : 0;
 191        qstats.loopback = loopback_flag ? 1 : 0;
 192        qstats.no_cn = no_cn_flag ? 1 : 0;
 193        if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY)) {
 194                printf("ERROR: Could not update map element\n");
 195                goto err;
 196        }
 197
 198        if (!outFlag)
 199                type = BPF_CGROUP_INET_INGRESS;
 200        if (bpf_prog_attach(bpfprog_fd, cg1, type, 0)) {
 201                printf("ERROR: bpf_prog_attach fails!\n");
 202                log_err("Attaching prog");
 203                goto err;
 204        }
 205
 206        if (work_conserving_flag) {
 207                struct timeval t0, t_last, t_new;
 208                FILE *fin;
 209                unsigned long long last_eth_tx_bytes, new_eth_tx_bytes;
 210                signed long long last_cg_tx_bytes, new_cg_tx_bytes;
 211                signed long long delta_time, delta_bytes, delta_rate;
 212                int delta_ms;
 213#define DELTA_RATE_CHECK 10000          /* in us */
 214#define RATE_THRESHOLD 9500000000       /* 9.5 Gbps */
 215
 216                bpf_map_lookup_elem(map_fd, &key, &qstats);
 217                if (gettimeofday(&t0, NULL) < 0)
 218                        do_error("gettimeofday failed", true);
 219                t_last = t0;
 220                fin = fopen("/sys/class/net/eth0/statistics/tx_bytes", "r");
 221                if (fscanf(fin, "%llu", &last_eth_tx_bytes) != 1)
 222                        do_error("fscanf fails", false);
 223                fclose(fin);
 224                last_cg_tx_bytes = qstats.bytes_total;
 225                while (true) {
 226                        usleep(DELTA_RATE_CHECK);
 227                        if (gettimeofday(&t_new, NULL) < 0)
 228                                do_error("gettimeofday failed", true);
 229                        delta_ms = (t_new.tv_sec - t0.tv_sec) * 1000 +
 230                                (t_new.tv_usec - t0.tv_usec)/1000;
 231                        if (delta_ms > dur * 1000)
 232                                break;
 233                        delta_time = (t_new.tv_sec - t_last.tv_sec) * 1000000 +
 234                                (t_new.tv_usec - t_last.tv_usec);
 235                        if (delta_time == 0)
 236                                continue;
 237                        t_last = t_new;
 238                        fin = fopen("/sys/class/net/eth0/statistics/tx_bytes",
 239                                    "r");
 240                        if (fscanf(fin, "%llu", &new_eth_tx_bytes) != 1)
 241                                do_error("fscanf fails", false);
 242                        fclose(fin);
 243                        printf("  new_eth_tx_bytes:%llu\n",
 244                               new_eth_tx_bytes);
 245                        bpf_map_lookup_elem(map_fd, &key, &qstats);
 246                        new_cg_tx_bytes = qstats.bytes_total;
 247                        delta_bytes = new_eth_tx_bytes - last_eth_tx_bytes;
 248                        last_eth_tx_bytes = new_eth_tx_bytes;
 249                        delta_rate = (delta_bytes * 8000000) / delta_time;
 250                        printf("%5d - eth_rate:%.1fGbps cg_rate:%.3fGbps",
 251                               delta_ms, delta_rate/1000000000.0,
 252                               rate/1000.0);
 253                        if (delta_rate < RATE_THRESHOLD) {
 254                                /* can increase cgroup rate limit, but first
 255                                 * check if we are using the current limit.
 256                                 * Currently increasing by 6.25%, unknown
 257                                 * if that is the optimal rate.
 258                                 */
 259                                int rate_diff100;
 260
 261                                delta_bytes = new_cg_tx_bytes -
 262                                        last_cg_tx_bytes;
 263                                last_cg_tx_bytes = new_cg_tx_bytes;
 264                                delta_rate = (delta_bytes * 8000000) /
 265                                        delta_time;
 266                                printf(" rate:%.3fGbps",
 267                                       delta_rate/1000000000.0);
 268                                rate_diff100 = (((long long)rate)*1000000 -
 269                                                     delta_rate) * 100 /
 270                                        (((long long) rate) * 1000000);
 271                                printf("  rdiff:%d", rate_diff100);
 272                                if (rate_diff100  <= 3) {
 273                                        rate += (rate >> 4);
 274                                        if (rate > RATE_THRESHOLD / 1000000)
 275                                                rate = RATE_THRESHOLD / 1000000;
 276                                        qstats.rate = rate;
 277                                        printf(" INC\n");
 278                                } else {
 279                                        printf("\n");
 280                                }
 281                        } else {
 282                                /* Need to decrease cgroup rate limit.
 283                                 * Currently decreasing by 12.5%, unknown
 284                                 * if that is optimal
 285                                 */
 286                                printf(" DEC\n");
 287                                rate -= (rate >> 3);
 288                                if (rate < minRate)
 289                                        rate = minRate;
 290                                qstats.rate = rate;
 291                        }
 292                        if (bpf_map_update_elem(map_fd, &key, &qstats, BPF_ANY))
 293                                do_error("update map element fails", false);
 294                }
 295        } else {
 296                sleep(dur);
 297        }
 298        // Get stats!
 299        if (stats_flag && bpf_map_lookup_elem(map_fd, &key, &qstats)) {
 300                char fname[100];
 301                FILE *fout;
 302
 303                if (!outFlag)
 304                        sprintf(fname, "hbm.%d.in", cg_id);
 305                else
 306                        sprintf(fname, "hbm.%d.out", cg_id);
 307                fout = fopen(fname, "w");
 308                fprintf(fout, "id:%d\n", cg_id);
 309                fprintf(fout, "ERROR: Could not lookup queue_stats\n");
 310        } else if (stats_flag && qstats.lastPacketTime >
 311                   qstats.firstPacketTime) {
 312                long long delta_us = (qstats.lastPacketTime -
 313                                      qstats.firstPacketTime)/1000;
 314                unsigned int rate_mbps = ((qstats.bytes_total -
 315                                           qstats.bytes_dropped) * 8 /
 316                                          delta_us);
 317                double percent_pkts, percent_bytes;
 318                char fname[100];
 319                FILE *fout;
 320                int k;
 321                static const char *returnValNames[] = {
 322                        "DROP_PKT",
 323                        "ALLOW_PKT",
 324                        "DROP_PKT_CWR",
 325                        "ALLOW_PKT_CWR"
 326                };
 327#define RET_VAL_COUNT 4
 328
 329// Future support of ingress
 330//              if (!outFlag)
 331//                      sprintf(fname, "hbm.%d.in", cg_id);
 332//              else
 333                sprintf(fname, "hbm.%d.out", cg_id);
 334                fout = fopen(fname, "w");
 335                fprintf(fout, "id:%d\n", cg_id);
 336                fprintf(fout, "rate_mbps:%d\n", rate_mbps);
 337                fprintf(fout, "duration:%.1f secs\n",
 338                        (qstats.lastPacketTime - qstats.firstPacketTime) /
 339                        1000000000.0);
 340                fprintf(fout, "packets:%d\n", (int)qstats.pkts_total);
 341                fprintf(fout, "bytes_MB:%d\n", (int)(qstats.bytes_total /
 342                                                     1000000));
 343                fprintf(fout, "pkts_dropped:%d\n", (int)qstats.pkts_dropped);
 344                fprintf(fout, "bytes_dropped_MB:%d\n",
 345                        (int)(qstats.bytes_dropped /
 346                                                       1000000));
 347                // Marked Pkts and Bytes
 348                percent_pkts = (qstats.pkts_marked * 100.0) /
 349                        (qstats.pkts_total + 1);
 350                percent_bytes = (qstats.bytes_marked * 100.0) /
 351                        (qstats.bytes_total + 1);
 352                fprintf(fout, "pkts_marked_percent:%6.2f\n", percent_pkts);
 353                fprintf(fout, "bytes_marked_percent:%6.2f\n", percent_bytes);
 354
 355                // Dropped Pkts and Bytes
 356                percent_pkts = (qstats.pkts_dropped * 100.0) /
 357                        (qstats.pkts_total + 1);
 358                percent_bytes = (qstats.bytes_dropped * 100.0) /
 359                        (qstats.bytes_total + 1);
 360                fprintf(fout, "pkts_dropped_percent:%6.2f\n", percent_pkts);
 361                fprintf(fout, "bytes_dropped_percent:%6.2f\n", percent_bytes);
 362
 363                // ECN CE markings
 364                percent_pkts = (qstats.pkts_ecn_ce * 100.0) /
 365                        (qstats.pkts_total + 1);
 366                fprintf(fout, "pkts_ecn_ce:%6.2f (%d)\n", percent_pkts,
 367                        (int)qstats.pkts_ecn_ce);
 368
 369                // Average cwnd
 370                fprintf(fout, "avg cwnd:%d\n",
 371                        (int)(qstats.sum_cwnd / (qstats.sum_cwnd_cnt + 1)));
 372                // Average rtt
 373                fprintf(fout, "avg rtt:%d\n",
 374                        (int)(qstats.sum_rtt / (qstats.pkts_total + 1)));
 375                // Average credit
 376                if (edt_flag)
 377                        fprintf(fout, "avg credit_ms:%.03f\n",
 378                                (qstats.sum_credit /
 379                                 (qstats.pkts_total + 1.0)) / 1000000.0);
 380                else
 381                        fprintf(fout, "avg credit:%d\n",
 382                                (int)(qstats.sum_credit /
 383                                      (1500 * ((int)qstats.pkts_total ) + 1)));
 384
 385                // Return values stats
 386                for (k = 0; k < RET_VAL_COUNT; k++) {
 387                        percent_pkts = (qstats.returnValCount[k] * 100.0) /
 388                                (qstats.pkts_total + 1);
 389                        fprintf(fout, "%s:%6.2f (%d)\n", returnValNames[k],
 390                                percent_pkts, (int)qstats.returnValCount[k]);
 391                }
 392                fclose(fout);
 393        }
 394
 395        if (debugFlag)
 396                read_trace_pipe2();
 397        return rc;
 398err:
 399        rc = 1;
 400
 401        if (cg1)
 402                close(cg1);
 403        cleanup_cgroup_environment();
 404
 405        return rc;
 406}
 407
 408static void Usage(void)
 409{
 410        printf("This program loads a cgroup skb BPF program to enforce\n"
 411               "cgroup output (egress) bandwidth limits.\n\n"
 412               "USAGE: hbm [-o] [-d]  [-l] [-n <id>] [--no_cn] [-r <rate>]\n"
 413               "           [-s] [-t <secs>] [-w] [-h] [prog]\n"
 414               "  Where:\n"
 415               "    -o         indicates egress direction (default)\n"
 416               "    -d         print BPF trace debug buffer\n"
 417               "    --edt      use fq's Earliest Departure Time\n"
 418               "    -l         also limit flows using loopback\n"
 419               "    -n <#>     to create cgroup \"/hbm#\" and attach prog\n"
 420               "               Default is /hbm1\n"
 421               "    --no_cn    disable CN notifications\n"
 422               "    -r <rate>  Rate in Mbps\n"
 423               "    -s         Update HBM stats\n"
 424               "    -t <time>  Exit after specified seconds (default is 0)\n"
 425               "    -w         Work conserving flag. cgroup can increase\n"
 426               "               bandwidth beyond the rate limit specified\n"
 427               "               while there is available bandwidth. Current\n"
 428               "               implementation assumes there is only eth0\n"
 429               "               but can be extended to support multiple NICs\n"
 430               "    -h         print this info\n"
 431               "    prog       BPF program file name. Name defaults to\n"
 432               "                 hbm_out_kern.o\n");
 433}
 434
 435int main(int argc, char **argv)
 436{
 437        char *prog = "hbm_out_kern.o";
 438        int  k;
 439        int cg_id = 1;
 440        char *optstring = "iodln:r:st:wh";
 441        struct option loptions[] = {
 442                {"no_cn", 0, NULL, 1},
 443                {"edt", 0, NULL, 2},
 444                {NULL, 0, NULL, 0}
 445        };
 446
 447        while ((k = getopt_long(argc, argv, optstring, loptions, NULL)) != -1) {
 448                switch (k) {
 449                case 1:
 450                        no_cn_flag = true;
 451                        break;
 452                case 2:
 453                        prog = "hbm_edt_kern.o";
 454                        edt_flag = true;
 455                        break;
 456                case'o':
 457                        break;
 458                case 'd':
 459                        debugFlag = true;
 460                        break;
 461                case 'l':
 462                        loopback_flag = true;
 463                        break;
 464                case 'n':
 465                        cg_id = atoi(optarg);
 466                        break;
 467                case 'r':
 468                        minRate = atoi(optarg) * 1.024;
 469                        rate = minRate;
 470                        break;
 471                case 's':
 472                        stats_flag = true;
 473                        break;
 474                case 't':
 475                        dur = atoi(optarg);
 476                        break;
 477                case 'w':
 478                        work_conserving_flag = true;
 479                        break;
 480                case '?':
 481                        if (optopt == 'n' || optopt == 'r' || optopt == 't')
 482                                fprintf(stderr,
 483                                        "Option -%c requires an argument.\n\n",
 484                                        optopt);
 485                case 'h':
 486                        // fallthrough
 487                default:
 488                        Usage();
 489                        return 0;
 490                }
 491        }
 492
 493        if (optind < argc)
 494                prog = argv[optind];
 495        printf("HBM prog: %s\n", prog != NULL ? prog : "NULL");
 496
 497        return run_bpf_prog(prog, cg_id);
 498}
 499