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 bool edt_flag;
  66
  67 static void Usage(void);
  68 static void read_trace_pipe2(void);
  69 static void do_error(char *msg, bool errno_flag);
  70
  71 #define DEBUGFS "/sys/kernel/debug/tracing/"
  72
  73 struct bpf_object *obj;
  74 int bpfprog_fd;
  75 int cgroup_storage_fd;
  76
  77 static 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
 113 static 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
 122 static 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
 160 static 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;
 398 err:
 399         rc = 1;
 400
 401         if (cg1)
 402                 close(cg1);
 403         cleanup_cgroup_environment();
 404
 405         return rc;
 406 }
 407
 408 static 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
 435 int 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 }