tc/q_netem.c

   1 /*
   2  * q_netem.c            NETEM.
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Stephen Hemminger <shemminger@osdl.org>
  10  *
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <syslog.h>
  17 #include <fcntl.h>
  18 #include <sys/socket.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21 #include <string.h>
  22 #include <errno.h>
  23
  24 #include "utils.h"
  25 #include "tc_util.h"
  26 #include "tc_common.h"
  27
  28 static void explain(void)
  29 {
  30         fprintf(stderr,
  31 "Usage: ... netem [ limit PACKETS ] \n" \
  32 "                 [ delay TIME [ JITTER [CORRELATION]]]\n" \
  33 "                 [ distribution {uniform|normal|pareto|paretonormal} ]\n" \
  34 "                 [ drop PERCENT [CORRELATION]] \n" \
  35 "                 [ corrupt PERCENT [CORRELATION]] \n" \
  36 "                 [ duplicate PERCENT [CORRELATION]]\n" \
  37 "                 [ reorder PRECENT [CORRELATION] [ gap DISTANCE ]]\n");
  38 }
  39
  40 static void explain1(const char *arg)
  41 {
  42         fprintf(stderr, "Illegal \"%s\"\n", arg);
  43 }
  44
  45 #define usage() return(-1)
  46
  47 /*
  48  * Simplistic file parser for distrbution data.
  49  * Format is:
  50  *      # comment line(s)
  51  *      data0 data1
  52  */
  53 #define MAXDIST 65536
  54 static int get_distribution(const char *type, __s16 *data)
  55 {
  56         FILE *f;
  57         int n;
  58         long x;
  59         size_t len;
  60         char *line = NULL;
  61         char name[128];
  62
  63         snprintf(name, sizeof(name), "/usr/lib/tc/%s.dist", type);
  64         if ((f = fopen(name, "r")) == NULL) {
  65                 fprintf(stderr, "No distribution data for %s (%s: %s)\n",
  66                         type, name, strerror(errno));
  67                 return -1;
  68         }
  69
  70         n = 0;
  71         while (getline(&line, &len, f) != -1) {
  72                 char *p, *endp;
  73                 if (*line == '\n' || *line == '#')
  74                         continue;
  75
  76                 for (p = line; ; p = endp) {
  77                         x = strtol(p, &endp, 0);
  78                         if (endp == p)
  79                                 break;
  80
  81                         if (n >= MAXDIST) {
  82                                 fprintf(stderr, "%s: too much data\n",
  83                                         name);
  84                                 n = -1;
  85                                 goto error;
  86                         }
  87                         data[n++] = x;
  88                 }
  89         }
  90  error:
  91         free(line);
  92         fclose(f);
  93         return n;
  94 }
  95
  96 static int isnumber(const char *arg)
  97 {
  98         char *p;
  99         (void) strtod(arg, &p);
 100         return (p != arg);
 101 }
 102
 103 #define NEXT_IS_NUMBER() (NEXT_ARG_OK() && isnumber(argv[1]))
 104
 105 /* Adjust for the fact that psched_ticks aren't always usecs
 106    (based on kernel PSCHED_CLOCK configuration */
 107 static int get_ticks(__u32 *ticks, const char *str)
 108 {
 109         unsigned t;
 110
 111         if(get_usecs(&t, str))
 112                 return -1;
 113
 114         *ticks = tc_core_usec2tick(t);
 115         return 0;
 116 }
 117
 118 static char *sprint_ticks(__u32 ticks, char *buf)
 119 {
 120         return sprint_usecs(tc_core_tick2usec(ticks), buf);
 121 }
 122
 123
 124 static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 125                            struct nlmsghdr *n)
 126 {
 127         size_t dist_size = 0;
 128         struct rtattr *tail;
 129         struct tc_netem_qopt opt;
 130         struct tc_netem_corr cor;
 131         struct tc_netem_reorder reorder;
 132         struct tc_netem_corrupt corrupt;
 133         __s16 *dist_data = NULL;
 134
 135         memset(&opt, 0, sizeof(opt));
 136         opt.limit = 1000;
 137         memset(&cor, 0, sizeof(cor));
 138         memset(&reorder, 0, sizeof(reorder));
 139         memset(&corrupt, 0, sizeof(corrupt));
 140
 141         while (argc > 0) {
 142                 if (matches(*argv, "limit") == 0) {
 143                         NEXT_ARG();
 144                         if (get_size(&opt.limit, *argv)) {
 145                                 explain1("limit");
 146                                 return -1;
 147                         }
 148                 } else if (matches(*argv, "latency") == 0 ||
 149                            matches(*argv, "delay") == 0) {
 150                         NEXT_ARG();
 151                         if (get_ticks(&opt.latency, *argv)) {
 152                                 explain1("latency");
 153                                 return -1;
 154                         }
 155
 156                         if (NEXT_IS_NUMBER()) {
 157                                 NEXT_ARG();
 158                                 if (get_ticks(&opt.jitter, *argv)) {
 159                                         explain1("latency");
 160                                         return -1;
 161                                 }
 162
 163                                 if (NEXT_IS_NUMBER()) {
 164                                         NEXT_ARG();
 165                                         if (get_percent(&cor.delay_corr,
 166                                                         *argv)) {
 167                                                 explain1("latency");
 168                                                 return -1;
 169                                         }
 170                                 }
 171                         }
 172                 } else if (matches(*argv, "loss") == 0 ||
 173                            matches(*argv, "drop") == 0) {
 174                         NEXT_ARG();
 175                         if (get_percent(&opt.loss, *argv)) {
 176                                 explain1("loss");
 177                                 return -1;
 178                         }
 179                         if (NEXT_IS_NUMBER()) {
 180                                 NEXT_ARG();
 181                                 if (get_percent(&cor.loss_corr, *argv)) {
 182                                         explain1("loss");
 183                                         return -1;
 184                                 }
 185                         }
 186                 } else if (matches(*argv, "reorder") == 0) {
 187                         NEXT_ARG();
 188                         if (get_percent(&reorder.probability, *argv)) {
 189                                 explain1("reorder");
 190                                 return -1;
 191                         }
 192                         if (NEXT_IS_NUMBER()) {
 193                                 NEXT_ARG();
 194                                 if (get_percent(&reorder.correlation, *argv)) {
 195                                         explain1("reorder");
 196                                         return -1;
 197                                 }
 198                         }
 199                 } else if (matches(*argv, "corrupt") == 0) {
 200                         NEXT_ARG();
 201                         if (get_percent(&corrupt.probability, *argv)) {
 202                                 explain1("corrupt");
 203                                 return -1;
 204                         }
 205                         if (NEXT_IS_NUMBER()) {
 206                                 NEXT_ARG();
 207                                 if (get_percent(&corrupt.correlation, *argv)) {
 208                                         explain1("corrupt");
 209                                         return -1;
 210                                 }
 211                         }
 212                 } else if (matches(*argv, "gap") == 0) {
 213                         NEXT_ARG();
 214                         if (get_u32(&opt.gap, *argv, 0)) {
 215                                 explain1("gap");
 216                                 return -1;
 217                         }
 218                 } else if (matches(*argv, "duplicate") == 0) {
 219                         NEXT_ARG();
 220                         if (get_percent(&opt.duplicate, *argv)) {
 221                                 explain1("duplicate");
 222                                 return -1;
 223                         }
 224                         if (NEXT_IS_NUMBER()) {
 225                                 NEXT_ARG();
 226                                 if (get_percent(&cor.dup_corr, *argv)) {
 227                                         explain1("duplicate");
 228                                         return -1;
 229                                 }
 230                         }
 231                 } else if (matches(*argv, "distribution") == 0) {
 232                         NEXT_ARG();
 233                         dist_data = alloca(MAXDIST);
 234                         dist_size = get_distribution(*argv, dist_data);
 235                         if (dist_size < 0)
 236                                 return -1;
 237                 } else if (strcmp(*argv, "help") == 0) {
 238                         explain();
 239                         return -1;
 240                 } else {
 241                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 242                         explain();
 243                         return -1;
 244                 }
 245                 argc--; argv++;
 246         }
 247
 248         tail = NLMSG_TAIL(n);
 249
 250         if (reorder.probability) {
 251                 if (opt.latency == 0) {
 252                         fprintf(stderr, "reordering not possible without specifying some delay\n");
 253                 }
 254                 if (opt.gap == 0)
 255                         opt.gap = 1;
 256         } else if (opt.gap > 0) {
 257                 fprintf(stderr, "gap specified without reorder probability\n");
 258                 explain();
 259                 return -1;
 260         }
 261
 262         if (dist_data && (opt.latency == 0 || opt.jitter == 0)) {
 263                 fprintf(stderr, "distribution specified but no latency and jitter values\n");
 264                 explain();
 265                 return -1;
 266         }
 267
 268         if (addattr_l(n, TCA_BUF_MAX, TCA_OPTIONS, &opt, sizeof(opt)) < 0)
 269                 return -1;
 270
 271         if (cor.delay_corr || cor.loss_corr || cor.dup_corr) {
 272                 if (addattr_l(n, TCA_BUF_MAX, TCA_NETEM_CORR, &cor, sizeof(cor)) < 0)
 273                         return -1;
 274         }
 275
 276         if (addattr_l(n, TCA_BUF_MAX, TCA_NETEM_REORDER, &reorder, sizeof(reorder)) < 0)
 277                 return -1;
 278
 279         if (corrupt.probability) {
 280                 if (addattr_l(n, TCA_BUF_MAX, TCA_NETEM_CORRUPT, &corrupt, sizeof(corrupt)) < 0)
 281                         return -1;
 282         }
 283
 284         if (dist_data) {
 285                 if (addattr_l(n, 32768, TCA_NETEM_DELAY_DIST,
 286                               dist_data, dist_size*sizeof(dist_data[0])) < 0)
 287                         return -1;
 288         }
 289         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 290         return 0;
 291 }
 292
 293 static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 294 {
 295         const struct tc_netem_corr *cor = NULL;
 296         const struct tc_netem_reorder *reorder = NULL;
 297         const struct tc_netem_corrupt *corrupt = NULL;
 298         struct tc_netem_qopt qopt;
 299         int len = RTA_PAYLOAD(opt) - sizeof(qopt);
 300         SPRINT_BUF(b1);
 301
 302         if (opt == NULL)
 303                 return 0;
 304
 305         if (len < 0) {
 306                 fprintf(stderr, "options size error\n");
 307                 return -1;
 308         }
 309         memcpy(&qopt, RTA_DATA(opt), sizeof(qopt));
 310
 311         if (len > 0) {
 312                 struct rtattr *tb[TCA_NETEM_MAX+1];
 313                 parse_rtattr(tb, TCA_NETEM_MAX, RTA_DATA(opt) + sizeof(qopt),
 314                              len);
 315
 316                 if (tb[TCA_NETEM_CORR]) {
 317                         if (RTA_PAYLOAD(tb[TCA_NETEM_CORR]) < sizeof(*cor))
 318                                 return -1;
 319                         cor = RTA_DATA(tb[TCA_NETEM_CORR]);
 320                 }
 321                 if (tb[TCA_NETEM_REORDER]) {
 322                         if (RTA_PAYLOAD(tb[TCA_NETEM_REORDER]) < sizeof(*reorder))
 323                                 return -1;
 324                         reorder = RTA_DATA(tb[TCA_NETEM_REORDER]);
 325                 }
 326                 if (tb[TCA_NETEM_CORRUPT]) {
 327                         if (RTA_PAYLOAD(tb[TCA_NETEM_CORRUPT]) < sizeof(*corrupt))
 328                                 return -1;
 329                         corrupt = RTA_DATA(tb[TCA_NETEM_CORRUPT]);
 330                 }
 331         }
 332
 333         fprintf(f, "limit %d", qopt.limit);
 334
 335         if (qopt.latency) {
 336                 fprintf(f, " delay %s", sprint_ticks(qopt.latency, b1));
 337
 338                 if (qopt.jitter) {
 339                         fprintf(f, "  %s", sprint_ticks(qopt.jitter, b1));
 340                         if (cor && cor->delay_corr)
 341                                 fprintf(f, " %s", sprint_percent(cor->delay_corr, b1));
 342                 }
 343         }
 344
 345         if (qopt.loss) {
 346                 fprintf(f, " loss %s", sprint_percent(qopt.loss, b1));
 347                 if (cor && cor->loss_corr)
 348                         fprintf(f, " %s", sprint_percent(cor->loss_corr, b1));
 349         }
 350
 351         if (qopt.duplicate) {
 352                 fprintf(f, " duplicate %s",
 353                         sprint_percent(qopt.duplicate, b1));
 354                 if (cor && cor->dup_corr)
 355                         fprintf(f, " %s", sprint_percent(cor->dup_corr, b1));
 356         }
 357
 358         if (reorder && reorder->probability) {
 359                 fprintf(f, " reorder %s",
 360                         sprint_percent(reorder->probability, b1));
 361                 if (reorder->correlation)
 362                         fprintf(f, " %s",
 363                                 sprint_percent(reorder->correlation, b1));
 364         }
 365
 366         if (corrupt && corrupt->probability) {
 367                 fprintf(f, " corrupt %s",
 368                         sprint_percent(corrupt->probability, b1));
 369                 if (corrupt->correlation)
 370                         fprintf(f, " %s",
 371                                 sprint_percent(corrupt->correlation, b1));
 372         }
 373
 374         if (qopt.gap)
 375                 fprintf(f, " gap %lu", (unsigned long)qopt.gap);
 376
 377         return 0;
 378 }
 379
 380 struct qdisc_util netem_qdisc_util = {
 381         .id             = "netem",
 382         .parse_qopt     = netem_parse_opt,
 383         .print_qopt     = netem_print_opt,
 384 };
 385