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 "                 [ drop PERCENT [CORRELATION]] \n" \
  34 "                 [ duplicate PERCENT [CORRELATION]]\n" \
  35 "                 [ distribution {uniform|normal|pareto|paretonormal} ]\n" \
  36 "                 [ gap PACKETS ]\n");
  37 }
  38
  39 static void explain1(const char *arg)
  40 {
  41         fprintf(stderr, "Illegal \"%s\"\n", arg);
  42 }
  43
  44 #define usage() return(-1)
  45
  46 /*
  47  * Simplistic file parser for distrbution data.
  48  * Format is:
  49  *      # comment line(s)
  50  *      data0 data1
  51  */
  52 #define MAXDIST 65536
  53 static int get_distribution(const char *type, __s16 *data)
  54 {
  55         FILE *f;
  56         int n;
  57         long x;
  58         size_t len;
  59         char *line = NULL;
  60         char name[128];
  61
  62         snprintf(name, sizeof(name), "/usr/lib/tc/%s.dist", type);
  63         if ((f = fopen(name, "r")) == NULL) {
  64                 fprintf(stderr, "No distribution data for %s (%s: %s)\n",
  65                         type, name, strerror(errno));
  66                 return -1;
  67         }
  68
  69         n = 0;
  70         while (getline(&line, &len, f) != -1) {
  71                 char *p, *endp;
  72                 if (*line == '\n' || *line == '#')
  73                         continue;
  74
  75                 for (p = line; ; p = endp) {
  76                         x = strtol(p, &endp, 0);
  77                         if (endp == p)
  78                                 break;
  79
  80                         if (n >= MAXDIST) {
  81                                 fprintf(stderr, "%s: too much data\n",
  82                                         name);
  83                                 n = -1;
  84                                 goto error;
  85                         }
  86                         data[n++] = x;
  87                 }
  88         }
  89  error:
  90         free(line);
  91         fclose(f);
  92         return n;
  93 }
  94
  95 static int isnumber(const char *arg)
  96 {
  97         char *p;
  98         (void) strtod(arg, &p);
  99         return (p != arg);
 100 }
 101
 102 #define NEXT_IS_NUMBER() (NEXT_ARG_OK() && isnumber(argv[1]))
 103
 104 /* Adjust for the fact that psched_ticks aren't always usecs
 105    (based on kernel PSCHED_CLOCK configuration */
 106 static int get_ticks(__u32 *ticks, const char *str)
 107 {
 108         unsigned t;
 109
 110         if(get_usecs(&t, str))
 111                 return -1;
 112
 113         *ticks = tc_core_usec2tick(t);
 114         return 0;
 115 }
 116
 117 static char *sprint_ticks(__u32 ticks, char *buf)
 118 {
 119         return sprint_usecs(tc_core_tick2usec(ticks), buf);
 120 }
 121
 122
 123 static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
 124                            struct nlmsghdr *n)
 125 {
 126         size_t dist_size = 0;
 127         struct rtattr *tail;
 128         struct tc_netem_qopt opt;
 129         struct tc_netem_corr cor;
 130         __s16 dist_data[MAXDIST];
 131
 132         memset(&opt, 0, sizeof(opt));
 133         opt.limit = 1000;
 134         memset(&cor, 0, sizeof(cor));
 135
 136         while (argc > 0) {
 137                 if (matches(*argv, "limit") == 0) {
 138                         NEXT_ARG();
 139                         if (get_size(&opt.limit, *argv)) {
 140                                 explain1("limit");
 141                                 return -1;
 142                         }
 143                 } else if (matches(*argv, "latency") == 0 ||
 144                            matches(*argv, "delay") == 0) {
 145                         NEXT_ARG();
 146                         if (get_ticks(&opt.latency, *argv)) {
 147                                 explain1("latency");
 148                                 return -1;
 149                         }
 150
 151                         if (NEXT_IS_NUMBER()) {
 152                                 NEXT_ARG();
 153                                 if (get_ticks(&opt.jitter, *argv)) {
 154                                         explain1("latency");
 155                                         return -1;
 156                                 }
 157
 158                                 if (NEXT_IS_NUMBER()) {
 159                                         NEXT_ARG();
 160                                         if (get_percent(&cor.delay_corr,
 161                                                         *argv)) {
 162                                                 explain1("latency");
 163                                                 return -1;
 164                                         }
 165                                 }
 166                         }
 167                 } else if (matches(*argv, "loss") == 0 ||
 168                            matches(*argv, "drop") == 0) {
 169                         NEXT_ARG();
 170                         if (get_percent(&opt.loss, *argv)) {
 171                                 explain1("loss");
 172                                 return -1;
 173                         }
 174                         if (NEXT_IS_NUMBER()) {
 175                                 NEXT_ARG();
 176                                 if (get_percent(&cor.loss_corr, *argv)) {
 177                                         explain1("loss");
 178                                         return -1;
 179                                 }
 180                         }
 181                 } else if (matches(*argv, "gap") == 0) {
 182                         NEXT_ARG();
 183                         if (get_u32(&opt.gap, *argv, 0)) {
 184                                 explain1("gap");
 185                                 return -1;
 186                         }
 187                 } else if (matches(*argv, "duplicate") == 0) {
 188                         NEXT_ARG();
 189                         if (get_percent(&opt.duplicate, *argv)) {
 190                                 explain1("duplicate");
 191                                 return -1;
 192                         }
 193                         if (NEXT_IS_NUMBER()) {
 194                                 NEXT_ARG();
 195                                 if (get_percent(&cor.dup_corr, *argv)) {
 196                                         explain1("duplicate");
 197                                         return -1;
 198                                 }
 199                         }
 200                 } else if (matches(*argv, "distribution") == 0) {
 201                         NEXT_ARG();
 202                         dist_size = get_distribution(*argv, dist_data);
 203                         if (dist_size < 0)
 204                                 return -1;
 205                 } else if (strcmp(*argv, "help") == 0) {
 206                         explain();
 207                         return -1;
 208                 } else {
 209                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 210                         explain();
 211                         return -1;
 212                 }
 213                 argc--; argv++;
 214         }
 215
 216         tail = NLMSG_TAIL(n);
 217
 218         addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));
 219         addattr_l(n, 1024, TCA_NETEM_CORR, &cor, sizeof(cor));
 220
 221         if (dist_size > 0) {
 222                 addattr_l(n, 32768, TCA_NETEM_DELAY_DIST,
 223                           dist_data, dist_size*sizeof(dist_data[0]));
 224         }
 225         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 226         return 0;
 227 }
 228
 229 static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 230 {
 231         const struct tc_netem_corr *cor = NULL;
 232         struct tc_netem_qopt qopt;
 233         int len = RTA_PAYLOAD(opt) - sizeof(qopt);
 234         SPRINT_BUF(b1);
 235
 236         if (opt == NULL)
 237                 return 0;
 238
 239         if (len < 0) {
 240                 fprintf(stderr, "options size error\n");
 241                 return -1;
 242         }
 243         memcpy(&qopt, RTA_DATA(opt), sizeof(qopt));
 244
 245         if (len > 0) {
 246                 struct rtattr *tb[TCA_NETEM_MAX+1];
 247                 parse_rtattr(tb, TCA_NETEM_MAX, RTA_DATA(opt) + sizeof(qopt),
 248                              len);
 249
 250                 if (tb[TCA_NETEM_CORR]) {
 251                         if (RTA_PAYLOAD(tb[TCA_NETEM_CORR]) < sizeof(*cor))
 252                                 return -1;
 253                         cor = RTA_DATA(tb[TCA_NETEM_CORR]);
 254                 }
 255         }
 256
 257         fprintf(f, "limit %d", qopt.limit);
 258
 259         if (qopt.latency) {
 260                 fprintf(f, " delay %s", sprint_ticks(qopt.latency, b1));
 261
 262                 if (qopt.jitter) {
 263                         fprintf(f, "  %s", sprint_ticks(qopt.jitter, b1));
 264                         if (cor && cor->delay_corr)
 265                                 fprintf(f, " %s", sprint_percent(cor->delay_corr, b1));
 266                 }
 267         }
 268
 269         if (qopt.loss) {
 270                 fprintf(f, " loss %s", sprint_percent(qopt.loss, b1));
 271                 if (cor && cor->loss_corr)
 272                         fprintf(f, " %s", sprint_percent(cor->loss_corr, b1));
 273         }
 274
 275         if (qopt.duplicate) {
 276                 fprintf(f, " duplicate %s",
 277                         sprint_percent(qopt.duplicate, b1));
 278                 if (cor && cor->dup_corr)
 279                         fprintf(f, " %s", sprint_percent(cor->dup_corr, b1));
 280         }
 281
 282         if (qopt.gap)
 283                 fprintf(f, " gap %lu", (unsigned long)qopt.gap);
 284
 285         return 0;
 286 }
 287
 288 struct qdisc_util netem_qdisc_util = {
 289         .id             = "netem",
 290         .parse_qopt     = netem_parse_opt,
 291         .print_qopt     = netem_print_opt,
 292 };
 293