tc/q_choke.c

   1 /*
   2  * q_choke.c            CHOKE.
   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@vyatta.com>
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15 #include <fcntl.h>
  16 #include <sys/socket.h>
  17 #include <netinet/in.h>
  18 #include <arpa/inet.h>
  19 #include <string.h>
  20 #include <math.h>
  21
  22 #include "utils.h"
  23 #include "tc_util.h"
  24
  25 #include "tc_red.h"
  26
  27 static void explain(void)
  28 {
  29         fprintf(stderr,
  30                 "Usage: ... choke limit PACKETS bandwidth KBPS [ecn]\n"
  31                 "                [ min PACKETS ] [ max PACKETS ] [ burst PACKETS ]\n");
  32 }
  33
  34 static int choke_parse_opt(struct qdisc_util *qu, int argc, char **argv,
  35                            struct nlmsghdr *n, const char *dev)
  36 {
  37         struct tc_red_qopt opt = {};
  38         unsigned int burst = 0;
  39         unsigned int avpkt = 1000;
  40         double probability = 0.02;
  41         unsigned int rate = 0;
  42         int ecn_ok = 0;
  43         int wlog;
  44         __u8 sbuf[256];
  45         __u32 max_P;
  46         struct rtattr *tail;
  47
  48         while (argc > 0) {
  49                 if (strcmp(*argv, "limit") == 0) {
  50                         NEXT_ARG();
  51                         if (get_unsigned(&opt.limit, *argv, 0)) {
  52                                 fprintf(stderr, "Illegal \"limit\"\n");
  53                                 return -1;
  54                         }
  55                 } else if (strcmp(*argv, "bandwidth") == 0) {
  56                         NEXT_ARG();
  57                         if (strchr(*argv, '%')) {
  58                                 if (get_percent_rate(&rate, *argv, dev)) {
  59                                         fprintf(stderr, "Illegal \"bandwidth\"\n");
  60                                         return -1;
  61                                 }
  62                         } else if (get_rate(&rate, *argv)) {
  63                                 fprintf(stderr, "Illegal \"bandwidth\"\n");
  64                                 return -1;
  65                         }
  66                 } else if (strcmp(*argv, "ecn") == 0) {
  67                         ecn_ok = 1;
  68                 } else if (strcmp(*argv, "min") == 0) {
  69                         NEXT_ARG();
  70                         if (get_unsigned(&opt.qth_min, *argv, 0)) {
  71                                 fprintf(stderr, "Illegal \"min\"\n");
  72                                 return -1;
  73                         }
  74                 } else if (strcmp(*argv, "max") == 0) {
  75                         NEXT_ARG();
  76                         if (get_unsigned(&opt.qth_max, *argv, 0)) {
  77                                 fprintf(stderr, "Illegal \"max\"\n");
  78                                 return -1;
  79                         }
  80                 } else if (strcmp(*argv, "burst") == 0) {
  81                         NEXT_ARG();
  82                         if (get_unsigned(&burst, *argv, 0)) {
  83                                 fprintf(stderr, "Illegal \"burst\"\n");
  84                                 return -1;
  85                         }
  86                 } else if (strcmp(*argv, "avpkt") == 0) {
  87                         NEXT_ARG();
  88                         if (get_size(&avpkt, *argv)) {
  89                                 fprintf(stderr, "Illegal \"avpkt\"\n");
  90                                 return -1;
  91                         }
  92                 } else if (strcmp(*argv, "probability") == 0) {
  93                         NEXT_ARG();
  94                         if (sscanf(*argv, "%lg", &probability) != 1) {
  95                                 fprintf(stderr, "Illegal \"probability\"\n");
  96                                 return -1;
  97                         }
  98                 } else if (strcmp(*argv, "help") == 0) {
  99                         explain();
 100                         return -1;
 101                 } else {
 102                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 103                         explain();
 104                         return -1;
 105                 }
 106                 argc--; argv++;
 107         }
 108
 109         if (!rate || !opt.limit) {
 110                 fprintf(stderr, "Required parameter (bandwidth, limit) is missing\n");
 111                 return -1;
 112         }
 113
 114         /* Compute default min/max thresholds based on
 115            Sally Floyd's recommendations:
 116            http://www.icir.org/floyd/REDparameters.txt
 117         */
 118         if (!opt.qth_max)
 119                 opt.qth_max = opt.limit / 4;
 120         if (!opt.qth_min)
 121                 opt.qth_min = opt.qth_max / 3;
 122         if (!burst)
 123                 burst = (2 * opt.qth_min + opt.qth_max) / 3;
 124
 125         if (opt.qth_max > opt.limit) {
 126                 fprintf(stderr, "\"max\" is larger than \"limit\"\n");
 127                 return -1;
 128         }
 129
 130         if (opt.qth_min >= opt.qth_max) {
 131                 fprintf(stderr, "\"min\" is not smaller than \"max\"\n");
 132                 return -1;
 133         }
 134
 135         wlog = tc_red_eval_ewma(opt.qth_min*avpkt, burst, avpkt);
 136         if (wlog < 0) {
 137                 fprintf(stderr, "CHOKE: failed to calculate EWMA constant.\n");
 138                 return -1;
 139         }
 140         if (wlog >= 10)
 141                 fprintf(stderr, "CHOKE: WARNING. Burst %d seems to be too large.\n", burst);
 142         opt.Wlog = wlog;
 143
 144         wlog = tc_red_eval_P(opt.qth_min*avpkt, opt.qth_max*avpkt, probability);
 145         if (wlog < 0) {
 146                 fprintf(stderr, "CHOKE: failed to calculate probability.\n");
 147                 return -1;
 148         }
 149         opt.Plog = wlog;
 150
 151         wlog = tc_red_eval_idle_damping(opt.Wlog, avpkt, rate, sbuf);
 152         if (wlog < 0) {
 153                 fprintf(stderr, "CHOKE: failed to calculate idle damping table.\n");
 154                 return -1;
 155         }
 156         opt.Scell_log = wlog;
 157         if (ecn_ok)
 158                 opt.flags |= TC_RED_ECN;
 159
 160         tail = addattr_nest(n, 1024, TCA_OPTIONS);
 161         addattr_l(n, 1024, TCA_CHOKE_PARMS, &opt, sizeof(opt));
 162         addattr_l(n, 1024, TCA_CHOKE_STAB, sbuf, 256);
 163         max_P = probability * pow(2, 32);
 164         addattr_l(n, 1024, TCA_CHOKE_MAX_P, &max_P, sizeof(max_P));
 165         addattr_nest_end(n, tail);
 166         return 0;
 167 }
 168
 169 static int choke_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 170 {
 171         struct rtattr *tb[TCA_CHOKE_MAX+1];
 172         const struct tc_red_qopt *qopt;
 173         __u32 max_P = 0;
 174
 175         if (opt == NULL)
 176                 return 0;
 177
 178         parse_rtattr_nested(tb, TCA_CHOKE_MAX, opt);
 179
 180         if (tb[TCA_CHOKE_PARMS] == NULL)
 181                 return -1;
 182         qopt = RTA_DATA(tb[TCA_CHOKE_PARMS]);
 183         if (RTA_PAYLOAD(tb[TCA_CHOKE_PARMS])  < sizeof(*qopt))
 184                 return -1;
 185         if (tb[TCA_CHOKE_MAX_P] &&
 186             RTA_PAYLOAD(tb[TCA_CHOKE_MAX_P]) >= sizeof(__u32))
 187                 max_P = rta_getattr_u32(tb[TCA_CHOKE_MAX_P]);
 188
 189         print_uint(PRINT_ANY, "limit", "limit %up ", qopt->limit);
 190         print_uint(PRINT_ANY, "min", "min %up ", qopt->qth_min);
 191         print_uint(PRINT_ANY, "max", "max %up ", qopt->qth_max);
 192
 193         tc_red_print_flags(qopt->flags);
 194
 195         if (show_details) {
 196                 print_uint(PRINT_ANY, "ewma", "ewma %u ", qopt->Wlog);
 197
 198                 if (max_P)
 199                         print_float(PRINT_ANY, "probability",
 200                                     "probability %lg ", max_P / pow(2, 32));
 201                 else
 202                         print_uint(PRINT_ANY, "Plog", "Plog %u ", qopt->Plog);
 203
 204                 print_uint(PRINT_ANY, "Scell_log", "Scell_log %u",
 205                            qopt->Scell_log);
 206         }
 207         return 0;
 208 }
 209
 210 static int choke_print_xstats(struct qdisc_util *qu, FILE *f,
 211                               struct rtattr *xstats)
 212 {
 213         struct tc_choke_xstats *st;
 214
 215         if (xstats == NULL)
 216                 return 0;
 217
 218         if (RTA_PAYLOAD(xstats) < sizeof(*st))
 219                 return -1;
 220
 221         st = RTA_DATA(xstats);
 222
 223         print_uint(PRINT_ANY, "marked", "  marked %u", st->marked);
 224         print_uint(PRINT_ANY, "early", " early %u", st->early);
 225         print_uint(PRINT_ANY, "pdrop", " pdrop %u", st->pdrop);
 226         print_uint(PRINT_ANY, "other", " other %u", st->other);
 227         print_uint(PRINT_ANY, "matched", " matched %u", st->matched);
 228
 229         return 0;
 230
 231 }
 232
 233 struct qdisc_util choke_qdisc_util = {
 234         .id             = "choke",
 235         .parse_qopt     = choke_parse_opt,
 236         .print_qopt     = choke_print_opt,
 237         .print_xstats   = choke_print_xstats,
 238 };