tc/q_red.c

   1 /*
   2  * q_red.c              RED.
   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:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  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
  23 #include "utils.h"
  24 #include "tc_util.h"
  25
  26 #include "tc_red.h"
  27
  28 static void explain(void)
  29 {
  30         fprintf(stderr, "Usage: ... red limit BYTES [min BYTES] [max BYTES] avpkt BYTES [burst PACKETS]\n");
  31         fprintf(stderr, "               [probability PROBABILITY] bandwidth KBPS [ecn] [harddrop]\n");
  32 }
  33
  34 static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
  35 {
  36         struct tc_red_qopt opt;
  37         unsigned burst = 0;
  38         unsigned avpkt = 0;
  39         double probability = 0.02;
  40         unsigned rate = 0;
  41         int wlog;
  42         __u8 sbuf[256];
  43         struct rtattr *tail;
  44
  45         memset(&opt, 0, sizeof(opt));
  46
  47         while (argc > 0) {
  48                 if (strcmp(*argv, "limit") == 0) {
  49                         NEXT_ARG();
  50                         if (get_size(&opt.limit, *argv)) {
  51                                 fprintf(stderr, "Illegal \"limit\"\n");
  52                                 return -1;
  53                         }
  54                 } else if (strcmp(*argv, "min") == 0) {
  55                         NEXT_ARG();
  56                         if (get_size(&opt.qth_min, *argv)) {
  57                                 fprintf(stderr, "Illegal \"min\"\n");
  58                                 return -1;
  59                         }
  60                 } else if (strcmp(*argv, "max") == 0) {
  61                         NEXT_ARG();
  62                         if (get_size(&opt.qth_max, *argv)) {
  63                                 fprintf(stderr, "Illegal \"max\"\n");
  64                                 return -1;
  65                         }
  66                 } else if (strcmp(*argv, "burst") == 0) {
  67                         NEXT_ARG();
  68                         if (get_unsigned(&burst, *argv, 0)) {
  69                                 fprintf(stderr, "Illegal \"burst\"\n");
  70                                 return -1;
  71                         }
  72                 } else if (strcmp(*argv, "avpkt") == 0) {
  73                         NEXT_ARG();
  74                         if (get_size(&avpkt, *argv)) {
  75                                 fprintf(stderr, "Illegal \"avpkt\"\n");
  76                                 return -1;
  77                         }
  78                 } else if (strcmp(*argv, "probability") == 0) {
  79                         NEXT_ARG();
  80                         if (sscanf(*argv, "%lg", &probability) != 1) {
  81                                 fprintf(stderr, "Illegal \"probability\"\n");
  82                                 return -1;
  83                         }
  84                 } else if (strcmp(*argv, "bandwidth") == 0) {
  85                         NEXT_ARG();
  86                         if (get_rate(&rate, *argv)) {
  87                                 fprintf(stderr, "Illegal \"bandwidth\"\n");
  88                                 return -1;
  89                         }
  90                 } else if (strcmp(*argv, "ecn") == 0) {
  91                         opt.flags |= TC_RED_ECN;
  92                 } else if (strcmp(*argv, "harddrop") == 0) {
  93                         opt.flags |= TC_RED_HARDDROP;
  94                 } else if (strcmp(*argv, "help") == 0) {
  95                         explain();
  96                         return -1;
  97                 } else {
  98                         fprintf(stderr, "What is \"%s\"?\n", *argv);
  99                         explain();
 100                         return -1;
 101                 }
 102                 argc--; argv++;
 103         }
 104
 105         if (rate == 0)
 106                 get_rate(&rate, "10Mbit");
 107
 108         if (!opt.limit || !avpkt) {
 109                 fprintf(stderr, "RED: Required parameter (limit, avpkt) is missing\n");
 110                 return -1;
 111         }
 112         /* Compute default min/max thresholds based on
 113          * Sally Floyd's recommendations:
 114          * http://www.icir.org/floyd/REDparameters.txt
 115          */
 116         if (!opt.qth_max)
 117                 opt.qth_max = opt.qth_min ? opt.qth_min * 3 : opt.limit / 4;
 118         if (!opt.qth_min)
 119                 opt.qth_min = opt.qth_max / 3;
 120         if (!burst)
 121                 burst = (2 * opt.qth_min + opt.qth_max) / (3 * avpkt);
 122         if ((wlog = tc_red_eval_ewma(opt.qth_min, burst, avpkt)) < 0) {
 123                 fprintf(stderr, "RED: failed to calculate EWMA constant.\n");
 124                 return -1;
 125         }
 126         if (wlog >= 10)
 127                 fprintf(stderr, "RED: WARNING. Burst %d seems to be too large.\n", burst);
 128         opt.Wlog = wlog;
 129         if ((wlog = tc_red_eval_P(opt.qth_min, opt.qth_max, probability)) < 0) {
 130                 fprintf(stderr, "RED: failed to calculate probability.\n");
 131                 return -1;
 132         }
 133         opt.Plog = wlog;
 134         if ((wlog = tc_red_eval_idle_damping(opt.Wlog, avpkt, rate, sbuf)) < 0) {
 135                 fprintf(stderr, "RED: failed to calculate idle damping table.\n");
 136                 return -1;
 137         }
 138         opt.Scell_log = wlog;
 139
 140         tail = NLMSG_TAIL(n);
 141         addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
 142         addattr_l(n, 1024, TCA_RED_PARMS, &opt, sizeof(opt));
 143         addattr_l(n, 1024, TCA_RED_STAB, sbuf, 256);
 144         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 145         return 0;
 146 }
 147
 148 static int red_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 149 {
 150         struct rtattr *tb[TCA_RED_MAX + 1];
 151         struct tc_red_qopt *qopt;
 152         SPRINT_BUF(b1);
 153         SPRINT_BUF(b2);
 154         SPRINT_BUF(b3);
 155
 156         if (opt == NULL)
 157                 return 0;
 158
 159         parse_rtattr_nested(tb, TCA_RED_MAX, opt);
 160
 161         if (tb[TCA_RED_PARMS] == NULL)
 162                 return -1;
 163         qopt = RTA_DATA(tb[TCA_RED_PARMS]);
 164         if (RTA_PAYLOAD(tb[TCA_RED_PARMS])  < sizeof(*qopt))
 165                 return -1;
 166         fprintf(f, "limit %s min %s max %s ",
 167                 sprint_size(qopt->limit, b1),
 168                 sprint_size(qopt->qth_min, b2),
 169                 sprint_size(qopt->qth_max, b3));
 170         if (qopt->flags & TC_RED_ECN)
 171                 fprintf(f, "ecn ");
 172         if (qopt->flags & TC_RED_HARDDROP)
 173                 fprintf(f, "harddrop ");
 174         if (show_details) {
 175                 fprintf(f, "ewma %u Plog %u Scell_log %u",
 176                         qopt->Wlog, qopt->Plog, qopt->Scell_log);
 177         }
 178         return 0;
 179 }
 180
 181 static int red_print_xstats(struct qdisc_util *qu, FILE *f, struct rtattr *xstats)
 182 {
 183 #ifdef TC_RED_ECN
 184         struct tc_red_xstats *st;
 185
 186         if (xstats == NULL)
 187                 return 0;
 188
 189         if (RTA_PAYLOAD(xstats) < sizeof(*st))
 190                 return -1;
 191
 192         st = RTA_DATA(xstats);
 193         fprintf(f, "  marked %u early %u pdrop %u other %u",
 194                 st->marked, st->early, st->pdrop, st->other);
 195         return 0;
 196
 197 #endif
 198         return 0;
 199 }
 200
 201
 202 struct qdisc_util red_qdisc_util = {
 203         .id             = "red",
 204         .parse_qopt     = red_parse_opt,
 205         .print_qopt     = red_print_opt,
 206         .print_xstats   = red_print_xstats,
 207 };