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