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