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 (at) 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 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 (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 max_P = probability * pow(2, 32); 160 addattr_l(n, 1024, TCA_CHOKE_MAX_P, &max_P, sizeof(max_P)); 161 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail; 162 return 0; 163 } 164 165 static int choke_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt) 166 { 167 struct rtattr *tb[TCA_CHOKE_MAX+1]; 168 const struct tc_red_qopt *qopt; 169 __u32 max_P = 0; 170 171 if (opt == NULL) 172 return 0; 173 174 parse_rtattr_nested(tb, TCA_CHOKE_MAX, opt); 175 176 if (tb[TCA_CHOKE_PARMS] == NULL) 177 return -1; 178 qopt = RTA_DATA(tb[TCA_CHOKE_PARMS]); 179 if (RTA_PAYLOAD(tb[TCA_CHOKE_PARMS]) < sizeof(*qopt)) 180 return -1; 181 if (tb[TCA_CHOKE_MAX_P] && 182 RTA_PAYLOAD(tb[TCA_CHOKE_MAX_P]) >= sizeof(__u32)) 183 max_P = rta_getattr_u32(tb[TCA_CHOKE_MAX_P]); 184 185 fprintf(f, "limit %up min %up max %up ", 186 qopt->limit, qopt->qth_min, qopt->qth_max); 187 188 if (qopt->flags & TC_RED_ECN) 189 fprintf(f, "ecn "); 190 191 if (show_details) { 192 fprintf(f, "ewma %u ", qopt->Wlog); 193 if (max_P) 194 fprintf(f, "probability %g ", max_P / pow(2, 32)); 195 else 196 fprintf(f, "Plog %u ", qopt->Plog); 197 fprintf(f, "Scell_log %u", qopt->Scell_log); 198 } 199 return 0; 200 } 201 202 static int choke_print_xstats(struct qdisc_util *qu, FILE *f, 203 struct rtattr *xstats) 204 { 205 struct tc_choke_xstats *st; 206 207 if (xstats == NULL) 208 return 0; 209 210 if (RTA_PAYLOAD(xstats) < sizeof(*st)) 211 return -1; 212 213 st = RTA_DATA(xstats); 214 fprintf(f, " marked %u early %u pdrop %u other %u matched %u", 215 st->marked, st->early, st->pdrop, st->other, st->matched); 216 return 0; 217 218 } 219 220 struct qdisc_util choke_qdisc_util = { 221 .id = "choke", 222 .parse_qopt = choke_parse_opt, 223 .print_qopt = choke_print_opt, 224 .print_xstats = choke_print_xstats, 225 }; 226
