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
explain(void)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
choke_parse_opt(struct qdisc_util * qu,int argc,char ** argv,struct nlmsghdr * n)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
choke_print_opt(struct qdisc_util * qu,FILE * f,struct rtattr * opt)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
choke_print_xstats(struct qdisc_util * qu,FILE * f,struct rtattr * xstats)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 };
228