xref: /illumos-gate/usr/src/uts/common/ipp/meters/tswtcl.c (revision 1a5e258f5471356ca102c7176637cdce45bac147)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/kmem.h>
29 #include <sys/random.h>
30 #include <netinet/in.h>
31 #include <netinet/in_systm.h>
32 #include <netinet/ip6.h>
33 #include <inet/common.h>
34 #include <inet/ip.h>
35 #include <inet/ip6.h>
36 #include <ipp/meters/meter_impl.h>
37 
38 /*
39  * Module : Time Sliding Window meter - tswtclmtr
40  * Description
41  * This module implements the metering part of RFC 2859. It accepts the
42  * committed rate, peak rate and the window for a flow and determines
43  * if the flow is within the committed/peak rate and assigns the appropriate
44  * next action.
45  * The meter provides an estimate of the running average bandwidth for the
46  * flow over the specified window. It uses probability to benefit TCP flows
47  * as it reduces the likelihood of dropping multiple packets within a TCP
48  * window without adversely effecting UDP flows.
49  */
50 
51 int tswtcl_debug = 0;
52 
53 /*
54  * Given a packet and the tswtcl_data it belongs to, this routine meters the
55  * ToS or DSCP for IPv4 and IPv6 resp. with the values configured for
56  * the tswtcl_data.
57  */
58 /* ARGSUSED */
59 int
tswtcl_process(mblk_t ** mpp,tswtcl_data_t * tswtcl_data,ipp_action_id_t * next_action)60 tswtcl_process(mblk_t **mpp, tswtcl_data_t *tswtcl_data,
61     ipp_action_id_t *next_action)
62 {
63 	ipha_t *ipha;
64 	hrtime_t now;
65 	ip6_t *ip6_hdr;
66 	uint32_t pkt_len;
67 	mblk_t *mp = *mpp;
68 	hrtime_t deltaT;
69 	uint64_t bitsinwin;
70 	uint32_t min = 0, additive, rnd;
71 	tswtcl_cfg_t *cfg_parms = tswtcl_data->cfg_parms;
72 
73 	if (mp == NULL) {
74 		tswtcl0dbg(("tswtcl_process: null mp!\n"));
75 		atomic_inc_64(&tswtcl_data->epackets);
76 		return (EINVAL);
77 	}
78 
79 	if (mp->b_datap->db_type != M_DATA) {
80 		if ((mp->b_cont != NULL) &&
81 		    (mp->b_cont->b_datap->db_type == M_DATA)) {
82 			mp = mp->b_cont;
83 		} else {
84 			tswtcl0dbg(("tswtcl_process: no data\n"));
85 			atomic_inc_64(&tswtcl_data->epackets);
86 			return (EINVAL);
87 		}
88 	}
89 
90 	/* Figure out the ToS/Traffic Class and length from the message */
91 	if ((mp->b_wptr - mp->b_rptr) < IP_SIMPLE_HDR_LENGTH) {
92 		if (!pullupmsg(mp, IP_SIMPLE_HDR_LENGTH)) {
93 			tswtcl0dbg(("tswtcl_process: pullup error\n"));
94 			atomic_inc_64(&tswtcl_data->epackets);
95 			return (EINVAL);
96 		}
97 	}
98 	ipha = (ipha_t *)mp->b_rptr;
99 	if (IPH_HDR_VERSION(ipha) == IPV4_VERSION) {
100 		pkt_len = ntohs(ipha->ipha_length);
101 	} else {
102 		ip6_hdr = (ip6_t *)mp->b_rptr;
103 		pkt_len = ntohs(ip6_hdr->ip6_plen) +
104 		    ip_hdr_length_v6(mp, ip6_hdr);
105 	}
106 
107 	/* Convert into bits */
108 	pkt_len <<= 3;
109 
110 	/* Get current time */
111 	now = gethrtime();
112 
113 	/* Update the avg_rate and win_front tswtcl_data */
114 	mutex_enter(&tswtcl_data->tswtcl_lock);
115 
116 	/* avg_rate = bits/sec and window in msec */
117 	bitsinwin = ((uint64_t)tswtcl_data->avg_rate * cfg_parms->window /
118 	    1000) + pkt_len;
119 
120 	deltaT = now - tswtcl_data->win_front + cfg_parms->nsecwindow;
121 
122 	tswtcl_data->avg_rate = (uint64_t)bitsinwin * METER_SEC_TO_NSEC /
123 	    deltaT;
124 	tswtcl_data->win_front = now;
125 
126 	if (tswtcl_data->avg_rate <= cfg_parms->committed_rate) {
127 		*next_action = cfg_parms->green_action;
128 	} else if (tswtcl_data->avg_rate <= cfg_parms->peak_rate) {
129 		/*
130 		 * Compute the probability:
131 		 *
132 		 * p0 = (avg_rate - committed_rate) / avg_rate
133 		 *
134 		 * Yellow with probability p0
135 		 * Green with probability (1 - p0)
136 		 *
137 		 */
138 		uint32_t aminusc;
139 
140 		/* Get a random no. betweeen 0 and avg_rate */
141 		(void) random_get_pseudo_bytes((uint8_t *)&additive,
142 		    sizeof (additive));
143 		rnd = min + (additive % (tswtcl_data->avg_rate - min + 1));
144 
145 		aminusc = tswtcl_data->avg_rate - cfg_parms->committed_rate;
146 		if (aminusc >= rnd) {
147 			*next_action = cfg_parms->yellow_action;
148 		} else {
149 			*next_action = cfg_parms->green_action;
150 		}
151 	} else {
152 		/*
153 		 * Compute the probability:
154 		 *
155 		 * p1 = (avg_rate - peak_rate) / avg_rate
156 		 * p2 = (peak_rate - committed_rate) / avg_rate
157 		 *
158 		 * Red with probability p1
159 		 * Yellow with probability p2
160 		 * Green with probability (1 - (p1 + p2))
161 		 *
162 		 */
163 		uint32_t  aminusp;
164 
165 		/* Get a random no. betweeen 0 and avg_rate */
166 		(void) random_get_pseudo_bytes((uint8_t *)&additive,
167 		    sizeof (additive));
168 		rnd = min + (additive % (tswtcl_data->avg_rate - min + 1));
169 
170 		aminusp = tswtcl_data->avg_rate - cfg_parms->peak_rate;
171 
172 		if (aminusp >= rnd) {
173 			*next_action = cfg_parms->red_action;
174 		} else if ((cfg_parms->pminusc + aminusp) >= rnd) {
175 			*next_action = cfg_parms->yellow_action;
176 		} else {
177 			*next_action = cfg_parms->green_action;
178 		}
179 
180 	}
181 	mutex_exit(&tswtcl_data->tswtcl_lock);
182 
183 	/* Update Stats */
184 	if (*next_action == cfg_parms->green_action) {
185 		atomic_inc_64(&tswtcl_data->green_packets);
186 		atomic_add_64(&tswtcl_data->green_bits, pkt_len);
187 	} else if (*next_action == cfg_parms->yellow_action) {
188 		atomic_inc_64(&tswtcl_data->yellow_packets);
189 		atomic_add_64(&tswtcl_data->yellow_bits, pkt_len);
190 	} else {
191 		ASSERT(*next_action == cfg_parms->red_action);
192 		atomic_inc_64(&tswtcl_data->red_packets);
193 		atomic_add_64(&tswtcl_data->red_bits, pkt_len);
194 	}
195 	return (0);
196 }
197