xref: /titanic_41/usr/src/uts/common/ipp/meters/tswtcl.c (revision 7c2fbfb345896881c631598ee3852ce9ce33fb07)
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 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <sys/kmem.h>
31 #include <sys/random.h>
32 #include <netinet/in.h>
33 #include <netinet/in_systm.h>
34 #include <netinet/ip6.h>
35 #include <inet/common.h>
36 #include <inet/ip.h>
37 #include <inet/ip6.h>
38 #include <ipp/meters/meter_impl.h>
39 
40 /*
41  * Module : Time Sliding Window meter - tswtclmtr
42  * Description
43  * This module implements the metering part of RFC 2859. It accepts the
44  * committed rate, peak rate and the window for a flow and determines
45  * if the flow is within the committed/peak rate and assigns the appropriate
46  * next action.
47  * The meter provides an estimate of the running average bandwidth for the
48  * flow over the specified window. It uses probability to benefit TCP flows
49  * as it reduces the likelihood of dropping multiple packets within a TCP
50  * window without adversely effecting UDP flows.
51  */
52 
53 int tswtcl_debug = 0;
54 
55 /*
56  * Given a packet and the tswtcl_data it belongs to, this routine meters the
57  * ToS or DSCP for IPv4 and IPv6 resp. with the values configured for
58  * the tswtcl_data.
59  */
60 /* ARGSUSED */
61 int
62 tswtcl_process(mblk_t **mpp, tswtcl_data_t *tswtcl_data,
63     ipp_action_id_t *next_action)
64 {
65 	ipha_t *ipha;
66 	hrtime_t now;
67 	ip6_t *ip6_hdr;
68 	uint32_t pkt_len;
69 	mblk_t *mp = *mpp;
70 	hrtime_t deltaT;
71 	uint64_t bitsinwin;
72 	uint32_t min = 0, additive, rnd;
73 	tswtcl_cfg_t *cfg_parms = tswtcl_data->cfg_parms;
74 
75 	if (mp == NULL) {
76 		tswtcl0dbg(("tswtcl_process: null mp!\n"));
77 		atomic_add_64(&tswtcl_data->epackets, 1);
78 		return (EINVAL);
79 	}
80 
81 	if (mp->b_datap->db_type != M_DATA) {
82 		if ((mp->b_cont != NULL) &&
83 		    (mp->b_cont->b_datap->db_type == M_DATA)) {
84 			mp = mp->b_cont;
85 		} else {
86 			tswtcl0dbg(("tswtcl_process: no data\n"));
87 			atomic_add_64(&tswtcl_data->epackets, 1);
88 			return (EINVAL);
89 		}
90 	}
91 
92 	/* Figure out the ToS/Traffic Class and length from the message */
93 	if ((mp->b_wptr - mp->b_rptr) < IP_SIMPLE_HDR_LENGTH) {
94 		if (!pullupmsg(mp, IP_SIMPLE_HDR_LENGTH)) {
95 			tswtcl0dbg(("tswtcl_process: pullup error\n"));
96 			atomic_add_64(&tswtcl_data->epackets, 1);
97 			return (EINVAL);
98 		}
99 	}
100 	ipha = (ipha_t *)mp->b_rptr;
101 	if (IPH_HDR_VERSION(ipha) == IPV4_VERSION) {
102 		pkt_len = ntohs(ipha->ipha_length);
103 	} else {
104 		ip6_hdr = (ip6_t *)mp->b_rptr;
105 		pkt_len = ntohs(ip6_hdr->ip6_plen) +
106 		    ip_hdr_length_v6(mp, ip6_hdr);
107 	}
108 
109 	/* Convert into bits */
110 	pkt_len <<= 3;
111 
112 	/* Get current time */
113 	now = gethrtime();
114 
115 	/* Update the avg_rate and win_front tswtcl_data */
116 	mutex_enter(&tswtcl_data->tswtcl_lock);
117 
118 	/* avg_rate = bits/sec and window in msec */
119 	bitsinwin = ((uint64_t)tswtcl_data->avg_rate * cfg_parms->window /
120 	    1000) + pkt_len;
121 
122 	deltaT = now - tswtcl_data->win_front + cfg_parms->nsecwindow;
123 
124 	tswtcl_data->avg_rate = (uint64_t)bitsinwin * METER_SEC_TO_NSEC /
125 	    deltaT;
126 	tswtcl_data->win_front = now;
127 
128 	if (tswtcl_data->avg_rate <= cfg_parms->committed_rate) {
129 		*next_action = cfg_parms->green_action;
130 	} else if (tswtcl_data->avg_rate <= cfg_parms->peak_rate) {
131 		/*
132 		 * Compute the probability:
133 		 *
134 		 * p0 = (avg_rate - committed_rate) / avg_rate
135 		 *
136 		 * Yellow with probability p0
137 		 * Green with probability (1 - p0)
138 		 *
139 		 */
140 		uint32_t aminusc;
141 
142 		/* Get a random no. betweeen 0 and avg_rate */
143 		(void) random_get_pseudo_bytes((uint8_t *)&additive,
144 		    sizeof (additive));
145 		rnd = min + (additive % (tswtcl_data->avg_rate - min + 1));
146 
147 		aminusc = tswtcl_data->avg_rate - cfg_parms->committed_rate;
148 		if (aminusc >= rnd) {
149 			*next_action = cfg_parms->yellow_action;
150 		} else {
151 			*next_action = cfg_parms->green_action;
152 		}
153 	} else {
154 		/*
155 		 * Compute the probability:
156 		 *
157 		 * p1 = (avg_rate - peak_rate) / avg_rate
158 		 * p2 = (peak_rate - committed_rate) / avg_rate
159 		 *
160 		 * Red with probability p1
161 		 * Yellow with probability p2
162 		 * Green with probability (1 - (p1 + p2))
163 		 *
164 		 */
165 		uint32_t  aminusp;
166 
167 		/* Get a random no. betweeen 0 and avg_rate */
168 		(void) random_get_pseudo_bytes((uint8_t *)&additive,
169 		    sizeof (additive));
170 		rnd = min + (additive % (tswtcl_data->avg_rate - min + 1));
171 
172 		aminusp = tswtcl_data->avg_rate - cfg_parms->peak_rate;
173 
174 		if (aminusp >= rnd) {
175 			*next_action = cfg_parms->red_action;
176 		} else if ((cfg_parms->pminusc + aminusp) >= rnd) {
177 			*next_action = cfg_parms->yellow_action;
178 		} else {
179 			*next_action = cfg_parms->green_action;
180 		}
181 
182 	}
183 	mutex_exit(&tswtcl_data->tswtcl_lock);
184 
185 	/* Update Stats */
186 	if (*next_action == cfg_parms->green_action) {
187 		atomic_add_64(&tswtcl_data->green_packets, 1);
188 		atomic_add_64(&tswtcl_data->green_bits, pkt_len);
189 	} else if (*next_action == cfg_parms->yellow_action) {
190 		atomic_add_64(&tswtcl_data->yellow_packets, 1);
191 		atomic_add_64(&tswtcl_data->yellow_bits, pkt_len);
192 	} else {
193 		ASSERT(*next_action == cfg_parms->red_action);
194 		atomic_add_64(&tswtcl_data->red_packets, 1);
195 		atomic_add_64(&tswtcl_data->red_bits, pkt_len);
196 	}
197 	return (0);
198 }
199