xref: /titanic_41/usr/src/uts/common/ipp/dscpmk/dscpmk.c (revision ea394cb00fd96864e34d2841b4a22357b621c78f)
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/atomic.h>
31 #include <sys/pattr.h>
32 #include <netinet/in.h>
33 #include <netinet/ip6.h>
34 #include <inet/common.h>
35 #include <inet/ip.h>
36 #include <inet/ip6.h>
37 #include <ipp/dscpmk/dscpmk_impl.h>
38 
39 /* Module to mark the ToS/DS field for a given packet */
40 
41 /* Debug level */
42 int dscpmk_debug = 0;
43 
44 /*
45  * Given a packet, this routine marks the ToS or DSCP for IPv4 and IPv6 resp.
46  * using the configured dscp_map.
47  * Note that this module does not change the ECN bits.
48  */
49 int
50 dscpmk_process(mblk_t **mpp, dscpmk_data_t *dscpmk_data, ip_proc_t proc)
51 {
52 	ipha_t *ipha;
53 	ip6_t *ip6_hdr;
54 	boolean_t is_v4;
55 	uint8_t dscp, new_dscp;
56 	mblk_t *mp;
57 
58 	ASSERT((mpp != NULL) && (*mpp != NULL));
59 	mp = *mpp;
60 
61 	/*
62 	 * The action module will receive an M_DATA or an M_CTL followed
63 	 * by an M_DATA. In the latter case skip the M_CTL.
64 	 */
65 	if (mp->b_datap->db_type != M_DATA) {
66 		if ((mp->b_cont != NULL) &&
67 		    (mp->b_cont->b_datap->db_type == M_DATA)) {
68 			mp = mp->b_cont;
69 		} else {
70 			dscpmk0dbg(("dscpmk_process: no data\n"));
71 			atomic_add_64(&dscpmk_data->epackets, 1);
72 			return (EINVAL);
73 		}
74 	}
75 
76 	/* Pull-up needed? */
77 	if ((mp->b_wptr - mp->b_rptr) < IP_SIMPLE_HDR_LENGTH) {
78 		if (!pullupmsg(mp, IP_SIMPLE_HDR_LENGTH)) {
79 			dscpmk0dbg(("dscpmk_process: pullup failed\n"));
80 			atomic_add_64(&dscpmk_data->epackets, 1);
81 			return (EINVAL);
82 		}
83 	}
84 	ipha = (ipha_t *)mp->b_rptr;
85 
86 	/* Update global stats */
87 	atomic_add_64(&dscpmk_data->npackets, 1);
88 
89 	/*
90 	 * This should only be called for outgoing packets. For inbound packets
91 	 * proceed with the next action.
92 	 */
93 	if ((proc == IPP_LOCAL_IN) || (proc == IPP_FWD_IN)) {
94 		dscpmk2dbg(("dscpmk_process: cannot mark incoming packets\n"));
95 		atomic_add_64(&dscpmk_data->ipackets, 1);
96 		return (0);
97 	}
98 
99 	/* Figure out the ToS or the Traffic Class from the message */
100 	if (IPH_HDR_VERSION(ipha) == IPV4_VERSION) {
101 		dscp = ipha->ipha_type_of_service;
102 		is_v4 = B_TRUE;
103 	} else {
104 		ip6_hdr = (ip6_t *)mp->b_rptr;
105 		dscp = __IPV6_TCLASS_FROM_FLOW(ip6_hdr->ip6_vcf);
106 		is_v4 = B_FALSE;
107 	}
108 
109 	/*
110 	 * Select the new dscp from the dscp_map after ignoring the
111 	 * ECN/CU from dscp (hence dscp >> 2). new_dscp will be the
112 	 * 6-bit DSCP value.
113 	 */
114 	new_dscp = dscpmk_data->dscp_map[dscp >> 2];
115 
116 	/* Update stats for this new_dscp */
117 	atomic_add_64(&dscpmk_data->dscp_stats[new_dscp].npackets, 1);
118 
119 	/*
120 	 * if new_dscp is same as the original, update stats and
121 	 * return.
122 	 */
123 	if (new_dscp == (dscp >> 2)) {
124 		atomic_add_64(&dscpmk_data->unchanged, 1);
125 		return (0);
126 	}
127 
128 	/* Get back the ECN/CU value from the original dscp */
129 	new_dscp = (new_dscp << 2) | (dscp & 0x3);
130 
131 	atomic_add_64(&dscpmk_data->changed, 1);
132 	/*
133 	 * IPv4 : ToS structure -- RFC 791
134 	 *
135 	 *	  0   1   2   3   4   5   6   7
136 	 *	+---+---+---+---+---+---+---+---+
137 	 *	| IP Precd  | D	| T | R	| 0 | 0	|
138 	 *	|	    |	|   |	|   |	|
139 	 *	+---+---+---+---+---+---+---+---+
140 	 *
141 	 * For Backward Compatability the diff serv DSCP will be mapped
142 	 * to the 3-bits Precedence field. DTR is not supported. Thus,
143 	 * the following Class Seletor CodePoints are reserved from this
144 	 * purpose : xxx000; where x is 0 or 1 (note the last 2 bits are
145 	 * 00) -- see RFC 2474.
146 	 */
147 
148 	if (is_v4) {
149 		ipha->ipha_type_of_service = new_dscp;
150 		/*
151 		 * If the hardware supports checksumming, we don't need
152 		 * to do anything.
153 		 */
154 		if (!(mp->b_datap->db_struioun.cksum.flags &
155 		    HCK_IPV4_HDRCKSUM)) {
156 			ipha->ipha_hdr_checksum = 0;
157 			ipha->ipha_hdr_checksum = ip_csum_hdr(ipha);
158 		}
159 	} else {
160 
161 	/*
162 	 * IPv6 : DSCP field structure is as given -- RFC 2474
163 	 *
164 	 *	  0   1   2   3   4   5   6   7
165 	 *	+---+---+---+---+---+---+---+---+
166 	 *	|	DSCP		| CU	|
167 	 *	|			|	|
168 	 *	+---+---+---+---+---+---+---+---+
169 	 *
170 	 * CU -- Currently Unused
171 	 *
172 	 * the 32 bit vcf consists of version (4 bits), Traffic class (8 bits)
173 	 * and flow id (20 bits). Need to take care of Big/Little-Endianess.
174 	 */
175 #ifdef _BIG_ENDIAN
176 		ip6_hdr->ip6_vcf = (ip6_hdr->ip6_vcf & TCLASS_MASK) |
177 		    (new_dscp << 20);
178 #else
179 		ip6_hdr->ip6_vcf = (ip6_hdr->ip6_vcf & TCLASS_MASK) |
180 		    ((new_dscp >> 4) | ((new_dscp << 12) & 0xF000));
181 #endif
182 	}
183 
184 	return (0);
185 }
186