xref: /illumos-gate/usr/src/uts/common/ipp/dscpmk/dscpmk.c (revision 3ba944265c4ae1fcf23ef758537c2e4f4feec16e)
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/atomic.h>
29 #include <sys/pattr.h>
30 #include <netinet/in.h>
31 #include <netinet/ip6.h>
32 #include <inet/common.h>
33 #include <inet/ip.h>
34 #include <inet/ip6.h>
35 #include <ipp/dscpmk/dscpmk_impl.h>
36 
37 /* Module to mark the ToS/DS field for a given packet */
38 
39 /* Debug level */
40 int dscpmk_debug = 0;
41 
42 /*
43  * Given a packet, this routine marks the ToS or DSCP for IPv4 and IPv6 resp.
44  * using the configured dscp_map.
45  * Note that this module does not change the ECN bits.
46  */
47 int
48 dscpmk_process(mblk_t **mpp, dscpmk_data_t *dscpmk_data, ip_proc_t proc)
49 {
50 	ipha_t *ipha;
51 	ip6_t *ip6_hdr;
52 	boolean_t is_v4;
53 	uint8_t dscp, new_dscp;
54 	mblk_t *mp;
55 
56 	ASSERT((mpp != NULL) && (*mpp != NULL));
57 	mp = *mpp;
58 
59 	/*
60 	 * The action module will receive an M_DATA or an M_CTL followed
61 	 * by an M_DATA. In the latter case skip the M_CTL.
62 	 */
63 	if (mp->b_datap->db_type != M_DATA) {
64 		if ((mp->b_cont != NULL) &&
65 		    (mp->b_cont->b_datap->db_type == M_DATA)) {
66 			mp = mp->b_cont;
67 		} else {
68 			dscpmk0dbg(("dscpmk_process: no data\n"));
69 			atomic_inc_64(&dscpmk_data->epackets);
70 			return (EINVAL);
71 		}
72 	}
73 
74 	/* Pull-up needed? */
75 	if ((mp->b_wptr - mp->b_rptr) < IP_SIMPLE_HDR_LENGTH) {
76 		if (!pullupmsg(mp, IP_SIMPLE_HDR_LENGTH)) {
77 			dscpmk0dbg(("dscpmk_process: pullup failed\n"));
78 			atomic_inc_64(&dscpmk_data->epackets);
79 			return (EINVAL);
80 		}
81 	}
82 	ipha = (ipha_t *)mp->b_rptr;
83 
84 	/* Update global stats */
85 	atomic_inc_64(&dscpmk_data->npackets);
86 
87 	/*
88 	 * This should only be called for outgoing packets. For inbound packets
89 	 * proceed with the next action.
90 	 */
91 	if ((proc == IPP_LOCAL_IN) || (proc == IPP_FWD_IN)) {
92 		dscpmk2dbg(("dscpmk_process: cannot mark incoming packets\n"));
93 		atomic_inc_64(&dscpmk_data->ipackets);
94 		return (0);
95 	}
96 
97 	/* Figure out the ToS or the Traffic Class from the message */
98 	if (IPH_HDR_VERSION(ipha) == IPV4_VERSION) {
99 		dscp = ipha->ipha_type_of_service;
100 		is_v4 = B_TRUE;
101 	} else {
102 		ip6_hdr = (ip6_t *)mp->b_rptr;
103 		dscp = __IPV6_TCLASS_FROM_FLOW(ip6_hdr->ip6_vcf);
104 		is_v4 = B_FALSE;
105 	}
106 
107 	/*
108 	 * Select the new dscp from the dscp_map after ignoring the
109 	 * ECN/CU from dscp (hence dscp >> 2). new_dscp will be the
110 	 * 6-bit DSCP value.
111 	 */
112 	new_dscp = dscpmk_data->dscp_map[dscp >> 2];
113 
114 	/* Update stats for this new_dscp */
115 	atomic_inc_64(&dscpmk_data->dscp_stats[new_dscp].npackets);
116 
117 	/*
118 	 * if new_dscp is same as the original, update stats and
119 	 * return.
120 	 */
121 	if (new_dscp == (dscp >> 2)) {
122 		atomic_inc_64(&dscpmk_data->unchanged);
123 		return (0);
124 	}
125 
126 	/* Get back the ECN/CU value from the original dscp */
127 	new_dscp = (new_dscp << 2) | (dscp & 0x3);
128 
129 	atomic_inc_64(&dscpmk_data->changed);
130 	/*
131 	 * IPv4 : ToS structure -- RFC 791
132 	 *
133 	 *	  0   1   2   3   4   5   6   7
134 	 *	+---+---+---+---+---+---+---+---+
135 	 *	| IP Precd  | D	| T | R	| 0 | 0	|
136 	 *	|	    |	|   |	|   |	|
137 	 *	+---+---+---+---+---+---+---+---+
138 	 *
139 	 * For Backward Compatability the diff serv DSCP will be mapped
140 	 * to the 3-bits Precedence field. DTR is not supported. Thus,
141 	 * the following Class Seletor CodePoints are reserved from this
142 	 * purpose : xxx000; where x is 0 or 1 (note the last 2 bits are
143 	 * 00) -- see RFC 2474.
144 	 */
145 
146 	if (is_v4) {
147 		ipha->ipha_type_of_service = new_dscp;
148 		/*
149 		 * If the hardware supports checksumming, we don't need
150 		 * to do anything.
151 		 */
152 		if (!(mp->b_datap->db_struioun.cksum.flags &
153 		    HCK_IPV4_HDRCKSUM)) {
154 			ipha->ipha_hdr_checksum = 0;
155 			ipha->ipha_hdr_checksum = ip_csum_hdr(ipha);
156 		}
157 	} else {
158 
159 	/*
160 	 * IPv6 : DSCP field structure is as given -- RFC 2474
161 	 *
162 	 *	  0   1   2   3   4   5   6   7
163 	 *	+---+---+---+---+---+---+---+---+
164 	 *	|	DSCP		| CU	|
165 	 *	|			|	|
166 	 *	+---+---+---+---+---+---+---+---+
167 	 *
168 	 * CU -- Currently Unused
169 	 *
170 	 * the 32 bit vcf consists of version (4 bits), Traffic class (8 bits)
171 	 * and flow id (20 bits). Need to take care of Big/Little-Endianess.
172 	 */
173 #ifdef _BIG_ENDIAN
174 		ip6_hdr->ip6_vcf = (ip6_hdr->ip6_vcf & TCLASS_MASK) |
175 		    (new_dscp << 20);
176 #else
177 		ip6_hdr->ip6_vcf = (ip6_hdr->ip6_vcf & TCLASS_MASK) |
178 		    ((new_dscp >> 4) | ((new_dscp << 12) & 0xF000));
179 #endif
180 	}
181 
182 	return (0);
183 }
184