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 2004 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/bitmap.h> 30 #include <sys/stream.h> 31 #include <sys/strsubr.h> 32 #define _SUN_TPI_VERSION 2 33 #include <sys/tihdr.h> 34 #include <sys/suntpi.h> 35 36 /* 37 * Hash table parameters for tpi_provinfo_table. 38 */ 39 #define TPI_HASH_BITS 4 40 #define TPI_NHASH (1 << TPI_HASH_BITS) 41 42 /* 43 * Use the first element in the key for the hash. 44 */ 45 #define TPI_HASH(p) ((((uintptr_t *)p)[0] >> tpi_hashshift) % TPI_NHASH) 46 /* 47 * SAMESTR is a very confusing name. LAST_QUEUE is introduced for readability. 48 */ 49 #define LAST_QUEUE(q) (!SAMESTR(q)) 50 51 static tpi_provinfo_t *tpi_provinfo_table[TPI_NHASH]; 52 static kmutex_t tpi_provinfo_lock; 53 static int tpi_hashshift; 54 55 /* 56 * In most cases there is some transport provider (like tcp or udp) below 57 * transport user (like timod or sockets). However, it is possible to construct 58 * stream without transport provider (e.g. by pushing timod into FIFO). It is 59 * hardly of any use, but this condition was observed with sparcv9 abi tests. 60 * To count for such special case, a special tpi_nullprov static data is 61 * provided to cache information about such degenerated null-transport case. 62 */ 63 static tpi_provinfo_t tpi_nullprov; /* Placeholder for null transport */ 64 65 /* 66 * Initialise the TPI support routines. Called from strinit(). 67 */ 68 void 69 tpi_init() 70 { 71 mutex_init(&tpi_provinfo_lock, NULL, MUTEX_DEFAULT, NULL); 72 73 /* 74 * Calculate the right shift for hashing a tpi_provinfo_t. 75 */ 76 tpi_hashshift = highbit(sizeof (tpi_provinfo_t)); 77 } 78 79 /* 80 * Generate a downstream signature given the write-side queue. It 81 * passes back the size of the generated key in *keylenp. This routine 82 * cannot multithread as it returns a pointer to a static data item. 83 * 84 * There is no way (in the current module loading infrastructure) to 85 * _absolutely_ guarantee that the key below uniquely identifies an 86 * arrangement of modules and drivers. A module _might_ be unloaded and 87 * another module _might_ be loaded such that the qi_minfo is at _exactly_ 88 * same kernel address, and then it _might_ be placed in a transport 89 * provider stream in exactly the same configuration (modules above and 90 * below all identical) - but it would take quite a few coincidences 91 * and modules loading and unloading does not usually happen n times a 92 * second... 93 */ 94 static void * 95 tpi_makekey(queue_t *q, size_t *keylenp) 96 { 97 static uintptr_t *key = NULL; 98 int i; 99 100 ASSERT(q != NULL); 101 ASSERT(MUTEX_HELD(&tpi_provinfo_lock)); 102 103 /* assert this queue is write queue and qprocson() is called before */ 104 ASSERT((q->q_flag & QREADR) == 0); 105 ASSERT(q->q_next != NULL); 106 107 /* 108 * This can be global because tpi_makekey is called with 109 * tpi_provinfo_lock. 110 */ 111 if (key == NULL) 112 key = kmem_alloc((nstrpush + 1) * sizeof (uintptr_t), KM_SLEEP); 113 114 ASSERT(key != NULL); 115 116 /* 117 * Go down q_next to the driver, but no further. We use the qi_minfo 118 * because we can find in from the queue and it is a stable part of 119 * any driver/module infrastructure. 120 */ 121 for (i = 0; !LAST_QUEUE(q) && (q = q->q_next) != NULL; ++i) { 122 ASSERT(i < nstrpush + 1); 123 key[i] = (uintptr_t)q->q_qinfo->qi_minfo; 124 } 125 126 /* 127 * Allocate the actual key with the proper length, and pass it 128 * all back. 129 */ 130 *keylenp = i * sizeof (uintptr_t); 131 return ((void *)key); 132 } 133 134 /* 135 * Find an existing provider entry given a queue pointer, or allocate a 136 * new empty entry if not found. Because this routine calls kmem_alloc 137 * with KM_SLEEP, and because it traverses the q_next pointers of a stream 138 * it must be called with a proper user context and within a perimeter 139 * which protects the STREAM e.g. an open routine. This routine always 140 * returns a valid pointer. 141 */ 142 tpi_provinfo_t * 143 tpi_findprov(queue_t *q) 144 { 145 void *key; 146 size_t keylen; 147 tpi_provinfo_t **tpp; 148 149 mutex_enter(&tpi_provinfo_lock); 150 151 /* 152 * Must hold tpi_provinfo_lock since tpi_makekey() returns a pointer 153 * to static data. 154 */ 155 key = tpi_makekey(WR(q), &keylen); 156 157 if (keylen == 0) { 158 /* there is nothing below us, return special nullprov entry */ 159 mutex_exit(&tpi_provinfo_lock); 160 return (&tpi_nullprov); 161 } 162 163 /* 164 * Look for an existing entry, or the place to put a new one. 165 */ 166 for (tpp = &tpi_provinfo_table[TPI_HASH(key)]; *tpp != NULL; 167 tpp = &(*tpp)->tpi_next) { 168 if ((*tpp)->tpi_keylen == keylen && 169 bcmp((*tpp)->tpi_key, key, keylen) == 0) { 170 mutex_exit(&tpi_provinfo_lock); 171 return (*tpp); 172 } 173 } 174 175 /* 176 * Allocate and fill in the new tpi_provinfo_t. 177 */ 178 *tpp = kmem_zalloc(sizeof (tpi_provinfo_t), KM_SLEEP); 179 (*tpp)->tpi_key = kmem_alloc(keylen, KM_SLEEP); 180 bcopy(key, (*tpp)->tpi_key, keylen); 181 (*tpp)->tpi_keylen = keylen; 182 mutex_init(&(*tpp)->tpi_lock, NULL, MUTEX_DEFAULT, NULL); 183 184 mutex_exit(&tpi_provinfo_lock); 185 return (*tpp); 186 } 187 188 /* 189 * Allocate a TPI ACK reusing the old message if possible. 190 */ 191 mblk_t * 192 tpi_ack_alloc(mblk_t *mp, size_t size, uchar_t db_type, t_scalar_t prim) 193 { 194 mblk_t *omp = mp; 195 196 if ((mp = reallocb(mp, size, 0)) == NULL) { 197 freemsg(omp); 198 return (NULL); 199 } 200 if (mp->b_cont != NULL) { 201 freemsg(mp->b_cont); 202 mp->b_cont = NULL; 203 } 204 mp->b_datap->db_type = db_type; 205 mp->b_wptr = mp->b_rptr + size; 206 ((union T_primitives *)mp->b_rptr)->type = prim; 207 return (mp); 208 } 209