/* $NetBSD: iscsi_utils.c,v 1.29 2023/11/25 10:08:27 mlelstv Exp $ */
/*-
* Copyright (c) 2004,2005,2006,2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Wasabi Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "iscsi_globals.h"
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/socketvar.h>
#include <sys/bswap.h>
#include <sys/atomic.h>
/*****************************************************************************
* Digest functions
*****************************************************************************/
/*****************************************************************
*
* CRC LOOKUP TABLE
* ================
* The following CRC lookup table was generated automagically
* by the Rocksoft^tm Model CRC Algorithm Table Generation
* Program V1.0 using the following model parameters:
*
* Width : 4 bytes.
* Poly : 0x1EDC6F41L
* Reverse : TRUE.
*
* For more information on the Rocksoft^tm Model CRC Algorithm,
* see the document titled "A Painless Guide to CRC Error
* Detection Algorithms" by Ross Williams
* (ross@guest.adelaide.edu.au.). This document is likely to be
* in the FTP archive "ftp.adelaide.edu.au/pub/rocksoft".
*
*****************************************************************/
STATIC uint32_t crc_table[256] = {
0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
};
/*
* gen_digest:
* Generate an iSCSI CRC32C digest over the given data.
*
* Parameters:
* buff The data
* len The length of the data in bytes
*
* Returns: The digest in network byte order
*/
uint32_t
gen_digest(const void *buff, size_t len)
{
const uint8_t *bp = (const uint8_t *) buff;
uint32_t crc = 0xffffffff;
while (len--) {
crc = ((crc >> 8) & 0x00ffffff) ^ crc_table[(crc ^ *bp++) & 0xff];
}
return htonl(bswap32(crc ^ 0xffffffff));
}
/*
* gen_digest_2:
* Generate an iSCSI CRC32C digest over the given data, which is split over
* two buffers.
*
* Parameters:
* buf1, buf2 The data
* len1, len2 The length of the data in bytes
*
* Returns: The digest in network byte order
*/
uint32_t
gen_digest_2(const void *buf1, size_t len1, const void *buf2, size_t len2)
{
const uint8_t *bp = (const uint8_t *) buf1;
uint32_t crc = 0xffffffff;
while (len1--) {
crc = ((crc >> 8) & 0x00ffffff) ^ crc_table[(crc ^ *bp++) & 0xff];
}
bp = (const uint8_t *) buf2;
while (len2--) {
crc = ((crc >> 8) & 0x00ffffff) ^ crc_table[(crc ^ *bp++) & 0xff];
}
return htonl(bswap32(crc ^ 0xffffffff));
}
/*****************************************************************************
* CCB management functions
*****************************************************************************/
/*
* get_ccb:
* Get a CCB for the SCSI operation, waiting if none is available.
*
* Parameter:
* sess The session containing this CCB
* waitok Whether waiting for a CCB is OK
*
* Returns: The CCB.
*/
ccb_t *
get_ccb(connection_t *conn, bool waitok)
{
ccb_t *ccb;
session_t *sess = conn->c_session;
mutex_enter(&sess->s_lock);
for (;;) {
ccb = TAILQ_FIRST(&sess->s_ccb_pool);
DEB(100, ("get_ccb: ccb = %p, waitok = %d\n", ccb, waitok));
if (ccb != NULL) {
TAILQ_REMOVE(&sess->s_ccb_pool, ccb, ccb_chain);
break;
}
if (!waitok)
break;
cv_wait(&sess->s_ccb_cv, &sess->s_lock);
}
mutex_exit(&sess->s_lock);
if (ccb == NULL) {
DEB(15, ("get_ccb: failed"));
return NULL;
}
ccb->ccb_flags = 0;
ccb->ccb_timedout = TOUT_NONE;
ccb->ccb_xs = NULL;
ccb->ccb_temp_data = NULL;
ccb->ccb_text_data = NULL;
ccb->ccb_status = ISCSI_STATUS_SUCCESS;
ccb->ccb_ITT = (ccb->ccb_ITT & 0xffffff);
ccb->ccb_disp = CCBDISP_NOWAIT;
ccb->ccb_connection = conn;
ccb->ccb_num_timeouts = 0;
mutex_enter(&conn->c_lock);
conn->c_usecount++;
mutex_exit(&conn->c_lock);
DEBC(conn, 15, (
"get_ccb: ccb = %p, usecount = %d\n",
ccb, conn->c_usecount));
return ccb;
}
/*
* free_ccb:
* Put a CCB back onto the free list.
*
* Parameter: The CCB.
*/
void
free_ccb(ccb_t *ccb)
{
session_t *sess = ccb->ccb_session;
connection_t *conn = ccb->ccb_connection;
pdu_t *pdu;
DEBC(conn, 15, (
"free_ccb: ccb = %p, usecount = %d\n",
ccb, conn->c_usecount-1));
KASSERT((ccb->ccb_flags & CCBF_WAITQUEUE) == 0);
ccb->ccb_connection = NULL;
mutex_enter(&conn->c_lock);
conn->c_usecount--;
mutex_exit(&conn->c_lock);
if (ccb->ccb_disp > CCBDISP_NOWAIT) {
DEBOUT(("Freeing CCB with disp %d\n",ccb->ccb_disp));
}
ccb->ccb_disp = CCBDISP_UNUSED;
/* free temporary data */
if (ccb->ccb_temp_data != NULL) {
free(ccb->ccb_temp_data, M_TEMP);
}
if (ccb->ccb_text_data != NULL) {
free(ccb->ccb_text_data, M_TEMP);
}
/* free PDU waiting for ACK */
if ((pdu = ccb->ccb_pdu_waiting) != NULL) {
ccb->ccb_pdu_waiting = NULL;
mutex_enter(&conn->c_lock);
if ((pdu->pdu_flags & PDUF_INQUEUE) != 0) {
TAILQ_REMOVE(&conn->c_pdus_to_send, pdu, pdu_send_chain);
pdu->pdu_flags &= ~PDUF_INQUEUE;
}
mutex_exit(&conn->c_lock);
free_pdu(pdu);
}
mutex_enter(&sess->s_lock);
TAILQ_INSERT_TAIL(&sess->s_ccb_pool, ccb, ccb_chain);
cv_broadcast(&sess->s_ccb_cv);
mutex_exit(&sess->s_lock);
}
/*
* create_ccbs
* "Create" the pool of CCBs. This doesn't actually create the CCBs
* (they are allocated with the session structure), but it links them
* into the free-list.
*
* Parameter: The session owning the CCBs.
*/
void
create_ccbs(session_t *sess)
{
int i;
ccb_t *ccb;
int sid = sess->s_id << 8;
/* Note: CCBs are initialized to 0 with connection structure */
for (i = 0, ccb = sess->s_ccb; i < CCBS_PER_SESSION; i++, ccb++) {
ccb->ccb_ITT = i | sid;
ccb->ccb_session = sess;
callout_init(&ccb->ccb_timeout, CALLOUT_MPSAFE);
callout_setfunc(&ccb->ccb_timeout, ccb_timeout_co, ccb);
DEB(9, ("Create_ccbs: ccb %p itt %x\n", ccb, ccb->ccb_ITT));
TAILQ_INSERT_HEAD(&sess->s_ccb_pool, ccb, ccb_chain);
}
}
/*
* destroy_ccbs
* Kill the callouts
*
* Parameter: The session owning the CCBs.
*/
void
destroy_ccbs(session_t *sess)
{
int i;
ccb_t *ccb;
/* Note: CCBs are initialized to 0 with connection structure */
for (i = 0, ccb = sess->s_ccb; i < CCBS_PER_SESSION; i++, ccb++) {
callout_halt(&ccb->ccb_timeout, NULL);
callout_destroy(&ccb->ccb_timeout);
DEB(9, ("destroy_ccbs: ccb %p itt %x\n", ccb, ccb->ccb_ITT));
KASSERT((ccb->ccb_flags & CCBF_WAITQUEUE) == 0);
KASSERT(ccb->ccb_disp == CCBDISP_UNUSED);
KASSERT(ccb->ccb_connection == NULL);
TAILQ_REMOVE(&sess->s_ccb_pool, ccb, ccb_chain);
}
}
/*
* suspend_ccb:
* Put CCB on wait queue
*/
void
suspend_ccb(ccb_t *ccb, bool yes)
{
connection_t *conn;
conn = ccb->ccb_connection;
KASSERT(conn != NULL);
KASSERT(mutex_owned(&conn->c_lock));
if (yes) {
KASSERT((ccb->ccb_flags & CCBF_WAITQUEUE) == 0);
TAILQ_INSERT_TAIL(&conn->c_ccbs_waiting, ccb, ccb_chain);
ccb->ccb_flags |= CCBF_WAITQUEUE;
} else if (ccb->ccb_flags & CCBF_WAITQUEUE) {
TAILQ_REMOVE(&conn->c_ccbs_waiting, ccb, ccb_chain);
ccb->ccb_flags &= ~CCBF_WAITQUEUE;
}
}
/*
* wake_ccb:
* Wake up (or dispose of) a CCB. Depending on the CCB's disposition,
* either wake up the requesting thread, signal SCSIPI that we're done,
* or just free the CCB for CCBDISP_FREE.
*
* Parameter: The CCB to handle and the new status of the CCB
*/
void
wake_ccb(ccb_t *ccb, uint32_t status)
{
ccb_disp_t disp;
connection_t *conn;
conn = ccb->ccb_connection;
KASSERT(conn != NULL);
DEBC(conn, 9, ("CCB %d done, ccb = %p, disp = %d\n",
ccb->ccb_CmdSN, ccb, ccb->ccb_disp));
ccb_timeout_stop(ccb);
mutex_enter(&conn->c_lock);
disp = ccb->ccb_disp;
if (disp <= CCBDISP_NOWAIT ||
(disp == CCBDISP_DEFER && conn->c_state <= ST_WINDING_DOWN)) {
mutex_exit(&conn->c_lock);
return;
}
suspend_ccb(ccb, FALSE);
/* change the disposition so nobody tries this again */
ccb->ccb_disp = CCBDISP_BUSY;
ccb->ccb_status = status;
if (disp == CCBDISP_WAIT)
cv_broadcast(&conn->c_ccb_cv);
mutex_exit(&conn->c_lock);
switch(disp) {
case CCBDISP_WAIT:
case CCBDISP_DEFER:
break;
case CCBDISP_SCSIPI:
iscsi_done(ccb);
/* FALLTHROUGH */
case CCBDISP_FREE:
free_ccb(ccb);
break;
default:
DEBC(conn, 1, ("CCB done, ccb = %p, invalid disposition %d", ccb, disp));
free_ccb(ccb);
break;
}
}
/*****************************************************************************
* PDU management functions
*****************************************************************************/
/*
* get_pdu:
* Get a PDU for the SCSI operation.
*
* Parameter:
* conn The connection this PDU should be associated with
* waitok OK to wait for PDU if TRUE
*
* Returns: The PDU or NULL if none is available and waitok is FALSE.
*/
pdu_t *
get_pdu(connection_t *conn, bool waitok)
{
pdu_t *pdu;
mutex_enter(&conn->c_lock);
for (;;) {
pdu = TAILQ_FIRST(&conn->c_pdu_pool);
if (pdu != NULL) {
TAILQ_REMOVE(&conn->c_pdu_pool, pdu, pdu_chain);
conn->c_pducount++;
break;
}
if (!waitok)
break;
cv_wait(&conn->c_pdu_cv, &conn->c_lock);
}
mutex_exit(&conn->c_lock);
if (pdu == NULL) {
DEB(15, ("get_pdu: failed"));
return NULL;
}
memset(pdu, 0, sizeof(pdu_t));
pdu->pdu_connection = conn;
pdu->pdu_disp = PDUDISP_FREE;
DEBC(conn, 15, ("get_pdu: pdu = %p, usecount = %d\n", pdu, conn->c_pducount));
return pdu;
}
/*
* free_pdu:
* Put a PDU back onto the free list.
*
* Parameter: The PDU.
*/
void
free_pdu(pdu_t *pdu)
{
connection_t *conn = pdu->pdu_connection;
pdu_disp_t pdisp;
DEBC(conn, 15, ("free_pdu: pdu = %p, usecount = %d\n", pdu, conn->c_pducount-1));
KASSERT((pdu->pdu_flags & PDUF_INQUEUE) == 0);
if (PDUDISP_UNUSED == (pdisp = pdu->pdu_disp)) {
DEBC(conn, 0, ("freeing UNUSED pdu\n"));
return;
}
pdu->pdu_disp = PDUDISP_UNUSED;
/* free temporary data in this PDU */
if (pdu->pdu_temp_data)
free(pdu->pdu_temp_data, M_TEMP);
mutex_enter(&conn->c_lock);
conn->c_pducount--;
TAILQ_INSERT_TAIL(&conn->c_pdu_pool, pdu, pdu_chain);
cv_broadcast(&conn->c_pdu_cv);
mutex_exit(&conn->c_lock);
}
/*
* create_pdus
* "Create" the pool of PDUs. This doesn't actually create the PDUs
* (they are allocated with the connection structure), but it links them
* into the free-list.
*
* Parameter: The connection owning the PDUs.
*/
void
create_pdus(connection_t *conn)
{
int i;
pdu_t *pdu;
/* Note: PDUs are initialized to 0 with connection structure */
for (i = 0, pdu = conn->c_pdu; i < PDUS_PER_CONNECTION; i++, pdu++) {
TAILQ_INSERT_HEAD(&conn->c_pdu_pool, pdu, pdu_chain);
}
}
/*****************************************************************************
* Serial Number management functions
*****************************************************************************/
/*
* init_sernum:
* Initialize serial number buffer variables.
*
* Parameter:
* buff The serial number buffer.
*/
void
init_sernum(sernum_buffer_t *buff)
{
buff->bottom = 0;
buff->top = 0;
buff->next_sn = 0;
buff->ExpSN = 0;
}
/*
* add_sernum:
* Add a received serial number to the buffer.
* If the serial number is smaller than the expected one, it is ignored.
* If it is larger, all missing serial numbers are added as well.
*
* Parameter:
* buff The serial number buffer.
* num The received serial number
*
* Returns:
* 0 if the received block is a duplicate
* 1 if the number is the expected one
* >1 if the number is > the expected value, in this case the
* return value is the number of unacknowledged blocks
* <0 if the buffer is full (i.e. an excessive number of blocks
* is unacknowledged)
*/
int
add_sernum(sernum_buffer_t *buff, uint32_t num)
{
int i, t, b;
uint32_t n;
int32_t diff;
/*
* next_sn is the next expected SN, so normally diff should be 1.
*/
n = buff->next_sn;
diff = (num - n) + 1;
if (diff <= 0) {
return 0; /* ignore if SN is smaller than expected (dup or retransmit) */
}
buff->next_sn = num + 1;
t = buff->top;
b = buff->bottom;
for (i = 0; i < diff; i++) {
buff->sernum[t] = n++;
buff->ack[t] = false;
t = (t + 1) % SERNUM_BUFFER_LENGTH;
if (t == b) {
DEB(1, ("AddSernum: Buffer Full! num %d, diff %d\n", num, diff));
return -1;
}
}
buff->top = t;
DEB(11, ("AddSernum bottom %d [%d], top %d, num %u, diff %d\n",
b, buff->sernum[b], buff->top, num, diff));
return diff;
}
/*
* ack_sernum:
* Mark a received serial number as acknowledged. This does not necessarily
* change the associated ExpSN if there are lower serial numbers in the
* buffer.
*
* Parameter:
* buff The serial number buffer.
* num The serial number to acknowledge.
*
* Returns: The value of ExpSN.
*/
uint32_t
ack_sernum(sernum_buffer_t *buff, uint32_t num)
{
int b = buff->bottom;
int t = buff->top;
/* shortcut for most likely case */
if (t == (b + 1) && num == buff->sernum[b]) {
/* buffer is now empty, reset top */
buff->top = b;
} else if (b != t) {
for (; b != t; b = (b + 1) % SERNUM_BUFFER_LENGTH) {
if (!sn_a_lt_b(buff->sernum[b], num))
break;
}
if (num == buff->sernum[b]) {
if (b == buff->bottom)
buff->bottom = (b + 1) % SERNUM_BUFFER_LENGTH;
else
buff->ack[b] = true;
}
for (b = buff->bottom, num = buff->sernum[b] - 1;
b != t && buff->ack[b]; b = (b + 1) % SERNUM_BUFFER_LENGTH) {
num = buff->sernum[b];
}
}
if (!sn_a_lt_b(num, buff->ExpSN))
buff->ExpSN = num + 1;
DEB(11, ("AckSernum bottom %d, top %d, num %d ExpSN %d\n",
buff->bottom, buff->top, num, buff->ExpSN));
return buff->ExpSN;
}
/*
* next_sernum:
* Return the current command serial number of the session
* and optionally increment it for the next query
*/
uint32_t
get_sernum(session_t *sess, pdu_t *pdu)
{
uint32_t sn;
KASSERT(mutex_owned(&sess->s_lock));
sn = sess->s_CmdSN;
if ((pdu->pdu_hdr.pduh_Opcode & OP_IMMEDIATE) == 0)
atomic_inc_32(&sess->s_CmdSN);
return sn;
}
/*
* sernum_in_window:
* Check whether serial number is in send window
*
*/
int
sernum_in_window(session_t *sess)
{
KASSERT(mutex_owned(&sess->s_lock));
return sn_a_le_b(sess->s_CmdSN, sess->s_MaxCmdSN);
}
/*
* window_size:
* Compute send window size
*/
int
window_size(session_t *sess, int limit)
{
uint32_t win;
KASSERT(mutex_owned(&sess->s_lock));
win = 0;
if (sn_a_le_b(sess->s_CmdSN, sess->s_MaxCmdSN))
win = sess->s_MaxCmdSN - sess->s_CmdSN + 1;
if (win > INT_MAX || win > limit)
win = limit;
return win;
}