/* $NetBSD: iscsi_rcv.c,v 1.27 2024/11/03 10:50:21 mlelstv Exp $ */

/* $NetBSD: iscsi_rcv.c,v 1.27 2024/11/03 10:50:21 mlelstv Exp $ */

/*-
* Copyright (c) 2004,2005,2006,2011 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/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

/*****************************************************************************/

/*
* my_soo_read:
* Replacement for soo_read with flag handling.
*
* Parameter:
* conn The connection
* u The uio descriptor
* flags Read flags
*
* Returns: 0 on success, else 1
*/

STATIC int
my_soo_read(connection_t *conn, struct uio *u, int flags)
{
struct socket *so;
int ret;
#ifdef ISCSI_DEBUG
size_t resid = u->uio_resid;
#endif

DEBC(conn, 99, ("soo_read req: %zu\n", resid));

rw_enter(&conn->c_sock_rw, RW_READER);
if (conn->c_sock == NULL) {
ret = EIO;
} else {
so = conn->c_sock->f_socket;
if (flags & MSG_WAITALL) {
flags &= ~MSG_WAITALL;
do {
int oresid = u->uio_resid;
ret = (*so->so_receive)(so, NULL, u,
NULL, NULL, &flags);
if (!ret && u->uio_resid == oresid)
break;
} while (!ret && u->uio_resid > 0);
} else {
ret = (*so->so_receive)(so, NULL, u,
NULL, NULL, &flags);
}
}

rw_exit(&conn->c_sock_rw);

if (ret || (flags != MSG_DONTWAIT && u->uio_resid)) {
DEBC(conn, 1, ("Read failed (ret: %d, req: %zu, out: %zu)\n",
ret, resid, u->uio_resid));
if (ret)
handle_connection_error(conn, ISCSI_STATUS_SOCKET_ERROR,
RECOVER_CONNECTION);
return 1;
}
return 0;
}

/*
* try_resynch_receive:
* Skip over everything in the socket's receive buffer, in the hope of
* ending up at the start of a new PDU.
*
* Parameter:
* conn The connection
*/

STATIC void
try_resynch_receive(connection_t *conn)
{
uint8_t buffer[64];
struct uio uio;
struct iovec io_vec;
int rc;

uio.uio_rw = UIO_READ;
UIO_SETUP_SYSSPACE(&uio);

do {
io_vec.iov_base = buffer;
uio.uio_iov = &io_vec;
uio.uio_iovcnt = 1;
uio.uio_resid = io_vec.iov_len = sizeof(buffer);

rc = my_soo_read(conn, &uio, MSG_DONTWAIT);
DEBC(conn, 9, ("try_resynch_receive: rc = %d, resid = %zu\n",
rc, uio.uio_resid));
} while (!rc && !uio.uio_resid);
}

/*
* ccb_from_itt
* Translate ITT into CCB pointer.
*
* Parameter:
* conn The connection
* itt The Initiator Task Tag
*
* Returns:
* Pointer to CCB, or NULL if ITT is not a valid CCB index.
*/

STATIC ccb_t *
ccb_from_itt(connection_t *conn, uint32_t itt)
{
ccb_t *ccb;
int cidx;

if (itt == 0xffffffff)
return NULL;

cidx = itt & 0xff;
if (cidx >= CCBS_PER_SESSION)
return NULL;

ccb = &conn->c_session->s_ccb[cidx];

if (ccb->ccb_ITT != itt) {
DEBC(conn, 0,
("ccb_from_itt: received invalid CCB itt %08x != %08x\n",
itt, ccb->ccb_ITT));
return NULL;
}

if (ccb->ccb_disp <= CCBDISP_BUSY) {
DEBC(conn, 0,
("ccb_from_itt: received CCB with invalid disp %d\n",
ccb->ccb_disp));
return NULL;
}

return ccb;
}

/*
* read_pdu_data:
* Initialize the uio structure for receiving everything after the
* header, including data (if present), and padding. Read the data.
*
* Parameter:
* pdu The PDU
* data Pointer to data (may be NULL for auto-allocation)
* offset The offset into the data pointer
*
* Returns: 0 on success
* 1 if an error occurs during read
* -1 if the data digest was incorrect (PDU must be ignored)
*/

STATIC int
read_pdu_data(pdu_t *pdu, uint8_t *data, uint32_t offset)
{
static uint8_t pad_bytes[4];
uint32_t len, digest;
struct uio *uio;
int i, pad;
connection_t *conn = pdu->pdu_connection;

DEB(15, ("read_pdu_data: data segment length = %d\n",
ntoh3(pdu->pdu_hdr.pduh_DataSegmentLength)));
if (!(len = ntoh3(pdu->pdu_hdr.pduh_DataSegmentLength))) {
return 0;
}
pad = len & 0x03;
if (pad) {
pad = 4 - pad;
}

KASSERT(data != NULL || offset == 0);

if (data == NULL) {
/*
* NOTE: Always allocate 2 extra bytes when reading temp data,
* since temp data is mostly used for received text, and we can
* make sure there's a double zero at the end of the data to mark EOF.
*/
if ((data = (uint8_t *) malloc(len + 2, M_TEMP, M_WAITOK)) == NULL) {
DEBOUT(("ran out of mem on receive\n"));
handle_connection_error(pdu->pdu_connection,
ISCSI_STATUS_NO_RESOURCES, LOGOUT_SESSION);
return 1;
}
pdu->pdu_temp_data = data;
pdu->pdu_temp_data_len = len;
}

pdu->pdu_io_vec[0].iov_base = data + offset;
pdu->pdu_io_vec[0].iov_len = len;

uio = &pdu->pdu_uio;

uio->uio_iov = pdu->pdu_io_vec;
uio->uio_iovcnt = 1;
uio->uio_rw = UIO_READ;
uio->uio_resid = len;
UIO_SETUP_SYSSPACE(uio);

if (pad) {
uio->uio_iovcnt++;
uio->uio_iov[1].iov_base = pad_bytes;
uio->uio_iov[1].iov_len = pad;
uio->uio_resid += pad;
}

if (conn->c_DataDigest) {
i = uio->uio_iovcnt++;
pdu->pdu_io_vec[i].iov_base = &pdu->pdu_data_digest;
pdu->pdu_io_vec[i].iov_len = 4;
uio->uio_resid += 4;
}

/* get the data */
if (my_soo_read(conn, &pdu->pdu_uio, MSG_WAITALL) != 0) {
return 1;
}
if (conn->c_DataDigest) {
digest = gen_digest_2(data, len, pad_bytes, pad);

if (digest != pdu->pdu_data_digest) {
DEBOUT(("Data Digest Error: comp = %08x, rx = %08x\n",
digest, pdu->pdu_data_digest));
switch (pdu->pdu_hdr.pduh_Opcode & OPCODE_MASK) {
case TOP_SCSI_Response:
case TOP_Text_Response:
send_snack(pdu->pdu_connection, pdu, NULL, SNACK_STATUS_NAK);
break;

case TOP_SCSI_Data_in:
send_snack(pdu->pdu_connection, pdu, NULL, SNACK_DATA_NAK);
break;

default:
/* ignore all others */
break;
}
return -1;
}
}
return 0;
}

/*
* collect_text_data
* Handle text continuation in login and text response PDUs
*
* Parameter:
* pdu The received PDU
* req_CCB The CCB associated with the original request
*
* Returns: -1 if continue flag is set
* 0 if text is complete
* +1 if an error occurred (out of resources)
*/
STATIC int
collect_text_data(pdu_t *pdu, ccb_t *req_ccb)
{

if (req_ccb->ccb_text_data) {
int nlen;
uint8_t *newp;

nlen = req_ccb->ccb_text_len + pdu->pdu_temp_data_len;
/* Note: allocate extra 2 bytes for text terminator */
if ((newp = malloc(nlen + 2, M_TEMP, M_WAITOK)) == NULL) {
DEBOUT(("Collect Text Data: Out of Memory, ccb = %p\n", req_ccb));
req_ccb->ccb_status = ISCSI_STATUS_NO_RESOURCES;
/* XXX where is CCB freed? */
return 1;
}
memcpy(newp, req_ccb->ccb_text_data, req_ccb->ccb_text_len);
memcpy(&newp[req_ccb->ccb_text_len], pdu->pdu_temp_data, pdu->pdu_temp_data_len);

free(req_ccb->ccb_text_data, M_TEMP);
free(pdu->pdu_temp_data, M_TEMP);

req_ccb->ccb_text_data = NULL;
pdu->pdu_temp_data = newp;
pdu->pdu_temp_data_len = nlen;
}

if (pdu->pdu_hdr.pduh_Flags & FLAG_CONTINUE) {
req_ccb->ccb_text_data = pdu->pdu_temp_data;
req_ccb->ccb_text_len = pdu->pdu_temp_data_len;
pdu->pdu_temp_data = NULL;

acknowledge_text(req_ccb->ccb_connection, pdu, req_ccb);
return -1;
}
return 0;
}

/*
* check_StatSN
* Check received vs. expected StatSN
*
* Parameter:
* conn The connection
* nw_sn The received StatSN in network byte order
* ack Acknowledge this SN if TRUE
*/

STATIC int
check_StatSN(connection_t *conn, uint32_t nw_sn, bool ack)
{
int rc;
uint32_t sn = ntohl(nw_sn);

rc = add_sernum(&conn->c_StatSN_buf, sn);

if (ack)
ack_sernum(&conn->c_StatSN_buf, sn);

if (rc != 1) {
if (rc == 0) {
DEBOUT(("Duplicate PDU, ExpSN %d, Recvd: %d\n",
conn->c_StatSN_buf.ExpSN, sn));
return -1;
}

if (rc < 0) {
DEBOUT(("Excessive outstanding Status PDUs, ExpSN %d, Recvd: %d\n",
conn->c_StatSN_buf.ExpSN, sn));
handle_connection_error(conn, ISCSI_STATUS_PDUS_LOST,
RECOVER_CONNECTION);
return rc;
}

DEBOUT(("Missing Status PDUs: First %d, num: %d\n",
conn->c_StatSN_buf.ExpSN, rc - 1));
if (conn->c_state == ST_FULL_FEATURE &&
conn->c_session->s_ErrorRecoveryLevel) {
snack_missing(conn, NULL, SNACK_STATUS_NAK,
conn->c_StatSN_buf.ExpSN, rc - 1);
} else {
DEBOUT(("StatSN killing connection (State = %d, "
"ErrorRecoveryLevel = %d)\n",
conn->c_state, conn->c_session->s_ErrorRecoveryLevel));
handle_connection_error(conn, ISCSI_STATUS_PDUS_LOST,
RECOVER_CONNECTION);
return -1;
}
}
return 0;
}

/*
* check_CmdSN
* Check received vs. expected CmdSN
*
* Parameter:
* conn The connection
* nw_sn The received ExpCmdSN in network byte order
*/

STATIC void
check_CmdSN(connection_t *conn, uint32_t nw_sn)
{
uint32_t sn = ntohl(nw_sn);
ccb_t *ccb, *nxt;

TAILQ_FOREACH_SAFE(ccb, &conn->c_ccbs_waiting, ccb_chain, nxt) {
DEBC(conn, 10,
("CheckCmdSN - CmdSN=%d, ExpCmdSn=%d, waiting=%p, flags=%x\n",
ccb->ccb_CmdSN, sn, ccb->ccb_pdu_waiting, ccb->ccb_flags));
if (ccb->ccb_pdu_waiting != NULL &&
sn_a_lt_b(sn, ccb->ccb_CmdSN) &&
!(ccb->ccb_flags & CCBF_GOT_RSP)) {
DEBC(conn, 1, ("CheckCmdSN resending - CmdSN=%d, ExpCmdSn=%d\n",
ccb->ccb_CmdSN, sn));

ccb->ccb_total_tries++;

if (++ccb->ccb_num_timeouts > MAX_CCB_TIMEOUTS ||
ccb->ccb_total_tries > MAX_CCB_TRIES) {
handle_connection_error(conn,
ISCSI_STATUS_TIMEOUT,
(ccb->ccb_total_tries <= MAX_CCB_TRIES)
? RECOVER_CONNECTION
: LOGOUT_CONNECTION);
break;
} else {
resend_pdu(ccb);
}
}

/*
* The target can respond to a NOP-In before subsequent
* commands are processed. So our CmdSN can exceed the
* returned ExpCmdSN by the number of commands that are
* in flight. Adjust the expected value accordingly.
*/
sn++;
}
}

/*
* receive_login_pdu
* Handle receipt of a login response PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_login_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
int rc;

DEBC(conn, 9, ("Received Login Response PDU, op=%x, flags=%x, sn=%u\n",
pdu->pdu_hdr.pduh_Opcode, pdu->pdu_hdr.pduh_Flags,
ntohl(pdu->pdu_hdr.pduh_p.login_rsp.StatSN)));

if (req_ccb == NULL) {
/* Duplicate?? */
DEBOUT(("Received duplicate login response (no associated CCB)\n"));
return -1;
}

if (pdu->pdu_hdr.pduh_p.login_rsp.StatusClass) {
DEBC(conn, 1, ("Login problem - Class = %x, Detail = %x\n",
pdu->pdu_hdr.pduh_p.login_rsp.StatusClass,
pdu->pdu_hdr.pduh_p.login_rsp.StatusDetail));
wake_ccb(req_ccb, ISCSI_STATUS_LOGIN_FAILED);
return 0;
}

if (!conn->c_StatSN_buf.next_sn) {
conn->c_StatSN_buf.next_sn = conn->c_StatSN_buf.ExpSN =
ntohl(pdu->pdu_hdr.pduh_p.login_rsp.StatSN) + 1;
} else if (check_StatSN(conn, pdu->pdu_hdr.pduh_p.login_rsp.StatSN, TRUE))
return -1;

if (pdu->pdu_temp_data_len) {
if ((rc = collect_text_data(pdu, req_ccb)) != 0)
return max(rc, 0);
}

negotiate_login(conn, pdu, req_ccb);

/* negotiate_login will decide whether login is complete or not */
return 0;
}

/*
* receive_text_response_pdu
* Handle receipt of a text response PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_text_response_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
int rc;

DEBC(conn, 9, ("Received Text Response PDU, op=%x, flags=%x\n",
pdu->pdu_hdr.pduh_Opcode, pdu->pdu_hdr.pduh_Flags));

if (check_StatSN(conn, pdu->pdu_hdr.pduh_p.text_rsp.StatSN, TRUE)) {
return -1;
}
if (req_ccb == NULL) {
DEBOUT(("Received unsolicited text response\n"));
handle_connection_error(conn, ISCSI_STATUS_TARGET_ERROR,
LOGOUT_CONNECTION);
return -1;
}

if (req_ccb->ccb_pdu_waiting != NULL) {
ccb_timeout_start(req_ccb, COMMAND_TIMEOUT);
req_ccb->ccb_num_timeouts = 0;
}

if ((rc = collect_text_data(pdu, req_ccb)) != 0) {
return max(0, rc);
}
negotiate_text(conn, pdu, req_ccb);

return 0;
}

/*
* receive_logout_pdu
* Handle receipt of a logout response PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_logout_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
bool otherconn;
uint8_t response;
uint32_t status;

otherconn = (req_ccb != NULL) ? (req_ccb->ccb_flags & CCBF_OTHERCONN) != 0 : 1;
response = pdu->pdu_hdr.pduh_OpcodeSpecific [0];
DEBC(conn, 1,
("Received Logout PDU - CCB = %p, otherconn=%d, response=%d\n",
req_ccb, otherconn, response));

if (req_ccb == NULL)
return 0;

if (otherconn && check_StatSN(conn, pdu->pdu_hdr.pduh_p.logout_rsp.StatSN, TRUE))
return -1;

switch (response) {
case 0:
status = ISCSI_STATUS_SUCCESS;
break;
case 1:
status = ISCSI_STATUS_LOGOUT_CID_NOT_FOUND;
break;
case 2:
status = ISCSI_STATUS_LOGOUT_RECOVERY_NS;
break;
default:
status = ISCSI_STATUS_LOGOUT_ERROR;
break;
}

if (conn->c_session->s_ErrorRecoveryLevel >= 2 && response != 1) {
connection_t *refconn = (otherconn) ? req_ccb->ccb_par : conn;

refconn->c_Time2Wait = ntohs(pdu->pdu_hdr.pduh_p.logout_rsp.Time2Wait);
refconn->c_Time2Retain = ntohs(pdu->pdu_hdr.pduh_p.logout_rsp.Time2Retain);
}

wake_ccb(req_ccb, status);

mutex_enter(&conn->c_lock);
if (!otherconn && conn->c_state == ST_LOGOUT_SENT) {
conn->c_terminating = ISCSI_STATUS_LOGOUT;
conn->c_state = ST_SETTLING;
conn->c_loggedout = (response) ? LOGOUT_FAILED : LOGOUT_SUCCESS;
mutex_exit(&conn->c_lock);

connection_timeout_stop(conn);

/* let send thread take over next step of cleanup */
mutex_enter(&conn->c_lock);
cv_broadcast(&conn->c_conn_cv);
}
mutex_exit(&conn->c_lock);

return !otherconn;
}

/*
* receive_data_in_pdu
* Handle receipt of a data in PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_data_in_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
uint32_t dsl, sn;
bool done;
int rc;

dsl = ntoh3(pdu->pdu_hdr.pduh_DataSegmentLength);

if (req_ccb == NULL || !req_ccb->ccb_data_in || !req_ccb->ccb_data_len) {
DEBOUT(("Received Data In, but req_ccb not waiting for it, ignored\n"));
return 0;
}
req_ccb->ccb_flags |= CCBF_GOT_RSP;

if (req_ccb->ccb_pdu_waiting != NULL) {
ccb_timeout_start(req_ccb, COMMAND_TIMEOUT);
req_ccb->ccb_num_timeouts = 0;
}

sn = ntohl(pdu->pdu_hdr.pduh_p.data_in.DataSN);

if ((rc = add_sernum(&req_ccb->ccb_DataSN_buf, sn)) != 1) {
if (!rc) {
return -1;
}
if (rc < 0) {
DEBOUT(("Excessive outstanding Data PDUs\n"));
handle_connection_error(req_ccb->ccb_connection,
ISCSI_STATUS_PDUS_LOST, LOGOUT_CONNECTION);
return -1;
}
DEBOUT(("Missing Data PDUs: First %d, num: %d\n",
req_ccb->ccb_DataSN_buf.ExpSN, rc - 1));

if (conn->c_state == ST_FULL_FEATURE &&
conn->c_session->s_ErrorRecoveryLevel) {
snack_missing(req_ccb->ccb_connection, req_ccb,
SNACK_DATA_NAK, req_ccb->ccb_DataSN_buf.ExpSN,
rc - 1);
} else {
DEBOUT(("Killing connection (State=%d, ErrorRecoveryLevel=%d)\n",
conn->c_state, conn->c_session->s_ErrorRecoveryLevel));
handle_connection_error(conn, ISCSI_STATUS_PDUS_LOST,
LOGOUT_CONNECTION);
return -1;
}
}

ack_sernum(&req_ccb->ccb_DataSN_buf, sn);

req_ccb->ccb_xfer_len += dsl;

if ((pdu->pdu_hdr.pduh_Flags & FLAG_ACK) && conn->c_session->s_ErrorRecoveryLevel)
send_snack(conn, pdu, req_ccb, SNACK_DATA_ACK);

done = sn_empty(&req_ccb->ccb_DataSN_buf);

if (pdu->pdu_hdr.pduh_Flags & FLAG_STATUS) {
DEBC(conn, 10, ("Rx Data In %d, done = %d\n",
req_ccb->ccb_CmdSN, done));

req_ccb->ccb_flags |= CCBF_COMPLETE;
/* successful transfer, reset recover count */
conn->c_recover = 0;

if (done)
wake_ccb(req_ccb, ISCSI_STATUS_SUCCESS);
if (check_StatSN(conn, pdu->pdu_hdr.pduh_p.data_in.StatSN, done))
return -1;

} else if (done && (req_ccb->ccb_flags & CCBF_COMPLETE)) {
wake_ccb(req_ccb, ISCSI_STATUS_SUCCESS);
}
/* else wait for command response */

return 0;
}

/*
* receive_r2t_pdu
* Handle receipt of a R2T PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_r2t_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{

DEBC(conn, 10, ("Received R2T PDU - CCB = %p\n", req_ccb));

if (req_ccb != NULL) {
if (req_ccb->ccb_pdu_waiting != NULL) {
ccb_timeout_start(req_ccb, COMMAND_TIMEOUT);
req_ccb->ccb_num_timeouts = 0;
}
send_data_out(conn, pdu, req_ccb, CCBDISP_NOWAIT, TRUE);
}

return 0;
}

/*
* receive_command_response_pdu
* Handle receipt of a command response PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_command_response_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
int len, rc;
bool done;
uint32_t status;

/* Read any provided data */
if (pdu->pdu_temp_data_len && req_ccb != NULL && req_ccb->ccb_sense_len_req) {
len = min(req_ccb->ccb_sense_len_req,
ntohs(*((uint16_t *) pdu->pdu_temp_data)));
memcpy(req_ccb->ccb_sense_ptr, ((uint16_t *) pdu->pdu_temp_data) + 1,
len);
req_ccb->ccb_sense_len_got = len;
}

if (req_ccb == NULL) {
/* Assume duplicate... */
DEBOUT(("Possibly duplicate command response (no associated CCB)\n"));
return -1;
}

if (req_ccb->ccb_flags & CCBF_COMPLETE) {
DEBOUT(("Possibly duplicate command response (tagged as COMPLETE)\n"));
return -1;
}

if (req_ccb->ccb_pdu_waiting != NULL) {
ccb_timeout_start(req_ccb, COMMAND_TIMEOUT);
req_ccb->ccb_num_timeouts = 0;
}

req_ccb->ccb_flags |= CCBF_COMPLETE;
conn->c_recover = 0; /* successful transfer, reset recover count */

if (pdu->pdu_hdr.pduh_OpcodeSpecific[0]) { /* Response */
status = ISCSI_STATUS_TARGET_FAILURE;
} else {
switch (pdu->pdu_hdr.pduh_OpcodeSpecific[1]) { /* Status */
case 0x00:
status = ISCSI_STATUS_SUCCESS;
break;

case 0x02:
status = ISCSI_STATUS_CHECK_CONDITION;
break;

case 0x08:
status = ISCSI_STATUS_TARGET_BUSY;
break;

default:
status = ISCSI_STATUS_TARGET_ERROR;
break;
}
}

if (pdu->pdu_hdr.pduh_Flags & (FLAG_OVERFLOW | FLAG_UNDERFLOW))
req_ccb->ccb_residual = ntohl(pdu->pdu_hdr.pduh_p.response.ResidualCount);

done = status || sn_empty(&req_ccb->ccb_DataSN_buf);

DEBC(conn, 10, ("Rx Response: CmdSN %d, rsp = %x, status = %x\n",
req_ccb->ccb_CmdSN,
pdu->pdu_hdr.pduh_OpcodeSpecific[0],
pdu->pdu_hdr.pduh_OpcodeSpecific[1]));

rc = check_StatSN(conn, pdu->pdu_hdr.pduh_p.response.StatSN, done);

if (done)
wake_ccb(req_ccb, status);

return rc;
}

/*
* receive_asynch_pdu
* Handle receipt of an asynchronous message PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
*/

STATIC int
receive_asynch_pdu(connection_t *conn, pdu_t *pdu)
{

DEBOUT(("Received Asynch PDU, Event %d\n", pdu->pdu_hdr.pduh_p.asynch.AsyncEvent));

switch (pdu->pdu_hdr.pduh_p.asynch.AsyncEvent) {
case 0: /* SCSI Asynch event. Don't know what to do with it... */
break;

case 1: /* Target requests logout. */
if (conn->c_session->s_active_connections > 1) {
kill_connection(conn, ISCSI_STATUS_TARGET_LOGOUT,
LOGOUT_CONNECTION, FALSE);
} else {
kill_session(conn->c_session->s_id,
ISCSI_STATUS_TARGET_LOGOUT, LOGOUT_SESSION,
FALSE);
}
break;

case 2: /* Target is dropping connection */
conn = find_connection(conn->c_session,
ntohs(pdu->pdu_hdr.pduh_p.asynch.Parameter1));
if (conn != NULL) {
conn->c_Time2Wait =
ntohs(pdu->pdu_hdr.pduh_p.asynch.Parameter2);
conn->c_Time2Retain =
ntohs(pdu->pdu_hdr.pduh_p.asynch.Parameter3);
kill_connection(conn, ISCSI_STATUS_TARGET_DROP,
NO_LOGOUT, TRUE);
}
break;

case 3: /* Target is dropping all connections of session */
conn->c_session->s_DefaultTime2Wait =
ntohs(pdu->pdu_hdr.pduh_p.asynch.Parameter2);
conn->c_session->s_DefaultTime2Retain =
ntohs(pdu->pdu_hdr.pduh_p.asynch.Parameter3);
kill_session(conn->c_session->s_id,
ISCSI_STATUS_TARGET_DROP, NO_LOGOUT,
TRUE);
break;

case 4: /* Target requests parameter negotiation */
start_text_negotiation(conn);
break;

default:
/* ignore */
break;
}
return 0;
}

/*
* receive_reject_pdu
* Handle receipt of a reject PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
*/

STATIC int
receive_reject_pdu(connection_t *conn, pdu_t *pdu)
{
pdu_header_t *hpdu;
ccb_t *req_ccb;
uint32_t status;

DEBOUT(("Received Reject PDU, reason = %x, data_len = %d\n",
pdu->pdu_hdr.pduh_OpcodeSpecific[0], pdu->pdu_temp_data_len));

if (pdu->pdu_temp_data_len >= BHS_SIZE) {
hpdu = (pdu_header_t *) pdu->pdu_temp_data;
req_ccb = ccb_from_itt(conn, hpdu->pduh_InitiatorTaskTag);

DEBC(conn, 9, ("Reject PDU ITT (ccb)= %x (%p)\n",
hpdu->pduh_InitiatorTaskTag, req_ccb));
if (!req_ccb) {
return 0;
}
switch (pdu->pdu_hdr.pduh_OpcodeSpecific[0]) {
case REJECT_DIGEST_ERROR:
/* don't retransmit data out */
if ((hpdu->pduh_Opcode & OPCODE_MASK) == IOP_SCSI_Data_out)
return 0;
resend_pdu(req_ccb);
return 0;

case REJECT_IMMED_COMMAND:
case REJECT_LONG_OPERATION:
resend_pdu(req_ccb);
return 0;

case REJECT_SNACK:
case REJECT_PROTOCOL_ERROR:
status = ISCSI_STATUS_PROTOCOL_ERROR;
break;

case REJECT_CMD_NOT_SUPPORTED:
status = ISCSI_STATUS_CMD_NOT_SUPPORTED;
break;

case REJECT_INVALID_PDU_FIELD:
status = ISCSI_STATUS_PDU_ERROR;
break;

default:
status = ISCSI_STATUS_GENERAL_ERROR;
break;
}

wake_ccb(req_ccb, status);
handle_connection_error(conn, ISCSI_STATUS_PROTOCOL_ERROR,
LOGOUT_CONNECTION);
}
return 0;
}

/*
* receive_task_management_pdu
* Handle receipt of a task management PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_task_management_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
uint32_t status;

DEBC(conn, 2, ("Received Task Management PDU, response %d, req_ccb %p\n",
pdu->pdu_hdr.pduh_OpcodeSpecific[0], req_ccb));

if (req_ccb != NULL) {
switch (pdu->pdu_hdr.pduh_OpcodeSpecific[0]) { /* Response */
case 0:
status = ISCSI_STATUS_SUCCESS;
break;
case 1:
status = ISCSI_STATUS_TASK_NOT_FOUND;
break;
case 2:
status = ISCSI_STATUS_LUN_NOT_FOUND;
break;
case 3:
status = ISCSI_STATUS_TASK_ALLEGIANT;
break;
case 4:
status = ISCSI_STATUS_CANT_REASSIGN;
break;
case 5:
status = ISCSI_STATUS_FUNCTION_UNSUPPORTED;
break;
case 6:
status = ISCSI_STATUS_FUNCTION_NOT_AUTHORIZED;
break;
case 255:
status = ISCSI_STATUS_FUNCTION_REJECTED;
break;
default:
status = ISCSI_STATUS_UNKNOWN_REASON;
break;
}
wake_ccb(req_ccb, status);
}

check_StatSN(conn, pdu->pdu_hdr.pduh_p.task_rsp.StatSN, TRUE);

return 0;
}

/*
* receive_nop_in_pdu
* Handle receipt of a Nop-In PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
* req_CCB The CCB associated with the original request (if any)
*/

STATIC int
receive_nop_in_pdu(connection_t *conn, pdu_t *pdu, ccb_t *req_ccb)
{
DEBC(conn, 10,
("Received NOP_In PDU, req_ccb=%p, ITT=%x, TTT=%x, StatSN=%u\n",
req_ccb, pdu->pdu_hdr.pduh_InitiatorTaskTag,
pdu->pdu_hdr.pduh_p.nop_in.TargetTransferTag,
ntohl(pdu->pdu_hdr.pduh_p.nop_in.StatSN)));

if (pdu->pdu_hdr.pduh_InitiatorTaskTag == 0xffffffff) {
/* this is a target ping - respond with a pong */
if (pdu->pdu_hdr.pduh_p.nop_in.TargetTransferTag != 0xffffffff)
send_nop_out(conn, pdu);

/*
Any receive resets the connection timeout, but we got a ping, which
means that it's likely the other side was waiting for something to
happen on the connection. If we aren't idle, send a ping right
away to synch counters (don't synch on this ping because other
PDUs may be on the way).
*/
if (TAILQ_FIRST(&conn->c_ccbs_waiting) != NULL)
send_nop_out(conn, NULL);
} else if (req_ccb != NULL) {
/* this is a solicited ping, check CmdSN for lost commands */
/* and advance StatSN */
check_CmdSN(conn, pdu->pdu_hdr.pduh_p.nop_in.ExpCmdSN);

wake_ccb(req_ccb, ISCSI_STATUS_SUCCESS);

check_StatSN(conn, pdu->pdu_hdr.pduh_p.nop_in.StatSN, TRUE);
} else {
DEBC(conn, 0, ("Received unsolicted NOP_In, itt=%08x\n",
pdu->pdu_hdr.pduh_InitiatorTaskTag));
}

return 0;
}

/*
* receive_pdu
* Get parameters, call the appropriate handler for a received PDU.
*
* Parameter:
* conn The connection
* pdu The PDU
*
* Returns: 0 on success, nonzero if the connection is broken.
*/

STATIC int
receive_pdu(connection_t *conn, pdu_t *pdu)
{
ccb_t *req_ccb;
int rc;
uint32_t MaxCmdSN, ExpCmdSN, digest;
session_t *sess = conn->c_session;

if (conn->c_HeaderDigest) {
digest = gen_digest(&pdu->pdu_hdr, BHS_SIZE);
if (digest != pdu->pdu_hdr.pduh_HeaderDigest) {
DEBOUT(("Header Digest Error: comp = %08x, rx = %08x\n",
digest, pdu->pdu_hdr.pduh_HeaderDigest));
/* try to skip to next PDU */
try_resynch_receive(conn);
free_pdu(pdu);
return 0;
}
}

DEBC(conn, 10, ("Received PDU StatSN=%u, ExpCmdSN=%u MaxCmdSN=%u ExpDataSN=%u\n",
ntohl(pdu->pdu_hdr.pduh_p.response.StatSN),
ntohl(pdu->pdu_hdr.pduh_p.response.ExpCmdSN),
ntohl(pdu->pdu_hdr.pduh_p.response.MaxCmdSN),
ntohl(pdu->pdu_hdr.pduh_p.response.ExpDataSN)));

req_ccb = ccb_from_itt(conn, pdu->pdu_hdr.pduh_InitiatorTaskTag);

if (req_ccb != NULL && req_ccb->ccb_data_in && req_ccb->ccb_data_len &&
(pdu->pdu_hdr.pduh_Opcode & OPCODE_MASK) == TOP_SCSI_Data_in) {
uint32_t dsl, offset;

dsl = ntoh3(pdu->pdu_hdr.pduh_DataSegmentLength);
offset = ntohl(pdu->pdu_hdr.pduh_p.data_in.BufferOffset);

if ((offset + dsl) > req_ccb->ccb_data_len) {
DEBOUT(("Received more data than requested (len %d, offset %d)\n",
dsl, offset));
handle_connection_error(conn, ISCSI_STATUS_TARGET_ERROR, NO_LOGOUT);
return 1;
}
DEBC(conn, 10,
("Received Data in PDU - CCB = %p, Datalen = %d, Offset = %d\n",
req_ccb, dsl, offset));

rc = read_pdu_data(pdu, req_ccb->ccb_data_ptr, offset);
} else {
rc = read_pdu_data(pdu, NULL, 0);
}
if (!rc && (conn->c_state <= ST_WINDING_DOWN ||
(pdu->pdu_hdr.pduh_Opcode & OPCODE_MASK) == TOP_Logout_Response)) {

switch (pdu->pdu_hdr.pduh_Opcode & OPCODE_MASK) {
case TOP_NOP_In:
rc = receive_nop_in_pdu(conn, pdu, req_ccb);
break;

case TOP_SCSI_Response:
rc = receive_command_response_pdu(conn, pdu, req_ccb);
break;

case TOP_SCSI_Task_Management:
rc = receive_task_management_pdu(conn, pdu, req_ccb);
break;

case TOP_Login_Response:
rc = receive_login_pdu(conn, pdu, req_ccb);
break;

case TOP_Text_Response:
rc = receive_text_response_pdu(conn, pdu, req_ccb);
break;

case TOP_SCSI_Data_in:
rc = receive_data_in_pdu(conn, pdu, req_ccb);
break;

case TOP_Logout_Response:
rc = receive_logout_pdu(conn, pdu, req_ccb);
break;

case TOP_R2T:
rc = receive_r2t_pdu(conn, pdu, req_ccb);
break;

case TOP_Asynchronous_Message:
rc = receive_asynch_pdu(conn, pdu);
break;

case TOP_Reject:
rc = receive_reject_pdu(conn, pdu);
break;

default:
DEBOUT(("Received Invalid Opcode %x\n", pdu->pdu_hdr.pduh_Opcode));
try_resynch_receive(conn);
rc = -1;
break;
}
}

free_pdu(pdu);
if (rc)
return rc;

/* MaxCmdSN and ExpCmdSN are in the same place in all received PDUs */
ExpCmdSN = ntohl(pdu->pdu_hdr.pduh_p.nop_in.ExpCmdSN);
MaxCmdSN = ntohl(pdu->pdu_hdr.pduh_p.nop_in.MaxCmdSN);

/* received a valid frame, reset timeout */
conn->c_num_timeouts = 0;
if ((pdu->pdu_hdr.pduh_Opcode & OPCODE_MASK) == TOP_NOP_In &&
TAILQ_EMPTY(&conn->c_ccbs_waiting))
connection_timeout_start(conn, conn->c_idle_timeout_val);
else
connection_timeout_start(conn, CONNECTION_TIMEOUT);

/* Update session window */
mutex_enter(&sess->s_lock);
if (sn_a_le_b(ExpCmdSN - 1, MaxCmdSN)) {
if (sn_a_lt_b(sess->s_ExpCmdSN, ExpCmdSN))
sess->s_ExpCmdSN = ExpCmdSN;
if (sn_a_lt_b(sess->s_MaxCmdSN, MaxCmdSN))
sess->s_MaxCmdSN = MaxCmdSN;
}
mutex_exit(&sess->s_lock);

return 0;
}

/*****************************************************************************/

/*
* iscsi_receive_thread
* Per connection thread handling receive data.
*
* Parameter:
* conn The connection
*/

void
iscsi_rcv_thread(void *par)
{
connection_t *conn = (connection_t *) par;
pdu_t *pdu;
size_t hlen;

do {
while (!conn->c_terminating) {
pdu = get_pdu(conn, TRUE);
if (pdu == NULL) {
KASSERT(conn->c_terminating);
break;
}

pdu->pdu_uio.uio_iov = pdu->pdu_io_vec;
UIO_SETUP_SYSSPACE(&pdu->pdu_uio);
pdu->pdu_uio.uio_iovcnt = 1;
pdu->pdu_uio.uio_rw = UIO_READ;

pdu->pdu_io_vec[0].iov_base = &pdu->pdu_hdr;
hlen = (conn->c_HeaderDigest) ? BHS_SIZE + 4 : BHS_SIZE;
pdu->pdu_io_vec[0].iov_len = hlen;
pdu->pdu_uio.uio_resid = hlen;

DEBC(conn, 99, ("Receive thread waiting for data\n"));
if (my_soo_read(conn, &pdu->pdu_uio, MSG_WAITALL)) {
free_pdu(pdu);
break;
}
/* Check again for header digest */
/* (it may have changed during the wait) */
if (hlen == BHS_SIZE && conn->c_HeaderDigest) {
pdu->pdu_uio.uio_iov = pdu->pdu_io_vec;
pdu->pdu_uio.uio_iovcnt = 1;
pdu->pdu_io_vec[0].iov_base = &pdu->pdu_hdr.pduh_HeaderDigest;
pdu->pdu_io_vec[0].iov_len = 4;
pdu->pdu_uio.uio_resid = 4;
if (my_soo_read(conn, &pdu->pdu_uio, MSG_WAITALL)) {
free_pdu(pdu);
break;
}
}

if (receive_pdu(conn, pdu) > 0) {
break;
}
}
mutex_enter(&conn->c_lock);
if (!conn->c_destroy) {
cv_timedwait(&conn->c_idle_cv, &conn->c_lock, CONNECTION_IDLE_TIMEOUT);
}
mutex_exit(&conn->c_lock);
} while (!conn->c_destroy);

conn->c_rcvproc = NULL;
DEBC(conn, 5, ("Receive thread exits\n"));
kthread_exit(0);
}