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[iscsi] Accept NOP-In PDUs sent by the target 

Some iSCSI targets (observed with a Synology DS207+ NAS) send
unsolicited NOP-Ins to the initiator.  RFC 3720 is remarkably unclear
and possibly self-contradictory on how NOPs are supposed to work, but
it seems as though we can legitimately just ignore any unsolicited
NOP-In PDU.

Reported-by: Marc Lecuyer <marc@maxiscreen.com>
Originally-implemented-by: Thomas Miletich <thomas.miletich@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/1/head
Michael Brown 2011-02-24 13:22:20 +00:00
parent 030e5a064e
commit 711df439df
2 changed files with 84 additions and 0 deletions
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34
src/include/ipxe/iscsi.h
View File

@ -93,6 +93,9 @@ struct iscsi_bhs_common {
/** iSCSI tag magic marker */
#define ISCSI_TAG_MAGIC 0x18ae0000
/** iSCSI reserved tag value */
#define ISCSI_TAG_RESERVED 0xffffffff
/**
* iSCSI basic header segment common request fields
*
@ -455,6 +458,36 @@ struct iscsi_bhs_r2t {
/** R2T opcode */
#define ISCSI_OPCODE_R2T 0x31
/**
* iSCSI NOP-In basic header segment
*
*/
struct iscsi_nop_in {
/** Opcode */
uint8_t opcode;
/** Reserved */
uint8_t reserved_a[3];
/** Segment lengths */
union iscsi_segment_lengths lengths;
/** Logical Unit Number */
struct scsi_lun lun;
/** Initiator Task Tag */
uint32_t itt;
/** Target Transfer Tag */
uint32_t ttt;
/** Status sequence number */
uint32_t statsn;
/** Expected command sequence number */
uint32_t expcmdsn;
/** Maximum command sequence number */
uint32_t maxcmdsn;
/** Reserved */
uint8_t reserved_b[12];
};
/** NOP-In opcode */
#define ISCSI_OPCODE_NOP_IN 0x20
/**
* An iSCSI basic header segment
*/
@ -468,6 +501,7 @@ union iscsi_bhs {
struct iscsi_bhs_data_in data_in;
struct iscsi_bhs_data_out data_out;
struct iscsi_bhs_r2t r2t;
struct iscsi_nop_in nop_in;
unsigned char bytes[ sizeof ( struct iscsi_bhs_common ) ];
};

50
src/net/tcp/iscsi.c
View File

@ -123,6 +123,10 @@ FEATURE ( FEATURE_PROTOCOL, "iSCSI", DHCP_EB_FEATURE_ISCSI, 1 );
__einfo_error ( EINFO_EPROTO_INVALID_CHAP_RESPONSE )
#define EINFO_EPROTO_INVALID_CHAP_RESPONSE \
__einfo_uniqify ( EINFO_EPROTO, 0x04, "Invalid CHAP response" )
#define EPROTO_INVALID_NOP_IN \
__einfo_error ( EINFO_EPROTO_INVALID_NOP_IN )
#define EINFO_EPROTO_INVALID_NOP_IN \
__einfo_uniqify ( EINFO_EPROTO, 0x05, "Invalid NOP-In received" )
/** iSCSI initiator name (explicitly specified) */
static char *iscsi_explicit_initiator_iqn;
@ -589,6 +593,50 @@ static int iscsi_tx_data_out ( struct iscsi_session *iscsi ) {
return xfer_deliver_iob ( &iscsi->socket, iobuf );
}
/**
* Receive data segment of an iSCSI NOP-In
*
* @v iscsi iSCSI session
* @v data Received data
* @v len Length of received data
* @v remaining Data remaining after this data
* @ret rc Return status code
*/
static int iscsi_rx_nop_in ( struct iscsi_session *iscsi,
const void *data __unused, size_t len __unused,
size_t remaining __unused ) {
struct iscsi_nop_in *nop_in = &iscsi->rx_bhs.nop_in;
DBGC2 ( iscsi, "iSCSI %p received NOP-In\n", iscsi );
/* RFC 3720 section 10.19 states that "when a target sends a
* NOP-In that is not a response to a Nop-Out received from
* the initiator, the Initiator Task Tag MUST be set to
* 0xffffffff", and section 10.18 states that "upon receipt of
* a NOP-In with the Target Transfer Tag set to a valid value
* (not the reserved 0xffffffff), the initiator MUST respond
* with a NOP-Out". Since we never send unsolicited NOP-Outs,
* my reading of this is that we can handle all permitted
* NOP-Ins (which must have ITT set to 0xffffffff) by simply
* ignoring them.
*
* There is some ambiguity in the RFC, since there are other
* places that suggest that a target is supposed to be able to
* send an unsolicited NOP-In and expect a NOP-Out response.
* We catch any apparent attempts to use this immediately, so
* that the relevant error gets reported to the iPXE user,
* rather than just having the target drop the connection when
* it times out waiting for the NOP-Out response.
*/
if ( nop_in->itt != htonl ( ISCSI_TAG_RESERVED ) ) {
DBGC ( iscsi, "iSCSI %p received invalid NOP-In with ITT "
"%08x\n", iscsi, ntohl ( nop_in->itt ) );
return -EPROTO_INVALID_NOP_IN;
}
return 0;
}
/****************************************************************************
*
* iSCSI login
@ -1539,6 +1587,8 @@ static int iscsi_rx_data ( struct iscsi_session *iscsi, const void *data,
return iscsi_rx_data_in ( iscsi, data, len, remaining );
case ISCSI_OPCODE_R2T:
return iscsi_rx_r2t ( iscsi, data, len, remaining );
case ISCSI_OPCODE_NOP_IN:
return iscsi_rx_nop_in ( iscsi, data, len, remaining );
default:
if ( remaining )
return 0;