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feat: read and validate unit serial number after login

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this patch adds a read of VPD page 0x80 (unit serial number) after successful login.

The serial is then validated on secutive reconnects to avoid the accidental mismatch
of LUN ids if some kind of remapping appears between loss of connection and a later
reconnect.

An additional url parameter force_usn is added to enforce the usn right from the beginning.
If not set via url or the new iscsi_set_unit_serial_number function the usn is learned
at the first successful login.

Signed-off-by: Peter Lieven <pl@dlhnet.de>
This commit is contained in:
Peter Lieven
2025-09-11 15:15:42 +00:00
parent 9b1a625adc
commit 8c4e2ad46b
5 changed files with 128 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
README.md
View File

@@ -48,10 +48,11 @@ target_password=<password>
header_digest=<crc32c|none>
data_digest=<crc32c|none>
auth=<md5|sha1|sha-256|sha3-256>
force_usn=<unit_serial_number>
Transport:
iser
Example:
iscsi://server/iqn.ronnie.test/1

1
include/iscsi-private.h
View File

@@ -116,6 +116,7 @@ struct iscsi_context {
char portal[MAX_STRING_SIZE+1];
char alias[MAX_STRING_SIZE+1];
char bind_interfaces[MAX_STRING_SIZE+1];
char unit_serial_number[MAX_STRING_SIZE+1];
enum iscsi_chap_auth chap_auth;
char user[MAX_STRING_SIZE+1];

18
include/iscsi.h
View File

@@ -301,6 +301,24 @@ EXTERN int iscsi_set_alias(struct iscsi_context *iscsi, const char *alias);
*/
EXTERN int iscsi_set_targetname(struct iscsi_context *iscsi, const char *targetname);
/*
* Set the unit serial number (usn) as reported by VPD page 0x80.
* If set the usn is validated after logging in and especially after reconnecting
* to a target to avoid accidently mismatch between LUN ids on the same target.
* If not set explicitely the usn is learned at the first successful login to the target.
*
* Returns:
* 0: success
* <0: error
*/
EXTERN int iscsi_set_unit_serial_number(struct iscsi_context *iscsi, const char *usn);
/*
* This function returns a pointer to the unit serial number that is valid if explicitely
* set or after the first successful login to the target.
*/
EXTERN const char *iscsi_get_unit_serial_number(struct iscsi_context *iscsi);
/*
* This function returns any target address supplied in a login response when
* the target has moved.

66
lib/connect.c
View File

@@ -76,6 +76,50 @@ iscsi_testunitready_connect(struct iscsi_context *iscsi, int lun,
return task;
}
static struct scsi_task *
iscsi_inquiry_page_0x80_connect(struct iscsi_context *iscsi, int lun,
iscsi_command_cb cb, void *private_data)
{
struct scsi_task *task;
struct iscsi_context *old_iscsi = iscsi->old_iscsi;
iscsi->old_iscsi = NULL;
task = iscsi_inquiry_task(iscsi, lun, 1, 0x80, MAX_STRING_SIZE + 64,
cb, private_data);
iscsi->old_iscsi = old_iscsi;
return task;
}
static void
iscsi_inquiry_page_0x80_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *private_data)
{
struct connect_task *ct = private_data;
struct scsi_task *task = command_data;
struct scsi_inquiry_unit_serial_number *inq;
if (!status) {
inq = scsi_datain_unmarshall(task);
if (!iscsi->unit_serial_number[0]) {
ISCSI_LOG(iscsi, 2, "unit serial number is [%s]", inq->usn);
strncpy(iscsi->unit_serial_number, inq->usn, MAX_STRING_SIZE);
} else if (strncmp(iscsi->unit_serial_number, inq->usn, MAX_STRING_SIZE)) {
iscsi_set_error(iscsi, "unit serial number mismatch. got [%s] expected [%s]",
inq->usn, iscsi->unit_serial_number);
status = 1;
} else {
ISCSI_LOG(iscsi, 2, "successfully validated unit serial number [%s]", inq->usn);
}
} else {
iscsi_set_error(iscsi, "iscsi_inquiry_task failed. could not read vpd page 0x80.");
}
ct->cb(iscsi, status?SCSI_STATUS_ERROR:SCSI_STATUS_GOOD, NULL, ct->private_data);
scsi_free_scsi_task(task);
iscsi_free(iscsi, ct);
}
static void
iscsi_testunitready_cb(struct iscsi_context *iscsi, int status,
void *command_data, void *private_data)
@@ -137,10 +181,21 @@ iscsi_testunitready_cb(struct iscsi_context *iscsi, int status,
status = 0;
}
ct->cb(iscsi, status?SCSI_STATUS_ERROR:SCSI_STATUS_GOOD, NULL,
if (status != 0) {
ct->cb(iscsi, SCSI_STATUS_ERROR, NULL,
ct->private_data);
scsi_free_scsi_task(task);
iscsi_free(iscsi, ct);
return;
}
if (iscsi_inquiry_page_0x80_connect(iscsi, ct->lun,
iscsi_inquiry_page_0x80_cb,
ct) == NULL) {
iscsi_set_error(iscsi, "iscsi_inquiry_task failed.");
ct->cb(iscsi, SCSI_STATUS_ERROR, NULL, ct->private_data);
iscsi_free(iscsi, ct);
}
}
static void
@@ -178,9 +233,14 @@ iscsi_login_cb(struct iscsi_context *iscsi, int status, void *command_data,
iscsi_free(iscsi, ct);
}
} else {
ct->cb(iscsi, SCSI_STATUS_GOOD, NULL, ct->private_data);
if (iscsi_inquiry_page_0x80_connect(iscsi, ct->lun,
iscsi_inquiry_page_0x80_cb,
ct) == NULL) {
iscsi_set_error(iscsi, "iscsi_inquiry_task failed.");
ct->cb(iscsi, SCSI_STATUS_ERROR, NULL, ct->private_data);
iscsi_free(iscsi, ct);
}
}
}
static void
@@ -447,6 +507,8 @@ static int reconnect(struct iscsi_context *iscsi, int force)
strncpy(tmp_iscsi->bind_interfaces, iscsi->bind_interfaces, MAX_STRING_SIZE);
tmp_iscsi->bind_interfaces_cnt = iscsi->bind_interfaces_cnt;
strncpy(tmp_iscsi->unit_serial_number, iscsi->unit_serial_number, MAX_STRING_SIZE);
tmp_iscsi->log_level = iscsi->log_level;
tmp_iscsi->log_fn = iscsi->log_fn;
tmp_iscsi->tcp_user_timeout = iscsi->tcp_user_timeout;

28
lib/init.c
View File

@@ -345,6 +345,26 @@ iscsi_set_targetname(struct iscsi_context *iscsi, const char *target_name)
return 0;
}
int
iscsi_set_unit_serial_number(struct iscsi_context *iscsi, const char *usn)
{
if (iscsi->is_loggedin != 0) {
iscsi_set_error(iscsi, "Already logged in when adding "
"unit_serial_number");
return -1;
}
strncpy(iscsi->unit_serial_number,usn,MAX_STRING_SIZE);
return 0;
}
const char *
iscsi_get_unit_serial_number(struct iscsi_context *iscsi)
{
return iscsi ? iscsi->unit_serial_number : "";
}
int
iscsi_destroy_context(struct iscsi_context *iscsi)
{
@@ -521,6 +541,7 @@ iscsi_parse_url(struct iscsi_context *iscsi, const char *url, int full)
char *passwd = NULL;
char *target_user = NULL;
char *target_passwd = NULL;
char *usn = NULL;
char *target = NULL;
char *lun;
char *tmp;
@@ -628,6 +649,9 @@ iscsi_parse_url(struct iscsi_context *iscsi, const char *url, int full)
iscsi->rdma_ack_timeout = atoi(value);
#endif
}
if (!strcmp(key, "force_usn")) {
usn = value;
}
tmp = next;
}
}
@@ -743,6 +767,9 @@ iscsi_parse_url(struct iscsi_context *iscsi, const char *url, int full)
iscsi_set_targetname(iscsi, iscsi_url->target);
iscsi_set_initiator_username_pwd(iscsi, iscsi_url->user, iscsi_url->passwd);
iscsi_set_target_username_pwd(iscsi, iscsi_url->target_user, iscsi_url->target_passwd);
if (usn) {
iscsi_set_unit_serial_number(iscsi, usn);
}
}
return iscsi_url;
@@ -854,4 +881,3 @@ iscsi_set_auth(struct iscsi_context *iscsi, enum iscsi_chap_auth auth)
{
iscsi->chap_auth = auth;
}