nvmet: implement unique discovery NQN
Unique discovery NQNs allow to differentiate between discovery
services from (typically physically separate) NVMe-oF subsystems.
This is required for establishing secured connections as otherwise
the credentials won't be unique and the integrity of the connection
cannot be guaranteed.
This patch adds a configfs attribute 'discovery_nqn' in the 'nvmet'
configfs directory to specify the unique discovery NQN.
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 77a6e81..a232533 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -1613,6 +1613,11 @@
return ERR_PTR(-EINVAL);
}
+ if (sysfs_streq(name, nvmet_disc_subsys->subsysnqn)) {
+ pr_err("can't create subsystem using unique discovery NQN\n");
+ return ERR_PTR(-EINVAL);
+ }
+
subsys = nvmet_subsys_alloc(name, NVME_NQN_NVME);
if (IS_ERR(subsys))
return ERR_CAST(subsys);
@@ -2159,7 +2164,49 @@
static struct config_group nvmet_hosts_group;
+static ssize_t nvmet_root_discovery_nqn_show(struct config_item *item,
+ char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%s\n", nvmet_disc_subsys->subsysnqn);
+}
+
+static ssize_t nvmet_root_discovery_nqn_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct list_head *entry;
+ size_t len;
+
+ len = strcspn(page, "\n");
+ if (!len || len > NVMF_NQN_FIELD_LEN - 1)
+ return -EINVAL;
+
+ down_write(&nvmet_config_sem);
+ list_for_each(entry, &nvmet_subsystems_group.cg_children) {
+ struct config_item *item =
+ container_of(entry, struct config_item, ci_entry);
+
+ if (!strncmp(config_item_name(item), page, len)) {
+ pr_err("duplicate NQN %s\n", config_item_name(item));
+ up_write(&nvmet_config_sem);
+ return -EINVAL;
+ }
+ }
+ memset(nvmet_disc_subsys->subsysnqn, 0, NVMF_NQN_FIELD_LEN);
+ memcpy(nvmet_disc_subsys->subsysnqn, page, len);
+ up_write(&nvmet_config_sem);
+
+ return len;
+}
+
+CONFIGFS_ATTR(nvmet_root_, discovery_nqn);
+
+static struct configfs_attribute *nvmet_root_attrs[] = {
+ &nvmet_root_attr_discovery_nqn,
+ NULL,
+};
+
static const struct config_item_type nvmet_root_type = {
+ .ct_attrs = nvmet_root_attrs,
.ct_owner = THIS_MODULE,
};
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 6bbe4df..8860a3e 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1541,6 +1541,13 @@
}
down_read(&nvmet_config_sem);
+ if (!strncmp(nvmet_disc_subsys->subsysnqn, subsysnqn,
+ NVMF_NQN_SIZE)) {
+ if (kref_get_unless_zero(&nvmet_disc_subsys->ref)) {
+ up_read(&nvmet_config_sem);
+ return nvmet_disc_subsys;
+ }
+ }
list_for_each_entry(p, &port->subsystems, entry) {
if (!strncmp(p->subsys->subsysnqn, subsysnqn,
NVMF_NQN_SIZE)) {