1 files changed, 864 insertions, 0 deletions

diff --git a/fs/smb/server/connection.c b/fs/smb/server/connection.c
new file mode 100644
index 000000000..4cb92d659
--- /dev/null
+++ b/fs/smb/server/connection.c
@@ -0,0 +1,864 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) 2016 Namjae Jeon <namjae.jeon@protocolfreedom.org>
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/mutex.h>
+#include <linux/freezer.h>
+#include <linux/module.h>
+
+#include "server.h"
+#include "smb_common.h"
+#include "mgmt/ksmbd_ida.h"
+#include "mgmt/user_session.h"
+#include "connection.h"
+#include "vfs_cache.h"
+#include "compress.h"
+#include "transport_tcp.h"
+#include "transport_rdma.h"
+#include "misc.h"
+
+static DEFINE_MUTEX(init_lock);
+
+static struct ksmbd_conn_ops default_conn_ops;
+
+DEFINE_HASHTABLE(conn_list, CONN_HASH_BITS);
+DECLARE_RWSEM(conn_list_lock);
+
+#ifdef CONFIG_PROC_FS
+static struct proc_dir_entry *proc_clients;
+
+static const char *ksmbd_conn_state_string(struct ksmbd_conn *conn)
+{
+	switch (READ_ONCE(conn->status)) {
+	case KSMBD_SESS_NEW:
+		return "new";
+	case KSMBD_SESS_GOOD:
+		return "good";
+	case KSMBD_SESS_EXITING:
+		return "exiting";
+	case KSMBD_SESS_NEED_RECONNECT:
+		return "reconnect";
+	case KSMBD_SESS_NEED_NEGOTIATE:
+		return "negotiate";
+	case KSMBD_SESS_NEED_SETUP:
+		return "setup";
+	case KSMBD_SESS_RELEASING:
+		return "releasing";
+	default:
+		return "unknown";
+	}
+}
+
+static const char *ksmbd_conn_transport_string(struct ksmbd_conn *conn)
+{
+	if (conn->transport->ops->rdma_read || conn->transport->ops->rdma_write)
+		return "smbdirect";
+	return "tcp";
+}
+
+static void proc_show_conn_feature(struct seq_file *m, bool *separator,
+				   bool enabled, const char *name)
+{
+	if (!enabled)
+		return;
+	seq_printf(m, "%s%s", *separator ? "," : "", name);
+	*separator = true;
+}
+
+static void proc_show_conn_features(struct seq_file *m,
+				    struct ksmbd_conn *conn)
+{
+	bool separator = false;
+
+	proc_show_conn_feature(m, &separator,
+			       conn->sign || conn->signing_negotiated, "sign");
+	proc_show_conn_feature(m, &separator, conn->cipher_type, "encrypt");
+	proc_show_conn_feature(m, &separator,
+			       conn->compress_algorithm != SMB3_COMPRESS_NONE,
+			       "compress");
+	proc_show_conn_feature(m, &separator, conn->rdma_transform_ids,
+			       "rdma-transform");
+	proc_show_conn_feature(m, &separator, conn->posix_ext_supported, "posix");
+	if (!separator)
+		seq_puts(m, "none");
+}
+
+static int proc_show_clients(struct seq_file *m, void *v)
+{
+	struct ksmbd_conn *conn;
+	struct timespec64 now, t;
+	int i;
+
+	down_read(&conn_list_lock);
+	hash_for_each(conn_list, i, conn, hlist) {
+		unsigned int outstanding_credits, total_credits;
+		unsigned long id;
+		void *entry;
+		unsigned int sessions = 0;
+
+		jiffies_to_timespec64(jiffies - conn->last_active, &t);
+		ktime_get_real_ts64(&now);
+		t = timespec64_sub(now, t);
+
+		spin_lock(&conn->credits_lock);
+		outstanding_credits = conn->outstanding_credits;
+		total_credits = conn->total_credits;
+		spin_unlock(&conn->credits_lock);
+
+		rcu_read_lock();
+		xa_for_each(&conn->sessions, id, entry)
+			sessions++;
+		rcu_read_unlock();
+#if IS_ENABLED(CONFIG_IPV6)
+		if (!conn->inet_addr)
+			seq_printf(m, "client:\t%pI6c\n", &conn->inet6_addr);
+		else
+#endif
+			seq_printf(m, "client:\t%pI4\n", &conn->inet_addr);
+		seq_printf(m, "transport:\t%s\n", ksmbd_conn_transport_string(conn));
+		seq_printf(m, "state:\t%s\n", ksmbd_conn_state_string(conn));
+		seq_printf(m, "dialect:\t0x%04x\n", conn->dialect);
+		seq_printf(m, "credits:\t%u/%u\n", outstanding_credits,
+			   total_credits);
+		seq_printf(m, "sessions:\t%u\n", sessions);
+		seq_printf(m, "open_files:\t%d\n",
+			   atomic_read(&conn->stats.open_files_count));
+		seq_printf(m, "requests:\t%lld\n",
+			   atomic64_read(&conn->stats.request_served));
+		seq_puts(m, "features:\t");
+		proc_show_conn_features(m, conn);
+		seq_printf(m, "\nlast_active:\t%ptT\n\n", &t);
+	}
+	up_read(&conn_list_lock);
+	return 0;
+}
+
+static int create_proc_clients(void)
+{
+	proc_clients = ksmbd_proc_create("clients",
+					 proc_show_clients, NULL);
+	if (!proc_clients)
+		return -ENOMEM;
+	return 0;
+}
+
+static void delete_proc_clients(void)
+{
+	if (proc_clients) {
+		proc_remove(proc_clients);
+		proc_clients = NULL;
+	}
+}
+#else
+static int create_proc_clients(void) { return 0; }
+static void delete_proc_clients(void) {}
+#endif
+
+static struct workqueue_struct *ksmbd_conn_wq;
+
+int ksmbd_conn_wq_init(void)
+{
+	ksmbd_conn_wq = alloc_workqueue("ksmbd-conn-release",
+					WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
+	if (!ksmbd_conn_wq)
+		return -ENOMEM;
+	return 0;
+}
+
+void ksmbd_conn_wq_destroy(void)
+{
+	if (ksmbd_conn_wq) {
+		destroy_workqueue(ksmbd_conn_wq);
+		ksmbd_conn_wq = NULL;
+	}
+}
+
+/*
+ * __ksmbd_conn_release_work() - perform the final, once-per-struct cleanup
+ * of a ksmbd_conn whose refcount has just dropped to zero.
+ *
+ * This is the common release path used by ksmbd_conn_put() for the embedded
+ * state that outlives the connection thread: async_ida and the attached
+ * transport (which owns the socket and iov for TCP).  Called from a workqueue
+ * so that sleep-allowed teardown (sock_release -> tcp_close ->
+ * lock_sock_nested) never runs from an RCU softirq callback (free_opinfo_rcu)
+ * or any other non-sleeping putter context.
+ */
+static void __ksmbd_conn_release_work(struct work_struct *work)
+{
+	struct ksmbd_conn *conn =
+		container_of(work, struct ksmbd_conn, release_work);
+
+	ida_destroy(&conn->async_ida);
+	conn->transport->ops->free_transport(conn->transport);
+	kfree_sensitive(conn);
+}
+
+/**
+ * ksmbd_conn_get() - take a reference on @conn and return it.
+ *
+ * @conn: connection instance to get a reference to
+ *
+ * Returns @conn unchanged so callers can write
+ * "fp->conn = ksmbd_conn_get(work->conn);" in one expression.  Returns NULL
+ * if @conn is NULL.
+ */
+struct ksmbd_conn *ksmbd_conn_get(struct ksmbd_conn *conn)
+{
+	if (!conn)
+		return NULL;
+
+	atomic_inc(&conn->refcnt);
+	return conn;
+}
+
+/**
+ * ksmbd_conn_put() - drop a reference and, if it was the last, queue the
+ * release onto ksmbd_conn_wq so it runs from process context.
+ *
+ * @conn: connection instance to put a reference to
+ *
+ * Callable from any context including RCU softirq callbacks and non-sleeping
+ * locks; the actual release is deferred to the workqueue.  ksmbd_conn_wq is
+ * created in ksmbd_server_init() before any conn can be allocated and is
+ * destroyed in ksmbd_server_exit() after rcu_barrier(), so it is always
+ * non-NULL while a conn reference is held.
+ */
+void ksmbd_conn_put(struct ksmbd_conn *conn)
+{
+	if (!conn)
+		return;
+
+	if (atomic_dec_and_test(&conn->refcnt))
+		queue_work(ksmbd_conn_wq, &conn->release_work);
+}
+
+/**
+ * ksmbd_conn_free() - free resources of the connection instance
+ *
+ * @conn:	connection instance to be cleaned up
+ *
+ * During the thread termination, the corresponding conn instance
+ * resources(sock/memory) are released and finally the conn object is freed.
+ */
+void ksmbd_conn_free(struct ksmbd_conn *conn)
+{
+	down_write(&conn_list_lock);
+	hash_del(&conn->hlist);
+	up_write(&conn_list_lock);
+
+	/*
+	 * request_buf / preauth_info / mechToken are only ever accessed by the
+	 * connection handler thread that owns @conn.  ksmbd_conn_free() is
+	 * called from the transport free_transport() path when that thread is
+	 * exiting, so it is safe to release them unconditionally even when
+	 * ksmbd_conn_put() below is not the final putter (oplock / ksmbd_file
+	 * holders only retain the conn pointer, not these per-thread buffers).
+	 */
+	xa_destroy(&conn->sessions);
+	kvfree(conn->request_buf);
+	kfree_sensitive(conn->preauth_info);
+	kfree(conn->mechToken);
+	ksmbd_preauth_session_destroy(conn);
+	ksmbd_conn_put(conn);
+}
+
+/**
+ * ksmbd_conn_alloc() - initialize a new connection instance
+ *
+ * Return:	ksmbd_conn struct on success, otherwise NULL
+ */
+struct ksmbd_conn *ksmbd_conn_alloc(void)
+{
+	struct ksmbd_conn *conn;
+
+	conn = kzalloc_obj(struct ksmbd_conn, KSMBD_DEFAULT_GFP);
+	if (!conn)
+		return NULL;
+
+	conn->need_neg = true;
+	ksmbd_conn_set_new(conn);
+	conn->local_nls = load_nls("utf8");
+	if (!conn->local_nls)
+		conn->local_nls = load_nls_default();
+	if (IS_ENABLED(CONFIG_UNICODE))
+		conn->um = utf8_load(UNICODE_AGE(12, 1, 0));
+	else
+		conn->um = ERR_PTR(-EOPNOTSUPP);
+	if (IS_ERR(conn->um))
+		conn->um = NULL;
+	INIT_WORK(&conn->release_work, __ksmbd_conn_release_work);
+	atomic_set(&conn->req_running, 0);
+	atomic_set(&conn->r_count, 0);
+	atomic_set(&conn->refcnt, 1);
+	conn->total_credits = 1;
+	conn->outstanding_credits = 0;
+
+	/*
+	 * The command sequence window starts as the set { 0 } when the
+	 * connection is established.
+	 */
+	conn->seq_low = 0;
+	conn->seq_high = 1;
+	__set_bit(0, conn->seq_bitmap);
+
+	init_waitqueue_head(&conn->req_running_q);
+	init_waitqueue_head(&conn->r_count_q);
+	INIT_LIST_HEAD(&conn->requests);
+	INIT_LIST_HEAD(&conn->async_requests);
+	INIT_LIST_HEAD(&conn->preauth_sess_table);
+	spin_lock_init(&conn->request_lock);
+	spin_lock_init(&conn->credits_lock);
+	ida_init(&conn->async_ida);
+	xa_init(&conn->sessions);
+
+	spin_lock_init(&conn->llist_lock);
+	INIT_LIST_HEAD(&conn->lock_list);
+
+	init_rwsem(&conn->session_lock);
+
+	return conn;
+}
+
+bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c)
+{
+	struct ksmbd_conn *t;
+	int bkt;
+	bool ret = false;
+
+	down_read(&conn_list_lock);
+	hash_for_each(conn_list, bkt, t, hlist) {
+		if (memcmp(t->ClientGUID, c->ClientGUID, SMB2_CLIENT_GUID_SIZE))
+			continue;
+
+		ret = true;
+		break;
+	}
+	up_read(&conn_list_lock);
+	return ret;
+}
+
+void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
+{
+	struct ksmbd_conn *conn = work->conn;
+	struct list_head *requests_queue = NULL;
+
+	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
+		requests_queue = &conn->requests;
+
+	atomic_inc(&conn->req_running);
+	if (requests_queue) {
+		spin_lock(&conn->request_lock);
+		list_add_tail(&work->request_entry, requests_queue);
+		spin_unlock(&conn->request_lock);
+	}
+}
+
+void ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
+{
+	struct ksmbd_conn *conn = work->conn;
+
+	atomic_dec(&conn->req_running);
+	if (waitqueue_active(&conn->req_running_q))
+		wake_up(&conn->req_running_q);
+
+	if (list_empty(&work->request_entry) &&
+	    list_empty(&work->async_request_entry))
+		return;
+
+	spin_lock(&conn->request_lock);
+	list_del_init(&work->request_entry);
+	spin_unlock(&conn->request_lock);
+	if (work->asynchronous)
+		release_async_work(work);
+
+	wake_up_all(&conn->req_running_q);
+}
+
+static void ksmbd_conn_cancel_async_requests(struct ksmbd_conn *conn)
+{
+	struct ksmbd_work *work, *tmp;
+
+	ksmbd_debug(CONN, "Cancel pending async requests on releasing connection\n");
+	spin_lock(&conn->request_lock);
+	list_for_each_entry_safe(work, tmp, &conn->async_requests,
+				 async_request_entry) {
+		if (cmpxchg(&work->state, KSMBD_WORK_ACTIVE,
+			    KSMBD_WORK_CANCELLED) != KSMBD_WORK_ACTIVE)
+			continue;
+
+		ksmbd_debug(CONN, "Cancel async request id %d\n",
+			    work->async_id);
+		if (work->cancel_fn)
+			work->cancel_fn(work->cancel_argv);
+	}
+	spin_unlock(&conn->request_lock);
+}
+
+void ksmbd_conn_lock(struct ksmbd_conn *conn)
+{
+	mutex_lock(&conn->srv_mutex);
+}
+
+void ksmbd_conn_unlock(struct ksmbd_conn *conn)
+{
+	mutex_unlock(&conn->srv_mutex);
+}
+
+static bool ksmbd_session_is_bound_to_conn(struct ksmbd_session *sess,
+					   struct ksmbd_conn *conn)
+{
+	bool found;
+
+	rcu_read_lock();
+	found = xa_load(&conn->sessions, sess->id) == sess;
+	rcu_read_unlock();
+	if (found)
+		return true;
+
+	down_read(&sess->chann_lock);
+	found = xa_load(&sess->ksmbd_chann_list, (long)conn);
+	up_read(&sess->chann_lock);
+	return found;
+}
+
+void ksmbd_all_conn_set_status(struct ksmbd_session *sess, u32 status)
+{
+	struct ksmbd_conn *conn;
+	int bkt;
+
+	down_read(&conn_list_lock);
+	hash_for_each(conn_list, bkt, conn, hlist) {
+		if (ksmbd_session_is_bound_to_conn(sess, conn)) {
+			spin_lock(&conn->request_lock);
+			if (!ksmbd_conn_exiting(conn) &&
+			    !ksmbd_conn_releasing(conn))
+				WRITE_ONCE(conn->status, status);
+			spin_unlock(&conn->request_lock);
+		}
+	}
+	up_read(&conn_list_lock);
+}
+
+void ksmbd_conn_abort(struct ksmbd_conn *conn)
+{
+	bool shutdown = false;
+
+	spin_lock(&conn->request_lock);
+	if (!ksmbd_conn_exiting(conn) && !ksmbd_conn_releasing(conn)) {
+		ksmbd_conn_set_exiting(conn);
+		shutdown = true;
+	}
+	spin_unlock(&conn->request_lock);
+	wake_up_all(&conn->req_running_q);
+
+	if (shutdown && conn->transport->ops->shutdown)
+		conn->transport->ops->shutdown(conn->transport);
+}
+
+void ksmbd_conn_wait_idle(struct ksmbd_conn *conn)
+{
+	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
+}
+
+int ksmbd_conn_wait_idle_sess(struct ksmbd_conn *curr_conn,
+			      struct ksmbd_session *sess)
+{
+	struct ksmbd_conn *conn;
+	int rc, retry_count = 0, max_timeout = 120;
+	int rcount, bkt;
+
+retry_idle:
+	if (retry_count >= max_timeout)
+		return -EIO;
+
+	/* A blocked byte-range lock cannot drain until teardown wakes it. */
+	ksmbd_wake_session_blocked_works(sess);
+
+	down_read(&conn_list_lock);
+	hash_for_each(conn_list, bkt, conn, hlist) {
+		if (ksmbd_session_is_bound_to_conn(sess, conn)) {
+			rcount = (conn == curr_conn) ? 2 : 1;
+			if (atomic_read(&conn->req_running) >= rcount) {
+				rc = wait_event_timeout(conn->req_running_q,
+					atomic_read(&conn->req_running) < rcount,
+					HZ);
+				if (!rc) {
+					up_read(&conn_list_lock);
+					retry_count++;
+					goto retry_idle;
+				}
+			}
+		}
+	}
+	up_read(&conn_list_lock);
+
+	return 0;
+}
+
+static int __ksmbd_conn_write(struct ksmbd_work *work,
+			      struct ksmbd_transport_write *tx)
+{
+	struct ksmbd_conn *conn = work->conn;
+	int sent;
+
+	if (!work->response_buf) {
+		pr_err("NULL response header\n");
+		return -EINVAL;
+	}
+
+	if (work->send_no_response)
+		return 0;
+
+	if (!work->iov_idx)
+		return -EINVAL;
+
+	tx->iov = work->iov;
+	tx->iov_cnt = work->iov_cnt;
+	tx->size = get_rfc1002_len(work->iov[0].iov_base) + 4;
+	tx->need_invalidate_rkey = work->need_invalidate_rkey;
+	tx->remote_key = work->remote_key;
+
+	ksmbd_conn_lock(conn);
+	sent = conn->transport->ops->writev(conn->transport, tx);
+	ksmbd_conn_unlock(conn);
+
+	if (sent < 0) {
+		pr_err("Failed to send message: %d\n", sent);
+		return sent;
+	}
+
+	return 0;
+}
+
+int ksmbd_conn_write(struct ksmbd_work *work)
+{
+	struct ksmbd_transport_write tx = {};
+
+	return __ksmbd_conn_write(work, &tx);
+}
+
+int ksmbd_conn_write_eor(struct ksmbd_work *work)
+{
+	struct ksmbd_transport_write tx = {
+		.msg_flags = MSG_EOR,
+	};
+
+	return __ksmbd_conn_write(work, &tx);
+}
+
+int ksmbd_conn_rdma_read(struct ksmbd_conn *conn,
+			 void *buf, unsigned int buflen,
+			 struct smbdirect_buffer_descriptor_v1 *desc,
+			 unsigned int desc_len)
+{
+	int ret = -EINVAL;
+
+	if (conn->transport->ops->rdma_read)
+		ret = conn->transport->ops->rdma_read(conn->transport,
+						      buf, buflen,
+						      desc, desc_len);
+	return ret;
+}
+
+int ksmbd_conn_rdma_write(struct ksmbd_conn *conn,
+			  void *buf, unsigned int buflen,
+			  struct smbdirect_buffer_descriptor_v1 *desc,
+			  unsigned int desc_len)
+{
+	int ret = -EINVAL;
+
+	if (conn->transport->ops->rdma_write)
+		ret = conn->transport->ops->rdma_write(conn->transport,
+						       buf, buflen,
+						       desc, desc_len);
+	return ret;
+}
+
+bool ksmbd_conn_alive(struct ksmbd_conn *conn)
+{
+	if (!ksmbd_server_running())
+		return false;
+
+	if (ksmbd_conn_exiting(conn))
+		return false;
+
+	if (kthread_should_stop())
+		return false;
+
+	if (atomic_read(&conn->stats.open_files_count) > 0)
+		return true;
+
+	/*
+	 * Stop current session if the time that get last request from client
+	 * is bigger than deadtime user configured and opening file count is
+	 * zero.
+	 */
+	if (server_conf.deadtime > 0 &&
+	    time_after(jiffies, conn->last_active + server_conf.deadtime)) {
+		ksmbd_debug(CONN, "No response from client in %lu minutes\n",
+			    server_conf.deadtime / SMB_ECHO_INTERVAL);
+		return false;
+	}
+	return true;
+}
+
+/* "+2" for BCC field (ByteCount, 2 bytes) */
+#define SMB1_MIN_SUPPORTED_PDU_SIZE (sizeof(struct smb_hdr) + 2)
+#define SMB2_MIN_SUPPORTED_PDU_SIZE (sizeof(struct smb2_pdu))
+#define SMB2_TRANSFORM_MIN_SUPPORTED_PDU_SIZE	\
+	(sizeof(struct smb2_transform_hdr) + sizeof(struct smb2_hdr))
+
+/**
+ * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
+ * @p:		connection instance
+ *
+ * One thread each per connection
+ *
+ * Return:	0 on success
+ */
+int ksmbd_conn_handler_loop(void *p)
+{
+	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
+	struct ksmbd_transport *t = conn->transport;
+	unsigned int pdu_size, max_allowed_pdu_size, max_req;
+	__le32 proto;
+	char hdr_buf[4] = {0,};
+	int size;
+
+	mutex_init(&conn->srv_mutex);
+	__module_get(THIS_MODULE);
+
+	max_req = server_conf.max_inflight_req;
+	conn->last_active = jiffies;
+	set_freezable();
+	while (ksmbd_conn_alive(conn)) {
+		if (try_to_freeze())
+			continue;
+
+		kvfree(conn->request_buf);
+		conn->request_buf = NULL;
+
+recheck:
+		if (atomic_read(&conn->req_running) + 1 > max_req) {
+			wait_event_interruptible(conn->req_running_q,
+				atomic_read(&conn->req_running) < max_req);
+			goto recheck;
+		}
+
+		size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
+		if (size != sizeof(hdr_buf))
+			break;
+
+		pdu_size = get_rfc1002_len(hdr_buf);
+		ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);
+
+		max_allowed_pdu_size = ksmbd_max_allowed_pdu_size(conn);
+
+		if (pdu_size > max_allowed_pdu_size) {
+			pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n",
+					pdu_size, max_allowed_pdu_size,
+					READ_ONCE(conn->status));
+			break;
+		}
+
+		/*
+		 * Check maximum pdu size(0x00FFFFFF).
+		 */
+		if (pdu_size > MAX_STREAM_PROT_LEN)
+			break;
+
+		if (pdu_size < SMB1_MIN_SUPPORTED_PDU_SIZE)
+			break;
+
+		/* 4 for rfc1002 length field */
+		/* 1 for implied bcc[0] */
+		size = pdu_size + 4 + 1;
+		conn->request_buf = kvmalloc(size, KSMBD_DEFAULT_GFP);
+		if (!conn->request_buf)
+			break;
+
+		memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));
+
+		/*
+		 * We already read 4 bytes to find out PDU size, now
+		 * read in PDU
+		 */
+		size = t->ops->read(t, conn->request_buf + 4, pdu_size, 2);
+		if (size < 0) {
+			pr_err("sock_read failed: %d\n", size);
+			break;
+		}
+
+		if (size != pdu_size) {
+			pr_err("PDU error. Read: %d, Expected: %d\n",
+			       size, pdu_size);
+			continue;
+		}
+
+		if (((struct smb2_hdr *)smb_get_msg(conn->request_buf))->ProtocolId ==
+		    SMB2_COMPRESSION_TRANSFORM_ID) {
+			/*
+			 * Convert the transform into a normal RFC1002-framed SMB2
+			 * request before protocol validation and work allocation.
+			 */
+			if (ksmbd_decompress_request(conn))
+				break;
+			pdu_size = get_rfc1002_len(conn->request_buf);
+		}
+
+		if (!ksmbd_smb_request(conn))
+			break;
+
+		proto = *(__le32 *)smb_get_msg(conn->request_buf);
+		if (proto == SMB2_PROTO_NUMBER &&
+		    pdu_size < SMB2_MIN_SUPPORTED_PDU_SIZE)
+			break;
+
+		if (proto == SMB2_TRANSFORM_PROTO_NUM &&
+		    pdu_size < SMB2_TRANSFORM_MIN_SUPPORTED_PDU_SIZE)
+			break;
+
+		if (!default_conn_ops.process_fn) {
+			pr_err("No connection request callback\n");
+			break;
+		}
+
+		if (default_conn_ops.process_fn(conn)) {
+			pr_err("Cannot handle request\n");
+			break;
+		}
+	}
+
+	ksmbd_conn_set_releasing(conn);
+	ksmbd_conn_cancel_async_requests(conn);
+	/* Wait till all reference dropped to the Server object*/
+	ksmbd_debug(CONN, "Wait for all pending requests(%d)\n", atomic_read(&conn->r_count));
+	wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);
+
+	if (IS_ENABLED(CONFIG_UNICODE))
+		utf8_unload(conn->um);
+	unload_nls(conn->local_nls);
+	if (default_conn_ops.terminate_fn)
+		default_conn_ops.terminate_fn(conn);
+	t->ops->disconnect(t);
+	module_put(THIS_MODULE);
+	return 0;
+}
+
+void ksmbd_conn_init_server_callbacks(struct ksmbd_conn_ops *ops)
+{
+	default_conn_ops.process_fn = ops->process_fn;
+	default_conn_ops.terminate_fn = ops->terminate_fn;
+}
+
+void ksmbd_conn_r_count_inc(struct ksmbd_conn *conn)
+{
+	atomic_inc(&conn->r_count);
+}
+
+void ksmbd_conn_r_count_dec(struct ksmbd_conn *conn)
+{
+	/*
+	 * Checking waitqueue to dropping pending requests on
+	 * disconnection. waitqueue_active is safe because it
+	 * uses atomic operation for condition.
+	 */
+	atomic_inc(&conn->refcnt);
+	if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
+		wake_up(&conn->r_count_q);
+
+	ksmbd_conn_put(conn);
+}
+
+int ksmbd_conn_transport_init(void)
+{
+	int ret;
+
+	mutex_lock(&init_lock);
+	ret = ksmbd_tcp_init();
+	if (ret) {
+		pr_err("Failed to init TCP subsystem: %d\n", ret);
+		goto out;
+	}
+
+	ret = ksmbd_rdma_init();
+	if (ret) {
+		pr_err("Failed to init RDMA subsystem: %d\n", ret);
+		goto out;
+	}
+out:
+	mutex_unlock(&init_lock);
+	if (create_proc_clients())
+		pr_warn("Unable to create clients procfs entry\n");
+	return ret;
+}
+
+static void stop_sessions(void)
+{
+	struct ksmbd_conn *conn, *target;
+	struct ksmbd_transport *t;
+	bool any;
+	int bkt;
+
+	/*
+	 * Serialised via init_lock; no concurrent stop_sessions() can
+	 * touch conn->stop_called, so writing it under the read lock is
+	 * safe.
+	 */
+again:
+	target = NULL;
+	any = false;
+	down_read(&conn_list_lock);
+	hash_for_each(conn_list, bkt, conn, hlist) {
+		any = true;
+		if (conn->stop_called)
+			continue;
+		atomic_inc(&conn->refcnt);
+		conn->stop_called = true;
+		/*
+		 * Mark the connection EXITING while still holding the
+		 * read lock so the selection and the status transition
+		 * happen together.  Do not regress a connection that has
+		 * already advanced to RELEASING on its own (e.g. the
+		 * handler exited its receive loop for an unrelated
+		 * reason).
+		 */
+		spin_lock(&conn->request_lock);
+		if (!ksmbd_conn_releasing(conn))
+			ksmbd_conn_set_exiting(conn);
+		spin_unlock(&conn->request_lock);
+		target = conn;
+		break;
+	}
+	up_read(&conn_list_lock);
+
+	if (target) {
+		t = target->transport;
+		if (t->ops->shutdown)
+			t->ops->shutdown(t);
+		if (atomic_dec_and_test(&target->refcnt)) {
+			ida_destroy(&target->async_ida);
+			t->ops->free_transport(t);
+			kfree_sensitive(target);
+		}
+		goto again;
+	}
+
+	if (any) {
+		msleep(100);
+		goto again;
+	}
+}
+
+void ksmbd_conn_transport_destroy(void)
+{
+	delete_proc_clients();
+	mutex_lock(&init_lock);
+	ksmbd_tcp_destroy();
+	ksmbd_rdma_stop_listening();
+	stop_sessions();
+	mutex_unlock(&init_lock);
+}