CIFS: Add capability to transform requests before sending

This will allow us to do protocol specific tranformations of packets
before sending to the server. For SMB3 it can be used to support
encryption.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>

1 files changed, 25 insertions, 8 deletions

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 729e5b7b8044..3e5791aae0f6 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -221,7 +221,7 @@ rqst_len(struct smb_rqst *rqst)
 }
 
 static int
-smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
+__smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 {
 	int rc;
 	struct kvec *iov = rqst->rq_iov;
@@ -313,12 +313,27 @@ uncork:
 }
 
 static int
-smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
+smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst, int flags)
 {
-	struct smb_rqst rqst = { .rq_iov = iov,
-				 .rq_nvec = n_vec };
+	struct smb_rqst cur_rqst;
+	int rc;
+
+	if (!(flags & CIFS_TRANSFORM_REQ))
+		return __smb_send_rqst(server, rqst);
+
+	if (!server->ops->init_transform_rq ||
+	    !server->ops->free_transform_rq) {
+		cifs_dbg(VFS, "Encryption requested but transform callbacks are missed\n");
+		return -EIO;
+	}
 
-	return smb_send_rqst(server, &rqst);
+	rc = server->ops->init_transform_rq(server, &cur_rqst, rqst);
+	if (rc)
+		return rc;
+
+	rc = __smb_send_rqst(server, &cur_rqst);
+	server->ops->free_transform_rq(&cur_rqst);
+	return rc;
 }
 
 int
@@ -326,13 +341,15 @@ smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
 	 unsigned int smb_buf_length)
 {
 	struct kvec iov[2];
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = 2 };
 
 	iov[0].iov_base = smb_buffer;
 	iov[0].iov_len = 4;
 	iov[1].iov_base = (char *)smb_buffer + 4;
 	iov[1].iov_len = smb_buf_length;
 
-	return smb_sendv(server, iov, 2);
+	return __smb_send_rqst(server, &rqst);
 }
 
 static int
@@ -524,7 +541,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 
 
 	cifs_in_send_inc(server);
-	rc = smb_send_rqst(server, rqst);
+	rc = smb_send_rqst(server, rqst, flags);
 	cifs_in_send_dec(server);
 	cifs_save_when_sent(mid);
 
@@ -718,7 +735,7 @@ cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
 
 	midQ->mid_state = MID_REQUEST_SUBMITTED;
 	cifs_in_send_inc(ses->server);
-	rc = smb_send_rqst(ses->server, rqst);
+	rc = smb_send_rqst(ses->server, rqst, flags);
 	cifs_in_send_dec(ses->server);
 	cifs_save_when_sent(midQ);