cifs: clean up check_rfc1002_header

Rename it for better clarity as to what it does and have the caller pass
in just the single type byte. Turn the if statement into a switch and
optimize it by placing the most common message type at the top. Move the
header length check back into cifs_demultiplex_thread in preparation
for adding a new receive phase and normalize the cFYI messages.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 30 insertions, 33 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 82bc0d27e495..97a65af2a08a 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -427,29 +427,29 @@ read_from_socket(struct TCP_Server_Info *server, char *buf,
 }
 
 static bool
-check_rfc1002_header(struct TCP_Server_Info *server, char *buf)
+is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 {
-        char temp = *buf;
-        unsigned int pdu_length = be32_to_cpu(
-                                ((struct smb_hdr *)buf)->smb_buf_length);
-
         /*
          * The first byte big endian of the length field,
          * is actually not part of the length but the type
          * with the most common, zero, as regular data.
          */
-        if (temp == (char) RFC1002_SESSION_KEEP_ALIVE) {
-                return false;
-        } else if (temp == (char)RFC1002_POSITIVE_SESSION_RESPONSE) {
-                cFYI(1, "Good RFC 1002 session rsp");
-                return false;
-        } else if (temp == (char)RFC1002_NEGATIVE_SESSION_RESPONSE) {
+        switch (type) {
+        case RFC1002_SESSION_MESSAGE:
+                /* Regular SMB response */
+                return true;
+        case RFC1002_SESSION_KEEP_ALIVE:
+                cFYI(1, "RFC 1002 session keep alive");
+                break;
+        case RFC1002_POSITIVE_SESSION_RESPONSE:
+                cFYI(1, "RFC 1002 positive session response");
+                break;
+        case RFC1002_NEGATIVE_SESSION_RESPONSE:
                 /*
                  * We get this from Windows 98 instead of an error on
                  * SMB negprot response.
                  */
-                cFYI(1, "Negative RFC1002 Session Response Error 0x%x)",
-                        pdu_length);
+                cFYI(1, "RFC 1002 negative session response");
                 /* give server a second to clean up */
                 msleep(1000);
                 /*
@@ -458,29 +458,16 @@ check_rfc1002_header(struct TCP_Server_Info *server, char *buf)
                  * is since we do not begin with RFC1001 session
                  * initialize frame).
                  */
-                cifs_set_port((struct sockaddr *)
-                                &server->dstaddr, CIFS_PORT);
+                cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
                 cifs_reconnect(server);
                 wake_up(&server->response_q);
-                return false;
-        } else if (temp != (char) 0) {
-                cERROR(1, "Unknown RFC 1002 frame");
-                cifs_dump_mem(" Received Data: ", buf, 4);
-                cifs_reconnect(server);
-                return false;
-        }
-
-        /* else we have an SMB response */
-        if ((pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) ||
-            (pdu_length < sizeof(struct smb_hdr) - 1 - 4)) {
-                cERROR(1, "Invalid size SMB length %d pdu_length %d",
-                       4, pdu_length+4);
+                break;
+        default:
+                cERROR(1, "RFC 1002 unknown response type 0x%x", type);
                 cifs_reconnect(server);
-                wake_up(&server->response_q);
-                return false;
         }
 
-        return true;
+        return false;
 }
 
 static struct mid_q_entry *
@@ -683,10 +670,20 @@ cifs_demultiplex_thread(void *p)
                  */
                 pdu_length = be32_to_cpu(smb_buffer->smb_buf_length);
 
-                cFYI(1, "rfc1002 length 0x%x", pdu_length+4);
-                if (!check_rfc1002_header(server, buf))
+                cFYI(1, "RFC1002 header 0x%x", pdu_length);
+                if (!is_smb_response(server, buf[0]))
                         continue;
 
+                /* check the length */
+                if ((pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) ||
+                    (pdu_length < sizeof(struct smb_hdr) - 1 - 4)) {
+                        cERROR(1, "Invalid size SMB length %d pdu_length %d",
+                               4, pdu_length + 4);
+                        cifs_reconnect(server);
+                        wake_up(&server->response_q);
+                        continue;
+                }
+
                 /* else length ok */
                 if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
                         isLargeBuf = true;