CIFS: Move RFC1002 check to a separate function

Reviewed-and-Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 67 insertions, 49 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a2e9fcf4a996..2a53ade3e637 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -416,6 +416,63 @@ read_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg,
         return rc;
 }
 
+static bool
+check_rfc1002_header(struct TCP_Server_Info *server, char *buf)
+{
+        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) {
+                /*
+                 * 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);
+                /* give server a second to clean up */
+                msleep(1000);
+                /*
+                 * Always try 445 first on reconnect since we get NACK
+                 * on some if we ever connected to port 139 (the NACK
+                 * is since we do not begin with RFC1001 session
+                 * initialize frame).
+                 */
+                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);
+                cifs_reconnect(server);
+                wake_up(&server->response_q);
+                return false;
+        }
+
+        return true;
+}
+
 static int
 cifs_demultiplex_thread(void *p)
 {
@@ -429,7 +486,6 @@ cifs_demultiplex_thread(void *p)
         struct list_head *tmp, *tmp2;
         struct task_struct *task_to_wake = NULL;
         struct mid_q_entry *mid_entry;
-        char temp;
         bool isLargeBuf = false;
         bool isMultiRsp;
         int rc;
@@ -482,59 +538,21 @@ incomplete_rcv:
                 else if (rc == 1)
                         continue;
 
-                /* The right amount was read from socket - 4 bytes */
-                /* so we can now interpret the length field */
-
-                /* 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 */
-                temp = *buf;
+                /*
+                 * The right amount was read from socket - 4 bytes,
+                 * so we can now interpret the length field.
+                 */
 
-                /* Note that FC 1001 length is big endian on the wire,
-                but we convert it here so it is always manipulated
-                as host byte order */
+                /*
+                 * Note that RFC 1001 length is big endian on the wire,
+                 * but we convert it here so it is always manipulated
+                 * as host byte order.
+                 */
                 pdu_length = be32_to_cpu(smb_buffer->smb_buf_length);
 
                 cFYI(1, "rfc1002 length 0x%x", pdu_length+4);
-
-                if (temp == (char) RFC1002_SESSION_KEEP_ALIVE) {
-                        continue;
-                } else if (temp == (char)RFC1002_POSITIVE_SESSION_RESPONSE) {
-                        cFYI(1, "Good RFC 1002 session rsp");
-                        continue;
-                } else if (temp == (char)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);
-                        /* give server a second to clean up  */
-                        msleep(1000);
-                        /* always try 445 first on reconnect since we get NACK
-                         * on some if we ever connected to port 139 (the NACK
-                         * is since we do not begin with RFC1001 session
-                         * initialize frame)
-                         */
-                        cifs_set_port((struct sockaddr *)
-                                        &server->dstaddr, CIFS_PORT);
-                        cifs_reconnect(server);
-                        wake_up(&server->response_q);
-                        continue;
-                } else if (temp != (char) 0) {
-                        cERROR(1, "Unknown RFC 1002 frame");
-                        cifs_dump_mem(" Received Data: ", buf, length);
-                        cifs_reconnect(server);
-                        continue;
-                }
-
-                /* 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",
-                                        length, pdu_length+4);
-                        cifs_reconnect(server);
-                        wake_up(&server->response_q);
+                if (!check_rfc1002_header(server, buf))
                         continue;
-                }
 
                 /* else length ok */
                 if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {