diff options
| author |   Tim Gardner <tim.gardner@canonical.com> | 2013-11-02 12:50:34 -0500 |
|---|---|---|
| committer |   Steve French <smfrench@gmail.com> | 2013-11-02 12:51:53 -0500 |
| commit | 3d378d3fd82a759d59c60d89b4559bf325d7e668 (patch) | |
| tree | 1fc4634672bc18c7af79f1029d42e99869beb2c4 /fs/cifs/smb1ops.c | |
| parent | cifs: Remove redundant multiplex identifier check from check_smb_hdr() (diff) | |
| download | linux-dev-3d378d3fd82a759d59c60d89b4559bf325d7e668.tar.xz linux-dev-3d378d3fd82a759d59c60d89b4559bf325d7e668.zip | |
cifs: Make big endian multiplex ID sequences monotonic on the wire
The multiplex identifier (MID) in the SMB header is only
ever used by the client, in conjunction with PID, to match responses
from the server. As such, the endianess of the MID is not important.
However, When tracing packet sequences on the wire, protocol analyzers
such as wireshark display MID as little endian. It is much more informative
for the on-the-wire MID sequences to match debug information emitted by the
CIFS driver. Therefore, one should write and read MID in the SMB header
assuming it is always little endian.
Observed from wireshark during the protocol negotiation
and session setup:
Multiplex ID: 256
Multiplex ID: 256
Multiplex ID: 512
Multiplex ID: 512
Multiplex ID: 768
Multiplex ID: 768
After this patch on-the-wire MID values begin at 1 and increase monotonically.
Introduce get_next_mid64() for the internal consumers that use the full 64 bit
multiplex identifier.
Introduce the helpers get_mid() and compare_mid() to make the endian
translation clear.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Tim Gardner <timg@tpi.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/smb1ops.c')
| -rw-r--r-- | fs/cifs/smb1ops.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c index 8233b174de3d..09ef8f322c2a 100644 --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -67,7 +67,7 @@ send_nt_cancel(struct TCP_Server_Info *server, void *buf, mutex_unlock(&server->srv_mutex); cifs_dbg(FYI, "issued NT_CANCEL for mid %u, rc = %d\n", - in_buf->Mid, rc); + get_mid(in_buf), rc); return rc; } @@ -101,7 +101,7 @@ cifs_find_mid(struct TCP_Server_Info *server, char *buffer) spin_lock(&GlobalMid_Lock); list_for_each_entry(mid, &server->pending_mid_q, qhead) { - if (mid->mid == buf->Mid && + if (compare_mid(mid->mid, buf) && mid->mid_state == MID_REQUEST_SUBMITTED && le16_to_cpu(mid->command) == buf->Command) { spin_unlock(&GlobalMid_Lock); |