CIFS: Separate SMB2 header structure

In order to support compounding and encryption we need to separate
RFC1001 length field and SMB2 header structure because the protocol
treats them differently. This change will allow to simplify parsing
of such complex SMB2 packets further.

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

1 files changed, 71 insertions, 61 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 87457227812c..0a668c756d56 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -83,6 +83,7 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 		  const struct cifs_tcon *tcon)
 {
 	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(hdr);
 	char *temp = (char *)hdr;
 	/* lookup word count ie StructureSize from table */
 	__u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_cmd)];
@@ -94,28 +95,28 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 	memset(temp, 0, 256);
 
 	/* Note this is only network field converted to big endian */
-	hdr->smb2_buf_length = cpu_to_be32(parmsize + sizeof(struct smb2_hdr)
-			- 4 /*  RFC 1001 length field itself not counted */);
+	hdr->smb2_buf_length =
+			cpu_to_be32(parmsize + sizeof(struct smb2_sync_hdr));
 
-	hdr->ProtocolId = SMB2_PROTO_NUMBER;
-	hdr->StructureSize = cpu_to_le16(64);
-	hdr->Command = smb2_cmd;
+	shdr->ProtocolId = SMB2_PROTO_NUMBER;
+	shdr->StructureSize = cpu_to_le16(64);
+	shdr->Command = smb2_cmd;
 	if (tcon && tcon->ses && tcon->ses->server) {
 		struct TCP_Server_Info *server = tcon->ses->server;
 
 		spin_lock(&server->req_lock);
 		/* Request up to 2 credits but don't go over the limit. */
 		if (server->credits >= server->max_credits)
-			hdr->CreditRequest = cpu_to_le16(0);
+			shdr->CreditRequest = cpu_to_le16(0);
 		else
-			hdr->CreditRequest = cpu_to_le16(
+			shdr->CreditRequest = cpu_to_le16(
 				min_t(int, server->max_credits -
 						server->credits, 2));
 		spin_unlock(&server->req_lock);
 	} else {
-		hdr->CreditRequest = cpu_to_le16(2);
+		shdr->CreditRequest = cpu_to_le16(2);
 	}
-	hdr->ProcessId = cpu_to_le32((__u16)current->tgid);
+	shdr->ProcessId = cpu_to_le32((__u16)current->tgid);
 
 	if (!tcon)
 		goto out;
@@ -124,13 +125,13 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 	/* See sections 2.2.4 and 3.2.4.1.5 of MS-SMB2 */
 	if ((tcon->ses) && (tcon->ses->server) &&
 	    (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
-		hdr->CreditCharge = cpu_to_le16(1);
+		shdr->CreditCharge = cpu_to_le16(1);
 	/* else CreditCharge MBZ */
 
-	hdr->TreeId = tcon->tid;
+	shdr->TreeId = tcon->tid;
 	/* Uid is not converted */
 	if (tcon->ses)
-		hdr->SessionId = tcon->ses->Suid;
+		shdr->SessionId = tcon->ses->Suid;
 
 	/*
 	 * If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
@@ -143,10 +144,10 @@ smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
 	 * but it is safer to net set it for now.
 	 */
 /*	if (tcon->share_flags & SHI1005_FLAGS_DFS)
-		hdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */
+		shdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */
 
 	if (tcon->ses && tcon->ses->server && tcon->ses->server->sign)
-		hdr->Flags |= SMB2_FLAGS_SIGNED;
+		shdr->Flags |= SMB2_FLAGS_SIGNED;
 out:
 	pdu->StructureSize2 = cpu_to_le16(parmsize);
 	return;
@@ -416,7 +417,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	if (rc)
 		return rc;
 
-	req->hdr.SessionId = 0;
+	req->hdr.sync_hdr.SessionId = 0;
 
 	req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);
 
@@ -627,14 +628,15 @@ SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
 	if (rc)
 		return rc;
 
-	req->hdr.SessionId = 0; /* First session, not a reauthenticate */
+	/* First session, not a reauthenticate */
+	req->hdr.sync_hdr.SessionId = 0;
 
 	/* if reconnect, we need to send previous sess id, otherwise it is 0 */
 	req->PreviousSessionId = sess_data->previous_session;
 
 	req->Flags = 0; /* MBZ */
 	/* to enable echos and oplocks */
-	req->hdr.CreditRequest = cpu_to_le16(3);
+	req->hdr.sync_hdr.CreditRequest = cpu_to_le16(3);
 
 	/* only one of SMB2 signing flags may be set in SMB2 request */
 	if (server->sign)
@@ -781,7 +783,7 @@ SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
 		goto out_put_spnego_key;
 
 	rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
-	ses->Suid = rsp->hdr.SessionId;
+	ses->Suid = rsp->hdr.sync_hdr.SessionId;
 
 	ses->session_flags = le16_to_cpu(rsp->SessionFlags);
 	if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
@@ -859,7 +861,7 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
 
 	/* If true, rc here is expected and not an error */
 	if (sess_data->buf0_type != CIFS_NO_BUFFER &&
-		rsp->hdr.Status == STATUS_MORE_PROCESSING_REQUIRED)
+		rsp->hdr.sync_hdr.Status == STATUS_MORE_PROCESSING_REQUIRED)
 		rc = 0;
 
 	if (rc)
@@ -880,7 +882,7 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
 	cifs_dbg(FYI, "rawntlmssp session setup challenge phase\n");
 
 
-	ses->Suid = rsp->hdr.SessionId;
+	ses->Suid = rsp->hdr.sync_hdr.SessionId;
 	ses->session_flags = le16_to_cpu(rsp->SessionFlags);
 	if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
 		cifs_dbg(VFS, "SMB3 encryption not supported yet\n");
@@ -916,7 +918,7 @@ SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
 		goto out;
 
 	req = (struct smb2_sess_setup_req *) sess_data->iov[0].iov_base;
-	req->hdr.SessionId = ses->Suid;
+	req->hdr.sync_hdr.SessionId = ses->Suid;
 
 	rc = build_ntlmssp_auth_blob(&ntlmssp_blob, &blob_length, ses,
 					sess_data->nls_cp);
@@ -940,7 +942,7 @@ SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
 
 	rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
 
-	ses->Suid = rsp->hdr.SessionId;
+	ses->Suid = rsp->hdr.sync_hdr.SessionId;
 	ses->session_flags = le16_to_cpu(rsp->SessionFlags);
 	if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
 		cifs_dbg(VFS, "SMB3 encryption not supported yet\n");
@@ -1035,9 +1037,9 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 		return rc;
 
 	 /* since no tcon, smb2_init can not do this, so do here */
-	req->hdr.SessionId = ses->Suid;
+	req->hdr.sync_hdr.SessionId = ses->Suid;
 	if (server->sign)
-		req->hdr.Flags |= SMB2_FLAGS_SIGNED;
+		req->hdr.sync_hdr.Flags |= SMB2_FLAGS_SIGNED;
 
 	rc = SendReceiveNoRsp(xid, ses, (char *) &req->hdr, 0);
 	/*
@@ -1112,7 +1114,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 
 	if (tcon == NULL) {
 		/* since no tcon, smb2_init can not do this, so do here */
-		req->hdr.SessionId = ses->Suid;
+		req->hdr.sync_hdr.SessionId = ses->Suid;
 		/* if (ses->server->sec_mode & SECMODE_SIGN_REQUIRED)
 			req->hdr.Flags |= SMB2_FLAGS_SIGNED; */
 	}
@@ -1142,7 +1144,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	}
 
 	if (tcon == NULL) {
-		ses->ipc_tid = rsp->hdr.TreeId;
+		ses->ipc_tid = rsp->hdr.sync_hdr.TreeId;
 		goto tcon_exit;
 	}
 
@@ -1165,7 +1167,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	tcon->maximal_access = le32_to_cpu(rsp->MaximalAccess);
 	tcon->tidStatus = CifsGood;
 	tcon->need_reconnect = false;
-	tcon->tid = rsp->hdr.TreeId;
+	tcon->tid = rsp->hdr.sync_hdr.TreeId;
 	strlcpy(tcon->treeName, tree, sizeof(tcon->treeName));
 
 	if ((rsp->Capabilities & SMB2_SHARE_CAP_DFS) &&
@@ -1182,7 +1184,7 @@ tcon_exit:
 	return rc;
 
 tcon_error_exit:
-	if (rsp->hdr.Status == STATUS_BAD_NETWORK_NAME) {
+	if (rsp->hdr.sync_hdr.Status == STATUS_BAD_NETWORK_NAME) {
 		cifs_dbg(VFS, "BAD_NETWORK_NAME: %s\n", tree);
 		if (tcon)
 			tcon->bad_network_name = true;
@@ -1618,6 +1620,7 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 {
 	struct smb2_ioctl_req *req;
 	struct smb2_ioctl_rsp *rsp;
+	struct smb2_sync_hdr *shdr;
 	struct TCP_Server_Info *server;
 	struct cifs_ses *ses;
 	struct kvec iov[2];
@@ -1742,9 +1745,8 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 		goto ioctl_exit;
 	}
 
-	memcpy(*out_data,
-	       (char *)&rsp->hdr.ProtocolId + le32_to_cpu(rsp->OutputOffset),
-	       *plen);
+	shdr = get_sync_hdr(rsp);
+	memcpy(*out_data, (char *)shdr + le32_to_cpu(rsp->OutputOffset), *plen);
 ioctl_exit:
 	free_rsp_buf(resp_buftype, rsp);
 	return rc;
@@ -1963,11 +1965,11 @@ static void
 smb2_echo_callback(struct mid_q_entry *mid)
 {
 	struct TCP_Server_Info *server = mid->callback_data;
-	struct smb2_echo_rsp *smb2 = (struct smb2_echo_rsp *)mid->resp_buf;
+	struct smb2_echo_rsp *rsp = (struct smb2_echo_rsp *)mid->resp_buf;
 	unsigned int credits_received = 1;
 
 	if (mid->mid_state == MID_RESPONSE_RECEIVED)
-		credits_received = le16_to_cpu(smb2->hdr.CreditRequest);
+		credits_received = le16_to_cpu(rsp->hdr.sync_hdr.CreditRequest);
 
 	mutex_lock(&server->srv_mutex);
 	DeleteMidQEntry(mid);
@@ -2045,7 +2047,7 @@ SMB2_echo(struct TCP_Server_Info *server)
 	if (rc)
 		return rc;
 
-	req->hdr.CreditRequest = cpu_to_le16(1);
+	req->hdr.sync_hdr.CreditRequest = cpu_to_le16(1);
 
 	iov.iov_base = (char *)req;
 	/* 4 for rfc1002 length field */
@@ -2108,6 +2110,7 @@ smb2_new_read_req(struct kvec *iov, struct cifs_io_parms *io_parms,
 {
 	int rc = -EACCES;
 	struct smb2_read_req *req = NULL;
+	struct smb2_sync_hdr *shdr;
 
 	rc = small_smb2_init(SMB2_READ, io_parms->tcon, (void **) &req);
 	if (rc)
@@ -2115,7 +2118,8 @@ smb2_new_read_req(struct kvec *iov, struct cifs_io_parms *io_parms,
 	if (io_parms->tcon->ses->server == NULL)
 		return -ECONNABORTED;
 
-	req->hdr.ProcessId = cpu_to_le32(io_parms->pid);
+	shdr = get_sync_hdr(req);
+	shdr->ProcessId = cpu_to_le32(io_parms->pid);
 
 	req->PersistentFileId = io_parms->persistent_fid;
 	req->VolatileFileId = io_parms->volatile_fid;
@@ -2129,18 +2133,18 @@ smb2_new_read_req(struct kvec *iov, struct cifs_io_parms *io_parms,
 	if (request_type & CHAINED_REQUEST) {
 		if (!(request_type & END_OF_CHAIN)) {
 			/* 4 for rfc1002 length field */
-			req->hdr.NextCommand =
+			shdr->NextCommand =
 				cpu_to_le32(get_rfc1002_length(req) + 4);
 		} else /* END_OF_CHAIN */
-			req->hdr.NextCommand = 0;
+			shdr->NextCommand = 0;
 		if (request_type & RELATED_REQUEST) {
-			req->hdr.Flags |= SMB2_FLAGS_RELATED_OPERATIONS;
+			shdr->Flags |= SMB2_FLAGS_RELATED_OPERATIONS;
 			/*
 			 * Related requests use info from previous read request
 			 * in chain.
 			 */
-			req->hdr.SessionId = 0xFFFFFFFF;
-			req->hdr.TreeId = 0xFFFFFFFF;
+			shdr->SessionId = 0xFFFFFFFF;
+			shdr->TreeId = 0xFFFFFFFF;
 			req->PersistentFileId = 0xFFFFFFFF;
 			req->VolatileFileId = 0xFFFFFFFF;
 		}
@@ -2162,7 +2166,7 @@ smb2_readv_callback(struct mid_q_entry *mid)
 	struct cifs_readdata *rdata = mid->callback_data;
 	struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
 	struct TCP_Server_Info *server = tcon->ses->server;
-	struct smb2_hdr *buf = (struct smb2_hdr *)rdata->iov.iov_base;
+	struct smb2_sync_hdr *shdr = get_sync_hdr(rdata->iov.iov_base);
 	unsigned int credits_received = 1;
 	struct smb_rqst rqst = { .rq_iov = &rdata->iov,
 				 .rq_nvec = 1,
@@ -2177,7 +2181,7 @@ smb2_readv_callback(struct mid_q_entry *mid)
 
 	switch (mid->mid_state) {
 	case MID_RESPONSE_RECEIVED:
-		credits_received = le16_to_cpu(buf->CreditRequest);
+		credits_received = le16_to_cpu(shdr->CreditRequest);
 		/* result already set, check signature */
 		if (server->sign) {
 			int rc;
@@ -2221,7 +2225,8 @@ int
 smb2_async_readv(struct cifs_readdata *rdata)
 {
 	int rc, flags = 0;
-	struct smb2_hdr *buf;
+	char *buf;
+	struct smb2_sync_hdr *shdr;
 	struct cifs_io_parms io_parms;
 	struct smb_rqst rqst = { .rq_iov = &rdata->iov,
 				 .rq_nvec = 1 };
@@ -2252,17 +2257,18 @@ smb2_async_readv(struct cifs_readdata *rdata)
 		return rc;
 	}
 
-	buf = (struct smb2_hdr *)rdata->iov.iov_base;
+	buf = rdata->iov.iov_base;
+	shdr = get_sync_hdr(buf);
 	/* 4 for rfc1002 length field */
 	rdata->iov.iov_len = get_rfc1002_length(rdata->iov.iov_base) + 4;
 
 	if (rdata->credits) {
-		buf->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
+		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
 						SMB2_MAX_BUFFER_SIZE));
-		buf->CreditRequest = buf->CreditCharge;
+		shdr->CreditRequest = shdr->CreditCharge;
 		spin_lock(&server->req_lock);
 		server->credits += rdata->credits -
-						le16_to_cpu(buf->CreditCharge);
+						le16_to_cpu(shdr->CreditCharge);
 		spin_unlock(&server->req_lock);
 		wake_up(&server->request_q);
 		flags = CIFS_HAS_CREDITS;
@@ -2287,6 +2293,7 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 {
 	int resp_buftype, rc = -EACCES;
 	struct smb2_read_rsp *rsp = NULL;
+	struct smb2_sync_hdr *shdr;
 	struct kvec iov[1];
 
 	*nbytes = 0;
@@ -2298,8 +2305,9 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 			  &resp_buftype, CIFS_LOG_ERROR);
 
 	rsp = (struct smb2_read_rsp *)iov[0].iov_base;
+	shdr = get_sync_hdr(rsp);
 
-	if (rsp->hdr.Status == STATUS_END_OF_FILE) {
+	if (shdr->Status == STATUS_END_OF_FILE) {
 		free_rsp_buf(resp_buftype, iov[0].iov_base);
 		return 0;
 	}
@@ -2319,8 +2327,7 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 	}
 
 	if (*buf) {
-		memcpy(*buf, (char *)&rsp->hdr.ProtocolId + rsp->DataOffset,
-		       *nbytes);
+		memcpy(*buf, (char *)shdr + rsp->DataOffset, *nbytes);
 		free_rsp_buf(resp_buftype, iov[0].iov_base);
 	} else if (resp_buftype != CIFS_NO_BUFFER) {
 		*buf = iov[0].iov_base;
@@ -2348,7 +2355,7 @@ smb2_writev_callback(struct mid_q_entry *mid)
 
 	switch (mid->mid_state) {
 	case MID_RESPONSE_RECEIVED:
-		credits_received = le16_to_cpu(rsp->hdr.CreditRequest);
+		credits_received = le16_to_cpu(rsp->hdr.sync_hdr.CreditRequest);
 		wdata->result = smb2_check_receive(mid, tcon->ses->server, 0);
 		if (wdata->result != 0)
 			break;
@@ -2394,6 +2401,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
 {
 	int rc = -EACCES, flags = 0;
 	struct smb2_write_req *req = NULL;
+	struct smb2_sync_hdr *shdr;
 	struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct kvec iov;
@@ -2412,7 +2420,8 @@ smb2_async_writev(struct cifs_writedata *wdata,
 		goto async_writev_out;
 	}
 
-	req->hdr.ProcessId = cpu_to_le32(wdata->cfile->pid);
+	shdr = get_sync_hdr(req);
+	shdr->ProcessId = cpu_to_le32(wdata->cfile->pid);
 
 	req->PersistentFileId = wdata->cfile->fid.persistent_fid;
 	req->VolatileFileId = wdata->cfile->fid.volatile_fid;
@@ -2444,12 +2453,12 @@ smb2_async_writev(struct cifs_writedata *wdata,
 	inc_rfc1001_len(&req->hdr, wdata->bytes - 1 /* Buffer */);
 
 	if (wdata->credits) {
-		req->hdr.CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
+		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
 						    SMB2_MAX_BUFFER_SIZE));
-		req->hdr.CreditRequest = req->hdr.CreditCharge;
+		shdr->CreditRequest = shdr->CreditCharge;
 		spin_lock(&server->req_lock);
 		server->credits += wdata->credits -
-					le16_to_cpu(req->hdr.CreditCharge);
+						le16_to_cpu(shdr->CreditCharge);
 		spin_unlock(&server->req_lock);
 		wake_up(&server->request_q);
 		flags = CIFS_HAS_CREDITS;
@@ -2495,7 +2504,7 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
 	if (io_parms->tcon->ses->server == NULL)
 		return -ECONNABORTED;
 
-	req->hdr.ProcessId = cpu_to_le32(io_parms->pid);
+	req->hdr.sync_hdr.ProcessId = cpu_to_le32(io_parms->pid);
 
 	req->PersistentFileId = io_parms->persistent_fid;
 	req->VolatileFileId = io_parms->volatile_fid;
@@ -2649,7 +2658,8 @@ SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 	rsp = (struct smb2_query_directory_rsp *)iov[0].iov_base;
 
 	if (rc) {
-		if (rc == -ENODATA && rsp->hdr.Status == STATUS_NO_MORE_FILES) {
+		if (rc == -ENODATA &&
+		    rsp->hdr.sync_hdr.Status == STATUS_NO_MORE_FILES) {
 			srch_inf->endOfSearch = true;
 			rc = 0;
 		}
@@ -2729,7 +2739,7 @@ send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
 		return rc;
 	}
 
-	req->hdr.ProcessId = cpu_to_le32(pid);
+	req->hdr.sync_hdr.ProcessId = cpu_to_le32(pid);
 
 	req->InfoType = SMB2_O_INFO_FILE;
 	req->FileInfoClass = info_class;
@@ -2895,7 +2905,7 @@ SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
 	req->VolatileFid = volatile_fid;
 	req->PersistentFid = persistent_fid;
 	req->OplockLevel = oplock_level;
-	req->hdr.CreditRequest = cpu_to_le16(1);
+	req->hdr.sync_hdr.CreditRequest = cpu_to_le16(1);
 
 	rc = SendReceiveNoRsp(xid, tcon->ses, (char *) req, CIFS_OBREAK_OP);
 	/* SMB2 buffer freed by function above */
@@ -3069,7 +3079,7 @@ smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon,
 	if (rc)
 		return rc;
 
-	req->hdr.ProcessId = cpu_to_le32(pid);
+	req->hdr.sync_hdr.ProcessId = cpu_to_le32(pid);
 	req->LockCount = cpu_to_le16(num_lock);
 
 	req->PersistentFileId = persist_fid;
@@ -3124,7 +3134,7 @@ SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon,
 	if (rc)
 		return rc;
 
-	req->hdr.CreditRequest = cpu_to_le16(1);
+	req->hdr.sync_hdr.CreditRequest = cpu_to_le16(1);
 	req->StructureSize = cpu_to_le16(36);
 	inc_rfc1001_len(req, 12);