incubator-nuttx/include/nuttx/net/slip.h

108 lines
3.9 KiB
C

/****************************************************************************
* include/nuttx/net/slip.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#ifndef __INCLUDE_NUTTX_NET_SLIP_H
#define __INCLUDE_NUTTX_NET_SLIP_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#ifdef CONFIG_NET_SLIP
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
/* SLIP Configuration:
*
* CONFIG_NET_SLIP - Enables building of the SLIP driver
* CONFIG_NET_SLIP_STACKSIZE - Provides the stack size for SLIP RX and TX
* threads. Default: 2048
* CONFIG_NET_SLIP_DEFPRIO - Provides the priority for SLIP RX and TX
* threads. Default 128.
* CONFIG_NET_NET_SLIP_PKTSIZE - Provides the size of the SLIP packet
* buffers. Default 296
*
* The Linux slip module hard-codes its MTU size to 296 (40 bytes for the
* IP+TCP headers plus 256 bytes of data). So you might as well set
* CONFIG_NET_SLIP_PKTSIZE to 296 as well.
*
* There may be an issue with this setting, however. I see that Linux
* uses a MTU of 296 and window of 256, but actually only sends 168 bytes
* of data: 40 + 128. I believe that is to allow for the 2x worst cast
* packet expansion. Ideally we would like to advertise the 256 MSS,
* but restrict transfers to 128 bytes (possibly by modifying the
* tcp_mss() macro).
*
* CONFIG_NET_SLIP_NINTERFACES determines the number of physical interfaces
* that will be supported.
*/
/****************************************************************************
* Public Data
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: slip_initialize
*
* Description:
* Instantiate a SLIP network interface.
*
* Input Parameters:
* intf - In the case where there are multiple SLIP interfaces, this
* value identifies which is to be initialized. The number of
* possible SLIP interfaces is determined by
* devname - This is the path to the serial device that will support SLIP.
* For example, this might be "/dev/ttyS1"
*
* Returned Value:
* OK on success; Negated errno on failure.
*
* Assumptions:
*
****************************************************************************/
int slip_initialize(int intf, FAR const char *devname);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_NET_SLIP */
#endif /* __INCLUDE_NUTTX_NET_SLIP_H */