adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 1 | /** |
| 2 | * \addtogroup uip |
| 3 | * @{ |
| 4 | */ |
| 5 | |
| 6 | /** |
| 7 | * \defgroup slip Serial Line IP (SLIP) protocol |
| 8 | * @{ |
| 9 | * |
| 10 | * The SLIP protocol is a very simple way to transmit IP packets over |
| 11 | * a serial line. It does not provide any framing or error control, |
| 12 | * and is therefore not very widely used today. |
| 13 | * |
| 14 | * This SLIP implementation requires two functions for accessing the |
| 15 | * serial device: slipdev_char_poll() and slipdev_char_put(). These |
| 16 | * must be implemented specifically for the system on which the SLIP |
| 17 | * protocol is to be run. |
| 18 | */ |
| 19 | |
| 20 | /** |
| 21 | * \file |
| 22 | * SLIP protocol implementation |
| 23 | * \author Adam Dunkels <adam@dunkels.com> |
| 24 | */ |
| 25 | |
| 26 | /* |
| 27 | * Copyright (c) 2001, Adam Dunkels. |
| 28 | * All rights reserved. |
| 29 | * |
| 30 | * Redistribution and use in source and binary forms, with or without |
| 31 | * modification, are permitted provided that the following conditions |
| 32 | * are met: |
| 33 | * 1. Redistributions of source code must retain the above copyright |
| 34 | * notice, this list of conditions and the following disclaimer. |
| 35 | * 2. Redistributions in binary form must reproduce the above copyright |
| 36 | * notice, this list of conditions and the following disclaimer in the |
| 37 | * documentation and/or other materials provided with the distribution. |
| 38 | * 3. The name of the author may not be used to endorse or promote |
| 39 | * products derived from this software without specific prior |
| 40 | * written permission. |
| 41 | * |
| 42 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| 43 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 44 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 45 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| 46 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 47 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| 48 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 49 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 50 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 51 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 52 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 53 | * |
| 54 | * This file is part of the uIP TCP/IP stack. |
| 55 | * |
adamdunkels | d913334 | 2003-11-27 15:54:20 +0000 | [diff] [blame] | 56 | * $Id: slipdev.c,v 1.2 2003/11/27 15:54:20 adamdunkels Exp $ |
adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 57 | * |
| 58 | */ |
| 59 | |
| 60 | /* |
| 61 | * This is a generic implementation of the SLIP protocol over an RS232 |
| 62 | * (serial) device. |
| 63 | * |
| 64 | * Huge thanks to Ullrich von Bassewitz <uz@cc65.org> of cc65 fame for |
| 65 | * and endless supply of bugfixes, insightsful comments and |
| 66 | * suggestions, and improvements to this code! |
| 67 | */ |
| 68 | |
| 69 | #include "uip.h" |
adamdunkels | d913334 | 2003-11-27 15:54:20 +0000 | [diff] [blame] | 70 | #include "uip-fw.h" |
adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 71 | #include "slipdev.h" |
| 72 | #include <string.h> /* For memcpy() */ |
| 73 | |
| 74 | #define SLIP_END 0300 |
| 75 | #define SLIP_ESC 0333 |
| 76 | #define SLIP_ESC_END 0334 |
| 77 | #define SLIP_ESC_ESC 0335 |
| 78 | |
| 79 | static u8_t slip_buf[UIP_BUFSIZE]; |
| 80 | |
| 81 | static u16_t len, tmplen; |
| 82 | static u8_t lastc; |
| 83 | |
| 84 | /*-----------------------------------------------------------------------------------*/ |
| 85 | /** |
| 86 | * Send the packet in the uip_buf and uip_appdata buffers using the |
| 87 | * SLIP protocol. |
| 88 | * |
| 89 | * The first 40 bytes of the packet (the IP and TCP headers) are read |
| 90 | * from the uip_buf buffer, and the following bytes (the application |
| 91 | * data) are read from the uip_appdata buffer. |
| 92 | * |
adamdunkels | d913334 | 2003-11-27 15:54:20 +0000 | [diff] [blame] | 93 | * \return This function will always return UIP_FW_OK. |
adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 94 | */ |
| 95 | /*-----------------------------------------------------------------------------------*/ |
adamdunkels | d913334 | 2003-11-27 15:54:20 +0000 | [diff] [blame] | 96 | u8_t |
adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 97 | slipdev_send(void) |
| 98 | { |
| 99 | u16_t i; |
| 100 | u8_t *ptr; |
| 101 | u8_t c; |
| 102 | |
| 103 | slipdev_char_put(SLIP_END); |
| 104 | |
| 105 | ptr = &uip_buf[UIP_LLH_LEN]; |
| 106 | for(i = 0; i < uip_len; ++i) { |
| 107 | if(i == UIP_TCPIP_HLEN) { |
| 108 | ptr = (char *)uip_appdata; |
| 109 | } |
| 110 | c = *ptr++; |
| 111 | switch(c) { |
| 112 | case SLIP_END: |
| 113 | slipdev_char_put(SLIP_ESC); |
| 114 | slipdev_char_put(SLIP_ESC_END); |
| 115 | break; |
| 116 | case SLIP_ESC: |
| 117 | slipdev_char_put(SLIP_ESC); |
| 118 | slipdev_char_put(SLIP_ESC_ESC); |
| 119 | break; |
| 120 | default: |
| 121 | slipdev_char_put(c); |
| 122 | break; |
| 123 | } |
| 124 | } |
| 125 | slipdev_char_put(SLIP_END); |
adamdunkels | d913334 | 2003-11-27 15:54:20 +0000 | [diff] [blame] | 126 | |
| 127 | return UIP_FW_OK; |
adamdunkels | b489e7a | 2003-10-14 11:12:50 +0000 | [diff] [blame] | 128 | } |
| 129 | /*-----------------------------------------------------------------------------------*/ |
| 130 | /** |
| 131 | * Poll the SLIP device for an available packet. |
| 132 | * |
| 133 | * This function will poll the SLIP device to see if a packet is |
| 134 | * available. It uses a buffer in which all avaliable bytes from the |
| 135 | * RS232 interface are read into. When a full packet has been read |
| 136 | * into the buffer, the packet is copied into the uip_buf buffer and |
| 137 | * the length of the packet is returned. |
| 138 | * |
| 139 | * \return The length of the packet placed in the uip_buf buffer, or |
| 140 | * zero if no packet is available. |
| 141 | */ |
| 142 | /*-----------------------------------------------------------------------------------*/ |
| 143 | u16_t |
| 144 | slipdev_poll(void) |
| 145 | { |
| 146 | u8_t c; |
| 147 | |
| 148 | while(slipdev_char_poll(&c)) { |
| 149 | switch(c) { |
| 150 | case SLIP_ESC: |
| 151 | lastc = c; |
| 152 | break; |
| 153 | |
| 154 | case SLIP_END: |
| 155 | lastc = c; |
| 156 | /* End marker found, we copy our input buffer to the uip_buf |
| 157 | buffer and return the size of the packet we copied. */ |
| 158 | memcpy(&uip_buf[UIP_LLH_LEN], slip_buf, len); |
| 159 | tmplen = len; |
| 160 | len = 0; |
| 161 | return tmplen; |
| 162 | |
| 163 | default: |
| 164 | if(lastc == SLIP_ESC) { |
| 165 | lastc = c; |
| 166 | /* Previous read byte was an escape byte, so this byte will be |
| 167 | interpreted differently from others. */ |
| 168 | switch(c) { |
| 169 | case SLIP_ESC_END: |
| 170 | c = SLIP_END; |
| 171 | break; |
| 172 | case SLIP_ESC_ESC: |
| 173 | c = SLIP_ESC; |
| 174 | break; |
| 175 | } |
| 176 | } else { |
| 177 | lastc = c; |
| 178 | } |
| 179 | |
| 180 | slip_buf[len] = c; |
| 181 | ++len; |
| 182 | |
| 183 | if(len > UIP_BUFSIZE) { |
| 184 | len = 0; |
| 185 | } |
| 186 | |
| 187 | break; |
| 188 | } |
| 189 | } |
| 190 | return 0; |
| 191 | } |
| 192 | /*-----------------------------------------------------------------------------------*/ |
| 193 | /** |
| 194 | * Initialize the SLIP module. |
| 195 | * |
| 196 | * This function does not initialize the underlying RS232 device, but |
| 197 | * only the SLIP part. |
| 198 | */ |
| 199 | /*-----------------------------------------------------------------------------------*/ |
| 200 | void |
| 201 | slipdev_init(void) |
| 202 | { |
| 203 | lastc = len = 0; |
| 204 | } |
| 205 | /*-----------------------------------------------------------------------------------*/ |
| 206 | |
| 207 | /** @} */ |
| 208 | /** @} */ |