oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 1 | /* www.mycal.com |
| 2 | *--------------------------------------------------------------------------- |
| 3 | * ahdlc.c - Ahdlc receive and transmit processor for PPP engine. |
| 4 | * |
| 5 | *--------------------------------------------------------------------------- |
| 6 | * Version |
| 7 | * 0.1 Original Version Jan 11, 1998 |
| 8 | * |
| 9 | *--------------------------------------------------------------------------- |
| 10 | * |
| 11 | * Copyright (C) 1998, Mycal Labs www.mycal.com |
| 12 | * |
| 13 | *--------------------------------------------------------------------------- |
| 14 | */ |
| 15 | /* |
| 16 | * Copyright (c) 2003, Mike Johnson, Mycal Labs, www.mycal.net |
| 17 | * All rights reserved. |
| 18 | * |
| 19 | * Redistribution and use in source and binary forms, with or without |
| 20 | * modification, are permitted provided that the following conditions |
| 21 | * are met: |
| 22 | * 1. Redistributions of source code must retain the above copyright |
| 23 | * notice, this list of conditions and the following disclaimer. |
| 24 | * 2. Redistributions in binary form must reproduce the above copyright |
| 25 | * notice, this list of conditions and the following disclaimer in the |
| 26 | * documentation and/or other materials provided with the distribution. |
| 27 | * 3. All advertising materials mentioning features or use of this software |
| 28 | * must display the following acknowledgement: |
| 29 | * This product includes software developed by Mike Johnson/Mycal Labs |
| 30 | * www.mycal.net. |
| 31 | * 4. The name of the author may not be used to endorse or promote |
| 32 | * products derived from this software without specific prior |
| 33 | * written permission. |
| 34 | * |
| 35 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| 36 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 37 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 38 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| 39 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 40 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| 41 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 42 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 43 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 44 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 45 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 46 | * |
| 47 | * This file is part of the Mycal Modified uIP TCP/IP stack. |
| 48 | * |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 49 | * $Id: ahdlc.c,v 1.3 2005/01/26 23:36:22 oliverschmidt Exp $ |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 50 | * |
| 51 | */ |
| 52 | |
| 53 | /* */ |
| 54 | /* include files */ |
| 55 | /* */ |
| 56 | |
| 57 | #include "uip.h" |
| 58 | #include "ppp.h" |
| 59 | |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 60 | #if 0 |
oliverschmidt | acc6395 | 2004-08-29 15:11:45 +0000 | [diff] [blame] | 61 | #define DEBUG1(x) |
| 62 | #else |
| 63 | #include <stdio.h> |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 64 | #define DEBUG1(x) debug_printf x |
oliverschmidt | acc6395 | 2004-08-29 15:11:45 +0000 | [diff] [blame] | 65 | #endif |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 66 | |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 67 | #define PACKET_TX_DEBUG 1 |
| 68 | |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 69 | /*--------------------------------------------------------------------------- |
| 70 | * ahdlc flags bit defins, for ahdlc_flags variable |
| 71 | ---------------------------------------------------------------------------*/ |
| 72 | /* Escaped mode bit */ |
| 73 | #define AHDLC_ESCAPED 0x1 |
| 74 | /* Frame is ready bit */ |
| 75 | #define AHDLC_RX_READY 0x2 |
| 76 | #define AHDLC_RX_ASYNC_MAP 0x4 |
| 77 | #define AHDLC_TX_ASYNC_MAP 0x8 |
| 78 | #define AHDLC_PFC 0x10 |
| 79 | #define AHDLC_ACFC 0x20 |
| 80 | |
| 81 | /*--------------------------------------------------------------------------- |
| 82 | * Private Local Globals |
| 83 | * 10 bytes - standard |
| 84 | * - with counters |
| 85 | ---------------------------------------------------------------------------*/ |
| 86 | /* running tx CRC */ |
| 87 | u16_t ahdlc_tx_crc; |
| 88 | /* running rx CRC */ |
| 89 | u16_t ahdlc_rx_crc; |
| 90 | /* number of rx bytes processed, cur frame */ |
| 91 | u16_t ahdlc_rx_count; |
| 92 | /* ahdlc state flags, see above */ |
| 93 | u8_t ahdlc_flags; |
| 94 | |
| 95 | /* |
| 96 | * The following can be optimized out |
| 97 | */ |
| 98 | u8_t *ahdlc_rx_buffer; /* What to do here? +++ */ |
| 99 | u16_t ahdlc_max_rx_buffer_size; |
| 100 | |
| 101 | /* |
| 102 | * Optional statistics counters. |
| 103 | */ |
| 104 | #ifdef AHDLC_COUNTERS |
| 105 | u8_t ahdlc_rx_tobig_error; |
| 106 | #endif |
| 107 | |
| 108 | /*---------------------------------------------------------------------------*/ |
| 109 | /* Simple and fast CRC16 routine for embedded processors. |
| 110 | * Just slightly slower than the table lookup method but consumes |
| 111 | * almost no space. Much faster and smaller than the loop and |
| 112 | * shift method that is widely used in the embedded space. |
| 113 | * Can be optimized even more in .ASM |
| 114 | * |
| 115 | * data = (crcvalue ^ inputchar) & 0xff; |
| 116 | * data = (data ^ (data << 4)) & 0xff; |
| 117 | * crc = (crc >> 8) ^ ((data << 8) ^ (data <<3) ^ (data >> 4)) |
| 118 | */ |
| 119 | /*---------------------------------------------------------------------------*/ |
| 120 | static u16_t |
| 121 | crcadd(u16_t crcvalue, u8_t c) |
| 122 | { |
| 123 | u16_t b; |
| 124 | |
| 125 | b = (crcvalue ^ c) & 0xFF; |
| 126 | b = (b ^ (b << 4) & 0xFF); |
| 127 | b = (b << 8) ^ (b << 3) ^ (b >> 4); |
| 128 | |
| 129 | return ((crcvalue >> 8) ^ b); |
| 130 | } |
| 131 | /*---------------------------------------------------------------------------*/ |
| 132 | /* ahdlc_init(buffer, buffersize) - this initializes the ahdlc engine to |
| 133 | * allow for rx frames. |
| 134 | */ |
| 135 | /*---------------------------------------------------------------------------*/ |
| 136 | void |
| 137 | ahdlc_init(u8_t *buffer, u16_t maxrxbuffersize) |
| 138 | { |
| 139 | ahdlc_flags = 0; |
| 140 | ahdlc_rx_buffer = buffer; |
| 141 | ahdlc_max_rx_buffer_size = maxrxbuffersize; |
| 142 | /* ahdlc_async_map = 0; */ |
| 143 | #ifdef AHDLC_COUNTERS |
| 144 | ahdlc_rx_tobig_error = 0; |
| 145 | #endif |
| 146 | } |
| 147 | /*---------------------------------------------------------------------------*/ |
| 148 | /* ahdlc_rx_ready() - resets the ahdlc engine to the beginning of frame |
| 149 | * state. |
| 150 | */ |
| 151 | /*---------------------------------------------------------------------------*/ |
| 152 | void |
| 153 | ahdlc_rx_ready(void) |
| 154 | { |
| 155 | ahdlc_rx_count = 0; |
| 156 | ahdlc_rx_crc = 0xffff; |
| 157 | ahdlc_flags |= AHDLC_RX_READY; |
| 158 | } |
| 159 | /*---------------------------------------------------------------------------*/ |
| 160 | /* ahdlc receive function - This routine processes incoming bytes and tries |
| 161 | * to build a PPP frame. |
| 162 | * |
| 163 | * Two possible reasons that ahdlc_rx will not process characters: |
| 164 | * o Buffer is locked - in this case ahdlc_rx returns 1, char |
| 165 | * sending routing should retry. |
| 166 | */ |
| 167 | /*---------------------------------------------------------------------------*/ |
| 168 | u8_t |
| 169 | ahdlc_rx(u8_t c) |
| 170 | { |
| 171 | static u16_t protocol; |
| 172 | |
| 173 | /* check to see if PPP packet is useable, we should have hardware |
| 174 | flow control set, but if host ignores it and sends us a char when |
| 175 | the PPP Receive packet is in use, discard the character. +++ */ |
| 176 | |
| 177 | if(ahdlc_flags & AHDLC_RX_READY) { |
| 178 | /* check to see if character is less than 0x20 hex we really |
| 179 | should set AHDLC_RX_ASYNC_MAP on by default and only turn it |
| 180 | off when it is negotiated off to handle some buggy stacks. */ |
| 181 | if((c < 0x20) && |
| 182 | ((ahdlc_flags & AHDLC_RX_ASYNC_MAP) == 0)) { |
| 183 | /* discard character */ |
| 184 | DEBUG1(("Discard because char is < 0x20 hex and asysnc map is 0\n")); |
| 185 | return 0; |
| 186 | } |
| 187 | /* are we in escaped mode? */ |
| 188 | if(ahdlc_flags & AHDLC_ESCAPED) { |
| 189 | /* set escaped to FALSE */ |
| 190 | ahdlc_flags &= ~AHDLC_ESCAPED; |
| 191 | |
| 192 | /* if value is 0x7e then silently discard and reset receive packet */ |
| 193 | if(c == 0x7e) { |
| 194 | ahdlc_rx_ready(); |
| 195 | return 0; |
| 196 | } |
| 197 | /* incomming char = itself xor 20 */ |
| 198 | c = c ^ 0x20; |
| 199 | } else if(c == 0x7e) { |
| 200 | /* handle frame end */ |
| 201 | if(ahdlc_rx_crc == CRC_GOOD_VALUE) { |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 202 | DEBUG1(("\nReceiving packet with good crc value, len %d\n",ahdlc_rx_count)); |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 203 | /* we hae a good packet, turn off CTS until we are done with |
| 204 | this packet */ |
| 205 | /*CTS_OFF();*/ |
| 206 | /* remove CRC bytes from packet */ |
| 207 | ahdlc_rx_count -= 2; |
| 208 | |
| 209 | /* lock PPP buffer */ |
| 210 | ahdlc_flags &= ~AHDLC_RX_READY; |
| 211 | /* |
| 212 | * upcall routine must fully process frame before return |
| 213 | * as returning signifies that buffer belongs to AHDLC again. |
| 214 | */ |
| 215 | if((c & 0x1) && (ahdlc_flags & PPP_PFC)) { |
| 216 | /* Send up packet */ |
| 217 | ppp_upcall((u16_t)ahdlc_rx_buffer[0], |
| 218 | (u8_t *)&ahdlc_rx_buffer[1], |
| 219 | (u16_t)(ahdlc_rx_count - 1)); |
| 220 | } else { |
| 221 | /* Send up packet */ |
| 222 | ppp_upcall((u16_t)(ahdlc_rx_buffer[0] << 8 | ahdlc_rx_buffer[1]), |
| 223 | (u8_t *)&ahdlc_rx_buffer[2], (u16_t)(ahdlc_rx_count - 2)); |
| 224 | } |
| 225 | ahdlc_rx_ready(); |
| 226 | return 0; |
| 227 | } else if(ahdlc_rx_count > 3) { |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 228 | DEBUG1(("\nReceiving packet with bad crc value, was 0x%04x len %d\n",ahdlc_rx_crc, ahdlc_rx_count)); |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 229 | #ifdef AHDLC_COUNTERS |
| 230 | ++ahdlc_crc_error; |
| 231 | #endif |
| 232 | /* Shouldn't we dump the packet and not pass it up? */ |
| 233 | /*ppp_upcall((u16_t)ahdlc_rx_buffer[0], |
| 234 | (u8_t *)&ahdlc_rx_buffer[0], (u16_t)(ahdlc_rx_count+2)); |
| 235 | dump_ppp_packet(&ahdlc_rx_buffer[0],ahdlc_rx_count);*/ |
| 236 | |
| 237 | } |
| 238 | ahdlc_rx_ready(); |
| 239 | return 0; |
| 240 | } else if(c == 0x7d) { |
| 241 | /* handle escaped chars*/ |
| 242 | ahdlc_flags |= PPP_ESCAPED; |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | /* try to store char if not to big */ |
| 247 | if(ahdlc_rx_count >= ahdlc_max_rx_buffer_size /*PPP_RX_BUFFER_SIZE*/) { |
| 248 | #ifdef AHDLC_COUNTERS |
| 249 | ++ahdlc_rx_tobig_error; |
| 250 | #endif |
| 251 | ahdlc_rx_ready(); |
| 252 | } else { |
| 253 | /* Add CRC in */ |
| 254 | ahdlc_rx_crc = crcadd(ahdlc_rx_crc, c); |
| 255 | /* do auto ACFC, if packet len is zero discard 0xff and 0x03 */ |
| 256 | if(ahdlc_rx_count == 0) { |
| 257 | if((c == 0xff) || (c == 0x03)) |
| 258 | return 0; |
| 259 | } |
| 260 | /* Store char */ |
| 261 | ppp_rx_buffer[ahdlc_rx_count++] = c; |
| 262 | } |
| 263 | } else { |
| 264 | /* we are busy and didn't process the character. */ |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 265 | DEBUG1(("Busy/not active\n")); |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 266 | return 1; |
| 267 | } |
| 268 | return 0; |
| 269 | } |
| 270 | /*---------------------------------------------------------------------------*/ |
| 271 | /* ahdlc_tx_char(char) - write a character to the serial device, |
| 272 | * escape if necessary. |
| 273 | * |
| 274 | * Relies on local global vars : ahdlc_tx_crc, ahdlc_flags. |
| 275 | * Modifies local global vars : ahdlc_tx_crc. |
| 276 | */ |
| 277 | /*---------------------------------------------------------------------------*/ |
| 278 | void |
| 279 | ahdlc_tx_char(u16_t protocol, u8_t c) |
| 280 | { |
| 281 | /* add in crc */ |
| 282 | ahdlc_tx_crc = crcadd(ahdlc_tx_crc, c); |
| 283 | /* |
| 284 | * See if we need to escape char, we always escape 0x7d and 0x7e, in the case |
| 285 | * of char < 0x20 we only support async map of default or none, so escape if |
| 286 | * ASYNC map is not set. We may want to modify this to support a bitmap set |
| 287 | * ASYNC map. |
| 288 | */ |
| 289 | if((c == 0x7d) || (c == 0x7e) || |
| 290 | ((c < 0x20) && ((protocol == LCP) || |
| 291 | (ahdlc_flags & PPP_TX_ASYNC_MAP) == 0))) { |
| 292 | /* send escape char and xor byte by 0x20 */ |
| 293 | ppp_arch_putchar(0x7d); |
| 294 | c ^= 0x20; |
| 295 | } |
| 296 | ppp_arch_putchar(c); |
| 297 | } |
| 298 | /*---------------------------------------------------------------------------*/ |
| 299 | /* ahdlc_tx(protocol,buffer,len) - Transmit a PPP frame. |
| 300 | * Buffer contains protocol data, ahdlc_tx addes address, control and |
| 301 | * protocol data. |
| 302 | * |
| 303 | * Relies on local global vars : ahdlc_tx_crc, ahdlc_flags. |
| 304 | * Modifies local global vars : ahdlc_tx_crc. |
| 305 | */ |
| 306 | /*---------------------------------------------------------------------------*/ |
| 307 | u8_t |
| 308 | ahdlc_tx(u16_t protocol, u8_t *header, u8_t *buffer, |
| 309 | u16_t headerlen, u16_t datalen) |
| 310 | { |
| 311 | u16_t i; |
| 312 | u8_t c; |
| 313 | |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 314 | DEBUG1(("\nAHDLC_TX - transmit frame, protocol 0x%04x, length %d\n",protocol,datalen+headerlen)); |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 315 | |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 316 | #if PACKET_TX_DEBUG |
| 317 | DEBUG1(("\n")); |
| 318 | for(i = 0; i < headerlen; ++i) { |
| 319 | DEBUG1(("0x%02x ", header[i])); |
| 320 | } |
| 321 | for(i = 0; i < datalen; ++i) { |
| 322 | DEBUG1(("0x%02x ", buffer[i])); |
| 323 | } |
| 324 | DEBUG1(("\n\n")); |
| 325 | #endif |
| 326 | |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 327 | /* Check to see that physical layer is up, we can assume is some |
| 328 | cases */ |
| 329 | |
| 330 | /* write leading 0x7e */ |
| 331 | ppp_arch_putchar(0x7e); |
| 332 | |
| 333 | /* set initial CRC value */ |
| 334 | ahdlc_tx_crc = 0xffff; |
oliverschmidt | 85729cb | 2005-01-26 23:36:22 +0000 | [diff] [blame] | 335 | /* send HDLC control and address if not disabled or of LCP frame type */ |
oliverschmidt | 3396e9a | 2004-08-20 12:29:54 +0000 | [diff] [blame] | 336 | /*if((0==(ahdlc_flags & PPP_ACFC)) || ((0xc0==buffer[0]) && (0x21==buffer[1]))) */ |
| 337 | if((0 == (ahdlc_flags & PPP_ACFC)) || (protocol == LCP)) { |
| 338 | ahdlc_tx_char(protocol, 0xff); |
| 339 | ahdlc_tx_char(protocol, 0x03); |
| 340 | } |
| 341 | |
| 342 | /* Write Protocol */ |
| 343 | ahdlc_tx_char(protocol,(u8_t)(protocol >> 8)); |
| 344 | ahdlc_tx_char(protocol,(u8_t)(protocol & 0xff)); |
| 345 | |
| 346 | /* write header if it exists */ |
| 347 | for(i = 0; i < headerlen; ++i) { |
| 348 | /* Get next byte from buffer */ |
| 349 | c = header[i]; |
| 350 | /* Write it...*/ |
| 351 | ahdlc_tx_char(protocol, c); |
| 352 | } |
| 353 | |
| 354 | /* Write frame bytes */ |
| 355 | for(i = 0; i < datalen; ++i) { |
| 356 | /* Get next byte from buffer */ |
| 357 | c = buffer[i]; |
| 358 | /* Write it...*/ |
| 359 | ahdlc_tx_char(protocol, c); |
| 360 | } |
| 361 | |
| 362 | /* send crc, lsb then msb */ |
| 363 | i = ahdlc_tx_crc ^ 0xffff; |
| 364 | ahdlc_tx_char(protocol, (u8_t)(i & 0xff)); |
| 365 | ahdlc_tx_char(protocol, (u8_t)((i >> 8) & 0xff)); |
| 366 | |
| 367 | /* write trailing 0x7e, probably not needed but it doesn't hurt*/ |
| 368 | ppp_arch_putchar(0x7e); |
| 369 | return 0; |
| 370 | } |
| 371 | /*---------------------------------------------------------------------------*/ |