1 /** 2 * @file 3 * SLIP Interface 4 * 5 */ 6 7 /* 8 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * This file is built upon the file: src/arch/rtxc/netif/sioslip.c 36 * 37 * Author: Magnus Ivarsson <magnus.ivarsson(at)volvo.com> 38 */ 39 40 /* 41 * This is an arch independent SLIP netif. The specific serial hooks must be 42 * provided by another file. They are sio_open, sio_read/sio_tryread and sio_send 43 */ 44 45 #include "netif/slipif.h" 46 #include "lwip/opt.h" 47 48 #if LWIP_HAVE_SLIPIF 49 50 #include "lwip/def.h" 51 #include "lwip/pbuf.h" 52 #include "lwip/sys.h" 53 #include "lwip/stats.h" 54 #include "lwip/snmp.h" 55 #include "lwip/sio.h" 56 57 #define SLIP_BLOCK 1 58 #define SLIP_DONTBLOCK 0 59 60 #define SLIP_END 0300 /* 0xC0 */ 61 #define SLIP_ESC 0333 /* 0xDB */ 62 #define SLIP_ESC_END 0334 /* 0xDC */ 63 #define SLIP_ESC_ESC 0335 /* 0xDD */ 64 65 #define SLIP_MAX_SIZE 1500 66 67 enum slipif_recv_state { 68 SLIP_RECV_NORMAL, 69 SLIP_RECV_ESCAPE, 70 }; 71 72 struct slipif_priv { 73 sio_fd_t sd; 74 /* q is the whole pbuf chain for a packet, p is the current pbuf in the chain */ 75 struct pbuf *p, *q; 76 enum slipif_recv_state state; 77 u16_t i, recved; 78 }; 79 80 /** 81 * Send a pbuf doing the necessary SLIP encapsulation 82 * 83 * Uses the serial layer's sio_send() 84 * 85 * @param netif the lwip network interface structure for this slipif 86 * @param p the pbuf chaing packet to send 87 * @param ipaddr the ip address to send the packet to (not used for slipif) 88 * @return always returns ERR_OK since the serial layer does not provide return values 89 */ 90 err_t 91 slipif_output(struct netif *netif, struct pbuf *p, ip_addr_t *ipaddr) 92 { 93 struct slipif_priv *priv; 94 struct pbuf *q; 95 u16_t i; 96 u8_t c; 97 98 LWIP_ASSERT("netif != NULL", (netif != NULL)); 99 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL)); 100 LWIP_ASSERT("p != NULL", (p != NULL)); 101 102 LWIP_UNUSED_ARG(ipaddr); 103 104 priv = netif->state; 105 106 /* Send pbuf out on the serial I/O device. */ 107 sio_send(SLIP_END, priv->sd); 108 109 for (q = p; q != NULL; q = q->next) { 110 for (i = 0; i < q->len; i++) { 111 c = ((u8_t *)q->payload)[i]; 112 switch (c) { 113 case SLIP_END: 114 sio_send(SLIP_ESC, priv->sd); 115 sio_send(SLIP_ESC_END, priv->sd); 116 break; 117 case SLIP_ESC: 118 sio_send(SLIP_ESC, priv->sd); 119 sio_send(SLIP_ESC_ESC, priv->sd); 120 break; 121 default: 122 sio_send(c, priv->sd); 123 break; 124 } 125 } 126 } 127 sio_send(SLIP_END, priv->sd); 128 return ERR_OK; 129 } 130 131 /** 132 * Static function for easy use of blockig or non-blocking 133 * sio_read 134 * 135 * @param fd serial device handle 136 * @param data pointer to data buffer for receiving 137 * @param len maximum length (in bytes) of data to receive 138 * @param block if 1, call sio_read; if 0, call sio_tryread 139 * @return return value of sio_read of sio_tryread 140 */ 141 static u32_t 142 slip_sio_read(sio_fd_t fd, u8_t* data, u32_t len, u8_t block) 143 { 144 if (block) { 145 return sio_read(fd, data, len); 146 } else { 147 return sio_tryread(fd, data, len); 148 } 149 } 150 151 /** 152 * Handle the incoming SLIP stream character by character 153 * 154 * Poll the serial layer by calling sio_read() or sio_tryread(). 155 * 156 * @param netif the lwip network interface structure for this slipif 157 * @param block if 1, block until data is received; if 0, return when all data 158 * from the buffer is received (multiple calls to this function will 159 * return a complete packet, NULL is returned before - used for polling) 160 * @return The IP packet when SLIP_END is received 161 */ 162 static struct pbuf * 163 slipif_input(struct netif *netif, u8_t block) 164 { 165 struct slipif_priv *priv; 166 u8_t c; 167 struct pbuf *t; 168 169 LWIP_ASSERT("netif != NULL", (netif != NULL)); 170 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL)); 171 172 priv = netif->state; 173 174 while (slip_sio_read(priv->sd, &c, 1, block) > 0) { 175 switch (priv->state) { 176 case SLIP_RECV_NORMAL: 177 switch (c) { 178 case SLIP_END: 179 if (priv->recved > 0) { 180 /* Received whole packet. */ 181 /* Trim the pbuf to the size of the received packet. */ 182 pbuf_realloc(priv->q, priv->recved); 183 184 LINK_STATS_INC(link.recv); 185 186 LWIP_DEBUGF(SLIP_DEBUG, ("slipif: Got packet\n")); 187 t = priv->q; 188 priv->p = priv->q = NULL; 189 priv->i = priv->recved = 0; 190 return t; 191 } 192 continue; 193 case SLIP_ESC: 194 priv->state = SLIP_RECV_ESCAPE; 195 continue; 196 } 197 break; 198 case SLIP_RECV_ESCAPE: 199 switch (c) { 200 case SLIP_ESC_END: 201 c = SLIP_END; 202 break; 203 case SLIP_ESC_ESC: 204 c = SLIP_ESC; 205 break; 206 } 207 priv->state = SLIP_RECV_NORMAL; 208 /* FALLTHROUGH */ 209 } 210 211 /* byte received, packet not yet completely received */ 212 if (priv->p == NULL) { 213 /* allocate a new pbuf */ 214 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: alloc\n")); 215 priv->p = pbuf_alloc(PBUF_LINK, (PBUF_POOL_BUFSIZE - PBUF_LINK_HLEN), PBUF_POOL); 216 217 if (priv->p == NULL) { 218 LINK_STATS_INC(link.drop); 219 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_input: no new pbuf! (DROP)\n")); 220 /* don't process any further since we got no pbuf to receive to */ 221 break; 222 } 223 224 if (priv->q != NULL) { 225 /* 'chain' the pbuf to the existing chain */ 226 pbuf_cat(priv->q, priv->p); 227 } else { 228 /* p is the first pbuf in the chain */ 229 priv->q = priv->p; 230 } 231 } 232 233 /* this automatically drops bytes if > SLIP_MAX_SIZE */ 234 if ((priv->p != NULL) && (priv->recved <= SLIP_MAX_SIZE)) { 235 ((u8_t *)priv->p->payload)[priv->i] = c; 236 priv->recved++; 237 priv->i++; 238 if (priv->i >= priv->p->len) { 239 /* on to the next pbuf */ 240 priv->i = 0; 241 if (priv->p->next != NULL && priv->p->next->len > 0) { 242 /* p is a chain, on to the next in the chain */ 243 priv->p = priv->p->next; 244 } else { 245 /* p is a single pbuf, set it to NULL so next time a new 246 * pbuf is allocated */ 247 priv->p = NULL; 248 } 249 } 250 } 251 } 252 253 return NULL; 254 } 255 256 #if !NO_SYS 257 /** 258 * The SLIP input thread. 259 * 260 * Feed the IP layer with incoming packets 261 * 262 * @param nf the lwip network interface structure for this slipif 263 */ 264 static void 265 slipif_loop_thread(void *nf) 266 { 267 struct pbuf *p; 268 struct netif *netif = (struct netif *)nf; 269 270 while (1) { 271 p = slipif_input(netif, SLIP_BLOCK); 272 if (p != NULL) { 273 if (netif->input(p, netif) != ERR_OK) { 274 pbuf_free(p); 275 p = NULL; 276 } 277 } 278 } 279 } 280 #endif /* !NO_SYS */ 281 282 /** 283 * SLIP netif initialization 284 * 285 * Call the arch specific sio_open and remember 286 * the opened device in the state field of the netif. 287 * 288 * @param netif the lwip network interface structure for this slipif 289 * @return ERR_OK if serial line could be opened, 290 * ERR_MEM if no memory could be allocated, 291 * ERR_IF is serial line couldn't be opened 292 * 293 * @note netif->num must contain the number of the serial port to open 294 * (0 by default) 295 */ 296 err_t 297 slipif_init(struct netif *netif) 298 { 299 struct slipif_priv *priv; 300 301 LWIP_DEBUGF(SLIP_DEBUG, ("slipif_init: netif->num=%"U16_F"\n", (u16_t)netif->num)); 302 303 /* Allocate private data */ 304 priv = mem_malloc(sizeof(struct slipif_priv)); 305 if (!priv) { 306 return ERR_MEM; 307 } 308 309 netif->name[0] = 's'; 310 netif->name[1] = 'l'; 311 netif->output = slipif_output; 312 netif->mtu = SLIP_MAX_SIZE; 313 netif->flags |= NETIF_FLAG_POINTTOPOINT; 314 315 /* Try to open the serial port (netif->num contains the port number). */ 316 priv->sd = sio_open(netif->num); 317 if (!priv->sd) { 318 /* Opening the serial port failed. */ 319 mem_free(priv); 320 return ERR_IF; 321 } 322 323 /* Initialize private data */ 324 priv->p = NULL; 325 priv->q = NULL; 326 priv->state = SLIP_RECV_NORMAL; 327 priv->i = 0; 328 priv->recved = 0; 329 330 netif->state = priv; 331 332 /* initialize the snmp variables and counters inside the struct netif 333 * ifSpeed: no assumption can be made without knowing more about the 334 * serial line! 335 */ 336 NETIF_INIT_SNMP(netif, snmp_ifType_slip, 0); 337 338 /* Create a thread to poll the serial line. */ 339 sys_thread_new(SLIPIF_THREAD_NAME, slipif_loop_thread, netif, 340 SLIPIF_THREAD_STACKSIZE, SLIPIF_THREAD_PRIO); 341 return ERR_OK; 342 } 343 344 /** 345 * Polls the serial device and feeds the IP layer with incoming packets. 346 * 347 * @param netif The lwip network interface structure for this slipif 348 */ 349 void 350 slipif_poll(struct netif *netif) 351 { 352 struct pbuf *p; 353 struct slipif_priv *priv; 354 355 LWIP_ASSERT("netif != NULL", (netif != NULL)); 356 LWIP_ASSERT("netif->state != NULL", (netif->state != NULL)); 357 358 priv = netif->state; 359 360 while ((p = slipif_input(netif, SLIP_DONTBLOCK)) != NULL) { 361 if (netif->input(p, netif) != ERR_OK) { 362 pbuf_free(p); 363 } 364 } 365 } 366 367 #endif /* LWIP_HAVE_SLIPIF */ 368
