main.c

   1 /*
   2  * Copyright (c) 2011, Olivier MATZ <zer0@droids-corp.org>
   3  * All rights reserved.
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  *
   7  *     * Redistributions of source code must retain the above copyright
   8  *       notice, this list of conditions and the following disclaimer.
   9  *     * Redistributions in binary form must reproduce the above copyright
  10  *       notice, this list of conditions and the following disclaimer in the
  11  *       documentation and/or other materials provided with the distribution.
  12  *     * Neither the name of the University of California, Berkeley nor the
  13  *       names of its contributors may be used to endorse or promote products
  14  *       derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
  17  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  25  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include <aversive.h>
  29 #include <aversive/queue.h>
  30 #include <aversive/endian.h>
  31 #include <aversive/wait.h>
  32 #include <aversive/error.h>
  33
  34 #include <uart.h>
  35
  36 #include <stdio.h>
  37 #include <string.h>
  38 #include <stdint.h>
  39 #include <inttypes.h>
  40 #include <stdlib.h>
  41 #include <stdarg.h>
  42 #include <errno.h>
  43 #include <ctype.h>
  44
  45 #include <scheduler.h>
  46 #include <clock_time.h>
  47 #include <parse.h>
  48 #include <rdline.h>
  49 #include <timer.h>
  50
  51 #include "xbee_neighbor.h"
  52 #include "xbee_atcmd.h"
  53 #include "xbee_stats.h"
  54 #include "xbee_buf.h"
  55 #include "xbee_proto.h"
  56 #include "xbee.h"
  57 #include "cmdline.h"
  58 #include "callout.h"
  59 #include "rc_proto.h"
  60 #include "main.h"
  61
  62 struct xbeeboard xbeeboard;
  63 volatile uint16_t global_ms;
  64 struct callout_manager cm;
  65
  66 #define TIMEOUT_MS 1000
  67
  68 /* global xbee device */
  69 struct xbee_dev *xbee_dev;
  70
  71 /* events */
  72 //static struct event stdin_read_event, xbee_read_event;
  73
  74 /* parameters */
  75 int xbee_raw = 0;
  76 int xbee_hexdump = 0;
  77 int xbee_debug = 0;
  78
  79 int xbee_cmdline_input_enabled = 1;
  80
  81 static struct xbee_ctx xbee_ctx[XBEE_MAX_CHANNEL];
  82
  83 static void hexdump(const char *title, const void *buf, unsigned int len)
  84 {
  85         unsigned int i, out, ofs;
  86         const unsigned char *data = buf;
  87 #define LINE_LEN 80
  88         char line[LINE_LEN];    /* space needed 8+16*3+3+16 == 75 */
  89
  90         printf_P(PSTR("%s at [%p], len=%d\n"), title, data, len);
  91         ofs = 0;
  92         while (ofs < len) {
  93                 /* format 1 line in the buffer, then use printk to print them */
  94                 out = snprintf_P(line, LINE_LEN, PSTR("%08X"), ofs);
  95                 for (i=0; ofs+i < len && i<16; i++)
  96                         out += snprintf_P(line+out, LINE_LEN - out,
  97                                           PSTR(" %02X"),
  98                                           data[ofs+i]&0xff);
  99                 for (;i<=16;i++)
 100                         out += snprintf(line+out, LINE_LEN - out, "   ");
 101                 for (i=0; ofs < len && i<16; i++, ofs++) {
 102                         unsigned char c = data[ofs];
 103                         if (!isascii(c) || !isprint(c))
 104                                 c = '.';
 105                         out += snprintf_P(line+out,
 106                                           LINE_LEN - out,
 107                                           PSTR("%c"), c);
 108                 }
 109                 printf_P(PSTR("%s\r\n"), line);
 110         }
 111 }
 112
 113 static int parse_xmit_status(struct xbee_ctx *ctx,
 114                              struct xbee_xmit_status_hdr *frame, unsigned len)
 115 {
 116         if (ctx == NULL) {
 117                 printf_P(PSTR("no context\r\n"));
 118                 return -1;
 119         }
 120
 121         /* see if it matches a xmit query (atcmd_query must be NULL) */
 122         if (ctx->atcmd_query[0] != '\0') {
 123                 printf_P(PSTR("invalid response 2\r\n"));
 124                 return -1;
 125         }
 126
 127         /* XXX use defines for these values */
 128         if (frame->delivery_status == 0x00)
 129                 printf_P(PSTR("Success\r\n"));
 130         else if (frame->delivery_status == 0x01)
 131                 printf_P(PSTR("MAC ACK Failure\r\n"));
 132         else if (frame->delivery_status == 0x15)
 133                 printf_P(PSTR("Invalid destination endpoint\r\n"));
 134         else if (frame->delivery_status == 0x21)
 135                 printf_P(PSTR("Network ACK Failure\r\n"));
 136         else if (frame->delivery_status == 0x25)
 137                 printf_P(PSTR("Route Not Found\r\n"));
 138
 139         return 0;
 140 }
 141
 142 static int dump_atcmd(struct xbee_ctx *ctx, struct xbee_atresp_hdr *frame,
 143                unsigned len)
 144 {
 145         char atcmd_str[3];
 146         struct xbee_atcmd_pgm *cmd_pgm;
 147         struct xbee_atcmd cmd;
 148         union {
 149                 uint8_t u8;
 150                 uint16_t u16;
 151                 uint32_t u32;
 152                 int16_t s16;
 153         } __attribute__((packed)) *result;
 154
 155         if (ctx == NULL) {
 156                 printf_P(PSTR("no context\r\n"));
 157                 return -1;
 158         }
 159
 160         /* get AT command from frame */
 161         memcpy(atcmd_str, &frame->cmd, 2);
 162         atcmd_str[2] = '\0';
 163
 164         /* see if it matches query */
 165         if (memcmp(atcmd_str, ctx->atcmd_query, 2)) {
 166                 printf_P(PSTR("invalid response <%c%c><%s><%s>\r\n"),
 167                          frame->cmd & 0xFF,
 168                          (frame->cmd >> 8) & 0xFF,
 169                          atcmd_str, ctx->atcmd_query);
 170                 return -1;
 171         }
 172
 173         /* see if it exists */
 174         cmd_pgm = xbee_atcmd_lookup_name(atcmd_str);
 175         if (cmd_pgm == NULL) {
 176                 printf_P(PSTR("unknown response\r\n"));
 177                 return -1;
 178         }
 179         memcpy_P(&cmd, cmd_pgm, sizeof(cmd));
 180
 181         /* bad status */
 182         if (frame->status == 1) {
 183                 printf_P(PSTR("Status is error\r\n"));
 184                 return -1;
 185         }
 186         else if (frame->status == 2) {
 187                 printf_P(PSTR("Invalid command\r\n"));
 188                 return -1;
 189         }
 190         else if (frame->status == 3) {
 191                 printf_P(PSTR("Invalid parameter\r\n"));
 192                 return -1;
 193         }
 194         else if (frame->status != 0) {
 195                 printf_P(PSTR("Unknown status error %d\r\n"), frame->status);
 196                 return -1;
 197         }
 198
 199         /* callback */
 200         if (ctx->func != NULL)
 201                 ctx->func(frame, len, ctx->arg);
 202
 203         /* dump frame */
 204         result = (void *)frame->data;
 205         len -= offsetof(struct xbee_atresp_hdr, data);
 206         if (cmd.flags & XBEE_ATCMD_F_PARAM_U8 && len == sizeof(uint8_t))
 207                 printf_P(PSTR("<%s> is 0x%x\r\n"), atcmd_str, result->u8);
 208         else if (cmd.flags & XBEE_ATCMD_F_PARAM_U16 && len == sizeof(uint16_t))
 209                 printf_P(PSTR("<%s> is 0x%x\r\n"),
 210                          atcmd_str,
 211                          ntohs(result->u16));
 212         else if (cmd.flags & XBEE_ATCMD_F_PARAM_U32 && len == sizeof(uint32_t))
 213                 printf_P(PSTR("<%s> is 0x%"PRIx32"\r\n"),
 214                          atcmd_str,
 215                          ntohl(result->u32));
 216         else if (cmd.flags & XBEE_ATCMD_F_PARAM_S16 && len == sizeof(int16_t))
 217                 printf_P(PSTR("<%s> is %d\r\n"), atcmd_str, ntohs(result->s16));
 218         else if (len == 0)
 219                 printf_P(PSTR("no data, status ok\r\n"));
 220         else
 221                 hexdump("atcmd answer", frame->data, len);
 222
 223
 224         return 0;
 225 }
 226
 227
 228 int xbee_recv_data(struct xbee_recv_hdr *recvframe, unsigned len)
 229 {
 230         int datalen = len - sizeof(*recvframe);
 231         struct rc_proto_hdr *rch = (struct rc_proto_hdr *) &recvframe->data;
 232
 233         if (datalen < sizeof(struct rc_proto_hdr))
 234                 return -1;
 235
 236         switch (rch->type) {
 237                 case RC_PROTO_TYPE_CHANNEL:
 238                         if (datalen != sizeof(struct rc_proto_channel))
 239                                 return -1;
 240                         break;
 241                 case RC_PROTO_TYPE_RANGE: {
 242                         struct rc_proto_range *rcr =
 243                                 (struct rc_proto_range *) recvframe->data;
 244
 245                         if (datalen != sizeof(struct rc_proto_range))
 246                                 return -1;
 247
 248                         if (rcr->power_level >= MAX_POWER_LEVEL)
 249                                 return -1;
 250
 251                         rc_proto_rx_range(rcr->power_level);
 252
 253                         break;
 254                 }
 255                 default:
 256                         return -1;
 257         }
 258
 259         return 0;
 260 }
 261
 262 /* socat /dev/ttyUSB0,raw,echo=0,b115200 /dev/ttyACM1,raw,echo=0,b115200 */
 263 void xbee_rx(struct xbee_dev *dev, int channel, int type,
 264              void *frame, unsigned len, void *opaque)
 265 {
 266         struct xbee_ctx *ctx = opaque;
 267         int do_hexdump = xbee_hexdump;
 268
 269         if (xbee_debug)
 270                 printf_P(PSTR("type=0x%x, channel=%d, ctx=%p\r\n"),
 271                          type, channel, ctx);
 272
 273         /* if ctx is !NULL, it is an answer to a query */
 274         if (ctx != NULL) {
 275                 /* XXX only delete timeout if answer matched */
 276                 xbee_unload_timeout(ctx);
 277                 if (xbee_debug && ctx->atcmd_query)
 278                         printf_P(PSTR("Received answer to query <%c%c>\r\n"),
 279                                  ctx->atcmd_query[0], ctx->atcmd_query[1]);
 280         }
 281
 282         /* some additional checks before sending */
 283         switch (type) {
 284                 case XBEE_TYPE_MODEM_STATUS: {
 285                         printf_P(PSTR("Received Modem Status frame\r\n"));
 286                         break;
 287                 }
 288
 289                 case XBEE_TYPE_RMT_ATRESP: {
 290                         union {
 291                                 uint64_t u64;
 292                                 struct {
 293 #if BYTE_ORDER == LITTLE_ENDIAN
 294                                         uint32_t low;
 295                                         uint32_t high;
 296 #else
 297                                         uint32_t high;
 298                                         uint32_t low;
 299 #endif
 300                                 } u32;
 301                         } addr;
 302                         memcpy(&addr, frame, sizeof(addr));
 303                         addr.u64 = ntohll(addr.u64);
 304                         printf_P(PSTR("from remote address %"PRIx32"%"PRIx32"\r\n"),
 305                                  addr.u32.high, addr.u32.low);
 306
 307                         /* this answer contains an atcmd answer at offset 10 */
 308                         if (dump_atcmd(ctx, frame + 10, len - 10) < 0)
 309                                 do_hexdump = 1;
 310                         break;
 311                 }
 312                 case XBEE_TYPE_ATRESP: {
 313                         if (dump_atcmd(ctx, frame, len) < 0)
 314                                 do_hexdump = 1;
 315                         break;
 316                 }
 317
 318                 case XBEE_TYPE_XMIT_STATUS: {
 319                         if (parse_xmit_status(ctx, frame, len) < 0)
 320                                 do_hexdump = 1;
 321                         break;
 322                 }
 323
 324                 case XBEE_TYPE_RECV: {
 325                         if (xbee_recv_data(frame, len) < 0)
 326                                 do_hexdump = 1;
 327                         break;
 328                 }
 329
 330                 case XBEE_TYPE_ATCMD:
 331                 case XBEE_TYPE_ATCMD_Q:
 332                 case XBEE_TYPE_XMIT:
 333                 case XBEE_TYPE_EXPL_XMIT:
 334                 case XBEE_TYPE_RMT_ATCMD:
 335                 case XBEE_TYPE_EXPL_RECV:
 336                 case XBEE_TYPE_NODE_ID:
 337                 default:
 338                         printf_P(PSTR("Invalid frame\r\n"));
 339                         do_hexdump = 1;
 340                         break;
 341         }
 342
 343         if (do_hexdump)
 344                 hexdump("undecoded rx frame", frame, len);
 345
 346         /* restart command line if it was a blocking query */
 347         if (ctx != NULL) {
 348                 xbee_unregister_channel(dev, channel);
 349                 if (ctx->foreground) {
 350                         xbee_stdin_enable();
 351                         rdline_newline(&xbeeboard.rdl, xbeeboard.prompt);
 352                 }
 353         }
 354 }
 355
 356 static int xbeeapp_send(struct xbee_ctx *ctx, int type, void *buf, unsigned len,
 357                         int foreground)
 358 {
 359         int ret;
 360         int channel;
 361
 362         if (len > XBEE_MAX_FRAME_LEN) {
 363                 printf_P(PSTR("frame too large\r\n"));
 364                 return -1;
 365         }
 366
 367         /* register a channel */
 368         channel = xbee_register_channel(xbee_dev, XBEE_CHANNEL_ANY,
 369                                         xbee_rx, NULL);
 370         if (channel < 0) {
 371                 printf_P(PSTR("cannot send: no free channel\r\n"));
 372                 return -1;
 373         }
 374
 375         /* copy context in the static struct table (avoiding a malloc) */
 376         memcpy(&xbee_ctx[channel], ctx, sizeof(*ctx));
 377         ctx = &xbee_ctx[channel];
 378         xbee_set_opaque(xbee_dev, channel, ctx);
 379
 380         if (xbee_debug)
 381                 printf_P(PSTR("send frame channel=%d type=0x%x len=%d\r\n"),
 382                          channel, type, len);
 383         if (xbee_hexdump)
 384                 hexdump("xmit frame", buf, len);
 385
 386         /* transmit the frame on this channel */
 387         ret = xbee_proto_xmit(xbee_dev, channel, type, buf,
 388                               len);
 389         if (ret < 0) {
 390                 printf_P(PSTR("cannot send\r\n"));
 391                 xbee_unregister_channel(xbee_dev, channel);
 392                 return -1;
 393         }
 394
 395         ctx->channel = channel;
 396         xbee_load_timeout(ctx);   /* load a timeout event */
 397
 398         /* suspend command line until we have answer or timeout */
 399         if (foreground) {
 400                 ctx->foreground = 1;
 401                 rdline_stop(&xbeeboard.rdl); /* don't display prompt when return */
 402                 xbee_stdin_disable();  /* unload file descriptor polling */
 403         }
 404
 405         return 0;
 406 }
 407
 408 /* send an AT command with parameters filled by caller. Disable
 409  * command line until we get the answer or until a timeout occurs */
 410 int xbeeapp_send_atcmd(const char *atcmd_str,
 411                        void *param, unsigned param_len, int foreground,
 412                        int (*func)(void *frame, unsigned len, void *arg), void *arg)
 413 {
 414         struct xbee_ctx ctx;
 415         struct {
 416                 struct xbee_atcmd_hdr atcmd;
 417                 char buf[XBEE_MAX_FRAME_LEN];
 418         } __attribute__((packed)) frame;
 419
 420         memset(&ctx, 0, sizeof(ctx));
 421         ctx.atcmd_query[0] = atcmd_str[0];
 422         ctx.atcmd_query[1] = atcmd_str[1];
 423         ctx.func = func;
 424         ctx.arg = arg;
 425
 426         memcpy(&frame.atcmd.cmd, atcmd_str, 2);
 427         memcpy(&frame.buf, param, param_len);
 428
 429         if (xbeeapp_send(&ctx, XBEE_TYPE_ATCMD, &frame,
 430                          sizeof(struct xbee_atcmd_hdr) +
 431                          param_len, foreground) < 0) {
 432                 return -1;
 433         }
 434
 435         return 0;
 436 }
 437
 438 int xbeeapp_send_msg(uint64_t addr, void *data,
 439                      unsigned data_len, int foreground)
 440 {
 441         struct xbee_ctx ctx;
 442         struct {
 443                 struct xbee_xmit_hdr xmit;
 444                 char buf[XBEE_MAX_FRAME_LEN];
 445         } __attribute__((packed)) frame;
 446
 447         memset(&ctx, 0, sizeof(ctx));
 448         ctx.atcmd_query[0] = '\0';
 449
 450         frame.xmit.dstaddr = htonll(addr);
 451         frame.xmit.reserved = htons(0xFFFE);
 452         frame.xmit.bcast_radius = 0;
 453         frame.xmit.opts = 0;
 454         memcpy(&frame.buf, data, data_len);
 455
 456         if (xbeeapp_send(&ctx, XBEE_TYPE_XMIT, &frame,
 457                          sizeof(struct xbee_xmit_hdr) +
 458                          data_len, foreground) < 0) {
 459                 return -1;
 460         }
 461
 462         return 0;
 463 }
 464
 465 void xbee_stdin_enable(void)
 466 {
 467         xbee_cmdline_input_enabled = 1;
 468 }
 469
 470 void xbee_stdin_disable(void)
 471 {
 472         xbee_cmdline_input_enabled = 0;
 473 }
 474
 475 static void evt_timeout(struct callout_manager *cm, struct callout *clt,
 476                         void *arg)
 477 {
 478         struct xbee_ctx *ctx = arg;
 479
 480         printf_P(PSTR("Timeout\r\n"));
 481
 482         /* restart command line */
 483         xbee_stdin_enable();
 484         rdline_newline(&xbeeboard.rdl, xbeeboard.prompt);
 485
 486         /* free event */
 487         xbee_unregister_channel(xbee_dev, ctx->channel);
 488 }
 489
 490 void xbee_load_timeout(struct xbee_ctx *ctx)
 491 {
 492         callout_reset(&cm, &ctx->timeout, TIMEOUT_MS, SINGLE, evt_timeout, ctx);
 493 }
 494
 495 void xbee_unload_timeout(struct xbee_ctx *ctx)
 496 {
 497         callout_stop(&cm, &ctx->timeout);
 498 }
 499
 500 void bootloader(void)
 501 {
 502 #define BOOTLOADER_ADDR 0x1f800
 503         if (pgm_read_byte_far(BOOTLOADER_ADDR) == 0xff) {
 504                 printf_P(PSTR("Bootloader is not present\r\n"));
 505                 return;
 506         }
 507         cli();
 508         /* ... very specific :( */
 509         EIMSK = 0;
 510         SPCR = 0;
 511         TWCR = 0;
 512         ACSR = 0;
 513         ADCSRA = 0;
 514
 515         __asm__ __volatile__ ("ldi r31,0xf0\n");
 516         __asm__ __volatile__ ("ldi r30,0x00\n");
 517         __asm__ __volatile__ ("ijmp\n");
 518
 519         /* never returns */
 520 }
 521
 522 void xbee_mainloop(void)
 523 {
 524         while (1) {
 525                 callout_manage(&cm);
 526
 527                 if (xbee_raw) {
 528                         int16_t c;
 529
 530                         /* from xbee to cmdline */
 531                         c = xbee_dev_recv(NULL);
 532                         if (c >= 0)
 533                                 cmdline_dev_send((uint8_t)c, NULL);
 534
 535                         /* from cmdline to xbee */
 536                         c = cmdline_dev_recv(NULL);
 537                         if (c == 4) { /* CTRL-d */
 538                                 xbee_raw = 0;
 539                                 rdline_newline(&xbeeboard.rdl,
 540                                                xbeeboard.prompt);
 541                         }
 542                         else if (c >= 0) {
 543                                 /* send to xbee */
 544                                 xbee_dev_send((uint8_t)c, NULL);
 545
 546                                 /* echo on cmdline */
 547                                 cmdline_dev_send((uint8_t)c, NULL);
 548                         }
 549                 }
 550                 else {
 551                         if (xbee_cmdline_input_enabled)
 552                                 cmdline_poll();
 553                         xbee_proto_rx(xbee_dev);
 554                 }
 555
 556 #ifdef USE_USB
 557                 CDC_Device_USBTask(&VirtualSerial1_CDC_Interface);
 558                 CDC_Device_USBTask(&VirtualSerial2_CDC_Interface);
 559                 USB_USBTask();
 560 #endif
 561         }
 562 }
 563
 564 /* return time in milliseconds on unsigned 16 bits */
 565 static uint16_t get_time_ms(void)
 566 {
 567         return global_ms;
 568 }
 569
 570 static void do_led_blink(struct callout_manager *cm,
 571                          struct callout *clt, void *dummy)
 572 {
 573         static uint8_t a = 0;
 574
 575 #ifdef USE_USB
 576         if (a & 1)
 577                 LEDs_SetAllLEDs(0);
 578         else
 579                 LEDs_SetAllLEDs(0xff);
 580 #else
 581         /* XXX */
 582 #endif
 583         a++;
 584 }
 585
 586 static void increment_ms(void *dummy)
 587 {
 588         global_ms++;
 589 }
 590
 591 static void main_timer_interrupt(void)
 592 {
 593         static uint8_t cpt = 0;
 594         cpt++;
 595         sei();
 596         if ((cpt & 0x3) == 0)
 597                 scheduler_interrupt();
 598 }
 599
 600 /** Main program entry point. This routine contains the overall program flow, including initial
 601  *  setup of all components and the main program loop.
 602  */
 603 int main(void)
 604 {
 605         struct callout t1;
 606         FILE *xbee_file;
 607         int8_t err;
 608         struct xbee_dev dev;
 609
 610 #ifdef USE_USB
 611         SetupHardware();
 612
 613         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 614 #else
 615         uart_init();
 616 #endif
 617
 618         fdevopen(cmdline_dev_send, cmdline_dev_recv);
 619         xbee_file = fdevopen(xbee_dev_send, xbee_dev_recv);
 620         scheduler_init();
 621         timer_init();
 622         timer0_register_OV_intr(main_timer_interrupt);
 623
 624         scheduler_add_periodical_event_priority(increment_ms, NULL,
 625                                                 1000L / SCHEDULER_UNIT,
 626                                                 LED_PRIO);
 627         cmdline_init();
 628 #ifndef USE_USB
 629         /* in usb mode, it's done in usb callback */
 630         rdline_newline(&xbeeboard.rdl, xbeeboard.prompt);
 631 #endif
 632         callout_manager_init(&cm, get_time_ms);
 633         callout_reset(&cm, &t1, 500, PERIODICAL, do_led_blink, NULL);
 634
 635         /* initialize libxbee */
 636         err = xbee_init();
 637         if (err < 0)
 638                 return -1;
 639
 640         xbee_dev = &dev;
 641
 642         /* open xbee device */
 643         if (xbee_open(xbee_dev, xbee_file) < 0)
 644                 return -1;
 645
 646         /* register default channel with a callback */
 647         if (xbee_register_channel(xbee_dev, XBEE_DEFAULT_CHANNEL,
 648                                   xbee_rx, NULL) < 0) {
 649                 fprintf(stderr, "cannot register default channel\n");
 650                 return -1;
 651         }
 652
 653         sei();
 654         xbee_mainloop();
 655         return 0;
 656 }