/* * slip.c * ------ * SLIP send/recv code, based on RFC 1055 * * Copyright (c) 2016, NORDUnet A/S All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * - Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of the NORDUnet nor the names of its contributors may * be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include /* perror */ #include "slip_internal.h" /* SLIP special character codes */ #define END 0300 /* indicates end of packet */ #define ESC 0333 /* indicates byte stuffing */ #define ESC_END 0334 /* ESC ESC_END means END data byte */ #define ESC_ESC 0335 /* ESC ESC_ESC means ESC data byte */ #define check_send_char(c) \ if (hal_serial_send_char(c) != HAL_OK) \ return perror("hal_serial_send_char"), HAL_ERROR_RPC_TRANSPORT; /* Send a single character with SLIP escaping. */ hal_error_t hal_slip_send_char(const uint8_t c) { switch (c) { case END: check_send_char(ESC); check_send_char(ESC_END); break; case ESC: check_send_char(ESC); check_send_char(ESC_ESC); break; default: check_send_char(c); } return HAL_OK; } /* Send a message with SLIP framing. */ hal_error_t hal_slip_send(const uint8_t * const buf, const size_t len) { /* send an initial END character to flush out any data that may * have accumulated in the receiver due to line noise */ check_send_char(END); /* for each byte in the packet, send the appropriate character * sequence */ for (int i = 0; i < len; ++i) { hal_error_t ret; if ((ret = hal_slip_send_char(buf[i])) != HAL_OK) return ret; } /* tell the receiver that we're done sending the packet */ check_send_char(END); return HAL_OK; } #define check_recv_char(c) \ if (hal_serial_recv_char(c) != HAL_OK) \ return perror("hal_serial_recv_char"), HAL_ERROR_RPC_TRANSPORT; /* Receive a single character into a buffer, with SLIP un-escaping */ hal_error_t hal_slip_recv_char(uint8_t * const buf, size_t * const len, const size_t maxlen, int * const complete) { #define buf_push(c) do { if (*len < maxlen) buf[(*len)++] = c; } while (0) static int esc_flag = 0; uint8_t c; hal_error_t ret = hal_serial_recv_char(&c); if (ret != HAL_OK) return perror("hal_slip_recv_char"), ret; *complete = 0; switch (c) { case END: if (*len) *complete = 1; break; case ESC: esc_flag = 1; break; default: if (esc_flag) { esc_flag = 0; switch (c) { case ESC_END: buf_push(END); break; case ESC_ESC: buf_push(ESC); break; default: buf_push(c); } } else { buf_push(c); } break; } return HAL_OK; } /* Receive a message with SLIP framing, blocking mode. */ hal_error_t hal_slip_recv(uint8_t * const buf, size_t * const len, const size_t maxlen) { int complete; hal_error_t ret; while (1) { ret = hal_slip_recv_char(buf, len, maxlen, &complete); if ((ret != HAL_OK) || complete) return ret; } } >39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109