1 | #ifndef _MAVLINK_HELPERS_H_
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2 | #define _MAVLINK_HELPERS_H_
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3 |
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4 | #include "string.h"
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5 | #include "checksum.h"
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6 | #include "mavlink_types.h"
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7 | #include "mavlink_conversions.h"
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8 | #include <stdio.h>
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9 |
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10 | #ifndef MAVLINK_HELPER
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11 | #define MAVLINK_HELPER
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12 | #endif
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13 |
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14 | #include "mavlink_sha256.h"
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15 |
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16 | /*
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17 | * Internal function to give access to the channel status for each channel
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18 | */
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19 | #ifndef MAVLINK_GET_CHANNEL_STATUS
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20 | MAVLINK_HELPER mavlink_status_t* mavlink_get_channel_status(uint8_t chan)
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21 | {
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22 | #ifdef MAVLINK_EXTERNAL_RX_STATUS
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23 | // No m_mavlink_status array defined in function,
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24 | // has to be defined externally
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25 | #else
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26 | static mavlink_status_t m_mavlink_status[MAVLINK_COMM_NUM_BUFFERS];
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27 | #endif
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28 | return &m_mavlink_status[chan];
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29 | }
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30 | #endif
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31 |
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32 | /*
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33 | * Internal function to give access to the channel buffer for each channel
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34 | */
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35 | #ifndef MAVLINK_GET_CHANNEL_BUFFER
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36 | MAVLINK_HELPER mavlink_message_t* mavlink_get_channel_buffer(uint8_t chan)
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37 | {
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38 |
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39 | #ifdef MAVLINK_EXTERNAL_RX_BUFFER
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40 | // No m_mavlink_buffer array defined in function,
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41 | // has to be defined externally
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42 | #else
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43 | static mavlink_message_t m_mavlink_buffer[MAVLINK_COMM_NUM_BUFFERS];
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44 | #endif
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45 | return &m_mavlink_buffer[chan];
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46 | }
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47 | #endif // MAVLINK_GET_CHANNEL_BUFFER
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48 |
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49 | /**
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50 | * @brief Reset the status of a channel.
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51 | */
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52 | MAVLINK_HELPER void mavlink_reset_channel_status(uint8_t chan)
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53 | {
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54 | mavlink_status_t *status = mavlink_get_channel_status(chan);
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55 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
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56 | }
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57 |
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58 | /**
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59 | * @brief create a signature block for a packet
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60 | */
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61 | MAVLINK_HELPER uint8_t mavlink_sign_packet(mavlink_signing_t *signing,
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62 | uint8_t signature[MAVLINK_SIGNATURE_BLOCK_LEN],
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63 | const uint8_t *header, uint8_t header_len,
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64 | const uint8_t *packet, uint8_t packet_len,
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65 | const uint8_t crc[2])
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66 | {
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67 | mavlink_sha256_ctx ctx;
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68 | union {
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69 | uint64_t t64;
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70 | uint8_t t8[8];
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71 | } tstamp;
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72 | if (signing == NULL || !(signing->flags & MAVLINK_SIGNING_FLAG_SIGN_OUTGOING)) {
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73 | return 0;
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74 | }
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75 | signature[0] = signing->link_id;
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76 | tstamp.t64 = signing->timestamp;
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77 | memcpy(&signature[1], tstamp.t8, 6);
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78 | signing->timestamp++;
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79 |
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80 | mavlink_sha256_init(&ctx);
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81 | mavlink_sha256_update(&ctx, signing->secret_key, sizeof(signing->secret_key));
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82 | mavlink_sha256_update(&ctx, header, header_len);
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83 | mavlink_sha256_update(&ctx, packet, packet_len);
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84 | mavlink_sha256_update(&ctx, crc, 2);
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85 | mavlink_sha256_update(&ctx, signature, 7);
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86 | mavlink_sha256_final_48(&ctx, &signature[7]);
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87 |
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88 | return MAVLINK_SIGNATURE_BLOCK_LEN;
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89 | }
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90 |
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91 | /**
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92 | * return new packet length for trimming payload of any trailing zero
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93 | * bytes. Used in MAVLink2 to give simple support for variable length
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94 | * arrays.
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95 | */
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96 | MAVLINK_HELPER uint8_t _mav_trim_payload(const char *payload, uint8_t length)
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97 | {
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98 | while (length > 0 && payload[length-1] == 0) {
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99 | length--;
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100 | }
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101 | return length;
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102 | }
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103 |
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104 | /**
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105 | * @brief check a signature block for a packet
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106 | */
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107 | MAVLINK_HELPER bool mavlink_signature_check(mavlink_signing_t *signing,
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108 | mavlink_signing_streams_t *signing_streams,
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109 | const mavlink_message_t *msg)
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110 | {
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111 | if (signing == NULL) {
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112 | return true;
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113 | }
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114 | const uint8_t *p = (const uint8_t *)&msg->magic;
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115 | const uint8_t *psig = msg->signature;
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116 | const uint8_t *incoming_signature = psig+7;
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117 | mavlink_sha256_ctx ctx;
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118 | uint8_t signature[6];
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119 | uint16_t i;
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120 |
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121 | mavlink_sha256_init(&ctx);
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122 | mavlink_sha256_update(&ctx, signing->secret_key, sizeof(signing->secret_key));
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123 | mavlink_sha256_update(&ctx, p, MAVLINK_CORE_HEADER_LEN+1+msg->len);
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124 | mavlink_sha256_update(&ctx, msg->ck, 2);
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125 | mavlink_sha256_update(&ctx, psig, 1+6);
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126 | mavlink_sha256_final_48(&ctx, signature);
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127 | if (memcmp(signature, incoming_signature, 6) != 0) {
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128 | return false;
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129 | }
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130 |
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131 | // now check timestamp
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132 | union tstamp {
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133 | uint64_t t64;
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134 | uint8_t t8[8];
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135 | } tstamp;
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136 | uint8_t link_id = psig[0];
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137 | tstamp.t64 = 0;
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138 | memcpy(tstamp.t8, psig+1, 6);
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139 |
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140 | if (signing_streams == NULL) {
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141 | return false;
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142 | }
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143 |
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144 | // find stream
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145 | for (i=0; i<signing_streams->num_signing_streams; i++) {
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146 | if (msg->sysid == signing_streams->stream[i].sysid &&
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147 | msg->compid == signing_streams->stream[i].compid &&
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148 | link_id == signing_streams->stream[i].link_id) {
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149 | break;
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150 | }
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151 | }
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152 | if (i == signing_streams->num_signing_streams) {
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153 | if (signing_streams->num_signing_streams >= MAVLINK_MAX_SIGNING_STREAMS) {
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154 | // over max number of streams
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155 | return false;
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156 | }
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157 | // new stream. Only accept if timestamp is not more than 1 minute old
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158 | if (tstamp.t64 + 6000*1000UL < signing->timestamp) {
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159 | return false;
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160 | }
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161 | // add new stream
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162 | signing_streams->stream[i].sysid = msg->sysid;
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163 | signing_streams->stream[i].compid = msg->compid;
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164 | signing_streams->stream[i].link_id = link_id;
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165 | signing_streams->num_signing_streams++;
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166 | } else {
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167 | union tstamp last_tstamp;
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168 | last_tstamp.t64 = 0;
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169 | memcpy(last_tstamp.t8, signing_streams->stream[i].timestamp_bytes, 6);
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170 | if (tstamp.t64 <= last_tstamp.t64) {
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171 | // repeating old timestamp
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172 | return false;
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173 | }
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174 | }
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175 |
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176 | // remember last timestamp
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177 | memcpy(signing_streams->stream[i].timestamp_bytes, psig+1, 6);
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178 |
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179 | // our next timestamp must be at least this timestamp
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180 | if (tstamp.t64 > signing->timestamp) {
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181 | signing->timestamp = tstamp.t64;
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182 | }
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183 | return true;
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184 | }
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185 |
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186 |
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187 | /**
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188 | * @brief Finalize a MAVLink message with channel assignment
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189 | *
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190 | * This function calculates the checksum and sets length and aircraft id correctly.
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191 | * It assumes that the message id and the payload are already correctly set. This function
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192 | * can also be used if the message header has already been written before (as in mavlink_msg_xxx_pack
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193 | * instead of mavlink_msg_xxx_pack_headerless), it just introduces little extra overhead.
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194 | *
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195 | * @param msg Message to finalize
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196 | * @param system_id Id of the sending (this) system, 1-127
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197 | * @param length Message length
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198 | */
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199 | MAVLINK_HELPER uint16_t mavlink_finalize_message_chan(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id,
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200 | uint8_t chan, uint8_t min_length, uint8_t length, uint8_t crc_extra)
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201 | {
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202 | mavlink_status_t *status = mavlink_get_channel_status(chan);
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203 | bool mavlink1 = (status->flags & MAVLINK_STATUS_FLAG_OUT_MAVLINK1) != 0;
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204 | bool signing = (!mavlink1) && status->signing && (status->signing->flags & MAVLINK_SIGNING_FLAG_SIGN_OUTGOING);
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205 | uint8_t signature_len = signing? MAVLINK_SIGNATURE_BLOCK_LEN : 0;
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206 | uint8_t header_len = MAVLINK_CORE_HEADER_LEN+1;
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207 | uint8_t buf[MAVLINK_CORE_HEADER_LEN+1];
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208 | if (mavlink1) {
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209 | msg->magic = MAVLINK_STX_MAVLINK1;
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210 | header_len = MAVLINK_CORE_HEADER_MAVLINK1_LEN+1;
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211 | } else {
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212 | msg->magic = MAVLINK_STX;
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213 | }
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214 | msg->len = mavlink1?min_length:_mav_trim_payload(_MAV_PAYLOAD(msg), length);
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215 | msg->sysid = system_id;
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216 | msg->compid = component_id;
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217 | msg->incompat_flags = 0;
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218 | if (signing) {
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219 | msg->incompat_flags |= MAVLINK_IFLAG_SIGNED;
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220 | }
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221 | msg->compat_flags = 0;
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222 | msg->seq = status->current_tx_seq;
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223 | status->current_tx_seq = status->current_tx_seq + 1;
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224 |
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225 | // form the header as a byte array for the crc
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226 | buf[0] = msg->magic;
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227 | buf[1] = msg->len;
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228 | if (mavlink1) {
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229 | buf[2] = msg->seq;
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230 | buf[3] = msg->sysid;
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231 | buf[4] = msg->compid;
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232 | buf[5] = msg->msgid & 0xFF;
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233 | } else {
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234 | buf[2] = msg->incompat_flags;
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235 | buf[3] = msg->compat_flags;
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236 | buf[4] = msg->seq;
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237 | buf[5] = msg->sysid;
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238 | buf[6] = msg->compid;
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239 | buf[7] = msg->msgid & 0xFF;
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240 | buf[8] = (msg->msgid >> 8) & 0xFF;
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241 | buf[9] = (msg->msgid >> 16) & 0xFF;
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242 | }
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243 |
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244 | msg->checksum = crc_calculate(&buf[1], header_len-1);
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245 | crc_accumulate_buffer(&msg->checksum, _MAV_PAYLOAD(msg), msg->len);
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246 | crc_accumulate(crc_extra, &msg->checksum);
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247 | mavlink_ck_a(msg) = (uint8_t)(msg->checksum & 0xFF);
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248 | mavlink_ck_b(msg) = (uint8_t)(msg->checksum >> 8);
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249 |
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250 | if (signing) {
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251 | mavlink_sign_packet(status->signing,
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252 | msg->signature,
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253 | (const uint8_t *)buf, header_len,
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254 | (const uint8_t *)_MAV_PAYLOAD(msg), msg->len,
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255 | (const uint8_t *)_MAV_PAYLOAD(msg)+(uint16_t)msg->len);
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256 | }
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257 |
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258 | return msg->len + header_len + 2 + signature_len;
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259 | }
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260 |
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261 |
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262 | /**
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263 | * @brief Finalize a MAVLink message with MAVLINK_COMM_0 as default channel
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264 | */
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265 | MAVLINK_HELPER uint16_t mavlink_finalize_message(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id,
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266 | uint8_t min_length, uint8_t length, uint8_t crc_extra)
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267 | {
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268 | return mavlink_finalize_message_chan(msg, system_id, component_id, MAVLINK_COMM_0, min_length, length, crc_extra);
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269 | }
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270 |
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271 | static inline void _mav_parse_error(mavlink_status_t *status)
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272 | {
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273 | status->parse_error++;
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274 | }
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275 |
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276 | #ifdef MAVLINK_USE_CONVENIENCE_FUNCTIONS
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277 | MAVLINK_HELPER void _mavlink_send_uart(mavlink_channel_t chan, const char *buf, uint16_t len);
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278 |
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279 | /**
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280 | * @brief Finalize a MAVLink message with channel assignment and send
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281 | */
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282 | MAVLINK_HELPER void _mav_finalize_message_chan_send(mavlink_channel_t chan, uint32_t msgid,
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283 | const char *packet,
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284 | uint8_t min_length, uint8_t length, uint8_t crc_extra)
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285 | {
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286 | uint16_t checksum;
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287 | uint8_t buf[MAVLINK_NUM_HEADER_BYTES];
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288 | uint8_t ck[2];
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289 | mavlink_status_t *status = mavlink_get_channel_status(chan);
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290 | uint8_t header_len = MAVLINK_CORE_HEADER_LEN;
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291 | uint8_t signature_len = 0;
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292 | uint8_t signature[MAVLINK_SIGNATURE_BLOCK_LEN];
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293 | bool mavlink1 = (status->flags & MAVLINK_STATUS_FLAG_OUT_MAVLINK1) != 0;
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294 | bool signing = (!mavlink1) && status->signing && (status->signing->flags & MAVLINK_SIGNING_FLAG_SIGN_OUTGOING);
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295 |
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296 | if (mavlink1) {
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297 | length = min_length;
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298 | if (msgid > 255) {
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299 | // can't send 16 bit messages
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300 | _mav_parse_error(status);
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301 | return;
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302 | }
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303 | header_len = MAVLINK_CORE_HEADER_MAVLINK1_LEN;
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304 | buf[0] = MAVLINK_STX_MAVLINK1;
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305 | buf[1] = length;
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306 | buf[2] = status->current_tx_seq;
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307 | buf[3] = mavlink_system.sysid;
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308 | buf[4] = mavlink_system.compid;
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309 | buf[5] = msgid & 0xFF;
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310 | } else {
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311 | uint8_t incompat_flags = 0;
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312 | if (signing) {
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313 | incompat_flags |= MAVLINK_IFLAG_SIGNED;
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314 | }
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315 | length = _mav_trim_payload(packet, length);
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316 | buf[0] = MAVLINK_STX;
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317 | buf[1] = length;
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318 | buf[2] = incompat_flags;
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319 | buf[3] = 0; // compat_flags
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320 | buf[4] = status->current_tx_seq;
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321 | buf[5] = mavlink_system.sysid;
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322 | buf[6] = mavlink_system.compid;
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323 | buf[7] = msgid & 0xFF;
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324 | buf[8] = (msgid >> 8) & 0xFF;
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325 | buf[9] = (msgid >> 16) & 0xFF;
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326 | }
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327 | status->current_tx_seq++;
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328 | checksum = crc_calculate((const uint8_t*)&buf[1], header_len);
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329 | crc_accumulate_buffer(&checksum, packet, length);
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330 | crc_accumulate(crc_extra, &checksum);
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331 | ck[0] = (uint8_t)(checksum & 0xFF);
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332 | ck[1] = (uint8_t)(checksum >> 8);
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333 |
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334 | if (signing) {
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335 | // possibly add a signature
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336 | signature_len = mavlink_sign_packet(status->signing, signature, buf, header_len+1,
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337 | (const uint8_t *)packet, length, ck);
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338 | }
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339 |
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340 | MAVLINK_START_UART_SEND(chan, header_len + 3 + (uint16_t)length + (uint16_t)signature_len);
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341 | _mavlink_send_uart(chan, (const char *)buf, header_len+1);
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342 | _mavlink_send_uart(chan, packet, length);
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343 | _mavlink_send_uart(chan, (const char *)ck, 2);
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344 | if (signature_len != 0) {
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345 | _mavlink_send_uart(chan, (const char *)signature, signature_len);
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346 | }
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347 | MAVLINK_END_UART_SEND(chan, header_len + 3 + (uint16_t)length + (uint16_t)signature_len);
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348 | }
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349 |
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350 | /**
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351 | * @brief re-send a message over a uart channel
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352 | * this is more stack efficient than re-marshalling the message
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353 | * If the message is signed then the original signature is also sent
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354 | */
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355 | MAVLINK_HELPER void _mavlink_resend_uart(mavlink_channel_t chan, const mavlink_message_t *msg)
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356 | {
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357 | uint8_t ck[2];
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358 |
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359 | ck[0] = (uint8_t)(msg->checksum & 0xFF);
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360 | ck[1] = (uint8_t)(msg->checksum >> 8);
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361 | // XXX use the right sequence here
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362 |
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363 | uint8_t header_len;
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364 | uint8_t signature_len;
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365 |
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366 | if (msg->magic == MAVLINK_STX_MAVLINK1) {
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367 | header_len = MAVLINK_CORE_HEADER_MAVLINK1_LEN + 1;
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368 | signature_len = 0;
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369 | MAVLINK_START_UART_SEND(chan, header_len + msg->len + 2 + signature_len);
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370 | // we can't send the structure directly as it has extra mavlink2 elements in it
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371 | uint8_t buf[header_len];
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372 | buf[0] = msg->magic;
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373 | buf[1] = msg->len;
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374 | buf[2] = msg->seq;
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375 | buf[3] = msg->sysid;
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376 | buf[4] = msg->compid;
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377 | buf[5] = msg->msgid & 0xFF;
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378 | _mavlink_send_uart(chan, (const char*)buf, header_len);
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379 | } else {
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380 | header_len = MAVLINK_CORE_HEADER_LEN + 1;
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381 | signature_len = (msg->incompat_flags & MAVLINK_IFLAG_SIGNED)?MAVLINK_SIGNATURE_BLOCK_LEN:0;
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382 | MAVLINK_START_UART_SEND(chan, header_len + msg->len + 2 + signature_len);
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383 | uint8_t buf[header_len];
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384 | buf[0] = msg->magic;
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385 | buf[1] = msg->len;
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386 | buf[2] = msg->incompat_flags;
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387 | buf[3] = msg->compat_flags;
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388 | buf[4] = msg->seq;
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389 | buf[5] = msg->sysid;
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390 | buf[6] = msg->compid;
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391 | buf[7] = msg->msgid & 0xFF;
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392 | buf[8] = (msg->msgid >> 8) & 0xFF;
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393 | buf[9] = (msg->msgid >> 16) & 0xFF;
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394 | _mavlink_send_uart(chan, (const char *)buf, header_len);
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395 | }
|
---|
396 | _mavlink_send_uart(chan, _MAV_PAYLOAD(msg), msg->len);
|
---|
397 | _mavlink_send_uart(chan, (const char *)ck, 2);
|
---|
398 | if (signature_len != 0) {
|
---|
399 | _mavlink_send_uart(chan, (const char *)msg->signature, MAVLINK_SIGNATURE_BLOCK_LEN);
|
---|
400 | }
|
---|
401 | MAVLINK_END_UART_SEND(chan, header_len + msg->len + 2 + signature_len);
|
---|
402 | }
|
---|
403 | #endif // MAVLINK_USE_CONVENIENCE_FUNCTIONS
|
---|
404 |
|
---|
405 | /**
|
---|
406 | * @brief Pack a message to send it over a serial byte stream
|
---|
407 | */
|
---|
408 | MAVLINK_HELPER uint16_t mavlink_msg_to_send_buffer(uint8_t *buf, const mavlink_message_t *msg)
|
---|
409 | {
|
---|
410 | uint8_t signature_len, header_len;
|
---|
411 | uint8_t *ck;
|
---|
412 | uint8_t length = msg->len;
|
---|
413 |
|
---|
414 | if (msg->magic == MAVLINK_STX_MAVLINK1) {
|
---|
415 | signature_len = 0;
|
---|
416 | header_len = MAVLINK_CORE_HEADER_MAVLINK1_LEN;
|
---|
417 | buf[0] = msg->magic;
|
---|
418 | buf[1] = length;
|
---|
419 | buf[2] = msg->seq;
|
---|
420 | buf[3] = msg->sysid;
|
---|
421 | buf[4] = msg->compid;
|
---|
422 | buf[5] = msg->msgid & 0xFF;
|
---|
423 | memcpy(&buf[6], _MAV_PAYLOAD(msg), msg->len);
|
---|
424 | ck = buf + header_len + 1 + (uint16_t)msg->len;
|
---|
425 | } else {
|
---|
426 | length = _mav_trim_payload(_MAV_PAYLOAD(msg), length);
|
---|
427 | header_len = MAVLINK_CORE_HEADER_LEN;
|
---|
428 | buf[0] = msg->magic;
|
---|
429 | buf[1] = length;
|
---|
430 | buf[2] = msg->incompat_flags;
|
---|
431 | buf[3] = msg->compat_flags;
|
---|
432 | buf[4] = msg->seq;
|
---|
433 | buf[5] = msg->sysid;
|
---|
434 | buf[6] = msg->compid;
|
---|
435 | buf[7] = msg->msgid & 0xFF;
|
---|
436 | buf[8] = (msg->msgid >> 8) & 0xFF;
|
---|
437 | buf[9] = (msg->msgid >> 16) & 0xFF;
|
---|
438 | memcpy(&buf[10], _MAV_PAYLOAD(msg), length);
|
---|
439 | ck = buf + header_len + 1 + (uint16_t)length;
|
---|
440 | signature_len = (msg->incompat_flags & MAVLINK_IFLAG_SIGNED)?MAVLINK_SIGNATURE_BLOCK_LEN:0;
|
---|
441 | }
|
---|
442 | ck[0] = (uint8_t)(msg->checksum & 0xFF);
|
---|
443 | ck[1] = (uint8_t)(msg->checksum >> 8);
|
---|
444 | if (signature_len > 0) {
|
---|
445 | memcpy(&ck[2], msg->signature, signature_len);
|
---|
446 | }
|
---|
447 |
|
---|
448 | return header_len + 1 + 2 + (uint16_t)length + (uint16_t)signature_len;
|
---|
449 | }
|
---|
450 |
|
---|
451 | union __mavlink_bitfield {
|
---|
452 | uint8_t uint8;
|
---|
453 | int8_t int8;
|
---|
454 | uint16_t uint16;
|
---|
455 | int16_t int16;
|
---|
456 | uint32_t uint32;
|
---|
457 | int32_t int32;
|
---|
458 | };
|
---|
459 |
|
---|
460 |
|
---|
461 | MAVLINK_HELPER void mavlink_start_checksum(mavlink_message_t* msg)
|
---|
462 | {
|
---|
463 | crc_init(&msg->checksum);
|
---|
464 | }
|
---|
465 |
|
---|
466 | MAVLINK_HELPER void mavlink_update_checksum(mavlink_message_t* msg, uint8_t c)
|
---|
467 | {
|
---|
468 | crc_accumulate(c, &msg->checksum);
|
---|
469 | }
|
---|
470 |
|
---|
471 | /*
|
---|
472 | return the crc_entry value for a msgid
|
---|
473 | */
|
---|
474 | MAVLINK_HELPER const mavlink_msg_entry_t *mavlink_get_msg_entry(uint32_t msgid)
|
---|
475 | {
|
---|
476 | static const mavlink_msg_entry_t mavlink_message_crcs[] = MAVLINK_MESSAGE_CRCS;
|
---|
477 | /*
|
---|
478 | use a bisection search to find the right entry. A perfect hash may be better
|
---|
479 | Note that this assumes the table is sorted by msgid
|
---|
480 | */
|
---|
481 | uint32_t low=0, high=sizeof(mavlink_message_crcs)/sizeof(mavlink_message_crcs[0]);
|
---|
482 | while (low < high) {
|
---|
483 | uint32_t mid = (low+1+high)/2;
|
---|
484 | if (msgid < mavlink_message_crcs[mid].msgid) {
|
---|
485 | high = mid-1;
|
---|
486 | continue;
|
---|
487 | }
|
---|
488 | if (msgid > mavlink_message_crcs[mid].msgid) {
|
---|
489 | low = mid;
|
---|
490 | continue;
|
---|
491 | }
|
---|
492 | low = mid;
|
---|
493 | break;
|
---|
494 | }
|
---|
495 | if (mavlink_message_crcs[low].msgid != msgid) {
|
---|
496 | // msgid is not in the table
|
---|
497 | return NULL;
|
---|
498 | }
|
---|
499 | return &mavlink_message_crcs[low];
|
---|
500 | }
|
---|
501 |
|
---|
502 | /*
|
---|
503 | return the crc_extra value for a message
|
---|
504 | */
|
---|
505 | MAVLINK_HELPER uint8_t mavlink_get_crc_extra(const mavlink_message_t *msg)
|
---|
506 | {
|
---|
507 | const mavlink_msg_entry_t *e = mavlink_get_msg_entry(msg->msgid);
|
---|
508 | return e?e->crc_extra:0;
|
---|
509 | }
|
---|
510 |
|
---|
511 | /*
|
---|
512 | return the expected message length
|
---|
513 | */
|
---|
514 | #define MAVLINK_HAVE_EXPECTED_MESSAGE_LENGTH
|
---|
515 | MAVLINK_HELPER uint8_t mavlink_expected_message_length(const mavlink_message_t *msg)
|
---|
516 | {
|
---|
517 | const mavlink_msg_entry_t *e = mavlink_get_msg_entry(msg->msgid);
|
---|
518 | return e?e->msg_len:0;
|
---|
519 | }
|
---|
520 |
|
---|
521 | /**
|
---|
522 | * This is a varient of mavlink_frame_char() but with caller supplied
|
---|
523 | * parsing buffers. It is useful when you want to create a MAVLink
|
---|
524 | * parser in a library that doesn't use any global variables
|
---|
525 | *
|
---|
526 | * @param rxmsg parsing message buffer
|
---|
527 | * @param status parsing starus buffer
|
---|
528 | * @param c The char to parse
|
---|
529 | *
|
---|
530 | * @param returnMsg NULL if no message could be decoded, the message data else
|
---|
531 | * @param returnStats if a message was decoded, this is filled with the channel's stats
|
---|
532 | * @return 0 if no message could be decoded, 1 on good message and CRC, 2 on bad CRC
|
---|
533 | *
|
---|
534 | * A typical use scenario of this function call is:
|
---|
535 | *
|
---|
536 | * @code
|
---|
537 | * #include <mavlink.h>
|
---|
538 | *
|
---|
539 | * mavlink_message_t msg;
|
---|
540 | * int chan = 0;
|
---|
541 | *
|
---|
542 | *
|
---|
543 | * while(serial.bytesAvailable > 0)
|
---|
544 | * {
|
---|
545 | * uint8_t byte = serial.getNextByte();
|
---|
546 | * if (mavlink_frame_char(chan, byte, &msg) != MAVLINK_FRAMING_INCOMPLETE)
|
---|
547 | * {
|
---|
548 | * printf("Received message with ID %d, sequence: %d from component %d of system %d", msg.msgid, msg.seq, msg.compid, msg.sysid);
|
---|
549 | * }
|
---|
550 | * }
|
---|
551 | *
|
---|
552 | *
|
---|
553 | * @endcode
|
---|
554 | */
|
---|
555 | MAVLINK_HELPER uint8_t mavlink_frame_char_buffer(mavlink_message_t* rxmsg,
|
---|
556 | mavlink_status_t* status,
|
---|
557 | uint8_t c,
|
---|
558 | mavlink_message_t* r_message,
|
---|
559 | mavlink_status_t* r_mavlink_status)
|
---|
560 | {
|
---|
561 | /* Enable this option to check the length of each message.
|
---|
562 | This allows invalid messages to be caught much sooner. Use if the transmission
|
---|
563 | medium is prone to missing (or extra) characters (e.g. a radio that fades in
|
---|
564 | and out). Only use if the channel will only contain messages types listed in
|
---|
565 | the headers.
|
---|
566 | */
|
---|
567 | #ifdef MAVLINK_CHECK_MESSAGE_LENGTH
|
---|
568 | #ifndef MAVLINK_MESSAGE_LENGTH
|
---|
569 | static const uint8_t mavlink_message_lengths[256] = MAVLINK_MESSAGE_LENGTHS;
|
---|
570 | #define MAVLINK_MESSAGE_LENGTH(msgid) mavlink_message_lengths[msgid]
|
---|
571 | #endif
|
---|
572 | #endif
|
---|
573 |
|
---|
574 | int bufferIndex = 0;
|
---|
575 |
|
---|
576 | status->msg_received = MAVLINK_FRAMING_INCOMPLETE;
|
---|
577 |
|
---|
578 | switch (status->parse_state)
|
---|
579 | {
|
---|
580 | case MAVLINK_PARSE_STATE_UNINIT:
|
---|
581 | case MAVLINK_PARSE_STATE_IDLE:
|
---|
582 | if (c == MAVLINK_STX)
|
---|
583 | {
|
---|
584 | status->parse_state = MAVLINK_PARSE_STATE_GOT_STX;
|
---|
585 | rxmsg->len = 0;
|
---|
586 | rxmsg->magic = c;
|
---|
587 | status->flags &= ~MAVLINK_STATUS_FLAG_IN_MAVLINK1;
|
---|
588 | mavlink_start_checksum(rxmsg);
|
---|
589 | } else if (c == MAVLINK_STX_MAVLINK1)
|
---|
590 | {
|
---|
591 | status->parse_state = MAVLINK_PARSE_STATE_GOT_STX;
|
---|
592 | rxmsg->len = 0;
|
---|
593 | rxmsg->magic = c;
|
---|
594 | status->flags |= MAVLINK_STATUS_FLAG_IN_MAVLINK1;
|
---|
595 | mavlink_start_checksum(rxmsg);
|
---|
596 | }
|
---|
597 | break;
|
---|
598 |
|
---|
599 | case MAVLINK_PARSE_STATE_GOT_STX:
|
---|
600 | if (status->msg_received
|
---|
601 | /* Support shorter buffers than the
|
---|
602 | default maximum packet size */
|
---|
603 | #if (MAVLINK_MAX_PAYLOAD_LEN < 255)
|
---|
604 | || c > MAVLINK_MAX_PAYLOAD_LEN
|
---|
605 | #endif
|
---|
606 | )
|
---|
607 | {
|
---|
608 | status->buffer_overrun++;
|
---|
609 | _mav_parse_error(status);
|
---|
610 | status->msg_received = 0;
|
---|
611 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
612 | }
|
---|
613 | else
|
---|
614 | {
|
---|
615 | // NOT counting STX, LENGTH, SEQ, SYSID, COMPID, MSGID, CRC1 and CRC2
|
---|
616 | rxmsg->len = c;
|
---|
617 | status->packet_idx = 0;
|
---|
618 | mavlink_update_checksum(rxmsg, c);
|
---|
619 | if (status->flags & MAVLINK_STATUS_FLAG_IN_MAVLINK1) {
|
---|
620 | rxmsg->incompat_flags = 0;
|
---|
621 | rxmsg->compat_flags = 0;
|
---|
622 | status->parse_state = MAVLINK_PARSE_STATE_GOT_COMPAT_FLAGS;
|
---|
623 | } else {
|
---|
624 | status->parse_state = MAVLINK_PARSE_STATE_GOT_LENGTH;
|
---|
625 | }
|
---|
626 | }
|
---|
627 | break;
|
---|
628 |
|
---|
629 | case MAVLINK_PARSE_STATE_GOT_LENGTH:
|
---|
630 | rxmsg->incompat_flags = c;
|
---|
631 | if ((rxmsg->incompat_flags & ~MAVLINK_IFLAG_MASK) != 0) {
|
---|
632 | // message includes an incompatible feature flag
|
---|
633 | _mav_parse_error(status);
|
---|
634 | status->msg_received = 0;
|
---|
635 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
636 | break;
|
---|
637 | }
|
---|
638 | mavlink_update_checksum(rxmsg, c);
|
---|
639 | status->parse_state = MAVLINK_PARSE_STATE_GOT_INCOMPAT_FLAGS;
|
---|
640 | break;
|
---|
641 |
|
---|
642 | case MAVLINK_PARSE_STATE_GOT_INCOMPAT_FLAGS:
|
---|
643 | rxmsg->compat_flags = c;
|
---|
644 | mavlink_update_checksum(rxmsg, c);
|
---|
645 | status->parse_state = MAVLINK_PARSE_STATE_GOT_COMPAT_FLAGS;
|
---|
646 | break;
|
---|
647 |
|
---|
648 | case MAVLINK_PARSE_STATE_GOT_COMPAT_FLAGS:
|
---|
649 | rxmsg->seq = c;
|
---|
650 | mavlink_update_checksum(rxmsg, c);
|
---|
651 | status->parse_state = MAVLINK_PARSE_STATE_GOT_SEQ;
|
---|
652 | break;
|
---|
653 |
|
---|
654 | case MAVLINK_PARSE_STATE_GOT_SEQ:
|
---|
655 | rxmsg->sysid = c;
|
---|
656 | mavlink_update_checksum(rxmsg, c);
|
---|
657 | status->parse_state = MAVLINK_PARSE_STATE_GOT_SYSID;
|
---|
658 | break;
|
---|
659 |
|
---|
660 | case MAVLINK_PARSE_STATE_GOT_SYSID:
|
---|
661 | rxmsg->compid = c;
|
---|
662 | mavlink_update_checksum(rxmsg, c);
|
---|
663 | status->parse_state = MAVLINK_PARSE_STATE_GOT_COMPID;
|
---|
664 | break;
|
---|
665 |
|
---|
666 | case MAVLINK_PARSE_STATE_GOT_COMPID:
|
---|
667 | rxmsg->msgid = c;
|
---|
668 | mavlink_update_checksum(rxmsg, c);
|
---|
669 | if (status->flags & MAVLINK_STATUS_FLAG_IN_MAVLINK1) {
|
---|
670 | status->parse_state = MAVLINK_PARSE_STATE_GOT_MSGID3;
|
---|
671 | #ifdef MAVLINK_CHECK_MESSAGE_LENGTH
|
---|
672 | if (rxmsg->len != MAVLINK_MESSAGE_LENGTH(rxmsg->msgid))
|
---|
673 | {
|
---|
674 | _mav_parse_error(status);
|
---|
675 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
676 | break;
|
---|
677 | }
|
---|
678 | #endif
|
---|
679 | } else {
|
---|
680 | status->parse_state = MAVLINK_PARSE_STATE_GOT_MSGID1;
|
---|
681 | }
|
---|
682 | break;
|
---|
683 |
|
---|
684 | case MAVLINK_PARSE_STATE_GOT_MSGID1:
|
---|
685 | rxmsg->msgid |= c<<8;
|
---|
686 | mavlink_update_checksum(rxmsg, c);
|
---|
687 | status->parse_state = MAVLINK_PARSE_STATE_GOT_MSGID2;
|
---|
688 | break;
|
---|
689 |
|
---|
690 | case MAVLINK_PARSE_STATE_GOT_MSGID2:
|
---|
691 | rxmsg->msgid |= c<<16;
|
---|
692 | mavlink_update_checksum(rxmsg, c);
|
---|
693 | status->parse_state = MAVLINK_PARSE_STATE_GOT_MSGID3;
|
---|
694 | #ifdef MAVLINK_CHECK_MESSAGE_LENGTH
|
---|
695 | if (rxmsg->len != MAVLINK_MESSAGE_LENGTH(rxmsg->msgid))
|
---|
696 | {
|
---|
697 | _mav_parse_error(status);
|
---|
698 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
699 | break;
|
---|
700 | }
|
---|
701 | #endif
|
---|
702 | break;
|
---|
703 |
|
---|
704 | case MAVLINK_PARSE_STATE_GOT_MSGID3:
|
---|
705 | _MAV_PAYLOAD_NON_CONST(rxmsg)[status->packet_idx++] = (char)c;
|
---|
706 | mavlink_update_checksum(rxmsg, c);
|
---|
707 | if (status->packet_idx == rxmsg->len)
|
---|
708 | {
|
---|
709 | status->parse_state = MAVLINK_PARSE_STATE_GOT_PAYLOAD;
|
---|
710 | }
|
---|
711 | break;
|
---|
712 |
|
---|
713 | case MAVLINK_PARSE_STATE_GOT_PAYLOAD: {
|
---|
714 | const mavlink_msg_entry_t *e = mavlink_get_msg_entry(rxmsg->msgid);
|
---|
715 | uint8_t crc_extra = e?e->crc_extra:0;
|
---|
716 | mavlink_update_checksum(rxmsg, crc_extra);
|
---|
717 | if (c != (rxmsg->checksum & 0xFF)) {
|
---|
718 | status->parse_state = MAVLINK_PARSE_STATE_GOT_BAD_CRC1;
|
---|
719 | } else {
|
---|
720 | status->parse_state = MAVLINK_PARSE_STATE_GOT_CRC1;
|
---|
721 | }
|
---|
722 | rxmsg->ck[0] = c;
|
---|
723 |
|
---|
724 | // zero-fill the packet to cope with short incoming packets
|
---|
725 | if (e && status->packet_idx < e->msg_len) {
|
---|
726 | memset(&_MAV_PAYLOAD_NON_CONST(rxmsg)[status->packet_idx], 0, e->msg_len - status->packet_idx);
|
---|
727 | }
|
---|
728 | break;
|
---|
729 | }
|
---|
730 |
|
---|
731 | case MAVLINK_PARSE_STATE_GOT_CRC1:
|
---|
732 | case MAVLINK_PARSE_STATE_GOT_BAD_CRC1:
|
---|
733 | if (status->parse_state == MAVLINK_PARSE_STATE_GOT_BAD_CRC1 || c != (rxmsg->checksum >> 8)) {
|
---|
734 | // got a bad CRC message
|
---|
735 | status->msg_received = MAVLINK_FRAMING_BAD_CRC;
|
---|
736 | } else {
|
---|
737 | // Successfully got message
|
---|
738 | status->msg_received = MAVLINK_FRAMING_OK;
|
---|
739 | }
|
---|
740 | rxmsg->ck[1] = c;
|
---|
741 | if (rxmsg->incompat_flags & MAVLINK_IFLAG_SIGNED) {
|
---|
742 | status->parse_state = MAVLINK_PARSE_STATE_SIGNATURE_WAIT;
|
---|
743 | status->signature_wait = MAVLINK_SIGNATURE_BLOCK_LEN;
|
---|
744 | status->msg_received = MAVLINK_FRAMING_INCOMPLETE;
|
---|
745 | } else {
|
---|
746 | if (status->signing &&
|
---|
747 | (status->signing->accept_unsigned_callback == NULL ||
|
---|
748 | !status->signing->accept_unsigned_callback(status, rxmsg->msgid))) {
|
---|
749 | // don't accept this unsigned packet
|
---|
750 | status->msg_received = MAVLINK_FRAMING_BAD_SIGNATURE;
|
---|
751 | }
|
---|
752 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
753 | memcpy(r_message, rxmsg, sizeof(mavlink_message_t));
|
---|
754 | }
|
---|
755 | break;
|
---|
756 | case MAVLINK_PARSE_STATE_SIGNATURE_WAIT:
|
---|
757 | rxmsg->signature[MAVLINK_SIGNATURE_BLOCK_LEN-status->signature_wait] = c;
|
---|
758 | status->signature_wait--;
|
---|
759 | if (status->signature_wait == 0) {
|
---|
760 | // we have the whole signature, check it is OK
|
---|
761 | bool sig_ok = mavlink_signature_check(status->signing, status->signing_streams, rxmsg);
|
---|
762 | if (!sig_ok &&
|
---|
763 | (status->signing->accept_unsigned_callback &&
|
---|
764 | status->signing->accept_unsigned_callback(status, rxmsg->msgid))) {
|
---|
765 | // accepted via application level override
|
---|
766 | sig_ok = true;
|
---|
767 | }
|
---|
768 | if (sig_ok) {
|
---|
769 | status->msg_received = MAVLINK_FRAMING_OK;
|
---|
770 | } else {
|
---|
771 | status->msg_received = MAVLINK_FRAMING_BAD_SIGNATURE;
|
---|
772 | }
|
---|
773 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
774 | memcpy(r_message, rxmsg, sizeof(mavlink_message_t));
|
---|
775 | }
|
---|
776 | break;
|
---|
777 | }
|
---|
778 |
|
---|
779 | bufferIndex++;
|
---|
780 | // If a message has been sucessfully decoded, check index
|
---|
781 | if (status->msg_received == MAVLINK_FRAMING_OK)
|
---|
782 | {
|
---|
783 | //while(status->current_seq != rxmsg->seq)
|
---|
784 | //{
|
---|
785 | // status->packet_rx_drop_count++;
|
---|
786 | // status->current_seq++;
|
---|
787 | //}
|
---|
788 | status->current_rx_seq = rxmsg->seq;
|
---|
789 | // Initial condition: If no packet has been received so far, drop count is undefined
|
---|
790 | if (status->packet_rx_success_count == 0) status->packet_rx_drop_count = 0;
|
---|
791 | // Count this packet as received
|
---|
792 | status->packet_rx_success_count++;
|
---|
793 | }
|
---|
794 |
|
---|
795 | r_message->len = rxmsg->len; // Provide visibility on how far we are into current msg
|
---|
796 | r_mavlink_status->parse_state = status->parse_state;
|
---|
797 | r_mavlink_status->packet_idx = status->packet_idx;
|
---|
798 | r_mavlink_status->current_rx_seq = status->current_rx_seq+1;
|
---|
799 | r_mavlink_status->packet_rx_success_count = status->packet_rx_success_count;
|
---|
800 | r_mavlink_status->packet_rx_drop_count = status->parse_error;
|
---|
801 | r_mavlink_status->flags = status->flags;
|
---|
802 | status->parse_error = 0;
|
---|
803 |
|
---|
804 | if (status->msg_received == MAVLINK_FRAMING_BAD_CRC) {
|
---|
805 | /*
|
---|
806 | the CRC came out wrong. We now need to overwrite the
|
---|
807 | msg CRC with the one on the wire so that if the
|
---|
808 | caller decides to forward the message anyway that
|
---|
809 | mavlink_msg_to_send_buffer() won't overwrite the
|
---|
810 | checksum
|
---|
811 | */
|
---|
812 | r_message->checksum = rxmsg->ck[0] | (rxmsg->ck[1]<<8);
|
---|
813 | }
|
---|
814 |
|
---|
815 | return status->msg_received;
|
---|
816 | }
|
---|
817 |
|
---|
818 | /**
|
---|
819 | * This is a convenience function which handles the complete MAVLink parsing.
|
---|
820 | * the function will parse one byte at a time and return the complete packet once
|
---|
821 | * it could be successfully decoded. This function will return 0, 1 or
|
---|
822 | * 2 (MAVLINK_FRAMING_INCOMPLETE, MAVLINK_FRAMING_OK or MAVLINK_FRAMING_BAD_CRC)
|
---|
823 | *
|
---|
824 | * Messages are parsed into an internal buffer (one for each channel). When a complete
|
---|
825 | * message is received it is copies into *returnMsg and the channel's status is
|
---|
826 | * copied into *returnStats.
|
---|
827 | *
|
---|
828 | * @param chan ID of the current channel. This allows to parse different channels with this function.
|
---|
829 | * a channel is not a physical message channel like a serial port, but a logic partition of
|
---|
830 | * the communication streams in this case. COMM_NB is the limit for the number of channels
|
---|
831 | * on MCU (e.g. ARM7), while COMM_NB_HIGH is the limit for the number of channels in Linux/Windows
|
---|
832 | * @param c The char to parse
|
---|
833 | *
|
---|
834 | * @param returnMsg NULL if no message could be decoded, the message data else
|
---|
835 | * @param returnStats if a message was decoded, this is filled with the channel's stats
|
---|
836 | * @return 0 if no message could be decoded, 1 on good message and CRC, 2 on bad CRC
|
---|
837 | *
|
---|
838 | * A typical use scenario of this function call is:
|
---|
839 | *
|
---|
840 | * @code
|
---|
841 | * #include <mavlink.h>
|
---|
842 | *
|
---|
843 | * mavlink_message_t msg;
|
---|
844 | * int chan = 0;
|
---|
845 | *
|
---|
846 | *
|
---|
847 | * while(serial.bytesAvailable > 0)
|
---|
848 | * {
|
---|
849 | * uint8_t byte = serial.getNextByte();
|
---|
850 | * if (mavlink_frame_char(chan, byte, &msg) != MAVLINK_FRAMING_INCOMPLETE)
|
---|
851 | * {
|
---|
852 | * printf("Received message with ID %d, sequence: %d from component %d of system %d", msg.msgid, msg.seq, msg.compid, msg.sysid);
|
---|
853 | * }
|
---|
854 | * }
|
---|
855 | *
|
---|
856 | *
|
---|
857 | * @endcode
|
---|
858 | */
|
---|
859 | MAVLINK_HELPER uint8_t mavlink_frame_char(uint8_t chan, uint8_t c, mavlink_message_t* r_message, mavlink_status_t* r_mavlink_status)
|
---|
860 | {
|
---|
861 | return mavlink_frame_char_buffer(mavlink_get_channel_buffer(chan),
|
---|
862 | mavlink_get_channel_status(chan),
|
---|
863 | c,
|
---|
864 | r_message,
|
---|
865 | r_mavlink_status);
|
---|
866 | }
|
---|
867 |
|
---|
868 | /**
|
---|
869 | * Set the protocol version
|
---|
870 | */
|
---|
871 | MAVLINK_HELPER void mavlink_set_proto_version(uint8_t chan, unsigned int version)
|
---|
872 | {
|
---|
873 | mavlink_status_t *status = mavlink_get_channel_status(chan);
|
---|
874 | if (version > 1) {
|
---|
875 | status->flags &= ~(MAVLINK_STATUS_FLAG_OUT_MAVLINK1);
|
---|
876 | } else {
|
---|
877 | status->flags |= MAVLINK_STATUS_FLAG_OUT_MAVLINK1;
|
---|
878 | }
|
---|
879 | }
|
---|
880 |
|
---|
881 | /**
|
---|
882 | * Get the protocol version
|
---|
883 | *
|
---|
884 | * @return 1 for v1, 2 for v2
|
---|
885 | */
|
---|
886 | MAVLINK_HELPER unsigned int mavlink_get_proto_version(uint8_t chan, unsigned int version)
|
---|
887 | {
|
---|
888 | mavlink_status_t *status = mavlink_get_channel_status(chan);
|
---|
889 | if ((status->flags & MAVLINK_STATUS_FLAG_OUT_MAVLINK1) > 0) {
|
---|
890 | return 1;
|
---|
891 | } else {
|
---|
892 | return 2;
|
---|
893 | }
|
---|
894 | }
|
---|
895 |
|
---|
896 | /**
|
---|
897 | * This is a convenience function which handles the complete MAVLink parsing.
|
---|
898 | * the function will parse one byte at a time and return the complete packet once
|
---|
899 | * it could be successfully decoded. This function will return 0 or 1.
|
---|
900 | *
|
---|
901 | * Messages are parsed into an internal buffer (one for each channel). When a complete
|
---|
902 | * message is received it is copies into *returnMsg and the channel's status is
|
---|
903 | * copied into *returnStats.
|
---|
904 | *
|
---|
905 | * @param chan ID of the current channel. This allows to parse different channels with this function.
|
---|
906 | * a channel is not a physical message channel like a serial port, but a logic partition of
|
---|
907 | * the communication streams in this case. COMM_NB is the limit for the number of channels
|
---|
908 | * on MCU (e.g. ARM7), while COMM_NB_HIGH is the limit for the number of channels in Linux/Windows
|
---|
909 | * @param c The char to parse
|
---|
910 | *
|
---|
911 | * @param returnMsg NULL if no message could be decoded, the message data else
|
---|
912 | * @param returnStats if a message was decoded, this is filled with the channel's stats
|
---|
913 | * @return 0 if no message could be decoded or bad CRC, 1 on good message and CRC
|
---|
914 | *
|
---|
915 | * A typical use scenario of this function call is:
|
---|
916 | *
|
---|
917 | * @code
|
---|
918 | * #include <mavlink.h>
|
---|
919 | *
|
---|
920 | * mavlink_message_t msg;
|
---|
921 | * int chan = 0;
|
---|
922 | *
|
---|
923 | *
|
---|
924 | * while(serial.bytesAvailable > 0)
|
---|
925 | * {
|
---|
926 | * uint8_t byte = serial.getNextByte();
|
---|
927 | * if (mavlink_parse_char(chan, byte, &msg))
|
---|
928 | * {
|
---|
929 | * printf("Received message with ID %d, sequence: %d from component %d of system %d", msg.msgid, msg.seq, msg.compid, msg.sysid);
|
---|
930 | * }
|
---|
931 | * }
|
---|
932 | *
|
---|
933 | *
|
---|
934 | * @endcode
|
---|
935 | */
|
---|
936 | MAVLINK_HELPER uint8_t mavlink_parse_char(uint8_t chan, uint8_t c, mavlink_message_t* r_message, mavlink_status_t* r_mavlink_status)
|
---|
937 | {
|
---|
938 | uint8_t msg_received = mavlink_frame_char(chan, c, r_message, r_mavlink_status);
|
---|
939 | if (msg_received == MAVLINK_FRAMING_BAD_CRC ||
|
---|
940 | msg_received == MAVLINK_FRAMING_BAD_SIGNATURE) {
|
---|
941 | // we got a bad CRC. Treat as a parse failure
|
---|
942 | mavlink_message_t* rxmsg = mavlink_get_channel_buffer(chan);
|
---|
943 | mavlink_status_t* status = mavlink_get_channel_status(chan);
|
---|
944 | _mav_parse_error(status);
|
---|
945 | status->msg_received = MAVLINK_FRAMING_INCOMPLETE;
|
---|
946 | status->parse_state = MAVLINK_PARSE_STATE_IDLE;
|
---|
947 | if (c == MAVLINK_STX)
|
---|
948 | {
|
---|
949 | status->parse_state = MAVLINK_PARSE_STATE_GOT_STX;
|
---|
950 | rxmsg->len = 0;
|
---|
951 | mavlink_start_checksum(rxmsg);
|
---|
952 | }
|
---|
953 | return 0;
|
---|
954 | }
|
---|
955 | return msg_received;
|
---|
956 | }
|
---|
957 |
|
---|
958 | /**
|
---|
959 | * @brief Put a bitfield of length 1-32 bit into the buffer
|
---|
960 | *
|
---|
961 | * @param b the value to add, will be encoded in the bitfield
|
---|
962 | * @param bits number of bits to use to encode b, e.g. 1 for boolean, 2, 3, etc.
|
---|
963 | * @param packet_index the position in the packet (the index of the first byte to use)
|
---|
964 | * @param bit_index the position in the byte (the index of the first bit to use)
|
---|
965 | * @param buffer packet buffer to write into
|
---|
966 | * @return new position of the last used byte in the buffer
|
---|
967 | */
|
---|
968 | MAVLINK_HELPER uint8_t put_bitfield_n_by_index(int32_t b, uint8_t bits, uint8_t packet_index, uint8_t bit_index, uint8_t* r_bit_index, uint8_t* buffer)
|
---|
969 | {
|
---|
970 | uint16_t bits_remain = bits;
|
---|
971 | // Transform number into network order
|
---|
972 | int32_t v;
|
---|
973 | uint8_t i_bit_index, i_byte_index, curr_bits_n;
|
---|
974 | #if MAVLINK_NEED_BYTE_SWAP
|
---|
975 | union {
|
---|
976 | int32_t i;
|
---|
977 | uint8_t b[4];
|
---|
978 | } bin, bout;
|
---|
979 | bin.i = b;
|
---|
980 | bout.b[0] = bin.b[3];
|
---|
981 | bout.b[1] = bin.b[2];
|
---|
982 | bout.b[2] = bin.b[1];
|
---|
983 | bout.b[3] = bin.b[0];
|
---|
984 | v = bout.i;
|
---|
985 | #else
|
---|
986 | v = b;
|
---|
987 | #endif
|
---|
988 |
|
---|
989 | // buffer in
|
---|
990 | // 01100000 01000000 00000000 11110001
|
---|
991 | // buffer out
|
---|
992 | // 11110001 00000000 01000000 01100000
|
---|
993 |
|
---|
994 | // Existing partly filled byte (four free slots)
|
---|
995 | // 0111xxxx
|
---|
996 |
|
---|
997 | // Mask n free bits
|
---|
998 | // 00001111 = 2^0 + 2^1 + 2^2 + 2^3 = 2^n - 1
|
---|
999 | // = ((uint32_t)(1 << n)) - 1; // = 2^n - 1
|
---|
1000 |
|
---|
1001 | // Shift n bits into the right position
|
---|
1002 | // out = in >> n;
|
---|
1003 |
|
---|
1004 | // Mask and shift bytes
|
---|
1005 | i_bit_index = bit_index;
|
---|
1006 | i_byte_index = packet_index;
|
---|
1007 | if (bit_index > 0)
|
---|
1008 | {
|
---|
1009 | // If bits were available at start, they were available
|
---|
1010 | // in the byte before the current index
|
---|
1011 | i_byte_index--;
|
---|
1012 | }
|
---|
1013 |
|
---|
1014 | // While bits have not been packed yet
|
---|
1015 | while (bits_remain > 0)
|
---|
1016 | {
|
---|
1017 | // Bits still have to be packed
|
---|
1018 | // there can be more than 8 bits, so
|
---|
1019 | // we might have to pack them into more than one byte
|
---|
1020 |
|
---|
1021 | // First pack everything we can into the current 'open' byte
|
---|
1022 | //curr_bits_n = bits_remain << 3; // Equals bits_remain mod 8
|
---|
1023 | //FIXME
|
---|
1024 | if (bits_remain <= (uint8_t)(8 - i_bit_index))
|
---|
1025 | {
|
---|
1026 | // Enough space
|
---|
1027 | curr_bits_n = (uint8_t)bits_remain;
|
---|
1028 | }
|
---|
1029 | else
|
---|
1030 | {
|
---|
1031 | curr_bits_n = (8 - i_bit_index);
|
---|
1032 | }
|
---|
1033 |
|
---|
1034 | // Pack these n bits into the current byte
|
---|
1035 | // Mask out whatever was at that position with ones (xxx11111)
|
---|
1036 | buffer[i_byte_index] &= (0xFF >> (8 - curr_bits_n));
|
---|
1037 | // Put content to this position, by masking out the non-used part
|
---|
1038 | buffer[i_byte_index] |= ((0x00 << curr_bits_n) & v);
|
---|
1039 |
|
---|
1040 | // Increment the bit index
|
---|
1041 | i_bit_index += curr_bits_n;
|
---|
1042 |
|
---|
1043 | // Now proceed to the next byte, if necessary
|
---|
1044 | bits_remain -= curr_bits_n;
|
---|
1045 | if (bits_remain > 0)
|
---|
1046 | {
|
---|
1047 | // Offer another 8 bits / one byte
|
---|
1048 | i_byte_index++;
|
---|
1049 | i_bit_index = 0;
|
---|
1050 | }
|
---|
1051 | }
|
---|
1052 |
|
---|
1053 | *r_bit_index = i_bit_index;
|
---|
1054 | // If a partly filled byte is present, mark this as consumed
|
---|
1055 | if (i_bit_index != 7) i_byte_index++;
|
---|
1056 | return i_byte_index - packet_index;
|
---|
1057 | }
|
---|
1058 |
|
---|
1059 | #ifdef MAVLINK_USE_CONVENIENCE_FUNCTIONS
|
---|
1060 |
|
---|
1061 | // To make MAVLink work on your MCU, define comm_send_ch() if you wish
|
---|
1062 | // to send 1 byte at a time, or MAVLINK_SEND_UART_BYTES() to send a
|
---|
1063 | // whole packet at a time
|
---|
1064 |
|
---|
1065 | /*
|
---|
1066 |
|
---|
1067 | #include "mavlink_types.h"
|
---|
1068 |
|
---|
1069 | void comm_send_ch(mavlink_channel_t chan, uint8_t ch)
|
---|
1070 | {
|
---|
1071 | if (chan == MAVLINK_COMM_0)
|
---|
1072 | {
|
---|
1073 | uart0_transmit(ch);
|
---|
1074 | }
|
---|
1075 | if (chan == MAVLINK_COMM_1)
|
---|
1076 | {
|
---|
1077 | uart1_transmit(ch);
|
---|
1078 | }
|
---|
1079 | }
|
---|
1080 | */
|
---|
1081 |
|
---|
1082 | MAVLINK_HELPER void _mavlink_send_uart(mavlink_channel_t chan, const char *buf, uint16_t len)
|
---|
1083 | {
|
---|
1084 | #ifdef MAVLINK_SEND_UART_BYTES
|
---|
1085 | /* this is the more efficient approach, if the platform
|
---|
1086 | defines it */
|
---|
1087 | MAVLINK_SEND_UART_BYTES(chan, (const uint8_t *)buf, len);
|
---|
1088 | #else
|
---|
1089 | /* fallback to one byte at a time */
|
---|
1090 | uint16_t i;
|
---|
1091 | for (i = 0; i < len; i++) {
|
---|
1092 | comm_send_ch(chan, (uint8_t)buf[i]);
|
---|
1093 | }
|
---|
1094 | #endif
|
---|
1095 | }
|
---|
1096 | #endif // MAVLINK_USE_CONVENIENCE_FUNCTIONS
|
---|
1097 |
|
---|
1098 | #endif /* _MAVLINK_HELPERS_H_ */
|
---|
1099 |
|
---|
1100 |
|
---|