diff --git a/src/crc.c b/src/crc.c index ed17ed5..b6fc2b6 100644 --- a/src/crc.c +++ b/src/crc.c @@ -3,87 +3,66 @@ static const uint8_t CRC8_TABLE[] = { - 0 ,94 ,188,226,97 ,63 ,221,131,194,156,126,32 ,163,253,31 ,65 , - 157,195,33 ,127,252,162,64 ,30 ,95 ,1 ,227,189,62 ,96 ,130,220, - 35 ,125,159,193,66 ,28 ,254,160,225,191,93 ,3 ,128,222,60 ,98 , - 190,224,2 ,92 ,223,129,99 ,61 ,124,34 ,192,158,29 ,67 ,161,255, - 70 ,24 ,250,164,39 ,121,155,197,132,218,56 ,102,229,187,89 ,7 , - 219,133,103,57 ,186,228,6 ,88 ,25 ,71 ,165,251,120,38 ,196,154, - 101,59 ,217,135,4 ,90 ,184,230,167,249,27 ,69 ,198,152,122,36 , - 248,166,68 ,26 ,153,199,37 ,123,58 ,100,134,216,91 ,5 ,231,185, - 140,210,48 ,110,237,179,81 ,15 ,78 ,16 ,242,172,47 ,113,147,205, - 17 ,79 ,173,243,112,46 ,204,146,211,141,111,49 ,178,236,14 ,80 , - 175,241,19 ,77 ,206,144,114,44 ,109,51 ,209,143,12 ,82 ,176,238, - 50 ,108,142,208,83 ,13 ,239,177,240,174,76 ,18 ,145,207,45 ,115, - 202,148,118,40 ,171,245,23 ,73 ,8 ,86 ,180,234,105,55 ,213,139, - 87 ,9 ,235,181,54 ,104,138,212,149,203,41 ,119,244,170,72 ,22 , - 233,183,85 ,11 ,136,214,52 ,106,43 ,117,151,201,74 ,20 ,246,168, - 116,42 ,200,150,21 ,75 ,169,247,182,232,10 ,84 ,215,137,107,53 + 0x00, 0x5e, 0xbc, 0xe2, 0x61, 0x3f, 0xdd, 0x83, 0xc2, 0x9c, 0x7e, 0x20, + 0xa3, 0xfd, 0x1f, 0x41, 0x9d, 0xc3, 0x21, 0x7f, 0xfc, 0xa2, 0x40, 0x1e, + 0x5f, 0x01, 0xe3, 0xbd, 0x3e, 0x60, 0x82, 0xdc, 0x23, 0x7d, 0x9f, 0xc1, + 0x42, 0x1c, 0xfe, 0xa0, 0xe1, 0xbf, 0x5d, 0x03, 0x80, 0xde, 0x3c, 0x62, + 0xbe, 0xe0, 0x02, 0x5c, 0xdf, 0x81, 0x63, 0x3d, 0x7c, 0x22, 0xc0, 0x9e, + 0x1d, 0x43, 0xa1, 0xff, 0x46, 0x18, 0xfa, 0xa4, 0x27, 0x79, 0x9b, 0xc5, + 0x84, 0xda, 0x38, 0x66, 0xe5, 0xbb, 0x59, 0x07, 0xdb, 0x85, 0x67, 0x39, + 0xba, 0xe4, 0x06, 0x58, 0x19, 0x47, 0xa5, 0xfb, 0x78, 0x26, 0xc4, 0x9a, + 0x65, 0x3b, 0xd9, 0x87, 0x04, 0x5a, 0xb8, 0xe6, 0xa7, 0xf9, 0x1b, 0x45, + 0xc6, 0x98, 0x7a, 0x24, 0xf8, 0xa6, 0x44, 0x1a, 0x99, 0xc7, 0x25, 0x7b, + 0x3a, 0x64, 0x86, 0xd8, 0x5b, 0x05, 0xe7, 0xb9, 0x8c, 0xd2, 0x30, 0x6e, + 0xed, 0xb3, 0x51, 0x0f, 0x4e, 0x10, 0xf2, 0xac, 0x2f, 0x71, 0x93, 0xcd, + 0x11, 0x4f, 0xad, 0xf3, 0x70, 0x2e, 0xcc, 0x92, 0xd3, 0x8d, 0x6f, 0x31, + 0xb2, 0xec, 0x0e, 0x50, 0xaf, 0xf1, 0x13, 0x4d, 0xce, 0x90, 0x72, 0x2c, + 0x6d, 0x33, 0xd1, 0x8f, 0x0c, 0x52, 0xb0, 0xee, 0x32, 0x6c, 0x8e, 0xd0, + 0x53, 0x0d, 0xef, 0xb1, 0xf0, 0xae, 0x4c, 0x12, 0x91, 0xcf, 0x2d, 0x73, + 0xca, 0x94, 0x76, 0x28, 0xab, 0xf5, 0x17, 0x49, 0x08, 0x56, 0xb4, 0xea, + 0x69, 0x37, 0xd5, 0x8b, 0x57, 0x09, 0xeb, 0xb5, 0x36, 0x68, 0x8a, 0xd4, + 0x95, 0xcb, 0x29, 0x77, 0xf4, 0xaa, 0x48, 0x16, 0xe9, 0xb7, 0x55, 0x0b, + 0x88, 0xd6, 0x34, 0x6a, 0x2b, 0x75, 0x97, 0xc9, 0x4a, 0x14, 0xf6, 0xa8, + 0x74, 0x2a, 0xc8, 0x96, 0x15, 0x4b, 0xa9, 0xf7, 0xb6, 0xe8, 0x0a, 0x54, + 0xd7, 0x89, 0x6b, 0x35 }; -static const uint8_t CRC16_HIGH_TABLE[] = +static const uint16_t CRC16_TABLE[] = { - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, - 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, - 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, - 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, - 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, - 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, - 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, - 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, - 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, - 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, - 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, - 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, - 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, - 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, - 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40 -}; - -static const int8_t CRC16_LOW_TABLE[] = -{ - 0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, - 0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, - 0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, - 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A, - 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4, - 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3, - 0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, - 0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, - 0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, - 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29, - 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED, - 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26, - 0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, - 0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, - 0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, - 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68, - 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E, - 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5, - 0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, - 0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, - 0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, - 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B, - 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B, - 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C, - 0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, - 0x43, 0x83, 0x41, 0x81, 0x80, 0x40 + 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, + 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 0x1081, 0x0108, + 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0x9cc9, 0x8d40, 0xbfdb, + 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 0x2102, 0x308b, 0x0210, 0x1399, + 0x6726, 0x76af, 0x4434, 0x55bd, 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, + 0xfae7, 0xc87c, 0xd9f5, 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, + 0x54b5, 0x453c, 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, + 0xc974, 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, + 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285, + 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, + 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, 0x6306, 0x728f, 0x4014, + 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5, + 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, + 0x242a, 0x16b1, 0x0738, 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, + 0x9af9, 0x8b70, 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, + 0xf0b7, 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, + 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, + 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 0xa50a, 0xb483, + 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 0x2942, 0x38cb, 0x0a50, + 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 0xb58b, 0xa402, 0x9699, 0x8710, + 0xf3af, 0xe226, 0xd0bd, 0xc134, 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, + 0x6e6e, 0x5cf5, 0x4d7c, 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, + 0xa33a, 0xb2b3, 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, + 0x3efb, 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, + 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e, + 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, + 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, 0xf78f, 0xe606, 0xd49d, + 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c, + 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 }; uint8_t crc8(const void* block, size_t length) { - uint8_t crc = 0; + uint8_t crc = 0x77; const uint8_t* bytes = (uint8_t*)block; while(length--) crc = CRC8_TABLE[crc^*bytes++]; return crc; @@ -91,14 +70,9 @@ uint8_t crc8(const void* block, size_t length) uint16_t crc16(const void* block, size_t length) { - uint8_t crch = 0XFF, crcl = 0XFF; + uint16_t crc = 0x3692; const uint8_t* bytes = (uint8_t*)block; - size_t i; while(length--) - { - i = crcl ^ *bytes++; - crcl = crch ^ CRC16_HIGH_TABLE[i]; - crch = CRC16_LOW_TABLE[i]; - } - return (((uint16_t)(crch<<8))|crcl); + crc = ((crc>>8)&0xFF)^CRC16_TABLE[((crc^*bytes++)&0xFF)]; + return crc; } diff --git a/src/robomaster.c b/src/robomaster.c index adfceb0..1cdd75f 100644 --- a/src/robomaster.c +++ b/src/robomaster.c @@ -13,6 +13,8 @@ struct Session* session_new(void* buffer, size_t size) { session->size = 0; session->seq = RM_SDK_FIRST_SEQ_ID; session->max_size = size; + // TODO: Make this configurable + session->hostbyte = host2byte(DEFAULT_CLIENT_HOST, DEFAULT_CLIENT_INDEX); return session; } @@ -25,21 +27,25 @@ struct Message* message_new(struct Session* session, uint8_t cmdset, uint8_t cmdid, size_t length, const void* body) { struct Message* message = session->buffer + session->size; + memcpy((void*)message->body, body, length); length += sizeof(struct Header) + sizeof(struct Footer); session->size += length; + int16_t seq = ++session->seq; message->header.preamble = 0x55; - message->header.length = htons(length & 0xff03 | 4); + message->header.length_l = length & 0xFF; + message->header.length_h = (length >> 8) & 0x3 | 4; message->header.crc = crc8(message, 3); - message->header.seq_id = htons(session->seq++); + message->header.seq_id = seq; + message->header.sender = session->hostbyte; + message->header.receiver = host2byte(DEFAULT_CLIENT_HOST, DEFAULT_ROBOT_INDEX); message->header.ack_needed = true; message->header.cmdset = cmdset; message->header.cmdid = cmdid; - memcpy((void*)message->body, body, length); - struct Footer* footer = (void*)message + length - sizeof(struct Footer); - footer->crc = htons(crc16(message, length - 2)); + uint16_t crc = crc16(message, length - sizeof(struct Footer)); + footer->crc = crc; return message; @@ -49,10 +55,9 @@ message_new(struct Session* session, uint8_t cmdset, uint8_t cmdid, size_t lengt const Message set_sdk_connection_req_new ( Session session, - const struct SetSdkConnectionReq* msg ) { + struct SetSdkConnectionReq* msg ) { + msg->host = session->hostbyte; struct Message* message = message_new(session, 0x3F, SET_SDK_CONNECTION_CMDID, sizeof(struct SetSdkConnectionReq), msg); - struct SetSdkConnectionReq* body = (struct SetSdkConnectionReq*)message->body; - body->port = htons(body->port); return message; } diff --git a/src/robomaster.h b/src/robomaster.h index b20ee87..e1556f2 100644 --- a/src/robomaster.h +++ b/src/robomaster.h @@ -7,15 +7,29 @@ // Move to private header uint8_t crc8(const void *block, size_t length); -uint8_t crc16(const void *block, size_t length); +uint16_t crc16(const void *block, size_t length); -struct Header { +#define PACKED __attribute__((__packed__)) + +struct PACKED Header { uint8_t preamble; - uint16_t length; + union { + uint16_t length; + struct { + uint8_t length_l; + uint8_t length_h; + }; + }; uint8_t crc; uint8_t sender; uint8_t receiver; - uint16_t seq_id; + union { + int16_t seq_id; + struct { + uint8_t seq_id_l; + uint8_t seq_id_h; + }; + }; union { uint8_t attribute; struct { @@ -28,20 +42,26 @@ struct Header { uint8_t cmdid; }; -struct Message { +struct PACKED Message { struct Header header; uint8_t body[]; }; -struct Footer { +struct PACKED Footer { uint16_t crc; }; +// TODO: Rename to Client struct Session { + void* buffer; size_t max_size; size_t size; - uint16_t seq; + + uint8_t hostbyte; + + int16_t seq; + }; struct Message* message_new(struct Session* session, uint8_t cmdset, uint8_t cmdid, size_t length, const void* body); @@ -55,16 +75,32 @@ Session session_new(void* buffer, size_t size); size_t session_size(Session session); // SEQ ID will loop around -static const uint16_t RM_SDK_FIRST_SEQ_ID = 10000; -static const uint16_t RM_SDK_LAST_SEQ_ID = 20000; +static const int16_t RM_SDK_FIRST_SEQ_ID = 11239; +static const int16_t RM_SDK_LAST_SEQ_ID = 20000; static const uint8_t CONNECTION_WIFI_AP = 0; static const uint8_t CONNECTION_WIFI_STA = 1; static const uint8_t CONNECTION_USB_RNDIS = 2; +// Not sure what these are for, but they are used for the hostbyte +static const uint8_t DEFAULT_CLIENT_HOST = 9; +static const uint8_t DEFAULT_CLIENT_INDEX = 6; +static const uint8_t DEFAULT_ROBOT_INDEX = 0; + +static inline uint8_t host2byte(uint8_t host, uint8_t index) { + return index * 32 + host; +} + +static inline void byte2host(uint8_t b, uint8_t* host, uint8_t* index) { + *host = (b & 0x1F); + *index = b >> 5; +} + +////// + static const uint8_t SET_SDK_CONNECTION_CMDID = 0xD4; -struct SetSdkConnectionReq { +struct PACKED SetSdkConnectionReq { uint8_t control; uint8_t host; uint8_t connection; @@ -73,20 +109,24 @@ struct SetSdkConnectionReq { uint16_t port; }; -struct SetSdkConnectionResp { +struct PACKED SetSdkConnectionResp { uint8_t retcode; uint8_t state; uint32_t config_ip; }; -const Message set_sdk_connection_req_new(Session session, const struct SetSdkConnectionReq* msg); +const Message set_sdk_connection_req_new(Session session, struct SetSdkConnectionReq* msg); static const uint8_t GET_VERSION_CMDID = 0x01; -struct GetVersionResp { +// NOTE: No GetVersion request body + +struct PACKED GetVersionResp { uint8_t retcode; uint8_t aa; uint8_t bb; uint8_t cc; uint8_t dd; }; + +const Message get_version_req_new(Session session); diff --git a/src/robomastersh.c b/src/robomastersh.c index 9930d8a..6968641 100644 --- a/src/robomastersh.c +++ b/src/robomastersh.c @@ -2,6 +2,7 @@ #include #include +#include uint8_t buffer[1024] = {0}; uint8_t recvbuff[1024] = {0}; @@ -15,7 +16,8 @@ int main(int argc, char* argv[]) req.connection = CONNECTION_WIFI_AP; req.protocol = 0; req.ip_address = 0; - req.port = 10010; + //req.port = 10010; + req.port = 10242; const Message msg = set_sdk_connection_req_new(session, &req); int sockfd = socket(AF_INET, SOCK_DGRAM, 0); @@ -26,12 +28,28 @@ int main(int argc, char* argv[]) dest_addr.sin_addr.s_addr = inet_addr("192.168.2.1"); sendto(sockfd, buffer, session_size(session), 0, (struct sockaddr*)&dest_addr, addrlen); - addrlen = sizeof(dest_addr); - recvfrom(sockfd, &recvbuff, sizeof(struct Header), 0, (struct sockaddr*)&dest_addr, &addrlen); + int recvb = recvfrom(sockfd, &recvbuff, sizeof(recvbuff), 0, (struct sockaddr*)&dest_addr, &addrlen); struct Message* resp = (struct Message*)recvbuff; - addrlen = sizeof(dest_addr); + + // check length uint16_t resplen = (recvbuff[2] & 0x3) * 0xFF + recvbuff[1]; - recvfrom(sockfd, resp->body, resplen - sizeof(struct Header), 0, (struct sockaddr*)&dest_addr, &addrlen); + if(recvb != resplen) + fprintf(stderr, "expected length %d got %d", recvb, resplen); + + // check header crc + uint8_t expected_crc8 = crc8(resp, 3); + if(resp->header.crc != expected_crc8) + fprintf(stderr, "expected crc8 %d got %d", resp->header.crc, expected_crc8); + + // check footer crc + uint16_t expected_crc16 = crc16(recvbuff, recvb - 2); + uint16_t actual_crc16 = ntohs(*(uint16_t*)(recvbuff + recvb - 2)); + if(actual_crc16 != expected_crc16) + fprintf(stderr, "expected crc16 %d got %d", actual_crc16, expected_crc16); + + // check hostbyte + if(resp->header.receiver != session->hostbyte) + fprintf(stderr, "expected receiver %d got %d", session->hostbyte, resp->header.receiver); return 0; }