git.sesse.net Git - ultimatescore/blob - client/bodet.cpp

   1 // Bodet BT-6000 decoder.
   2
   3 #include <fcntl.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <termios.h>
   7 #include <unistd.h>
   8
   9 #include <string>
  10 #include <vector>
  11
  12 #include <arpa/inet.h>
  13 #include <netinet/in.h>
  14 #include <netinet/tcp.h>
  15 #include <stdlib.h>
  16 #include <sys/types.h>
  17 #include <sys/socket.h>
  18
  19 using namespace std;
  20
  21 int sock;
  22 sockaddr_in6 saddr6;
  23
  24 void process(const string &buf)
  25 {
  26         unsigned char checksum = 0;
  27         for (size_t i = 1; i <= buf.size() - 2; ++i) {
  28                 checksum ^= buf[i];
  29         }
  30         checksum &= 0x7f;
  31         if (checksum < 0x20) {
  32                 checksum += 0x20;
  33         }
  34         if (checksum != buf.back()) {
  35         //      fprintf(stderr, "discarding message with broken checksum: [%s] [%x vs. %x]\n", buf.c_str(), checksum, buf.back());
  36         } else {
  37                 string realmsg = buf.substr(3, buf.size() - 5);
  38                 sendto(sock, realmsg.data(), realmsg.size(), 0, (sockaddr *)&saddr6, sizeof(saddr6));
  39         }
  40 }
  41
  42 int main(int argc, char **argv)
  43 {
  44         sock = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
  45         if (sock == -1) {
  46                 perror("socket");
  47                 exit(1);
  48         }
  49
  50         int one = 1;
  51         if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) == -1) {
  52                 perror("setsockopt");
  53                 exit(1);
  54         }
  55
  56         memset(&saddr6, 0, sizeof(saddr6));
  57         saddr6.sin6_family = AF_INET6;
  58         if (argc >= 2) {
  59                 if (inet_pton(AF_INET6, argv[1], &saddr6.sin6_addr) != 1) {
  60                         fprintf(stderr, "Invalid address '%s'\n", argv[1]);
  61                         exit(1);
  62                 }
  63         } else {
  64                 inet_pton(AF_INET6, "::1", &saddr6.sin6_addr);
  65         }
  66
  67         int port = 6000;
  68         if (argc >= 3) {
  69                 port = atoi(argv[2]);
  70         }
  71         saddr6.sin6_port = htons(port);
  72
  73         const char *serialpath = "/dev/ttyUSB0";
  74         if (argc >= 4) {
  75                 serialpath = argv[3];
  76         }
  77         int serialfd = open(serialpath, O_RDWR);
  78         if (serialfd == -1) {
  79                 perror(serialpath);
  80                 exit(1);
  81         }
  82
  83         struct termios options;
  84         memset(&options, 0, sizeof(options));
  85         options.c_cflag = B9600 | CS8 | CLOCAL | CREAD;
  86         options.c_iflag = IGNBRK | IGNPAR;
  87         options.c_lflag = 0;
  88         options.c_cc[VMIN] = 1;  // Blocking read, minimum one byte.
  89         tcsetattr(serialfd, TCSANOW, &options);
  90
  91         string buf;
  92
  93         for ( ;; ) {
  94                 char ch;
  95                 int ret = read(serialfd, &ch, 1);
  96                 if (ret == -1) {
  97                         perror("read");
  98                         exit(1);
  99                 }
 100                 if (ret == 0) {
 101                         fprintf(stderr, "short read\n");
 102                         exit(1);
 103                 }
 104
 105                 putchar(ch);
 106                 fflush(stdout);
 107                 if (ch == 1) {  // SOH
 108                         buf = ch;
 109                         continue;
 110                 }
 111                 if (buf.size() == 1) {
 112                         // Address
 113                         buf.push_back(ch);
 114                         continue;
 115                 }
 116                 if (ch == 2) {  // STX
 117                         if (buf.size() == 2) {
 118                                 buf.push_back(ch);
 119                         } else {
 120                                 buf.clear();  // STX out-of-order
 121                         }
 122                         continue;
 123                 }
 124
 125                 if (!buf.empty() && buf.back() == 3) {  // Last was ETX, so this is LTC.
 126                         buf.push_back(ch);
 127                         process(buf);
 128                         buf.clear();
 129                         continue;
 130                 }
 131
 132                 if (ch == 3) {  // ETX
 133                         if (buf.size() >= 4) {
 134                                 buf.push_back(ch);
 135                         } else {
 136                                 buf.clear();  // ETX out-of-order
 137                         }
 138                         continue;
 139                 }
 140                 buf.push_back(ch);
 141         }
 142 }