/**
* \brief Blocking receive of an IR transmission, with optional timeout
* \param buf The buffer in which to place the received data
* \param timeout The time to wait before returning
* \param startstop Whether to remove start/stop bits from transmission
* \return The length of the buffer in bytes.
*
* Receive a message if it's there to be received. Otherwise wait for a time
* that depends on the timeout value: if this is zero (as it is by default),
* then wait forever, else set a timer. If the timer expires return a negative
* number (-1), else return the length of the buffer received. The timeout is
* considered not to have expired if, by the time the period is passed, a
* message has *started* to arrive.
*
* The first received bit is placed in the MSB, meaning that if there is not
* a complete byte's worth of data, the lowest bits will be zero.
*
* Note: Differentiating between a mark and a space is based on a hardwired
* test of length.
*
*/
int EngduinoIRClass::recv(uint8_t *buf, uint16_t timeout, bool startstop)
{
static uint16_t raw[RAWBUFSZ];
uint8_t b = 0; // The byte we're building
uint8_t l = 0; // length of the buffer we've built
int len = recvRaw(raw, timeout);
if (len < 0)
return len;
if (startstop)
len = len - 1; // Remove the stop bit.
// The start bit isn't represented directly - it starts the timer.
for (int i = 0; i < len; i++) {
if (raw[i] < MARKSPACESPLIT) {
// It's a mark.
// Shift in the appropriate one
//
b |= (1 << (i%8));
}
if ((i+1)%8 == 0) {
buf[l++] = b;
b = 0;
}
}
// If there's anything left, add it to the
// list
if ((len % 8) != 0) {
buf[l++] = b;
}
return l;
}
// Main
int main(int argc, char **argv)
{
// ----------- Variable
char recv_packet[BUFF_SIZE+40];
struct iphdr * ip_header = (struct iphdr *) recv_packet;
struct tcphdr * tcp_header = 0;
// ----------- Start
printf("\nStart Deflector\n\n");
// ----------- Raw Socket
printf("Create Raw Socket(Receive)\n");
int recv_socket = socketRaw(IPPROTO_TCP, DEFLECTOR_PORT);
// ----------- UDP
printf("Create UDP Socket(Send)\n");
int send_socket = socket( PF_INET, SOCK_DGRAM, 0 );
struct sockaddr_in bypass_addr;
memset( &bypass_addr, 0, sizeof(bypass_addr) );
bypass_addr.sin_family = AF_INET;
bypass_addr.sin_port = htons(BYPASS_PORT);
bypass_addr.sin_addr.s_addr = inet_addr(BYPASS_ADDR);
// ----------- Main Loop
printf("Enter Main Loop\n");
while(1)
{
recvRaw( recv_socket, recv_packet, sizeof(recv_packet) );
tcp_header = (struct tcphdr *) (recv_packet + ip_header->ihl * 4);
if ( ntohs( tcp_header->dest ) == DEFLECTOR_PORT )
{
tcp_header = (struct tcphdr *) (recv_packet + ip_header->ihl * 4);
tcp_header->check = 0;
tcp_header->check = tcp_checksum(ip_header, tcp_header);
ip_header->check = 0;
ip_header->check = checksum2((unsigned short*)ip_header, sizeof(struct iphdr));
// ----------- Receive Packet
printf("\nReceive Packet\n");
#ifdef DEBUG_DEFLECTOR
printf("----------------------------------------\n");
printf( "[ 패킷을 받았습니다. ]\n" );
printf( "발신자 IP : %s\n", inet_ntoa( * (struct in_addr*) &ip_header->saddr) );
printf( "발신자 Port : %5u\n", ntohs(tcp_header->source) );
printf( "수신자 IP : %s\n", inet_ntoa( * (struct in_addr*) &ip_header->daddr) );
printf( "수신자 Port : %5u\n", ntohs(tcp_header->dest) );
printf( "IP packet size : %d\n", ntohs(ip_header->tot_len));
printf( "IP check : %d\n", ip_header->check );
printf( "IP Version : %d\n", ip_header->version ); // IP 버전 정보 출력
printf( "Time To Live : %d\n", ip_header->ttl ); // TTL 정보 출력
printf( "TCP check : %d\n", tcp_header->check );
printf( "Window Size : %d\n", tcp_header->window ); // 윈도우 사이즈 정보 출력
printf( "Flags : " ); // 플래그 정보 출력
if( tcp_header->fin == 1 ) printf( "[FIN]\n" );
if( tcp_header->syn == 1 ) printf( "[SYN]\n" );
if( tcp_header->rst == 1 ) printf( "[RST]\n" );
if( tcp_header->psh == 1 ) printf( "[PSH]\n" );
if( tcp_header->ack == 1 ) printf( "[ACK]\n" );
if( tcp_header->urg == 1 ) printf( "[URG]\n" );
printf("-----------------------------------------\n");
#endif
// ----------- Send UDP Packet
printf("Send UDP Packet\n");
sendto( send_socket, (void *) &recv_packet, sizeof(recv_packet)+1, 0, (struct sockaddr *) &bypass_addr, sizeof(bypass_addr) );
}
}
}
