int main(int argc, char** argv){
// Creating required variables for UDP socket
int userChoice;
struct sockaddr_in server_address;
int client_socket;
socklen_t slen = sizeof(server_address);
// Creating buffer for sending/receiving datagrams (512 characters, defined in header)
char buf[BUFLEN];
// Create the socket
if ((client_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1){
perror("Socket error\n");
exit(1);
}
// Set up the address
memset((char *)&server_address, 0, sizeof(server_address));
server_address.sin_family = AF_INET;
server_address.sin_port = htons(PORT);
// Internet address manipulation?
if (inet_aton(SERVER_ADDR, &server_address.sin_addr) == 0){
perror("inet_aton() failed\n");
exit(1);
}
// Keep allowing user to choose, choice of 4 will exit, nice visual menu for easy understanding
while(1){
printf("+-------- C Datagram Client --------+\n");
printf("| 1. Echo Server |\n");
printf("| 2. DNS Lookup service |\n");
printf("| 3. Get server time. |\n");
printf("| 4. Quit |\n");
printf("+-----------------------------------+\n");
printf("What would you like to do: ");
scanf("%d", &userChoice);
if(userChoice == 1) {
// Let user send a message to the server
echoServer(client_socket, server_address, slen);
}
else if(userChoice == 2) {
// Let user get the IP for their requested URL
dnsLookup(client_socket, server_address, slen);
}
else if(userChoice == 3) {
// Get the server time
serverTime(client_socket, server_address, slen);
}
// Exit the client
else if(userChoice == 4) return 0;
// Invalid input/choice
else printf("You must enter 1, 2, 3, or 4.\n\n");
}
}
//Initialize GroveStreams
void GroveStreams::begin(void)
{
int ret = dnsLookup(_serverName, serverIP);
if (ret == 1)
{
Serial << millis() << F(" GroveStreams ") << serverIP << endl;
}
else
{
Serial << millis() << F(" GS DNS lookup fail, ret=") << ret << endl;
mcuReset();
}
ipToText(_localIP, Ethernet.localIP());
ipToText(_groveStreamsIP, serverIP);
}
bool initAddress(SOCKADDR_IN& saddr, const std::string& addr, unsigned short port, bool getByName){
memset(&saddr, 0x00, sizeof(SOCKADDR_IN));
saddr.sin_family = AF_INET;
if(addr.size()==0){
saddr.sin_addr.S_un.S_addr = INADDR_ANY;
}
else{
if(getByName){
if(dnsLookup(addr, &saddr.sin_addr)==false)
return false;
}
else{
saddr.sin_addr.S_un.S_addr = inet_addr(addr.c_str());
}
}
saddr.sin_port = htons(port);
return true;
}
object *socket::connect(string *host, integer *port)
{
if (socket_val < 0)
{
exceptions::SocketError *exc = exceptions::SocketError::Create(
1,
new string("Socket already closed.")
);
exc->throw_exception();
}
if (dnsLookup(host->string_val.c_str(), port->val, 0) < 0)
{
exceptions::SocketError *exc = exceptions::SocketError::Create(
1,
new string("Could not open connection.")
);
exc->throw_exception();
}
return new boolean(true);
}
object *socket::bind(string *host, integer *port)
{
if (socket_val < 0)
{
exceptions::SocketError *exc = exceptions::SocketError::Create(
1,
new string("Socket already closed.")
);
exc->throw_exception();
}
int ret = dnsLookup(host->string_val.c_str(), port->val, 1);
if (ret < 0)
{
exceptions::SocketError *exc = exceptions::SocketError::Create(
1,
new string("Could not look up host.")
);
exc->throw_exception();
}
return new boolean(true);
}
int main( int argc, char** argv) {
// Creating required variables for UDP socket
struct sockaddr_in server_address, client_address;
int server_socket;
ssize_t recv_len;
socklen_t client_address_len = sizeof(client_address);
// Most buffers used will be 512 characters (BUFLEN)
char buf[BUFLEN];
// Store client's choice for each server loop iteration
char choice;
// Create a UDP socket
if ((server_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1){
perror("Error creating socket.");
exit(1);
}
// Zero out the structure
memset((char *) &server_address, 0, sizeof(server_address));
// Setting address
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr = htonl(INADDR_ANY);
server_address.sin_port = htons(PORT);
//bind socket to port
if(bind(server_socket, (struct sockaddr*)&server_address, sizeof(server_address)) == -1){
perror("Error binding socket.");
exit(1);
}
//keep listening for data
while(!0){
// Initially waiting for datagram
printf("Waiting for data...\n\n");
// Clear out the buffer memory for safe usage each time
memset(buf, '\0', sizeof(buf));
//try to recieve some data, this is a blocking call, show error if something goes wrong
if ((recv_len = recvfrom(server_socket, buf, sizeof(buf), 0, (struct sockaddr *)&client_address, &client_address_len)) == -1)
{
perror("Error in recvfrom");
exit(1);
}
// Check for the requested service to send back to client (first char of received message)
// 1 = Echo a message
// 2 = URL to IP lookup
// 3 = Get current time
choice = buf[0];
// Choice 1: Echo
if(choice == '1') {
// For each case, let a function handle what needs to be done
echoMessage(server_socket, client_address, client_address_len);
}
// Choice 2: DNS Lookup
else if(choice == '2') {
// Pass in the socket and address to be able to send datagrams back to client
dnsLookup(server_socket, client_address, client_address_len);
}
// Choice 3: Get current time
else {
getTime(server_socket, client_address, client_address_len);
}
}
close(server_socket);
return 0;
}