initial commit of code from Philip's spaceserver

socket.cpp

@@ -0,0 +1,102 @@
+#include <iostream>
+#include <math.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <fcntl.h>
+#include <sys/time.h>
+#include <thread>
+
+using namespace std;
+
+const int UDP_PORT = 55443; 
+
+sockaddr_in address, dest_address;
+socklen_t destLength = sizeof( dest_address );
+
+double diffclock(timeval clock1,timeval clock2)
+{
+    double diffms = (clock2.tv_sec - clock1.tv_sec) * 1000.0;
+    diffms += (clock2.tv_usec - clock1.tv_usec) / 1000.0;   // us to ms
+    return diffms;
+}
+
+int network_init()
+{
+    //  Create socket 
+    int handle = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    
+    if (handle <= 0) {
+        printf( "failed to create socket\n" );
+        return false;
+    }
+    
+    //  Bind socket to port 
+    address.sin_family = AF_INET;
+    address.sin_addr.s_addr = INADDR_ANY;
+    address.sin_port = htons( (unsigned short) UDP_PORT );
+    
+    if (bind(handle, (const sockaddr*) &address, sizeof(sockaddr_in)) < 0) {
+        printf( "failed to bind socket\n" );
+        return false;
+    }
+    
+    //  Set socket as non-blocking
+    int nonBlocking = 1;
+    if (fcntl( handle, F_SETFL, O_NONBLOCK, nonBlocking ) == -1) {
+        printf( "failed to set non-blocking socket\n" );
+        return false;
+    }
+    
+    dest_address.sin_family = AF_INET;
+    dest_address.sin_addr.s_addr = inet_addr(DESTINATION_IP);
+    dest_address.sin_port = htons( (unsigned short) UDP_PORT );
+        
+    return handle;
+}
+
+int main(int argc, const char * argv[])
+{
+    int received_bytes = 0;
+    timeval time, last_time; 
+    
+    int handle = network_init();
+    
+    if (!handle) {
+        cout << "Failed to create network.\n";
+        return 0;
+    } else {
+        cout << "Network Started.  Waiting for packets.\n";
+    }
+
+    gettimeofday(&last_time, NULL);
+    
+    while (1) {
+        received_bytes = recvfrom(handle, (char*)packet_data, MAX_PACKET_SIZE,
+                                      0, (sockaddr*)&dest_address, &destLength );
+        if (received_bytes > 0) {
+            //std::cout << "Packet from: " << inet_ntoa(dest_address.sin_addr) 
+            //<< " " << packet_data << "\n";
+            float x,y,z;
+            sscanf(packet_data, "%f,%f,%f", &x, &y, &z);
+            if (addAgent(dest_address.sin_addr.s_addr, x, y, z)) {
+                cout << "Added agent from IP: " << 
+                inet_ntoa(dest_address.sin_addr) << "\n";
+            }
+            //  Reply with packet listing nearby active agents
+            send_agent_list(handle, &dest_address);
+        }
+        gettimeofday(&time, NULL);
+        if (diffclock(last_time, time) > LOGOFF_CHECK_INTERVAL) {
+            gettimeofday(&last_time, NULL);
+            update_agent_list(last_time);
+        }
+            
+        usleep(10000);
+    }
+    return 0;
+}
+