CS460-Projects/echoserver/echoserver.c

// header files
#include "echoserver.h"

// constants
// echoserver port is 8888
#define ECHOPORT 8888
#define BUFFER_SIZE 1024
#define MAX_CONNECT_QUEUE 10

// prototypes

// main function
int main(int argc, char **argv)
{
    // initialize program (variables and structs)
    bool quitFlag = true;
    int socketEchoFD;
    int clientEchoFD;
    int reuseAddrOpt = 1;
    int keepAliveOpt = 1;
    char message[BUFFER_SIZE];
    int messageBytes;
    struct sockaddr_in serverAddr;
    struct sockaddr_storage clientAddr;
    socklen_t clientSize;
    memset(&serverAddr, 0, sizeof(serverAddr));
    memset(&clientAddr, 0, sizeof(clientAddr));
    // define a TCP socket
    socketEchoFD = socket(AF_INET, SOCK_STREAM, 0);
    if(socketEchoFD < 0)
    {
        printf("Unable to create the socket.\n");
        return -1;
    }
    // use the setsockopt function to make the socket accept different configurations
    // allow for the reuse of the address/bind.
    setsockopt(socketEchoFD, SOL_SOCKET, SO_REUSEADDR, &reuseAddrOpt, sizeof(reuseAddrOpt));
    // also need to set the socket to keepalive using setsockopt
    setsockopt(socketEchoFD, SOL_SOCKET, SO_KEEPALIVE, &keepAliveOpt, sizeof(keepAliveOpt));
    // CODE HERE
    // bind the TCP socket to port 8888 / ECHOPORT
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_addr.s_addr = INADDR_ANY;
    serverAddr.sin_port = htons(ECHOPORT);
    int bindCheck = bind(socketEchoFD, &serverAddr, sizeof(serverAddr));
    if(bindCheck < 0)
    {
        printf("Unable to bind the socket to the port or address.\n Is either in use?");
        return -1;
    }
    // the server will now accept client connections by listening.
    listen(socketEchoFD, MAX_CONNECT_QUEUE);
    // while loop that will continue to listen for messages from clients.
    printf("Echoserver listening on port: %d\n", ECHOPORT);
    // while(quitFlag)
    // {
    //     int clientAddrLen;
    //     int receivedDataLen;
    //     // grab the data from the client
    //     receivedDataLen = recvfrom(socketEchoFD, message, BUFFER_SIZE, MSG_WAITALL, &clientAddr, &clientAddrLen);
    //     message[receivedDataLen] = '\0';
    //     // if "01189998811991197253\r\n" is received, then close the server.
    //     if(strcmp(message, "01189998811991197253\n") == 0 || strcmp(message, "01189998811991197253\r\n") == 0)
    //     {
    //         // if the server recv'd the close command, then close the server.
    //         printf("\nServer received close.\n");
    //         quitFlag = false;
    //     }
    //     // otherwise, repeat/echo back the message to the client.
    //     // setup the reply message
    //     char reply[BUFFER_SIZE];
    //     // add the current time to the reply
    //     sprintf(reply, "%d", time(NULL));
    //     // send the reply to the requestee
    //     sendto(socketEchoFD, (const char *)reply, strlen(reply), 0, (const struct sockaddr *)&clientAddr, clientAddrLen);
    //     // log the time command recv'd
    //     printf("\nServer received time. Replied with: %d\n", time(NULL));
    // }
    while (quitFlag)
    {
        // grab the size of the listened clients
        clientSize = sizeof(clientAddr);
        // grab the client's socket information
        clientEchoFD = accept(socketEchoFD, &clientAddr, &clientSize);
        // check to see if the client socket is actually connected
        if(clientEchoFD == -1)
        {
            printf("\nUnable to accept from the client.\n");
            return -1;
        }
        else
        {
            printf("\nConnection received from client.\n");
        }
        // grab the data from the client, save to message.
        messageBytes = recv(clientEchoFD, message, BUFFER_SIZE, 0);
        // if "01189998811991197253\r\n" is received, then close the server.
        if (strcmp(message, "01189998811991197253\n") == 0 || strcmp(message, "01189998811991197253\r\n") == 0)
        {
            // if the server recv'd the close command, then close the server.
            printf("\nServer received close.\n");
            quitFlag = false;
        }
        // otherwise, repeat/echo back the message to the client.
        // NEW CODE HERE
        // make sure that the connection is still open before attempting to send.
        if(messageBytes <= 0)
        {
            printf("\nERROR\n");
            // this means that the connection is closed, or had another error.
            return -1;
        }
        else
        {
            // send back the message over the clientEcho socket.
            send(clientEchoFD, message, sizeof(message), 0);
            printf("\nMessage has been sent back to client.\n");
        }
        // close the accepted listening socket since it is no longer needed.
        close(clientEchoFD);
    }
    // close the socket
    close(socketEchoFD);
    // profit???
    return 0;
}

// function definitions

/*
Name: ???
Process: ???
Function Input/Parameters: ???
Function Output/Parameters: ???
Function Output/Returned: ???
Device Input/Device: ???
Device Output/Device: ???
Dependencies: ???
*/