Colony

/* SERVER

I am washing my socks.

And hanging them out to dry.

-Greg

*/

#include <sys/types.h>

#include <sys/socket.h>

#include <stdio.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <string.h>

#include <netdb.h>

int mysocket;   //the socket that gets new connections

int io_socket;  //the socket we use to communicate when a connection is initiated.

int main (int argc, char **argv) {

        unsigned int clientlen;

        struct sockaddr_in clientaddr;

        struct hostent *hp;

        char *haddrp;

        char newdata[100];

        int newdatasize;

        if (argc != 2) {

                fprintf(stderr, "Usage: %s <port>\n", argv[0]);

                return 0;

        }

        //start server

        printf("Starting server on port %i\n", atoi(argv[1]));

        mysocket = open_listenfd(atoi(argv[1]));

        if (mysocket < 0) {

                fprintf(stderr, "Error listening on port.\n");

                return -1;

        } else {

                printf("Server running, waiting for connection\n");

        }

        //accept connections

        while (1) {

                clientlen = sizeof(clientaddr);

                io_socket = accept(mysocket, (struct sockaddr *) &clientaddr, &clientlen);

                //get client info

                hp = gethostbyaddr((const char *) &clientaddr.sin_addr.s_addr, sizeof(clientaddr.sin_addr.s_addr), AF_INET);

                haddrp = inet_ntoa(clientaddr.sin_addr);

                printf("Client connected: %s %s\n", hp->h_name, haddrp);

                if (!fork()) { // this is the child process

            close(mysocket); // child doesn't need the listener

                        newdata[0] = ' ';

                        while (newdata[0] != 'q') {

                                memset(newdata, '\0', strlen(newdata));

                                newdatasize = recv(io_socket, newdata, 99, 0);

                                printf("Received: %s\n", newdata);

                                //send_command(cmd0, GLOBAL_DEST);

                        }

                        printf("\nClient has disconnected.\n");

            close(io_socket);

            return 0;

        }

                close(io_socket);

        }

        close(mysocket);

        return 0;

}

//listen on port, as specified by 15-213 book.

int open_listenfd(int port) {

        int listenfd, optval=1;

        struct sockaddr_in serveraddr;

        //create socket descriptor

        if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)

                return -1;

        //prevent "address already in use" error

        if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, (const void *) &optval, sizeof(int)) < 0)

                return -1;

        bzero((char *) &serveraddr, sizeof(serveraddr));

        serveraddr.sin_family = AF_INET;

        serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);

        serveraddr.sin_port = htons((unsigned short)port);

        if (bind(listenfd, (struct sockaddr *) &serveraddr, sizeof(serveraddr)) < 0)

                return -1;

        //start listening

        if (listen(listenfd, 128) < 0)

                return -1;

        return listenfd;

}