Creates two FIFO files that are piped to a network connection.

netfifo.c

/*  NetFIFO
 *  Creates two FIFO files that are piped to a network connection.
 *  Made by sfan5
 *  License: CC-BY-SA v3
 * 
 *  Example Usage:
 *    netfifo tcp google.com 80 ififo ofifo &
 *    echo -e "GET / HTTP/1.1 \r\n" > ififo
 *    cat ofifo
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>

#define log(e) { fprintf(stderr, "[NetFIFO] LOG %s\n", e); }
#define warn(e) { fprintf(stderr, "[NetFIFO] WARN %s\n", e); }
#define error(e) { fprintf(stderr, "[NetFIFO] ERR %s\n", e); perror(""); return EXIT_FAILURE; }
#define BUFLEN 256
#define VERSION "0.1"
//#define DEBUG

unsigned short run;

void sigfunc(int sig)
{
    if(sig == SIGINT || sig == SIGTERM)
    {
        run = 0;
    }
}

int main(int argc, char *argv[])
{
    printf("NetFIFO %s\n", VERSION);
    signal(SIGINT, sigfunc);
    signal(SIGTERM, sigfunc);
    if(argc < 5)
    {
       printf("Usage: %s <protocol> <address> <port> <inpipe> <outpipe>\n", argv[0]);
       return EXIT_SUCCESS;
    }

    int sockfd, portno, n, socktype, wfd, rfd;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    char buffer[BUFLEN];

    if(!strcmp(argv[1], "tcp"))
    {
        socktype = SOCK_STREAM;
    }
    else if(!strcmp(argv[1], "udp"))
    {
        socktype = SOCK_DGRAM;
    }
    else error("Unknown protocol");
    portno = atoi(argv[3]);
    sockfd = socket(AF_INET, socktype, 0);
    if(sockfd < 0) error("Could not open socket");
    server = gethostbyname(argv[2]);
    if(!server)
    {
        fprintf(stderr, "%s\n", hstrerror(h_errno));
        error("gethostbyname failed");
    }
    bzero((char*) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char*) server->h_addr, (char*) &serv_addr.sin_addr.s_addr, server->h_length);
    serv_addr.sin_port = htons(portno);
    if(connect(sockfd, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) < 0) error("Could not connect");
    fcntl(sockfd, F_SETFL, O_NONBLOCK);
    log("Connected to Server");
    if(mkfifo(argv[4], S_IRWXU | S_IRWXG) != 0) error("Could not create FIFO");
    if(mkfifo(argv[5], S_IRWXU | S_IRWXG) != 0) error("Could not create FIFO");
    if((rfd = open(argv[4], O_RDONLY | O_NONBLOCK)) < 0) error("Could not open FIFO for reading");
    if((wfd = open(argv[5], O_WRONLY)) < 0) error("Could not open FIFO for writing");
    log("Ready!");
    run = 1;
    while(run)
    {
        bzero(buffer, BUFLEN);
        n = read(rfd, buffer, BUFLEN);
        if(n > 0)
        {
#ifdef DEBUG
            printf(" FIFO -> Socket %d bytes\n", n);
#endif
            n = write(sockfd, buffer, n);
            if(n < 0) warn("Could not write to Socket");
        }
        bzero(buffer, BUFLEN);
        n = read(sockfd, buffer, BUFLEN);
        if(n > 0)
        {
#ifdef DEBUG
            printf(" Socket -> FIFO %d bytes\n", n);
#endif
            n = write(wfd, buffer, n);
            if(n < 0) warn("Could not write to FIFO");
        }
    }
    log("Closing!");
    close(sockfd);
    close(rfd);
    close(wfd);
    unlink(argv[4]);
    unlink(argv[5]);
    return EXIT_SUCCESS;
}