#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/wait.h>
#include <pthread.h>


#define PPPD_PATH "/usr/sbin/pppd"


void printbuf(unsigned char *buf, int cnt)
{
    int i;
    for (i = 0; i < cnt; i++)
    {
        printf("0x%02X ", (unsigned)buf[i]);
    }
}

typedef void * pvoid;


void * piperead(void *arg)
{
    pvoid *inf = arg;
    char* buf       = (char*)(inf[0]);
    int*  p_conn_s      = (int*)(inf[1]);
    int*  writepipe     = (int*)(inf[2]);
    int*  readpipe      = (int*)(inf[3]);
    int conn_s = *p_conn_s;

    printf("piperead\n");

    while (1)
    {
        int cnt;
        cnt = read(writepipe[0], buf, 1024);
        if (cnt > 0)
        {
            send(conn_s, buf, cnt, MSG_DONTWAIT);
            printf("send %i\n", cnt);
        }
    }



    return NULL;
}

void * pipewrite(void *arg)
{
    pvoid *inf = arg;
    char* buf       = (char*)(inf[0]);
    int*  p_conn_s      = (int*)(inf[1]);
    int*  writepipe     = (int*)(inf[2]);
    int*  readpipe      = (int*)(inf[3]);

    int conn_s = *p_conn_s;

    printf("pipewrite\n");
    while (1)
    {
        int cnt;

        cnt = recv(conn_s, buf, 1024, 0);
        if (cnt > 0)
        {
            printf("Receive %i: ", cnt);
            printbuf(buf, cnt);
            printf("\n");
            write(readpipe[1], buf, cnt);
        }
    }


    return NULL;
}



int main(int argc, char **argv)
{
    char *server = NULL;
    char *mode;
    int srv;


    int port, conn_s;
    struct sockaddr_in serv_addr, client_addr;
    int cliaddr;



    int readpipe[2], writepipe[2];

    unsigned char buf[1024];

    int ret=0;

    if (argc == 1)
    {
        printf("no arguments!\n");
        return 0;
    }
    mode = argv[1];

    if (strcmp(mode, "server")==0)
    {
        srv = 1;
    }
    else if (strcmp(mode, "client") == 0)
    {
        srv = 0;
    }
    else
    {
        printf("wrong argument!\n");
        return 0;
    }

    pipe(readpipe);
    pipe(writepipe);



    port=socket(AF_INET, SOCK_STREAM, 0);


    if (srv == 0)
    {
        int portn;
        port=socket(AF_INET, SOCK_STREAM, 0);
        sscanf(argv[3], "%i", &portn);


            serv_addr.sin_family = AF_INET;
            serv_addr.sin_addr.s_addr = inet_addr(argv[2]);
        serv_addr.sin_port = htons(portn);
        printf("connecting %s\n", argv[2]);
            ret = connect(port, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
            if (ret < 0)
            {
                    printf("server not found\n");
                    return (0);
            }
        conn_s = port;
    }
    else
    {
        int portn;
        sscanf(argv[2], "%i", &portn);
        serv_addr.sin_family = AF_INET;
            serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
            serv_addr.sin_port = htons(portn);

            bind(port, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
            listen(port, 1024);
        conn_s = accept(port, NULL, NULL);
                printf("Accepted!\n");
    }
    ret = fork();
    if (ret < 0)
    {
        printf("fork failed!\n");
        return 0;
    }
    else if (ret == 0)
    {

        printf("PPP\n");
        dup2(readpipe[0], 0);
        dup2(writepipe[1], 1);

        close(readpipe[0]);
        close(readpipe[1]);
        close(writepipe[0]);
        close(writepipe[1]);

        if (srv == 0)
        {
            execl(PPPD_PATH, "updetach", "notty", "noauth", NULL);
        }
        else
        {
            execl(PPPD_PATH, "nodetach", "notty", "noauth", "persist", "passive", NULL);
        }


    }
    else
    {
        int code;
        pvoid inf[4];
        pthread_t tr, tw;


        printf("PPP id = %i\n", ret);

        inf[0] = (pvoid)buf;
        inf[1] = (pvoid)&conn_s;
        inf[2] = (pvoid)writepipe;
        inf[3] = (pvoid)readpipe;


        pthread_create(&tr, NULL, piperead, (pvoid)inf);
        pthread_create(&tw, NULL, pipewrite, (pvoid)inf);


        wait(&code);
        printf("PARENT: Код возврата PPPD:%d\n", WEXITSTATUS(code));

    }
    return 0;
}