addrule.c

Linux下server与client的通信实现。Server支持多线程。附有makefile可供编译。Linux下调试通过。

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

void error(char *msg)
{
    perror(msg);
    exit(0);
}

int main(int argc, char *argv[])
{
    int sockfd, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;
    char *position;
    int count, tmp;
    int portno;
    char *endptr;

    if (argc < 3) {
      fprintf (stderr, "usage: %s hostname port configuration line \n", argv[0]);
      exit (1);
    }
    
    portno = strtol (argv[2],  &endptr, 10);
    if ((portno == 0 ) || (endptr == NULL) || (*endptr != '\0')) {
      fprintf (stderr, "%s: invalid port number!\n", argv[0]);
      exit (1);
    }

    char buffer[BUFFERLENGTH];
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
        error("ERROR opening socket");
    server = gethostbyname(argv[1]);
    if (server == NULL) {
        fprintf(stderr,"ERROR, no such host\n");
        exit(0);
    }
    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("ERROR connecting");

    /* Now fill the buffer with the arguments */
    
    bzero(buffer,BUFFERLENGTH);
    position = buffer;
    /* skip program name */
    argc = argc - 3;
    argv += 3;

    /* put command in first character */
    buffer[0] = ADD_RULE;
    count = BUFFERLENGTH - 2;
    position = buffer + 1;
    
    while (argc) {
      tmp = strlen (*argv);
      if (tmp > count) {
	fprintf (stderr, "Maximal string length exceeded!\n");
	exit (1);
      }
      position = memcpy (position, *argv, tmp);
      position += tmp;
      
      argc --;
      argv ++;
      
      count = count - tmp;
    }
    
    /* add the final null character */
    *position = '\0';
    position++;

    printf ("Writing data to socket: %s\n", buffer);
    n = write (sockfd, buffer, position - buffer);
    if (n < 0) 
         error("ERROR writing to socket");
    bzero (buffer, BUFFERLENGTH);

    /* wait for reply */
    n = read (sockfd, buffer, BUFFERLENGTH -1);
    if (n < 0) 
         error("ERROR reading from socket");
    
    switch (buffer[0]) {
    case ILLEGAL_IP_ADDRESS:
      printf ("Illegal IP-address \n");
      exit (1);
    case ILLEGAL_UID:
      printf ("Illegal user name \n");
      exit (1);
    case ILLEGAL_PORT:  
      printf ("Illegal port name \n");
      exit (1);
    case ILLEGAL_PROGRAM:  
      printf ("Illegal program \n");
      exit (1);
    case OK:
      break;
    default:
      error ("Illegal return value from server!");
    }
    /*     printf ("Rule successfully added \n");*/
    return 0;
}