server.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。

/* A simple server in the internet domain using TCP
   The port number is passed as an argument */
#include <stdio.h>
#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <firewall.h>
#include <server.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


struct FirewallConfig *firewallTable = NULL; /* global table */


void error(char *msg)
{
    perror(msg);
    exit(1);
}

int main(int argc, char *argv[])
{
     int sockfd, newsockfd, portno;
     socklen_t clilen;
     int errno;
     char buffer[BUFFERLENGTH];
     char result;
     struct sockaddr_in serv_addr, cli_addr;
     int n;
     if (argc < 2) {
         fprintf(stderr,"ERROR, no port provided\n");
         exit(1);
     }
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
     if (sockfd < 0) 
        error("ERROR opening socket");
     bzero((char *) &serv_addr, sizeof(serv_addr));
     portno = atoi(argv[1]);
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr = INADDR_ANY;
     serv_addr.sin_port = htons(portno);
     if (bind(sockfd, (struct sockaddr *) &serv_addr,
              sizeof(serv_addr)) < 0) 
              error("ERROR on binding");
     listen(sockfd,5);
     clilen = sizeof(cli_addr);
     while (1) {
       newsockfd = accept(sockfd, 
			  (struct sockaddr *) &cli_addr, 
			  &clilen);
       if (newsockfd < 0) 
	 error("ERROR on accept");
       bzero(buffer, BUFFERLENGTH);
       n = read(newsockfd,buffer, BUFFERLENGTH -1);
       if (n < 0) 
	 error("ERROR reading from socket");
       switch (buffer[0]) {
       case ADD_RULE:
	 firewallTable = addRule (buffer + 1, firewallTable, &errno);
	 buffer[0] = errno;
	 n  = write (newsockfd, buffer, 1);
	 if (n < 0) 
	   error ("Error writing to socket");
	 break;
       case SHOW_TABLE:
	 showTable (firewallTable);
	 break;
       case CHECK_ENTRY:
	 result = checkEntry (buffer +1, firewallTable, &errno);
	 if (errno != 0) {
	   buffer[0] = errno;
	 }
	 else {
	   buffer[0] = result;
	 }
	 n  = write (newsockfd, buffer, 1);
	 if (n < 0) 
	   error ("Error writing to socket");
	 break;
       default:
	 fprintf (stderr, "Illegal request received: %c\n", buffer[0]);
       }
       close (newsockfd);
     }
     return 0; 
}