用SELinux加强网络安全

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define PORT 3490 // the port client will be connecting to 

#define MAXDATASIZE 100 // max number of bytes we can get at once 

int main(int argc, char *argv[])
{
int sockfd, numbytes;  
char buf[MAXDATASIZE];
struct hostent *he;
struct sockaddr_in their_addr; // connector's address information 
security_context_t con = NULL;

if (argc != 2) {
fprintf(stderr,"usage: client hostname\n");
exit(1);
}

if ((he=gethostbyname(argv[1])) == NULL) {  // get the host info 
herror("gethostbyname");
exit(1);
}

if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
perror("socket");
exit(1);
}

their_addr.sin_family = AF_INET;    // host byte order 
their_addr.sin_port = htons(PORT);  // short, network byte order 
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
memset(&(their_addr.sin_zero), '\0', 8);  // zero the rest of the struct 

if (connect(sockfd, (struct sockaddr *)&their_addr,
sizeof(struct sockaddr)) == -1) {
perror("connect");
exit(1);
}

if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
perror("recv");
exit(1);
}

if (getpeercon(sockfd, &con)) {
perror("getpeercon");
}

buf[numbytes] = '\0';

printf("Received: %s from %s\n",buf, con);

close(sockfd);

return 0;
}