OpenSSL库应用的一个例子

/*  ssl_sockets.c  */

// This code is provided "as is" with NO WARRANTY expressed or
// implied. You may use it freely at your own risk.

#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <openssl/ssl.h>
#include <assert.h>

void die(const char *ptr){
        assert(ptr);
        puts(ptr);
        exit(-1);
}

int writeToSSLSocket(SSL *ssl, char *request) {
   int bytesWritten;

   bytesWritten = SSL_write (ssl, request, strlen(request));
   return bytesWritten;
}

int readn(SSL *ssl, char *buf,int n) {
   unsigned char *p;
   int i;
   int nread;

   p = (unsigned char *)buf;
   i = 0;
   while(i < n) {
      nread = SSL_read(ssl, p, n-i);
      if(nread <= 0) return(i);
      p += nread;
      i += nread;
   }
   return(i);
}

void printSSLServerResponse(SSL *ssl) {
   int bytesRead;
   int readSize = 4096;
   char buf[readSize + 2];

   memset (buf, 0, sizeof(buf));
   while (bytesRead = readn(ssl, buf, readSize)) {
      printf(buf);
      memset (buf, 0, sizeof(buf));
   }
}

int openSocket(char *host, int port) {
   long ipAddress;
   struct hostent* hostInfo;
   struct sockaddr_in sockInfo;
   int sock;

   memset(&sockInfo, 0, sizeof(sockInfo));
   sockInfo.sin_family = AF_INET;
   sockInfo.sin_port = htons(port);
   ipAddress = inet_addr(host);
   if (ipAddress < 0) {
      hostInfo = gethostbyname(host);
      ipAddress = *(long *)*hostInfo->h_addr_list;
   }
   sockInfo.sin_addr.s_addr = ipAddress;

   // Open the socket
   if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
      die("Can't open socket\n");

   // And connect
   if (connect (sock, (struct sockaddr*)&sockInfo, sizeof(sockInfo)) == -1)
      die("Cannot connect to socket\n");

   return sock;
}

int SSLsocket(SSL *ssl, char *host, int port) {
   int sock, result;

   sock = openSocket(host, port);
   SSL_set_fd(ssl, sock);
   result = SSL_connect(ssl);
   return result;
}