#include <stdio.h>
#include <memory.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <openssl/crypto.h>
#include <openssl/x509.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#define CHK_NULL(x) if ((x)==NULL) exit (1)
#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }
#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }
void main ()
{
int err;
int sd;
struct sockaddr_in sa;
SSL_CTX* ctx;
SSL* ssl;
X509* server_cert;
char* str;
char buf [4096];
SSL_METHOD *meth;
SSLeay_add_ssl_algorithms();
meth = SSLv2_client_method();
SSL_load_error_strings();
ctx = SSL_CTX_new (meth); CHK_NULL(ctx);
CHK_SSL(err);
sd = socket (AF_INET, SOCK_STREAM, 0); CHK_ERR(sd, "socket");
memset (&sa, '\0', sizeof(sa));
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = inet_addr ("127.0.0.1");
sa.sin_port = htons (1111);
err = connect(sd, (struct sockaddr*) &sa,
sizeof(sa)); CHK_ERR(err, "connect");
ssl = SSL_new (ctx); CHK_NULL(ssl);
SSL_set_fd (ssl, sd);
err = SSL_connect (ssl); CHK_SSL(err);
printf ("SSL connection using %s\n", SSL_get_cipher (ssl));
server_cert = SSL_get_peer_certificate (ssl); CHK_NULL(server_cert);
printf ("Server certificate:\n");
str = X509_NAME_oneline (X509_get_subject_name (server_cert),0,0);
CHK_NULL(str);
printf ("\t subject: %s\n", str);
Free (str);
str = X509_NAME_oneline (X509_get_issuer_name (server_cert),0,0);
CHK_NULL(str);
printf ("\t issuer: %s\n", str);
Free (str);
X509_free (server_cert);
err = SSL_write (ssl, "Hello World!", strlen("Hello World!")); CHK_SSL(err);
err = SSL_read (ssl, buf, sizeof(buf) - 1); CHK_SSL(err);
buf[err] = '\0';
printf ("Got %d chars:'%s'\n", err, buf);
SSL_shutdown (ssl);
close (sd);
SSL_free (ssl);
SSL_CTX_free (ctx);
}