/* cli.cpp  -  Minimal ssleay client for Unix   30.9.1996, Sampo Kellomaki <sampo@iki.fi> *//* mangled to work with SSLeay-0.9.0b and OpenSSL 0.9.2b   Simplified to be even more minimal   12/98 - 4/99 Wade Scholine <wades@mail.cybg.com> */#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);    /* ----------------------------------------------- */  /* Create a socket and connect to server using normal socket calls. */    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");   /* Server IP */  sa.sin_port        = htons     (1111);          /* Server Port number */    err = connect(sd, (struct sockaddr*) &sa,		sizeof(sa));                   CHK_ERR(err, "connect");  /* ----------------------------------------------- */  /* Now we have TCP conncetion. Start SSL negotiation. */    ssl = SSL_new (ctx);                         CHK_NULL(ssl);      SSL_set_fd (ssl, sd);  err = SSL_connect (ssl);                     CHK_SSL(err);      /* Following two steps are optional and not required for     data exchange to be successful. */    /* Get the cipher - opt */  printf ("SSL connection using %s\n", SSL_get_cipher (ssl));    /* Get server's certificate (note: beware of dynamic allocation) - opt */  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);  OPENSSL_free (str);  str = X509_NAME_oneline (X509_get_issuer_name  (server_cert),0,0);  CHK_NULL(str);  printf ("\t issuer: %s\n", str);  OPENSSL_free (str);  /* We could do all sorts of certificate verification stuff here before     deallocating the certificate. */  X509_free (server_cert);    /* --------------------------------------------------- */  /* DATA EXCHANGE - Send a message and receive a reply. */  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);  /* send SSL/TLS close_notify */  /* Clean up. */  close (sd);  SSL_free (ssl);  SSL_CTX_free (ctx);}/* EOF - cli.cpp */