Add openssl c langage library on windows - c

Question

I'm producing my 1st projet in c. I want to build a mail client.
I used the socket to do it.
But have some trouble with that methode. I can't send a mail with a gmail smtp server because of an encoding protocol.
So after some research, i understood that i haven't lot's of choice. I have to use the openssl library.
And that's the problem. I understood how to use that library (I hope, you can judge it with my code attached) but i never understand how to add the library.
On stackoverflow i find solutions for linux and android so i create a new post.
So that's my question:
What should I do with the zip file that i download from openssl official website?. And even which zip file do I need to download ?
SOCKET connexion(char* server_name,unsigned short port)
{
char buf[1024]={0};
int res_l= 0;
int nbrecv;
struct sockaddr_in serverSockAddr;
struct hostent * serverHostEnt;
SOCKET to_server_socket = 0;
memset(&serverSockAddr,0, sizeof(serverSockAddr) );
serverHostEnt = gethostbyname( server_name );
if ( serverHostEnt == NULL )
{
res_l = h_errno;
return (SOCKET)-1;
}
memcpy(&serverSockAddr.sin_addr,serverHostEnt->h_addr, serverHostEnt->h_length );
serverSockAddr.sin_port = htons( port );
serverSockAddr.sin_family = AF_INET;
to_server_socket = socket( AF_INET, SOCK_STREAM, 0 );
if( connect( to_server_socket, ( struct sockaddr * ) &serverSockAddr,sizeof( serverSockAddr ) ) < 0 ) return (SOCKET)-3;
while( !buf[0] ) nbrecv = recv( to_server_socket, buf, 1024, 0 );
printf("Welcome message : %s\n",buf);
return to_server_socket;
}
void SendAndReceiveSSL(SSL * ssl, char * messagesend, int n){
{
char bufreceive[1024];
int size,retVal,nbrecv;
size = (int)strlen( messagesend );
retVal = SSL_write( ssl, messagesend, size);
printf("Envoye : %s\n",messagesend) ;
memset(bufreceive,0,1024);
if (n!=1) //n=0 if i don't want an answer of the server.
{
while(!bufreceive[0]) nbrecv = SSL_read( ssl, bufreceive,1024);
printf("Recu : %s\n",bufreceive);
}
}
int mail_ssl(SOCKET sock, SSL ssl, const char* from,const char* to,const char* body)
{
#define SIZEMAX 1000
char buffer[SIZEMAX]; int n=0;
SendAndReceive(sock, "EHLO localhost\r\n",n); //no ssl for the 2 1st sentences//EHLO localhose ... wait 250
SendAndReceive(sock, "STARTTLS\r\n,n)
SendAndReceiveSSL(ssl, "EHLO localhost\r\n",n); //sll for the next
sprintf(buffer,"MAIL FROM: <%s>\r\n",from);
SendAndReceiveSSL(ssl, buffer,n); //MAIL FROM:<******> wait 250
sprintf(buffer,"RCPT TO: <%s>\r\n",to);
SendAndReceiveSSL(ssl, buffer,n); //RCPT TO:<******> wait 250
SendAndReceiveSSL(ssl, "DATA\r\n",n); //DATA wait 340
sprintf(buffer, "Subject: %s\r\n",body); n=1;
SendAndReceiveSSL(ssl, buffer,n); n=0; //Subject : subject \r\n body\r\n ///// DON'T WAIT
SendAndReceiveSSL(ssl, ".\r\n",n); //.\r\n wait 250
SendAndReceiveSSL(ssl, "QUIT\r\n",n);
return 0;
}
SSL_CTX* InitCTX(void)
{
SSL_METHOD *method;
SSL_CTX *ctx;
OpenSSL_add_all_algorithms(); // Load cryptos, et.al.
SSL_load_error_strings(); // Bring in and register error messages
method = TLSv1_2_client_method(); // Create new client-method instance
ctx = SSL_CTX_new(method); // Create new context
if ( ctx == NULL )
{
ERR_print_errors_fp(stderr);
abort();
}
return ctx;
}
void ShowCerts(SSL* ssl)
{
X509 *cert;
char *line;
cert = SSL_get_peer_certificate(ssl); // get the server's certificate
if ( cert != NULL )
{
printf("Server certificates:\n");
line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
printf("Subject: %s\n", line);
free(line); // free the malloc'ed string
line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
printf("Issuer: %s\n", line);
free(line); // free the malloc'ed string
X509_free(cert); // free the malloc'ed certificate copy
}
else printf("Info: No client certificates configured.\n");
}
int authSSL(SOCKET sock, const char* from,const char* to,const char* body)
{
SSL_CTX *ctx;
SSL *ssl;
SSL_library_init();
ctx = InitCTX();
ssl = SSL_new(ctx);
SSL_set_fd(ssl, sock);
if ( SSL_connect(ssl) == FAIL )
ERR_print_errors_fp(stderr);
else
{
printf("Connected with %s encryption\n", SSL_get_cipher(ssl));
ShowCerts(ssl);
SSL_write(ssl, msg, strlen(msg));
mail_ssl(sock, ssl, from, to, body); //In this function i collect
//all the informations to create the mail and i use all the function above
SSL_free(ssl);
}
close(server); // close socket
SSL_CTX_free(ctx); // release context
return 0;
}

Answer 1

you can use VCPKG package manager, it will download and configure your envirument if you are using Visual Studio