Uma amostra de uma conexão SSL com o Google, lendo e escrevendo dados. Desenvolvido por Alexandre Mulatinho <[email protected]> em http://goo.gl/Jvj8cv

ssl_io_google.c

/*
 * ssl-mlt.c
 * Alexandre Mulatinho <[email protected]>
 * Simple framework to HTTPs
 * */
 
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <openssl/rand.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
 
#define BUF_MAX 4096
 
typedef struct {
    int socket;
    char *hostname;
    SSL *ssl;
    SSL_CTX *ssl_ctx;
} conn;
 
int mlt_handle(char *servname)
{
    int ret, soq;
    struct hostent *host;
    struct sockaddr_in server;
 
    host = gethostbyname (servname);
    if ( (soq = socket(AF_INET, SOCK_STREAM, 0)) == -1 ) {
        perror ("Socket");
        return -1;
    }
 
    server.sin_family = AF_INET;
    server.sin_port = htons (443);
    server.sin_addr = *((struct in_addr *) host->h_addr);
 
    if ( ( ret = connect(soq, (struct sockaddr *)&server,
                    sizeof (struct sockaddr)) ) == -1 ) {
       perror ("Connect");
       return -1;
    }
 
    return soq;
}
 
conn *mlt_ssl_connect(char *servname)
{
    conn *p;
 
    p = (conn *)malloc(sizeof(conn));
    p->ssl = NULL;
    p->ssl_ctx = NULL;
    p->hostname = servname;
 
    SSL_load_error_strings ();
    SSL_library_init ();
 
    if ( (p->socket = mlt_handle(p->hostname)) == -1)
        return NULL;
 
    if ( (p->ssl_ctx = SSL_CTX_new(SSLv23_client_method ())) == NULL)
        ERR_print_errors_fp (stderr);
 
    if ( (p->ssl = SSL_new(p->ssl_ctx)) == NULL)
        ERR_print_errors_fp (stderr);
 
    if (!SSL_set_fd(p->ssl, p->socket))
        ERR_print_errors_fp (stderr);
 
    if (SSL_connect(p->ssl) != 1)
        ERR_print_errors_fp (stderr);
 
    return p;
}
 
void mlt_disconnect(conn *p)
{
    SSL_shutdown(p->ssl);
    close(p->socket);
 
    SSL_free(p->ssl);
    SSL_CTX_free(p->ssl_ctx);
 
    free(p);
}
 
int mlt_ssl_read(conn *p, char *buffer)
{
    int bytes;
 
    memset(buffer, '{FONTE}', BUF_MAX);
    bytes = SSL_read (p->ssl, buffer, BUF_MAX-1);
 
    return bytes;
}
 
int mlt_ssl_write(conn *p, char *cmd)
{
    int ret;
 
    ret = SSL_write(p->ssl, cmd, strlen(cmd));
 
    return ret;
}
 
int main (int argc, char **argv)
{
    conn *server;
    char buffer[BUF_MAX];
    int bytes;
 
    server = mlt_ssl_connect("www.google.com");
 
    mlt_ssl_write(server, "GET /\r\n\r\n");
 
    while (1)
    {
        bytes = mlt_ssl_read(server, buffer);
        if (!bytes) {
            fprintf(stderr, ".-. server disconnected.\n");
            mlt_disconnect(server);
            break;
        }
 
        fprintf(stdout, "%s", buffer);
   }
 
    return 0;
}