path: root/camel/providers/smtp/camel-smtp-transport.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-smtp-transport.c : class for a smtp transport */

/* 
 * Authors: Jeffrey Stedfast <fejj@helixcode.com>
 *
 * Copyright (C) 2000 Helix Code, Inc. (www.helixcode.com)
 *
 * This program is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU General Public License as 
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#undef MIN
#undef MAX
#include "camel-mime-filter-crlf.h"
#include "camel-mime-filter-linewrap.h"
#include "camel-stream-filter.h"
#include "camel-smtp-transport.h"
#include "camel-mime-message.h"
#include "camel-multipart.h"
#include "camel-mime-part.h"
#include "camel-stream-buffer.h"
#include "camel-tcp-stream.h"
#include "camel-tcp-stream-raw.h"
#ifdef HAVE_NSS
#include "camel-tcp-stream-ssl.h"
#include <prnetdb.h>
#endif
#ifdef HAVE_OPENSSL
#include "camel-tcp-stream-openssl.h"
#endif
#include "camel-session.h"
#include "camel-exception.h"
#include "camel-sasl.h"
#include "string-utils.h"

#define d(x) x

/* Specified in RFC 821 */
#define SMTP_PORT 25

/* camel smtp transport class prototypes */
static gboolean smtp_can_send (CamelTransport *transport, CamelMedium *message);
static gboolean smtp_send (CamelTransport *transport, CamelMedium *message, CamelException *ex);
static gboolean smtp_send_to (CamelTransport *transport, CamelMedium *message, GList *recipients, CamelException *ex);

/* support prototypes */
static void smtp_construct (CamelService *service, CamelSession *session,
                CamelProvider *provider, CamelURL *url,
                CamelException *ex);
static gboolean smtp_connect (CamelService *service, CamelException *ex);
static gboolean smtp_disconnect (CamelService *service, gboolean clean, CamelException *ex);
static GHashTable *esmtp_get_authtypes (gchar *buffer);
static GList *query_auth_types (CamelService *service, CamelException *ex);
static char *get_name (CamelService *service, gboolean brief);

static gboolean smtp_helo (CamelSmtpTransport *transport, CamelException *ex);
static gboolean smtp_auth (CamelSmtpTransport *transport, const char *mech, CamelException *ex);
static gboolean smtp_mail (CamelSmtpTransport *transport, const char *sender,
               gboolean has_8bit_parts, CamelException *ex);
static gboolean smtp_rcpt (CamelSmtpTransport *transport, const char *recipient, CamelException *ex);
static gboolean smtp_data (CamelSmtpTransport *transport, CamelMedium *message,
               gboolean has_8bit_parts, CamelException *ex);
static gboolean smtp_rset (CamelSmtpTransport *transport, CamelException *ex);
static gboolean smtp_quit (CamelSmtpTransport *transport, CamelException *ex);

/* private data members */
static CamelTransportClass *parent_class = NULL;

static void
camel_smtp_transport_class_init (CamelSmtpTransportClass *camel_smtp_transport_class)
{
    CamelTransportClass *camel_transport_class =
        CAMEL_TRANSPORT_CLASS (camel_smtp_transport_class);
    CamelServiceClass *camel_service_class =
        CAMEL_SERVICE_CLASS (camel_smtp_transport_class);
    
    parent_class = CAMEL_TRANSPORT_CLASS (camel_type_get_global_classfuncs (camel_transport_get_type ()));
    
    /* virtual method overload */
    camel_service_class->construct = smtp_construct;
    camel_service_class->connect = smtp_connect;
    camel_service_class->disconnect = smtp_disconnect;
    camel_service_class->query_auth_types = query_auth_types;
    camel_service_class->get_name = get_name;

    camel_transport_class->can_send = smtp_can_send;
    camel_transport_class->send = smtp_send;
    camel_transport_class->send_to = smtp_send_to;
}

static void
camel_smtp_transport_init (gpointer object)
{
    CamelTransport *transport = CAMEL_TRANSPORT (object);
    
    transport->supports_8bit = FALSE;
}

CamelType
camel_smtp_transport_get_type (void)
{
    static CamelType camel_smtp_transport_type = CAMEL_INVALID_TYPE;
    
    if (camel_smtp_transport_type == CAMEL_INVALID_TYPE) {
        camel_smtp_transport_type =
            camel_type_register (CAMEL_TRANSPORT_TYPE, "CamelSmtpTransport",
                         sizeof (CamelSmtpTransport),
                         sizeof (CamelSmtpTransportClass),
                         (CamelObjectClassInitFunc) camel_smtp_transport_class_init,
                         NULL,
                         (CamelObjectInitFunc) camel_smtp_transport_init,
                         NULL);
    }
    
    return camel_smtp_transport_type;
}

static void
smtp_construct (CamelService *service, CamelSession *session,
        CamelProvider *provider, CamelURL *url,
        CamelException *ex)
{
    CamelSmtpTransport *smtp_transport = CAMEL_SMTP_TRANSPORT (service);

    CAMEL_SERVICE_CLASS (parent_class)->construct (service, session, provider, url, ex);

    if (camel_url_get_param (url, "use_ssl"))
        smtp_transport->use_ssl = TRUE;
}

static const char *
get_smtp_error_string (int error)
{
    /* SMTP error codes grabbed from rfc821 */
    switch (error) {
    case 0:
        /* looks like a read problem, check errno */
        return g_strerror (errno);
    case 500:
        return _("Syntax error, command unrecognized");
    case 501:
        return _("Syntax error in parameters or arguments");
    case 502:
        return _("Command not implemented");
    case 504:
        return _("Command parameter not implemented");
    case 211:
        return _("System status, or system help reply");
    case 214:
        return _("Help message");
    case 220:
        return _("Service ready");
    case 221:
        return _("Service closing transmission channel");
    case 421:
        return _("Service not available, closing transmission channel");
    case 250:
        return _("Requested mail action okay, completed");
    case 251:
        return _("User not local; will forward to <forward-path>");
    case 450:
        return _("Requested mail action not taken: mailbox unavailable");
    case 550:
        return _("Requested action not taken: mailbox unavailable");
    case 451:
        return _("Requested action aborted: error in processing");
    case 551:
        return _("User not local; please try <forward-path>");
    case 452:
        return _("Requested action not taken: insufficient system storage");
    case 552:
        return _("Requested mail action aborted: exceeded storage allocation");
    case 553:
        return _("Requested action not taken: mailbox name not allowed");
    case 354:
        return _("Start mail input; end with <CRLF>.<CRLF>");
    case 554:
        return _("Transaction failed");
        
    /* AUTH error codes: */
    case 432:
        return _("A password transition is needed");
    case 534:
        return _("Authentication mechanism is too weak");
    case 538:
        return _("Encryption required for requested authentication mechanism");
    case 454:
        return _("Temporary authentication failure");
    case 530:
        return _("Authentication required");
        
    default:
        return _("Unknown");
    }
}

static gboolean
connect_to_server (CamelService *service, CamelException *ex)
{
    CamelSmtpTransport *transport = CAMEL_SMTP_TRANSPORT (service);
    CamelStream *tcp_stream;
    gchar *respbuf = NULL;
    struct hostent *h;
    guint32 addrlen;
    int port, ret;
    
    if (!CAMEL_SERVICE_CLASS (parent_class)->connect (service, ex))
        return FALSE;
    
    h = camel_service_gethost (service, ex);
    if (!h)
        return FALSE;
    
    /* set some smtp transport defaults */
    transport->is_esmtp = FALSE;
    transport->authtypes = NULL;
    CAMEL_TRANSPORT (transport)->supports_8bit = FALSE;
    
    port = service->url->port ? service->url->port : SMTP_PORT;
    
#if defined(HAVE_NSS) || defined(HAVE_OPENSSL)
    if (transport->use_ssl) {
        port = service->url->port ? service->url->port : 465;
#ifdef HAVE_NSS
        /* use the preferred implementation - NSS */
        tcp_stream = camel_tcp_stream_ssl_new (service, service->url->host);
#else
        tcp_stream = camel_tcp_stream_openssl_new (service, service->url->host);
#endif /* HAVE_NSS */
    } else {
        tcp_stream = camel_tcp_stream_raw_new ();
    }
#else
    tcp_stream = camel_tcp_stream_raw_new ();
#endif /* HAVE_NSS || HAVE_OPENSSL */
    
    ret = camel_tcp_stream_connect (CAMEL_TCP_STREAM (tcp_stream), h, port);
    camel_free_host(h);
    if (ret == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_UNAVAILABLE,
                      _("Could not connect to %s (port %d): %s"),
                      service->url->host, port,
                      g_strerror (errno));
        
        return FALSE;
    }
    
    /* get the localaddr - needed later by smtp_helo */
    addrlen = sizeof (transport->localaddr);
#ifdef HAVE_NSS
    if (transport->use_ssl) {
        PRFileDesc *sockfd = camel_tcp_stream_get_socket (CAMEL_TCP_STREAM (tcp_stream));
        PRNetAddr addr;
        char hname[1024];
        
        PR_GetSockName (sockfd, &addr);
        memset (hname, 0, sizeof (hname));
        PR_NetAddrToString (&addr, hname, 1023);
        
        inet_aton (hname, (struct in_addr *)&transport->localaddr.sin_addr);
    } else {
        int sockfd = GPOINTER_TO_INT (camel_tcp_stream_get_socket (CAMEL_TCP_STREAM (tcp_stream)));
        
        getsockname (sockfd, (struct sockaddr *)&transport->localaddr, &addrlen);
    }
#else
    getsockname (CAMEL_TCP_STREAM_RAW (tcp_stream)->sockfd,
             (struct sockaddr *)&transport->localaddr, &addrlen);
#endif /* HAVE_NSS */
    
    transport->ostream = tcp_stream;
    transport->istream = camel_stream_buffer_new (tcp_stream, CAMEL_STREAM_BUFFER_READ);
    
    /* Read the greeting, note whether the server is ESMTP or not. */
    do {
        /* Check for "220" */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        if (!respbuf || strncmp (respbuf, "220", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("Welcome response error: %s: possibly non-fatal"),
                          get_smtp_error_string (error));
            return FALSE;
        }
        if (strstr (respbuf, "ESMTP"))
            transport->is_esmtp = TRUE;
    } while (*(respbuf+3) == '-'); /* if we got "220-" then loop again */
    g_free (respbuf);
    
    /* send HELO (or EHLO, depending on the service type) */
    if (!transport->is_esmtp) {
        /* If we did not auto-detect ESMTP, we should still send EHLO */
        transport->is_esmtp = TRUE;
        if (!smtp_helo (transport, NULL)) {
            /* Okay, apprently this server doesn't support ESMTP */
            transport->is_esmtp = FALSE;
            smtp_helo (transport, ex);
        }
    } else {
        /* send EHLO */
        smtp_helo (transport, ex);
    }
    
    return TRUE;
}

static gboolean
smtp_connect (CamelService *service, CamelException *ex)
{
    CamelSmtpTransport *transport = CAMEL_SMTP_TRANSPORT (service);

    if (!connect_to_server (service, ex))
        return FALSE;

    /* check to see if AUTH is required, if so...then AUTH ourselves */
    if (service->url->authmech) {
        CamelSession *session = camel_service_get_session (service);
        CamelServiceAuthType *authtype;
        gboolean authenticated = FALSE;
        char *errbuf = NULL;
        
        if (!transport->is_esmtp || !g_hash_table_lookup (transport->authtypes, service->url->authmech)) {
            camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_CANT_AUTHENTICATE,
                          _("SMTP server %s does not support requested "
                          "authentication type %s"), service->url->host,
                          service->url->authmech);
            camel_service_disconnect (service, TRUE, NULL);
            return FALSE;
        }
        
        authtype = camel_sasl_authtype (service->url->authmech);
        if (!authtype) {
            camel_exception_setv (ex, CAMEL_EXCEPTION_SERVICE_CANT_AUTHENTICATE,
                          _("No support for authentication type %s"),
                          service->url->authmech);
            camel_service_disconnect (service, TRUE, NULL);
            return FALSE;
        }
        
        if (!authtype->need_password) {
            /* authentication mechanism doesn't need a password,
               so if it fails there's nothing we can do */
            authenticated = smtp_auth (transport, authtype->authproto, ex);
            if (!authenticated) {
                camel_service_disconnect (service, TRUE, NULL);
                return FALSE;
            }
        }
        
        /* keep trying to login until either we succeed or the user cancels */
        while (!authenticated) {
            if (errbuf) {
                /* We need to un-cache the password before prompting again */
                camel_session_forget_password (
                    session, service, "password", ex);
                g_free (service->url->passwd);
                service->url->passwd = NULL;
            }
            
            if (!service->url->passwd) {
                char *prompt;
                
                prompt = g_strdup_printf (_("%sPlease enter the SMTP password for %s@%s"),
                              errbuf ? errbuf : "", service->url->user,
                              service->url->host);
                
                service->url->passwd =
                    camel_session_get_password (
                        session, prompt, TRUE,
                        service, "password", ex);
                
                g_free (prompt);
                g_free (errbuf);
                errbuf = NULL;
                
                if (!service->url->passwd) {
                    camel_exception_set (ex, CAMEL_EXCEPTION_USER_CANCEL,
                                 _("You didn't enter a password."));
                    camel_service_disconnect (service, TRUE, NULL);
                    return FALSE;
                }
            }
            
            authenticated = smtp_auth (transport, authtype->authproto, ex);
            if (!authenticated) {
                errbuf = g_strdup_printf (_("Unable to authenticate "
                                "to SMTP server.\n%s\n\n"),
                              camel_exception_get_description (ex));
                camel_exception_clear (ex);
            }
        }
        
        /* The spec says we have to re-EHLO, but some servers
         * we won't bother to name don't want you to... so ignore
         * errors.
         */
        smtp_helo (transport, NULL);
    }
    
    return TRUE;
}

static gboolean
authtypes_free (gpointer key, gpointer value, gpointer data)
{
    g_free (key);
    g_free (value);
    
    return TRUE;
}

static gboolean
smtp_disconnect (CamelService *service, gboolean clean, CamelException *ex)
{
    CamelSmtpTransport *transport = CAMEL_SMTP_TRANSPORT (service);
    
    /*if (!service->connected)
     *  return TRUE;
     */
    
    if (clean) {
        /* send the QUIT command to the SMTP server */
        smtp_quit (transport, ex);
    }
    
    if (!CAMEL_SERVICE_CLASS (parent_class)->disconnect (service, clean, ex))
        return FALSE;
    
    if (transport->authtypes) {
        g_hash_table_foreach_remove (transport->authtypes, authtypes_free, NULL);
        g_hash_table_destroy (transport->authtypes);
        transport->authtypes = NULL;
    }
    
    camel_object_unref (CAMEL_OBJECT (transport->ostream));
    camel_object_unref (CAMEL_OBJECT (transport->istream));
    
    transport->ostream = NULL;
    transport->istream = NULL;
    
    return TRUE;
}

static GHashTable *
esmtp_get_authtypes (char *buffer)
{
    GHashTable *table = NULL;
    gchar *start, *end;
    
    /* advance to the first token */
    for (start = buffer; isspace (*start) || *start == '='; start++);
    
    if (!*start) return NULL;
    
    table = g_hash_table_new (g_str_hash, g_str_equal);
    
    for ( ; *start; ) {
        char *type;
        
        /* advance to the end of the token */
        for (end = start; *end && !isspace (*end); end++);
        
        type = g_strndup (start, end - start);
        g_hash_table_insert (table, g_strdup (type), type);
        
        /* advance to the next token */
        for (start = end; isspace (*start); start++);
    }
    
    return table;
}

static GList *
query_auth_types (CamelService *service, CamelException *ex)
{
    CamelSmtpTransport *transport = CAMEL_SMTP_TRANSPORT (service);
    CamelServiceAuthType *authtype;
    GList *types, *t, *next;
    
    if (!connect_to_server (service, ex))
        return NULL;
    
    types = g_list_copy (service->provider->authtypes);
    for (t = types; t; t = next) {
        authtype = t->data;
        next = t->next;
        
        if (!g_hash_table_lookup (transport->authtypes, authtype->authproto)) {
            types = g_list_remove_link (types, t);
            g_list_free_1 (t);
        }
    }
    
    smtp_disconnect (service, TRUE, NULL);
    return types;
}

static char *
get_name (CamelService *service, gboolean brief)
{
    if (brief)
        return g_strdup_printf (_("SMTP server %s"), service->url->host);
    else {
        return g_strdup_printf (_("SMTP mail delivery via %s"),
                    service->url->host);
    }
}

static gboolean
smtp_can_send (CamelTransport *transport, CamelMedium *message)
{
    return CAMEL_IS_MIME_MESSAGE (message);
}

static gboolean
smtp_send_to (CamelTransport *transport, CamelMedium *message,
          GList *recipients, CamelException *ex)
{
    CamelSmtpTransport *smtp_transport = CAMEL_SMTP_TRANSPORT (transport);
    const CamelInternetAddress *cia;
    char *recipient;
    const char *addr;
    gboolean has_8bit_parts;
    GList *r;
    
    cia = camel_mime_message_get_from(CAMEL_MIME_MESSAGE (message));
    if (!cia) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Cannot send message: "
                    "sender address not defined."));
        return FALSE;
    }
    
    if (!camel_internet_address_get (cia, 0, NULL, &addr)) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Cannot send message: "
                    "sender address not valid."));
        return FALSE;
    }
    
    /* find out if the message has 8bit mime parts */
    has_8bit_parts = camel_mime_message_has_8bit_parts (CAMEL_MIME_MESSAGE (message));
    
    /* rfc1652 (8BITMIME) requires that you notify the ESMTP daemon that
       you'll be sending an 8bit mime message at "MAIL FROM:" time. */
    smtp_mail (smtp_transport, addr, has_8bit_parts, ex);
    
    if (!recipients) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Cannot send message: "
                    "no recipients defined."));
        return FALSE;
    }
    
    for (r = recipients; r; r = r->next) {
        recipient = (char *) r->data;
        if (!smtp_rcpt (smtp_transport, recipient, ex)) {
            g_free (recipient);
            return FALSE;
        }
        g_free (recipient);
    }
    
    /* passing in has_8bit_parts saves time as we don't have to
           recurse through the message all over again if the user is
           not sending 8bit mime parts */
    if (!smtp_data (smtp_transport, message, has_8bit_parts, ex))
        return FALSE;
    
    /* reset the service for our next transfer session */
    smtp_rset (smtp_transport, ex);
    
    return TRUE;
}

static gboolean
smtp_send (CamelTransport *transport, CamelMedium *message, CamelException *ex)
{
    const CamelInternetAddress *to, *cc, *bcc;
    GList *recipients = NULL;
    guint index, len;
    
    to = camel_mime_message_get_recipients (CAMEL_MIME_MESSAGE (message), CAMEL_RECIPIENT_TYPE_TO);
    cc = camel_mime_message_get_recipients (CAMEL_MIME_MESSAGE (message), CAMEL_RECIPIENT_TYPE_CC);
    bcc = camel_mime_message_get_recipients (CAMEL_MIME_MESSAGE (message), CAMEL_RECIPIENT_TYPE_BCC);
    
    /* get all of the To addresses into our recipient list */
    len = CAMEL_ADDRESS (to)->addresses->len;
    for (index = 0; index < len; index++) {
        const char *addr;
        
        if (camel_internet_address_get (to, index, NULL, &addr))
            recipients = g_list_append (recipients, g_strdup (addr));
    }
    
    /* get all of the Cc addresses into our recipient list */
    len = CAMEL_ADDRESS (cc)->addresses->len;
    for (index = 0; index < len; index++) {
        const char *addr;
        
        if (camel_internet_address_get (cc, index, NULL, &addr))
            recipients = g_list_append (recipients, g_strdup (addr));
    }
    
    /* get all of the Bcc addresses into our recipient list */
    len = CAMEL_ADDRESS (bcc)->addresses->len;
    for (index = 0; index < len; index++) {
        const char *addr;
        
        if (camel_internet_address_get (bcc, index, NULL, &addr))
            recipients = g_list_append (recipients, g_strdup (addr));
    }
    
    return smtp_send_to (transport, message, recipients, ex);
}

static gboolean
smtp_helo (CamelSmtpTransport *transport, CamelException *ex)
{
    /* say hello to the server */
    gchar *cmdbuf, *respbuf = NULL;
    struct hostent *host;
    
    /* get the local host name */
    host = gethostbyaddr ((gchar *)&transport->localaddr.sin_addr, sizeof (transport->localaddr.sin_addr), AF_INET);
    
    /* hiya server! how are you today? */
    if (transport->is_esmtp) {
        if (host && host->h_name)
            cmdbuf = g_strdup_printf ("EHLO %s\r\n", host->h_name);
        else
            cmdbuf = g_strdup_printf ("EHLO [%s]\r\n", inet_ntoa (transport->localaddr.sin_addr));
    } else {
        if (host && host->h_name)
            cmdbuf = g_strdup_printf ("HELO %s\r\n", host->h_name);
        else
            cmdbuf = g_strdup_printf ("HELO [%s]\r\n", inet_ntoa (transport->localaddr.sin_addr));
    }
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("HELO request timed out: %s: non-fatal"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    do {
        /* Check for "250" */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "250", 3)) {
            int error;

            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("HELO response error: %s: non-fatal"),
                          get_smtp_error_string (error));
            return FALSE;
        }
        
        if (strstrcase (respbuf, "8BITMIME")) {
            d(fprintf (stderr, "This server supports 8bit MIME\n"));
            CAMEL_TRANSPORT (transport)->supports_8bit = TRUE;
        }
        
        /* Only parse authtypes if we don't already have them */
        if (transport->is_esmtp && strstr (respbuf, "AUTH") && !transport->authtypes) {
            /* parse for supported AUTH types */
            char *auths = strstr (respbuf, "AUTH") + 4;
            
            transport->authtypes = esmtp_get_authtypes (auths);
        }
    } while (*(respbuf+3) == '-'); /* if we got "250-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}

static gboolean
smtp_auth (CamelSmtpTransport *transport, const char *mech, CamelException *ex)
{
    gchar *cmdbuf, *respbuf = NULL, *challenge;
    CamelSasl *sasl;
    
    sasl = camel_sasl_new ("smtp", mech, CAMEL_SERVICE (transport));
    if (!sasl) {
        g_free (respbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("Error creating SASL authentication object."));
        return FALSE;
    }
    
    challenge = camel_sasl_challenge_base64 (sasl, NULL, ex);
    if (challenge) {
        cmdbuf = g_strdup_printf ("AUTH %s %s\r\n", mech, challenge);
        g_free (challenge);
    } else
        cmdbuf = g_strdup_printf ("AUTH %s\r\n", mech);
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("AUTH request timed out: %s"),
                      g_strerror (errno));
        goto lose;
    }
    g_free (cmdbuf);
    
    respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
    d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
    
    while (!camel_sasl_authenticated (sasl)) {
        if (!respbuf) {
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("AUTH request timed out: %s"),
                          g_strerror (errno));
            goto lose;
        }
        
        /* the server challenge/response should follow a 334 code */
        if (strcmp (respbuf, "334")) {
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("AUTH request failed."));
            goto lose;
        }
        
        /* eat whtspc */
        for (challenge = respbuf + 4; isspace (*challenge); challenge++);
        
        challenge = camel_sasl_challenge_base64 (sasl, challenge, ex);
        g_free (respbuf);
        if (camel_exception_is_set (ex))
            goto break_and_lose;
        
        /* send our challenge */
        cmdbuf = g_strdup_printf ("%s\r\n", challenge);
        g_free (challenge);
        d(fprintf (stderr, "sending : %s", cmdbuf));
        if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
            g_free (cmdbuf);
            goto lose;
        }
        g_free (cmdbuf);
        
        /* get the server's response */
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
    }
    
    /* check that the server says we are authenticated */
    if (!respbuf || strncmp (respbuf, "235", 3)) {
        g_free (respbuf);
        goto lose;
    }
    
    return TRUE;
    
 break_and_lose:
    /* Get the server out of "waiting for continuation data" mode. */
    d(fprintf (stderr, "sending : *\n"));
    camel_stream_write (transport->ostream, "*\r\n", 3);
    respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
    d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
    
 lose:
    if (!camel_exception_is_set (ex)) {
        camel_exception_set (ex, CAMEL_EXCEPTION_SERVICE_CANT_AUTHENTICATE,
                     _("Bad authentication response from server.\n"));
    }
    
    if (sasl)
        camel_object_unref (CAMEL_OBJECT (sasl));
    
    return FALSE;
}

static gboolean
smtp_mail (CamelSmtpTransport *transport, const char *sender, gboolean has_8bit_parts, CamelException *ex)
{
    /* we gotta tell the smtp server who we are. (our email addy) */
    gchar *cmdbuf, *respbuf = NULL;
    
    /* enclose address in <>'s since some SMTP daemons *require* that */
    if (CAMEL_TRANSPORT (transport)->supports_8bit && has_8bit_parts)
        cmdbuf = g_strdup_printf ("MAIL FROM: <%s> BODY=8BITMIME\r\n", sender);
    else
        cmdbuf = g_strdup_printf ("MAIL FROM: <%s>\r\n", sender);
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("MAIL FROM request timed out: %s: mail not sent"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    do {
        /* Check for "250 Sender OK..." */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "250", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("MAIL FROM response error: %s: mail not sent"),
                          get_smtp_error_string (error));
            return FALSE;
        }
    } while (*(respbuf+3) == '-'); /* if we got "250-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}

static gboolean
smtp_rcpt (CamelSmtpTransport *transport, const char *recipient, CamelException *ex)
{
    /* we gotta tell the smtp server who we are going to be sending
     * our email to */
    gchar *cmdbuf, *respbuf = NULL;
    
    /* enclose address in <>'s since some SMTP daemons *require* that */
    cmdbuf = g_strdup_printf ("RCPT TO: <%s>\r\n", recipient);
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("RCPT TO request timed out: %s: mail not sent"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    do {
        /* Check for "250 Sender OK..." */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "250", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("RCPT TO response error: %s: mail not sent"),
                          get_smtp_error_string (error));
            return FALSE;
        }
    } while (*(respbuf+3) == '-'); /* if we got "250-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}

static gboolean
smtp_data (CamelSmtpTransport *transport, CamelMedium *message, gboolean has_8bit_parts, CamelException *ex)
{
    /* now we can actually send what's important :p */
    gchar *cmdbuf, *respbuf = NULL;
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *crlffilter;
    
    /* if the message contains 8bit mime parts and the server
           doesn't support it, encode 8bit parts to the best
           encoding.  This will also enforce an encoding to keep the lines in limit */
    if (has_8bit_parts && !CAMEL_TRANSPORT (transport)->supports_8bit)
        camel_mime_message_encode_8bit_parts (CAMEL_MIME_MESSAGE (message));
    
    cmdbuf = g_strdup ("DATA\r\n");
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("DATA request timed out: %s: mail not sent"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
    
    d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
    
    if (!respbuf || strncmp (respbuf, "354", 3)) {
        /* we should have gotten instructions on how to use the DATA command:
         * 354 Enter mail, end with "." on a line by itself
         */
        int error;
            
        error = respbuf ? atoi (respbuf) : 0;
        g_free (respbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("DATA response error: %s: mail not sent"),
                      get_smtp_error_string (error));
        return FALSE;
    }

    g_free (respbuf);
    respbuf = NULL;
    
    /* setup stream filtering */
    crlffilter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_ENCODE, CAMEL_MIME_FILTER_CRLF_MODE_CRLF_DOTS);
    filtered_stream = camel_stream_filter_new_with_stream (transport->ostream);
    camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (crlffilter));
    
    if (camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (message), CAMEL_STREAM (filtered_stream)) == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("DATA send timed out: message termination: "
                    "%s: mail not sent"),
                      g_strerror (errno));
        
        camel_object_unref (CAMEL_OBJECT (filtered_stream));
        
        return FALSE;
    }
    
    camel_stream_flush (CAMEL_STREAM (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (filtered_stream));
    
    /* terminate the message body */
    
    d(fprintf (stderr, "sending : \\r\\n.\\r\\n\n"));
    
    if (camel_stream_write (transport->ostream, "\r\n.\r\n", 5) == -1) {
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("DATA send timed out: message termination: "
                    "%s: mail not sent"),
                      g_strerror (errno));
        return FALSE;
    }
    
    do {
        /* Check for "250 Sender OK..." */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "250", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("DATA response error: message termination: "
                        "%s: mail not sent"),
                          get_smtp_error_string (error));
            return FALSE;
        }
    } while (*(respbuf+3) == '-'); /* if we got "250-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}

static gboolean
smtp_rset (CamelSmtpTransport *transport, CamelException *ex)
{
    /* we are going to reset the smtp server (just to be nice) */
    gchar *cmdbuf, *respbuf = NULL;
    
    cmdbuf = g_strdup ("RSET\r\n");
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("RSET request timed out: %s"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    do {
        /* Check for "250" */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "250", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("RSET response error: %s"),
                          get_smtp_error_string (error));
            return FALSE;
        }
    } while (*(respbuf+3) == '-'); /* if we got "250-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}

static gboolean
smtp_quit (CamelSmtpTransport *transport, CamelException *ex)
{
    /* we are going to reset the smtp server (just to be nice) */
    gchar *cmdbuf, *respbuf = NULL;
    
    cmdbuf = g_strdup ("QUIT\r\n");
    
    d(fprintf (stderr, "sending : %s", cmdbuf));
    
    if (camel_stream_write (transport->ostream, cmdbuf, strlen (cmdbuf)) == -1) {
        g_free (cmdbuf);
        camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                      _("QUIT request timed out: %s: non-fatal"),
                      g_strerror (errno));
        return FALSE;
    }
    g_free (cmdbuf);
    
    do {
        /* Check for "221" */
        g_free (respbuf);
        respbuf = camel_stream_buffer_read_line (CAMEL_STREAM_BUFFER (transport->istream));
        
        d(fprintf (stderr, "received: %s\n", respbuf ? respbuf : "(null)"));
        
        if (!respbuf || strncmp (respbuf, "221", 3)) {
            int error;
            
            error = respbuf ? atoi (respbuf) : 0;
            g_free (respbuf);
            camel_exception_setv (ex, CAMEL_EXCEPTION_SYSTEM,
                          _("QUIT response error: %s: non-fatal"),
                          get_smtp_error_string (error));
            return FALSE;
        }
    } while (*(respbuf+3) == '-'); /* if we got "221-" then loop again */
    g_free (respbuf);
    
    return TRUE;
}