src/common/smtp.c

   1 /*
   2  * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
   3  * Copyright (C) 1999-2012 Hiroyuki Yamamoto and the Claws Mail team
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  17  *
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include "config.h"
  22 #include "claws-features.h"
  23 #endif
  24
  25 #include <glib.h>
  26 #ifdef ENABLE_NLS
  27 #include <glib/gi18n.h>
  28 #else
  29 #define _(a) (a)
  30 #define N_(a) (a)
  31 #endif
  32 #include <stdio.h>
  33 #include <string.h>
  34
  35 #include "smtp.h"
  36 #include "md5.h"
  37 #include "base64.h"
  38 #include "utils.h"
  39 #include "log.h"
  40
  41 static void smtp_session_destroy(Session *session);
  42
  43 static gint smtp_auth(SMTPSession *session);
  44 #ifdef USE_GNUTLS
  45 static gint smtp_starttls(SMTPSession *session);
  46 #endif
  47 static gint smtp_auth_cram_md5(SMTPSession *session);
  48 static gint smtp_auth_login(SMTPSession *session);
  49 static gint smtp_auth_plain(SMTPSession *session);
  50
  51 static gint smtp_ehlo(SMTPSession *session);
  52 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg);
  53
  54 static gint smtp_helo(SMTPSession *session);
  55 static gint smtp_rcpt(SMTPSession *session);
  56 static gint smtp_data(SMTPSession *session);
  57 static gint smtp_send_data(SMTPSession *session);
  58 static gint smtp_make_ready(SMTPSession *session);
  59 static gint smtp_eom(SMTPSession *session);
  60
  61 static gint smtp_session_recv_msg(Session *session, const gchar *msg);
  62 static gint smtp_session_send_data_finished(Session *session, guint len);
  63
  64
  65 Session *smtp_session_new(void *prefs_account)
  66 {
  67         SMTPSession *session;
  68
  69         session = g_new0(SMTPSession, 1);
  70
  71         session_init(SESSION(session), prefs_account, TRUE);
  72
  73         SESSION(session)->type             = SESSION_SMTP;
  74
  75         SESSION(session)->recv_msg         = smtp_session_recv_msg;
  76
  77         SESSION(session)->recv_data_finished = NULL;
  78         SESSION(session)->send_data_finished = smtp_session_send_data_finished;
  79
  80         SESSION(session)->destroy          = smtp_session_destroy;
  81
  82         session->state                     = SMTP_READY;
  83
  84 #ifdef USE_GNUTLS
  85         session->tls_init_done             = FALSE;
  86 #endif
  87
  88         session->hostname                  = NULL;
  89         session->user                      = NULL;
  90         session->pass                      = NULL;
  91
  92         session->from                      = NULL;
  93         session->to_list                   = NULL;
  94         session->cur_to                    = NULL;
  95
  96         session->send_data                 = NULL;
  97         session->send_data_len             = 0;
  98
  99         session->max_message_size          = -1;
 100
 101         session->avail_auth_type           = 0;
 102         session->forced_auth_type          = 0;
 103         session->auth_type                 = 0;
 104         session->esmtp_flags               = 0;
 105
 106         session->error_val                 = SM_OK;
 107         session->error_msg                 = NULL;
 108
 109         return SESSION(session);
 110 }
 111
 112 static void smtp_session_destroy(Session *session)
 113 {
 114         SMTPSession *smtp_session = SMTP_SESSION(session);
 115
 116         g_free(smtp_session->hostname);
 117         g_free(smtp_session->user);
 118         g_free(smtp_session->pass);
 119         g_free(smtp_session->from);
 120
 121         g_free(smtp_session->send_data);
 122
 123         g_free(smtp_session->error_msg);
 124 }
 125
 126 gint smtp_from(SMTPSession *session)
 127 {
 128         gchar buf[MESSAGEBUFSIZE];
 129         gchar *mail_size = NULL;
 130
 131         cm_return_val_if_fail(session->from != NULL, SM_ERROR);
 132
 133         session->state = SMTP_FROM;
 134
 135         if (session->is_esmtp && (session->esmtp_flags & ESMTP_SIZE)!=0)
 136                 mail_size = g_strdup_printf(" SIZE=%d", session->send_data_len);
 137         else
 138                 mail_size = g_strdup("");
 139
 140
 141         if (strchr(session->from, '<'))
 142                 g_snprintf(buf, sizeof(buf), "MAIL FROM:%s%s", session->from,
 143                            mail_size);
 144         else
 145                 g_snprintf(buf, sizeof(buf), "MAIL FROM:<%s>%s", session->from,
 146                            mail_size);
 147
 148         g_free(mail_size);
 149
 150         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 151                 return SM_ERROR;
 152         log_print(LOG_PROTOCOL, "%sSMTP> %s\n", (session->is_esmtp?"E":""), buf);
 153
 154         return SM_OK;
 155 }
 156
 157 static gint smtp_auth(SMTPSession *session)
 158 {
 159
 160         cm_return_val_if_fail(session->user != NULL, SM_ERROR);
 161
 162         session->state = SMTP_AUTH;
 163
 164         if ((session->forced_auth_type == SMTPAUTH_CRAM_MD5
 165              || session->forced_auth_type == 0)
 166             &&
 167              (session->avail_auth_type & SMTPAUTH_CRAM_MD5) != 0)
 168                 smtp_auth_cram_md5(session);
 169         else if ((session->forced_auth_type == SMTPAUTH_LOGIN
 170                   || session->forced_auth_type == 0)
 171                  &&
 172                   (session->avail_auth_type & SMTPAUTH_LOGIN) != 0)
 173                 smtp_auth_login(session);
 174         else if ((session->forced_auth_type == SMTPAUTH_PLAIN
 175                   || session->forced_auth_type == 0)
 176                  &&
 177                   (session->avail_auth_type & SMTPAUTH_PLAIN) != 0)
 178                 smtp_auth_plain(session);
 179         else if (session->forced_auth_type == 0) {
 180                 log_warning(LOG_PROTOCOL, _("No SMTP AUTH method available\n"));
 181                 return SM_AUTHFAIL;
 182         } else {
 183                 log_warning(LOG_PROTOCOL, _("Selected SMTP AUTH method not available\n"));
 184                 return SM_AUTHFAIL;
 185         }
 186
 187         return SM_OK;
 188 }
 189
 190 static gint smtp_auth_recv(SMTPSession *session, const gchar *msg)
 191 {
 192         gchar buf[MESSAGEBUFSIZE];
 193
 194         switch (session->auth_type) {
 195         case SMTPAUTH_LOGIN:
 196                 session->state = SMTP_AUTH_LOGIN_USER;
 197
 198                 if (!strncmp(msg, "334 ", 4)) {
 199                         base64_encode(buf, session->user, strlen(session->user));
 200
 201                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 202                                          buf) < 0)
 203                                 return SM_ERROR;
 204                         log_print(LOG_PROTOCOL, "ESMTP> [USERID]\n");
 205                 } else {
 206                         /* Server rejects AUTH */
 207                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 208                                          "*") < 0)
 209                                 return SM_ERROR;
 210                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 211                 }
 212                 break;
 213         case SMTPAUTH_CRAM_MD5:
 214                 session->state = SMTP_AUTH_CRAM_MD5;
 215
 216                 if (!strncmp(msg, "334 ", 4)) {
 217                         gchar *response;
 218                         gchar *response64;
 219                         gchar *challenge;
 220                         gint challengelen;
 221                         guchar hexdigest[33];
 222
 223                         challenge = g_malloc(strlen(msg + 4) + 1);
 224                         challengelen = base64_decode(challenge, msg + 4, -1);
 225                         challenge[challengelen] = '\0';
 226                         log_print(LOG_PROTOCOL, "ESMTP< [Decoded: %s]\n", challenge);
 227
 228                         g_snprintf(buf, sizeof(buf), "%s", session->pass);
 229                         md5_hex_hmac(hexdigest, challenge, challengelen,
 230                                      buf, strlen(session->pass));
 231                         g_free(challenge);
 232
 233                         response = g_strdup_printf
 234                                 ("%s %s", session->user, hexdigest);
 235                         log_print(LOG_PROTOCOL, "ESMTP> [Encoded: %s]\n", response);
 236
 237                         response64 = g_malloc((strlen(response) + 3) * 2 + 1);
 238                         base64_encode(response64, response, strlen(response));
 239                         g_free(response);
 240
 241                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 242                                          response64) < 0)
 243                                 return SM_ERROR;
 244                         log_print(LOG_PROTOCOL, "ESMTP> %s\n", response64);
 245                         g_free(response64);
 246                 } else {
 247                         /* Server rejects AUTH */
 248                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 249                                          "*") < 0)
 250                                 return SM_ERROR;
 251                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 252                 }
 253                 break;
 254         case SMTPAUTH_DIGEST_MD5:
 255         default:
 256                 /* stop smtp_auth when no correct authtype */
 257                 if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "*") < 0)
 258                         return SM_ERROR;
 259                 log_print(LOG_PROTOCOL, "ESMTP> *\n");
 260                 break;
 261         }
 262
 263         return SM_OK;
 264 }
 265
 266 static gint smtp_auth_login_user_recv(SMTPSession *session, const gchar *msg)
 267 {
 268         gchar buf[MESSAGEBUFSIZE];
 269
 270         session->state = SMTP_AUTH_LOGIN_PASS;
 271
 272         if (!strncmp(msg, "334 ", 4))
 273                 base64_encode(buf, session->pass, strlen(session->pass));
 274         else
 275                 /* Server rejects AUTH */
 276                 g_snprintf(buf, sizeof(buf), "*");
 277
 278         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 279                 return SM_ERROR;
 280
 281         log_print(LOG_PROTOCOL, "ESMTP> [PASSWORD]\n");
 282
 283         return SM_OK;
 284 }
 285
 286 static gint smtp_ehlo(SMTPSession *session)
 287 {
 288         gchar buf[MESSAGEBUFSIZE];
 289
 290         session->state = SMTP_EHLO;
 291
 292         session->avail_auth_type = 0;
 293
 294         g_snprintf(buf, sizeof(buf), "EHLO %s",
 295                    session->hostname ? session->hostname : get_domain_name());
 296         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 297                 return SM_ERROR;
 298         log_print(LOG_PROTOCOL, "ESMTP> %s\n", buf);
 299
 300         return SM_OK;
 301 }
 302
 303 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg)
 304 {
 305         if (strncmp(msg, "250", 3) == 0) {
 306                 const gchar *p = msg;
 307                 p += 3;
 308                 if (*p == '-' || *p == ' ') p++;
 309                 if (g_ascii_strncasecmp(p, "AUTH", 4) == 0) {
 310                         p += 5;
 311                         if (strcasestr(p, "PLAIN"))
 312                                 session->avail_auth_type |= SMTPAUTH_PLAIN;
 313                         if (strcasestr(p, "LOGIN"))
 314                                 session->avail_auth_type |= SMTPAUTH_LOGIN;
 315                         if (strcasestr(p, "CRAM-MD5"))
 316                                 session->avail_auth_type |= SMTPAUTH_CRAM_MD5;
 317                         if (strcasestr(p, "DIGEST-MD5"))
 318                                 session->avail_auth_type |= SMTPAUTH_DIGEST_MD5;
 319                 }
 320                 if (g_ascii_strncasecmp(p, "SIZE", 4) == 0) {
 321                         p += 5;
 322                         session->max_message_size = atoi(p);
 323                         session->esmtp_flags |= ESMTP_SIZE;
 324                 }
 325                 if (g_ascii_strncasecmp(p, "STARTTLS", 8) == 0) {
 326                         p += 9;
 327                         session->avail_auth_type |= SMTPAUTH_TLS_AVAILABLE;
 328                 }
 329                 return SM_OK;
 330         } else if ((msg[0] == '1' || msg[0] == '2' || msg[0] == '3') &&
 331             (msg[3] == ' ' || msg[3] == '\0'))
 332                 return SM_OK;
 333         else if (msg[0] == '5' && msg[1] == '0' &&
 334                  (msg[2] == '4' || msg[2] == '3' || msg[2] == '1'))
 335                 return SM_ERROR;
 336
 337         return SM_ERROR;
 338 }
 339
 340 #ifdef USE_GNUTLS
 341 static gint smtp_starttls(SMTPSession *session)
 342 {
 343         session->state = SMTP_STARTTLS;
 344
 345         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "STARTTLS") < 0)
 346                 return SM_ERROR;
 347         log_print(LOG_PROTOCOL, "ESMTP> STARTTLS\n");
 348
 349         return SM_OK;
 350 }
 351 #endif
 352
 353 static gint smtp_auth_cram_md5(SMTPSession *session)
 354 {
 355         session->state = SMTP_AUTH;
 356         session->auth_type = SMTPAUTH_CRAM_MD5;
 357
 358         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "AUTH CRAM-MD5") < 0)
 359                 return SM_ERROR;
 360         log_print(LOG_PROTOCOL, "ESMTP> AUTH CRAM-MD5\n");
 361
 362         return SM_OK;
 363 }
 364
 365 static gint smtp_auth_plain(SMTPSession *session)
 366 {
 367         gchar buf[MESSAGEBUFSIZE];
 368
 369         /*
 370          * +1      +1      +1
 371          * \0<user>\0<pass>\0
 372          */
 373         int b64len = (1 + strlen(session->user) + 1 + strlen(session->pass) + 1);
 374         gchar *b64buf = g_malloc(b64len);
 375
 376         /* use the char *ptr to walk the base64 string with embedded \0 */
 377         char  *a = b64buf;
 378         int  b64cnt = 0;
 379
 380         session->state = SMTP_AUTH_PLAIN;
 381         session->auth_type = SMTPAUTH_PLAIN;
 382
 383         memset(buf, 0, sizeof buf);
 384
 385         /*
 386          * have to construct the string bit by bit. sprintf can't do it in one.
 387          * first field is null, so string is \0<user>\0<password>
 388          */
 389         *a = 0;
 390         a++;
 391
 392         g_snprintf (a, b64len - 1, "%s", session->user);
 393
 394         b64cnt = strlen(session->user)+1;
 395         a += b64cnt;
 396
 397         g_snprintf (a, b64len - b64cnt - 1, "%s", session->pass);
 398         b64cnt += strlen(session->pass) + 1;
 399
 400         /*
 401          * reuse the char *ptr to offset into the textbuf to meld
 402          * the plaintext ESMTP message and the base64 string value
 403          */
 404         strcpy(buf, "AUTH PLAIN ");
 405         a = buf + strlen(buf);
 406         base64_encode(a, b64buf, b64cnt);
 407
 408         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 409                 return SM_ERROR;
 410
 411         log_print(LOG_PROTOCOL, "ESMTP> [AUTH PLAIN]\n");
 412
 413         g_free(b64buf);
 414
 415         return SM_OK;
 416 }
 417
 418 static gint smtp_auth_login(SMTPSession *session)
 419 {
 420         session->state = SMTP_AUTH;
 421         session->auth_type = SMTPAUTH_LOGIN;
 422
 423         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "AUTH LOGIN") < 0)
 424                 return SM_ERROR;
 425         log_print(LOG_PROTOCOL, "ESMTP> AUTH LOGIN\n");
 426
 427         return SM_OK;
 428 }
 429
 430 static gint smtp_helo(SMTPSession *session)
 431 {
 432         gchar buf[MESSAGEBUFSIZE];
 433
 434         session->state = SMTP_HELO;
 435
 436         g_snprintf(buf, sizeof(buf), "HELO %s",
 437                    session->hostname ? session->hostname : get_domain_name());
 438         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 439                 return SM_ERROR;
 440         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 441
 442         return SM_OK;
 443 }
 444
 445 static gint smtp_rcpt(SMTPSession *session)
 446 {
 447         gchar buf[MESSAGEBUFSIZE];
 448         gchar *to;
 449
 450         cm_return_val_if_fail(session->cur_to != NULL, SM_ERROR);
 451
 452         session->state = SMTP_RCPT;
 453
 454         to = (gchar *)session->cur_to->data;
 455
 456         if (strchr(to, '<'))
 457                 g_snprintf(buf, sizeof(buf), "RCPT TO:%s", to);
 458         else
 459                 g_snprintf(buf, sizeof(buf), "RCPT TO:<%s>", to);
 460         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 461                 return SM_ERROR;
 462         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 463
 464         session->cur_to = session->cur_to->next;
 465
 466         return SM_OK;
 467 }
 468
 469 static gint smtp_data(SMTPSession *session)
 470 {
 471         session->state = SMTP_DATA;
 472
 473         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "DATA") < 0)
 474                 return SM_ERROR;
 475         log_print(LOG_PROTOCOL, "SMTP> DATA\n");
 476
 477         return SM_OK;
 478 }
 479
 480 static gint smtp_send_data(SMTPSession *session)
 481 {
 482         session->state = SMTP_SEND_DATA;
 483
 484         session_send_data(SESSION(session), session->send_data,
 485                           session->send_data_len);
 486
 487         return SM_OK;
 488 }
 489
 490 static gint smtp_make_ready(SMTPSession *session)
 491 {
 492         session->state = SMTP_MAIL_SENT_OK;
 493
 494         return SM_OK;
 495 }
 496
 497 gint smtp_quit(SMTPSession *session)
 498 {
 499         session->state = SMTP_QUIT;
 500
 501         session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "QUIT");
 502         log_print(LOG_PROTOCOL, "SMTP> QUIT\n");
 503
 504         return SM_OK;
 505 }
 506
 507 static gint smtp_eom(SMTPSession *session)
 508 {
 509         session->state = SMTP_EOM;
 510
 511         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, ".") < 0)
 512                 return SM_ERROR;
 513         log_print(LOG_PROTOCOL, "SMTP> . (EOM)\n");
 514
 515         return SM_OK;
 516 }
 517
 518 static gint smtp_session_recv_msg(Session *session, const gchar *msg)
 519 {
 520         SMTPSession *smtp_session = SMTP_SESSION(session);
 521         gboolean cont = FALSE;
 522         gint ret = 0;
 523
 524         if (strlen(msg) < 4) {
 525                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 526                 return -1;
 527         }
 528
 529         switch (smtp_session->state) {
 530         case SMTP_EHLO:
 531         case SMTP_STARTTLS:
 532         case SMTP_AUTH:
 533         case SMTP_AUTH_PLAIN:
 534         case SMTP_AUTH_LOGIN_USER:
 535         case SMTP_AUTH_LOGIN_PASS:
 536         case SMTP_AUTH_CRAM_MD5:
 537                 log_print(LOG_PROTOCOL, "ESMTP< %s\n", msg);
 538                 break;
 539         default:
 540                 log_print(LOG_PROTOCOL, "SMTP< %s\n", msg);
 541                 break;
 542         }
 543
 544         /* ignore all multiline responses except for EHLO */
 545         if (msg[3] == '-' && smtp_session->state != SMTP_EHLO)
 546                 return session_recv_msg(session);
 547
 548         if (msg[0] == '5' && msg[1] == '0' &&
 549             (msg[2] == '4' || msg[2] == '3' || msg[2] == '1')) {
 550                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 551                 smtp_session->state = SMTP_ERROR;
 552                 smtp_session->error_val = SM_ERROR;
 553                 g_free(smtp_session->error_msg);
 554                 smtp_session->error_msg = g_strdup(msg);
 555                 return -1;
 556         }
 557
 558         if (!strncmp(msg, "535", 3)) {
 559                 log_warning(LOG_PROTOCOL, _("error occurred on authentication\n"));
 560                 smtp_session->state = SMTP_ERROR;
 561                 smtp_session->error_val = SM_AUTHFAIL;
 562                 g_free(smtp_session->error_msg);
 563                 smtp_session->error_msg = g_strdup(msg);
 564                 return -1;
 565         }
 566
 567         if (msg[0] != '1' && msg[0] != '2' && msg[0] != '3') {
 568                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 569                 smtp_session->state = SMTP_ERROR;
 570                 smtp_session->error_val = SM_ERROR;
 571                 g_free(smtp_session->error_msg);
 572                 smtp_session->error_msg = g_strdup(msg);
 573                 return -1;
 574         }
 575
 576         if (msg[3] == '-')
 577                 cont = TRUE;
 578         else if (msg[3] != ' ' && msg[3] != '\0') {
 579                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 580                 smtp_session->state = SMTP_ERROR;
 581                 smtp_session->error_val = SM_UNRECOVERABLE;
 582                 return -1;
 583         }
 584
 585         switch (smtp_session->state) {
 586         case SMTP_READY:
 587                 if (strstr(msg, "ESMTP"))
 588                         smtp_session->is_esmtp = TRUE;
 589         case SMTP_CONNECTED:
 590 #ifdef USE_GNUTLS
 591                 if (smtp_session->user || session->ssl_type != SSL_NONE ||
 592                     smtp_session->is_esmtp)
 593 #else
 594                 if (smtp_session->user || smtp_session->is_esmtp)
 595 #endif
 596                         ret = smtp_ehlo(smtp_session);
 597                 else
 598                         ret = smtp_helo(smtp_session);
 599                 break;
 600         case SMTP_HELO:
 601                 ret = smtp_from(smtp_session);
 602                 break;
 603         case SMTP_EHLO:
 604                 ret = smtp_ehlo_recv(smtp_session, msg);
 605                 if (cont == TRUE)
 606                         break;
 607                 if (smtp_session->max_message_size > 0
 608                 && smtp_session->max_message_size <
 609                    smtp_session->send_data_len) {
 610                         log_warning(LOG_PROTOCOL, _("Message is too big "
 611                               "(Maximum size is %s)\n"),
 612                               to_human_readable(
 613                                (goffset)(smtp_session->max_message_size)));
 614                         smtp_session->state = SMTP_ERROR;
 615                         smtp_session->error_val = SM_ERROR;
 616                         return -1;
 617                 }
 618 #ifdef USE_GNUTLS
 619                 if (session->ssl_type == SSL_STARTTLS &&
 620                     smtp_session->tls_init_done == FALSE) {
 621                         ret = smtp_starttls(smtp_session);
 622                         break;
 623                 }
 624 #endif
 625                 if (smtp_session->user) {
 626                         if (smtp_auth(smtp_session) != SM_OK) {
 627 #ifdef USE_GNUTLS
 628                                 if (session->ssl_type == SSL_NONE
 629                                 &&  smtp_session->tls_init_done == FALSE
 630                                 &&  (smtp_session->avail_auth_type & SMTPAUTH_TLS_AVAILABLE))
 631                                         ret = smtp_starttls(smtp_session);
 632                                 else
 633 #endif
 634                                         ret = smtp_from(smtp_session);
 635                         }
 636                 } else
 637                         ret = smtp_from(smtp_session);
 638                 break;
 639         case SMTP_STARTTLS:
 640 #ifdef USE_GNUTLS
 641                 if (session_start_tls(session) < 0) {
 642                         log_warning(LOG_PROTOCOL, _("couldn't start TLS session\n"));
 643                         smtp_session->state = SMTP_ERROR;
 644                         smtp_session->error_val = SM_ERROR;
 645                         return -1;
 646                 }
 647                 smtp_session->tls_init_done = TRUE;
 648                 ret = smtp_ehlo(smtp_session);
 649 #endif
 650                 break;
 651         case SMTP_AUTH:
 652                 ret = smtp_auth_recv(smtp_session, msg);
 653                 break;
 654         case SMTP_AUTH_LOGIN_USER:
 655                 ret = smtp_auth_login_user_recv(smtp_session, msg);
 656                 break;
 657         case SMTP_AUTH_PLAIN:
 658         case SMTP_AUTH_LOGIN_PASS:
 659         case SMTP_AUTH_CRAM_MD5:
 660                 ret = smtp_from(smtp_session);
 661                 break;
 662         case SMTP_FROM:
 663                 if (smtp_session->cur_to)
 664                         ret = smtp_rcpt(smtp_session);
 665                 break;
 666         case SMTP_RCPT:
 667                 if (smtp_session->cur_to)
 668                         ret = smtp_rcpt(smtp_session);
 669                 else
 670                         ret = smtp_data(smtp_session);
 671                 break;
 672         case SMTP_DATA:
 673                 ret = smtp_send_data(smtp_session);
 674                 break;
 675         case SMTP_EOM:
 676                 smtp_make_ready(smtp_session);
 677                 break;
 678         case SMTP_QUIT:
 679                 session_disconnect(session);
 680                 break;
 681         case SMTP_ERROR:
 682         default:
 683                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 684                 smtp_session->error_val = SM_ERROR;
 685                 return -1;
 686         }
 687
 688         if (cont && ret == SM_OK)
 689                 return session_recv_msg(session);
 690
 691         if (ret != SM_OK)
 692                 smtp_session->error_val = SM_ERROR;
 693
 694         return ret == SM_OK ? 0 : -1;
 695 }
 696
 697 static gint smtp_session_send_data_finished(Session *session, guint len)
 698 {
 699         return smtp_eom(SMTP_SESSION(session));
 700 }