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 "utils.h"
  38 #include "log.h"
  39
  40 static void smtp_session_destroy(Session *session);
  41
  42 static gint smtp_auth(SMTPSession *session);
  43 #ifdef USE_GNUTLS
  44 static gint smtp_starttls(SMTPSession *session);
  45 #endif
  46 static gint smtp_auth_cram_md5(SMTPSession *session);
  47 static gint smtp_auth_login(SMTPSession *session);
  48 static gint smtp_auth_plain(SMTPSession *session);
  49
  50 static gint smtp_ehlo(SMTPSession *session);
  51 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg);
  52
  53 static gint smtp_helo(SMTPSession *session);
  54 static gint smtp_rcpt(SMTPSession *session);
  55 static gint smtp_data(SMTPSession *session);
  56 static gint smtp_send_data(SMTPSession *session);
  57 static gint smtp_make_ready(SMTPSession *session);
  58 static gint smtp_eom(SMTPSession *session);
  59
  60 static gint smtp_session_recv_msg(Session *session, const gchar *msg);
  61 static gint smtp_session_send_data_finished(Session *session, guint len);
  62
  63
  64 Session *smtp_session_new(void *prefs_account)
  65 {
  66         SMTPSession *session;
  67
  68         session = g_new0(SMTPSession, 1);
  69
  70         session_init(SESSION(session), prefs_account, TRUE);
  71
  72         SESSION(session)->type             = SESSION_SMTP;
  73
  74         SESSION(session)->recv_msg         = smtp_session_recv_msg;
  75
  76         SESSION(session)->recv_data_finished = NULL;
  77         SESSION(session)->send_data_finished = smtp_session_send_data_finished;
  78
  79         SESSION(session)->destroy          = smtp_session_destroy;
  80
  81         session->state                     = SMTP_READY;
  82
  83 #ifdef USE_GNUTLS
  84         session->tls_init_done             = FALSE;
  85 #endif
  86
  87         session->hostname                  = NULL;
  88         session->user                      = NULL;
  89         session->pass                      = NULL;
  90
  91         session->from                      = NULL;
  92         session->to_list                   = NULL;
  93         session->cur_to                    = NULL;
  94
  95         session->send_data                 = NULL;
  96         session->send_data_len             = 0;
  97
  98         session->max_message_size          = -1;
  99
 100         session->avail_auth_type           = 0;
 101         session->forced_auth_type          = 0;
 102         session->auth_type                 = 0;
 103         session->esmtp_flags               = 0;
 104
 105         session->error_val                 = SM_OK;
 106         session->error_msg                 = NULL;
 107
 108         return SESSION(session);
 109 }
 110
 111 static void smtp_session_destroy(Session *session)
 112 {
 113         SMTPSession *smtp_session = SMTP_SESSION(session);
 114
 115         g_free(smtp_session->hostname);
 116         g_free(smtp_session->user);
 117         g_free(smtp_session->pass);
 118         g_free(smtp_session->from);
 119
 120         g_free(smtp_session->send_data);
 121
 122         g_free(smtp_session->error_msg);
 123 }
 124
 125 gint smtp_from(SMTPSession *session)
 126 {
 127         gchar buf[MESSAGEBUFSIZE];
 128         gchar *mail_size = NULL;
 129
 130         cm_return_val_if_fail(session->from != NULL, SM_ERROR);
 131
 132         session->state = SMTP_FROM;
 133
 134         if (session->is_esmtp && (session->esmtp_flags & ESMTP_SIZE)!=0)
 135                 mail_size = g_strdup_printf(" SIZE=%d", session->send_data_len);
 136         else
 137                 mail_size = g_strdup("");
 138
 139
 140         if (strchr(session->from, '<'))
 141                 g_snprintf(buf, sizeof(buf), "MAIL FROM:%s%s", session->from,
 142                            mail_size);
 143         else
 144                 g_snprintf(buf, sizeof(buf), "MAIL FROM:<%s>%s", session->from,
 145                            mail_size);
 146
 147         g_free(mail_size);
 148
 149         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 150                 return SM_ERROR;
 151         log_print(LOG_PROTOCOL, "%sSMTP> %s\n", (session->is_esmtp?"E":""), buf);
 152
 153         return SM_OK;
 154 }
 155
 156 static gint smtp_auth(SMTPSession *session)
 157 {
 158
 159         cm_return_val_if_fail(session->user != NULL, SM_ERROR);
 160
 161         session->state = SMTP_AUTH;
 162
 163         if ((session->forced_auth_type == SMTPAUTH_CRAM_MD5
 164              || session->forced_auth_type == 0)
 165             &&
 166              (session->avail_auth_type & SMTPAUTH_CRAM_MD5) != 0)
 167                 smtp_auth_cram_md5(session);
 168         else if ((session->forced_auth_type == SMTPAUTH_LOGIN
 169                   || session->forced_auth_type == 0)
 170                  &&
 171                   (session->avail_auth_type & SMTPAUTH_LOGIN) != 0)
 172                 smtp_auth_login(session);
 173         else if ((session->forced_auth_type == SMTPAUTH_PLAIN
 174                   || session->forced_auth_type == 0)
 175                  &&
 176                   (session->avail_auth_type & SMTPAUTH_PLAIN) != 0)
 177                 smtp_auth_plain(session);
 178         else if (session->forced_auth_type == 0) {
 179                 log_warning(LOG_PROTOCOL, _("No SMTP AUTH method available\n"));
 180                 return SM_AUTHFAIL;
 181         } else {
 182                 log_warning(LOG_PROTOCOL, _("Selected SMTP AUTH method not available\n"));
 183                 return SM_AUTHFAIL;
 184         }
 185
 186         return SM_OK;
 187 }
 188
 189 static gint smtp_auth_recv(SMTPSession *session, const gchar *msg)
 190 {
 191         gchar buf[MESSAGEBUFSIZE], *tmp;
 192
 193         switch (session->auth_type) {
 194         case SMTPAUTH_LOGIN:
 195                 session->state = SMTP_AUTH_LOGIN_USER;
 196
 197                 if (!strncmp(msg, "334 ", 4)) {
 198                         tmp = g_base64_encode(session->user, strlen(session->user));
 199
 200                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 201                                          tmp) < 0) {
 202                                 g_free(tmp);
 203                                 return SM_ERROR;
 204                         }
 205                         g_free(tmp);
 206                         log_print(LOG_PROTOCOL, "ESMTP> [USERID]\n");
 207                 } else {
 208                         /* Server rejects AUTH */
 209                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 210                                          "*") < 0)
 211                                 return SM_ERROR;
 212                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 213                 }
 214                 break;
 215         case SMTPAUTH_CRAM_MD5:
 216                 session->state = SMTP_AUTH_CRAM_MD5;
 217
 218                 if (!strncmp(msg, "334 ", 4)) {
 219                         gchar *response;
 220                         gchar *response64;
 221                         gchar *challenge, *tmp;
 222                         gsize challengelen;
 223                         guchar hexdigest[33];
 224
 225                         tmp = g_base64_decode(msg + 4, &challengelen);
 226                         challenge = g_strndup(tmp, challengelen);
 227                         g_free(tmp);
 228                         log_print(LOG_PROTOCOL, "ESMTP< [Decoded: %s]\n", challenge);
 229
 230                         g_snprintf(buf, sizeof(buf), "%s", session->pass);
 231                         md5_hex_hmac(hexdigest, challenge, challengelen,
 232                                      buf, strlen(session->pass));
 233                         g_free(challenge);
 234
 235                         response = g_strdup_printf
 236                                 ("%s %s", session->user, hexdigest);
 237                         log_print(LOG_PROTOCOL, "ESMTP> [Encoded: %s]\n", response);
 238
 239                         response64 = g_base64_encode(response, strlen(response));
 240                         g_free(response);
 241
 242                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 243                                          response64) < 0) {
 244                                 g_free(response64);
 245                                 return SM_ERROR;
 246                         }
 247                         log_print(LOG_PROTOCOL, "ESMTP> %s\n", response64);
 248                         g_free(response64);
 249                 } else {
 250                         /* Server rejects AUTH */
 251                         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL,
 252                                          "*") < 0)
 253                                 return SM_ERROR;
 254                         log_print(LOG_PROTOCOL, "ESMTP> *\n");
 255                 }
 256                 break;
 257         case SMTPAUTH_DIGEST_MD5:
 258         default:
 259                 /* stop smtp_auth when no correct authtype */
 260                 if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "*") < 0)
 261                         return SM_ERROR;
 262                 log_print(LOG_PROTOCOL, "ESMTP> *\n");
 263                 break;
 264         }
 265
 266         return SM_OK;
 267 }
 268
 269 static gint smtp_auth_login_user_recv(SMTPSession *session, const gchar *msg)
 270 {
 271         gchar buf[MESSAGEBUFSIZE], *tmp;
 272         gsize len;
 273
 274         session->state = SMTP_AUTH_LOGIN_PASS;
 275
 276         if (!strncmp(msg, "334 ", 4)) {
 277                 tmp = g_base64_encode(session->pass, strlen(session->pass));
 278                 len = g_strlcat(buf, tmp, MESSAGEBUFSIZE);
 279                 if (len >= MESSAGEBUFSIZE) {
 280                         /* This should never happen, and even if it does, all it will do
 281                          * is send an incorrect password so auth will fail. That's why
 282                          * we're printing this debug message, so investigating user or dev
 283                          * will know what's wrong. */
 284                         debug_print("Truncation of password occured in g_strlcat().\n");
 285                 }
 286                 g_free(tmp);
 287         } else {
 288                 /* Server rejects AUTH */
 289                 g_snprintf(buf, sizeof(buf), "*");
 290         }
 291
 292         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 293                 return SM_ERROR;
 294
 295         log_print(LOG_PROTOCOL, "ESMTP> [PASSWORD]\n");
 296
 297         return SM_OK;
 298 }
 299
 300 static gint smtp_ehlo(SMTPSession *session)
 301 {
 302         gchar buf[MESSAGEBUFSIZE];
 303
 304         session->state = SMTP_EHLO;
 305
 306         session->avail_auth_type = 0;
 307
 308         g_snprintf(buf, sizeof(buf), "EHLO %s",
 309                    session->hostname ? session->hostname : get_domain_name());
 310         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 311                 return SM_ERROR;
 312         log_print(LOG_PROTOCOL, "ESMTP> %s\n", buf);
 313
 314         return SM_OK;
 315 }
 316
 317 static gint smtp_ehlo_recv(SMTPSession *session, const gchar *msg)
 318 {
 319         if (strncmp(msg, "250", 3) == 0) {
 320                 const gchar *p = msg;
 321                 p += 3;
 322                 if (*p == '-' || *p == ' ') p++;
 323                 if (g_ascii_strncasecmp(p, "AUTH", 4) == 0) {
 324                         p += 5;
 325                         if (strcasestr(p, "PLAIN"))
 326                                 session->avail_auth_type |= SMTPAUTH_PLAIN;
 327                         if (strcasestr(p, "LOGIN"))
 328                                 session->avail_auth_type |= SMTPAUTH_LOGIN;
 329                         if (strcasestr(p, "CRAM-MD5"))
 330                                 session->avail_auth_type |= SMTPAUTH_CRAM_MD5;
 331                         if (strcasestr(p, "DIGEST-MD5"))
 332                                 session->avail_auth_type |= SMTPAUTH_DIGEST_MD5;
 333                 }
 334                 if (g_ascii_strncasecmp(p, "SIZE", 4) == 0) {
 335                         p += 5;
 336                         session->max_message_size = atoi(p);
 337                         session->esmtp_flags |= ESMTP_SIZE;
 338                 }
 339                 if (g_ascii_strncasecmp(p, "STARTTLS", 8) == 0) {
 340                         p += 9;
 341                         session->avail_auth_type |= SMTPAUTH_TLS_AVAILABLE;
 342                 }
 343                 return SM_OK;
 344         } else if ((msg[0] == '1' || msg[0] == '2' || msg[0] == '3') &&
 345             (msg[3] == ' ' || msg[3] == '\0'))
 346                 return SM_OK;
 347         else if (msg[0] == '5' && msg[1] == '0' &&
 348                  (msg[2] == '4' || msg[2] == '3' || msg[2] == '1'))
 349                 return SM_ERROR;
 350
 351         return SM_ERROR;
 352 }
 353
 354 #ifdef USE_GNUTLS
 355 static gint smtp_starttls(SMTPSession *session)
 356 {
 357         session->state = SMTP_STARTTLS;
 358
 359         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "STARTTLS") < 0)
 360                 return SM_ERROR;
 361         log_print(LOG_PROTOCOL, "ESMTP> STARTTLS\n");
 362
 363         return SM_OK;
 364 }
 365 #endif
 366
 367 static gint smtp_auth_cram_md5(SMTPSession *session)
 368 {
 369         session->state = SMTP_AUTH;
 370         session->auth_type = SMTPAUTH_CRAM_MD5;
 371
 372         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "AUTH CRAM-MD5") < 0)
 373                 return SM_ERROR;
 374         log_print(LOG_PROTOCOL, "ESMTP> AUTH CRAM-MD5\n");
 375
 376         return SM_OK;
 377 }
 378
 379 static gint smtp_auth_plain(SMTPSession *session)
 380 {
 381         gchar buf[MESSAGEBUFSIZE], *b64buf, *out;
 382         gint len;
 383
 384         session->state = SMTP_AUTH_PLAIN;
 385         session->auth_type = SMTPAUTH_PLAIN;
 386
 387         memset(buf, 0, sizeof buf);
 388
 389         /* "\0user\0password" */
 390         len = sprintf(buf, "%c%s%c%s", '\0', session->user, '\0', session->pass);
 391         b64buf = g_base64_encode(buf, len);
 392         out = g_strconcat("AUTH PLAIN ", b64buf, NULL);
 393         g_free(b64buf);
 394
 395         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, out) < 0) {
 396                 g_free(out);
 397                 return SM_ERROR;
 398         }
 399
 400         g_free(out);
 401
 402         log_print(LOG_PROTOCOL, "ESMTP> [AUTH PLAIN]\n");
 403
 404         g_free(b64buf);
 405
 406         return SM_OK;
 407 }
 408
 409 static gint smtp_auth_login(SMTPSession *session)
 410 {
 411         session->state = SMTP_AUTH;
 412         session->auth_type = SMTPAUTH_LOGIN;
 413
 414         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "AUTH LOGIN") < 0)
 415                 return SM_ERROR;
 416         log_print(LOG_PROTOCOL, "ESMTP> AUTH LOGIN\n");
 417
 418         return SM_OK;
 419 }
 420
 421 static gint smtp_helo(SMTPSession *session)
 422 {
 423         gchar buf[MESSAGEBUFSIZE];
 424
 425         session->state = SMTP_HELO;
 426
 427         g_snprintf(buf, sizeof(buf), "HELO %s",
 428                    session->hostname ? session->hostname : get_domain_name());
 429         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 430                 return SM_ERROR;
 431         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 432
 433         return SM_OK;
 434 }
 435
 436 static gint smtp_rcpt(SMTPSession *session)
 437 {
 438         gchar buf[MESSAGEBUFSIZE];
 439         gchar *to;
 440
 441         cm_return_val_if_fail(session->cur_to != NULL, SM_ERROR);
 442
 443         session->state = SMTP_RCPT;
 444
 445         to = (gchar *)session->cur_to->data;
 446
 447         if (strchr(to, '<'))
 448                 g_snprintf(buf, sizeof(buf), "RCPT TO:%s", to);
 449         else
 450                 g_snprintf(buf, sizeof(buf), "RCPT TO:<%s>", to);
 451         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, buf) < 0)
 452                 return SM_ERROR;
 453         log_print(LOG_PROTOCOL, "SMTP> %s\n", buf);
 454
 455         session->cur_to = session->cur_to->next;
 456
 457         return SM_OK;
 458 }
 459
 460 static gint smtp_data(SMTPSession *session)
 461 {
 462         session->state = SMTP_DATA;
 463
 464         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "DATA") < 0)
 465                 return SM_ERROR;
 466         log_print(LOG_PROTOCOL, "SMTP> DATA\n");
 467
 468         return SM_OK;
 469 }
 470
 471 static gint smtp_send_data(SMTPSession *session)
 472 {
 473         session->state = SMTP_SEND_DATA;
 474
 475         session_send_data(SESSION(session), session->send_data,
 476                           session->send_data_len);
 477
 478         return SM_OK;
 479 }
 480
 481 static gint smtp_make_ready(SMTPSession *session)
 482 {
 483         session->state = SMTP_MAIL_SENT_OK;
 484
 485         return SM_OK;
 486 }
 487
 488 gint smtp_quit(SMTPSession *session)
 489 {
 490         session->state = SMTP_QUIT;
 491
 492         session_send_msg(SESSION(session), SESSION_MSG_NORMAL, "QUIT");
 493         log_print(LOG_PROTOCOL, "SMTP> QUIT\n");
 494
 495         return SM_OK;
 496 }
 497
 498 static gint smtp_eom(SMTPSession *session)
 499 {
 500         session->state = SMTP_EOM;
 501
 502         if (session_send_msg(SESSION(session), SESSION_MSG_NORMAL, ".") < 0)
 503                 return SM_ERROR;
 504         log_print(LOG_PROTOCOL, "SMTP> . (EOM)\n");
 505
 506         return SM_OK;
 507 }
 508
 509 static gint smtp_session_recv_msg(Session *session, const gchar *msg)
 510 {
 511         SMTPSession *smtp_session = SMTP_SESSION(session);
 512         gboolean cont = FALSE;
 513         gint ret = 0;
 514
 515         if (strlen(msg) < 4) {
 516                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 517                 return -1;
 518         }
 519
 520         switch (smtp_session->state) {
 521         case SMTP_EHLO:
 522         case SMTP_STARTTLS:
 523         case SMTP_AUTH:
 524         case SMTP_AUTH_PLAIN:
 525         case SMTP_AUTH_LOGIN_USER:
 526         case SMTP_AUTH_LOGIN_PASS:
 527         case SMTP_AUTH_CRAM_MD5:
 528                 log_print(LOG_PROTOCOL, "ESMTP< %s\n", msg);
 529                 break;
 530         default:
 531                 log_print(LOG_PROTOCOL, "SMTP< %s\n", msg);
 532                 break;
 533         }
 534
 535         /* ignore all multiline responses except for EHLO */
 536         if (msg[3] == '-' && smtp_session->state != SMTP_EHLO)
 537                 return session_recv_msg(session);
 538
 539         if (msg[0] == '5' && msg[1] == '0' &&
 540             (msg[2] == '4' || msg[2] == '3' || msg[2] == '1')) {
 541                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 542                 smtp_session->state = SMTP_ERROR;
 543                 smtp_session->error_val = SM_ERROR;
 544                 g_free(smtp_session->error_msg);
 545                 smtp_session->error_msg = g_strdup(msg);
 546                 return -1;
 547         }
 548
 549         if (!strncmp(msg, "535", 3)) {
 550                 log_warning(LOG_PROTOCOL, _("error occurred on authentication\n"));
 551                 smtp_session->state = SMTP_ERROR;
 552                 smtp_session->error_val = SM_AUTHFAIL;
 553                 g_free(smtp_session->error_msg);
 554                 smtp_session->error_msg = g_strdup(msg);
 555                 return -1;
 556         }
 557
 558         if (msg[0] != '1' && msg[0] != '2' && msg[0] != '3') {
 559                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 560                 smtp_session->state = SMTP_ERROR;
 561                 smtp_session->error_val = SM_ERROR;
 562                 g_free(smtp_session->error_msg);
 563                 smtp_session->error_msg = g_strdup(msg);
 564                 return -1;
 565         }
 566
 567         if (msg[3] == '-')
 568                 cont = TRUE;
 569         else if (msg[3] != ' ' && msg[3] != '\0') {
 570                 log_warning(LOG_PROTOCOL, _("bad SMTP response\n"));
 571                 smtp_session->state = SMTP_ERROR;
 572                 smtp_session->error_val = SM_UNRECOVERABLE;
 573                 return -1;
 574         }
 575
 576         switch (smtp_session->state) {
 577         case SMTP_READY:
 578                 if (strstr(msg, "ESMTP"))
 579                         smtp_session->is_esmtp = TRUE;
 580 #ifdef USE_GNUTLS
 581                 if (smtp_session->user || session->ssl_type != SSL_NONE ||
 582                     smtp_session->is_esmtp)
 583 #else
 584                 if (smtp_session->user || smtp_session->is_esmtp)
 585 #endif
 586                         ret = smtp_ehlo(smtp_session);
 587                 else
 588                         ret = smtp_helo(smtp_session);
 589                 break;
 590         case SMTP_HELO:
 591                 ret = smtp_from(smtp_session);
 592                 break;
 593         case SMTP_EHLO:
 594                 ret = smtp_ehlo_recv(smtp_session, msg);
 595                 if (cont == TRUE)
 596                         break;
 597                 if (smtp_session->max_message_size > 0
 598                 && smtp_session->max_message_size <
 599                    smtp_session->send_data_len) {
 600                         log_warning(LOG_PROTOCOL, _("Message is too big "
 601                               "(Maximum size is %s)\n"),
 602                               to_human_readable(
 603                                (goffset)(smtp_session->max_message_size)));
 604                         smtp_session->state = SMTP_ERROR;
 605                         smtp_session->error_val = SM_ERROR;
 606                         return -1;
 607                 }
 608 #ifdef USE_GNUTLS
 609                 if (session->ssl_type == SSL_STARTTLS &&
 610                     smtp_session->tls_init_done == FALSE) {
 611                         ret = smtp_starttls(smtp_session);
 612                         break;
 613                 }
 614 #endif
 615                 if (smtp_session->user) {
 616                         if (smtp_auth(smtp_session) != SM_OK) {
 617 #ifdef USE_GNUTLS
 618                                 if (session->ssl_type == SSL_NONE
 619                                 &&  smtp_session->tls_init_done == FALSE
 620                                 &&  (smtp_session->avail_auth_type & SMTPAUTH_TLS_AVAILABLE))
 621                                         ret = smtp_starttls(smtp_session);
 622                                 else
 623 #endif
 624                                         ret = smtp_from(smtp_session);
 625                         }
 626                 } else
 627                         ret = smtp_from(smtp_session);
 628                 break;
 629         case SMTP_STARTTLS:
 630 #ifdef USE_GNUTLS
 631                 if (session_start_tls(session) < 0) {
 632                         log_warning(LOG_PROTOCOL, _("couldn't start TLS session\n"));
 633                         smtp_session->state = SMTP_ERROR;
 634                         smtp_session->error_val = SM_ERROR;
 635                         return -1;
 636                 }
 637                 smtp_session->tls_init_done = TRUE;
 638                 ret = smtp_ehlo(smtp_session);
 639 #endif
 640                 break;
 641         case SMTP_AUTH:
 642                 ret = smtp_auth_recv(smtp_session, msg);
 643                 break;
 644         case SMTP_AUTH_LOGIN_USER:
 645                 ret = smtp_auth_login_user_recv(smtp_session, msg);
 646                 break;
 647         case SMTP_AUTH_PLAIN:
 648         case SMTP_AUTH_LOGIN_PASS:
 649         case SMTP_AUTH_CRAM_MD5:
 650                 ret = smtp_from(smtp_session);
 651                 break;
 652         case SMTP_FROM:
 653                 if (smtp_session->cur_to)
 654                         ret = smtp_rcpt(smtp_session);
 655                 break;
 656         case SMTP_RCPT:
 657                 if (smtp_session->cur_to)
 658                         ret = smtp_rcpt(smtp_session);
 659                 else
 660                         ret = smtp_data(smtp_session);
 661                 break;
 662         case SMTP_DATA:
 663                 ret = smtp_send_data(smtp_session);
 664                 break;
 665         case SMTP_EOM:
 666                 smtp_make_ready(smtp_session);
 667                 break;
 668         case SMTP_QUIT:
 669                 session_disconnect(session);
 670                 break;
 671         case SMTP_ERROR:
 672         default:
 673                 log_warning(LOG_PROTOCOL, _("error occurred on SMTP session\n"));
 674                 smtp_session->error_val = SM_ERROR;
 675                 return -1;
 676         }
 677
 678         if (cont && ret == SM_OK)
 679                 return session_recv_msg(session);
 680
 681         if (ret != SM_OK)
 682                 smtp_session->error_val = SM_ERROR;
 683
 684         return ret == SM_OK ? 0 : -1;
 685 }
 686
 687 static gint smtp_session_send_data_finished(Session *session, guint len)
 688 {
 689         return smtp_eom(SMTP_SESSION(session));
 690 }