libcurl extracted to the separate lib

git-svn-id: http://svn.miranda-ng.org/main/trunk@14683 1316c22d-e87f-b044-9b9b-93d7a3e3ba9c

1 files changed, 1921 insertions, 0 deletions

diff --git a/libs/libcurl/src/smtp.c b/libs/libcurl/src/smtp.c
new file mode 100644
index 0000000000..9626a30d83
--- /dev/null
+++ b/libs/libcurl/src/smtp.c
@@ -0,0 +1,1921 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * RFC1870 SMTP Service Extension for Message Size
+ * RFC2195 CRAM-MD5 authentication
+ * RFC2831 DIGEST-MD5 authentication
+ * RFC3207 SMTP over TLS
+ * RFC4422 Simple Authentication and Security Layer (SASL)
+ * RFC4616 PLAIN authentication
+ * RFC4954 SMTP Authentication
+ * RFC5321 SMTP protocol
+ * RFC6749 OAuth 2.0 Authorization Framework
+ * Draft   SMTP URL Interface
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#ifndef CURL_DISABLE_SMTP
+
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#ifdef HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+#ifdef HAVE_UTSNAME_H
+#include <sys/utsname.h>
+#endif
+#ifdef HAVE_NETDB_H
+#include <netdb.h>
+#endif
+#ifdef __VMS
+#include <in.h>
+#include <inet.h>
+#endif
+
+#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
+#undef in_addr_t
+#define in_addr_t unsigned long
+#endif
+
+#include <curl/curl.h>
+#include "urldata.h"
+#include "sendf.h"
+#include "if2ip.h"
+#include "hostip.h"
+#include "progress.h"
+#include "transfer.h"
+#include "escape.h"
+#include "http.h" /* for HTTP proxy tunnel stuff */
+#include "socks.h"
+#include "smtp.h"
+
+#include "strtoofft.h"
+#include "strequal.h"
+#include "sslgen.h"
+#include "connect.h"
+#include "strerror.h"
+#include "select.h"
+#include "multiif.h"
+#include "url.h"
+#include "rawstr.h"
+#include "curl_gethostname.h"
+#include "curl_sasl.h"
+#include "warnless.h"
+
+#define _MPRINTF_REPLACE /* use our functions only */
+#include <curl/mprintf.h>
+
+#include "curl_memory.h"
+/* The last #include file should be: */
+#include "memdebug.h"
+
+/* Local API functions */
+static CURLcode smtp_regular_transfer(struct connectdata *conn, bool *done);
+static CURLcode smtp_do(struct connectdata *conn, bool *done);
+static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
+                          bool premature);
+static CURLcode smtp_connect(struct connectdata *conn, bool *done);
+static CURLcode smtp_disconnect(struct connectdata *conn, bool dead);
+static CURLcode smtp_multi_statemach(struct connectdata *conn, bool *done);
+static int smtp_getsock(struct connectdata *conn, curl_socket_t *socks,
+                        int numsocks);
+static CURLcode smtp_doing(struct connectdata *conn, bool *dophase_done);
+static CURLcode smtp_setup_connection(struct connectdata *conn);
+static CURLcode smtp_parse_url_options(struct connectdata *conn);
+static CURLcode smtp_parse_url_path(struct connectdata *conn);
+
+/*
+ * SMTP protocol handler.
+ */
+
+const struct Curl_handler Curl_handler_smtp = {
+  "SMTP",                           /* scheme */
+  smtp_setup_connection,            /* setup_connection */
+  smtp_do,                          /* do_it */
+  smtp_done,                        /* done */
+  ZERO_NULL,                        /* do_more */
+  smtp_connect,                     /* connect_it */
+  smtp_multi_statemach,             /* connecting */
+  smtp_doing,                       /* doing */
+  smtp_getsock,                     /* proto_getsock */
+  smtp_getsock,                     /* doing_getsock */
+  ZERO_NULL,                        /* domore_getsock */
+  ZERO_NULL,                        /* perform_getsock */
+  smtp_disconnect,                  /* disconnect */
+  ZERO_NULL,                        /* readwrite */
+  PORT_SMTP,                        /* defport */
+  CURLPROTO_SMTP,                   /* protocol */
+  PROTOPT_CLOSEACTION | PROTOPT_NOURLQUERY /* flags */
+};
+
+#ifdef USE_SSL
+/*
+ * SMTPS protocol handler.
+ */
+
+const struct Curl_handler Curl_handler_smtps = {
+  "SMTPS",                          /* scheme */
+  smtp_setup_connection,            /* setup_connection */
+  smtp_do,                          /* do_it */
+  smtp_done,                        /* done */
+  ZERO_NULL,                        /* do_more */
+  smtp_connect,                     /* connect_it */
+  smtp_multi_statemach,             /* connecting */
+  smtp_doing,                       /* doing */
+  smtp_getsock,                     /* proto_getsock */
+  smtp_getsock,                     /* doing_getsock */
+  ZERO_NULL,                        /* domore_getsock */
+  ZERO_NULL,                        /* perform_getsock */
+  smtp_disconnect,                  /* disconnect */
+  ZERO_NULL,                        /* readwrite */
+  PORT_SMTPS,                       /* defport */
+  CURLPROTO_SMTP | CURLPROTO_SMTPS, /* protocol */
+  PROTOPT_CLOSEACTION | PROTOPT_SSL
+  | PROTOPT_NOURLQUERY              /* flags */
+};
+#endif
+
+#ifndef CURL_DISABLE_HTTP
+/*
+ * HTTP-proxyed SMTP protocol handler.
+ */
+
+static const struct Curl_handler Curl_handler_smtp_proxy = {
+  "SMTP",                               /* scheme */
+  Curl_http_setup_conn,                 /* setup_connection */
+  Curl_http,                            /* do_it */
+  Curl_http_done,                       /* done */
+  ZERO_NULL,                            /* do_more */
+  ZERO_NULL,                            /* connect_it */
+  ZERO_NULL,                            /* connecting */
+  ZERO_NULL,                            /* doing */
+  ZERO_NULL,                            /* proto_getsock */
+  ZERO_NULL,                            /* doing_getsock */
+  ZERO_NULL,                            /* domore_getsock */
+  ZERO_NULL,                            /* perform_getsock */
+  ZERO_NULL,                            /* disconnect */
+  ZERO_NULL,                            /* readwrite */
+  PORT_SMTP,                            /* defport */
+  CURLPROTO_HTTP,                       /* protocol */
+  PROTOPT_NONE                          /* flags */
+};
+
+#ifdef USE_SSL
+/*
+ * HTTP-proxyed SMTPS protocol handler.
+ */
+
+static const struct Curl_handler Curl_handler_smtps_proxy = {
+  "SMTPS",                              /* scheme */
+  Curl_http_setup_conn,                 /* setup_connection */
+  Curl_http,                            /* do_it */
+  Curl_http_done,                       /* done */
+  ZERO_NULL,                            /* do_more */
+  ZERO_NULL,                            /* connect_it */
+  ZERO_NULL,                            /* connecting */
+  ZERO_NULL,                            /* doing */
+  ZERO_NULL,                            /* proto_getsock */
+  ZERO_NULL,                            /* doing_getsock */
+  ZERO_NULL,                            /* domore_getsock */
+  ZERO_NULL,                            /* perform_getsock */
+  ZERO_NULL,                            /* disconnect */
+  ZERO_NULL,                            /* readwrite */
+  PORT_SMTPS,                           /* defport */
+  CURLPROTO_HTTP,                       /* protocol */
+  PROTOPT_NONE                          /* flags */
+};
+#endif
+#endif
+
+#ifdef USE_SSL
+static void smtp_to_smtps(struct connectdata *conn)
+{
+  conn->handler = &Curl_handler_smtps;
+}
+#else
+#define smtp_to_smtps(x) Curl_nop_stmt
+#endif
+
+/***********************************************************************
+ *
+ * pop3_endofresp()
+ *
+ * Checks for an ending SMTP status code at the start of the given string, but
+ * also detects various capabilities from the EHLO response including the
+ * supported authentication mechanisms.
+ */
+static bool smtp_endofresp(struct connectdata *conn, char *line, size_t len,
+                           int *resp)
+{
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  bool result = FALSE;
+  size_t wordlen;
+
+  if(len < 4 || !ISDIGIT(line[0]) || !ISDIGIT(line[1]) || !ISDIGIT(line[2]))
+    return FALSE;       /* Nothing for us */
+
+  /* Do we have a command response? */
+  result = (line[3] == ' ') ? TRUE : FALSE;
+  if(result)
+    *resp = curlx_sltosi(strtol(line, NULL, 10));
+
+  /* Are we processing EHLO command data? */
+  if(smtpc->state == SMTP_EHLO && (!result || (result && *resp/100 == 2))) {
+    line += 4;
+    len -= 4;
+
+    /* Does the server support the STARTTLS capability? */
+    if(len >= 8 && !memcmp(line, "STARTTLS", 8))
+      smtpc->tls_supported = TRUE;
+
+    /* Does the server support the SIZE capability? */
+    else if(len >= 4 && !memcmp(line, "SIZE", 4))
+      smtpc->size_supported = TRUE;
+
+    /* Do we have the authentication mechanism list? */
+    else if(len >= 5 && !memcmp(line, "AUTH ", 5)) {
+      line += 5;
+      len -= 5;
+
+      /* Loop through the data line */
+      for(;;) {
+        while(len &&
+              (*line == ' ' || *line == '\t' ||
+               *line == '\r' || *line == '\n')) {
+
+          line++;
+          len--;
+        }
+
+        if(!len)
+          break;
+
+        /* Extract the word */
+        for(wordlen = 0; wordlen < len && line[wordlen] != ' ' &&
+              line[wordlen] != '\t' && line[wordlen] != '\r' &&
+              line[wordlen] != '\n';)
+          wordlen++;
+
+        /* Test the word for a matching authentication mechanism */
+        if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_LOGIN))
+          smtpc->authmechs |= SASL_MECH_LOGIN;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_PLAIN))
+          smtpc->authmechs |= SASL_MECH_PLAIN;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_CRAM_MD5))
+          smtpc->authmechs |= SASL_MECH_CRAM_MD5;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_DIGEST_MD5))
+          smtpc->authmechs |= SASL_MECH_DIGEST_MD5;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_GSSAPI))
+          smtpc->authmechs |= SASL_MECH_GSSAPI;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_EXTERNAL))
+          smtpc->authmechs |= SASL_MECH_EXTERNAL;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_NTLM))
+          smtpc->authmechs |= SASL_MECH_NTLM;
+        else if(sasl_mech_equal(line, wordlen, SASL_MECH_STRING_XOAUTH2))
+          smtpc->authmechs |= SASL_MECH_XOAUTH2;
+
+        line += wordlen;
+        len -= wordlen;
+      }
+    }
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * state()
+ *
+ * This is the ONLY way to change SMTP state!
+ */
+static void state(struct connectdata *conn, smtpstate newstate)
+{
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+#if defined(DEBUGBUILD) && !defined(CURL_DISABLE_VERBOSE_STRINGS)
+  /* for debug purposes */
+  static const char * const names[] = {
+    "STOP",
+    "SERVERGREET",
+    "EHLO",
+    "HELO",
+    "STARTTLS",
+    "UPGRADETLS",
+    "AUTH_PLAIN",
+    "AUTH_LOGIN",
+    "AUTH_LOGIN_PASSWD",
+    "AUTH_CRAMMD5",
+    "AUTH_DIGESTMD5",
+    "AUTH_DIGESTMD5_RESP",
+    "AUTH_NTLM",
+    "AUTH_NTLM_TYPE2MSG",
+    "AUTH_XOAUTH2",
+    "AUTH_FINAL",
+    "MAIL",
+    "RCPT",
+    "DATA",
+    "POSTDATA",
+    "QUIT",
+    /* LAST */
+  };
+
+  if(smtpc->state != newstate)
+    infof(conn->data, "SMTP %p state change from %s to %s\n",
+          (void *)smtpc, names[smtpc->state], names[newstate]);
+#endif
+
+  smtpc->state = newstate;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_ehlo()
+ *
+ * Sends the EHLO command to not only initialise communication with the ESMTP
+ * server but to also obtain a list of server side supported capabilities.
+ */
+static CURLcode smtp_perform_ehlo(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  smtpc->authmechs = 0;         /* No known authentication mechanisms yet */
+  smtpc->authused = 0;          /* Clear the authentication mechanism used
+                                   for esmtp connections */
+  smtpc->tls_supported = FALSE; /* Clear the TLS capability */
+
+  /* Send the EHLO command */
+  result = Curl_pp_sendf(&smtpc->pp, "EHLO %s", smtpc->domain);
+
+  if(!result)
+    state(conn, SMTP_EHLO);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_helo()
+ *
+ * Sends the HELO command to initialise communication with the SMTP server.
+ */
+static CURLcode smtp_perform_helo(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  smtpc->authused = 0;          /* No authentication mechanism used in smtp
+                                   connections */
+
+  /* Send the HELO command */
+  result = Curl_pp_sendf(&smtpc->pp, "HELO %s", smtpc->domain);
+
+  if(!result)
+    state(conn, SMTP_HELO);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_starttls()
+ *
+ * Sends the STLS command to start the upgrade to TLS.
+ */
+static CURLcode smtp_perform_starttls(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+
+  /* Send the STARTTLS command */
+  result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", "STARTTLS");
+
+  if(!result)
+    state(conn, SMTP_STARTTLS);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_upgrade_tls()
+ *
+ * Performs the upgrade to TLS.
+ */
+static CURLcode smtp_perform_upgrade_tls(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  /* Start the SSL connection */
+  result = Curl_ssl_connect_nonblocking(conn, FIRSTSOCKET, &smtpc->ssldone);
+
+  if(!result) {
+    if(smtpc->state != SMTP_UPGRADETLS)
+      state(conn, SMTP_UPGRADETLS);
+
+    if(smtpc->ssldone) {
+      smtp_to_smtps(conn);
+      result = smtp_perform_ehlo(conn);
+    }
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_authenticate()
+ *
+ * Sends an AUTH command allowing the client to login with the appropriate
+ * SASL authentication mechanism.
+ */
+static CURLcode smtp_perform_authenticate(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  const char *mech = NULL;
+  char *initresp = NULL;
+  size_t len = 0;
+  smtpstate state1 = SMTP_STOP;
+  smtpstate state2 = SMTP_STOP;
+
+  /* Check we have a username and password to authenticate with and end the
+     connect phase if we don't */
+  if(!conn->bits.user_passwd) {
+    state(conn, SMTP_STOP);
+
+    return result;
+  }
+
+  /* Calculate the supported authentication mechanism, by decreasing order of
+     security, as well as the initial response where appropriate */
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+  if((smtpc->authmechs & SASL_MECH_DIGEST_MD5) &&
+     (smtpc->prefmech & SASL_MECH_DIGEST_MD5)) {
+    mech = SASL_MECH_STRING_DIGEST_MD5;
+    state1 = SMTP_AUTH_DIGESTMD5;
+    smtpc->authused = SASL_MECH_DIGEST_MD5;
+  }
+  else if((smtpc->authmechs & SASL_MECH_CRAM_MD5) &&
+          (smtpc->prefmech & SASL_MECH_CRAM_MD5)) {
+    mech = SASL_MECH_STRING_CRAM_MD5;
+    state1 = SMTP_AUTH_CRAMMD5;
+    smtpc->authused = SASL_MECH_CRAM_MD5;
+  }
+  else
+#endif
+#ifdef USE_NTLM
+  if((smtpc->authmechs & SASL_MECH_NTLM) &&
+     (smtpc->prefmech & SASL_MECH_NTLM)) {
+    mech = SASL_MECH_STRING_NTLM;
+    state1 = SMTP_AUTH_NTLM;
+    state2 = SMTP_AUTH_NTLM_TYPE2MSG;
+    smtpc->authused = SASL_MECH_NTLM;
+
+    if(data->set.sasl_ir)
+      result = Curl_sasl_create_ntlm_type1_message(conn->user, conn->passwd,
+                                                   &conn->ntlm,
+                                                   &initresp, &len);
+    }
+  else
+#endif
+  if(((smtpc->authmechs & SASL_MECH_XOAUTH2) &&
+      (smtpc->prefmech & SASL_MECH_XOAUTH2) &&
+      (smtpc->prefmech != SASL_AUTH_ANY)) || conn->xoauth2_bearer) {
+    mech = SASL_MECH_STRING_XOAUTH2;
+    state1 = SMTP_AUTH_XOAUTH2;
+    state2 = SMTP_AUTH_FINAL;
+    smtpc->authused = SASL_MECH_XOAUTH2;
+
+    if(data->set.sasl_ir)
+      result = Curl_sasl_create_xoauth2_message(conn->data, conn->user,
+                                                conn->xoauth2_bearer,
+                                                &initresp, &len);
+  }
+  else if((smtpc->authmechs & SASL_MECH_LOGIN) &&
+     (smtpc->prefmech & SASL_MECH_LOGIN)) {
+    mech = SASL_MECH_STRING_LOGIN;
+    state1 = SMTP_AUTH_LOGIN;
+    state2 = SMTP_AUTH_LOGIN_PASSWD;
+    smtpc->authused = SASL_MECH_LOGIN;
+
+    if(data->set.sasl_ir)
+      result = Curl_sasl_create_login_message(conn->data, conn->user,
+                                              &initresp, &len);
+  }
+  else if((smtpc->authmechs & SASL_MECH_PLAIN) &&
+          (smtpc->prefmech & SASL_MECH_PLAIN)) {
+    mech = SASL_MECH_STRING_PLAIN;
+    state1 = SMTP_AUTH_PLAIN;
+    state2 = SMTP_AUTH_FINAL;
+    smtpc->authused = SASL_MECH_PLAIN;
+
+    if(data->set.sasl_ir)
+      result = Curl_sasl_create_plain_message(conn->data, conn->user,
+                                              conn->passwd, &initresp, &len);
+  }
+
+  if(!result) {
+    if(mech) {
+      /* Perform SASL based authentication */
+      if(initresp &&
+         8 + strlen(mech) + len <= 512) { /* AUTH <mech> ...<crlf> */
+        result = Curl_pp_sendf(&smtpc->pp, "AUTH %s %s", mech, initresp);
+
+        if(!result)
+          state(conn, state2);
+      }
+      else {
+        result = Curl_pp_sendf(&smtpc->pp, "AUTH %s", mech);
+
+        if(!result)
+          state(conn, state1);
+      }
+
+      Curl_safefree(initresp);
+    }
+    else {
+      /* Other mechanisms not supported */
+      infof(conn->data, "No known authentication mechanisms supported!\n");
+      result = CURLE_LOGIN_DENIED;
+    }
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_mail()
+ *
+ * Sends an MAIL command to initiate the upload of a message.
+ */
+static CURLcode smtp_perform_mail(struct connectdata *conn)
+{
+  char *from = NULL;
+  char *auth = NULL;
+  char *size = NULL;
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  /* Calculate the FROM parameter */
+  if(!data->set.str[STRING_MAIL_FROM])
+    /* Null reverse-path, RFC-5321, sect. 3.6.3 */
+    from = strdup("<>");
+  else if(data->set.str[STRING_MAIL_FROM][0] == '<')
+    from = aprintf("%s", data->set.str[STRING_MAIL_FROM]);
+  else
+    from = aprintf("<%s>", data->set.str[STRING_MAIL_FROM]);
+
+  if(!from)
+    return CURLE_OUT_OF_MEMORY;
+
+  /* Calculate the optional AUTH parameter */
+  if(data->set.str[STRING_MAIL_AUTH] && conn->proto.smtpc.authused) {
+    if(data->set.str[STRING_MAIL_AUTH][0] != '\0')
+      auth = aprintf("%s", data->set.str[STRING_MAIL_AUTH]);
+    else
+      /* Empty AUTH, RFC-2554, sect. 5 */
+      auth = strdup("<>");
+
+    if(!auth) {
+      Curl_safefree(from);
+
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* Calculate the optional SIZE parameter */
+  if(conn->proto.smtpc.size_supported && conn->data->set.infilesize > 0) {
+    size = aprintf("%" FORMAT_OFF_T, data->set.infilesize);
+
+    if(!size) {
+      Curl_safefree(from);
+      Curl_safefree(auth);
+
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* Send the MAIL command */
+  if(!auth && !size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s", from);
+  else if(auth && !size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s AUTH=%s", from, auth);
+  else if(auth && size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s AUTH=%s SIZE=%s", from, auth, size);
+  else
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s SIZE=%s", from, size);
+
+  Curl_safefree(from);
+  Curl_safefree(auth);
+  Curl_safefree(size);
+
+  if(!result)
+    state(conn, SMTP_MAIL);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_rcpt_to()
+ *
+ * Sends a RCPT TO command for a given recipient as part of the message upload
+ * process.
+ */
+static CURLcode smtp_perform_rcpt_to(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp = data->req.protop;
+
+  /* Send the RCPT TO command */
+  if(smtp->rcpt) {
+    if(smtp->rcpt->data[0] == '<')
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "RCPT TO:%s",
+                             smtp->rcpt->data);
+    else
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "RCPT TO:<%s>",
+                             smtp->rcpt->data);
+    if(!result)
+      state(conn, SMTP_RCPT);
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform_quit()
+ *
+ * Performs the quit action prior to sclose() being called.
+ */
+static CURLcode smtp_perform_quit(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+
+  /* Send the QUIT command */
+  result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", "QUIT");
+
+  if(!result)
+    state(conn, SMTP_QUIT);
+
+  return result;
+}
+
+/* For the initial server greeting */
+static CURLcode smtp_state_servergreet_resp(struct connectdata *conn,
+                                            int smtpcode,
+                                            smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode/100 != 2) {
+    failf(data, "Got unexpected smtp-server response: %d", smtpcode);
+    result = CURLE_FTP_WEIRD_SERVER_REPLY;
+  }
+  else
+    result = smtp_perform_ehlo(conn);
+
+  return result;
+}
+
+/* For STARTTLS responses */
+static CURLcode smtp_state_starttls_resp(struct connectdata *conn,
+                                         int smtpcode,
+                                         smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 220) {
+    if(data->set.use_ssl != CURLUSESSL_TRY) {
+      failf(data, "STARTTLS denied. %c", smtpcode);
+      result = CURLE_USE_SSL_FAILED;
+    }
+    else
+      result = smtp_perform_authenticate(conn);
+  }
+  else
+    result = smtp_perform_upgrade_tls(conn);
+
+  return result;
+}
+
+/* For EHLO responses */
+static CURLcode smtp_state_ehlo_resp(struct connectdata *conn, int smtpcode,
+                                     smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode/100 != 2) {
+    if((data->set.use_ssl <= CURLUSESSL_TRY || conn->ssl[FIRSTSOCKET].use) &&
+     !conn->bits.user_passwd)
+      result = smtp_perform_helo(conn);
+    else {
+      failf(data, "Remote access denied: %d", smtpcode);
+      result = CURLE_REMOTE_ACCESS_DENIED;
+    }
+  }
+  else if(data->set.use_ssl && !conn->ssl[FIRSTSOCKET].use) {
+    /* We don't have a SSL/TLS connection yet, but SSL is requested */
+    if(smtpc->tls_supported)
+      /* Switch to TLS connection now */
+      result = smtp_perform_starttls(conn);
+    else if(data->set.use_ssl == CURLUSESSL_TRY)
+      /* Fallback and carry on with authentication */
+      result = smtp_perform_authenticate(conn);
+    else {
+      failf(data, "STARTTLS not supported.");
+      result = CURLE_USE_SSL_FAILED;
+    }
+  }
+  else
+    result = smtp_perform_authenticate(conn);
+
+  return result;
+}
+
+/* For HELO responses */
+static CURLcode smtp_state_helo_resp(struct connectdata *conn, int smtpcode,
+                                     smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode/100 != 2) {
+    failf(data, "Remote access denied: %d", smtpcode);
+    result = CURLE_REMOTE_ACCESS_DENIED;
+  }
+  else
+    /* End of connect phase */
+    state(conn, SMTP_STOP);
+
+  return result;
+}
+
+/* For AUTH PLAIN (without initial response) responses */
+static CURLcode smtp_state_auth_plain_resp(struct connectdata *conn,
+                                           int smtpcode,
+                                           smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  size_t len = 0;
+  char *plainauth = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the authorisation message */
+    result = Curl_sasl_create_plain_message(conn->data, conn->user,
+                                            conn->passwd, &plainauth, &len);
+
+    /* Send the message */
+    if(!result) {
+      if(plainauth) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", plainauth);
+
+        if(!result)
+          state(conn, SMTP_AUTH_FINAL);
+      }
+
+      Curl_safefree(plainauth);
+    }
+  }
+
+  return result;
+}
+
+/* For AUTH LOGIN (without initial response) responses */
+static CURLcode smtp_state_auth_login_resp(struct connectdata *conn,
+                                           int smtpcode,
+                                           smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  size_t len = 0;
+  char *authuser = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the user message */
+    result = Curl_sasl_create_login_message(conn->data, conn->user,
+                                            &authuser, &len);
+
+    /* Send the user */
+    if(!result) {
+      if(authuser) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", authuser);
+
+        if(!result)
+          state(conn, SMTP_AUTH_LOGIN_PASSWD);
+      }
+
+      Curl_safefree(authuser);
+    }
+  }
+
+  return result;
+}
+
+/* For AUTH LOGIN user entry responses */
+static CURLcode smtp_state_auth_login_password_resp(struct connectdata *conn,
+                                                    int smtpcode,
+                                                    smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  size_t len = 0;
+  char *authpasswd = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the password message */
+    result = Curl_sasl_create_login_message(conn->data, conn->passwd,
+                                            &authpasswd, &len);
+
+    /* Send the password */
+    if(!result) {
+      if(authpasswd) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", authpasswd);
+
+        if(!result)
+          state(conn, SMTP_AUTH_FINAL);
+      }
+
+      Curl_safefree(authpasswd);
+    }
+  }
+
+  return result;
+}
+
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+/* For AUTH CRAM-MD5 responses */
+static CURLcode smtp_state_auth_cram_resp(struct connectdata *conn,
+                                          int smtpcode,
+                                          smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  char *chlg64 = data->state.buffer;
+  size_t len = 0;
+  char *rplyb64 = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    return CURLE_LOGIN_DENIED;
+  }
+
+  /* Get the challenge */
+  for(chlg64 += 4; *chlg64 == ' ' || *chlg64 == '\t'; chlg64++)
+    ;
+
+  /* Terminate the challenge */
+  if(*chlg64 != '=') {
+    for(len = strlen(chlg64); len--;)
+      if(chlg64[len] != '\r' && chlg64[len] != '\n' && chlg64[len] != ' ' &&
+         chlg64[len] != '\t')
+        break;
+
+    if(++len) {
+      chlg64[len] = '\0';
+    }
+  }
+
+  /* Create the response message */
+  result = Curl_sasl_create_cram_md5_message(data, chlg64, conn->user,
+                                             conn->passwd, &rplyb64, &len);
+
+  /* Send the response */
+  if(!result) {
+    if(rplyb64) {
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", rplyb64);
+
+      if(!result)
+        state(conn, SMTP_AUTH_FINAL);
+    }
+
+    Curl_safefree(rplyb64);
+  }
+
+  return result;
+}
+
+/* For AUTH DIGEST-MD5 challenge responses */
+static CURLcode smtp_state_auth_digest_resp(struct connectdata *conn,
+                                            int smtpcode,
+                                            smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  char *chlg64 = data->state.buffer;
+  size_t len = 0;
+  char *rplyb64 = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    return CURLE_LOGIN_DENIED;
+  }
+
+  /* Get the challenge */
+  for(chlg64 += 4; *chlg64 == ' ' || *chlg64 == '\t'; chlg64++)
+    ;
+
+  /* Create the response message */
+  result = Curl_sasl_create_digest_md5_message(data, chlg64, conn->user,
+                                               conn->passwd, "smtp",
+                                               &rplyb64, &len);
+
+  /* Send the response */
+  if(!result) {
+    if(rplyb64) {
+      result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", rplyb64);
+
+      if(!result)
+        state(conn, SMTP_AUTH_DIGESTMD5_RESP);
+    }
+
+    Curl_safefree(rplyb64);
+  }
+
+  return result;
+}
+
+/* For AUTH DIGEST-MD5 challenge-response responses */
+static CURLcode smtp_state_auth_digest_resp_resp(struct connectdata *conn,
+                                                 int smtpcode,
+                                                 smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Authentication failed: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Send an empty response */
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", "");
+
+    if(!result)
+      state(conn, SMTP_AUTH_FINAL);
+  }
+
+  return result;
+}
+
+#endif
+
+#ifdef USE_NTLM
+/* For AUTH NTLM (without initial response) responses */
+static CURLcode smtp_state_auth_ntlm_resp(struct connectdata *conn,
+                                          int smtpcode,
+                                          smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  char *type1msg = NULL;
+  size_t len = 0;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the type-1 message */
+    result = Curl_sasl_create_ntlm_type1_message(conn->user, conn->passwd,
+                                                 &conn->ntlm,
+                                                 &type1msg, &len);
+
+    /* Send the message */
+    if(!result) {
+      if(type1msg) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", type1msg);
+
+        if(!result)
+          state(conn, SMTP_AUTH_NTLM_TYPE2MSG);
+      }
+
+      Curl_safefree(type1msg);
+    }
+  }
+
+  return result;
+}
+
+/* For NTLM type-2 responses (sent in reponse to our type-1 message) */
+static CURLcode smtp_state_auth_ntlm_type2msg_resp(struct connectdata *conn,
+                                                   int smtpcode,
+                                                   smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  char *type3msg = NULL;
+  size_t len = 0;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the type-3 message */
+    result = Curl_sasl_create_ntlm_type3_message(data,
+                                                 data->state.buffer + 4,
+                                                 conn->user, conn->passwd,
+                                                 &conn->ntlm,
+                                                 &type3msg, &len);
+
+    /* Send the message */
+    if(!result) {
+      if(type3msg) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", type3msg);
+
+        if(!result)
+          state(conn, SMTP_AUTH_FINAL);
+      }
+
+      Curl_safefree(type3msg);
+    }
+  }
+
+  return result;
+}
+#endif
+
+/* For AUTH XOAUTH2 (without initial response) responses */
+static CURLcode smtp_state_auth_xoauth2_resp(struct connectdata *conn,
+                                             int smtpcode, smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  size_t len = 0;
+  char *xoauth = NULL;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 334) {
+    failf(data, "Access denied: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else {
+    /* Create the authorisation message */
+    result = Curl_sasl_create_xoauth2_message(conn->data, conn->user,
+                                              conn->xoauth2_bearer,
+                                              &xoauth, &len);
+
+    /* Send the message */
+    if(!result) {
+      if(xoauth) {
+        result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", xoauth);
+
+        if(!result)
+          state(conn, SMTP_AUTH_FINAL);
+      }
+
+      Curl_safefree(xoauth);
+    }
+  }
+
+  return result;
+}
+
+/* For the final responses to the AUTH sequence */
+static CURLcode smtp_state_auth_final_resp(struct connectdata *conn,
+                                           int smtpcode,
+                                           smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 235) {
+    failf(data, "Authentication failed: %d", smtpcode);
+    result = CURLE_LOGIN_DENIED;
+  }
+  else
+    /* End of connect phase */
+    state(conn, SMTP_STOP);
+
+  return result;
+}
+
+/* For MAIL responses */
+static CURLcode smtp_state_mail_resp(struct connectdata *conn, int smtpcode,
+                                     smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp = data->req.protop;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode/100 != 2) {
+    failf(data, "MAIL failed: %d", smtpcode);
+    result = CURLE_SEND_ERROR;
+    state(conn, SMTP_STOP);
+  }
+  else {
+    smtp->rcpt = data->set.mail_rcpt;
+
+    result = smtp_perform_rcpt_to(conn);
+  }
+
+  return result;
+}
+
+/* For RCPT responses */
+static CURLcode smtp_state_rcpt_resp(struct connectdata *conn, int smtpcode,
+                                     smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp = data->req.protop;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode/100 != 2) {
+    failf(data, "RCPT failed: %d", smtpcode);
+    result = CURLE_SEND_ERROR;
+    state(conn, SMTP_STOP);
+  }
+  else {
+    if(smtp->rcpt) {
+      smtp->rcpt = smtp->rcpt->next;
+      result = smtp_perform_rcpt_to(conn);
+
+      /* If we failed or still are sending RCPT data then return */
+      if(result || smtp->rcpt)
+        return result;
+    }
+
+    /* Send the DATA command */
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp, "%s", "DATA");
+
+    if(!result)
+      state(conn, SMTP_DATA);
+  }
+
+  return result;
+}
+
+/* For DATA response */
+static CURLcode smtp_state_data_resp(struct connectdata *conn, int smtpcode,
+                                     smtpstate instate)
+{
+  struct SessionHandle *data = conn->data;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 354) {
+    state(conn, SMTP_STOP);
+    return CURLE_SEND_ERROR;
+  }
+
+  /* Set the progress upload size */
+  Curl_pgrsSetUploadSize(data, data->set.infilesize);
+
+  /* SMTP upload */
+  Curl_setup_transfer(conn, -1, -1, FALSE, NULL, FIRSTSOCKET, NULL);
+
+  /* End of DO phase */
+  state(conn, SMTP_STOP);
+
+  return CURLE_OK;
+}
+
+/* For POSTDATA responses, which are received after the entire DATA
+   part has been sent to the server */
+static CURLcode smtp_state_postdata_resp(struct connectdata *conn,
+                                         int smtpcode,
+                                         smtpstate instate)
+{
+  CURLcode result = CURLE_OK;
+
+  (void)instate; /* no use for this yet */
+
+  if(smtpcode != 250)
+    result = CURLE_RECV_ERROR;
+
+  /* End of DONE phase */
+  state(conn, SMTP_STOP);
+
+  return result;
+}
+
+static CURLcode smtp_statemach_act(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  curl_socket_t sock = conn->sock[FIRSTSOCKET];
+  struct SessionHandle *data = conn->data;
+  int smtpcode;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  struct pingpong *pp = &smtpc->pp;
+  size_t nread = 0;
+
+  /* Busy upgrading the connection; right now all I/O is SSL/TLS, not SMTP */
+  if(smtpc->state == SMTP_UPGRADETLS)
+    return smtp_perform_upgrade_tls(conn);
+
+  /* Flush any data that needs to be sent */
+  if(pp->sendleft)
+    return Curl_pp_flushsend(pp);
+
+  /* Read the response from the server */
+  result = Curl_pp_readresp(sock, pp, &smtpcode, &nread);
+  if(result)
+    return result;
+
+  /* Store the latest response for later retrieval */
+  if(smtpc->state != SMTP_QUIT)
+    data->info.httpcode = smtpcode;
+
+  if(smtpcode) {
+    /* We have now received a full SMTP server response */
+    switch(smtpc->state) {
+    case SMTP_SERVERGREET:
+      result = smtp_state_servergreet_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_EHLO:
+      result = smtp_state_ehlo_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_HELO:
+      result = smtp_state_helo_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_STARTTLS:
+      result = smtp_state_starttls_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_PLAIN:
+      result = smtp_state_auth_plain_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_LOGIN:
+      result = smtp_state_auth_login_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_LOGIN_PASSWD:
+      result = smtp_state_auth_login_password_resp(conn, smtpcode,
+                                                   smtpc->state);
+      break;
+
+#ifndef CURL_DISABLE_CRYPTO_AUTH
+    case SMTP_AUTH_CRAMMD5:
+      result = smtp_state_auth_cram_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_DIGESTMD5:
+      result = smtp_state_auth_digest_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_DIGESTMD5_RESP:
+      result = smtp_state_auth_digest_resp_resp(conn, smtpcode, smtpc->state);
+      break;
+#endif
+
+#ifdef USE_NTLM
+    case SMTP_AUTH_NTLM:
+      result = smtp_state_auth_ntlm_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_NTLM_TYPE2MSG:
+      result = smtp_state_auth_ntlm_type2msg_resp(conn, smtpcode,
+                                                  smtpc->state);
+      break;
+#endif
+
+    case SMTP_AUTH_XOAUTH2:
+      result = smtp_state_auth_xoauth2_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_AUTH_FINAL:
+      result = smtp_state_auth_final_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_MAIL:
+      result = smtp_state_mail_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_RCPT:
+      result = smtp_state_rcpt_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_DATA:
+      result = smtp_state_data_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_POSTDATA:
+      result = smtp_state_postdata_resp(conn, smtpcode, smtpc->state);
+      break;
+
+    case SMTP_QUIT:
+      /* fallthrough, just stop! */
+    default:
+      /* internal error */
+      state(conn, SMTP_STOP);
+      break;
+    }
+  }
+
+  return result;
+}
+
+/* Called repeatedly until done from multi.c */
+static CURLcode smtp_multi_statemach(struct connectdata *conn, bool *done)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  if((conn->handler->flags & PROTOPT_SSL) && !smtpc->ssldone) {
+    result = Curl_ssl_connect_nonblocking(conn, FIRSTSOCKET, &smtpc->ssldone);
+    if(result || !smtpc->ssldone)
+      return result;
+  }
+
+  result = Curl_pp_statemach(&smtpc->pp, FALSE);
+  *done = (smtpc->state == SMTP_STOP) ? TRUE : FALSE;
+
+  return result;
+}
+
+static CURLcode smtp_block_statemach(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  while(smtpc->state != SMTP_STOP && !result)
+    result = Curl_pp_statemach(&smtpc->pp, TRUE);
+
+  return result;
+}
+
+/* Allocate and initialize the SMTP struct for the current SessionHandle if
+   required */
+static CURLcode smtp_init(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp;
+
+  smtp = data->req.protop = calloc(sizeof(struct SMTP), 1);
+  if(!smtp)
+    result = CURLE_OUT_OF_MEMORY;
+
+  return result;
+}
+
+/* For the SMTP "protocol connect" and "doing" phases only */
+static int smtp_getsock(struct connectdata *conn, curl_socket_t *socks,
+                        int numsocks)
+{
+  return Curl_pp_getsock(&conn->proto.smtpc.pp, socks, numsocks);
+}
+
+/***********************************************************************
+ *
+ * smtp_connect()
+ *
+ * This function should do everything that is to be considered a part of
+ * the connection phase.
+ *
+ * The variable pointed to by 'done' will be TRUE if the protocol-layer
+ * connect phase is done when this function returns, or FALSE if not.
+ */
+static CURLcode smtp_connect(struct connectdata *conn, bool *done)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  struct pingpong *pp = &smtpc->pp;
+
+  *done = FALSE; /* default to not done yet */
+
+  /* We always support persistent connections in SMTP */
+  conn->bits.close = FALSE;
+
+  /* Set the default response time-out */
+  pp->response_time = RESP_TIMEOUT;
+  pp->statemach_act = smtp_statemach_act;
+  pp->endofresp = smtp_endofresp;
+  pp->conn = conn;
+
+  /* Set the default preferred authentication mechanism */
+  smtpc->prefmech = SASL_AUTH_ANY;
+
+  /* Initialise the pingpong layer */
+  Curl_pp_init(pp);
+
+  /* Parse the URL options */
+  result = smtp_parse_url_options(conn);
+  if(result)
+    return result;
+
+  /* Parse the URL path */
+  result = smtp_parse_url_path(conn);
+  if(result)
+    return result;
+
+  /* Start off waiting for the server greeting response */
+  state(conn, SMTP_SERVERGREET);
+
+  result = smtp_multi_statemach(conn, done);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_done()
+ *
+ * The DONE function. This does what needs to be done after a single DO has
+ * performed.
+ *
+ * Input argument is already checked for validity.
+ */
+static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
+                          bool premature)
+{
+  CURLcode result = CURLE_OK;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp = data->req.protop;
+  struct pingpong *pp = &conn->proto.smtpc.pp;
+  const char *eob;
+  ssize_t len;
+  ssize_t bytes_written;
+
+  (void)premature;
+
+  if(!smtp)
+    /* When the easy handle is removed from the multi interface while libcurl
+       is still trying to resolve the host name, the SMTP struct is not yet
+       initialized. However, the removal action calls Curl_done() which in
+       turn calls this function, so we simply return success. */
+    return CURLE_OK;
+
+  if(status) {
+    conn->bits.close = TRUE; /* marked for closure */
+    result = status;         /* use the already set error code */
+  }
+  else if(!data->set.connect_only) {
+    /* Calculate the EOB taking into account any terminating CRLF from the
+       previous line of the email or the CRLF of the DATA command when there
+       is "no mail data". RFC-5321, sect. 4.1.1.4. */
+    eob = SMTP_EOB;
+    len = SMTP_EOB_LEN;
+    if(smtp->trailing_crlf || !conn->data->set.infilesize) {
+      eob += 2;
+      len -= 2;
+    }
+
+    /* Send the end of block data */
+    result = Curl_write(conn, conn->writesockfd, eob, len, &bytes_written);
+    if(result)
+      return result;
+
+    if(bytes_written != len) {
+      /* The whole chunk was not sent so keep it around and adjust the
+         pingpong structure accordingly */
+      pp->sendthis = strdup(eob);
+      pp->sendsize = len;
+      pp->sendleft = len - bytes_written;
+    }
+    else
+      /* Successfully sent so adjust the response timeout relative to now */
+      pp->response = Curl_tvnow();
+
+    state(conn, SMTP_POSTDATA);
+
+    /* Run the state-machine
+
+       TODO: when the multi interface is used, this _really_ should be using
+       the smtp_multi_statemach function but we have no general support for
+       non-blocking DONE operations, not in the multi state machine and with
+       Curl_done() invokes on several places in the code!
+    */
+    result = smtp_block_statemach(conn);
+  }
+
+  /* Clear the transfer mode for the next request */
+  smtp->transfer = FTPTRANSFER_BODY;
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_perform()
+ *
+ * This is the actual DO function for SMTP. Send a mail according to the
+ * options previously setup.
+ */
+static CURLcode smtp_perform(struct connectdata *conn, bool *connected,
+                             bool *dophase_done)
+{
+  /* This is SMTP and no proxy */
+  CURLcode result = CURLE_OK;
+
+  DEBUGF(infof(conn->data, "DO phase starts\n"));
+
+  if(conn->data->set.opt_no_body) {
+    /* Requested no body means no transfer */
+    struct SMTP *smtp = conn->data->req.protop;
+    smtp->transfer = FTPTRANSFER_INFO;
+  }
+
+  *dophase_done = FALSE; /* not done yet */
+
+  /* Start the first command in the DO phase */
+  result = smtp_perform_mail(conn);
+  if(result)
+    return result;
+
+  /* run the state-machine */
+  result = smtp_multi_statemach(conn, dophase_done);
+
+  *connected = conn->bits.tcpconnect[FIRSTSOCKET];
+
+  if(*dophase_done)
+    DEBUGF(infof(conn->data, "DO phase is complete\n"));
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_do()
+ *
+ * This function is registered as 'curl_do' function. It decodes the path
+ * parts etc as a wrapper to the actual DO function (smtp_perform).
+ *
+ * The input argument is already checked for validity.
+ */
+static CURLcode smtp_do(struct connectdata *conn, bool *done)
+{
+  CURLcode result = CURLE_OK;
+
+  *done = FALSE; /* default to false */
+
+  result = smtp_regular_transfer(conn, done);
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_disconnect()
+ *
+ * Disconnect from an SMTP server. Cleanup protocol-specific per-connection
+ * resources. BLOCKING.
+ */
+static CURLcode smtp_disconnect(struct connectdata *conn,
+                                bool dead_connection)
+{
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+  /* We cannot send quit unconditionally. If this connection is stale or
+     bad in any way, sending quit and waiting around here will make the
+     disconnect wait in vain and cause more problems than we need to. */
+
+  /* The SMTP session may or may not have been allocated/setup at this
+     point! */
+  if(!dead_connection && smtpc->pp.conn)
+    if(!smtp_perform_quit(conn))
+      (void)smtp_block_statemach(conn); /* ignore errors on QUIT */
+
+  /* Disconnect from the server */
+  Curl_pp_disconnect(&smtpc->pp);
+
+  /* Cleanup the SASL module */
+  Curl_sasl_cleanup(conn, smtpc->authused);
+
+  /* Cleanup our connection based variables */
+  Curl_safefree(smtpc->domain);
+
+  return CURLE_OK;
+}
+
+/* Call this when the DO phase has completed */
+static CURLcode smtp_dophase_done(struct connectdata *conn, bool connected)
+{
+  struct SMTP *smtp = conn->data->req.protop;
+
+  (void)connected;
+
+  if(smtp->transfer != FTPTRANSFER_BODY)
+    /* no data to transfer */
+    Curl_setup_transfer(conn, -1, -1, FALSE, NULL, -1, NULL);
+
+  return CURLE_OK;
+}
+
+/* Called from multi.c while DOing */
+static CURLcode smtp_doing(struct connectdata *conn, bool *dophase_done)
+{
+  CURLcode result = smtp_multi_statemach(conn, dophase_done);
+
+  if(result)
+    DEBUGF(infof(conn->data, "DO phase failed\n"));
+  else if(*dophase_done) {
+    result = smtp_dophase_done(conn, FALSE /* not connected */);
+
+    DEBUGF(infof(conn->data, "DO phase is complete\n"));
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_regular_transfer()
+ *
+ * The input argument is already checked for validity.
+ *
+ * Performs all commands done before a regular transfer between a local and a
+ * remote host.
+ */
+static CURLcode smtp_regular_transfer(struct connectdata *conn,
+                                      bool *dophase_done)
+{
+  CURLcode result = CURLE_OK;
+  bool connected = FALSE;
+  struct SessionHandle *data = conn->data;
+
+  /* Make sure size is unknown at this point */
+  data->req.size = -1;
+
+  /* Set the progress data */
+  Curl_pgrsSetUploadCounter(data, 0);
+  Curl_pgrsSetDownloadCounter(data, 0);
+  Curl_pgrsSetUploadSize(data, 0);
+  Curl_pgrsSetDownloadSize(data, 0);
+
+  /* Carry out the perform */
+  result = smtp_perform(conn, &connected, dophase_done);
+
+  /* Perform post DO phase operations if necessary */
+  if(!result && *dophase_done)
+    result = smtp_dophase_done(conn, connected);
+
+  return result;
+}
+
+static CURLcode smtp_setup_connection(struct connectdata *conn)
+{
+  struct SessionHandle *data = conn->data;
+  CURLcode result;
+
+  if(conn->bits.httpproxy && !data->set.tunnel_thru_httpproxy) {
+    /* Unless we have asked to tunnel SMTP operations through the proxy, we
+       switch and use HTTP operations only */
+#ifndef CURL_DISABLE_HTTP
+    if(conn->handler == &Curl_handler_smtp)
+      conn->handler = &Curl_handler_smtp_proxy;
+    else {
+#ifdef USE_SSL
+      conn->handler = &Curl_handler_smtps_proxy;
+#else
+      failf(data, "SMTPS not supported!");
+      return CURLE_UNSUPPORTED_PROTOCOL;
+#endif
+    }
+    /* set it up as a HTTP connection instead */
+    return conn->handler->setup_connection(conn);
+
+#else
+    failf(data, "SMTP over http proxy requires HTTP support built-in!");
+    return CURLE_UNSUPPORTED_PROTOCOL;
+#endif
+  }
+
+  /* Initialise the SMTP layer */
+  result = smtp_init(conn);
+  if(result)
+    return result;
+
+  data->state.path++;   /* don't include the initial slash */
+
+  return CURLE_OK;
+}
+
+/***********************************************************************
+ *
+ * smtp_parse_url_options()
+ *
+ * Parse the URL login options.
+ */
+static CURLcode smtp_parse_url_options(struct connectdata *conn)
+{
+  CURLcode result = CURLE_OK;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  const char *options = conn->options;
+  const char *ptr = options;
+
+  if(options) {
+    const char *key = ptr;
+
+    while(*ptr && *ptr != '=')
+        ptr++;
+
+    if(strnequal(key, "AUTH", 4)) {
+      const char *value = ptr + 1;
+
+      if(strequal(value, "*"))
+        smtpc->prefmech = SASL_AUTH_ANY;
+      else if(strequal(value, SASL_MECH_STRING_LOGIN))
+        smtpc->prefmech = SASL_MECH_LOGIN;
+      else if(strequal(value, SASL_MECH_STRING_PLAIN))
+        smtpc->prefmech = SASL_MECH_PLAIN;
+      else if(strequal(value, SASL_MECH_STRING_CRAM_MD5))
+        smtpc->prefmech = SASL_MECH_CRAM_MD5;
+      else if(strequal(value, SASL_MECH_STRING_DIGEST_MD5))
+        smtpc->prefmech = SASL_MECH_DIGEST_MD5;
+      else if(strequal(value, SASL_MECH_STRING_GSSAPI))
+        smtpc->prefmech = SASL_MECH_GSSAPI;
+      else if(strequal(value, SASL_MECH_STRING_NTLM))
+        smtpc->prefmech = SASL_MECH_NTLM;
+      else if(strequal(value, SASL_MECH_STRING_XOAUTH2))
+        smtpc->prefmech = SASL_MECH_XOAUTH2;
+      else
+        smtpc->prefmech = SASL_AUTH_NONE;
+    }
+    else
+      result = CURLE_URL_MALFORMAT;
+  }
+
+  return result;
+}
+
+/***********************************************************************
+ *
+ * smtp_parse_url_path()
+ *
+ * Parse the URL path into separate path components.
+ */
+static CURLcode smtp_parse_url_path(struct connectdata *conn)
+{
+  /* The SMTP struct is already initialised in smtp_connect() */
+  struct SessionHandle *data = conn->data;
+  struct smtp_conn *smtpc = &conn->proto.smtpc;
+  const char *path = data->state.path;
+  char localhost[HOSTNAME_MAX + 1];
+
+  /* Calculate the path if necessary */
+  if(!*path) {
+    if(!Curl_gethostname(localhost, sizeof(localhost)))
+      path = localhost;
+    else
+      path = "localhost";
+  }
+
+  /* URL decode the path and use it as the domain in our EHLO */
+  return Curl_urldecode(conn->data, path, 0, &smtpc->domain, NULL, TRUE);
+}
+
+CURLcode Curl_smtp_escape_eob(struct connectdata *conn, ssize_t nread)
+{
+  /* When sending a SMTP payload we must detect CRLF. sequences making sure
+     they are sent as CRLF.. instead, as a . on the beginning of a line will
+     be deleted by the server when not part of an EOB terminator and a
+     genuine CRLF.CRLF which isn't escaped will wrongly be detected as end of
+     data by the server
+  */
+  ssize_t i;
+  ssize_t si;
+  struct SessionHandle *data = conn->data;
+  struct SMTP *smtp = data->req.protop;
+
+  /* Do we need to allocate the scatch buffer? */
+  if(!data->state.scratch) {
+    data->state.scratch = malloc(2 * BUFSIZE);
+
+    if(!data->state.scratch) {
+      failf (data, "Failed to alloc scratch buffer!");
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* This loop can be improved by some kind of Boyer-Moore style of
+     approach but that is saved for later... */
+  for(i = 0, si = 0; i < nread; i++) {
+    if(SMTP_EOB[smtp->eob] == data->req.upload_fromhere[i]) {
+      smtp->eob++;
+
+      /* Is the EOB potentially the terminating CRLF? */
+      if(2 == smtp->eob || SMTP_EOB_LEN == smtp->eob)
+        smtp->trailing_crlf = TRUE;
+      else
+        smtp->trailing_crlf = FALSE;
+    }
+    else if(smtp->eob) {
+      /* A previous substring matched so output that first */
+      memcpy(&data->state.scratch[si], SMTP_EOB, smtp->eob);
+      si += smtp->eob;
+
+      /* Then compare the first byte */
+      if(SMTP_EOB[0] == data->req.upload_fromhere[i])
+        smtp->eob = 1;
+      else
+        smtp->eob = 0;
+
+      /* Reset the trailing CRLF flag as there was more data */
+      smtp->trailing_crlf = FALSE;
+    }
+
+    /* Do we have a match for CRLF. as per RFC-5321, sect. 4.5.2 */
+    if(SMTP_EOB_FIND_LEN == smtp->eob) {
+      /* Copy the replacement data to the target buffer */
+      memcpy(&data->state.scratch[si], SMTP_EOB_REPL, SMTP_EOB_REPL_LEN);
+      si += SMTP_EOB_REPL_LEN;
+      smtp->eob = 0;
+    }
+    else if(!smtp->eob)
+      data->state.scratch[si++] = data->req.upload_fromhere[i];
+  }
+
+  if(smtp->eob) {
+    /* A substring matched before processing ended so output that now */
+    memcpy(&data->state.scratch[si], SMTP_EOB, smtp->eob);
+    si += smtp->eob;
+    smtp->eob = 0;
+  }
+
+  if(si != nread) {
+    /* Only use the new buffer if we replaced something */
+    nread = si;
+
+    /* Upload from the new (replaced) buffer instead */
+    data->req.upload_fromhere = data->state.scratch;
+
+    /* Set the new amount too */
+    data->req.upload_present = nread;
+  }
+
+  return CURLE_OK;
+}
+
+#endif /* CURL_DISABLE_SMTP */