[evolution-data-server] I#275 - SMTP: Add option to override HELO/EHLO address

[Milan Crha <mcrha src gnome org>]

commit 05af781e579c79fbc440e6f7ea7e31ec4c07e9b4
Author: Milan Crha <mcrha redhat com>
Date:   Wed Nov 25 19:00:32 2020 +0100

    I#275 - SMTP: Add option to override HELO/EHLO address
    
    Closes https://gitlab.gnome.org/GNOME/evolution-data-server/-/issues/275

 .../org.gnome.evolution-data-server.gschema.xml.in |  5 ++
 src/camel/providers/smtp/camel-smtp-transport.c    | 71 ++++++++++++++--------
 2 files changed, 49 insertions(+), 27 deletions(-)
---
diff --git a/data/org.gnome.evolution-data-server.gschema.xml.in 
b/data/org.gnome.evolution-data-server.gschema.xml.in
index 50857216d..7e2c9b85c 100644
--- a/data/org.gnome.evolution-data-server.gschema.xml.in
+++ b/data/org.gnome.evolution-data-server.gschema.xml.in
@@ -14,6 +14,11 @@
       <_summary>Whether to load photos of signers/encrypters</_summary>
       <_description>When set to “true”, tries to load also photo of the signers/encrypters, if available in 
the key/certificate.</_description>
     </key>
+    <key name="camel-smtp-helo-argument" type="s">
+      <default>''</default>
+      <_summary>Override SMTP HELO/EHLO argument</_summary>
+      <_description>When not empty, it's used as the SMTP HELO/EHLO argument, instead of the local host 
name/IP.</_description>
+    </key>
     <key name="network-monitor-gio-name" type="s">
       <default>''</default>
       <_summary>GIO name of the GNetworkMonitor to use for an ENetworkMonitor instance</_summary>
diff --git a/src/camel/providers/smtp/camel-smtp-transport.c b/src/camel/providers/smtp/camel-smtp-transport.c
index d49c54ed1..c6b5aebee 100644
--- a/src/camel/providers/smtp/camel-smtp-transport.c
+++ b/src/camel/providers/smtp/camel-smtp-transport.c
@@ -1440,11 +1440,10 @@ smtp_helo (CamelSmtpTransport *transport,
            GCancellable *cancellable,
            GError **error)
 {
-       gchar *name = NULL, *cmdbuf = NULL, *respbuf = NULL;
+       gchar *name, *cmdbuf = NULL, *respbuf = NULL;
        gboolean first_line = TRUE;
        const gchar *token;
-       GResolver *resolver;
-       GInetAddress *address;
+       GSettings *settings;
        GError *local_error = NULL;
 
        /* these are flags that we set, so unset them in case we
@@ -1459,37 +1458,55 @@ smtp_helo (CamelSmtpTransport *transport,
                transport->authtypes = NULL;
        }
 
-       resolver = g_resolver_get_default ();
-       address = g_inet_socket_address_get_address (
-               G_INET_SOCKET_ADDRESS (transport->local_address));
+       settings = g_settings_new ("org.gnome.evolution-data-server");
+       name = g_settings_get_string (settings, "camel-smtp-helo-argument");
+       g_clear_object (&settings);
 
-       name = g_resolver_lookup_by_address (
-               resolver, address, cancellable, &local_error);
+       if (name) {
+               g_strstrip (name);
 
-       /* Sanity check. */
-       g_return_val_if_fail (
-               ((name != NULL) && (local_error == NULL)) ||
-               ((name == NULL) && (local_error != NULL)), FALSE);
+               if (!*name)
+                       g_clear_pointer (&name, g_free);
 
-       if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
-               return FALSE;
+               if (name) {
+                       d (printf ("[SMTP] Overrides HELO/EHLO argument to '%s'\n", name));
+               }
+       }
 
-       g_clear_error (&local_error);
+       if (!name) {
+               GResolver *resolver;
+               GInetAddress *address;
 
-       /* Contains a dot, might be (like) an FQDN; if not, then use the IP */
-       if (!name || !strchr (name, '.')) {
-               GSocketFamily family;
-               gchar *string;
+               resolver = g_resolver_get_default ();
+               address = g_inet_socket_address_get_address (G_INET_SOCKET_ADDRESS 
(transport->local_address));
 
-               g_free (name);
+               name = g_resolver_lookup_by_address (resolver, address, cancellable, &local_error);
 
-               string = g_inet_address_to_string (address);
-               family = g_inet_address_get_family (address);
-               if (family == G_SOCKET_FAMILY_IPV6)
-                       name = g_strdup_printf ("[IPv6:%s]", string);
-               else
-                       name = g_strdup_printf ("[%s]", string);
-               g_free (string);
+               /* Sanity check. */
+               g_return_val_if_fail (
+                       ((name != NULL) && (local_error == NULL)) ||
+                       ((name == NULL) && (local_error != NULL)), FALSE);
+
+               if (g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+                       return FALSE;
+
+               g_clear_error (&local_error);
+
+               /* Contains a dot, might be (like) an FQDN; if not, then use the IP */
+               if (!name || !strchr (name, '.')) {
+                       GSocketFamily family;
+                       gchar *string;
+
+                       g_free (name);
+
+                       string = g_inet_address_to_string (address);
+                       family = g_inet_address_get_family (address);
+                       if (family == G_SOCKET_FAMILY_IPV6)
+                               name = g_strdup_printf ("[IPv6:%s]", string);
+                       else
+                               name = g_strdup_printf ("[%s]", string);
+                       g_free (string);
+               }
        }
 
        camel_operation_push_message (cancellable, _("SMTP Greeting"));