Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/lib-imap/imap-keepalive.h b/src/lib-imap/imap-keepalive.h
new file mode 100644
index 0000000..238cdbd
--- /dev/null
+++ b/src/lib-imap/imap-keepalive.h
@@ -0,0 +1,24 @@
+#ifndef IMAP_KEEPALIVE_H
+#define IMAP_KEEPALIVE_H
+
+/* This function can be used to set IMAP IDLE keepalive notification timeout
+   interval so that the client gets the keepalive notifications at exactly the
+   same time for all the IMAP connections. This helps to reduce battery usage
+   in mobile devices.
+
+   One problem with this is that we don't really want to send the notifications
+   to everyone at the same time, because it would cause huge peaks of activity.
+   Basing the notifications on the username works well for one account, but
+   basing it on the IP address allows the client to get all of the
+   notifications at the same time for multiple accounts as well (of course
+   assuming Dovecot is running on all the servers :)
+
+   One potential downside to using IP is that if a proxy hides the client's IP
+   address, the notifications are sent to everyone at the same time. This can
+   be avoided by using a properly configured Dovecot proxy, but we'll also try
+   to avoid this by not doing it for the commonly used intranet IP ranges. */
+unsigned int
+imap_keepalive_interval_msecs(const char *username, const struct ip_addr *ip,
+			      unsigned int interval_secs);
+
+#endif