Various keepalive extensions

Add compatibility aliases for ProtocolKeepAlives and SetupTimeOut, supported
in previous versions of Debian's OpenSSH package but since superseded by
ServerAliveInterval.  (We're probably stuck with this bit for
compatibility.)

In batch mode, default ServerAliveInterval to five minutes.

Adjust documentation to match and to give some more advice on use of
keepalives.

Author: Ian Jackson <ian@chiark.greenend.org.uk>
Author: Matthew Vernon <matthew@debian.org>
Author: Colin Watson <cjwatson@debian.org>
Last-Update: 2018-10-19

Patch-Name: keepalive-extensions.patch

1 files changed, 12 insertions, 2 deletions

diff --git a/readconf.c b/readconf.c
index 29f3bd98d..3d0b6ff90 100644
--- a/readconf.c
+++ b/readconf.c
@@ -177,6 +177,7 @@ typedef enum {
         oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys,
         oFingerprintHash, oUpdateHostkeys, oHostbasedKeyTypes,
         oPubkeyAcceptedKeyTypes, oCASignatureAlgorithms, oProxyJump,
+        oProtocolKeepAlives, oSetupTimeOut,
         oIgnore, oIgnoredUnknownOption, oDeprecated, oUnsupported
 } OpCodes;
 
@@ -326,6 +327,8 @@ static struct {
         { "pubkeyacceptedkeytypes", oPubkeyAcceptedKeyTypes },
         { "ignoreunknown", oIgnoreUnknown },
         { "proxyjump", oProxyJump },
+        { "protocolkeepalives", oProtocolKeepAlives },
+        { "setuptimeout", oSetupTimeOut },
 
         { NULL, oBadOption }
 };
@@ -1440,6 +1443,8 @@ parse_keytypes:
                 goto parse_flag;
 
         case oServerAliveInterval:
+        case oProtocolKeepAlives: /* Debian-specific compatibility alias */
+        case oSetupTimeOut:       /* Debian-specific compatibility alias */
                 intptr = &options->server_alive_interval;
                 goto parse_time;
 
@@ -2133,8 +2138,13 @@ fill_default_options(Options * options)
                 options->rekey_interval = 0;
         if (options->verify_host_key_dns == -1)
                 options->verify_host_key_dns = 0;
-        if (options->server_alive_interval == -1)
-                options->server_alive_interval = 0;
+        if (options->server_alive_interval == -1) {
+                /* in batch mode, default is 5mins */
+                if (options->batch_mode == 1)
+                        options->server_alive_interval = 300;
+                else
+                        options->server_alive_interval = 0;
+        }
         if (options->server_alive_count_max == -1)
                 options->server_alive_count_max = 3;
         if (options->control_master == -1)