Merge branch 'enable-fragmentation'

This enables IKE fragmentation by default. And also increases the
default fragment size to 1280 bytes (the default for IPv6).

conf/options/charon.opt

@@ -100,11 +100,12 @@ charon.flush_auth_cfg = no
 charon.follow_redirects = yes
 	Whether to follow IKEv2 redirects (RFC 5685).
 
-charon.fragment_size = 0
+charon.fragment_size = 1280
 	Maximum size (complete IP datagram size in bytes) of a sent IKE fragment
-	when using proprietary IKEv1 or standardized IKEv2 fragmentation (0 for
-	address family specific	default values). If specified this limit is used
-	for both IPv4 and IPv6.
+	when using proprietary IKEv1 or standardized IKEv2 fragmentation, defaults
+	to 1280 (use 0 for address family specific default values, which uses a
+	lower value for IPv4).  If specified this limit is used for both IPv4 and
+	IPv6.
 
 charon.group
 	Name of the group the daemon changes to after startup.

man/ipsec.conf.5.in

@@ -445,14 +445,15 @@ force UDP encapsulation for ESP packets even if no NAT situation is detected.
 This may help to surmount restrictive firewalls. In order to force the peer to
 encapsulate packets, NAT detection payloads are faked.
 .TP
-.BR fragmentation " = yes | force | " no
+.BR fragmentation " = " yes "  | force | no"
 whether to use IKE fragmentation (proprietary IKEv1 extension or IKEv2
 fragmentation as per RFC 7383).  Acceptable values are
-.BR yes ,
+.B yes
+(the default),
 .B force
 and
-.B no
-(the default). Fragmented IKE messages sent by a peer are always accepted
+.BR no .
+Fragmented IKE messages sent by a peer are always accepted
 irrespective of the value of this option. If set to
 .BR yes ,
 and the peer supports it, larger IKE messages will be sent in fragments.

src/libcharon/plugins/vici/vici_config.c

@@ -1980,7 +1980,7 @@ CALLBACK(config_sn, bool,
 		.send_cert = CERT_SEND_IF_ASKED,
 		.version = IKE_ANY,
 		.remote_port = IKEV2_UDP_PORT,
-		.fragmentation = FRAGMENTATION_NO,
+		.fragmentation = FRAGMENTATION_YES,
 		.unique = UNIQUE_NO,
 		.keyingtries = 1,
 		.rekey_time = LFT_UNDEFINED,

src/libcharon/sa/ike_sa.c

@@ -2979,7 +2979,7 @@ ike_sa_t * ike_sa_create(ike_sa_id_t *ike_sa_id, bool initiator,
 		.flush_auth_cfg = lib->settings->get_bool(lib->settings,
 								"%s.flush_auth_cfg", FALSE, lib->ns),
 		.fragment_size = lib->settings->get_int(lib->settings,
-								"%s.fragment_size", 0, lib->ns),
+								"%s.fragment_size", 1280, lib->ns),
 		.follow_redirects = lib->settings->get_bool(lib->settings,
 								"%s.follow_redirects", TRUE, lib->ns),
 	);

src/starter/confread.c

@@ -222,6 +222,7 @@ static void conn_defaults(starter_conn_t *conn)
 	conn->dpd_delay             =  30; /* seconds */
 	conn->dpd_timeout           = 150; /* seconds */
 	conn->replay_window         = SA_REPLAY_WINDOW_DEFAULT;
+	conn->fragmentation         = FRAGMENTATION_YES;
 
 	conn->left.sendcert = CERT_SEND_IF_ASKED;
 	conn->right.sendcert = CERT_SEND_IF_ASKED;

src/swanctl/swanctl.opt

@@ -139,12 +139,12 @@ connections.<conn>.dpd_timeout = 0s
 	checking. For compatibility reasons, with IKEv1 a custom interval may be
 	specified; this option has no effect on connections using IKE2.
 
-connections.<conn>.fragmentation = no
+connections.<conn>.fragmentation = yes
 	Use IKE UDP datagram fragmentation.  (_yes_, _no_ or _force_).
 
 	Use IKE fragmentation (proprietary IKEv1 extension or RFC 7383 IKEv2
-	fragmentation).  Acceptable  values  are _yes_, _force_ and _no_ (the
-	default). Fragmented IKE messages sent by a peer are always accepted
+	fragmentation).  Acceptable  values  are _yes_ (the	default), _force_ and
+	_no_. Fragmented IKE messages sent by a peer are always accepted
 	irrespective of  the  value  of  this option. If set to _yes_, and the peer
 	supports it, oversized IKE messages will be sent in fragments.  If set  to
 	_force_  (only  supported  for IKEv1) the initial IKE message will already