Add mp_mrru option

Some equipments seem not able to actually put options in Configure-Reject
messages, so we then have to disable MRRU by hand.

docs/manpages/startup-config.5

@@ -233,6 +233,14 @@ MTU of interface for L2TP traffic (default: 1500). Used to set link MRU and adju
 \f[R]
 .fi
 .PP
+\f[B]mp_mrru\f[R] (int)
+.IP
+.nf
+\f[C]
+MRRU for MP traffic (default: 1614). Can be set to 0 to disable MP negociation.
+\f[R]
+.fi
+.PP
 \f[B]l2tp_secret\f[R] (string)
 .PP
 The secret used by l2tpns for authenticating tunnel request.

docs/src/html/manual.md

@@ -150,6 +150,10 @@ should be set by a line like: set configstring \"value\" set ipaddress
 :   MTU of interface for L2TP traffic (default: `1500`). Used to set
     link MRU and adjust TCP MSS.
 
+`mp_mrru` (int)
+
+:   MRRU for MP traffic (default: `1614`). Can be set to 0 to disable MP negociation.
+
 `ppp_restart_time` (int); `ppp_max_configure` (int); `ppp_max_failure` (int)
 
 :   PPP counter and timer values, as described in §4.1 of

etc/startup-config.default

@@ -16,6 +16,9 @@ set l2tp_secret "secret"
 # MTU of interface for L2TP traffic
 #set l2tp_mtu 1500
 
+# MRRU for MP traffic
+#set l2tp_mtu 1614
+
 # PPP counter and timer values
 #set ppp_restart_time 3
 #set ppp_max_configure 10

l2tpns.c

@@ -129,6 +129,7 @@ config_descriptt config_values[] = {
 	CONFIG("random_device", random_device, STRING),
 	CONFIG("l2tp_secret", l2tp_secret, STRING),
 	CONFIG("l2tp_mtu", l2tp_mtu, INT),
+	CONFIG("mp_mrru", mp_mrru, INT),
 	CONFIG("ppp_restart_time", ppp_restart_time, INT),
 	CONFIG("ppp_max_configure", ppp_max_configure, INT),
 	CONFIG("ppp_max_failure", ppp_max_failure, INT),
@@ -3285,8 +3286,11 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr, uint16_t indexu
 					sess_local[s].ppp_mru = MRU;
 
 					// Set multilink options before sending initial LCP packet
-					sess_local[s].mp_mrru = 1614;
+					sess_local[s].mp_mrru = config->mp_mrru;
+					if (config->mp_mrru)
 						sess_local[s].mp_epdis = ntohl(config->iftun_address ? config->iftun_address : my_address);
+					else
+						sess_local[s].mp_epdis = 0;
 
 					sendlcp(s, t);
 					change_state(s, lcp, RequestSent);
@@ -5393,6 +5397,8 @@ static void update_config()
 	else if (config->l2tp_mtu < MINMTU)	config->l2tp_mtu = MINMTU;
 	else if (config->l2tp_mtu > MAXMTU)	config->l2tp_mtu = MAXMTU;
 
+	if (config->mp_mrru < 0)		config->mp_mrru = 1614; // default
+
 	// reset MRU/MSS globals
 	MRU = config->l2tp_mtu - L2TP_HDRS;
 	if (MRU > PPPoE_MRU)

l2tpns.h

@@ -684,6 +684,7 @@ typedef struct
 
 	char		l2tp_secret[64];		// L2TP shared secret
 	int		l2tp_mtu;			// MTU of interface used for L2TP
+	int		mp_mrru;			// MRRU of MP
 
 	char		random_device[256];		// random device path, defaults to RANDOMDEVICE
 

pppoe.c

@@ -661,8 +661,11 @@ static void pppoe_recv_PADR(uint8_t *pack, int size)
 	sess_local[sid].ppp_mru = MRU;
 
 	// Set multilink options before sending initial LCP packet
-	sess_local[sid].mp_mrru = 1614;
+	sess_local[sid].mp_mrru = config->mp_mrru;
+	if (config->mp_mrru)
 		sess_local[sid].mp_epdis = ntohl(config->iftun_address ? config->iftun_address : my_address);
+	else
+		sess_local[sid].mp_epdis = 0;
 
 	memcpy(session[sid].src_hwaddr, ethhdr->h_source, ETH_ALEN);
 	pppoe_send_PADS(sid, ethhdr->h_source, host_uniq_tag, relay_sid_tag, service_name_tag);