make MRU configurable, NAK config requests for larger values

Changes

@@ -1,7 +1,8 @@
-* Wed Sep 14 2005 Brendan O'Dea <bod@optus.net> 2.1.6
+* Thu Sep 15 2005 Brendan O'Dea <bod@optus.net> 2.1.6
 - Any traffic on a tunnel resets lastrec, not just control messages.
 - Use a unique identifier for LCP.
 - Fix Code-Reject/Protocol-Reject.
+- Make MRU configurable, NAK config requests for larger values.
 
 * Sat Sep 3 2005 Brendan O'Dea <bod@optus.net> 2.1.5
 - Avoid Code-Reject loop.

Docs/manual.html

@@ -192,6 +192,10 @@ PPP counter and timer values, as described in §4.1 of
 <a href="ftp://ftp.rfc-editor.org/in-notes/rfc1661.txt">RFC1661</a>.
 </LI>
 
+<LI><B>ppp_mru</B> (int)<BR>
+PPP link MRU (default: 1452).
+</LI>
+
 <LI><B>primary_dns</B> (ip address)
 <LI><B>secondary_dns</B> (ip address)<BR>
 Whenever a PPP connection is established, DNS servers will be sent to the

Docs/startup-config.5

@@ -2,7 +2,7 @@
 .de Id
 .ds Dt \\$4 \\$5
 ..
-.Id $Id: startup-config.5,v 1.13 2005-09-02 23:59:56 bodea Exp $
+.Id $Id: startup-config.5,v 1.14 2005-09-15 09:34:49 bodea Exp $
 .TH STARTUP-CONFIG 5 "\*(Dt" L2TPNS "File Formats and Conventions"
 .SH NAME
 startup\-config \- configuration file for l2tpns
@@ -73,6 +73,9 @@ Number of configure requests to send before giving up (default: 10).
 Number of Configure-Nak requests to send before sending a
 Configure-Reject (default: 5).
 .TP
+.B ppp_mru
+PPP link MRU (default: 1452).
+.TP
 .BR primary_dns , " secondary_dns"
 Whenever a PPP connection is established, DNS servers will be sent to the
 user, both a primary and a secondary.  If either is set to 0.0.0.0, then that

etc/startup-config.default

@@ -15,6 +15,9 @@ set l2tp_secret "secret"
 #set ppp_max_configure 10
 #set ppp_max_failure 5
 
+# Link MRU
+#set ppp_mru 1452
+
 # Only 2 DNS server entries are allowed
 set primary_dns 10.0.0.1
 set secondary_dns 10.0.0.2

l2tpns.c

@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.131 2005-09-13 14:27:14 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.132 2005-09-15 09:34:48 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -108,6 +108,7 @@ config_descriptt config_values[] = {
 	CONFIG("ppp_restart_time", ppp_restart_time, INT),
 	CONFIG("ppp_max_configure", ppp_max_configure, INT),
 	CONFIG("ppp_max_failure", ppp_max_failure, INT),
+	CONFIG("ppp_mru", ppp_mru, INT),
 	CONFIG("primary_dns", default_dns1, IPv4),
 	CONFIG("secondary_dns", default_dns2, IPv4),
 	CONFIG("primary_radius", radiusserver[0], IPv4),
@@ -2381,7 +2382,7 @@ void processudp(uint8_t *buf, int len, struct sockaddr_in *addr)
 					if (amagic == 0) amagic = time_now;
 					session[s].magic = amagic; // set magic number
 					session[s].l2tp_flags = aflags; // set flags received
-					session[s].mru = DEFAULT_MRU;
+					session[s].mru = config->ppp_mru;
 					controlnull(t); // ack
 
 					// start LCP
@@ -3500,6 +3501,7 @@ static void initdata(int optdebug, char *optconfig)
 	config->ppp_restart_time = 3;
 	config->ppp_max_configure = 10;
 	config->ppp_max_failure = 5;
+	config->ppp_mru = DEFAULT_MRU;
 	strcpy(config->random_device, RANDOMDEVICE);
 
 	log_stream = stderr;
@@ -4248,6 +4250,8 @@ static void update_config()
 		setbuf(log_stream, NULL);
 	}
 
+	if (config->ppp_mru < 0) config->ppp_mru = 0;
+
 	// Update radius
 	config->numradiusservers = 0;
 	for (i = 0; i < MAXRADSERVER; i++)

l2tpns.h

@@ -1,5 +1,5 @@
 // L2TPNS Global Stuff
-// $Id: l2tpns.h,v 1.89 2005-09-13 14:23:07 bodea Exp $
+// $Id: l2tpns.h,v 1.90 2005-09-15 09:34:49 bodea Exp $
 
 #ifndef __L2TPNS_H__
 #define __L2TPNS_H__
@@ -15,7 +15,7 @@
 #include <sys/types.h>
 #include <libcli.h>
 
-#define VERSION	"2.1.6"
+#define VERSION	"2.1.7"
 
 // Limits
 #define MAXTUNNEL	500		// could be up to 65535
@@ -519,6 +519,7 @@ typedef struct
 	int		ppp_restart_time;		// timeout for PPP restart
 	int		ppp_max_configure;		// max lcp configure requests to send
 	int		ppp_max_failure;		// max lcp configure naks to send
+	int		ppp_mru;			// MRU to advertise
 
 	char		radiussecret[64];
 	int		radius_accounting;

l2tpns.spec

@@ -43,5 +43,5 @@ rm -rf %{buildroot}
 %attr(644,root,root) /usr/share/man/man[58]/*
 
 %changelog
-* Wed Sep 14 2005 Brendan O'Dea <bod@optus.net> 2.1.6-1
+* Thu Sep 15 2005 Brendan O'Dea <bod@optus.net> 2.1.6-1
 - 2.1.6 release, see /usr/share/doc/l2tpns-2.1.6/Changes

ppp.c

@@ -1,6 +1,6 @@
 // L2TPNS PPP Stuff
 
-char const *cvs_id_ppp = "$Id: ppp.c,v 1.80 2005-09-13 14:23:07 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.81 2005-09-15 09:34:49 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
@@ -577,7 +577,18 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 			switch (type)
 			{
 				case 1: // Maximum-Receive-Unit
-					session[s].mru = ntohs(*(uint16_t *)(o + 2));
+					{
+						uint16_t mru = ntohs(*(uint16_t *)(o + 2));
+						if (!config->ppp_mru || mru <= config->ppp_mru)
+						{
+							session[s].mru = mru;
+							break;
+						}
+
+						LOG(3, s, t, "    Remote requesting MRU of %u.  Rejecting.\n", mru);
+						mru = htons(config->ppp_mru);
+						q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
+					}
 					break;
 
 				case 2: // Async-Control-Character-Map
@@ -738,8 +749,9 @@ void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 				case 1: // Maximum-Receive-Unit
 					if (*p == ConfigNak)
 					{
-						session[s].mru = ntohs(*(uint16_t *)(o + 2));
+						session[s].mru = 0;
-						LOG(3, s, t, "    Remote requested MRU of %u\n", session[s].mru);
+						LOG(3, s, t, "    Remote requested MRU of %u; removing option\n",
+							ntohs(*(uint16_t *)(o + 2)));
 					}
 					else
 					{