X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/57d13b822213468bc61f3916eda4e448196c14db..26fb3ab9ac7f01449073e9f39de7458b014e2a8b:/ppp.c?ds=inline

diff --git a/ppp.c b/ppp.c
index b2d84ec..9467ef1 100644
--- a/ppp.c
+++ b/ppp.c
@@ -1,6 +1,6 @@
 // L2TPNS PPP Stuff
 
-char const *cvs_id_ppp = "$Id: ppp.c,v 1.22 2004-11-05 23:18:54 bodea Exp $";
+char const *cvs_id_ppp = "$Id: ppp.c,v 1.28 2004-11-25 02:45:27 bodea Exp $";
 
 #include <stdio.h>
 #include <string.h>
@@ -23,8 +23,6 @@ extern u32 eth_tx;
 extern time_t time_now;
 extern struct configt *config;
 
-void sendccp(tunnelidt t, sessionidt s);
-
 // Process PAP messages
 void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {
@@ -75,10 +73,8 @@ void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		u8 b[MAXCONTROL];
 		u8 id = p[1];
 		u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
-		if (!p) {	// Failed to make ppp header!
-			LOG(1,0,0,0, "Failed to make PPP header in process pap!\n");
-			return;
-		}
+		if (!p) return;
+
 		if (session[s].ip)
 			*p = 2;			// ACK
 		else
@@ -224,7 +220,7 @@ void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l)
 	radiussend(r, RADIUSAUTH);
 }
 
-char *ppp_lcp_types[] = {
+static char *ppp_lcp_types[] = {
 	NULL,
 	"ConfigReq",
 	"ConfigAck",
@@ -240,7 +236,7 @@ char *ppp_lcp_types[] = {
 	"IdentRequest",
 };
 
-void dumplcp(u8 *p, int l)
+static void dumplcp(u8 *p, int l)
 {
 	int x = l - 4;
 	u8 *o = (p + 4);
@@ -384,14 +380,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 					LOG(2, session[s].ip, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
 					if (!response)
 					{
-						q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-						if (!q)
-						{
-							LOG(2, session[s].ip, s, t, " Failed to send packet.\n");
-							break;
-						}
+						q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+						if (!q) break;
 						response = *q++ = ConfigNak;
 					}
+
+					if ((q - b + 11) > sizeof(b))
+					{
+						LOG(2, session[s].ip, s, t, "LCP overflow for asyncmap ConfigNak.\n");
+						break;
+					}
+
 					*q++ = type;
 					*q++ = 6;
 					memset(q, 0, 4); // asyncmap 0
@@ -417,14 +416,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 
 						if (!response)
 						{
-							q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-							if (!q)
-							{
-								LOG(2, session[s].ip, s, t, " Failed to send packet.\n");
-								break;
-							}
+							q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+							if (!q) break;
 							response = *q++ = ConfigNak;
 						}
+
+						if ((q - b + length) > sizeof(b))
+						{
+							LOG(2, session[s].ip, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
+							break;
+						}
+
 						memcpy(q, o, length);
 						*(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
 						q += length;
@@ -444,15 +446,17 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 					LOG(2, session[s].ip, s, t, "    Rejecting PPP LCP Option type %d\n", type);
 					if (!response || response != ConfigRej) // drop nak in favour of rej
 					{
-						q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-						if (!q)
-						{
-							LOG(2, session[s].ip, s, t, " Failed to send packet.\n");
-							break;
-						}
+						q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
+						if (!q) return;
 						response = *q++ = ConfigRej;
 					}
 
+					if ((q - b + length) > sizeof(b))
+					{
+						LOG(2, session[s].ip, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
+						break;
+					}
+
 					memcpy(q, o, length);
 					q += length;
 			}
@@ -464,11 +468,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		{
 			// Send back a ConfigAck
 			q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-			if (!q)
-			{
-				LOG(3, session[s].ip, s, t, " failed to create packet.\n");
-				return;
-			}
+			if (!q) return;
 			response = *q = ConfigAck;
 		}
 
@@ -480,22 +480,18 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 	}
 	else if (*p == ConfigNak)
 	{
-		LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
+		LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak.  Ignoring\n");
 		if (config->debug > 3) dumplcp(p, l);
 		return ;
 	}
 	else if (*p == TerminateReq)
 	{
+		LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq.  Sending TerminateAck\n");
 		*p = TerminateAck;	// close
 		q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
-		if (!q)
-		{
-			LOG(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
-			return;
-		}
-		LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
-		sessionshutdown(s, "Remote end closed connection.");
+		if (!q) return;
 		tunnelsend(b, l + (q - b), t); // send it
+		sessionshutdown(s, "Remote end closed connection.");
 	}
 	else if (*p == TerminateAck)
 	{
@@ -503,15 +499,11 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 	}
 	else if (*p == EchoReq)
 	{
+		LOG(5, session[s].ip, s, t, "LCP: Received EchoReq.  Sending EchoReply\n");
 		*p = EchoReply;		// reply
 		*(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
 		q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-		if (!q)
-		{
-			LOG(3, session[s].ip, s, t, " failed to send EchoReply.\n");
-			return;
-		}
-		LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
+		if (!q) return;
 		tunnelsend(b, l + (q - b), t); // send it
 	}
 	else if (*p == EchoReply)
@@ -527,11 +519,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 			l = 1400;
 		}
 		q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
-		if (!q)
-		{
-			LOG(3, session[s].ip, s, t, "Failed to create IdentRej.\n");
-			return;
-		}
+		if (!q) return;
 		LOG_HEX(5, "LCPIdentRej", q, l + 4);
 		tunnelsend(b, 12 + 4 + l, t);
 	}
@@ -543,6 +531,26 @@ void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 	}
 }
 
+// find a PPP option, returns point to option, or 0 if not found
+static u8 *findppp(u8 *b, u8 mtype)
+{
+	u16 l = ntohs(*(u16 *) (b + 2));
+	if (l < 4)
+		return 0;
+	b += 4;
+	l -= 4;
+	while (l)
+	{
+		if (l < b[1] || !b[1])
+			return 0;		// faulty
+		if (*b == mtype)
+			return b;
+		l -= b[1];
+		b += b[1];
+	}
+	return 0;
+}
+
 // Process IPCP messages
 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {
@@ -580,6 +588,10 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		session[s].flags |= SF_IPCP_ACKED;
 
 		LOG(3, session[s].ip, s, t, "IPCP Acked, session is now active\n");
+
+		// clear  LCP_ACKED flag  for possible fast renegotiaion for routers
+		session[s].flags &= ~SF_LCP_ACKED;
+
 		return;
 	}
 	if (*p != ConfigReq)
@@ -615,10 +627,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 			u16 n = 4;
 			i = p + l;
 			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
-			{
-				LOG(2, 0, s, t, "Failed to send IPCP ConfigRej\n");
 				return;
-			}
+
 			*q = ConfigRej;
 			p += 4;
 			while (p < i && p[1])
@@ -672,10 +682,8 @@ void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 						inet_toa(htonl(session[s].ip)));
 			}
 			if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
-			{
-				LOG(2, 0, s, t, " Failed to send IPCP packet.\n");
 				return;
-			}
+
 			tunnelsend(b, l + (q - b), t); // send it
 		}
 	}
@@ -709,12 +717,6 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		return;
 	}
 
-	if (session[s].snoop_ip && session[s].snoop_port)
-	{
-		// Snooping this session
-		snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
-	}
-
 	// Add on the tun header
 	p -= 4;
 	*(u32 *)p = htonl(0x00000800);
@@ -725,16 +727,6 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		return;
 	}
 
-	session[s].cin += l - 4;
-	session[s].total_cin += l - 4;
-	sess_count[s].cin += l - 4;
-
-	session[s].pin++;
-	eth_tx += l - 4;
-
-	STAT(tun_tx_packets);
-	INC_STAT(tun_tx_bytes, l);
-
 	if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
 		tbf_queue_packet(session[s].tbf_in, p, l);
 		return;
@@ -746,8 +738,25 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
 		STAT(tun_tx_errors);
 		LOG(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
 			l, strerror(errno), tunfd, p);
+
+		return;
 	}
 
+	if (session[s].snoop_ip && session[s].snoop_port)
+	{
+		// Snooping this session
+		snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
+	}
+
+	session[s].cin += l - 4;
+	session[s].total_cin += l - 4;
+	sess_count[s].cin += l - 4;
+
+	session[s].pin++;
+	eth_tx += l - 4;
+
+	STAT(tun_tx_packets);
+	INC_STAT(tun_tx_bytes, l - 4);
 }
 
 //
@@ -757,11 +766,20 @@ void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
 void send_ipin(sessionidt s, u8 *buf, int len)
 {
 	LOG_HEX(5, "IP in throttled", buf, len);
+
 	if (write(tunfd, buf, len) < 0)
 	{
 		STAT(tun_tx_errors);
 		LOG(0, 0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
 			len, strerror(errno), tunfd, buf);
+
+		return;
+	}
+
+	if (session[s].snoop_ip && session[s].snoop_port)
+	{
+		// Snooping this session
+		snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
 	}
 
 	// Increment packet counters
@@ -771,47 +789,49 @@ void send_ipin(sessionidt s, u8 *buf, int len)
 
 	session[s].pin++;
 	eth_tx += len - 4;
+
+	STAT(tun_tx_packets);
+	INC_STAT(tun_tx_bytes, len - 4);
 }
 
 
 // Process CCP messages
 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
 {
+	u8 b[MAXCONTROL];
+	u8 *q;
 
 	CSTAT(call_processccp);
 
 	LOG_HEX(5, "CCP", p, l);
-	if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
+	switch (l > 1 ? *p : 0)
 	{
-		LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
-		STAT(tunnel_rx_errors);
-		return ;
-	}
-	// reject
-	{
-		u8 b[MAXCONTROL];
-		u8 *q;
-		if (*p == ConfigReq)
-		{
-			if (l < 6)
-			{
-				*p = ConfigAck;		// accept no compression
-			}
-			else
-			{
-				*p = ConfigRej;		// reject
-				sendccp(t, s);
-			}
-		}
+	case ConfigReq:
+		if (l < 6)
+			*p = ConfigAck;		// accept no compression
 		else
-			*p = TerminateAck;		// close
-		if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
-		{
-			LOG(1,0,0,0, "Failed to send CCP packet.\n");	
-			return;
-		}
-		tunnelsend(b, l + (q - b), t); // send it
+			*p = ConfigRej;		// reject
+
+		break;
+
+	case TerminateReq:
+	    	*p = TerminateAck;
+		break;
+
+	default:
+		if (l > 1)
+			LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
+		else
+			LOG(1, 0, s, t, "Short CCP packet\n");
+
+		STAT(tunnel_rx_errors);
+		return;
 	}
+
+	if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
+		return;
+
+	tunnelsend(b, l + (q - b), t); // send it
 }
 
 // send a CHAP PP packet
@@ -849,11 +869,8 @@ void sendchap(tunnelidt t, sessionidt s)
 		return ;
 	}
 	q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
-	if (!q)
-	{
-		LOG(1, 0, s, t, "failed to send CHAP challenge.\n");
-		return;
-	}
+	if (!q) return;
+
 	*q = 1;					// challenge
 	q[1] = radius[r].id;			// ID
 	q[4] = 16;				// length
@@ -868,8 +885,13 @@ void sendchap(tunnelidt t, sessionidt s)
 // returns start of PPP frame
 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
 {
-	if (size < 12)
-		return NULL;	// Need more space than this!!
+	if (size < 12) // Need more space than this!!
+	{
+		static int backtrace_count = 0;
+		LOG(0, session[s].ip, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
+		log_backtrace(backtrace_count, 5)
+		return NULL;
+	}
 
 	*(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
 	*(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
@@ -888,33 +910,18 @@ u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
 		b += 2;
 	}
 
-	if (l + 12 > size) {
-		LOG(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
-		return NULL;	// Run out of room to hold the packet!
+	if (l + 12 > size)
+	{
+		static int backtrace_count = 0;
+		LOG(2, session[s].ip, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
+		log_backtrace(backtrace_count, 5)
+		return NULL;
 	}
+
 	if (p && l)
 		memcpy(b, p, l);
-	return b;
-}
 
-// find a PPP option, returns point to option, or 0 if not found
-u8 *findppp(u8 *b, u8 mtype)
-{
-	u16 l = ntohs(*(u16 *) (b + 2));
-	if (l < 4)
-		return 0;
-	b += 4;
-	l -= 4;
-	while (l)
-	{
-		if (l < b[1] || !b[1])
-			return 0;		// faulty
-		if (*b == mtype)
-			return b;
-		l -= b[1];
-		b += b[1];
-	}
-	return 0;
+	return b;
 }
 
 // Send initial LCP ConfigReq
@@ -922,12 +929,9 @@ void initlcp(tunnelidt t, sessionidt s)
 {
 	char b[500] = {0}, *q;
 
-	q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
-	if (!q)
-	{
-		LOG(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
+	if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
 		return;
-	}
+
 	LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
 	*q = ConfigReq;
 	*(u8 *)(q + 1) = (time_now % 255) + 1; // ID
@@ -940,17 +944,3 @@ void initlcp(tunnelidt t, sessionidt s)
 	*(u16 *)(q + 12) = htons(PPPPAP); // PAP
 	tunnelsend(b, 12 + 14, t);
 }
-
-// Send CCP reply
-void sendccp(tunnelidt t, sessionidt s)
-{
-	char *q, b[500] = {0};
-
-	q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP);
-	*q = ConfigReq;
-	*(u8 *)(q + 1) = (time_now % 255) + 1; // ID
-	*(u16 *)(q + 2) = htons(4); // Length
-	LOG_HEX(5, "PPPCCP", q, 4);
-	tunnelsend(b, (q - b) + 4 , t);
-}
-